* [PATCH 01/79] block: rnull: adopt new formatting guidelines
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 9:14 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 02/79] block: rnull: add module parameters Andreas Hindborg
` (77 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Reformat `use` statements to have one item per line as required by the
updated Rust formatting guidelines. Apply a formatting workaround to
ensure `rustfmt` produces the expected output.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index a9d5e575a2c43..2c83b014b05e9 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -10,14 +10,21 @@
self,
mq::{
self,
- gen_disk::{self, GenDisk},
- Operations, TagSet,
+ gen_disk::{
+ self,
+ GenDisk, //
+ },
+ Operations,
+ TagSet, //
},
},
error::Result,
pr_info,
prelude::*,
- sync::{aref::ARef, Arc},
+ sync::{
+ aref::ARef,
+ Arc, //
+ },
};
use pin_init::PinInit;
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 01/79] block: rnull: adopt new formatting guidelines
2026-02-15 23:34 ` [PATCH 01/79] block: rnull: adopt new formatting guidelines Andreas Hindborg
@ 2026-03-16 9:14 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 9:14 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:48AM +0100, Andreas Hindborg wrote:
> Reformat `use` statements to have one item per line as required by the
> updated Rust formatting guidelines. Apply a formatting workaround to
> ensure `rustfmt` produces the expected output.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 02/79] block: rnull: add module parameters
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
2026-02-15 23:34 ` [PATCH 01/79] block: rnull: adopt new formatting guidelines Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 9:18 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 03/79] block: rnull: add macros to define configfs attributes Andreas Hindborg
` (76 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Module parameter support for Rust modules was merged a few releases back.
Add module parameter support to the rnull driver.
This allows the user to control the driver either via configfs or module
parameters, just like the C counterpart.
Please note that the rust module parameters do not support boolean values.
Flags that should have been booleans are parsed as integers and compared to
zero.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 51 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 49 insertions(+), 2 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 2c83b014b05e9..bd883a5061cab 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -19,11 +19,13 @@
},
},
error::Result,
- pr_info,
+ new_mutex, pr_info,
prelude::*,
+ str::CString,
sync::{
aref::ARef,
- Arc, //
+ Arc,
+ Mutex, //
},
};
use pin_init::PinInit;
@@ -34,20 +36,65 @@
authors: ["Andreas Hindborg"],
description: "Rust implementation of the C null block driver",
license: "GPL v2",
+ params: {
+ gb: u64 {
+ default: 4,
+ description: "Device capacity in GiB",
+ },
+ rotational: u8 {
+ default: 0,
+ description:
+ "Set the rotational feature for the device (0 for false, 1 for true). Default: 0",
+ },
+ bs: u32 {
+ default: 4096,
+ description: "Block size (in bytes)",
+ },
+ nr_devices: u64 {
+ default: 1,
+ description: "Number of devices to register",
+ },
+ irqmode: u8 {
+ default: 0,
+ description: "IRQ completion handler. 0-none, 1-softirq",
+ },
+ },
}
#[pin_data]
struct NullBlkModule {
#[pin]
configfs_subsystem: kernel::configfs::Subsystem<configfs::Config>,
+ #[pin]
+ param_disks: Mutex<KVec<GenDisk<NullBlkDevice>>>,
}
impl kernel::InPlaceModule for NullBlkModule {
fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
pr_info!("Rust null_blk loaded\n");
+ let mut disks = KVec::new();
+
+ let defer_init = move || -> Result<_, Error> {
+ for i in 0..(*module_parameters::nr_devices.value()) {
+ let name = CString::try_from_fmt(fmt!("rnullb{}", i))?;
+
+ let disk = NullBlkDevice::new(
+ &name,
+ *module_parameters::bs.value(),
+ *module_parameters::rotational.value() != 0,
+ *module_parameters::gb.value() * 1024,
+ (*module_parameters::irqmode.value()).try_into()?,
+ )?;
+ disks.push(disk, GFP_KERNEL)?;
+ }
+
+ Ok(disks)
+ };
+
try_pin_init!(Self {
configfs_subsystem <- configfs::subsystem(),
+ param_disks <- new_mutex!(defer_init()?),
})
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 02/79] block: rnull: add module parameters
2026-02-15 23:34 ` [PATCH 02/79] block: rnull: add module parameters Andreas Hindborg
@ 2026-03-16 9:18 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 9:18 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:49AM +0100, Andreas Hindborg wrote:
> Module parameter support for Rust modules was merged a few releases back.
> Add module parameter support to the rnull driver.
>
> This allows the user to control the driver either via configfs or module
> parameters, just like the C counterpart.
>
> Please note that the rust module parameters do not support boolean values.
> Flags that should have been booleans are parsed as integers and compared to
> zero.
Since this is uapi, you probably should support booleans here. Otherwise
it'd be breaking to change this to be a boolean later.
Otherwise lgtm.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 03/79] block: rnull: add macros to define configfs attributes
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
2026-02-15 23:34 ` [PATCH 01/79] block: rnull: adopt new formatting guidelines Andreas Hindborg
2026-02-15 23:34 ` [PATCH 02/79] block: rnull: add module parameters Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 9:23 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 04/79] block: rust: fix generation of bindings to `BLK_STS_.*` Andreas Hindborg
` (75 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Defining configfs attributes in rust is a bit verbose at the moment. Add
some macros to make the attribute definition less verbose.
The configfs Rust abstractions should eventually provide procedural macros
for this task. When we get more users of the configfs Rust abstractions, we
shall consider this task.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 134 +++++++++------------------------
drivers/block/rnull/configfs/macros.rs | 128 +++++++++++++++++++++++++++++++
2 files changed, 164 insertions(+), 98 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index ea38b27a9011c..eafa71dfc40d3 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -1,20 +1,41 @@
// SPDX-License-Identifier: GPL-2.0
-use super::{NullBlkDevice, THIS_MODULE};
+use super::{
+ NullBlkDevice,
+ THIS_MODULE, //
+};
use kernel::{
- block::mq::gen_disk::{GenDisk, GenDiskBuilder},
+ block::mq::gen_disk::{
+ GenDisk,
+ GenDiskBuilder, //
+ },
c_str,
- configfs::{self, AttributeOperations},
+ configfs::{
+ self,
+ AttributeOperations, //
+ },
configfs_attrs,
- fmt::{self, Write as _},
+ fmt::{
+ self,
+ Write as _, //
+ },
new_mutex,
page::PAGE_SIZE,
prelude::*,
- str::{kstrtobool_bytes, CString},
- sync::Mutex,
+ str::{
+ kstrtobool_bytes,
+ CString, //
+ },
+ sync::Mutex, //
+};
+use macros::{
+ configfs_simple_bool_field,
+ configfs_simple_field, //
};
use pin_init::PinInit;
+mod macros;
+
pub(crate) fn subsystem() -> impl PinInit<kernel::configfs::Subsystem<Config>, Error> {
let item_type = configfs_attrs! {
container: configfs::Subsystem<Config>,
@@ -166,99 +187,16 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
-#[vtable]
-impl configfs::AttributeOperations<1> for DeviceConfig {
- type Data = DeviceConfig;
-
- fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
- let mut writer = kernel::str::Formatter::new(page);
- writer.write_fmt(fmt!("{}\n", this.data.lock().block_size))?;
- Ok(writer.bytes_written())
- }
-
- fn store(this: &DeviceConfig, page: &[u8]) -> Result {
- if this.data.lock().powered {
- return Err(EBUSY);
- }
-
- let text = core::str::from_utf8(page)?.trim();
- let value = text.parse::<u32>().map_err(|_| EINVAL)?;
-
- GenDiskBuilder::validate_block_size(value)?;
- this.data.lock().block_size = value;
- Ok(())
- }
-}
-
-#[vtable]
-impl configfs::AttributeOperations<2> for DeviceConfig {
- type Data = DeviceConfig;
-
- fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
- let mut writer = kernel::str::Formatter::new(page);
-
- if this.data.lock().rotational {
- writer.write_str("1\n")?;
- } else {
- writer.write_str("0\n")?;
- }
-
- Ok(writer.bytes_written())
- }
-
- fn store(this: &DeviceConfig, page: &[u8]) -> Result {
- if this.data.lock().powered {
- return Err(EBUSY);
- }
-
- this.data.lock().rotational = kstrtobool_bytes(page)?;
-
- Ok(())
- }
-}
-
-#[vtable]
-impl configfs::AttributeOperations<3> for DeviceConfig {
- type Data = DeviceConfig;
-
- fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
- let mut writer = kernel::str::Formatter::new(page);
- writer.write_fmt(fmt!("{}\n", this.data.lock().capacity_mib))?;
- Ok(writer.bytes_written())
- }
-
- fn store(this: &DeviceConfig, page: &[u8]) -> Result {
- if this.data.lock().powered {
- return Err(EBUSY);
- }
-
- let text = core::str::from_utf8(page)?.trim();
- let value = text.parse::<u64>().map_err(|_| EINVAL)?;
-
- this.data.lock().capacity_mib = value;
- Ok(())
- }
-}
-
-#[vtable]
-impl configfs::AttributeOperations<4> for DeviceConfig {
- type Data = DeviceConfig;
-
- fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
- let mut writer = kernel::str::Formatter::new(page);
- writer.write_fmt(fmt!("{}\n", this.data.lock().irq_mode))?;
- Ok(writer.bytes_written())
- }
+configfs_simple_field!(DeviceConfig, 1, block_size, u32, check GenDiskBuilder::validate_block_size);
+configfs_simple_bool_field!(DeviceConfig, 2, rotational);
+configfs_simple_field!(DeviceConfig, 3, capacity_mib, u64);
+configfs_simple_field!(DeviceConfig, 4, irq_mode, IRQMode);
- fn store(this: &DeviceConfig, page: &[u8]) -> Result {
- if this.data.lock().powered {
- return Err(EBUSY);
- }
+impl core::str::FromStr for IRQMode {
+ type Err = Error;
- let text = core::str::from_utf8(page)?.trim();
- let value = text.parse::<u8>().map_err(|_| EINVAL)?;
-
- this.data.lock().irq_mode = IRQMode::try_from(value)?;
- Ok(())
+ fn from_str(s: &str) -> Result<Self> {
+ let value: u8 = s.parse().map_err(|_| EINVAL)?;
+ value.try_into()
}
}
diff --git a/drivers/block/rnull/configfs/macros.rs b/drivers/block/rnull/configfs/macros.rs
new file mode 100644
index 0000000000000..53ce9d5dbdc8a
--- /dev/null
+++ b/drivers/block/rnull/configfs/macros.rs
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use super::DeviceConfig;
+use core::{fmt::Write, str::FromStr};
+use kernel::{page::PAGE_SIZE, prelude::*};
+
+pub(crate) fn show_field<T: fmt::Display>(value: T, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+ let mut writer = kernel::str::Formatter::new(page);
+ writer.write_fmt(fmt!("{}\n", value))?;
+ Ok(writer.bytes_written())
+}
+
+pub(crate) fn store_with_power_check<F>(this: &DeviceConfig, page: &[u8], store_fn: F) -> Result
+where
+ F: FnOnce(&DeviceConfig, &[u8]) -> Result,
+{
+ if this.data.lock().powered {
+ return Err(EBUSY);
+ }
+ store_fn(this, page)
+}
+
+pub(crate) fn store_number_with_power_check<F, T>(
+ this: &DeviceConfig,
+ page: &[u8],
+ store_fn: F,
+) -> Result
+where
+ F: FnOnce(&DeviceConfig, T) -> Result,
+ T: FromStr,
+{
+ if this.data.lock().powered {
+ return Err(EBUSY);
+ }
+
+ let text = core::str::from_utf8(page)?.trim();
+ let value = text.parse::<T>().map_err(|_| EINVAL)?;
+
+ store_fn(this, value)
+}
+
+macro_rules! configfs_attribute {
+ (
+ $type:ty,
+ $id:literal,
+ show: |$show_this:ident, $show_page:ident| $show_block:expr,
+ store: |$store_this:ident, $store_page:ident| $store_block:expr
+ $(,)?
+ ) => {
+ #[vtable]
+ impl configfs::AttributeOperations<$id> for $type {
+ type Data = $type;
+
+ fn show($show_this: &$type, $show_page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+ $show_block
+ }
+
+ fn store($store_this: &$type, $store_page: &[u8]) -> Result {
+ $store_block
+ }
+ }
+ };
+}
+pub(crate) use configfs_attribute;
+
+// Specialized macro for simple boolean fields that just store kstrtobool_bytes result.
+macro_rules! configfs_simple_bool_field {
+ ($type:ty, $id:literal, $field:ident) => {
+ crate::configfs::macros::configfs_attribute!($type, $id,
+ show: |this, page| crate::configfs::macros::show_field(this.data.lock().$field, page),
+ store: |this, page|
+ crate::configfs::macros::store_with_power_check(this, page, |this, page| {
+ this.data.lock().$field = kstrtobool_bytes(page)?;
+ Ok(())
+ })
+ );
+ };
+}
+pub(crate) use configfs_simple_bool_field;
+
+// Specialized macro for simple numeric fields that just parse and assign
+macro_rules! configfs_simple_field {
+ // Simple direct assignment
+ ($type:ty, $id:literal, $field:ident, $field_type:ty) => {
+ crate::configfs::macros::configfs_attribute!($type, $id,
+ show: |this, page| crate::configfs::macros::show_field(this.data.lock().$field, page),
+ store: |this, page| crate::configfs::macros::store_number_with_power_check(
+ this,
+ page,
+ |this, value: $field_type| {
+ this.data.lock().$field = value;
+ Ok(())
+ }
+ )
+ );
+ };
+ // With infallible conversion expression (direct value)
+ ($type:ty, $id:literal, $field:ident, $field_type:ty, into $convert:expr) => {
+ crate::configfs::macros::configfs_attribute!($type, $id,
+ show: |this, page|
+ crate::configfs::macros::show_field(this.data.lock().$field, page),
+ store: |this, page| crate::configfs::macros::store_number_with_power_check(
+ this,
+ page,
+ |this, value: $field_type| {
+ this.data.lock().$field = $convert(value);
+ Ok(())
+ }
+ )
+ );
+ };
+ // With check, no conversion
+ ($type:ty, $id:literal, $field:ident, $field_type:ty, check $check:expr) => {
+ crate::configfs::macros::configfs_attribute!($type, $id,
+ show: |this, page| crate::configfs::macros::show_field(this.data.lock().$field, page),
+ store: |this, page| crate::configfs::macros::store_number_with_power_check(
+ this,
+ page,
+ |this, value: $field_type| {
+ $check(value)?;
+ this.data.lock().$field = value;
+ Ok(())
+ }
+ )
+ );
+ };
+}
+pub(crate) use configfs_simple_field;
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 03/79] block: rnull: add macros to define configfs attributes
2026-02-15 23:34 ` [PATCH 03/79] block: rnull: add macros to define configfs attributes Andreas Hindborg
@ 2026-03-16 9:23 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 9:23 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:50AM +0100, Andreas Hindborg wrote:
> Defining configfs attributes in rust is a bit verbose at the moment. Add
> some macros to make the attribute definition less verbose.
>
> The configfs Rust abstractions should eventually provide procedural macros
> for this task. When we get more users of the configfs Rust abstractions, we
> shall consider this task.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> ---
> drivers/block/rnull/configfs.rs | 134 +++++++++------------------------
> drivers/block/rnull/configfs/macros.rs | 128 +++++++++++++++++++++++++++++++
> 2 files changed, 164 insertions(+), 98 deletions(-)
>
> diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
> index ea38b27a9011c..eafa71dfc40d3 100644
> --- a/drivers/block/rnull/configfs.rs
> +++ b/drivers/block/rnull/configfs.rs
> @@ -1,20 +1,41 @@
> // SPDX-License-Identifier: GPL-2.0
>
> -use super::{NullBlkDevice, THIS_MODULE};
> +use super::{
> + NullBlkDevice,
> + THIS_MODULE, //
> +};
> use kernel::{
> - block::mq::gen_disk::{GenDisk, GenDiskBuilder},
> + block::mq::gen_disk::{
> + GenDisk,
> + GenDiskBuilder, //
> + },
> c_str,
> - configfs::{self, AttributeOperations},
> + configfs::{
> + self,
> + AttributeOperations, //
> + },
> configfs_attrs,
> - fmt::{self, Write as _},
> + fmt::{
> + self,
> + Write as _, //
> + },
> new_mutex,
> page::PAGE_SIZE,
> prelude::*,
> - str::{kstrtobool_bytes, CString},
> - sync::Mutex,
> + str::{
> + kstrtobool_bytes,
> + CString, //
> + },
> + sync::Mutex, //
> +};
> +use macros::{
> + configfs_simple_bool_field,
> + configfs_simple_field, //
> };
> use pin_init::PinInit;
>
> +mod macros;
> +
> pub(crate) fn subsystem() -> impl PinInit<kernel::configfs::Subsystem<Config>, Error> {
> let item_type = configfs_attrs! {
> container: configfs::Subsystem<Config>,
> @@ -166,99 +187,16 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> }
> }
>
> -#[vtable]
> -impl configfs::AttributeOperations<1> for DeviceConfig {
> - type Data = DeviceConfig;
> -
> - fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> - let mut writer = kernel::str::Formatter::new(page);
> - writer.write_fmt(fmt!("{}\n", this.data.lock().block_size))?;
> - Ok(writer.bytes_written())
> - }
> -
> - fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> - if this.data.lock().powered {
> - return Err(EBUSY);
> - }
> -
> - let text = core::str::from_utf8(page)?.trim();
> - let value = text.parse::<u32>().map_err(|_| EINVAL)?;
> -
> - GenDiskBuilder::validate_block_size(value)?;
> - this.data.lock().block_size = value;
> - Ok(())
> - }
> -}
> -
> -#[vtable]
> -impl configfs::AttributeOperations<2> for DeviceConfig {
> - type Data = DeviceConfig;
> -
> - fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> - let mut writer = kernel::str::Formatter::new(page);
> -
> - if this.data.lock().rotational {
> - writer.write_str("1\n")?;
> - } else {
> - writer.write_str("0\n")?;
> - }
> -
> - Ok(writer.bytes_written())
> - }
> -
> - fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> - if this.data.lock().powered {
> - return Err(EBUSY);
> - }
> -
> - this.data.lock().rotational = kstrtobool_bytes(page)?;
> -
> - Ok(())
> - }
> -}
> -
> -#[vtable]
> -impl configfs::AttributeOperations<3> for DeviceConfig {
> - type Data = DeviceConfig;
> -
> - fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> - let mut writer = kernel::str::Formatter::new(page);
> - writer.write_fmt(fmt!("{}\n", this.data.lock().capacity_mib))?;
> - Ok(writer.bytes_written())
> - }
> -
> - fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> - if this.data.lock().powered {
> - return Err(EBUSY);
> - }
> -
> - let text = core::str::from_utf8(page)?.trim();
> - let value = text.parse::<u64>().map_err(|_| EINVAL)?;
> -
> - this.data.lock().capacity_mib = value;
> - Ok(())
> - }
> -}
> -
> -#[vtable]
> -impl configfs::AttributeOperations<4> for DeviceConfig {
> - type Data = DeviceConfig;
> -
> - fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> - let mut writer = kernel::str::Formatter::new(page);
> - writer.write_fmt(fmt!("{}\n", this.data.lock().irq_mode))?;
> - Ok(writer.bytes_written())
> - }
> +configfs_simple_field!(DeviceConfig, 1, block_size, u32, check GenDiskBuilder::validate_block_size);
> +configfs_simple_bool_field!(DeviceConfig, 2, rotational);
> +configfs_simple_field!(DeviceConfig, 3, capacity_mib, u64);
> +configfs_simple_field!(DeviceConfig, 4, irq_mode, IRQMode);
>
> - fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> - if this.data.lock().powered {
> - return Err(EBUSY);
> - }
> +impl core::str::FromStr for IRQMode {
> + type Err = Error;
>
> - let text = core::str::from_utf8(page)?.trim();
> - let value = text.parse::<u8>().map_err(|_| EINVAL)?;
> -
> - this.data.lock().irq_mode = IRQMode::try_from(value)?;
> - Ok(())
> + fn from_str(s: &str) -> Result<Self> {
> + let value: u8 = s.parse().map_err(|_| EINVAL)?;
> + value.try_into()
> }
> }
> diff --git a/drivers/block/rnull/configfs/macros.rs b/drivers/block/rnull/configfs/macros.rs
> new file mode 100644
> index 0000000000000..53ce9d5dbdc8a
> --- /dev/null
> +++ b/drivers/block/rnull/configfs/macros.rs
> @@ -0,0 +1,128 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +use super::DeviceConfig;
> +use core::{fmt::Write, str::FromStr};
> +use kernel::{page::PAGE_SIZE, prelude::*};
> +
> +pub(crate) fn show_field<T: fmt::Display>(value: T, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> + let mut writer = kernel::str::Formatter::new(page);
> + writer.write_fmt(fmt!("{}\n", value))?;
> + Ok(writer.bytes_written())
> +}
> +
> +pub(crate) fn store_with_power_check<F>(this: &DeviceConfig, page: &[u8], store_fn: F) -> Result
> +where
> + F: FnOnce(&DeviceConfig, &[u8]) -> Result,
> +{
> + if this.data.lock().powered {
> + return Err(EBUSY);
> + }
> + store_fn(this, page)
> +}
> +
> +pub(crate) fn store_number_with_power_check<F, T>(
> + this: &DeviceConfig,
> + page: &[u8],
> + store_fn: F,
> +) -> Result
> +where
> + F: FnOnce(&DeviceConfig, T) -> Result,
> + T: FromStr,
> +{
> + if this.data.lock().powered {
> + return Err(EBUSY);
> + }
> +
> + let text = core::str::from_utf8(page)?.trim();
> + let value = text.parse::<T>().map_err(|_| EINVAL)?;
> +
> + store_fn(this, value)
> +}
> +
> +macro_rules! configfs_attribute {
> + (
> + $type:ty,
> + $id:literal,
> + show: |$show_this:ident, $show_page:ident| $show_block:expr,
> + store: |$store_this:ident, $store_page:ident| $store_block:expr
> + $(,)?
> + ) => {
> + #[vtable]
> + impl configfs::AttributeOperations<$id> for $type {
> + type Data = $type;
> +
> + fn show($show_this: &$type, $show_page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> + $show_block
> + }
> +
> + fn store($store_this: &$type, $store_page: &[u8]) -> Result {
> + $store_block
> + }
> + }
> + };
> +}
> +pub(crate) use configfs_attribute;
> +
> +// Specialized macro for simple boolean fields that just store kstrtobool_bytes result.
> +macro_rules! configfs_simple_bool_field {
> + ($type:ty, $id:literal, $field:ident) => {
> + crate::configfs::macros::configfs_attribute!($type, $id,
> + show: |this, page| crate::configfs::macros::show_field(this.data.lock().$field, page),
> + store: |this, page|
> + crate::configfs::macros::store_with_power_check(this, page, |this, page| {
> + this.data.lock().$field = kstrtobool_bytes(page)?;
> + Ok(())
> + })
> + );
> + };
> +}
> +pub(crate) use configfs_simple_bool_field;
> +
> +// Specialized macro for simple numeric fields that just parse and assign
> +macro_rules! configfs_simple_field {
> + // Simple direct assignment
> + ($type:ty, $id:literal, $field:ident, $field_type:ty) => {
> + crate::configfs::macros::configfs_attribute!($type, $id,
> + show: |this, page| crate::configfs::macros::show_field(this.data.lock().$field, page),
> + store: |this, page| crate::configfs::macros::store_number_with_power_check(
> + this,
> + page,
> + |this, value: $field_type| {
> + this.data.lock().$field = value;
I think there's a TOCTOU issue here. You take the lock to perform a
power check in store_number_with_power_check(), then you release the
lock and check again in `store`. But `powered` could have changed in the
meantime.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 04/79] block: rust: fix generation of bindings to `BLK_STS_.*`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (2 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 03/79] block: rnull: add macros to define configfs attributes Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 9:27 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned` Andreas Hindborg
` (74 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Bindgen generates constants for CPP integer literals as u32. The
`blk_status_t` type is defined as `u8` but the variants of the type are
defined as integer literals via CPP macros. Thus the defined variants of
the type are not of the same type as the type itself.
Prevent bindgen from emitting generated bindings for the `BLK_STS_.*`
defines and instead define constants manually in `bindings_helper.h`
Also remove casts that are no longer necessary.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/bindgen_parameters | 3 +++
rust/bindings/bindings_helper.h | 19 +++++++++++++++++++
rust/kernel/block/mq/operations.rs | 2 +-
3 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters
index fd2fd1c3cb9a5..0968541c9bc16 100644
--- a/rust/bindgen_parameters
+++ b/rust/bindgen_parameters
@@ -5,6 +5,9 @@
--blocklist-type __kernel_s?size_t
--blocklist-type __kernel_ptrdiff_t
+# These are generated as u32 by bindgen, but should be u8.
+--blocklist-item BLK_STS_.*
+
--opaque-type xregs_state
--opaque-type desc_struct
--opaque-type arch_lbr_state
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index a783106cdac6f..e0ba5c712c560 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -113,6 +113,25 @@ const gfp_t RUST_CONST_HELPER___GFP_ZERO = __GFP_ZERO;
const gfp_t RUST_CONST_HELPER___GFP_HIGHMEM = ___GFP_HIGHMEM;
const gfp_t RUST_CONST_HELPER___GFP_NOWARN = ___GFP_NOWARN;
const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ROTATIONAL = BLK_FEAT_ROTATIONAL;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_OK = BLK_STS_OK;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_NOTSUPP = BLK_STS_NOTSUPP;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_TIMEOUT = BLK_STS_TIMEOUT;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_NOSPC = BLK_STS_NOSPC;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_TRANSPORT = BLK_STS_TRANSPORT;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_TARGET = BLK_STS_TARGET;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_RESV_CONFLICT = BLK_STS_RESV_CONFLICT;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_MEDIUM = BLK_STS_MEDIUM;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_PROTECTION = BLK_STS_PROTECTION;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_RESOURCE = BLK_STS_RESOURCE;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_IOERR = BLK_STS_IOERR;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_DM_REQUEUE = BLK_STS_DM_REQUEUE;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_AGAIN = BLK_STS_AGAIN;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_DEV_RESOURCE = BLK_STS_DEV_RESOURCE;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_ZONE_OPEN_RESOURCE = BLK_STS_ZONE_OPEN_RESOURCE;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_ZONE_ACTIVE_RESOURCE = BLK_STS_ZONE_ACTIVE_RESOURCE;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_OFFLINE = BLK_STS_OFFLINE;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_DURATION_LIMIT = BLK_STS_DURATION_LIMIT;
+const blk_status_t RUST_CONST_HELPER_BLK_STS_INVAL = BLK_STS_INVAL;
const fop_flags_t RUST_CONST_HELPER_FOP_UNSIGNED_OFFSET = FOP_UNSIGNED_OFFSET;
const xa_mark_t RUST_CONST_HELPER_XA_PRESENT = XA_PRESENT;
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 8ad46129a52c4..b68c0208efc66 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -124,7 +124,7 @@ impl<T: Operations> OperationsVTable<T> {
if let Err(e) = ret {
e.to_blk_status()
} else {
- bindings::BLK_STS_OK as bindings::blk_status_t
+ bindings::BLK_STS_OK
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 04/79] block: rust: fix generation of bindings to `BLK_STS_.*`
2026-02-15 23:34 ` [PATCH 04/79] block: rust: fix generation of bindings to `BLK_STS_.*` Andreas Hindborg
@ 2026-03-16 9:27 ` Alice Ryhl
2026-03-16 11:58 ` Alice Ryhl
0 siblings, 1 reply; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 9:27 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:51AM +0100, Andreas Hindborg wrote:
> Bindgen generates constants for CPP integer literals as u32. The
> `blk_status_t` type is defined as `u8` but the variants of the type are
> defined as integer literals via CPP macros. Thus the defined variants of
> the type are not of the same type as the type itself.
>
> Prevent bindgen from emitting generated bindings for the `BLK_STS_.*`
> defines and instead define constants manually in `bindings_helper.h`
>
> Also remove casts that are no longer necessary.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
It'd be ideal to change the C header to use an enum, but that may not
work as I'm not sure you can specify the integer width you want for an
enum.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply [flat|nested] 114+ messages in thread
* Re: [PATCH 04/79] block: rust: fix generation of bindings to `BLK_STS_.*`
2026-03-16 9:27 ` Alice Ryhl
@ 2026-03-16 11:58 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 11:58 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Mar 16, 2026 at 10:27 AM Alice Ryhl <aliceryhl@google.com> wrote:
>
> On Mon, Feb 16, 2026 at 12:34:51AM +0100, Andreas Hindborg wrote:
> > Bindgen generates constants for CPP integer literals as u32. The
> > `blk_status_t` type is defined as `u8` but the variants of the type are
> > defined as integer literals via CPP macros. Thus the defined variants of
> > the type are not of the same type as the type itself.
> >
> > Prevent bindgen from emitting generated bindings for the `BLK_STS_.*`
> > defines and instead define constants manually in `bindings_helper.h`
> >
> > Also remove casts that are no longer necessary.
> >
> > Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>
> It'd be ideal to change the C header to use an enum, but that may not
> work as I'm not sure you can specify the integer width you want for an
> enum.
>
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Honestly, it might be better just to declare a Rust module somewhere
with each constant redeclared:
const BLK_STS_FOO: blk_status_t = bindings::BLK_STS_FOO as blk_status_t;
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (3 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 04/79] block: rust: fix generation of bindings to `BLK_STS_.*` Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 10:01 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 06/79] block: rust: add `Request` private data support Andreas Hindborg
` (73 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Simplify the reference counting scheme for `Request` from 4 states to 3
states. This is achieved by coalescing the zero state between block layer
owned and uniquely owned by driver.
Implement `Ownable` for `Request` and deliver `Request` to drivers as
`Owned<Request>`. In this process:
- Move uniqueness assertions out of `rnull` as these are now guaranteed by
the `Owned` type.
- Move `start_unchecked`, `try_set_end` and `end_ok` from `Request` to
`Owned<Request>`, relying on type invariant for uniqueness.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 26 ++---
rust/kernel/block/mq.rs | 10 +-
rust/kernel/block/mq/operations.rs | 27 +++--
rust/kernel/block/mq/request.rs | 218 +++++++++++++++++++++----------------
4 files changed, 158 insertions(+), 123 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index bd883a5061cab..6a7f660d31998 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -19,7 +19,8 @@
},
},
error::Result,
- new_mutex, pr_info,
+ new_mutex,
+ pr_info,
prelude::*,
str::CString,
sync::{
@@ -27,6 +28,10 @@
Arc,
Mutex, //
},
+ types::{
+ OwnableRefCounted,
+ Owned, //
+ }, //
};
use pin_init::PinInit;
@@ -131,15 +136,10 @@ impl Operations for NullBlkDevice {
type QueueData = KBox<QueueData>;
#[inline(always)]
- fn queue_rq(queue_data: &QueueData, rq: ARef<mq::Request<Self>>, _is_last: bool) -> Result {
+ fn queue_rq(queue_data: &QueueData, rq: Owned<mq::Request<Self>>, _is_last: bool) -> Result {
match queue_data.irq_mode {
- IRQMode::None => mq::Request::end_ok(rq)
- .map_err(|_e| kernel::error::code::EIO)
- // We take no refcounts on the request, so we expect to be able to
- // end the request. The request reference must be unique at this
- // point, and so `end_ok` cannot fail.
- .expect("Fatal error - expected to be able to end request"),
- IRQMode::Soft => mq::Request::complete(rq),
+ IRQMode::None => rq.end_ok(),
+ IRQMode::Soft => mq::Request::complete(rq.into()),
}
Ok(())
}
@@ -147,11 +147,9 @@ fn queue_rq(queue_data: &QueueData, rq: ARef<mq::Request<Self>>, _is_last: bool)
fn commit_rqs(_queue_data: &QueueData) {}
fn complete(rq: ARef<mq::Request<Self>>) {
- mq::Request::end_ok(rq)
+ OwnableRefCounted::try_from_shared(rq)
.map_err(|_e| kernel::error::code::EIO)
- // We take no refcounts on the request, so we expect to be able to
- // end the request. The request reference must be unique at this
- // point, and so `end_ok` cannot fail.
- .expect("Fatal error - expected to be able to end request");
+ .expect("Failed to complete request")
+ .end_ok();
}
}
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 1fd0d54dd5493..b8ecd69abe980 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -62,6 +62,7 @@
//! new_mutex,
//! prelude::*,
//! sync::{aref::ARef, Arc, Mutex},
+//! types::{ForeignOwnable, OwnableRefCounted, Owned},
//! };
//!
//! struct MyBlkDevice;
@@ -70,17 +71,18 @@
//! impl Operations for MyBlkDevice {
//! type QueueData = ();
//!
-//! fn queue_rq(_queue_data: (), rq: ARef<Request<Self>>, _is_last: bool) -> Result {
-//! Request::end_ok(rq);
+//! fn queue_rq(_queue_data: (), rq: Owned<Request<Self>>, _is_last: bool) -> Result {
+//! rq.end_ok();
//! Ok(())
//! }
//!
//! fn commit_rqs(_queue_data: ()) {}
//!
//! fn complete(rq: ARef<Request<Self>>) {
-//! Request::end_ok(rq)
+//! OwnableRefCounted::try_from_shared(rq)
//! .map_err(|_e| kernel::error::code::EIO)
-//! .expect("Fatal error - expected to be able to end request");
+//! .expect("Fatal error - expected to be able to end request")
+//! .end_ok();
//! }
//! }
//!
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index b68c0208efc66..3dea79d647ff7 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -9,10 +9,10 @@
block::mq::{request::RequestDataWrapper, Request},
error::{from_result, Result},
prelude::*,
- sync::{aref::ARef, Refcount},
- types::ForeignOwnable,
+ sync::{aref::ARef, atomic::ordering, Refcount},
+ types::{ForeignOwnable, Owned},
};
-use core::marker::PhantomData;
+use core::{marker::PhantomData, ptr::NonNull};
type ForeignBorrowed<'a, T> = <T as ForeignOwnable>::Borrowed<'a>;
@@ -36,7 +36,7 @@ pub trait Operations: Sized {
/// `false`, the driver is allowed to defer committing the request.
fn queue_rq(
queue_data: ForeignBorrowed<'_, Self::QueueData>,
- rq: ARef<Request<Self>>,
+ rq: Owned<Request<Self>>,
is_last: bool,
) -> Result;
@@ -90,16 +90,23 @@ impl<T: Operations> OperationsVTable<T> {
// this function.
let request = unsafe { &*(*bd).rq.cast::<Request<T>>() };
- // One refcount for the ARef, one for being in flight
- request.wrapper_ref().refcount().set(2);
+ debug_assert!(
+ request
+ .wrapper_ref()
+ .refcount()
+ .as_atomic()
+ .load(ordering::Acquire)
+ == 0
+ );
// SAFETY:
- // - We own a refcount that we took above. We pass that to `ARef`.
+ // - By API contract, we own the request.
// - By the safety requirements of this function, `request` is a valid
// `struct request` and the private data is properly initialized.
// - `rq` will be alive until `blk_mq_end_request` is called and is
- // reference counted by `ARef` until then.
- let rq = unsafe { Request::aref_from_raw((*bd).rq) };
+ // reference counted by until then.
+ let mut rq =
+ unsafe { Owned::from_raw(NonNull::<Request<T>>::new_unchecked((*bd).rq.cast())) };
// SAFETY: `hctx` is valid as required by this function.
let queue_data = unsafe { (*(*hctx).queue).queuedata };
@@ -111,7 +118,7 @@ impl<T: Operations> OperationsVTable<T> {
let queue_data = unsafe { T::QueueData::borrow(queue_data) };
// SAFETY: We have exclusive access and we just set the refcount above.
- unsafe { Request::start_unchecked(&rq) };
+ unsafe { rq.start_unchecked() };
let ret = T::queue_rq(
queue_data,
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index cf013b9e2cacf..148348b4ef245 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -7,13 +7,12 @@
use crate::{
bindings,
block::mq::Operations,
- error::Result,
sync::{
- aref::{ARef, AlwaysRefCounted, RefCounted},
- atomic::Relaxed,
+ aref::{ARef, RefCounted},
+ atomic::ordering,
Refcount,
},
- types::Opaque,
+ types::{Opaque, Ownable, OwnableRefCounted, Owned},
};
use core::{marker::PhantomData, ptr::NonNull};
@@ -21,25 +20,21 @@
///
/// # Implementation details
///
-/// There are four states for a request that the Rust bindings care about:
+/// There are three states for a request that the Rust bindings care about:
///
-/// 1. Request is owned by block layer (refcount 0).
-/// 2. Request is owned by driver but with zero [`ARef`]s in existence
-/// (refcount 1).
-/// 3. Request is owned by driver with exactly one [`ARef`] in existence
-/// (refcount 2).
-/// 4. Request is owned by driver with more than one [`ARef`] in existence
-/// (refcount > 2).
+/// - 0: The request is owned by C block layer or is uniquely referenced (by [`Owned<_>`]).
+/// - 1: The request is owned by Rust abstractions but is not referenced.
+/// - 2+: There is one or more [`ARef`] instances referencing the request.
///
+/// We need to track 1 and 2 to make sure that `tag_to_rq` does not issue any
+/// [`ARef`] to requests not owned by the driver, or to requests that have a
+/// [`Owned`] referencing it.
///
-/// We need to track 1 and 2 to ensure we fail tag to request conversions for
-/// requests that are not owned by the driver.
-///
-/// We need to track 3 and 4 to ensure that it is safe to end the request and hand
-/// back ownership to the block layer.
+/// We need to track 3 to know when it is safe to convert an [`ARef`] to a
+/// [`Owned`].
///
/// Note that the driver can still obtain new `ARef` even if there is no `ARef`s in existence by
-/// using `tag_to_rq`, hence the need to distinguish B and C.
+/// using `tag_to_rq`, hence the need to distinct 1 and 2.
///
/// The states are tracked through the private `refcount` field of
/// `RequestDataWrapper`. This structure lives in the private data area of the C
@@ -66,6 +61,7 @@ impl<T: Operations> Request<T> {
///
/// * The caller must own a refcount on `ptr` that is transferred to the
/// returned [`ARef`].
+ /// * The refcount must be >= 2.
/// * The type invariants for [`Request`] must hold for the pointee of `ptr`.
///
/// [`struct request`]: srctree/include/linux/blk-mq.h
@@ -76,72 +72,6 @@ pub(crate) unsafe fn aref_from_raw(ptr: *mut bindings::request) -> ARef<Self> {
unsafe { ARef::from_raw(NonNull::new_unchecked(ptr.cast())) }
}
- /// Notify the block layer that a request is going to be processed now.
- ///
- /// The block layer uses this hook to do proper initializations such as
- /// starting the timeout timer. It is a requirement that block device
- /// drivers call this function when starting to process a request.
- ///
- /// # Safety
- ///
- /// The caller must have exclusive ownership of `self`, that is
- /// `self.wrapper_ref().refcount() == 2`.
- pub(crate) unsafe fn start_unchecked(this: &ARef<Self>) {
- // SAFETY: By type invariant, `self.0` is a valid `struct request` and
- // we have exclusive access.
- unsafe { bindings::blk_mq_start_request(this.0.get()) };
- }
-
- /// Try to take exclusive ownership of `this` by dropping the refcount to 0.
- /// This fails if `this` is not the only [`ARef`] pointing to the underlying
- /// [`Request`].
- ///
- /// If the operation is successful, [`Ok`] is returned with a pointer to the
- /// C [`struct request`]. If the operation fails, `this` is returned in the
- /// [`Err`] variant.
- ///
- /// [`struct request`]: srctree/include/linux/blk-mq.h
- fn try_set_end(this: ARef<Self>) -> Result<*mut bindings::request, ARef<Self>> {
- // To hand back the ownership, we need the current refcount to be 2.
- // Since we can race with `TagSet::tag_to_rq`, this needs to atomically reduce
- // refcount to 0. `Refcount` does not provide a way to do this, so use the underlying
- // atomics directly.
- if let Err(_old) = this
- .wrapper_ref()
- .refcount()
- .as_atomic()
- .cmpxchg(2, 0, Relaxed)
- {
- return Err(this);
- }
-
- let request_ptr = this.0.get();
- core::mem::forget(this);
-
- Ok(request_ptr)
- }
-
- /// Notify the block layer that the request has been completed without errors.
- ///
- /// This function will return [`Err`] if `this` is not the only [`ARef`]
- /// referencing the request.
- pub fn end_ok(this: ARef<Self>) -> Result<(), ARef<Self>> {
- let request_ptr = Self::try_set_end(this)?;
-
- // SAFETY: By type invariant, `this.0` was a valid `struct request`. The
- // success of the call to `try_set_end` guarantees that there are no
- // `ARef`s pointing to this request. Therefore it is safe to hand it
- // back to the block layer.
- unsafe {
- bindings::blk_mq_end_request(
- request_ptr,
- bindings::BLK_STS_OK as bindings::blk_status_t,
- )
- };
-
- Ok(())
- }
-
/// Complete the request by scheduling `Operations::complete` for
/// execution.
///
@@ -234,27 +164,125 @@ unsafe impl<T: Operations> Sync for Request<T> {}
// matching reference count decrement is executed.
unsafe impl<T: Operations> RefCounted for Request<T> {
fn inc_ref(&self) {
- self.wrapper_ref().refcount().inc();
+ let refcount = &self.wrapper_ref().refcount().as_atomic();
+
+ // Load acquire, store relaxed. We sync with store release of
+ // `OwnableRefCounted::into_shared`. After that all unique references are dead and we have
+ // shared access. We can use relaxed ordering for the store.
+ #[cfg_attr(not(debug_assertions), allow(unused_variables))]
+ let old = refcount.fetch_add(1, ordering::Acquire);
+
+ debug_assert!(old >= 1, "Request refcount zero clone");
}
unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
- // SAFETY: The type invariants of `ARef` guarantee that `obj` is valid
+ // SAFETY: The type invariants of `RefCounted` guarantee that `obj` is valid
// for read.
let wrapper_ptr = unsafe { Self::wrapper_ptr(obj.as_ptr()).as_ptr() };
// SAFETY: The type invariant of `Request` guarantees that the private
// data area is initialized and valid.
let refcount = unsafe { &*RequestDataWrapper::refcount_ptr(wrapper_ptr) };
- #[cfg_attr(not(CONFIG_DEBUG_MISC), allow(unused_variables))]
- let is_zero = refcount.dec_and_test();
+ // Store release to sync with load acquire in
+ // `OwnableRefCounted::try_from_shared`.
+ #[cfg_attr(not(debug_assertions), allow(unused_variables))]
+ let old = refcount.as_atomic().fetch_sub(1, ordering::Release);
- #[cfg(CONFIG_DEBUG_MISC)]
- if is_zero {
- panic!("Request reached refcount zero in Rust abstractions");
- }
+ debug_assert!(
+ old > 1,
+ "Request reached refcount zero in Rust abstractions"
+ );
+ }
+}
+
+impl<T: Operations> Owned<Request<T>> {
+ /// Notify the block layer that a request is going to be processed now.
+ ///
+ /// The block layer uses this hook to do proper initializations such as
+ /// starting the timeout timer. It is a requirement that block device
+ /// drivers call this function when starting to process a request.
+ ///
+ /// # Safety
+ ///
+ /// The caller must have exclusive ownership of `self`, that is
+ /// `self.wrapper_ref().refcount() == 0`.
+ ///
+ /// This can only be called once in the request life cycle.
+ pub(crate) unsafe fn start_unchecked(&mut self) {
+ // SAFETY: By type invariant, `self.0` is a valid `struct request` and
+ // we have exclusive access.
+ unsafe { bindings::blk_mq_start_request(self.0.get()) };
+ }
+
+ /// Notify the block layer that the request has been completed without errors.
+ pub fn end_ok(self) {
+ let request_ptr = self.0.get().cast();
+ core::mem::forget(self);
+ // SAFETY: By type invariant, `this.0` was a valid `struct request`. The
+ // existence of `self` guarantees that there are no `ARef`s pointing to
+ // this request. Therefore it is safe to hand it back to the block
+ // layer.
+ unsafe { bindings::blk_mq_end_request(request_ptr, bindings::BLK_STS_OK) };
+ }
+}
+
+// SAFETY: The `release` implementation frees the underlying request according to the reference
+// counting scheme for `Request`.
+unsafe impl<T: Operations> Ownable for Request<T> {
+ unsafe fn release(this: NonNull<Self>) {
+ // SAFETY: The safety requirements of this function guarantee that `this`
+ // is valid for read.
+ let wrapper_ptr = unsafe { Self::wrapper_ptr(this.as_ptr()).as_ptr() };
+ // SAFETY: The type invariant of `Request` guarantees that the private
+ // data area is initialized and valid.
+ let refcount = unsafe { &*RequestDataWrapper::refcount_ptr(wrapper_ptr) };
+
+ // Store release to sync with load acquire when converting back to owned.
+ #[cfg_attr(not(debug_assertions), allow(unused_variables))]
+ let old = refcount.as_atomic().fetch_add(1, ordering::Release);
+
+ debug_assert!(
+ old == 0,
+ "Invalid refcount when releasing `Owned<Request<T>>`"
+ );
}
}
-// SAFETY: We currently do not implement `Ownable`, thus it is okay to obtain an `ARef<Request>`
-// from a `&Request` (but this will change in the future).
-unsafe impl<T: Operations> AlwaysRefCounted for Request<T> {}
+impl<T: Operations> OwnableRefCounted for Request<T> {
+ fn try_from_shared(this: ARef<Self>) -> core::result::Result<Owned<Self>, ARef<Self>> {
+ // Load acquire to sync with decrement store release to make sure all
+ // shared access has ended.
+ let updated = this
+ .wrapper_ref()
+ .refcount()
+ .as_atomic()
+ .cmpxchg(2, 0, ordering::Acquire);
+
+ match updated {
+ Ok(_) => Ok(
+ // SAFETY: We achieved unique ownership above.
+ unsafe { Owned::from_raw(ARef::into_raw(this)) },
+ ),
+ Err(_) => Err(this),
+ }
+ }
+
+ fn into_shared(this: Owned<Self>) -> ARef<Self> {
+ // Store release to sync with future increments using load acquire to
+ // make sure exclusive access has ended before shared access start.
+ #[cfg_attr(not(debug_assertions), allow(unused_variables))]
+ let old = this
+ .wrapper_ref()
+ .refcount()
+ .as_atomic()
+ .fetch_add(2, ordering::Release);
+
+ debug_assert!(
+ old == 0,
+ "Invalid refcount when upgrading `Owned<Request<T>>`"
+ );
+
+ // SAFETY: We incremented the refcount above.
+ unsafe { ARef::from_raw(Owned::into_raw(this)) }
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned`
2026-02-15 23:34 ` [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned` Andreas Hindborg
@ 2026-03-16 10:01 ` Alice Ryhl
2026-03-23 12:08 ` Andreas Hindborg
0 siblings, 1 reply; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:01 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:52AM +0100, Andreas Hindborg wrote:
> Simplify the reference counting scheme for `Request` from 4 states to 3
> states. This is achieved by coalescing the zero state between block layer
> owned and uniquely owned by driver.
>
> Implement `Ownable` for `Request` and deliver `Request` to drivers as
> `Owned<Request>`. In this process:
>
> - Move uniqueness assertions out of `rnull` as these are now guaranteed by
> the `Owned` type.
> - Move `start_unchecked`, `try_set_end` and `end_ok` from `Request` to
> `Owned<Request>`, relying on type invariant for uniqueness.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
It would be a lot cleaner if we could implement HrTimerPointer for
Owned<Request> and entirely get rid of the refcount in request so we
don't need ARef<Request> at all.
Is there a reason we *need* ARef here?
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* Re: [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned`
2026-03-16 10:01 ` Alice Ryhl
@ 2026-03-23 12:08 ` Andreas Hindborg
2026-03-24 13:27 ` Alice Ryhl
0 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-03-23 12:08 UTC (permalink / raw)
To: Alice Ryhl
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
Alice Ryhl <aliceryhl@google.com> writes:
> On Mon, Feb 16, 2026 at 12:34:52AM +0100, Andreas Hindborg wrote:
>> Simplify the reference counting scheme for `Request` from 4 states to 3
>> states. This is achieved by coalescing the zero state between block layer
>> owned and uniquely owned by driver.
>>
>> Implement `Ownable` for `Request` and deliver `Request` to drivers as
>> `Owned<Request>`. In this process:
>>
>> - Move uniqueness assertions out of `rnull` as these are now guaranteed by
>> the `Owned` type.
>> - Move `start_unchecked`, `try_set_end` and `end_ok` from `Request` to
>> `Owned<Request>`, relying on type invariant for uniqueness.
>>
>> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>
> It would be a lot cleaner if we could implement HrTimerPointer for
> Owned<Request> and entirely get rid of the refcount in request so we
> don't need ARef<Request> at all.
>
> Is there a reason we *need* ARef here?
There is. Real drivers will need to dma map the data buffers in
`Request` to a device. This requires taking a reference on the pages to
be mapped, which in turn requires taking a reference on the `Request`.
We could split up the reference counts into multiple fields, but that
would be less efficient.
Best regards,
Andreas Hindborg
^ permalink raw reply [flat|nested] 114+ messages in thread
* Re: [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned`
2026-03-23 12:08 ` Andreas Hindborg
@ 2026-03-24 13:27 ` Alice Ryhl
2026-04-08 11:54 ` Andreas Hindborg
0 siblings, 1 reply; 114+ messages in thread
From: Alice Ryhl @ 2026-03-24 13:27 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Mar 23, 2026 at 1:08 PM Andreas Hindborg <a.hindborg@kernel.org> wrote:
>
> Alice Ryhl <aliceryhl@google.com> writes:
>
> > On Mon, Feb 16, 2026 at 12:34:52AM +0100, Andreas Hindborg wrote:
> >> Simplify the reference counting scheme for `Request` from 4 states to 3
> >> states. This is achieved by coalescing the zero state between block layer
> >> owned and uniquely owned by driver.
> >>
> >> Implement `Ownable` for `Request` and deliver `Request` to drivers as
> >> `Owned<Request>`. In this process:
> >>
> >> - Move uniqueness assertions out of `rnull` as these are now guaranteed by
> >> the `Owned` type.
> >> - Move `start_unchecked`, `try_set_end` and `end_ok` from `Request` to
> >> `Owned<Request>`, relying on type invariant for uniqueness.
> >>
> >> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> >
> > It would be a lot cleaner if we could implement HrTimerPointer for
> > Owned<Request> and entirely get rid of the refcount in request so we
> > don't need ARef<Request> at all.
> >
> > Is there a reason we *need* ARef here?
>
> There is. Real drivers will need to dma map the data buffers in
> `Request` to a device. This requires taking a reference on the pages to
> be mapped, which in turn requires taking a reference on the `Request`.
>
> We could split up the reference counts into multiple fields, but that
> would be less efficient.
So how exactly is the refcount used here? Can you elaborate?
With regards to the Owned series, I still think we should split it up
so that the patches making ARef+Owned work like Arc/UniqueArc is
separate follow-up series.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* Re: [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned`
2026-03-24 13:27 ` Alice Ryhl
@ 2026-04-08 11:54 ` Andreas Hindborg
0 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-04-08 11:54 UTC (permalink / raw)
To: Alice Ryhl
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
Alice Ryhl <aliceryhl@google.com> writes:
> On Mon, Mar 23, 2026 at 1:08 PM Andreas Hindborg <a.hindborg@kernel.org> wrote:
>>
>> Alice Ryhl <aliceryhl@google.com> writes:
>>
>> > On Mon, Feb 16, 2026 at 12:34:52AM +0100, Andreas Hindborg wrote:
>> >> Simplify the reference counting scheme for `Request` from 4 states to 3
>> >> states. This is achieved by coalescing the zero state between block layer
>> >> owned and uniquely owned by driver.
>> >>
>> >> Implement `Ownable` for `Request` and deliver `Request` to drivers as
>> >> `Owned<Request>`. In this process:
>> >>
>> >> - Move uniqueness assertions out of `rnull` as these are now guaranteed by
>> >> the `Owned` type.
>> >> - Move `start_unchecked`, `try_set_end` and `end_ok` from `Request` to
>> >> `Owned<Request>`, relying on type invariant for uniqueness.
>> >>
>> >> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>> >
>> > It would be a lot cleaner if we could implement HrTimerPointer for
>> > Owned<Request> and entirely get rid of the refcount in request so we
>> > don't need ARef<Request> at all.
>> >
>> > Is there a reason we *need* ARef here?
>>
>> There is. Real drivers will need to dma map the data buffers in
>> `Request` to a device. This requires taking a reference on the pages to
>> be mapped, which in turn requires taking a reference on the `Request`.
>>
>> We could split up the reference counts into multiple fields, but that
>> would be less efficient.
>
> So how exactly is the refcount used here? Can you elaborate?
I can try to be more clear.
`Request` objects are created when a driver initializes a device. A
driver initializes a number `Request` equal to the queue depth the
driver supports. That is, if a driver/device supports 16 in-flight
requests, the driver allocates and initializes 16 `Request` objects up
front.
When the kernel wants to issue IO to a block device, it finds an idle
`Request` object and sets it up for the IO operation. Then:
1. The block layer hands off the request to the driver. Ownership of the
request is transferred to the driver. At this point, the driver has a
unique reference to the request (`Owned<Request>`).
2. The driver DMA maps the pages of the request. We have to make sure
the request is not handed back to the block layer while the pages are
mapped. To this end, we take a refcount on the request. The reference
that the driver holds is no longer unique (`ARef<Request>`).
3. The driver instructs a device to carry out the request. The driver
releases its refcount on the request and the device takes a refcount.
4. When the device finishes processing the request, ownership is
transferred back to the driver. The device releases it's refcount and
the driver takes a refcount.
5. DMA mappings are torn down. The refcount associated with the DMA
mappings is released.
6. The driver transfers ownership of the request back to the block
layer. To do this, the request must be uniquely owned by the driver.
When the device is done processing a request and we have to transfer
ownership of the request back to the driver, we use an API function
called `tag_to_rq`. This function takes an integer tag and may return a
request reference. For this function to be safe, we have to be able to
assert that the integer tag passed to the function is naming a request
object that it is valid to obtain a reference to. It is not sound to
create references to requests that are not currently in flight. Thus, we
must be able to know this information. The current implementation relies
on the refcount to discover this information:
/// There are three states for a request that the Rust bindings care about:
///
/// - 0: The request is owned by C block layer or is uniquely referenced (by [`Owned<_>`]).
/// - 1: The request is owned by Rust abstractions but is not referenced.
/// - 2+: There is one or more [`ARef`] instances referencing the request.
So, we are using 1 refcount field to encode all the information we need.
Further, in the current implementation, for step 3, the device does not
actually take a refcount on the request. If a driver drops all
references to a request, the refcount lands on 1. We use this to
indicate that the request has been leaked and to know that `tag_to_rq`
is safe. In a situation where the request is DMA mapped, the refcount
would be 2 while the device is processing the request.
Here is a sequence diagram of the flow:
Block Layer Driver Device
─────────── ────── ──────
| | |
| | |
(1) | hand off request | |
|-------------------->| |
| | Owned<Request> |
| | refcount = 0 |
| | |
| | |
(2) | DMA map pages |
| |---------. |
| | into_shared() |
| | ARef<Request> |
| | refcount = 2 |
| | map_pages() |
| | refcount = 3 |
| | |
| | |
(3) | submit to device |
| |--------------------->|
| | (drop driver ref) |
| | refcount = 2 |
| | (DMA ref remains) |
| | |
| | |
| | .----------------. |
| | | Device does | |
| | | DMA to/from | |
| | | mapped pages | |
| | '----------------' |
| | |
| | |
(4) | completion IRQ |
| |<---------------------|
| | refcount = 2 |
| | tag_to_rq(tag) |
| | ARef<Request> |
| | refcount = 3 |
| | |
| | |
(5) | tear down DMA mappings |
| |---------. |
| | (drop DMA ref) |
| | refcount = 2 |
| | |
| | |
(6) | hand back request | |
|<--------------------| |
| | try_from_shared() |
| | cmpxchg(2 -> 0) |
| | Owned<Request> |
| | refcount = 0 |
| | end_ok() |
| | |
We might be able to get by without shared references (`ARef<Request>`)
and only use an owned reference (`Owned<Request>`) if we add additional
fields to the `Reqeuest` structure. We need to track if the request is
in a state where we can return an `Owned<Requst>` from `tag_to_rq` , and
we need to track if any of the pages of the request are mapped for DMA,
so that we can end the request.
I am not convinced that having the additional fields is worth it for
simplifying the reference counting scheme.
> With regards to the Owned series, I still think we should split it up
> so that the patches making ARef+Owned work like Arc/UniqueArc is
> separate follow-up series.
I'll take that into consideration when sending the next spin of that series.
Best regards,
Andreas Hindborg
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 06/79] block: rust: add `Request` private data support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (4 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 05/79] block: rust: change `queue_rq` request type to `Owned` Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 10:10 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 07/79] block: rust: allow `hrtimer::Timer` in `RequestData` Andreas Hindborg
` (72 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
C block device drivers can attach private data to a `struct request`. This
data is stored next to the request structure and is part of the request
allocation set up during driver initialization.
Expose this private request data area to Rust block device drivers.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 5 +++++
rust/kernel/block/mq.rs | 6 ++++++
rust/kernel/block/mq/operations.rs | 24 +++++++++++++++++++++++-
rust/kernel/block/mq/request.rs | 24 +++++++++++++++++++-----
rust/kernel/block/mq/tag_set.rs | 2 +-
5 files changed, 54 insertions(+), 7 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 6a7f660d31998..065639fc4f941 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -134,6 +134,11 @@ struct QueueData {
#[vtable]
impl Operations for NullBlkDevice {
type QueueData = KBox<QueueData>;
+ type RequestData = ();
+
+ fn new_request_data() -> impl PinInit<Self::RequestData> {
+ pin_init::zeroed::<Self::RequestData>()
+ }
#[inline(always)]
fn queue_rq(queue_data: &QueueData, rq: Owned<mq::Request<Self>>, _is_last: bool) -> Result {
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index b8ecd69abe980..a285b753ada88 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -69,8 +69,14 @@
//!
//! #[vtable]
//! impl Operations for MyBlkDevice {
+//! type RequestData = ();
//! type QueueData = ();
//!
+//! fn new_request_data(
+//! ) -> impl PinInit<()> {
+//! pin_init::zeroed::<()>()
+//! }
+//!
//! fn queue_rq(_queue_data: (), rq: Owned<Request<Self>>, _is_last: bool) -> Result {
//! rq.end_ok();
//! Ok(())
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 3dea79d647ff7..cd37b939bbf30 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -13,6 +13,7 @@
types::{ForeignOwnable, Owned},
};
use core::{marker::PhantomData, ptr::NonNull};
+use pin_init::PinInit;
type ForeignBorrowed<'a, T> = <T as ForeignOwnable>::Borrowed<'a>;
@@ -28,10 +29,24 @@
/// [module level documentation]: kernel::block::mq
#[macros::vtable]
pub trait Operations: Sized {
+ /// Data associated with a request. This data is located next to the request
+ /// structure.
+ ///
+ /// To be able to handle accessing this data from interrupt context, this
+ /// data must be `Sync`.
+ ///
+ /// The `RequestData` object is initialized when the requests are allocated
+ /// during queue initialization, and it is are dropped when the requests are
+ /// dropped during queue teardown.
+ type RequestData: Sized + Sync;
+
/// Data associated with the `struct request_queue` that is allocated for
/// the `GenDisk` associated with this `Operations` implementation.
type QueueData: ForeignOwnable;
+ /// Called by the kernel to get an initializer for a `Pin<&mut RequestData>`.
+ fn new_request_data() -> impl PinInit<Self::RequestData>;
+
/// Called by the kernel to queue a request with the driver. If `is_last` is
/// `false`, the driver is allowed to defer committing the request.
fn queue_rq(
@@ -236,6 +251,13 @@ impl<T: Operations> OperationsVTable<T> {
// it is valid for writes.
unsafe { RequestDataWrapper::refcount_ptr(pdu.as_ptr()).write(Refcount::new(0)) };
+ let initializer = T::new_request_data();
+
+ // SAFETY: `pdu` is a valid pointer as established above. We do not
+ // touch `pdu` if `__pinned_init` returns an error. We promise ot to
+ // move the pointee of `pdu`.
+ unsafe { initializer.__pinned_init(RequestDataWrapper::data_ptr(pdu.as_ptr()))? };
+
Ok(0)
})
}
@@ -255,7 +277,7 @@ impl<T: Operations> OperationsVTable<T> {
) {
// SAFETY: The tagset invariants guarantee that all requests are allocated with extra memory
// for the request data.
- let pdu = unsafe { bindings::blk_mq_rq_to_pdu(rq) }.cast::<RequestDataWrapper>();
+ let pdu = unsafe { bindings::blk_mq_rq_to_pdu(rq) }.cast::<RequestDataWrapper<T>>();
// SAFETY: `pdu` is valid for read and write and is properly initialised.
unsafe { core::ptr::drop_in_place(pdu) };
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 148348b4ef245..8a6c29ac627ee 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -96,12 +96,12 @@ pub fn complete(this: ARef<Self>) {
///
/// - `this` must point to a valid allocation of size at least size of
/// [`Self`] plus size of [`RequestDataWrapper`].
- pub(crate) unsafe fn wrapper_ptr(this: *mut Self) -> NonNull<RequestDataWrapper> {
+ pub(crate) unsafe fn wrapper_ptr(this: *mut Self) -> NonNull<RequestDataWrapper<T>> {
let request_ptr = this.cast::<bindings::request>();
// SAFETY: By safety requirements for this function, `this` is a
// valid allocation.
let wrapper_ptr =
- unsafe { bindings::blk_mq_rq_to_pdu(request_ptr).cast::<RequestDataWrapper>() };
+ unsafe { bindings::blk_mq_rq_to_pdu(request_ptr).cast::<RequestDataWrapper<T>>() };
// SAFETY: By C API contract, `wrapper_ptr` points to a valid allocation
// and is not null.
unsafe { NonNull::new_unchecked(wrapper_ptr) }
@@ -109,7 +109,7 @@ pub(crate) unsafe fn wrapper_ptr(this: *mut Self) -> NonNull<RequestDataWrapper>
/// Return a reference to the [`RequestDataWrapper`] stored in the private
/// area of the request structure.
- pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper {
+ pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper<T> {
// SAFETY: By type invariant, `self.0` is a valid allocation. Further,
// the private data associated with this request is initialized and
// valid. The existence of `&self` guarantees that the private data is
@@ -121,16 +121,19 @@ pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper {
/// A wrapper around data stored in the private area of the C [`struct request`].
///
/// [`struct request`]: srctree/include/linux/blk-mq.h
-pub(crate) struct RequestDataWrapper {
+pub(crate) struct RequestDataWrapper<T: Operations> {
/// The Rust request refcount has the following states:
///
/// - 0: The request is owned by C block layer.
/// - 1: The request is owned by Rust abstractions but there are no [`ARef`] references to it.
/// - 2+: There are [`ARef`] references to the request.
refcount: Refcount,
+
+ /// Driver managed request data
+ data: T::RequestData,
}
-impl RequestDataWrapper {
+impl<T: Operations> RequestDataWrapper<T> {
/// Return a reference to the refcount of the request that is embedding
/// `self`.
pub(crate) fn refcount(&self) -> &Refcount {
@@ -148,6 +151,17 @@ pub(crate) unsafe fn refcount_ptr(this: *mut Self) -> *mut Refcount {
// field projection is safe.
unsafe { &raw mut (*this).refcount }
}
+
+ /// Return a pointer to the `data` field of the `Self` pointed to by `this`.
+ ///
+ /// # Safety
+ ///
+ /// - `this` must point to a live allocation of at least the size of `Self`.
+ pub(crate) unsafe fn data_ptr(this: *mut Self) -> *mut T::RequestData {
+ // SAFETY: Because of the safety requirements of this function, the
+ // field projection is safe.
+ unsafe { &raw mut (*this).data }
+ }
}
// SAFETY: Exclusive access is thread-safe for `Request`. `Request` has no `&mut
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index c3cf56d52beec..46481754b1335 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -41,7 +41,7 @@ pub fn new(
// SAFETY: `blk_mq_tag_set` only contains integers and pointers, which
// all are allowed to be 0.
let tag_set: bindings::blk_mq_tag_set = unsafe { core::mem::zeroed() };
- let tag_set: Result<_> = core::mem::size_of::<RequestDataWrapper>()
+ let tag_set: Result<_> = core::mem::size_of::<RequestDataWrapper<T>>()
.try_into()
.map(|cmd_size| {
bindings::blk_mq_tag_set {
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 06/79] block: rust: add `Request` private data support
2026-02-15 23:34 ` [PATCH 06/79] block: rust: add `Request` private data support Andreas Hindborg
@ 2026-03-16 10:10 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:10 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:53AM +0100, Andreas Hindborg wrote:
> C block device drivers can attach private data to a `struct request`. This
> data is stored next to the request structure and is part of the request
> allocation set up during driver initialization.
>
> Expose this private request data area to Rust block device drivers.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Overall looks ok. A few nits below:
> ---
> drivers/block/rnull/rnull.rs | 5 +++++
> rust/kernel/block/mq.rs | 6 ++++++
> rust/kernel/block/mq/operations.rs | 24 +++++++++++++++++++++++-
> rust/kernel/block/mq/request.rs | 24 +++++++++++++++++++-----
> rust/kernel/block/mq/tag_set.rs | 2 +-
> 5 files changed, 54 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
> index 6a7f660d31998..065639fc4f941 100644
> --- a/drivers/block/rnull/rnull.rs
> +++ b/drivers/block/rnull/rnull.rs
> @@ -134,6 +134,11 @@ struct QueueData {
> #[vtable]
> impl Operations for NullBlkDevice {
> type QueueData = KBox<QueueData>;
> + type RequestData = ();
> +
> + fn new_request_data() -> impl PinInit<Self::RequestData> {
> + pin_init::zeroed::<Self::RequestData>()
Simpler to just return Ok(()) here.
> + }
>
> #[inline(always)]
> fn queue_rq(queue_data: &QueueData, rq: Owned<mq::Request<Self>>, _is_last: bool) -> Result {
> diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
> index b8ecd69abe980..a285b753ada88 100644
> --- a/rust/kernel/block/mq.rs
> +++ b/rust/kernel/block/mq.rs
> @@ -69,8 +69,14 @@
> //!
> //! #[vtable]
> //! impl Operations for MyBlkDevice {
> +//! type RequestData = ();
> //! type QueueData = ();
> //!
> +//! fn new_request_data(
> +//! ) -> impl PinInit<()> {
> +//! pin_init::zeroed::<()>()
Simpler to just return Ok(()) here.
> +//! }
> +//!
> //! fn queue_rq(_queue_data: (), rq: Owned<Request<Self>>, _is_last: bool) -> Result {
> //! rq.end_ok();
> //! Ok(())
> diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
> index 3dea79d647ff7..cd37b939bbf30 100644
> --- a/rust/kernel/block/mq/operations.rs
> +++ b/rust/kernel/block/mq/operations.rs
> @@ -13,6 +13,7 @@
> types::{ForeignOwnable, Owned},
> };
> use core::{marker::PhantomData, ptr::NonNull};
> +use pin_init::PinInit;
>
> type ForeignBorrowed<'a, T> = <T as ForeignOwnable>::Borrowed<'a>;
>
> @@ -28,10 +29,24 @@
> /// [module level documentation]: kernel::block::mq
> #[macros::vtable]
> pub trait Operations: Sized {
> + /// Data associated with a request. This data is located next to the request
> + /// structure.
> + ///
> + /// To be able to handle accessing this data from interrupt context, this
> + /// data must be `Sync`.
> + ///
> + /// The `RequestData` object is initialized when the requests are allocated
> + /// during queue initialization, and it is are dropped when the requests are
> + /// dropped during queue teardown.
> + type RequestData: Sized + Sync;
It was surprising to me that `request` is reused over many requests. I
think it could be a bit more obvious in the wording.
> /// Data associated with the `struct request_queue` that is allocated for
> /// the `GenDisk` associated with this `Operations` implementation.
> type QueueData: ForeignOwnable;
>
> + /// Called by the kernel to get an initializer for a `Pin<&mut RequestData>`.
> + fn new_request_data() -> impl PinInit<Self::RequestData>;
> +
> /// Called by the kernel to queue a request with the driver. If `is_last` is
> /// `false`, the driver is allowed to defer committing the request.
> fn queue_rq(
> @@ -236,6 +251,13 @@ impl<T: Operations> OperationsVTable<T> {
> // it is valid for writes.
> unsafe { RequestDataWrapper::refcount_ptr(pdu.as_ptr()).write(Refcount::new(0)) };
>
> + let initializer = T::new_request_data();
> +
> + // SAFETY: `pdu` is a valid pointer as established above. We do not
> + // touch `pdu` if `__pinned_init` returns an error. We promise ot to
typo
> diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
> index c3cf56d52beec..46481754b1335 100644
> --- a/rust/kernel/block/mq/tag_set.rs
> +++ b/rust/kernel/block/mq/tag_set.rs
> @@ -41,7 +41,7 @@ pub fn new(
> // SAFETY: `blk_mq_tag_set` only contains integers and pointers, which
> // all are allowed to be 0.
> let tag_set: bindings::blk_mq_tag_set = unsafe { core::mem::zeroed() };
> - let tag_set: Result<_> = core::mem::size_of::<RequestDataWrapper>()
> + let tag_set: Result<_> = core::mem::size_of::<RequestDataWrapper<T>>()
size_of in prelude.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 07/79] block: rust: allow `hrtimer::Timer` in `RequestData`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (5 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 06/79] block: rust: add `Request` private data support Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-02-15 23:34 ` [PATCH 08/79] block: rnull: add timer completion mode Andreas Hindborg
` (71 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
`Request` is essentially a smart pointer that derefs to
`Operations::RequestData`. To use an `HrTimer` in `Operations::RequestData`
via the `Request` pointer, we must implement `HrTimerPointer` for
`Request`.
Thus, implement `HrTimerPointer` and friends for `ARef<Request>`.
Publicly export `HrTimer::raw_cancel` and `HrTimer::into_c`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq.rs | 1 +
rust/kernel/block/mq/request.rs | 138 +++++++++++++++++++++++++++++++++++++++-
rust/kernel/time/hrtimer.rs | 5 +-
3 files changed, 141 insertions(+), 3 deletions(-)
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index a285b753ada88..cedaf85ba0b1d 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -108,4 +108,5 @@
pub use operations::Operations;
pub use request::Request;
+pub use request::RequestTimerHandle;
pub use tag_set::TagSet;
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 8a6c29ac627ee..f270060be27eb 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -12,9 +12,12 @@
atomic::ordering,
Refcount,
},
+ time::hrtimer::{
+ HasHrTimer, HrTimer, HrTimerCallback, HrTimerHandle, HrTimerMode, HrTimerPointer,
+ },
types::{Opaque, Ownable, OwnableRefCounted, Owned},
};
-use core::{marker::PhantomData, ptr::NonNull};
+use core::{ffi::c_void, marker::PhantomData, ptr::NonNull};
/// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
///
@@ -116,6 +119,11 @@ pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper<T> {
// valid as a shared reference.
unsafe { Self::wrapper_ptr(core::ptr::from_ref(self).cast_mut()).as_ref() }
}
+
+ /// Return a reference to the per-request data associated with this request.
+ pub fn data_ref(&self) -> &T::RequestData {
+ &self.wrapper_ref().data
+ }
}
/// A wrapper around data stored in the private area of the C [`struct request`].
@@ -300,3 +308,131 @@ fn into_shared(this: Owned<Self>) -> ARef<Self> {
unsafe { ARef::from_raw(Owned::into_raw(this)) }
}
}
+
+/// A handle for a timer that is embedded in a [`Request`] private data area.
+pub struct RequestTimerHandle<T>
+where
+ T: Operations,
+ T::RequestData: HasHrTimer<T::RequestData>,
+{
+ inner: ARef<Request<T>>,
+}
+
+// SAFETY: The drop implementation of `RequestTimerHandle` calls `cancel`, which cancels the timer
+// if it is running. `drop` will block if the timer handler is running. This is ensured via a call
+// to `HrTimer::raw_cancel` in the implementation of `cancel`.
+unsafe impl<T> HrTimerHandle for RequestTimerHandle<T>
+where
+ T: Operations,
+ T::RequestData: HasHrTimer<T::RequestData>,
+{
+ fn cancel(&mut self) -> bool {
+ let request_data_ptr = &self.inner.wrapper_ref().data as *const T::RequestData;
+
+ // SAFETY: As we obtained `self_ptr` from a valid reference above, it
+ // must point to a valid `U`.
+ let timer_ptr = unsafe {
+ <T::RequestData as HasHrTimer<T::RequestData>>::raw_get_timer(request_data_ptr)
+ };
+
+ // SAFETY: As `timer_ptr` points into `U` and `U` is valid, `timer_ptr`
+ // must point to a valid `HrTimer` instance.
+ unsafe { HrTimer::<T::RequestData>::raw_cancel(timer_ptr) }
+ }
+}
+
+impl<T> RequestTimerHandle<T>
+where
+ T: Operations,
+ T::RequestData: HasHrTimer<T::RequestData>,
+{
+ /// Drop the timer handle without cancelling the timer.
+ ///
+ /// This is safe because dropping the last [`ARef<Request>`] does not drop the [`Request`].
+ pub fn dismiss(mut self) {
+ let inner = core::ptr::from_mut(&mut self.inner);
+
+ // SAFETY: `inner` is valid for reads and writes, is properly aligned and nonnull. We have
+ // exclusive access to `inner` and we do not access `inner` after this call.
+ unsafe { core::ptr::drop_in_place(inner) };
+ core::mem::forget(self);
+ }
+}
+
+impl<T> Drop for RequestTimerHandle<T>
+where
+ T: Operations,
+ T::RequestData: HasHrTimer<T::RequestData>,
+{
+ fn drop(&mut self) {
+ self.cancel();
+ }
+}
+
+impl<T> HrTimerPointer for ARef<Request<T>>
+where
+ T: Operations,
+ T::RequestData: HasHrTimer<T::RequestData>,
+ T::RequestData: Sync,
+{
+ type TimerMode = <T::RequestData as HasHrTimer<T::RequestData>>::TimerMode;
+ type TimerHandle = RequestTimerHandle<T>;
+
+ fn start(self, expires: <Self::TimerMode as HrTimerMode>::Expires) -> RequestTimerHandle<T> {
+ let pdu_ptr = self.data_ref() as *const T::RequestData;
+
+ // SAFETY: `pdu_pointer` is coerced from a live reference to a `T` and this points to a
+ // valid `T`. The reference is valid until `T` is dropped, and the timer will be canceled
+ // before this.
+ unsafe { T::RequestData::start(pdu_ptr, expires) };
+
+ RequestTimerHandle { inner: self }
+ }
+}
+
+impl<T> kernel::time::hrtimer::RawHrTimerCallback for ARef<Request<T>>
+where
+ T: Operations,
+ T::RequestData: HasHrTimer<T::RequestData>,
+ T::RequestData: for<'a> HrTimerCallback<Pointer<'a> = ARef<Request<T>>>,
+ T::RequestData: Sync,
+{
+ type CallbackTarget<'a> = Self;
+
+ unsafe extern "C" fn run(ptr: *mut bindings::hrtimer) -> bindings::hrtimer_restart {
+ // `HrTimer` is `repr(transparent)`
+ let timer_ptr = ptr.cast::<kernel::time::hrtimer::HrTimer<T::RequestData>>();
+
+ // SAFETY: By C API contract `ptr` is the pointer we passed when
+ // enqueuing the timer, so it is a `HrTimer<T::RequestData>` embedded in a `T::RequestData`
+ let request_data_ptr = unsafe { T::RequestData::timer_container_of(timer_ptr) };
+
+ let offset = core::mem::offset_of!(RequestDataWrapper<T>, data);
+
+ // SAFETY: This sub stays within the `bindings::request` allocation and does not wrap.
+ let pdu_ptr = unsafe {
+ request_data_ptr
+ .cast::<u8>()
+ .sub(offset)
+ .cast::<RequestDataWrapper<T>>()
+ };
+
+ // SAFETY: This request pointer was passed to us by the kernel in `init_request_callback`.
+ let request_ptr = unsafe { bindings::blk_mq_rq_from_pdu(pdu_ptr.cast::<c_void>()) };
+
+ // SAFETY: By C API contract, we have ownership of the request.
+ let request_ref = unsafe { &*(request_ptr as *const Request<T>) };
+
+ request_ref.inc_ref();
+ // SAFETY: We just incremented the refcount above.
+ let aref: ARef<Request<T>> = unsafe { ARef::from_raw(NonNull::from(request_ref)) };
+
+ // SAFETY:
+ // - By C API contract `timer_ptr` is the pointer that we passed when queuing the timer, so
+ // it is a valid pointer to a `HrTimer<T>` embedded in a `T`.
+ // - We are within `RawHrTimerCallback::run`
+ let context = unsafe { kernel::time::hrtimer::HrTimerCallbackContext::from_raw(timer_ptr) };
+
+ T::RequestData::run(aref, context).into_c()
+ }
+}
diff --git a/rust/kernel/time/hrtimer.rs b/rust/kernel/time/hrtimer.rs
index b2272b059e504..0512a8dfee82a 100644
--- a/rust/kernel/time/hrtimer.rs
+++ b/rust/kernel/time/hrtimer.rs
@@ -160,7 +160,7 @@ unsafe fn raw_get(this: *const Self) -> *mut bindings::hrtimer {
/// # Safety
///
/// `this` must point to a valid `Self`.
- pub(crate) unsafe fn raw_cancel(this: *const Self) -> bool {
+ pub unsafe fn raw_cancel(this: *const Self) -> bool {
// SAFETY: `this` points to an allocation of at least `HrTimer` size.
let c_timer_ptr = unsafe { HrTimer::raw_get(this) };
@@ -514,7 +514,8 @@ pub enum HrTimerRestart {
}
impl HrTimerRestart {
- fn into_c(self) -> bindings::hrtimer_restart {
+ /// Convert `self` into an integer for FFI use.
+ pub fn into_c(self) -> bindings::hrtimer_restart {
self as bindings::hrtimer_restart
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 08/79] block: rnull: add timer completion mode
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (6 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 07/79] block: rust: allow `hrtimer::Timer` in `RequestData` Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-02-15 23:34 ` [PATCH 09/79] block: rust: introduce `kernel::block::bio` module Andreas Hindborg
` (70 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a timer completion mode to `rnull`. This will complete requests after a
specified time has elapsed. To use this mode of operation, set `irqmode` to
`2` and write a timeout in nanoseconds to `completion_nsec`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 13 +++++++--
drivers/block/rnull/rnull.rs | 63 ++++++++++++++++++++++++++++++++++++++---
2 files changed, 70 insertions(+), 6 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index eafa71dfc40d3..7952f41f42bfd 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -26,7 +26,8 @@
kstrtobool_bytes,
CString, //
},
- sync::Mutex, //
+ sync::Mutex,
+ time, //
};
use macros::{
configfs_simple_bool_field,
@@ -58,7 +59,7 @@ impl AttributeOperations<0> for Config {
fn show(_this: &Config, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
let mut writer = kernel::str::Formatter::new(page);
- writer.write_str("blocksize,size,rotational,irqmode\n")?;
+ writer.write_str("blocksize,size,rotational,irqmode,completion_nsec\n")?;
Ok(writer.bytes_written())
}
}
@@ -81,6 +82,7 @@ fn make_group(
rotational: 2,
size: 3,
irqmode: 4,
+ completion_nsec: 5,
],
};
@@ -96,6 +98,7 @@ fn make_group(
disk: None,
capacity_mib: 4096,
irq_mode: IRQMode::None,
+ completion_time: time::Delta::ZERO,
name: name.try_into()?,
}),
}),
@@ -108,6 +111,7 @@ fn make_group(
pub(crate) enum IRQMode {
None,
Soft,
+ Timer,
}
impl TryFrom<u8> for IRQMode {
@@ -117,6 +121,7 @@ fn try_from(value: u8) -> Result<Self> {
match value {
0 => Ok(Self::None),
1 => Ok(Self::Soft),
+ 2 => Ok(Self::Timer),
_ => Err(EINVAL),
}
}
@@ -127,6 +132,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::None => f.write_str("0")?,
Self::Soft => f.write_str("1")?,
+ Self::Timer => f.write_str("2")?,
}
Ok(())
}
@@ -146,6 +152,7 @@ struct DeviceConfigInner {
rotational: bool,
capacity_mib: u64,
irq_mode: IRQMode,
+ completion_time: time::Delta,
disk: Option<GenDisk<NullBlkDevice>>,
}
@@ -176,6 +183,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
guard.rotational,
guard.capacity_mib,
guard.irq_mode,
+ guard.completion_time,
)?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -191,6 +199,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_bool_field!(DeviceConfig, 2, rotational);
configfs_simple_field!(DeviceConfig, 3, capacity_mib, u64);
configfs_simple_field!(DeviceConfig, 4, irq_mode, IRQMode);
+configfs_simple_field!(DeviceConfig, 5, completion_time, i64, into time::Delta::from_nanos);
impl core::str::FromStr for IRQMode {
type Err = Error;
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 065639fc4f941..55e56c39f1c2c 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -28,6 +28,15 @@
Arc,
Mutex, //
},
+ time::{
+ hrtimer::{
+ HrTimerCallback,
+ HrTimerCallbackContext,
+ HrTimerPointer,
+ HrTimerRestart, //
+ },
+ Delta,
+ },
types::{
OwnableRefCounted,
Owned, //
@@ -61,7 +70,11 @@
},
irqmode: u8 {
default: 0,
- description: "IRQ completion handler. 0-none, 1-softirq",
+ description: "IRQ completion handler. 0-none, 1-softirq, 2-timer",
+ },
+ completion_nsec: u64 {
+ default: 10_000,
+ description: "Time in ns to complete a request in hardware. Default: 10,000ns",
},
},
}
@@ -81,6 +94,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
let mut disks = KVec::new();
let defer_init = move || -> Result<_, Error> {
+ let completion_time: i64 = (*module_parameters::completion_nsec.value()).try_into()?;
for i in 0..(*module_parameters::nr_devices.value()) {
let name = CString::try_from_fmt(fmt!("rnullb{}", i))?;
@@ -90,6 +104,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
*module_parameters::rotational.value() != 0,
*module_parameters::gb.value() * 1024,
(*module_parameters::irqmode.value()).try_into()?,
+ Delta::from_nanos(completion_time),
)?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -113,10 +128,17 @@ fn new(
rotational: bool,
capacity_mib: u64,
irq_mode: IRQMode,
+ completion_time: Delta,
) -> Result<GenDisk<Self>> {
let tagset = Arc::pin_init(TagSet::new(1, 256, 1), GFP_KERNEL)?;
- let queue_data = Box::new(QueueData { irq_mode }, GFP_KERNEL)?;
+ let queue_data = Box::new(
+ QueueData {
+ irq_mode,
+ completion_time,
+ },
+ GFP_KERNEL,
+ )?;
gen_disk::GenDiskBuilder::new()
.capacity_sectors(capacity_mib << (20 - block::SECTOR_SHIFT))
@@ -129,15 +151,43 @@ fn new(
struct QueueData {
irq_mode: IRQMode,
+ completion_time: Delta,
+}
+
+#[pin_data]
+struct Pdu {
+ #[pin]
+ timer: kernel::time::hrtimer::HrTimer<Self>,
+}
+
+impl HrTimerCallback for Pdu {
+ type Pointer<'a> = ARef<mq::Request<NullBlkDevice>>;
+
+ fn run(this: Self::Pointer<'_>, _context: HrTimerCallbackContext<'_, Self>) -> HrTimerRestart {
+ OwnableRefCounted::try_from_shared(this)
+ .map_err(|_e| kernel::error::code::EIO)
+ .expect("Failed to complete request")
+ .end_ok();
+ HrTimerRestart::NoRestart
+ }
+}
+
+kernel::impl_has_hr_timer! {
+ impl HasHrTimer<Self> for Pdu {
+ mode: kernel::time::hrtimer::RelativeMode<kernel::time::Monotonic>,
+ field: self.timer,
+ }
}
#[vtable]
impl Operations for NullBlkDevice {
type QueueData = KBox<QueueData>;
- type RequestData = ();
+ type RequestData = Pdu;
fn new_request_data() -> impl PinInit<Self::RequestData> {
- pin_init::zeroed::<Self::RequestData>()
+ pin_init!(Pdu {
+ timer <- kernel::time::hrtimer::HrTimer::new(),
+ })
}
#[inline(always)]
@@ -145,6 +195,11 @@ fn queue_rq(queue_data: &QueueData, rq: Owned<mq::Request<Self>>, _is_last: bool
match queue_data.irq_mode {
IRQMode::None => rq.end_ok(),
IRQMode::Soft => mq::Request::complete(rq.into()),
+ IRQMode::Timer => {
+ OwnableRefCounted::into_shared(rq)
+ .start(queue_data.completion_time)
+ .dismiss();
+ }
}
Ok(())
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 09/79] block: rust: introduce `kernel::block::bio` module
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (7 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 08/79] block: rnull: add timer completion mode Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 10:29 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 10/79] block: rust: add `command` getter to `Request` Andreas Hindborg
` (69 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add Rust abstractions for working with `struct bio`, the core IO command
descriptor for the block layer.
The `Bio` type wraps `struct bio` and provides safe access to the IO
vector describing the data buffers associated with the IO command. The
data buffers are represented as a vector of `Segment`s, where each
segment is a contiguous region of physical memory backed by `Page`.
The `BioSegmentIterator` provides iteration over segments in a single
bio, while `BioIterator` allows traversing a chain of bios. The
`Segment` type offers methods for copying data to and from pages, as
well as zeroing page contents, which are the fundamental operations
needed by block device drivers to process IO requests.
The `Request` type is extended with methods to access the bio chain
associated with a request, allowing drivers to iterate over all data
buffers that need to be processed.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/helpers/blk.c | 8 +
rust/kernel/block.rs | 1 +
rust/kernel/block/bio.rs | 143 +++++++++++++++
rust/kernel/block/bio/vec.rs | 389 ++++++++++++++++++++++++++++++++++++++++
rust/kernel/block/mq/request.rs | 46 +++++
rust/kernel/lib.rs | 2 +
rust/kernel/page.rs | 2 +-
7 files changed, 590 insertions(+), 1 deletion(-)
diff --git a/rust/helpers/blk.c b/rust/helpers/blk.c
index cc9f4e6a2d234..53beba8c7782d 100644
--- a/rust/helpers/blk.c
+++ b/rust/helpers/blk.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
+#include <linux/bio.h>
#include <linux/blk-mq.h>
#include <linux/blkdev.h>
@@ -12,3 +13,10 @@ struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu)
{
return blk_mq_rq_from_pdu(pdu);
}
+
+void rust_helper_bio_advance_iter_single(const struct bio *bio,
+ struct bvec_iter *iter,
+ unsigned int bytes)
+{
+ bio_advance_iter_single(bio, iter, bytes);
+}
diff --git a/rust/kernel/block.rs b/rust/kernel/block.rs
index 32c8d865afb62..17de727bc1047 100644
--- a/rust/kernel/block.rs
+++ b/rust/kernel/block.rs
@@ -2,6 +2,7 @@
//! Types for working with the block layer.
+pub mod bio;
pub mod mq;
/// Bit mask for masking out [`SECTOR_SIZE`].
diff --git a/rust/kernel/block/bio.rs b/rust/kernel/block/bio.rs
new file mode 100644
index 0000000000000..94062ea5281e6
--- /dev/null
+++ b/rust/kernel/block/bio.rs
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Types for working with the bio layer.
+//!
+//! C header: [`include/linux/blk_types.h`](../../include/linux/blk_types.h)
+
+use core::fmt;
+use core::marker::PhantomData;
+use core::ptr::NonNull;
+
+mod vec;
+
+pub use vec::BioSegmentIterator;
+pub use vec::Segment;
+
+use crate::types::Opaque;
+
+/// A block device IO descriptor (`struct bio`).
+///
+/// A `Bio` is the main unit of IO for the block layer. It describes an IO command and associated
+/// data buffers.
+///
+/// The data buffers associated with a `Bio` are represented by a vector of [`Segment`]s. These
+/// segments represent physically contiguous regions of memory. The memory is represented by
+/// [`Page`] descriptors internally.
+///
+/// The vector of [`Segment`]s can be iterated by obtaining a [`SegmentIterator`].
+///
+/// # Invariants
+///
+/// Instances of this type is always reference counted. A call to
+/// `bindings::bio_get()` ensures that the instance is valid for read at least
+/// until a matching call to `bindings :bio_put()`.
+#[repr(transparent)]
+pub struct Bio(Opaque<bindings::bio>);
+
+impl Bio {
+ /// Returns an iterator over segments in this `Bio`. Does not consider
+ /// segments of other bios in this bio chain.
+ #[inline(always)]
+ pub fn segment_iter(&mut self) -> BioSegmentIterator<'_> {
+ BioSegmentIterator::new(self)
+ }
+
+ /// Get the number of io vectors in this bio.
+ fn io_vec_count(&self) -> u16 {
+ // SAFETY: By the type invariant of `Bio` and existence of `&self`,
+ // `self.0` is valid for read.
+ unsafe { (*self.0.get()).bi_vcnt }
+ }
+
+ /// Get slice referencing the `bio_vec` array of this bio
+ #[inline(always)]
+ fn io_vec(&self) -> NonNull<bindings::bio_vec> {
+ let this = self.0.get();
+
+ // SAFETY: By the type invariant of `Bio` and existence of `&self`,
+ // `this` is valid for read.
+ let vec_ptr = unsafe { (*this).bi_io_vec };
+
+ // SAFETY: By C API contract, bi_io_vec is always set, even if bi_vcnt
+ // is zero.
+ unsafe { NonNull::new_unchecked(vec_ptr) }
+ }
+
+ /// Return a copy of the `bvec_iter` for this `Bio`. This iterator always
+ /// indexes to a valid `bio_vec` entry.
+ #[inline(always)]
+ fn raw_iter(&self) -> bindings::bvec_iter {
+ // SAFETY: By the type invariant of `Bio` and existence of `&self`,
+ // `self` is valid for read.
+ unsafe { (*self.0.get()).bi_iter }
+ }
+
+ /// Create an instance of `Bio` from a raw pointer.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that the `ptr` is valid for use as a reference to
+ /// `Bio` for the duration of `'a`.
+ #[inline(always)]
+ pub(crate) unsafe fn from_raw<'a>(ptr: *mut bindings::bio) -> Option<&'a Self> {
+ Some(
+ // SAFETY: by the safety requirement of this funciton, `ptr` is
+ // valid for read for the duration of the returned lifetime
+ unsafe { &*NonNull::new(ptr)?.as_ptr().cast::<Bio>() },
+ )
+ }
+
+ /// Create an instance of `Bio` from a raw pointer.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that the `ptr` is valid for use as a unique reference
+ /// to `Bio` for the duration of `'a`.
+ #[inline(always)]
+ pub(crate) unsafe fn from_raw_mut<'a>(ptr: *mut bindings::bio) -> Option<&'a mut Self> {
+ Some(
+ // SAFETY: by the safety requirement of this funciton, `ptr` is
+ // valid for read for the duration of the returned lifetime
+ unsafe { &mut *NonNull::new(ptr)?.as_ptr().cast::<Bio>() },
+ )
+ }
+}
+
+impl core::fmt::Display for Bio {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(
+ f,
+ "Bio({:?}, vcnt: {}, idx: {}, size: 0x{:x}, completed: 0x{:x})",
+ self.0.get(),
+ self.io_vec_count(),
+ self.raw_iter().bi_idx,
+ self.raw_iter().bi_size,
+ self.raw_iter().bi_bvec_done
+ )
+ }
+}
+
+/// An iterator over `Bio` in a bio chain, yielding `&mut Bio`.
+///
+/// # Invariants
+///
+/// `bio` must be either `None` or be valid for use as a `&mut Bio`.
+pub struct BioIterator<'a> {
+ pub(crate) bio: Option<NonNull<Bio>>,
+ pub(crate) _p: PhantomData<&'a ()>,
+}
+
+impl<'a> core::iter::Iterator for BioIterator<'a> {
+ type Item = &'a mut Bio;
+
+ #[inline(always)]
+ fn next(&mut self) -> Option<&'a mut Bio> {
+ let mut current = self.bio.take()?;
+ // SAFETY: By the type invariant of `Bio` and type invariant on `Self`,
+ // `current` is valid for use as a unique reference.
+ let next = unsafe { (*current.as_ref().0.get()).bi_next };
+ self.bio = NonNull::new(next.cast());
+ // SAFETY: By type invariant, `bio` is valid for use as a reference.
+ Some(unsafe { current.as_mut() })
+ }
+}
diff --git a/rust/kernel/block/bio/vec.rs b/rust/kernel/block/bio/vec.rs
new file mode 100644
index 0000000000000..20cea478050b9
--- /dev/null
+++ b/rust/kernel/block/bio/vec.rs
@@ -0,0 +1,389 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Types for working with `struct bio_vec` IO vectors
+//!
+//! C header: [`include/linux/bvec.h`](../../include/linux/bvec.h)
+
+use super::Bio;
+use crate::error::{code, Result};
+use crate::page::{Page, SafePage, PAGE_SIZE};
+use crate::prelude::*;
+use core::fmt;
+use core::mem::ManuallyDrop;
+
+/// A segment of an IO request.
+///
+/// [`Segment`] represents a contiguous range of physical memory addresses of an IO request. A
+/// segment has a offset and a length, representing the amount of data that needs to be processed.
+/// Processing the data increases the offset and reduces the length.
+///
+/// The data buffer of a [`Segment`] is borrowed from a `Bio`.
+///
+/// # Implementation details
+///
+/// In the context of user driven block IO, the pages backing a [`Segment`] are often mapped to user
+/// space concurrently with the IO operation. Further, the page backing a `Segment` may be part of
+/// multiple IO operations, if user space decides to issue multiple concurrent IO operations
+/// involving the same page. Thus, the data represented by a [`Segment`] must always be assumed to
+/// be subject to racy writes.
+///
+/// A [`Segemnt`] is a wrapper around a `strutct bio_vec`.
+///
+/// # Invariants
+///
+/// `bio_vec` must always be initialized and valid for read and write
+pub struct Segment<'a> {
+ bio_vec: bindings::bio_vec,
+ _marker: core::marker::PhantomData<&'a ()>,
+}
+
+impl Segment<'_> {
+ /// Get he length of the segment in bytes.
+ #[inline(always)]
+ pub fn len(&self) -> u32 {
+ self.bio_vec.bv_len
+ }
+
+ /// Returns true if the length of the segment is 0.
+ #[inline(always)]
+ pub fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Get the offset field of the `bio_vec`.
+ #[inline(always)]
+ pub fn offset(&self) -> usize {
+ self.bio_vec.bv_offset as usize
+ }
+
+ /// Advance the offset of the segment.
+ ///
+ /// If `count` is greater than the remaining size of the segment, an error
+ /// is returned.
+ pub fn advance(&mut self, count: u32) -> Result {
+ if self.len() < count {
+ return Err(code::EINVAL);
+ }
+
+ self.bio_vec.bv_offset += count;
+ self.bio_vec.bv_len -= count;
+ Ok(())
+ }
+
+ /// Copy data of this segment into `dst_page`.
+ ///
+ /// Copies data from the current offset to the next page boundary. That is `PAGE_SIZE -
+ /// (self.offeset() % PAGE_SIZE)` bytes of data. Data is placed at offset `self.offset()` in the
+ /// target page. This call will advance offset and reduce length of `self`.
+ ///
+ /// Returns the number of bytes copied.
+ #[inline(always)]
+ pub fn copy_to_page(&mut self, dst_page: Pin<&mut SafePage>, dst_offset: usize) -> usize {
+ // SAFETY: We are not moving out of `dst_page`.
+ let dst_page = unsafe { Pin::into_inner_unchecked(dst_page) };
+ let src_offset = self.offset() % PAGE_SIZE;
+ debug_assert!(dst_offset <= PAGE_SIZE);
+ let length = (PAGE_SIZE - src_offset)
+ .min(self.len() as usize)
+ .min(PAGE_SIZE - dst_offset);
+ let page_idx = self.offset() / PAGE_SIZE;
+
+ // SAFETY: self.bio_vec is valid and thus bv_page must be a valid
+ // pointer to a `struct page` array.
+ let src_page = unsafe { Page::from_raw(self.bio_vec.bv_page.add(page_idx)) };
+
+ src_page
+ .with_pointer_into_page(src_offset, length, |src| {
+ // SAFETY:
+ // - If `with_pointer_into_page` calls this closure, it has performed bounds
+ // checking and guarantees that `src` is valid for `length` bytes.
+ // - Any other operations to `src` are atomic or user space operations.
+ // - We have exclusive ownership of `dst_page` and thus this write will not race.
+ unsafe { dst_page.write_bytewise_atomic(src, dst_offset, length) }
+ })
+ .expect("Assertion failure, bounds check failed.");
+
+ self.advance(length as u32)
+ .expect("Assertion failure, bounds check failed.");
+
+ length
+ }
+
+ /// Copy data to the current page of this segment from `src_page`.
+ ///
+ /// Copies `PAGE_SIZE - (self.offset() % PAGE_SIZE` bytes of data from `src_page` to this
+ /// segment starting at `self.offset()` from offset `self.offset() % PAGE_SIZE`. This call
+ /// will advance offset and reduce length of `self`.
+ ///
+ /// Returns the number of bytes copied.
+ pub fn copy_from_page(&mut self, src_page: &SafePage, src_offset: usize) -> usize {
+ let dst_offset = self.offset() % PAGE_SIZE;
+ debug_assert!(src_offset <= PAGE_SIZE);
+ let length = (PAGE_SIZE - dst_offset)
+ .min(self.len() as usize)
+ .min(PAGE_SIZE - src_offset);
+ let page_idx = self.offset() / PAGE_SIZE;
+
+ // SAFETY: self.bio_vec is valid and thus bv_page must be a valid
+ // pointer to a `struct page`.
+ let dst_page = unsafe { Page::from_raw(self.bio_vec.bv_page.add(page_idx)) };
+
+ dst_page
+ .with_pointer_into_page(dst_offset, length, |dst| {
+ // SAFETY:
+ // - If `with_pointer_into_page` calls this closure, then it has performed bounds
+ // checks and guarantees that `dst` is valid for `length` bytes.
+ // - Any other operations to `dst` are atomic or user space operations.
+ // - Since we have a shared reference to `src_page`, the read cannot race with any
+ // writes to `src_page`.
+ unsafe { src_page.read_bytewise_atomic(dst, src_offset, length) }
+ })
+ .expect("Assertion failure, bounds check failed.");
+
+ self.advance(length as u32)
+ .expect("Assertion failure, bounds check failed.");
+
+ length
+ }
+
+ /// Copy zeroes to the current page of this segment.
+ ///
+ /// Copies `PAGE_SIZE - (self.offset() % PAGE_SIZE` bytes of data to this
+ /// segment starting at `self.offset()`. This call will advance offset and reduce length of
+ /// `self`.
+ ///
+ /// Returns the number of bytes written to this segment.
+ pub fn zero_page(&mut self) -> usize {
+ let offset = self.offset() % PAGE_SIZE;
+ let length = (PAGE_SIZE - offset).min(self.len() as usize);
+ let page_idx = self.offset() / PAGE_SIZE;
+
+ // SAFETY: self.bio_vec is valid and thus bv_page must be a valid
+ // pointer to a `struct page`. We do not own the page, but we prevent
+ // drop by wrapping the `Page` in `ManuallyDrop`.
+ let dst_page =
+ ManuallyDrop::new(unsafe { Page::from_raw(self.bio_vec.bv_page.add(page_idx)) });
+
+ // SAFETY: TODO: This migt race with user space writes.
+ unsafe { dst_page.fill_zero_raw(offset, length) }
+ .expect("Assertion failure, bounds check failed.");
+
+ self.advance(length as u32)
+ .expect("Assertion failure, bounds check failed.");
+
+ length
+ }
+}
+
+impl core::fmt::Display for Segment<'_> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(
+ f,
+ "Segment {:?} len: {}, offset: {}",
+ self.bio_vec.bv_page, self.bio_vec.bv_len, self.bio_vec.bv_offset
+ )
+ }
+}
+
+/// An iterator over `Segment`
+///
+/// # Invariants
+///
+/// If `iter.bi_size` > 0, `iter` must always index a valid `bio_vec` in `bio.io_vec()`.
+pub struct BioSegmentIterator<'a> {
+ bio: &'a mut Bio,
+ iter: bindings::bvec_iter,
+}
+
+impl<'a> BioSegmentIterator<'a> {
+ /// Creeate a new segemnt iterator for iterating the segments of `bio`. The
+ /// iterator starts at the beginning of `bio`.
+ #[inline(always)]
+ pub(crate) fn new(bio: &'a mut Bio) -> BioSegmentIterator<'a> {
+ let iter = bio.raw_iter();
+
+ // INVARIANT: `bio.raw_iter()` returns an index that indexes into a valid
+ // `bio_vec` in `bio.io_vec()`.
+ Self { bio, iter }
+ }
+
+ // The accessors in this implementation block are modelled after C side
+ // macros and static functions `bvec_iter_*` and `mp_bvec_iter_*` from
+ // bvec.h.
+
+ /// Construct a `bio_vec` from the current iterator state.
+ ///
+ /// This will return a `bio_vec`of size <= PAGE_SIZE
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ unsafe fn io_vec(&self) -> bindings::bio_vec {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By safety requirement of this function `self.iter.bi_size` is
+ // greater than 0.
+ unsafe {
+ bindings::bio_vec {
+ bv_page: self.page(),
+ bv_len: self.len(),
+ bv_offset: self.offset(),
+ }
+ }
+ }
+
+ /// Get the currently indexed `bio_vec` entry.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn bvec(&self) -> &bindings::bio_vec {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By the safety requirement of this function and the type
+ // invariant of `Self`, `self.iter.bi_idx` indexes into a valid
+ // `bio_vec`
+ unsafe { self.bio.io_vec().offset(self.iter.bi_idx as isize).as_ref() }
+ }
+
+ /// Get the as u32currently indexed page, indexing into pages of order >= 0.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn page(&self) -> *mut bindings::page {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By C API contract, the following offset cannot exceed pages
+ // allocated to this bio.
+ unsafe { self.mp_page().add(self.mp_page_idx()) }
+ }
+
+ /// Get the remaining bytes in the current page. Never more than PAGE_SIZE.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn len(&self) -> u32 {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By safety requirement of this function `self.iter.bi_size` is
+ // greater than 0.
+ unsafe {
+ self.mp_len()
+ .min((bindings::PAGE_SIZE as u32) - self.offset())
+ }
+ }
+
+ /// Get the offset from the last page boundary in the currently indexed
+ /// `bio_vec` entry. Never more than PAGE_SIZE.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn offset(&self) -> u32 {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By safety requirement of this function `self.iter.bi_size` is
+ // greater than 0.
+ unsafe { self.mp_offset() % (bindings::PAGE_SIZE as u32) }
+ }
+
+ /// Return the first page of the currently indexed `bio_vec` entry. This
+ /// might be a multi-page entry, meaning that page might have order > 0.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn mp_page(&self) -> *mut bindings::page {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By safety requirement of this function `self.iter.bi_size` is
+ // greater than 0.
+ unsafe { self.bvec().bv_page }
+ }
+
+ /// Get the offset in whole pages into the currently indexed `bio_vec`. This
+ /// can be more than 0 is the page has order > 0.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn mp_page_idx(&self) -> usize {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By safety requirement of this function `self.iter.bi_size` is
+ // greater than 0.
+ (unsafe { self.mp_offset() } / (bindings::PAGE_SIZE as u32)) as usize
+ }
+
+ /// Get the offset in the currently indexed `bio_vec` multi-page entry. This
+ /// can be more than `PAGE_SIZE` if the page has order > 0.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn mp_offset(&self) -> u32 {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By safety requirement of this function `self.iter.bi_size` is
+ // greater than 0.
+ unsafe { self.bvec().bv_offset + self.iter.bi_bvec_done }
+ }
+
+ /// Get the number of remaining bytes for the currently indexed `bio_vec`
+ /// entry. Can be more than PAGE_SIZE for `bio_vec` entries with pages of
+ /// order > 0.
+ ///
+ /// # Safety
+ ///
+ /// Caller must ensure that `self.iter.bi_size` > 0 before calling this
+ /// method.
+ #[inline(always)]
+ unsafe fn mp_len(&self) -> u32 {
+ debug_assert!(self.iter.bi_size > 0);
+ // SAFETY: By safety requirement of this function `self.iter.bi_size` is
+ // greater than 0.
+ self.iter
+ .bi_size
+ .min(unsafe { self.bvec().bv_len } - self.iter.bi_bvec_done)
+ }
+}
+
+impl<'a> core::iter::Iterator for BioSegmentIterator<'a> {
+ type Item = Segment<'a>;
+
+ #[inline(always)]
+ fn next(&mut self) -> Option<Self::Item> {
+ if self.iter.bi_size == 0 {
+ return None;
+ }
+
+ // SAFETY: We checked that `self.iter.bi_size` > 0 above.
+ let bio_vec_ret = unsafe { self.io_vec() };
+
+ // SAFETY: By existence of reference `&bio`, `bio.0` contains a valid
+ // `struct bio`. By type invariant of `BioSegmentItarator` `self.iter`
+ // indexes into a valid `bio_vec` entry. By C API contracit, `bv_len`
+ // does not exceed the size of the bio.
+ unsafe {
+ bindings::bio_advance_iter_single(
+ self.bio.0.get(),
+ core::ptr::from_mut(&mut self.iter),
+ bio_vec_ret.bv_len,
+ )
+ };
+
+ Some(Segment {
+ bio_vec: bio_vec_ret,
+ _marker: core::marker::PhantomData,
+ })
+ }
+}
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index f270060be27eb..b49197a0c66d7 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -19,6 +19,9 @@
};
use core::{ffi::c_void, marker::PhantomData, ptr::NonNull};
+use crate::block::bio::Bio;
+use crate::block::bio::BioIterator;
+
/// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
///
/// # Implementation details
@@ -92,6 +95,49 @@ pub fn complete(this: ARef<Self>) {
}
}
+ /// Get a reference to the first [`Bio`] in this request.
+ #[inline(always)]
+ pub fn bio(&self) -> Option<&Bio> {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and the deref
+ // is safe.
+ let ptr = unsafe { (*self.0.get()).bio };
+ // SAFETY: By C API contract, if `bio` is not null it will have a
+ // positive refcount at least for the duration of the lifetime of
+ // `&self`.
+ unsafe { Bio::from_raw(ptr) }
+ }
+
+ /// Get a mutable reference to the first [`Bio`] in this request.
+ #[inline(always)]
+ pub fn bio_mut(&mut self) -> Option<&mut Bio> {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and the deref
+ // is safe.
+ let ptr = unsafe { (*self.0.get()).bio };
+ // SAFETY: By C API contract, if `bio` is not null it will have a
+ // positive refcount at least for the duration of the lifetime of
+ // `&self`.
+ unsafe { Bio::from_raw_mut(ptr) }
+ }
+
+ /// Get an iterator over all bio structurs in this request.
+ #[inline(always)]
+ pub fn bio_iter_mut<'a>(self: &'a mut Owned<Self>) -> BioIterator<'a> {
+ // INVARIANT: By C API contract, if the bio pointer is not null, it is a valid `struct bio`.
+ // `NonNull::new` will return `None` if the pointer is null.
+ BioIterator {
+ // SAFETY: By type invariant `self.0` is a valid `struct request`.
+ bio: NonNull::new(unsafe { (*self.0.get()).bio.cast() }),
+ _p: PhantomData,
+ }
+ }
+
+ /// Get the target sector for the request.
+ #[inline(always)]
+ pub fn sector(&self) -> usize {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
+ unsafe { (*self.0.get()).__sector as usize }
+ }
+
/// Return a pointer to the [`RequestDataWrapper`] stored in the private area
/// of the request structure.
///
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 72642e6f1c295..73226348c729f 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -23,6 +23,8 @@
//
// Stable since Rust 1.80.0.
#![feature(slice_flatten)]
+// Stable in Rust 1.80
+#![feature(non_null_convenience)]
//
// Stable since Rust 1.81.0.
#![feature(lint_reasons)]
diff --git a/rust/kernel/page.rs b/rust/kernel/page.rs
index 22a920c15f45f..760aa286dc9ce 100644
--- a/rust/kernel/page.rs
+++ b/rust/kernel/page.rs
@@ -266,7 +266,7 @@ fn with_page_mapped<T>(&self, f: impl FnOnce(*mut u8) -> T) -> T {
/// different addresses. However, even if the addresses are different, the underlying memory is
/// still the same for these purposes (e.g., it's still a data race if they both write to the
/// same underlying byte at the same time).
- fn with_pointer_into_page<T>(
+ pub(crate) fn with_pointer_into_page<T>(
&self,
off: usize,
len: usize,
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 09/79] block: rust: introduce `kernel::block::bio` module
2026-02-15 23:34 ` [PATCH 09/79] block: rust: introduce `kernel::block::bio` module Andreas Hindborg
@ 2026-03-16 10:29 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:29 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:56AM +0100, Andreas Hindborg wrote:
> Add Rust abstractions for working with `struct bio`, the core IO command
> descriptor for the block layer.
>
> The `Bio` type wraps `struct bio` and provides safe access to the IO
> vector describing the data buffers associated with the IO command. The
> data buffers are represented as a vector of `Segment`s, where each
> segment is a contiguous region of physical memory backed by `Page`.
>
> The `BioSegmentIterator` provides iteration over segments in a single
> bio, while `BioIterator` allows traversing a chain of bios. The
> `Segment` type offers methods for copying data to and from pages, as
> well as zeroing page contents, which are the fundamental operations
> needed by block device drivers to process IO requests.
>
> The `Request` type is extended with methods to access the bio chain
> associated with a request, allowing drivers to iterate over all data
> buffers that need to be processed.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> ---
> rust/helpers/blk.c | 8 +
> rust/kernel/block.rs | 1 +
> rust/kernel/block/bio.rs | 143 +++++++++++++++
> rust/kernel/block/bio/vec.rs | 389 ++++++++++++++++++++++++++++++++++++++++
> rust/kernel/block/mq/request.rs | 46 +++++
> rust/kernel/lib.rs | 2 +
> rust/kernel/page.rs | 2 +-
> 7 files changed, 590 insertions(+), 1 deletion(-)
>
> diff --git a/rust/helpers/blk.c b/rust/helpers/blk.c
> index cc9f4e6a2d234..53beba8c7782d 100644
> --- a/rust/helpers/blk.c
> +++ b/rust/helpers/blk.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0
>
> +#include <linux/bio.h>
> #include <linux/blk-mq.h>
> #include <linux/blkdev.h>
>
> @@ -12,3 +13,10 @@ struct request *rust_helper_blk_mq_rq_from_pdu(void *pdu)
> {
> return blk_mq_rq_from_pdu(pdu);
> }
> +
> +void rust_helper_bio_advance_iter_single(const struct bio *bio,
> + struct bvec_iter *iter,
> + unsigned int bytes)
> +{
> + bio_advance_iter_single(bio, iter, bytes);
> +}
__rust_helper
> diff --git a/rust/kernel/block/bio.rs b/rust/kernel/block/bio.rs
> new file mode 100644
> index 0000000000000..94062ea5281e6
> --- /dev/null
> +++ b/rust/kernel/block/bio.rs
> @@ -0,0 +1,143 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +//! Types for working with the bio layer.
> +//!
> +//! C header: [`include/linux/blk_types.h`](../../include/linux/blk_types.h)
srctree/
> +/// A block device IO descriptor (`struct bio`).
> +///
> +/// A `Bio` is the main unit of IO for the block layer. It describes an IO command and associated
> +/// data buffers.
> +///
> +/// The data buffers associated with a `Bio` are represented by a vector of [`Segment`]s. These
> +/// segments represent physically contiguous regions of memory. The memory is represented by
> +/// [`Page`] descriptors internally.
> +///
> +/// The vector of [`Segment`]s can be iterated by obtaining a [`SegmentIterator`].
> +///
> +/// # Invariants
> +///
> +/// Instances of this type is always reference counted. A call to
> +/// `bindings::bio_get()` ensures that the instance is valid for read at least
> +/// until a matching call to `bindings :bio_put()`.
Refcounted? None of these methods are called anywhere, and you do not
implement AlwaysRefcounted.
> +#[repr(transparent)]
> +pub struct Bio(Opaque<bindings::bio>);
> +
> +impl Bio {
> + /// Returns an iterator over segments in this `Bio`. Does not consider
> + /// segments of other bios in this bio chain.
> + #[inline(always)]
> + pub fn segment_iter(&mut self) -> BioSegmentIterator<'_> {
Not `self: Pin<&mut Self>` here?
> + /// Create an instance of `Bio` from a raw pointer.
> + ///
> + /// # Safety
> + ///
> + /// Caller must ensure that the `ptr` is valid for use as a reference to
> + /// `Bio` for the duration of `'a`.
> + #[inline(always)]
> + pub(crate) unsafe fn from_raw<'a>(ptr: *mut bindings::bio) -> Option<&'a Self> {
> + Some(
> + // SAFETY: by the safety requirement of this funciton, `ptr` is
> + // valid for read for the duration of the returned lifetime
> + unsafe { &*NonNull::new(ptr)?.as_ptr().cast::<Bio>() },
> + )
> + }
> +
> + /// Create an instance of `Bio` from a raw pointer.
> + ///
> + /// # Safety
> + ///
> + /// Caller must ensure that the `ptr` is valid for use as a unique reference
> + /// to `Bio` for the duration of `'a`.
> + #[inline(always)]
> + pub(crate) unsafe fn from_raw_mut<'a>(ptr: *mut bindings::bio) -> Option<&'a mut Self> {
> + Some(
> + // SAFETY: by the safety requirement of this funciton, `ptr` is
> + // valid for read for the duration of the returned lifetime
> + unsafe { &mut *NonNull::new(ptr)?.as_ptr().cast::<Bio>() },
Why the Option? I imagine every caller has a non-null pointer?
> + )
> + }
> +}
> +
> +impl core::fmt::Display for Bio {
We have our own fmt trait now, right?
> + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
> + write!(
> + f,
> + "Bio({:?}, vcnt: {}, idx: {}, size: 0x{:x}, completed: 0x{:x})",
> + self.0.get(),
> + self.io_vec_count(),
> + self.raw_iter().bi_idx,
> + self.raw_iter().bi_size,
> + self.raw_iter().bi_bvec_done
This reads the entire `bi_iter` field three separate times. A local
variable may be a good idea.
> +/// An iterator over `Segment`
> +///
> +/// # Invariants
> +///
> +/// If `iter.bi_size` > 0, `iter` must always index a valid `bio_vec` in `bio.io_vec()`.
> +pub struct BioSegmentIterator<'a> {
> + bio: &'a mut Bio,
> + iter: bindings::bvec_iter,
> +}
> +
> +impl<'a> BioSegmentIterator<'a> {
> + /// Creeate a new segemnt iterator for iterating the segments of `bio`. The
typo
> +impl<'a> core::iter::Iterator for BioSegmentIterator<'a> {
> + type Item = Segment<'a>;
> +
> + #[inline(always)]
> + fn next(&mut self) -> Option<Self::Item> {
> + if self.iter.bi_size == 0 {
> + return None;
> + }
> +
> + // SAFETY: We checked that `self.iter.bi_size` > 0 above.
> + let bio_vec_ret = unsafe { self.io_vec() };
> +
> + // SAFETY: By existence of reference `&bio`, `bio.0` contains a valid
> + // `struct bio`. By type invariant of `BioSegmentItarator` `self.iter`
> + // indexes into a valid `bio_vec` entry. By C API contracit, `bv_len`
> + // does not exceed the size of the bio.
> + unsafe {
> + bindings::bio_advance_iter_single(
> + self.bio.0.get(),
> + core::ptr::from_mut(&mut self.iter),
Creating this BioSegmentItarator copies the bvec_iter from the Bio, and
then here you modify the copy. Is that the intent? Is the C type such
that copying it is always okay?
Also, is the C type such that moves are ok? It's playsible that the
answer is yes - the same applies in rust/kernel/iov.rs but it could be
clearer in e.g. "Invariants" that this is the case.
Nit: core::ptr::from_mut(&mut self.iter) -> &raw mut self.iter
> + /// Get a mutable reference to the first [`Bio`] in this request.
> + #[inline(always)]
> + pub fn bio_mut(&mut self) -> Option<&mut Bio> {
> + // SAFETY: By type invariant of `Self`, `self.0` is valid and the deref
> + // is safe.
> + let ptr = unsafe { (*self.0.get()).bio };
> + // SAFETY: By C API contract, if `bio` is not null it will have a
> + // positive refcount at least for the duration of the lifetime of
> + // `&self`.
> + unsafe { Bio::from_raw_mut(ptr) }
Surely &mut requires refcount == 1, not just positive refcount?
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 10/79] block: rust: add `command` getter to `Request`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (8 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 09/79] block: rust: introduce `kernel::block::bio` module Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 10:30 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 11/79] block: rust: mq: use GFP_KERNEL from prelude Andreas Hindborg
` (68 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method to extract the command operation code from a request. The
command is obtained by masking the lower bits of `cmd_flags` as defined by
`REQ_OP_BITS`. This allows Rust block drivers to determine the type of
operation being requested.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index b49197a0c66d7..0dd329ae93dfc 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -78,6 +78,12 @@ pub(crate) unsafe fn aref_from_raw(ptr: *mut bindings::request) -> ARef<Self> {
unsafe { ARef::from_raw(NonNull::new_unchecked(ptr.cast())) }
}
+ /// Get the command identifier for the request
+ pub fn command(&self) -> u32 {
+ // SAFETY: By C API contract and type invariant, `cmd_flags` is valid for read
+ unsafe { (*self.0.get()).cmd_flags & ((1 << bindings::REQ_OP_BITS) - 1) }
+ }
+
/// Complete the request by scheduling `Operations::complete` for
/// execution.
///
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 10/79] block: rust: add `command` getter to `Request`
2026-02-15 23:34 ` [PATCH 10/79] block: rust: add `command` getter to `Request` Andreas Hindborg
@ 2026-03-16 10:30 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:30 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:57AM +0100, Andreas Hindborg wrote:
> Add a method to extract the command operation code from a request. The
> command is obtained by masking the lower bits of `cmd_flags` as defined by
> `REQ_OP_BITS`. This allows Rust block drivers to determine the type of
> operation being requested.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
With the nit below fixed:
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> rust/kernel/block/mq/request.rs | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
> index b49197a0c66d7..0dd329ae93dfc 100644
> --- a/rust/kernel/block/mq/request.rs
> +++ b/rust/kernel/block/mq/request.rs
> @@ -78,6 +78,12 @@ pub(crate) unsafe fn aref_from_raw(ptr: *mut bindings::request) -> ARef<Self> {
> unsafe { ARef::from_raw(NonNull::new_unchecked(ptr.cast())) }
> }
>
> + /// Get the command identifier for the request
> + pub fn command(&self) -> u32 {
> + // SAFETY: By C API contract and type invariant, `cmd_flags` is valid for read
> + unsafe { (*self.0.get()).cmd_flags & ((1 << bindings::REQ_OP_BITS) - 1) }
Nit: scope of unsafe
unsafe { (*self.0.get()).cmd_flags } & ((1 << bindings::REQ_OP_BITS) - 1)
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 11/79] block: rust: mq: use GFP_KERNEL from prelude
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (9 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 10/79] block: rust: add `command` getter to `Request` Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 10:30 ` Alice Ryhl
2026-02-15 23:34 ` [PATCH 12/79] block: rust: add `TagSet` flags Andreas Hindborg
` (67 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Remove the explicit import of kernel::alloc::flags and use GFP_KERNEL
directly from the prelude in the module documentation example.
This simplifies the import list and follows the pattern of using
commonly used constants from the prelude.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq.rs | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index cedaf85ba0b1d..884bf18abbba5 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -57,7 +57,6 @@
//!
//! ```rust
//! use kernel::{
-//! alloc::flags,
//! block::mq::*,
//! new_mutex,
//! prelude::*,
@@ -93,7 +92,7 @@
//! }
//!
//! let tagset: Arc<TagSet<MyBlkDevice>> =
-//! Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?;
+//! Arc::pin_init(TagSet::new(1, 256, 1), GFP_KERNEL)?;
//! let mut disk = gen_disk::GenDiskBuilder::new()
//! .capacity_sectors(4096)
//! .build(fmt!("myblk"), tagset, ())?;
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 11/79] block: rust: mq: use GFP_KERNEL from prelude
2026-02-15 23:34 ` [PATCH 11/79] block: rust: mq: use GFP_KERNEL from prelude Andreas Hindborg
@ 2026-03-16 10:30 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:30 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:58AM +0100, Andreas Hindborg wrote:
> Remove the explicit import of kernel::alloc::flags and use GFP_KERNEL
> directly from the prelude in the module documentation example.
>
> This simplifies the import list and follows the pattern of using
> commonly used constants from the prelude.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 12/79] block: rust: add `TagSet` flags
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (10 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 11/79] block: rust: mq: use GFP_KERNEL from prelude Andreas Hindborg
@ 2026-02-15 23:34 ` Andreas Hindborg
2026-03-16 10:34 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 13/79] block: rnull: add memory backing Andreas Hindborg
` (66 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:34 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for `TagSet` flags by introducing a `Flags` type and adding
a flags parameter to `TagSet::new`. This allows configuring tagset
behavior such as blocking vs non-blocking operation.
The Flags type supports bitwise operations and provides values like
`Blocking` for common use cases. The module documentation example is
updated to demonstrate the new API.
For now, only a single flag is added.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 5 ++++-
rust/kernel/block/mq.rs | 6 +++---
rust/kernel/block/mq/tag_set.rs | 7 ++++++-
rust/kernel/block/mq/tag_set/flags.rs | 19 +++++++++++++++++++
4 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 55e56c39f1c2c..33c1144550a0e 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -130,7 +130,10 @@ fn new(
irq_mode: IRQMode,
completion_time: Delta,
) -> Result<GenDisk<Self>> {
- let tagset = Arc::pin_init(TagSet::new(1, 256, 1), GFP_KERNEL)?;
+ let tagset = Arc::pin_init(
+ TagSet::new(1, 256, 1, mq::tag_set::Flags::default()),
+ GFP_KERNEL,
+ )?;
let queue_data = Box::new(
QueueData {
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 884bf18abbba5..76e790cdb1f8f 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -57,7 +57,7 @@
//!
//! ```rust
//! use kernel::{
-//! block::mq::*,
+//! block::mq::{self, *},
//! new_mutex,
//! prelude::*,
//! sync::{aref::ARef, Arc, Mutex},
@@ -92,7 +92,7 @@
//! }
//!
//! let tagset: Arc<TagSet<MyBlkDevice>> =
-//! Arc::pin_init(TagSet::new(1, 256, 1), GFP_KERNEL)?;
+//! Arc::pin_init(TagSet::new(1, 256, 1, mq::tag_set::Flags::default()), GFP_KERNEL)?;
//! let mut disk = gen_disk::GenDiskBuilder::new()
//! .capacity_sectors(4096)
//! .build(fmt!("myblk"), tagset, ())?;
@@ -103,7 +103,7 @@
pub mod gen_disk;
mod operations;
mod request;
-mod tag_set;
+pub mod tag_set;
pub use operations::Operations;
pub use request::Request;
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index 46481754b1335..af214f7dd0c10 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -16,6 +16,10 @@
use core::{convert::TryInto, marker::PhantomData};
use pin_init::{pin_data, pinned_drop, PinInit};
+mod flags;
+pub use flags::Flag;
+pub use flags::Flags;
+
/// A wrapper for the C `struct blk_mq_tag_set`.
///
/// `struct blk_mq_tag_set` contains a `struct list_head` and so must be pinned.
@@ -37,6 +41,7 @@ pub fn new(
nr_hw_queues: u32,
num_tags: u32,
num_maps: u32,
+ flags: Flags,
) -> impl PinInit<Self, error::Error> {
// SAFETY: `blk_mq_tag_set` only contains integers and pointers, which
// all are allowed to be 0.
@@ -51,7 +56,7 @@ pub fn new(
numa_node: bindings::NUMA_NO_NODE,
queue_depth: num_tags,
cmd_size,
- flags: 0,
+ flags: flags.into_inner(),
driver_data: core::ptr::null_mut::<crate::ffi::c_void>(),
nr_maps: num_maps,
..tag_set
diff --git a/rust/kernel/block/mq/tag_set/flags.rs b/rust/kernel/block/mq/tag_set/flags.rs
new file mode 100644
index 0000000000000..768db938b9a95
--- /dev/null
+++ b/rust/kernel/block/mq/tag_set/flags.rs
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use kernel::prelude::*;
+
+impl_flags! {
+
+ /// Flags to be used when creating [`super::TagSet`] objects.
+ #[derive(Debug, Clone, Default, Copy, PartialEq, Eq)]
+ pub struct Flags(u32);
+
+ /// Allowed values for [`Flags`].
+ #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+ pub enum Flag {
+ /// Indicate that the queues associated with this tag set might sleep when
+ /// processing IO. When this flag is not set, IO is processed in atomic
+ /// context. When this flag is set, IO is processed in process context.
+ Blocking = bindings::BLK_MQ_F_BLOCKING,
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 12/79] block: rust: add `TagSet` flags
2026-02-15 23:34 ` [PATCH 12/79] block: rust: add `TagSet` flags Andreas Hindborg
@ 2026-03-16 10:34 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:34 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:34:59AM +0100, Andreas Hindborg wrote:
> Add support for `TagSet` flags by introducing a `Flags` type and adding
> a flags parameter to `TagSet::new`. This allows configuring tagset
> behavior such as blocking vs non-blocking operation.
>
> The Flags type supports bitwise operations and provides values like
> `Blocking` for common use cases. The module documentation example is
> updated to demonstrate the new API.
>
> For now, only a single flag is added.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
with nits fixed:
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> /// A wrapper for the C `struct blk_mq_tag_set`.
> ///
> /// `struct blk_mq_tag_set` contains a `struct list_head` and so must be pinned.
> @@ -37,6 +41,7 @@ pub fn new(
> nr_hw_queues: u32,
> num_tags: u32,
> num_maps: u32,
> + flags: Flags,
> ) -> impl PinInit<Self, error::Error> {
> // SAFETY: `blk_mq_tag_set` only contains integers and pointers, which
> // all are allowed to be 0.
> @@ -51,7 +56,7 @@ pub fn new(
> numa_node: bindings::NUMA_NO_NODE,
> queue_depth: num_tags,
> cmd_size,
> - flags: 0,
> + flags: flags.into_inner(),
> driver_data: core::ptr::null_mut::<crate::ffi::c_void>(),
c_void in prelude.
> nr_maps: num_maps,
> ..tag_set
> diff --git a/rust/kernel/block/mq/tag_set/flags.rs b/rust/kernel/block/mq/tag_set/flags.rs
> new file mode 100644
> index 0000000000000..768db938b9a95
> --- /dev/null
> +++ b/rust/kernel/block/mq/tag_set/flags.rs
> @@ -0,0 +1,19 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +use kernel::prelude::*;
> +
> +impl_flags! {
> +
> + /// Flags to be used when creating [`super::TagSet`] objects.
> + #[derive(Debug, Clone, Default, Copy, PartialEq, Eq)]
> + pub struct Flags(u32);
Nit: Spurious newline in beginning of macro.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 13/79] block: rnull: add memory backing
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (11 preceding siblings ...)
2026-02-15 23:34 ` [PATCH 12/79] block: rust: add `TagSet` flags Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:38 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 14/79] block: rnull: add submit queue count config option Andreas Hindborg
` (65 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add memory backing to the rust null block driver. This implementation will
always allocate a page on write, even though a page backing the written
sector is already allocated, in which case the page will be released again.
A later patch will fix this inefficiency.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 37 +++++++++++-
drivers/block/rnull/rnull.rs | 125 ++++++++++++++++++++++++++++++++++------
2 files changed, 144 insertions(+), 18 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 7952f41f42bfd..b5dc30c5d3e20 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -59,7 +59,7 @@ impl AttributeOperations<0> for Config {
fn show(_this: &Config, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
let mut writer = kernel::str::Formatter::new(page);
- writer.write_str("blocksize,size,rotational,irqmode,completion_nsec\n")?;
+ writer.write_str("blocksize,size,rotational,irqmode,completion_nsec,memory_backed\n")?;
Ok(writer.bytes_written())
}
}
@@ -83,6 +83,7 @@ fn make_group(
size: 3,
irqmode: 4,
completion_nsec: 5,
+ memory_backed: 6,
],
};
@@ -100,6 +101,7 @@ fn make_group(
irq_mode: IRQMode::None,
completion_time: time::Delta::ZERO,
name: name.try_into()?,
+ memory_backed: false,
}),
}),
core::iter::empty(),
@@ -154,6 +156,7 @@ struct DeviceConfigInner {
irq_mode: IRQMode,
completion_time: time::Delta,
disk: Option<GenDisk<NullBlkDevice>>,
+ memory_backed: bool,
}
#[vtable]
@@ -184,6 +187,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
guard.capacity_mib,
guard.irq_mode,
guard.completion_time,
+ guard.memory_backed,
)?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -209,3 +213,34 @@ fn from_str(s: &str) -> Result<Self> {
value.try_into()
}
}
+
+#[vtable]
+impl configfs::AttributeOperations<6> for DeviceConfig {
+ type Data = DeviceConfig;
+
+ fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+ let mut writer = kernel::str::Formatter::new(page);
+
+ if this.data.lock().memory_backed {
+ writer.write_fmt(fmt!("1\n"))?;
+ } else {
+ writer.write_fmt(fmt!("0\n"))?;
+ }
+
+ Ok(writer.bytes_written())
+ }
+
+ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
+ if this.data.lock().powered {
+ return Err(EBUSY);
+ }
+
+ this.data.lock().memory_backed = core::str::from_utf8(page)?
+ .trim()
+ .parse::<u8>()
+ .map_err(|_| kernel::error::code::EINVAL)?
+ != 0;
+
+ Ok(())
+ }
+}
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 33c1144550a0e..a1156a368c467 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -6,8 +6,10 @@
use configfs::IRQMode;
use kernel::{
+ bindings,
block::{
self,
+ bio::Segment,
mq::{
self,
gen_disk::{
@@ -19,15 +21,12 @@
},
},
error::Result,
- new_mutex,
+ new_mutex, new_xarray,
+ page::SafePage,
pr_info,
prelude::*,
str::CString,
- sync::{
- aref::ARef,
- Arc,
- Mutex, //
- },
+ sync::{aref::ARef, Arc, Mutex},
time::{
hrtimer::{
HrTimerCallback,
@@ -40,7 +39,8 @@
types::{
OwnableRefCounted,
Owned, //
- }, //
+ },
+ xarray::XArray,
};
use pin_init::PinInit;
@@ -76,6 +76,10 @@
default: 10_000,
description: "Time in ns to complete a request in hardware. Default: 10,000ns",
},
+ memory_backed: u8 {
+ default: 0,
+ description: "Create a memory-backed block device. 0-false, 1-true. Default: 0",
+ },
},
}
@@ -105,6 +109,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
*module_parameters::gb.value() * 1024,
(*module_parameters::irqmode.value()).try_into()?,
Delta::from_nanos(completion_time),
+ *module_parameters::memory_backed.value() != 0,
)?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -129,17 +134,23 @@ fn new(
capacity_mib: u64,
irq_mode: IRQMode,
completion_time: Delta,
+ memory_backed: bool,
) -> Result<GenDisk<Self>> {
- let tagset = Arc::pin_init(
- TagSet::new(1, 256, 1, mq::tag_set::Flags::default()),
- GFP_KERNEL,
- )?;
+ let flags = if memory_backed {
+ mq::tag_set::Flag::Blocking.into()
+ } else {
+ mq::tag_set::Flags::default()
+ };
+
+ let tagset = Arc::pin_init(TagSet::new(1, 256, 1, flags), GFP_KERNEL)?;
- let queue_data = Box::new(
- QueueData {
+ let queue_data = Box::pin_init(
+ pin_init!(QueueData {
+ tree <- new_xarray!(kernel::xarray::AllocKind::Alloc),
irq_mode,
completion_time,
- },
+ memory_backed,
+ }),
GFP_KERNEL,
)?;
@@ -150,11 +161,72 @@ fn new(
.rotational(rotational)
.build(fmt!("{}", name.to_str()?), tagset, queue_data)
}
+
+ #[inline(always)]
+ fn write(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
+ while !segment.is_empty() {
+ let page = SafePage::alloc_page(GFP_NOIO)?;
+ let mut tree = tree.lock();
+
+ let page_idx = sector >> block::PAGE_SECTORS_SHIFT;
+
+ let page = if let Some(page) = tree.get_mut(page_idx) {
+ page
+ } else {
+ tree.store(page_idx, page, GFP_NOIO)?;
+ tree.get_mut(page_idx).unwrap()
+ };
+
+ let page_offset = (sector & block::SECTOR_MASK as usize) << block::SECTOR_SHIFT;
+ sector += segment.copy_to_page(page, page_offset) >> block::SECTOR_SHIFT;
+ }
+ Ok(())
+ }
+
+ #[inline(always)]
+ fn read(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
+ let tree = tree.lock();
+
+ while !segment.is_empty() {
+ let idx = sector >> block::PAGE_SECTORS_SHIFT;
+
+ if let Some(page) = tree.get(idx) {
+ let page_offset = (sector & block::SECTOR_MASK as usize) << block::SECTOR_SHIFT;
+ sector += segment.copy_from_page(page, page_offset) >> block::SECTOR_SHIFT;
+ } else {
+ sector += segment.zero_page() >> block::SECTOR_SHIFT;
+ }
+ }
+
+ Ok(())
+ }
+
+ #[inline(never)]
+ fn transfer(
+ command: bindings::req_op,
+ tree: &Tree,
+ sector: usize,
+ segment: Segment<'_>,
+ ) -> Result {
+ match command {
+ bindings::req_op_REQ_OP_WRITE => Self::write(tree, sector, segment)?,
+ bindings::req_op_REQ_OP_READ => Self::read(tree, sector, segment)?,
+ _ => (),
+ }
+ Ok(())
+ }
}
+type TreeNode = Owned<SafePage>;
+type Tree = XArray<TreeNode>;
+
+#[pin_data]
struct QueueData {
+ #[pin]
+ tree: Tree,
irq_mode: IRQMode,
completion_time: Delta,
+ memory_backed: bool,
}
#[pin_data]
@@ -184,7 +256,7 @@ impl HasHrTimer<Self> for Pdu {
#[vtable]
impl Operations for NullBlkDevice {
- type QueueData = KBox<QueueData>;
+ type QueueData = Pin<KBox<QueueData>>;
type RequestData = Pdu;
fn new_request_data() -> impl PinInit<Self::RequestData> {
@@ -194,7 +266,26 @@ fn new_request_data() -> impl PinInit<Self::RequestData> {
}
#[inline(always)]
- fn queue_rq(queue_data: &QueueData, rq: Owned<mq::Request<Self>>, _is_last: bool) -> Result {
+ fn queue_rq(
+ queue_data: Pin<&QueueData>,
+ mut rq: Owned<mq::Request<Self>>,
+ _is_last: bool,
+ ) -> Result {
+ if queue_data.memory_backed {
+ let tree = &queue_data.tree;
+ let command = rq.command();
+ let mut sector = rq.sector();
+
+ for bio in rq.bio_iter_mut() {
+ let segment_iter = bio.segment_iter();
+ for segment in segment_iter {
+ let length = segment.len();
+ Self::transfer(command, tree, sector, segment)?;
+ sector += length as usize >> block::SECTOR_SHIFT;
+ }
+ }
+ }
+
match queue_data.irq_mode {
IRQMode::None => rq.end_ok(),
IRQMode::Soft => mq::Request::complete(rq.into()),
@@ -207,7 +298,7 @@ fn queue_rq(queue_data: &QueueData, rq: Owned<mq::Request<Self>>, _is_last: bool
Ok(())
}
- fn commit_rqs(_queue_data: &QueueData) {}
+ fn commit_rqs(_queue_data: Pin<&QueueData>) {}
fn complete(rq: ARef<mq::Request<Self>>) {
OwnableRefCounted::try_from_shared(rq)
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 13/79] block: rnull: add memory backing
2026-02-15 23:35 ` [PATCH 13/79] block: rnull: add memory backing Andreas Hindborg
@ 2026-03-16 10:38 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:38 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:00AM +0100, Andreas Hindborg wrote:
> Add memory backing to the rust null block driver. This implementation will
> always allocate a page on write, even though a page backing the written
> sector is already allocated, in which case the page will be released again.
> A later patch will fix this inefficiency.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Same comment as elsewhere about parsing booleans with kstrtobool.
> +type TreeNode = Owned<SafePage>;
> +type Tree = XArray<TreeNode>;
> +
> +#[pin_data]
> struct QueueData {
> + #[pin]
> + tree: Tree,
Why this type alias? Seems cleaner to just say
struct QueueData {
#[pin]
tree: XArray<TreeNode>,
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 14/79] block: rnull: add submit queue count config option
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (12 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 13/79] block: rnull: add memory backing Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:40 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 15/79] block: rnull: add `use_per_node_hctx` " Andreas Hindborg
` (64 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Allow user space to control the number of submission queues when creating
null block devices.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 56 +++++++++++++++++++++++++++++++++--------
drivers/block/rnull/rnull.rs | 56 +++++++++++++++++++++++++++--------------
2 files changed, 83 insertions(+), 29 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index b5dc30c5d3e20..fd3cbf7aa012e 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -59,7 +59,10 @@ impl AttributeOperations<0> for Config {
fn show(_this: &Config, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
let mut writer = kernel::str::Formatter::new(page);
- writer.write_str("blocksize,size,rotational,irqmode,completion_nsec,memory_backed\n")?;
+ writer.write_str(
+ "blocksize,size,rotational,irqmode,completion_nsec,memory_backed\
+ submit_queues\n",
+ )?;
Ok(writer.bytes_written())
}
}
@@ -84,6 +87,7 @@ fn make_group(
irqmode: 4,
completion_nsec: 5,
memory_backed: 6,
+ submit_queues: 7,
],
};
@@ -102,6 +106,7 @@ fn make_group(
completion_time: time::Delta::ZERO,
name: name.try_into()?,
memory_backed: false,
+ submit_queues: 1,
}),
}),
core::iter::empty(),
@@ -157,6 +162,7 @@ struct DeviceConfigInner {
completion_time: time::Delta,
disk: Option<GenDisk<NullBlkDevice>>,
memory_backed: bool,
+ submit_queues: u32,
}
#[vtable]
@@ -180,15 +186,16 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
let mut guard = this.data.lock();
if !guard.powered && power_op {
- guard.disk = Some(NullBlkDevice::new(
- &guard.name,
- guard.block_size,
- guard.rotational,
- guard.capacity_mib,
- guard.irq_mode,
- guard.completion_time,
- guard.memory_backed,
- )?);
+ guard.disk = Some(NullBlkDevice::new(crate::NullBlkOptions {
+ name: &guard.name,
+ block_size: guard.block_size,
+ rotational: guard.rotational,
+ capacity_mib: guard.capacity_mib,
+ irq_mode: guard.irq_mode,
+ completion_time: guard.completion_time,
+ memory_backed: guard.memory_backed,
+ submit_queues: guard.submit_queues,
+ })?);
guard.powered = true;
} else if guard.powered && !power_op {
drop(guard.disk.take());
@@ -244,3 +251,32 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
Ok(())
}
}
+
+#[vtable]
+impl configfs::AttributeOperations<7> for DeviceConfig {
+ type Data = DeviceConfig;
+
+ fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+ let mut writer = kernel::str::Formatter::new(page);
+ writer.write_fmt(fmt!("{}\n", this.data.lock().submit_queues))?;
+ Ok(writer.bytes_written())
+ }
+
+ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
+ if this.data.lock().powered {
+ return Err(EBUSY);
+ }
+
+ let text = core::str::from_utf8(page)?.trim();
+ let value = text
+ .parse::<u32>()
+ .map_err(|_| kernel::error::code::EINVAL)?;
+
+ if value == 0 || value > kernel::num_possible_cpus() {
+ return Err(kernel::error::code::EINVAL);
+ }
+
+ this.data.lock().submit_queues = value;
+ Ok(())
+ }
+}
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index a1156a368c467..55ee5165b90b3 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -80,6 +80,10 @@
default: 0,
description: "Create a memory-backed block device. 0-false, 1-true. Default: 0",
},
+ submit_queues: u32 {
+ default: 1,
+ description: "Number of submission queues",
+ },
},
}
@@ -102,15 +106,16 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
for i in 0..(*module_parameters::nr_devices.value()) {
let name = CString::try_from_fmt(fmt!("rnullb{}", i))?;
- let disk = NullBlkDevice::new(
- &name,
- *module_parameters::bs.value(),
- *module_parameters::rotational.value() != 0,
- *module_parameters::gb.value() * 1024,
- (*module_parameters::irqmode.value()).try_into()?,
- Delta::from_nanos(completion_time),
- *module_parameters::memory_backed.value() != 0,
- )?;
+ let disk = NullBlkDevice::new(NullBlkOptions {
+ name: &name,
+ block_size: *module_parameters::bs.value(),
+ rotational: *module_parameters::rotational.value() != 0,
+ capacity_mib: *module_parameters::gb.value() * 1024,
+ irq_mode: (*module_parameters::irqmode.value()).try_into()?,
+ completion_time: Delta::from_nanos(completion_time),
+ memory_backed: *module_parameters::memory_backed.value() != 0,
+ submit_queues: *module_parameters::submit_queues.value(),
+ })?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -124,25 +129,38 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
}
}
+struct NullBlkOptions<'a> {
+ name: &'a CStr,
+ block_size: u32,
+ rotational: bool,
+ capacity_mib: u64,
+ irq_mode: IRQMode,
+ completion_time: Delta,
+ memory_backed: bool,
+ submit_queues: u32,
+}
struct NullBlkDevice;
impl NullBlkDevice {
- fn new(
- name: &CStr,
- block_size: u32,
- rotational: bool,
- capacity_mib: u64,
- irq_mode: IRQMode,
- completion_time: Delta,
- memory_backed: bool,
- ) -> Result<GenDisk<Self>> {
+ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
+ let NullBlkOptions {
+ name,
+ block_size,
+ rotational,
+ capacity_mib,
+ irq_mode,
+ completion_time,
+ memory_backed,
+ submit_queues,
+ } = options;
+
let flags = if memory_backed {
mq::tag_set::Flag::Blocking.into()
} else {
mq::tag_set::Flags::default()
};
- let tagset = Arc::pin_init(TagSet::new(1, 256, 1, flags), GFP_KERNEL)?;
+ let tagset = Arc::pin_init(TagSet::new(submit_queues, 256, 1, flags), GFP_KERNEL)?;
let queue_data = Box::pin_init(
pin_init!(QueueData {
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 14/79] block: rnull: add submit queue count config option
2026-02-15 23:35 ` [PATCH 14/79] block: rnull: add submit queue count config option Andreas Hindborg
@ 2026-03-16 10:40 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:40 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:01AM +0100, Andreas Hindborg wrote:
> Allow user space to control the number of submission queues when creating
> null block devices.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> ---
> drivers/block/rnull/configfs.rs | 56 +++++++++++++++++++++++++++++++++--------
> drivers/block/rnull/rnull.rs | 56 +++++++++++++++++++++++++++--------------
> 2 files changed, 83 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
> index b5dc30c5d3e20..fd3cbf7aa012e 100644
> --- a/drivers/block/rnull/configfs.rs
> +++ b/drivers/block/rnull/configfs.rs
> @@ -59,7 +59,10 @@ impl AttributeOperations<0> for Config {
>
> fn show(_this: &Config, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> let mut writer = kernel::str::Formatter::new(page);
> - writer.write_str("blocksize,size,rotational,irqmode,completion_nsec,memory_backed\n")?;
> + writer.write_str(
> + "blocksize,size,rotational,irqmode,completion_nsec,memory_backed\
> + submit_queues\n",
> + )?;
Missing comma? If so, this may indicate missing test coverage :)
> +struct NullBlkOptions<'a> {
> + name: &'a CStr,
> + block_size: u32,
> + rotational: bool,
> + capacity_mib: u64,
> + irq_mode: IRQMode,
> + completion_time: Delta,
> + memory_backed: bool,
> + submit_queues: u32,
> +}
> struct NullBlkDevice;
>
> impl NullBlkDevice {
> - fn new(
> - name: &CStr,
> - block_size: u32,
> - rotational: bool,
> - capacity_mib: u64,
> - irq_mode: IRQMode,
> - completion_time: Delta,
> - memory_backed: bool,
> - ) -> Result<GenDisk<Self>> {
> + fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
> + let NullBlkOptions {
> + name,
> + block_size,
> + rotational,
> + capacity_mib,
> + irq_mode,
> + completion_time,
> + memory_backed,
> + submit_queues,
> + } = options;
Nice!
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 15/79] block: rnull: add `use_per_node_hctx` config option
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (13 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 14/79] block: rnull: add submit queue count config option Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:43 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 16/79] block: rust: allow specifying home node when constructing `TagSet` Andreas Hindborg
` (63 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a configfs attribute to enable per-NUMA-node hardware contexts.
When enabled, the driver creates one hardware queue per NUMA node
instead of the default configuration.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 26 ++++++++++++++++++++++++--
drivers/block/rnull/rnull.rs | 28 ++++++++++++++++++++++------
2 files changed, 46 insertions(+), 8 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index fd3cbf7aa012e..b05bfc23090c2 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -30,8 +30,11 @@
time, //
};
use macros::{
+ configfs_attribute,
configfs_simple_bool_field,
- configfs_simple_field, //
+ configfs_simple_field,
+ show_field,
+ store_with_power_check, //
};
use pin_init::PinInit;
@@ -61,7 +64,7 @@ impl AttributeOperations<0> for Config {
let mut writer = kernel::str::Formatter::new(page);
writer.write_str(
"blocksize,size,rotational,irqmode,completion_nsec,memory_backed\
- submit_queues\n",
+ submit_queues,use_per_node_hctx\n",
)?;
Ok(writer.bytes_written())
}
@@ -88,6 +91,7 @@ fn make_group(
completion_nsec: 5,
memory_backed: 6,
submit_queues: 7,
+ use_per_node_hctx: 8,
],
};
@@ -280,3 +284,21 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
Ok(())
}
}
+
+configfs_attribute!(DeviceConfig, 8,
+ show: |this, page| show_field(
+ this.data.lock().submit_queues == kernel::num_online_nodes(), page
+ ),
+ store: |this, page| store_with_power_check(this, page, |this, page| {
+ let value = core::str::from_utf8(page)?
+ .trim()
+ .parse::<u8>()
+ .map_err(|_| kernel::error::code::EINVAL)?
+ != 0;
+
+ if value {
+ this.data.lock().submit_queues *= kernel::num_online_nodes();
+ }
+ Ok(())
+ })
+);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 55ee5165b90b3..990dfcf95c9de 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -21,12 +21,17 @@
},
},
error::Result,
- new_mutex, new_xarray,
+ new_mutex,
+ new_xarray,
page::SafePage,
pr_info,
prelude::*,
str::CString,
- sync::{aref::ARef, Arc, Mutex},
+ sync::{
+ aref::ARef,
+ Arc,
+ Mutex, //
+ },
time::{
hrtimer::{
HrTimerCallback,
@@ -40,7 +45,7 @@
OwnableRefCounted,
Owned, //
},
- xarray::XArray,
+ xarray::XArray, //
};
use pin_init::PinInit;
@@ -73,8 +78,9 @@
description: "IRQ completion handler. 0-none, 1-softirq, 2-timer",
},
completion_nsec: u64 {
- default: 10_000,
- description: "Time in ns to complete a request in hardware. Default: 10,000ns",
+ default: 10_000,
+ description:
+ "Time in ns to complete a request in hardware. Default: 10,000ns",
},
memory_backed: u8 {
default: 0,
@@ -84,6 +90,11 @@
default: 1,
description: "Number of submission queues",
},
+ use_per_node_hctx: u8 {
+ default: 0,
+ description:
+ "Use per-node allocation for hardware context queues, 0-false, 1-true. Default: 0-false",
+ },
},
}
@@ -106,6 +117,11 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
for i in 0..(*module_parameters::nr_devices.value()) {
let name = CString::try_from_fmt(fmt!("rnullb{}", i))?;
+ let submit_queues = if *module_parameters::use_per_node_hctx.value() != 0 {
+ kernel::num_online_nodes()
+ } else {
+ *module_parameters::submit_queues.value()
+ };
let disk = NullBlkDevice::new(NullBlkOptions {
name: &name,
block_size: *module_parameters::bs.value(),
@@ -114,7 +130,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
irq_mode: (*module_parameters::irqmode.value()).try_into()?,
completion_time: Delta::from_nanos(completion_time),
memory_backed: *module_parameters::memory_backed.value() != 0,
- submit_queues: *module_parameters::submit_queues.value(),
+ submit_queues,
})?;
disks.push(disk, GFP_KERNEL)?;
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 15/79] block: rnull: add `use_per_node_hctx` config option
2026-02-15 23:35 ` [PATCH 15/79] block: rnull: add `use_per_node_hctx` " Andreas Hindborg
@ 2026-03-16 10:43 ` Alice Ryhl
2026-03-16 11:01 ` Gary Guo
2026-03-16 13:57 ` Andreas Hindborg
0 siblings, 2 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:43 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:02AM +0100, Andreas Hindborg wrote:
> Add a configfs attribute to enable per-NUMA-node hardware contexts.
> When enabled, the driver creates one hardware queue per NUMA node
> instead of the default configuration.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
This and other patches make me think that module parameters should have
value() return a copy of the value (and require Copy). For non-copy
types, there can be a separate value_ref() method. You would avoid *so*
many asterisks by doing that.
> +configfs_attribute!(DeviceConfig, 8,
> + show: |this, page| show_field(
> + this.data.lock().submit_queues == kernel::num_online_nodes(), page
> + ),
> + store: |this, page| store_with_power_check(this, page, |this, page| {
> + let value = core::str::from_utf8(page)?
> + .trim()
> + .parse::<u8>()
> + .map_err(|_| kernel::error::code::EINVAL)?
> + != 0;
> +
> + if value {
> + this.data.lock().submit_queues *= kernel::num_online_nodes();
> + }
kstrtobool again. Also, this is *multiplying* the existing submit_queues
value by the number of NUMA nodes?
> + use_per_node_hctx: u8 {
> + default: 0,
> + description:
> + "Use per-node allocation for hardware context queues, 0-false, 1-true. Default: 0-false",
> + },
formatting (rustfmt ignores macros)
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread* Re: [PATCH 15/79] block: rnull: add `use_per_node_hctx` config option
2026-03-16 10:43 ` Alice Ryhl
@ 2026-03-16 11:01 ` Gary Guo
2026-03-16 13:57 ` Andreas Hindborg
1 sibling, 0 replies; 114+ messages in thread
From: Gary Guo @ 2026-03-16 11:01 UTC (permalink / raw)
To: Alice Ryhl, Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon Mar 16, 2026 at 10:43 AM GMT, Alice Ryhl wrote:
> On Mon, Feb 16, 2026 at 12:35:02AM +0100, Andreas Hindborg wrote:
>> Add a configfs attribute to enable per-NUMA-node hardware contexts.
>> When enabled, the driver creates one hardware queue per NUMA node
>> instead of the default configuration.
>>
>> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>
> This and other patches make me think that module parameters should have
> value() return a copy of the value (and require Copy). For non-copy
> types, there can be a separate value_ref() method. You would avoid *so*
> many asterisks by doing that.
It's also the sensible thing to do if we're going to add modifiable
module_params in the future.
Best,
Gary
>
>> +configfs_attribute!(DeviceConfig, 8,
>> + show: |this, page| show_field(
>> + this.data.lock().submit_queues == kernel::num_online_nodes(), page
>> + ),
>> + store: |this, page| store_with_power_check(this, page, |this, page| {
>> + let value = core::str::from_utf8(page)?
>> + .trim()
>> + .parse::<u8>()
>> + .map_err(|_| kernel::error::code::EINVAL)?
>> + != 0;
>> +
>> + if value {
>> + this.data.lock().submit_queues *= kernel::num_online_nodes();
>> + }
>
> kstrtobool again. Also, this is *multiplying* the existing submit_queues
> value by the number of NUMA nodes?
>
>> + use_per_node_hctx: u8 {
>> + default: 0,
>> + description:
>> + "Use per-node allocation for hardware context queues, 0-false, 1-true. Default: 0-false",
>> + },
>
> formatting (rustfmt ignores macros)
>
> Alice
^ permalink raw reply [flat|nested] 114+ messages in thread* Re: [PATCH 15/79] block: rnull: add `use_per_node_hctx` config option
2026-03-16 10:43 ` Alice Ryhl
2026-03-16 11:01 ` Gary Guo
@ 2026-03-16 13:57 ` Andreas Hindborg
2026-03-16 14:02 ` Miguel Ojeda
2026-03-16 14:05 ` Alice Ryhl
1 sibling, 2 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-03-16 13:57 UTC (permalink / raw)
To: Alice Ryhl
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
"Alice Ryhl" <aliceryhl@google.com> writes:
> On Mon, Feb 16, 2026 at 12:35:02AM +0100, Andreas Hindborg wrote:
>> Add a configfs attribute to enable per-NUMA-node hardware contexts.
>> When enabled, the driver creates one hardware queue per NUMA node
>> instead of the default configuration.
>>
>> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>
> This and other patches make me think that module parameters should have
> value() return a copy of the value (and require Copy). For non-copy
> types, there can be a separate value_ref() method. You would avoid *so*
> many asterisks by doing that.
Makes sense, I'll send a patch.
>
>> +configfs_attribute!(DeviceConfig, 8,
>> + show: |this, page| show_field(
>> + this.data.lock().submit_queues == kernel::num_online_nodes(), page
>> + ),
>> + store: |this, page| store_with_power_check(this, page, |this, page| {
>> + let value = core::str::from_utf8(page)?
>> + .trim()
>> + .parse::<u8>()
>> + .map_err(|_| kernel::error::code::EINVAL)?
>> + != 0;
>> +
>> + if value {
>> + this.data.lock().submit_queues *= kernel::num_online_nodes();
>> + }
>
> kstrtobool again. Also, this is *multiplying* the existing submit_queues
> value by the number of NUMA nodes?
Yea, that is not right. Astrisk should be deref on the other side of the
left hand expression.
>
>> + use_per_node_hctx: u8 {
>> + default: 0,
>> + description:
>> + "Use per-node allocation for hardware context queues, 0-false, 1-true. Default: 0-false",
>> + },
>
> formatting (rustfmt ignores macros)
This is intentional. The line gets too long if I pull it up, and I don't
think I can break the string in any way. I think it would require
changes to the module parameter macro.
Best regards,
Andreas Hindborg
^ permalink raw reply [flat|nested] 114+ messages in thread* Re: [PATCH 15/79] block: rnull: add `use_per_node_hctx` config option
2026-03-16 13:57 ` Andreas Hindborg
@ 2026-03-16 14:02 ` Miguel Ojeda
2026-03-16 14:05 ` Alice Ryhl
1 sibling, 0 replies; 114+ messages in thread
From: Miguel Ojeda @ 2026-03-16 14:02 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Alice Ryhl, Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Mar 16, 2026 at 2:58 PM Andreas Hindborg <a.hindborg@kernel.org> wrote:
>
> This is intentional. The line gets too long if I pull it up, and I don't
Do you mean you don't want to go over the limit or, otherwise, that
something else complains?
i.e. the limit is not a hard requirement -- exceptions can be made
where reasonable (as long as `rustfmt` is clean), and moving the line
to an odd position doesn't sound worth it.
Cheers,
Miguel
^ permalink raw reply [flat|nested] 114+ messages in thread
* Re: [PATCH 15/79] block: rnull: add `use_per_node_hctx` config option
2026-03-16 13:57 ` Andreas Hindborg
2026-03-16 14:02 ` Miguel Ojeda
@ 2026-03-16 14:05 ` Alice Ryhl
1 sibling, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 14:05 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Mar 16, 2026 at 02:57:47PM +0100, Andreas Hindborg wrote:
> "Alice Ryhl" <aliceryhl@google.com> writes:
>
> > On Mon, Feb 16, 2026 at 12:35:02AM +0100, Andreas Hindborg wrote:
> >> Add a configfs attribute to enable per-NUMA-node hardware contexts.
> >> When enabled, the driver creates one hardware queue per NUMA node
> >> instead of the default configuration.
> >>
> >> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> >
> > This and other patches make me think that module parameters should have
> > value() return a copy of the value (and require Copy). For non-copy
> > types, there can be a separate value_ref() method. You would avoid *so*
> > many asterisks by doing that.
>
> Makes sense, I'll send a patch.
Nice!
> >> + use_per_node_hctx: u8 {
> >> + default: 0,
> >> + description:
> >> + "Use per-node allocation for hardware context queues, 0-false, 1-true. Default: 0-false",
> >> + },
> >
> > formatting (rustfmt ignores macros)
>
> This is intentional. The line gets too long if I pull it up, and I don't
> think I can break the string in any way. I think it would require
> changes to the module parameter macro.
Just keep the wrong line. Checkpatch will complain, but it's standard to
ignore that checkpatch warning in C code for long strings to keep them
greppable, so I think it's fine here too.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 16/79] block: rust: allow specifying home node when constructing `TagSet`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (14 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 15/79] block: rnull: add `use_per_node_hctx` " Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:46 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 17/79] block: rnull: allow specifying the home numa node Andreas Hindborg
` (62 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a `numa_node` parameter to `TagSet::new` to specify the home NUMA
node for tag set allocations. This allows drivers to optimize memory
placement for NUMA systems.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 5 ++++-
rust/kernel/block/mq.rs | 5 ++++-
rust/kernel/block/mq/tag_set.rs | 3 ++-
3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 990dfcf95c9de..278f75d886fd9 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -176,7 +176,10 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
mq::tag_set::Flags::default()
};
- let tagset = Arc::pin_init(TagSet::new(submit_queues, 256, 1, flags), GFP_KERNEL)?;
+ let tagset = Arc::pin_init(
+ TagSet::new(submit_queues, 256, 1, bindings::NUMA_NO_NODE, flags),
+ GFP_KERNEL,
+ )?;
let queue_data = Box::pin_init(
pin_init!(QueueData {
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 76e790cdb1f8f..d3957f2fb1a66 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -57,6 +57,7 @@
//!
//! ```rust
//! use kernel::{
+//! bindings,
//! block::mq::{self, *},
//! new_mutex,
//! prelude::*,
@@ -92,7 +93,9 @@
//! }
//!
//! let tagset: Arc<TagSet<MyBlkDevice>> =
-//! Arc::pin_init(TagSet::new(1, 256, 1, mq::tag_set::Flags::default()), GFP_KERNEL)?;
+//! Arc::pin_init(
+//! TagSet::new(1, 256, 1, bindings::NUMA_NO_NODE, mq::tag_set::Flags::default()),
+//! GFP_KERNEL)?;
//! let mut disk = gen_disk::GenDiskBuilder::new()
//! .capacity_sectors(4096)
//! .build(fmt!("myblk"), tagset, ())?;
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index af214f7dd0c10..e9b36d6329b9b 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -41,6 +41,7 @@ pub fn new(
nr_hw_queues: u32,
num_tags: u32,
num_maps: u32,
+ numa_node: i32,
flags: Flags,
) -> impl PinInit<Self, error::Error> {
// SAFETY: `blk_mq_tag_set` only contains integers and pointers, which
@@ -53,7 +54,7 @@ pub fn new(
ops: OperationsVTable::<T>::build(),
nr_hw_queues,
timeout: 0, // 0 means default which is 30Hz in C
- numa_node: bindings::NUMA_NO_NODE,
+ numa_node,
queue_depth: num_tags,
cmd_size,
flags: flags.into_inner(),
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 16/79] block: rust: allow specifying home node when constructing `TagSet`
2026-02-15 23:35 ` [PATCH 16/79] block: rust: allow specifying home node when constructing `TagSet` Andreas Hindborg
@ 2026-03-16 10:46 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:46 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:03AM +0100, Andreas Hindborg wrote:
> Add a `numa_node` parameter to `TagSet::new` to specify the home NUMA
> node for tag set allocations. This allows drivers to optimize memory
> placement for NUMA systems.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
We already have a NumaNode type, which you should probably use instead
of raw integers.
Otherwise this looks ok.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 17/79] block: rnull: allow specifying the home numa node
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (15 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 16/79] block: rust: allow specifying home node when constructing `TagSet` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 18/79] block: rust: add Request::sectors() method Andreas Hindborg
` (61 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a configfs attribute to specify the NUMA node for rnull tag set
and CPU map allocations. This allows testing NUMA-aware block device
behavior and optimizing memory placement for specific hardware
configurations.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 19 +++++++++++++++++++
drivers/block/rnull/rnull.rs | 18 ++++++++++++++++--
2 files changed, 35 insertions(+), 2 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index b05bfc23090c2..fe00617d2b679 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -5,6 +5,7 @@
THIS_MODULE, //
};
use kernel::{
+ bindings,
block::mq::gen_disk::{
GenDisk,
GenDiskBuilder, //
@@ -92,6 +93,7 @@ fn make_group(
memory_backed: 6,
submit_queues: 7,
use_per_node_hctx: 8,
+ home_node: 9,
],
};
@@ -111,6 +113,7 @@ fn make_group(
name: name.try_into()?,
memory_backed: false,
submit_queues: 1,
+ home_node: bindings::NUMA_NO_NODE,
}),
}),
core::iter::empty(),
@@ -167,6 +170,7 @@ struct DeviceConfigInner {
disk: Option<GenDisk<NullBlkDevice>>,
memory_backed: bool,
submit_queues: u32,
+ home_node: i32,
}
#[vtable]
@@ -199,6 +203,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
completion_time: guard.completion_time,
memory_backed: guard.memory_backed,
submit_queues: guard.submit_queues,
+ home_node: guard.home_node,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -302,3 +307,17 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
Ok(())
})
);
+
+configfs_simple_field!(
+ DeviceConfig,
+ 9,
+ home_node,
+ i32,
+ check | value | {
+ if value == 0 || value >= kernel::num_online_nodes().try_into()? {
+ Err(kernel::error::code::EINVAL)
+ } else {
+ Ok(())
+ }
+ }
+);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 278f75d886fd9..fb3ce272d5bec 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -20,7 +20,10 @@
TagSet, //
},
},
- error::Result,
+ error::{
+ code,
+ Result, //
+ },
new_mutex,
new_xarray,
page::SafePage,
@@ -95,6 +98,10 @@
description:
"Use per-node allocation for hardware context queues, 0-false, 1-true. Default: 0-false",
},
+ home_node: i32 {
+ default: -1,
+ description: "Home node for the device. Default: -1 (no node)",
+ },
},
}
@@ -131,6 +138,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
completion_time: Delta::from_nanos(completion_time),
memory_backed: *module_parameters::memory_backed.value() != 0,
submit_queues,
+ home_node: *module_parameters::home_node.value(),
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -154,6 +162,7 @@ struct NullBlkOptions<'a> {
completion_time: Delta,
memory_backed: bool,
submit_queues: u32,
+ home_node: i32,
}
struct NullBlkDevice;
@@ -168,6 +177,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
completion_time,
memory_backed,
submit_queues,
+ home_node,
} = options;
let flags = if memory_backed {
@@ -176,8 +186,12 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
mq::tag_set::Flags::default()
};
+ if home_node > kernel::num_online_nodes().try_into()? {
+ return Err(code::EINVAL);
+ }
+
let tagset = Arc::pin_init(
- TagSet::new(submit_queues, 256, 1, bindings::NUMA_NO_NODE, flags),
+ TagSet::new(submit_queues, 256, 1, home_node, flags),
GFP_KERNEL,
)?;
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 18/79] block: rust: add Request::sectors() method
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (16 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 17/79] block: rnull: allow specifying the home numa node Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:48 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 19/79] block: rust: mq: add max_hw_discard_sectors support to GenDiskBuilder Andreas Hindborg
` (60 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a new method to get the size of a request in number of sectors.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 0dd329ae93dfc..9d11ae5651983 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -144,6 +144,13 @@ pub fn sector(&self) -> usize {
unsafe { (*self.0.get()).__sector as usize }
}
+ /// Get the size of the request in number of sectors.
+ #[inline(always)]
+ pub fn sectors(&self) -> usize {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
+ (unsafe { (*self.0.get()).__data_len as usize }) >> crate::block::SECTOR_SHIFT
+ }
+
/// Return a pointer to the [`RequestDataWrapper`] stored in the private area
/// of the request structure.
///
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 18/79] block: rust: add Request::sectors() method
2026-02-15 23:35 ` [PATCH 18/79] block: rust: add Request::sectors() method Andreas Hindborg
@ 2026-03-16 10:48 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:48 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:05AM +0100, Andreas Hindborg wrote:
> Add a new method to get the size of a request in number of sectors.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 19/79] block: rust: mq: add max_hw_discard_sectors support to GenDiskBuilder
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (17 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 18/79] block: rust: add Request::sectors() method Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:50 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 20/79] block: rnull: add discard support Andreas Hindborg
` (59 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for configuring the maximum hardware discard sectors
through GenDiskBuilder. This allows block devices to specify their
discard/trim capabilities.
Setting this value to 0 (the default) indicates that discard is not
supported by the device. Non-zero values specify the maximum number
of sectors that can be discarded in a single operation.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/gen_disk.rs | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 1ce815c8cdab0..75968d6a57639 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -25,6 +25,7 @@ pub struct GenDiskBuilder {
logical_block_size: u32,
physical_block_size: u32,
capacity_sectors: u64,
+ max_hw_discard_sectors: u32,
}
impl Default for GenDiskBuilder {
@@ -34,6 +35,7 @@ fn default() -> Self {
logical_block_size: bindings::PAGE_SIZE as u32,
physical_block_size: bindings::PAGE_SIZE as u32,
capacity_sectors: 0,
+ max_hw_discard_sectors: 0,
}
}
}
@@ -94,6 +96,16 @@ pub fn capacity_sectors(mut self, capacity: u64) -> Self {
self
}
+ /// Set the maximum amount of sectors the underlying hardware device can
+ /// discard/trim in a single operation.
+ ///
+ /// Setting 0 (default) here will cause the disk to report discard not
+ /// supported.
+ pub fn max_hw_discard_sectors(mut self, max_hw_discard_sectors: u32) -> Self {
+ self.max_hw_discard_sectors = max_hw_discard_sectors;
+ self
+ }
+
/// Build a new `GenDisk` and add it to the VFS.
pub fn build<T: Operations>(
self,
@@ -112,6 +124,7 @@ pub fn build<T: Operations>(
lim.logical_block_size = self.logical_block_size;
lim.physical_block_size = self.physical_block_size;
+ lim.max_hw_discard_sectors = self.max_hw_discard_sectors;
if self.rotational {
lim.features = bindings::BLK_FEAT_ROTATIONAL;
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 19/79] block: rust: mq: add max_hw_discard_sectors support to GenDiskBuilder
2026-02-15 23:35 ` [PATCH 19/79] block: rust: mq: add max_hw_discard_sectors support to GenDiskBuilder Andreas Hindborg
@ 2026-03-16 10:50 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:50 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:06AM +0100, Andreas Hindborg wrote:
> Add support for configuring the maximum hardware discard sectors
> through GenDiskBuilder. This allows block devices to specify their
> discard/trim capabilities.
>
> Setting this value to 0 (the default) indicates that discard is not
> supported by the device. Non-zero values specify the maximum number
> of sectors that can be discarded in a single operation.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
If 0 is a special value, then it could be slightly cleaner to use
Option<NonNullU32> or even a custom enum
enum MaxHwDiscardSectors {
Unsupported,
Supported { max: NonNullU32, }
}
But I'm also ok with current design, so:
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 20/79] block: rnull: add discard support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (18 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 19/79] block: rust: mq: add max_hw_discard_sectors support to GenDiskBuilder Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:52 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 21/79] block: rust: add `NoDefaultScheduler` flag for `TagSet` Andreas Hindborg
` (58 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for discard operations to the rnull block driver:
- Add discard module parameter and configfs attribute.
- Set max_hw_discard_sectors when discard is enabled.
- Add sector occupancy tracking.
- Add discard handling that frees sectors and removes empty pages.
- Discard operations require memory backing to function.
The discard feature uses a bitmap to track which sectors in each page are
occupied, allowing cleanup of pages when they are empty.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 15 ++++++
drivers/block/rnull/rnull.rs | 115 +++++++++++++++++++++++++++++++++++-----
2 files changed, 116 insertions(+), 14 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index fe00617d2b679..4ec9be440105d 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -94,6 +94,7 @@ fn make_group(
submit_queues: 7,
use_per_node_hctx: 8,
home_node: 9,
+ discard: 10,
],
};
@@ -114,6 +115,7 @@ fn make_group(
memory_backed: false,
submit_queues: 1,
home_node: bindings::NUMA_NO_NODE,
+ discard: false,
}),
}),
core::iter::empty(),
@@ -171,6 +173,7 @@ struct DeviceConfigInner {
memory_backed: bool,
submit_queues: u32,
home_node: i32,
+ discard: bool,
}
#[vtable]
@@ -204,6 +207,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
memory_backed: guard.memory_backed,
submit_queues: guard.submit_queues,
home_node: guard.home_node,
+ discard: guard.discard,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -321,3 +325,14 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
);
+
+configfs_attribute!(DeviceConfig, 10,
+ show: |this, page| show_field(this.data.lock().discard, page),
+ store: |this, page| store_with_power_check(this, page, |this, page| {
+ if !this.data.lock().memory_backed {
+ return Err(EINVAL);
+ }
+ this.data.lock().discard = kstrtobool_bytes(page)?;
+ Ok(())
+ })
+);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index fb3ce272d5bec..d1fb5fbc0c0be 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -19,14 +19,19 @@
Operations,
TagSet, //
},
+ SECTOR_MASK, SECTOR_SHIFT,
},
error::{
code,
Result, //
},
+ ffi,
new_mutex,
new_xarray,
- page::SafePage,
+ page::{
+ SafePage, //
+ PAGE_SIZE,
+ },
pr_info,
prelude::*,
str::CString,
@@ -102,6 +107,11 @@
default: -1,
description: "Home node for the device. Default: -1 (no node)",
},
+ discard: u8 {
+ default: 0,
+ description:
+ "Support discard operations (requires memory-backed null_blk device). Default: false",
+ },
},
}
@@ -139,6 +149,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
memory_backed: *module_parameters::memory_backed.value() != 0,
submit_queues,
home_node: *module_parameters::home_node.value(),
+ discard: *module_parameters::discard.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -163,6 +174,7 @@ struct NullBlkOptions<'a> {
memory_backed: bool,
submit_queues: u32,
home_node: i32,
+ discard: bool,
}
struct NullBlkDevice;
@@ -178,6 +190,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
memory_backed,
submit_queues,
home_node,
+ discard,
} = options;
let flags = if memory_backed {
@@ -201,22 +214,30 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
irq_mode,
completion_time,
memory_backed,
+ block_size: block_size as usize,
}),
GFP_KERNEL,
)?;
- gen_disk::GenDiskBuilder::new()
+ let mut builder = gen_disk::GenDiskBuilder::new()
.capacity_sectors(capacity_mib << (20 - block::SECTOR_SHIFT))
.logical_block_size(block_size)?
.physical_block_size(block_size)?
- .rotational(rotational)
- .build(fmt!("{}", name.to_str()?), tagset, queue_data)
+ .rotational(rotational);
+
+ if memory_backed && discard {
+ builder = builder
+ // Max IO size is u32::MAX bytes
+ .max_hw_discard_sectors(ffi::c_uint::MAX >> block::SECTOR_SHIFT);
+ }
+
+ builder.build(fmt!("{}", name.to_str()?), tagset, queue_data)
}
#[inline(always)]
fn write(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
while !segment.is_empty() {
- let page = SafePage::alloc_page(GFP_NOIO)?;
+ let page = NullBlockPage::new()?;
let mut tree = tree.lock();
let page_idx = sector >> block::PAGE_SECTORS_SHIFT;
@@ -228,8 +249,10 @@ fn write(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
tree.get_mut(page_idx).unwrap()
};
+ page.set_occupied(sector);
let page_offset = (sector & block::SECTOR_MASK as usize) << block::SECTOR_SHIFT;
- sector += segment.copy_to_page(page, page_offset) >> block::SECTOR_SHIFT;
+ sector +=
+ segment.copy_to_page(page.page.get_pin_mut(), page_offset) >> block::SECTOR_SHIFT;
}
Ok(())
}
@@ -243,7 +266,7 @@ fn read(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
if let Some(page) = tree.get(idx) {
let page_offset = (sector & block::SECTOR_MASK as usize) << block::SECTOR_SHIFT;
- sector += segment.copy_from_page(page, page_offset) >> block::SECTOR_SHIFT;
+ sector += segment.copy_from_page(&page.page, page_offset) >> block::SECTOR_SHIFT;
} else {
sector += segment.zero_page() >> block::SECTOR_SHIFT;
}
@@ -252,6 +275,32 @@ fn read(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
Ok(())
}
+ fn discard(tree: &Tree, mut sector: usize, sectors: usize, block_size: usize) -> Result {
+ let mut remaining_bytes = sectors << SECTOR_SHIFT;
+ let mut tree = tree.lock();
+
+ while remaining_bytes > 0 {
+ let page_idx = sector >> block::PAGE_SECTORS_SHIFT;
+ let mut remove = false;
+ if let Some(page) = tree.get_mut(page_idx) {
+ page.set_free(sector);
+ if page.is_empty() {
+ remove = true;
+ }
+ }
+
+ if remove {
+ drop(tree.remove(page_idx))
+ }
+
+ let processed = remaining_bytes.min(block_size);
+ sector += processed >> SECTOR_SHIFT;
+ remaining_bytes -= processed;
+ }
+
+ Ok(())
+ }
+
#[inline(never)]
fn transfer(
command: bindings::req_op,
@@ -268,7 +317,40 @@ fn transfer(
}
}
-type TreeNode = Owned<SafePage>;
+const _CHEKC_STATUS_WIDTH: () = build_assert!((PAGE_SIZE >> SECTOR_SHIFT) <= 64);
+
+struct NullBlockPage {
+ page: Owned<SafePage>,
+ status: u64,
+}
+
+impl NullBlockPage {
+ fn new() -> Result<KBox<Self>> {
+ Ok(KBox::new(
+ Self {
+ page: SafePage::alloc_page(GFP_NOIO | __GFP_ZERO)?,
+ status: 0,
+ },
+ GFP_NOIO,
+ )?)
+ }
+
+ fn set_occupied(&mut self, sector: usize) {
+ let idx = sector & SECTOR_MASK as usize;
+ self.status |= 1 << idx;
+ }
+
+ fn set_free(&mut self, sector: usize) {
+ let idx = sector & SECTOR_MASK as usize;
+ self.status &= !(1 << idx);
+ }
+
+ fn is_empty(&self) -> bool {
+ self.status == 0
+ }
+}
+
+type TreeNode = KBox<NullBlockPage>;
type Tree = XArray<TreeNode>;
#[pin_data]
@@ -278,6 +360,7 @@ struct QueueData {
irq_mode: IRQMode,
completion_time: Delta,
memory_backed: bool,
+ block_size: usize,
}
#[pin_data]
@@ -327,12 +410,16 @@ fn queue_rq(
let command = rq.command();
let mut sector = rq.sector();
- for bio in rq.bio_iter_mut() {
- let segment_iter = bio.segment_iter();
- for segment in segment_iter {
- let length = segment.len();
- Self::transfer(command, tree, sector, segment)?;
- sector += length as usize >> block::SECTOR_SHIFT;
+ if command == bindings::req_op_REQ_OP_DISCARD {
+ Self::discard(tree, sector, rq.sectors(), queue_data.block_size)?;
+ } else {
+ for bio in rq.bio_iter_mut() {
+ let segment_iter = bio.segment_iter();
+ for segment in segment_iter {
+ let length = segment.len();
+ Self::transfer(command, tree, sector, segment)?;
+ sector += length as usize >> block::SECTOR_SHIFT;
+ }
}
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 20/79] block: rnull: add discard support
2026-02-15 23:35 ` [PATCH 20/79] block: rnull: add discard support Andreas Hindborg
@ 2026-03-16 10:52 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:52 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:07AM +0100, Andreas Hindborg wrote:
> +configfs_attribute!(DeviceConfig, 10,
> + show: |this, page| show_field(this.data.lock().discard, page),
> + store: |this, page| store_with_power_check(this, page, |this, page| {
> + if !this.data.lock().memory_backed {
> + return Err(EINVAL);
> + }
> + this.data.lock().discard = kstrtobool_bytes(page)?;
Similar to the race I mentioned earlier with store_with_power_check(),
this is also a TOCTOU race.
> + discard: u8 {
> + default: 0,
> + description:
> + "Support discard operations (requires memory-backed null_blk device). Default: false",
> + },
kstrtobool again here...
> -type TreeNode = Owned<SafePage>;
> +const _CHEKC_STATUS_WIDTH: () = build_assert!((PAGE_SIZE >> SECTOR_SHIFT) <= 64);
Use static_assert! or assert! here.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 21/79] block: rust: add `NoDefaultScheduler` flag for `TagSet`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (19 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 20/79] block: rnull: add discard support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:53 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 22/79] block: rnull: add no_sched module parameter and configfs attribute Andreas Hindborg
` (57 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a flag that maps to the BLK_MQ_F_NO_SCHED_BY_DEFAULT. This flag selects
the 'none' scheduler during queue registration in case of a single hwq or
shared hwqs instead of 'mq-deadline'.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/tag_set/flags.rs | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/rust/kernel/block/mq/tag_set/flags.rs b/rust/kernel/block/mq/tag_set/flags.rs
index 768db938b9a95..1fca4fcb4dd20 100644
--- a/rust/kernel/block/mq/tag_set/flags.rs
+++ b/rust/kernel/block/mq/tag_set/flags.rs
@@ -15,5 +15,9 @@ pub enum Flag {
/// processing IO. When this flag is not set, IO is processed in atomic
/// context. When this flag is set, IO is processed in process context.
Blocking = bindings::BLK_MQ_F_BLOCKING,
+
+ /// Select 'none' during queue registration in case of a single hwq or shared
+ /// hwqs instead of 'mq-deadline'.
+ NoDefaultScheduler = bindings::BLK_MQ_F_NO_SCHED_BY_DEFAULT,
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 21/79] block: rust: add `NoDefaultScheduler` flag for `TagSet`
2026-02-15 23:35 ` [PATCH 21/79] block: rust: add `NoDefaultScheduler` flag for `TagSet` Andreas Hindborg
@ 2026-03-16 10:53 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:53 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:08AM +0100, Andreas Hindborg wrote:
> Add a flag that maps to the BLK_MQ_F_NO_SCHED_BY_DEFAULT. This flag selects
> the 'none' scheduler during queue registration in case of a single hwq or
> shared hwqs instead of 'mq-deadline'.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Can be squashed into next patch.
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 22/79] block: rnull: add no_sched module parameter and configfs attribute
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (20 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 21/79] block: rust: add `NoDefaultScheduler` flag for `TagSet` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:54 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 23/79] block: rust: change sector type from usize to u64 Andreas Hindborg
` (56 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for disabling the default IO scheduler by adding:
- no_sched module parameter to control scheduler selection at device
creation.
- no_sched configfs attribute (ID 11) for runtime configuration.
- Use of NO_DEFAULT_SCHEDULER flag when no_sched is enabled.
This allows bypassing the default 'mq-deadline' scheduler and using 'none'
instead, which can improve performance for certain workloads. The flag
selection logic is updated to use compound assignment operators for better
readability.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 31 +++++++++++++++++++++++++++++++
drivers/block/rnull/rnull.rs | 25 ++++++++++++++++++-------
2 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 4ec9be440105d..18e32a87673aa 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -95,6 +95,7 @@ fn make_group(
use_per_node_hctx: 8,
home_node: 9,
discard: 10,
+ no_sched:11,
],
};
@@ -116,6 +117,7 @@ fn make_group(
submit_queues: 1,
home_node: bindings::NUMA_NO_NODE,
discard: false,
+ no_sched: false,
}),
}),
core::iter::empty(),
@@ -174,6 +176,7 @@ struct DeviceConfigInner {
submit_queues: u32,
home_node: i32,
discard: bool,
+ no_sched: bool,
}
#[vtable]
@@ -208,6 +211,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
submit_queues: guard.submit_queues,
home_node: guard.home_node,
discard: guard.discard,
+ no_sched: guard.no_sched,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -336,3 +340,30 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
Ok(())
})
);
+
+#[vtable]
+impl configfs::AttributeOperations<11> for DeviceConfig {
+ type Data = DeviceConfig;
+
+ fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+ let mut writer = kernel::str::Formatter::new(page);
+
+ if this.data.lock().no_sched {
+ writer.write_str("1\n")?;
+ } else {
+ writer.write_str("0\n")?;
+ }
+
+ Ok(writer.bytes_written())
+ }
+
+ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
+ if this.data.lock().powered {
+ return Err(EBUSY);
+ }
+
+ this.data.lock().no_sched = kstrtobool_bytes(page)?;
+
+ Ok(())
+ }
+}
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index d1fb5fbc0c0be..9a301b06fc5e0 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -29,8 +29,8 @@
new_mutex,
new_xarray,
page::{
- SafePage, //
- PAGE_SIZE,
+ SafePage,
+ PAGE_SIZE, //
},
pr_info,
prelude::*,
@@ -112,6 +112,10 @@
description:
"Support discard operations (requires memory-backed null_blk device). Default: false",
},
+ no_sched: u8 {
+ default: 0,
+ description: "No IO scheduler",
+ },
},
}
@@ -150,6 +154,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
submit_queues,
home_node: *module_parameters::home_node.value(),
discard: *module_parameters::discard.value() != 0,
+ no_sched: *module_parameters::no_sched.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -175,6 +180,7 @@ struct NullBlkOptions<'a> {
submit_queues: u32,
home_node: i32,
discard: bool,
+ no_sched: bool,
}
struct NullBlkDevice;
@@ -191,13 +197,18 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
submit_queues,
home_node,
discard,
+ no_sched,
} = options;
- let flags = if memory_backed {
- mq::tag_set::Flag::Blocking.into()
- } else {
- mq::tag_set::Flags::default()
- };
+ let mut flags = mq::tag_set::Flags::default();
+
+ if memory_backed {
+ flags |= mq::tag_set::Flag::Blocking;
+ }
+
+ if no_sched {
+ flags |= mq::tag_set::Flag::NoDefaultScheduler;
+ }
if home_node > kernel::num_online_nodes().try_into()? {
return Err(code::EINVAL);
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 22/79] block: rnull: add no_sched module parameter and configfs attribute
2026-02-15 23:35 ` [PATCH 22/79] block: rnull: add no_sched module parameter and configfs attribute Andreas Hindborg
@ 2026-03-16 10:54 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:54 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:09AM +0100, Andreas Hindborg wrote:
> Add support for disabling the default IO scheduler by adding:
> - no_sched module parameter to control scheduler selection at device
> creation.
> - no_sched configfs attribute (ID 11) for runtime configuration.
> - Use of NO_DEFAULT_SCHEDULER flag when no_sched is enabled.
>
> This allows bypassing the default 'mq-deadline' scheduler and using 'none'
> instead, which can improve performance for certain workloads. The flag
> selection logic is updated to use compound assignment operators for better
> readability.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> +#[vtable]
> +impl configfs::AttributeOperations<11> for DeviceConfig {
> + type Data = DeviceConfig;
> +
> + fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> + let mut writer = kernel::str::Formatter::new(page);
> +
> + if this.data.lock().no_sched {
> + writer.write_str("1\n")?;
> + } else {
> + writer.write_str("0\n")?;
> + }
> +
> + Ok(writer.bytes_written())
> + }
> +
> + fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> + if this.data.lock().powered {
> + return Err(EBUSY);
> + }
> +
> + this.data.lock().no_sched = kstrtobool_bytes(page)?;
> +
> + Ok(())
> + }
Not using your fancy macro. Also, TOCTOU.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 23/79] block: rust: change sector type from usize to u64
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (21 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 22/79] block: rnull: add no_sched module parameter and configfs attribute Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 10:56 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 24/79] block: rust: add `BadBlocks` for bad block tracking Andreas Hindborg
` (55 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Change the `sector()` and `sectors()` methods in `Request` to return
`u64` and `u32` respectively instead of `usize`. This matches the
underlying kernel types.
Update rnull driver to handle the new sector types with appropriate
casting throughout the read, write, and discard operations.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 49 +++++++++++++++++++++--------------------
rust/kernel/block/mq/request.rs | 8 +++----
2 files changed, 29 insertions(+), 28 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 9a301b06fc5e0..b0008e2f9c398 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -225,7 +225,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
irq_mode,
completion_time,
memory_backed,
- block_size: block_size as usize,
+ block_size: block_size.into(),
}),
GFP_KERNEL,
)?;
@@ -246,54 +246,55 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
}
#[inline(always)]
- fn write(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
+ fn write(tree: &Tree, mut sector: u64, mut segment: Segment<'_>) -> Result {
while !segment.is_empty() {
let page = NullBlockPage::new()?;
let mut tree = tree.lock();
let page_idx = sector >> block::PAGE_SECTORS_SHIFT;
- let page = if let Some(page) = tree.get_mut(page_idx) {
+ let page = if let Some(page) = tree.get_mut(page_idx as usize) {
page
} else {
- tree.store(page_idx, page, GFP_NOIO)?;
- tree.get_mut(page_idx).unwrap()
+ tree.store(page_idx as usize, page, GFP_NOIO)?;
+ tree.get_mut(page_idx as usize).unwrap()
};
page.set_occupied(sector);
- let page_offset = (sector & block::SECTOR_MASK as usize) << block::SECTOR_SHIFT;
- sector +=
- segment.copy_to_page(page.page.get_pin_mut(), page_offset) >> block::SECTOR_SHIFT;
+ let page_offset = (sector & u64::from(block::SECTOR_MASK)) << block::SECTOR_SHIFT;
+ sector += segment.copy_to_page(page.page.get_pin_mut(), page_offset as usize) as u64
+ >> block::SECTOR_SHIFT;
}
Ok(())
}
#[inline(always)]
- fn read(tree: &Tree, mut sector: usize, mut segment: Segment<'_>) -> Result {
+ fn read(tree: &Tree, mut sector: u64, mut segment: Segment<'_>) -> Result {
let tree = tree.lock();
while !segment.is_empty() {
let idx = sector >> block::PAGE_SECTORS_SHIFT;
- if let Some(page) = tree.get(idx) {
- let page_offset = (sector & block::SECTOR_MASK as usize) << block::SECTOR_SHIFT;
- sector += segment.copy_from_page(&page.page, page_offset) >> block::SECTOR_SHIFT;
+ if let Some(page) = tree.get(idx as usize) {
+ let page_offset = (sector & u64::from(block::SECTOR_MASK)) << block::SECTOR_SHIFT;
+ sector += segment.copy_from_page(&page.page, page_offset as usize) as u64
+ >> block::SECTOR_SHIFT;
} else {
- sector += segment.zero_page() >> block::SECTOR_SHIFT;
+ sector += segment.zero_page() as u64 >> block::SECTOR_SHIFT;
}
}
Ok(())
}
- fn discard(tree: &Tree, mut sector: usize, sectors: usize, block_size: usize) -> Result {
+ fn discard(tree: &Tree, mut sector: u64, sectors: u64, block_size: u64) -> Result {
let mut remaining_bytes = sectors << SECTOR_SHIFT;
let mut tree = tree.lock();
while remaining_bytes > 0 {
let page_idx = sector >> block::PAGE_SECTORS_SHIFT;
let mut remove = false;
- if let Some(page) = tree.get_mut(page_idx) {
+ if let Some(page) = tree.get_mut(page_idx as usize) {
page.set_free(sector);
if page.is_empty() {
remove = true;
@@ -301,7 +302,7 @@ fn discard(tree: &Tree, mut sector: usize, sectors: usize, block_size: usize) ->
}
if remove {
- drop(tree.remove(page_idx))
+ drop(tree.remove(page_idx as usize))
}
let processed = remaining_bytes.min(block_size);
@@ -316,7 +317,7 @@ fn discard(tree: &Tree, mut sector: usize, sectors: usize, block_size: usize) ->
fn transfer(
command: bindings::req_op,
tree: &Tree,
- sector: usize,
+ sector: u64,
segment: Segment<'_>,
) -> Result {
match command {
@@ -346,13 +347,13 @@ fn new() -> Result<KBox<Self>> {
)?)
}
- fn set_occupied(&mut self, sector: usize) {
- let idx = sector & SECTOR_MASK as usize;
+ fn set_occupied(&mut self, sector: u64) {
+ let idx = sector & u64::from(SECTOR_MASK);
self.status |= 1 << idx;
}
- fn set_free(&mut self, sector: usize) {
- let idx = sector & SECTOR_MASK as usize;
+ fn set_free(&mut self, sector: u64) {
+ let idx = sector & u64::from(SECTOR_MASK);
self.status &= !(1 << idx);
}
@@ -371,7 +372,7 @@ struct QueueData {
irq_mode: IRQMode,
completion_time: Delta,
memory_backed: bool,
- block_size: usize,
+ block_size: u64,
}
#[pin_data]
@@ -422,14 +423,14 @@ fn queue_rq(
let mut sector = rq.sector();
if command == bindings::req_op_REQ_OP_DISCARD {
- Self::discard(tree, sector, rq.sectors(), queue_data.block_size)?;
+ Self::discard(tree, sector, rq.sectors().into(), queue_data.block_size)?;
} else {
for bio in rq.bio_iter_mut() {
let segment_iter = bio.segment_iter();
for segment in segment_iter {
let length = segment.len();
Self::transfer(command, tree, sector, segment)?;
- sector += length as usize >> block::SECTOR_SHIFT;
+ sector += u64::from(length) >> block::SECTOR_SHIFT;
}
}
}
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 9d11ae5651983..8fe7e126c522a 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -139,16 +139,16 @@ pub fn bio_iter_mut<'a>(self: &'a mut Owned<Self>) -> BioIterator<'a> {
/// Get the target sector for the request.
#[inline(always)]
- pub fn sector(&self) -> usize {
+ pub fn sector(&self) -> u64 {
// SAFETY: By type invariant of `Self`, `self.0` is valid and live.
- unsafe { (*self.0.get()).__sector as usize }
+ unsafe { (*self.0.get()).__sector }
}
/// Get the size of the request in number of sectors.
#[inline(always)]
- pub fn sectors(&self) -> usize {
+ pub fn sectors(&self) -> u32 {
// SAFETY: By type invariant of `Self`, `self.0` is valid and live.
- (unsafe { (*self.0.get()).__data_len as usize }) >> crate::block::SECTOR_SHIFT
+ (unsafe { (*self.0.get()).__data_len }) >> crate::block::SECTOR_SHIFT
}
/// Return a pointer to the [`RequestDataWrapper`] stored in the private area
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 23/79] block: rust: change sector type from usize to u64
2026-02-15 23:35 ` [PATCH 23/79] block: rust: change sector type from usize to u64 Andreas Hindborg
@ 2026-03-16 10:56 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 10:56 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:10AM +0100, Andreas Hindborg wrote:
> Change the `sector()` and `sectors()` methods in `Request` to return
> `u64` and `u32` respectively instead of `usize`. This matches the
> underlying kernel types.
>
> Update rnull driver to handle the new sector types with appropriate
> casting throughout the read, write, and discard operations.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
This has lots of unchecked casts from u64 to usize, which could overflow
on 32-bit systems. Could use some CAST: comments or similar.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 24/79] block: rust: add `BadBlocks` for bad block tracking
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (22 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 23/79] block: rust: change sector type from usize to u64 Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 11:55 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 25/79] block: rust: mq: add Request::end() method for custom status codes Andreas Hindborg
` (54 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a safe Rust wrapper around the Linux kernel's badblocks infrastructure
to track and manage defective sectors on block devices. The BadBlocks type
provides methods to:
- Mark sectors as bad or good (set_bad/set_good)
- Check if sector ranges contain bad blocks (check)
- Automatically handle memory management with PinnedDrop
The implementation includes comprehensive documentation with examples for
block device drivers that need to avoid known bad sectors to maintain
data integrity. Bad blocks information is used by device drivers,
filesystem layers, and device management tools.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/bindings/bindings_helper.h | 1 +
rust/kernel/block.rs | 1 +
rust/kernel/block/badblocks.rs | 721 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 723 insertions(+)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index e0ba5c712c560..76b58c3fd1ff1 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -36,6 +36,7 @@
#include <drm/drm_ioctl.h>
#include <kunit/test.h>
#include <linux/auxiliary_bus.h>
+#include <linux/badblocks.h>
#include <linux/bitmap.h>
#include <linux/blk-mq.h>
#include <linux/blk_types.h>
diff --git a/rust/kernel/block.rs b/rust/kernel/block.rs
index 17de727bc1047..19236ab95227b 100644
--- a/rust/kernel/block.rs
+++ b/rust/kernel/block.rs
@@ -2,6 +2,7 @@
//! Types for working with the block layer.
+pub mod badblocks;
pub mod bio;
pub mod mq;
diff --git a/rust/kernel/block/badblocks.rs b/rust/kernel/block/badblocks.rs
new file mode 100644
index 0000000000000..a5fe0fde2e755
--- /dev/null
+++ b/rust/kernel/block/badblocks.rs
@@ -0,0 +1,721 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Bad blocks tracking for block devices.
+//!
+//! This module provides a safe Rust wrapper around the badblocks
+//! infrastructure, which is used to track and manage bad sectors on block
+//! devices. Bad blocks are sectors that cannot reliably store data and should
+//! be avoided during I/O operations.
+
+use core::ops::{Range, RangeBounds};
+
+use crate::{
+ error::to_result,
+ page::PAGE_SIZE,
+ prelude::*,
+ sync::atomic::{ordering, Atomic},
+ types::Opaque,
+};
+use pin_init::{pin_data, PinInit};
+
+/// A bad blocks tracker for managing defective sectors on a block device.
+///
+/// `BadBlocks` provides functionality to mark sectors as bad and check if
+/// ranges contain bad blocks. This is useful for some classes of drivers to
+/// maintain data integrity by avoiding known bad sectors.
+///
+/// # Storage Format
+///
+/// Bad blocks are stored in a compact format where each 64-bit entry contains:
+/// - **Sector offset** (54 bits): Starting sector of the bad range
+/// - **Length** (9 bits): Number of sectors (1-512) in the bad range
+/// - **Acknowledged flag** (1 bit): Whether the bad blocks have been acknowledged
+///
+/// The bad blocks tracker uses exactly one page ([`PAGE_SIZE`]) of memory to store
+/// bad block entries. This allows tracking up to `PAGE_SIZE/8` bad block ranges
+/// (typically 512 ranges on systems with 4KB pages).
+///
+/// # Locking
+///
+/// Operations on the structure is internally synchronized by a seqlock.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```rust
+/// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+/// # use kernel::prelude::*;
+///
+/// // Create a new bad blocks tracker
+/// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+///
+/// // Mark sectors 100-109 as bad (unacknowledged)
+/// bad_blocks.set_bad(100..110, false)?;
+///
+/// // Check if sector range 95-104 contains bad blocks
+/// match bad_blocks.check(95..105) {
+/// BlockStatus::None => pr_info!("No bad blocks found"),
+/// BlockStatus::Acknowledged(range) => pr_warn!("Acknowledged bad blocks: {:?}", range),
+/// BlockStatus::Unacknowledged(range) => pr_err!("Unacknowledged bad blocks: {:?}", range),
+/// }
+/// # Ok::<(), kernel::error::Error>(())
+/// ```
+/// # Invariants
+///
+/// - `self.blocks` is a valid `bindings::badblocks` struct.
+#[pin_data(PinnedDrop)]
+pub struct BadBlocks {
+ #[pin]
+ blocks: Opaque<bindings::badblocks>,
+}
+
+impl BadBlocks {
+ /// Creates a new bad blocks tracker.
+ ///
+ /// Initializes an empty bad blocks tracker that can manage defective sectors
+ /// on a block device. The tracker starts with no bad blocks recorded and
+ /// allocates a single page for storing bad block entries.
+ ///
+ /// # Returns
+ ///
+ /// Returns a [`PinInit`] that can be used to initialize a [`BadBlocks`] instance.
+ /// Initialization may fail with `ENOMEM` if memory allocation fails.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// // Create and initialize a bad blocks tracker
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // The tracker is ready to use with no bad blocks initially
+ /// match bad_blocks.check(0..100) {
+ /// BlockStatus::None => pr_info!("No bad blocks found initially"),
+ /// _ => unreachable!(),
+ /// }
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ pub fn new(enable: bool) -> impl PinInit<Self, Error> {
+ // INVARIANT: We initialize `self.blocks` below. If initialization fails, an error is
+ // returned.
+ try_pin_init!(Self {
+ blocks <- Opaque::try_ffi_init(|slot| {
+ // SAFETY: `slot` is a valid pointer to uninitialized memory
+ // allocated by the Opaque type. `badblocks_init` is safe to
+ // call with uninitialized memory.
+ to_result(unsafe {bindings::badblocks_init(slot, if enable {1} else {0})})
+ }),
+ })
+ }
+
+ fn shift_ref(&self) -> &Atomic<c_int> {
+ // SAFETY: By type invariant self.blocks is valid.
+ let ptr = unsafe { &raw const (*self.blocks.get()).shift };
+ // SAFETY: `shift` is only written by C code using atomic operations after initialization.
+ unsafe { Atomic::from_ptr(ptr.cast_mut().cast()) }
+ }
+
+ /// Enables the bad blocks tracker if it was previously disabled.
+ ///
+ /// Attempts to enable bad block tracking by transitioning the tracker from
+ /// a disabled state to an enabled state.
+ ///
+ /// # Behavior
+ ///
+ /// - If the tracker is disabled, it will be enabled.
+ /// - If the tracker is already enabled, this operation has no effect.
+ /// - The operation is atomic and thread-safe.
+ ///
+ /// # Usage
+ ///
+ /// Bad blocks trackers can be created in a disabled state and enabled later
+ /// when needed. This is useful for conditional bad block tracking or for
+ /// deferring activation until the device is fully initialized.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::BadBlocks;
+ /// # use kernel::prelude::*;
+ ///
+ /// // Create a disabled bad blocks tracker
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(false), GFP_KERNEL)?;
+ /// assert!(!bad_blocks.enabled());
+ ///
+ /// // Enable it when needed
+ /// bad_blocks.enable();
+ /// assert!(bad_blocks.enabled());
+ ///
+ /// // Subsequent enable calls have no effect
+ /// bad_blocks.enable();
+ /// assert!(bad_blocks.enabled());
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ pub fn enable(&self) {
+ let _ = self.shift_ref().cmpxchg(-1, 0, ordering::Relaxed);
+ }
+
+ /// Checks whether the bad blocks tracker is currently enabled.
+ ///
+ /// Returns `true` if bad block tracking is active, `false` if it is disabled.
+ /// When disabled, the tracker will not perform bad block checks or operations.
+ ///
+ /// # Returns
+ ///
+ /// - `true` - Bad block tracking is enabled and operational
+ /// - `false` - Bad block tracking is disabled
+ ///
+ /// # Thread Safety
+ ///
+ /// This method is thread-safe and uses atomic operations to check the
+ /// tracker's state without requiring external synchronization.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::BadBlocks;
+ /// # use kernel::prelude::*;
+ ///
+ /// // Create an enabled tracker
+ /// let enabled_tracker = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ /// assert!(enabled_tracker.enabled());
+ ///
+ /// // Create a disabled tracker
+ /// let disabled_tracker = KBox::pin_init(BadBlocks::new(false), GFP_KERNEL)?;
+ /// assert!(!disabled_tracker.enabled());
+ ///
+ /// // Enable and verify
+ /// disabled_tracker.enable();
+ /// assert!(disabled_tracker.enabled());
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ pub fn enabled(&self) -> bool {
+ self.shift_ref().load(ordering::Relaxed) >= 0
+ }
+
+ /// Marks a range of sectors as bad.
+ ///
+ /// Records a contiguous range of sectors as defective in the bad blocks tracker.
+ /// Bad sectors should be avoided during I/O operations to prevent data corruption.
+ /// The implementation may merge, split, or extend existing ranges as needed.
+ ///
+ /// # Parameters
+ ///
+ /// - `range` - The range of sectors to mark as bad. Each individual range is limited to 512
+ /// sectors maximum by the underlying implementation.
+ /// - `acknowledged` - Whether the bad blocks have been acknowledged to be bad. Acknowledged bad
+ /// blocks may be handled differently by some subsystems.
+ ///
+ /// # Acknowledgment Semantics
+ ///
+ /// - **Unacknowledged** (`acknowledged = false`): Newly discovered bad blocks that
+ /// need attention. These are often treated as errors by upper layers.
+ /// - **Acknowledged** (`acknowledged = true`): Blocks that have been confirmed bad. These may
+ /// be should be handled by remapping.
+ ///
+ /// # Range Management
+ ///
+ /// The implementation automatically:
+ /// - **Merges** adjacent or overlapping ranges with the same acknowledgment status
+ /// - **Splits** ranges when acknowledgment status differs
+ /// - **Extends** existing ranges when new bad blocks are adjacent
+ /// - **Limits** individual ranges to 512 sectors maximum (BB_MAX_LEN)
+ ///
+ /// Please see [C documentation] for details.
+ ///
+ /// # Performance
+ ///
+ /// Executes in O(n) time where n is number of entries in the bad block table.
+ ///
+ /// # Returns
+ ///
+ /// * `Ok(())` - Bad blocks were successfully recorded
+ /// * `Err(ENOMEM)` - Insufficient space in bad blocks table (table full)
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // Mark sectors 1000-1009 as bad (unacknowledged)
+ /// bad_blocks.set_bad(1000..1010, false)?;
+ ///
+ /// // Mark a single sector as bad and acknowledged
+ /// bad_blocks.set_bad(2000..2001, true)?;
+ ///
+ /// // Verify the bad blocks are recorded
+ /// assert!(matches!(bad_blocks.check(1000..1010), BlockStatus::Unacknowledged(_)));
+ /// assert!(matches!(bad_blocks.check(2000..2001), BlockStatus::Acknowledged(_)));
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ ///
+ /// Range merging behavior:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // Add adjacent ranges with same acknowledgment status
+ /// bad_blocks.set_bad(100..105, false)?; // Sectors 100-104
+ /// bad_blocks.set_bad(105..108, false)?; // Sectors 105-107
+ ///
+ /// // These will be merged into a single range 100-107
+ /// match bad_blocks.check(100..108) {
+ /// BlockStatus::Unacknowledged(range) => {
+ /// assert_eq!(range.start, 100);
+ /// assert_eq!(range.end, 108);
+ /// },
+ /// _ => panic!("Expected unacknowledged bad blocks"),
+ /// }
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ ///
+ /// Handling acknowledgment conflicts:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // Mark range as unacknowledged
+ /// bad_blocks.set_bad(200..210, false)?;
+ ///
+ /// // Acknowledge part of the range (will split)
+ /// bad_blocks.set_bad(205..208, true)?;
+ ///
+ /// // Now we have: unack[200-204], ack[205-207], unack[208-209]
+ /// assert!(matches!(bad_blocks.check(200..205), BlockStatus::Unacknowledged(_)));
+ /// assert!(matches!(bad_blocks.check(205..208), BlockStatus::Acknowledged(_)));
+ /// assert!(matches!(bad_blocks.check(208..210), BlockStatus::Unacknowledged(_)));
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ ///
+ /// [C documentation]: srctree/block/badblocks.c
+ pub fn set_bad(&self, range: impl RangeBounds<u64>, acknowledged: bool) -> Result {
+ let range = Self::range(range);
+
+ // SAFETY: By type invariant `self.blocks` is valid. The C function
+ // `badblocks_set` handles synchronization internally.
+ unsafe {
+ bindings::badblocks_set(
+ self.blocks.get(),
+ range.start,
+ range.end - range.start,
+ if acknowledged { 1 } else { 0 },
+ )
+ }
+ .then_some(())
+ .ok_or(ENOMEM)
+ }
+
+ /// Marks a range of sectors as good.
+ ///
+ /// Removes a contiguous range of sectors from the bad blocks tracker,
+ /// indicating that these sectors are now reliable for I/O operations.
+ /// This is typically used after bad sectors have been repaired, remapped,
+ /// or determined to be false positives.
+ ///
+ /// # Parameters
+ ///
+ /// - `range` - The range of sectors to mark as good.
+ ///
+ /// # Behavior
+ ///
+ /// The implementation handles various scenarios automatically:
+ /// - **Complete removal**: If the range exactly matches a bad block range, it's removed
+ /// entirely.
+ /// - **Partial removal**: If the range partially overlaps, the bad block range is split or
+ /// trimmed.
+ /// - **No effect**: If the range doesn't overlap any bad blocks, the operation succeeds without
+ /// changes.
+ /// - **Range splitting**: If the cleared range is in the middle of a bad block range, it may
+ /// split the range in two.
+ ///
+ /// # Performance
+ ///
+ /// Executes in O(n) time where n is the number of entries in the bad blocks table.
+ ///
+ /// # Returns
+ ///
+ /// * `Ok(())` - Sectors were successfully marked as good (or were already good)
+ /// * `Err(EINVAL)` - Operation failed (typically due to table constraints)
+ ///
+ /// # Examples
+ ///
+ /// Basic usage after repair:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // Mark some sectors as bad initially
+ /// bad_blocks.set_bad(100..110, false)?;
+ /// assert!(matches!(bad_blocks.check(100..110), BlockStatus::Unacknowledged(_)));
+ ///
+ /// // After successful repair, mark them as good
+ /// bad_blocks.set_good(100..110)?;
+ /// assert!(matches!(bad_blocks.check(100..110), BlockStatus::None));
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ ///
+ /// Partial clearing:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // Mark a large range as bad
+ /// bad_blocks.set_bad(200..220, false)?;
+ ///
+ /// // Clear only the middle portion
+ /// bad_blocks.set_good(205..215)?; // Clear sectors 205-214
+ ///
+ /// // Now we have bad blocks at the edges: 200-204 and 215-219
+ /// assert!(matches!(bad_blocks.check(200..205), BlockStatus::Unacknowledged(_)));
+ /// assert!(matches!(bad_blocks.check(205..215), BlockStatus::None));
+ /// assert!(matches!(bad_blocks.check(215..220), BlockStatus::Unacknowledged(_)));
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ ///
+ /// Safe clearing of potentially good sectors:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // It's safe to clear sectors that were never marked as bad
+ /// bad_blocks.set_good(1000..1100)?; // No-op, but succeeds
+ /// assert!(matches!(bad_blocks.check(1000..1100), BlockStatus::None));
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ pub fn set_good(&self, range: impl RangeBounds<u64>) -> Result {
+ let range = Self::range(range);
+ // SAFETY: By type invariant `self.blocks` is valid. The C function
+ // `badblocks_clear` handles synchronization internally.
+ unsafe {
+ bindings::badblocks_clear(self.blocks.get(), range.start, range.end - range.start)
+ }
+ .then_some(())
+ .ok_or(EINVAL)
+ }
+
+ // Transform a `RangeBounds` to start included end excluded range.
+ fn range(range: impl RangeBounds<u64>) -> Range<u64> {
+ let start = match range.start_bound() {
+ core::ops::Bound::Included(start) => *start,
+ core::ops::Bound::Excluded(start) => start + 1,
+ core::ops::Bound::Unbounded => u64::MIN,
+ };
+
+ let end = match range.end_bound() {
+ core::ops::Bound::Included(end) => end + 1,
+ core::ops::Bound::Excluded(end) => *end,
+ core::ops::Bound::Unbounded => u64::MAX,
+ };
+
+ start..end
+ }
+
+ /// Checks if a range of sectors contains any bad blocks.
+ ///
+ /// Examines the specified sector range to determine if it contains any sectors
+ /// that have been marked as bad. This is typically called before performing I/O
+ /// operations to avoid accessing defective sectors. The check uses seqlocks to
+ /// ensure consistent reads even under concurrent modifications.
+ ///
+ /// # Parameters
+ ///
+ /// - `range` - The range of sectors to check (supports any type implementing
+ /// `RangeBounds<u64>`).
+ ///
+ /// # Returns
+ ///
+ /// Returns a [`BlockStatus`] indicating the state of the checked range:
+ ///
+ /// - `BlockStatus::None` - No bad blocks found in the specified range.
+ /// - `BlockStatus::Acknowledged(range)` - Contains acknowledged bad blocks.
+ /// - `BlockStatus::Unacknowledged(range)` - Contains unacknowledged bad blocks.
+ ///
+ /// The returned range indicates the **first bad block range** encountered that
+ /// overlaps with the checked area. If multiple separate bad ranges exist, only
+ /// the first is reported.
+ ///
+ /// # Performance
+ ///
+ /// The check operation uses binary search on the sorted bad blocks table,
+ /// providing O(log n) lookup time where n is the number of bad block ranges.
+ ///
+ /// # Examples
+ ///
+ /// Basic checking:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // Initially no bad blocks
+ /// assert!(matches!(bad_blocks.check(0..1000), BlockStatus::None));
+ ///
+ /// // Mark some sectors as bad
+ /// bad_blocks.set_bad(100..110, false)?;
+ ///
+ /// // Check various ranges
+ /// match bad_blocks.check(90..120) {
+ /// BlockStatus::Unacknowledged(range) => {
+ /// assert_eq!(range.start, 100);
+ /// assert_eq!(range.end, 110);
+ /// pr_warn!("Found unacknowledged bad blocks: {}-{}", range.start, (range.end - 1));
+ /// },
+ /// _ => panic!("Expected bad blocks"),
+ /// }
+ ///
+ /// // Check range that doesn't overlap
+ /// assert!(matches!(bad_blocks.check(0..50), BlockStatus::None));
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ ///
+ /// Handling different acknowledgment states:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ ///
+ /// // Add both acknowledged and unacknowledged bad blocks
+ /// bad_blocks.set_bad(100..105, true)?; // Acknowledged
+ /// bad_blocks.set_bad(200..205, false)?; // Unacknowledged
+ ///
+ /// match bad_blocks.check(95..105) {
+ /// BlockStatus::Acknowledged(range) => {
+ /// pr_info!("Acknowledged bad blocks found, can potentially remap: {:?}", range);
+ /// // Continue with remapping logic
+ /// },
+ /// BlockStatus::Unacknowledged(range) => {
+ /// pr_err!("Unacknowledged bad blocks found, requires attention: {:?}", range);
+ /// // Handle as error condition
+ /// },
+ /// BlockStatus::None => {
+ /// // Safe to proceed with I/O
+ /// },
+ /// }
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ ///
+ /// Safe I/O operation pattern:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ /// # use core::ops::RangeBounds;
+ /// # fn perform_sector_read(range: impl RangeBounds<u64>) -> Result<()> { Ok(()) }
+ ///
+ /// fn safe_read_sectors(
+ /// bad_blocks: &BadBlocks,
+ /// range: impl RangeBounds<u64> + Clone
+ /// ) -> Result<()> {
+ /// // Check for bad blocks before attempting I/O
+ /// match bad_blocks.check(range.clone()) {
+ /// BlockStatus::None => {
+ /// // Safe to proceed with I/O operation - convert range to
+ /// // start/count for legacy function.
+ /// perform_sector_read(range)
+ /// },
+ /// BlockStatus::Acknowledged(range) => {
+ /// pr_warn!("I/O intersects acknowledged bad blocks: {:?}", range);
+ /// // Potentially remap or skip bad sectors
+ /// Err(EIO)
+ /// },
+ /// BlockStatus::Unacknowledged(range) => {
+ /// pr_err!("I/O intersects unacknowledged bad blocks: {:?}", range);
+ /// // Treat as serious error
+ /// Err(EIO)
+ /// },
+ /// }
+ /// }
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ pub fn check(&self, range: impl RangeBounds<u64>) -> BlockStatus {
+ let mut first_bad = 0;
+ let mut bad_count = 0;
+ let range = Self::range(range);
+
+ // SAFETY: By type invariant `self.blocks` is valid. `first_bad` and
+ // `bad_count` are valid mutable references The C function
+ // `badblocks_check` handles synchronization internally.
+ let ret = unsafe {
+ bindings::badblocks_check(
+ self.blocks.get(),
+ range.start,
+ range.end - range.start,
+ &mut first_bad,
+ &mut bad_count,
+ )
+ };
+
+ match ret {
+ 0 => BlockStatus::None,
+ 1 => BlockStatus::Acknowledged(first_bad..first_bad + bad_count),
+ -1 => BlockStatus::Unacknowledged(first_bad..first_bad + bad_count),
+ _ => {
+ debug_assert!(false, "Illegal return value from `badblocks_check`");
+ BlockStatus::None
+ }
+ }
+ }
+
+ /// Formats bad blocks information into a human-readable string.
+ ///
+ /// Exports the current bad blocks table to a text representation suitable
+ /// for display via sysfs. The output format shows each bad block range
+ /// with sector numbers and acknowledgment status.
+ ///
+ /// # Parameters
+ ///
+ /// - `page` - A page-sized buffer to write the formatted output into.
+ /// - `show_unacknowledged` - Whether to include unacknowledged bad blocks in output.
+ /// - `true`: Shows both acknowledged and unacknowledged bad blocks
+ /// - `false`: Shows only acknowledged bad blocks
+ ///
+ /// # Output Format
+ ///
+ /// The output consists of space-separated entries, each representing a bad block range:
+ /// - Format: `start_sector length [acknowledgment_status]`
+ /// - Acknowledged blocks: Just sector and length (e.g., "100 10")
+ /// - Unacknowledged blocks: Sector, length, and "u" suffix (e.g., "200 5 u")
+ ///
+ /// # Returns
+ ///
+ /// Returns the number of bytes written to the buffer, or a negative value on error.
+ /// The returned length can be used to extract the valid portion of the buffer.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```rust
+ /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+ /// # use kernel::prelude::*;
+ /// # use kernel::page::PAGE_SIZE;
+ ///
+ /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
+ /// let mut page = [0u8; PAGE_SIZE];
+ ///
+ /// // Add some bad blocks
+ /// bad_blocks.set_bad(100..110, true)?; // Acknowledged
+ /// bad_blocks.set_bad(200..205, false)?; // Unacknowledged
+ ///
+ /// // Show all bad blocks (including unacknowledged)
+ /// let len = bad_blocks.show(&mut page, true);
+ /// if len > 0 {
+ /// let output = core::str::from_utf8(&page[..len as usize]).unwrap_or("<invalid utf8>");
+ /// pr_info!("Bad blocks: {}", output);
+ /// // Output might be: "100 10 200 5 u"
+ /// }
+ /// # Ok::<(), kernel::error::Error>(())
+ /// ```
+ pub fn show(&self, page: &mut [u8; PAGE_SIZE], show_unacknowledged: bool) -> isize {
+ // SAFETY: By type invariant `self.blocks` is valid. The C function
+ // `badblocks_show` handles synchronization internally.
+ // `page.as_mut_ptr()` returns a valid pointer to a PAGE_SIZE buffer.
+ // The C function will not write beyond the provided buffer size.
+ unsafe {
+ bindings::badblocks_show(
+ self.blocks.get(),
+ page.as_mut_ptr(),
+ if show_unacknowledged { 1 } else { 0 },
+ )
+ }
+ }
+}
+
+#[pinned_drop]
+impl PinnedDrop for BadBlocks {
+ fn drop(self: Pin<&mut Self>) {
+ // SAFETY: We do not move out of `self` before it is dropped.
+ let this = unsafe { self.get_unchecked_mut() };
+ // SAFETY: By type invariant `this.blocks` is valid. `badblocks_exit` is
+ // safe to call during destruction and will properly clean up allocated
+ // resources.
+ unsafe { bindings::badblocks_exit(this.blocks.get()) };
+ }
+}
+
+// SAFETY: `BadBlocks` can be safely dropped from other threads.
+unsafe impl Send for BadBlocks {}
+
+// SAFETY: All `BadBlocks` methods use internal synchronization.
+unsafe impl Sync for BadBlocks {}
+
+/// Status of a sector range after checking for bad blocks.
+///
+/// This enum represents the result of checking a sector range against the bad blocks
+/// table. It distinguishes between ranges with no bad blocks, ranges with acknowledged
+/// bad blocks, and ranges with unacknowledged bad blocks.
+///
+/// # Examples
+///
+/// ```rust
+/// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
+/// # use kernel::prelude::*;
+/// # use core::ops::{Range, RangeBounds};
+/// # fn perform_io(range: impl RangeBounds<u64>) -> Result<()> { Ok(()) }
+/// # fn remap_and_retry(io_range: impl RangeBounds<u64>, bad_range: Range<u64>)
+/// # -> Result<()> { Ok(()) }
+///
+/// fn handle_io_request(bad_blocks: &BadBlocks, range: impl RangeBounds<u64> + Clone)
+/// -> Result<()>
+/// {
+/// match bad_blocks.check(range.clone()) {
+/// BlockStatus::None => {
+/// // Safe to proceed with I/O - convert range to start/count for legacy function
+/// perform_io(range)
+/// },
+/// BlockStatus::Acknowledged(bad_range) => {
+/// pr_warn!("I/O overlaps acknowledged bad blocks: {:?}", bad_range);
+/// // Attempt remapping or alternative strategy
+/// remap_and_retry(range, bad_range)
+/// },
+/// BlockStatus::Unacknowledged(bad_range) => {
+/// pr_err!("I/O overlaps unacknowledged bad blocks: {:?}", bad_range);
+/// // Treat as serious error
+/// Err(EIO)
+/// },
+/// }
+/// }
+/// # Ok::<(), kernel::error::Error>(())
+/// ```
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum BlockStatus {
+ /// No bad blocks found in the checked range.
+ None,
+ /// The range contains acknowledged bad blocks.
+ ///
+ /// The contained range represents the first bad block
+ /// range encountered.
+ Acknowledged(Range<u64>),
+ /// The range contains unacknowledged bad blocks that need attention.
+ ///
+ /// The contained range represents the boundaries of the first bad block
+ /// range encountered.
+ Unacknowledged(Range<u64>),
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 24/79] block: rust: add `BadBlocks` for bad block tracking
2026-02-15 23:35 ` [PATCH 24/79] block: rust: add `BadBlocks` for bad block tracking Andreas Hindborg
@ 2026-03-16 11:55 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 11:55 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:11AM +0100, Andreas Hindborg wrote:
> Add a safe Rust wrapper around the Linux kernel's badblocks infrastructure
> to track and manage defective sectors on block devices. The BadBlocks type
> provides methods to:
>
> - Mark sectors as bad or good (set_bad/set_good)
> - Check if sector ranges contain bad blocks (check)
> - Automatically handle memory management with PinnedDrop
>
> The implementation includes comprehensive documentation with examples for
> block device drivers that need to avoid known bad sectors to maintain
> data integrity. Bad blocks information is used by device drivers,
> filesystem layers, and device management tools.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> diff --git a/rust/kernel/block/badblocks.rs b/rust/kernel/block/badblocks.rs
> new file mode 100644
> index 0000000000000..a5fe0fde2e755
> --- /dev/null
> +++ b/rust/kernel/block/badblocks.rs
> @@ -0,0 +1,721 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +//! Bad blocks tracking for block devices.
> +//!
> +//! This module provides a safe Rust wrapper around the badblocks
> +//! infrastructure, which is used to track and manage bad sectors on block
> +//! devices. Bad blocks are sectors that cannot reliably store data and should
> +//! be avoided during I/O operations.
Could use a srctree link to badblocks.h here.
> +/// # Examples
> +///
> +/// Basic usage:
> +///
> +/// ```rust
> +/// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
> +/// # use kernel::prelude::*;
> +///
Unhide the imports or remove this empty line.
> +/// // Create a new bad blocks tracker
> +/// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
> +///
> +/// // Mark sectors 100-109 as bad (unacknowledged)
> +/// bad_blocks.set_bad(100..110, false)?;
> +///
> +/// // Check if sector range 95-104 contains bad blocks
> +/// match bad_blocks.check(95..105) {
> +/// BlockStatus::None => pr_info!("No bad blocks found"),
> +/// BlockStatus::Acknowledged(range) => pr_warn!("Acknowledged bad blocks: {:?}", range),
> +/// BlockStatus::Unacknowledged(range) => pr_err!("Unacknowledged bad blocks: {:?}", range),
> +/// }
> +/// # Ok::<(), kernel::error::Error>(())
> +/// ```
> +/// # Invariants
> +///
> +/// - `self.blocks` is a valid `bindings::badblocks` struct.
> +#[pin_data(PinnedDrop)]
> +pub struct BadBlocks {
> + #[pin]
> + blocks: Opaque<bindings::badblocks>,
> +}
> +
> +impl BadBlocks {
> + /// Creates a new bad blocks tracker.
> + ///
> + /// Initializes an empty bad blocks tracker that can manage defective sectors
> + /// on a block device. The tracker starts with no bad blocks recorded and
> + /// allocates a single page for storing bad block entries.
> + ///
> + /// # Returns
> + ///
> + /// Returns a [`PinInit`] that can be used to initialize a [`BadBlocks`] instance.
> + /// Initialization may fail with `ENOMEM` if memory allocation fails.
> + ///
> + /// # Examples
> + ///
> + /// ```rust
> + /// # use kernel::block::badblocks::{BadBlocks, BlockStatus};
> + /// # use kernel::prelude::*;
> + ///
Ditto. (Many times throughout file.)
> + /// // Create and initialize a bad blocks tracker
> + /// let bad_blocks = KBox::pin_init(BadBlocks::new(true), GFP_KERNEL)?;
> + ///
> + /// // The tracker is ready to use with no bad blocks initially
> + /// match bad_blocks.check(0..100) {
> + /// BlockStatus::None => pr_info!("No bad blocks found initially"),
> + /// _ => unreachable!(),
> + /// }
> + /// # Ok::<(), kernel::error::Error>(())
> + /// ```
> + pub fn new(enable: bool) -> impl PinInit<Self, Error> {
> + // INVARIANT: We initialize `self.blocks` below. If initialization fails, an error is
> + // returned.
> + try_pin_init!(Self {
> + blocks <- Opaque::try_ffi_init(|slot| {
> + // SAFETY: `slot` is a valid pointer to uninitialized memory
> + // allocated by the Opaque type. `badblocks_init` is safe to
> + // call with uninitialized memory.
> + to_result(unsafe {bindings::badblocks_init(slot, if enable {1} else {0})})
I think you can just cast the boolean to an integer.
Also, formatting here is off (but ignored by rustfmt due to macro.)
> + /// Enables the bad blocks tracker if it was previously disabled.
> + ///
> + /// Attempts to enable bad block tracking by transitioning the tracker from
> + /// a disabled state to an enabled state.
> + ///
> + /// # Behavior
> + ///
> + /// - If the tracker is disabled, it will be enabled.
> + /// - If the tracker is already enabled, this operation has no effect.
> + /// - The operation is atomic and thread-safe.
> + ///
> + /// # Usage
> + ///
> + /// Bad blocks trackers can be created in a disabled state and enabled later
> + /// when needed. This is useful for conditional bad block tracking or for
> + /// deferring activation until the device is fully initialized.
> + ///
> + /// # Examples
> + ///
> + /// ```rust
> + /// # use kernel::block::badblocks::BadBlocks;
> + /// # use kernel::prelude::*;
> + ///
> + /// // Create a disabled bad blocks tracker
> + /// let bad_blocks = KBox::pin_init(BadBlocks::new(false), GFP_KERNEL)?;
> + /// assert!(!bad_blocks.enabled());
> + ///
> + /// // Enable it when needed
> + /// bad_blocks.enable();
> + /// assert!(bad_blocks.enabled());
> + ///
> + /// // Subsequent enable calls have no effect
> + /// bad_blocks.enable();
> + /// assert!(bad_blocks.enabled());
> + /// # Ok::<(), kernel::error::Error>(())
> + /// ```
> + pub fn enable(&self) {
> + let _ = self.shift_ref().cmpxchg(-1, 0, ordering::Relaxed);
Is there not a C function you can call here? It would be simpler that
way. Surely drivers don't do this directly.
> + }
> +
> + /// Checks whether the bad blocks tracker is currently enabled.
> + ///
> + /// Returns `true` if bad block tracking is active, `false` if it is disabled.
> + /// When disabled, the tracker will not perform bad block checks or operations.
> + ///
> + /// # Returns
> + ///
> + /// - `true` - Bad block tracking is enabled and operational
> + /// - `false` - Bad block tracking is disabled
You explain the meaning of return values twice here. Just drop the
'Returns' section.
> + /// # Thread Safety
> + ///
> + /// This method is thread-safe and uses atomic operations to check the
> + /// tracker's state without requiring external synchronization.
This is implicit from the signature of the function.
> + pub fn set_good(&self, range: impl RangeBounds<u64>) -> Result {
> + let range = Self::range(range);
> + // SAFETY: By type invariant `self.blocks` is valid. The C function
> + // `badblocks_clear` handles synchronization internally.
> + unsafe {
> + bindings::badblocks_clear(self.blocks.get(), range.start, range.end - range.start)
> + }
> + .then_some(())
> + .ok_or(EINVAL)
then_some() is quite obscure. I would recommend if/else here.
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 25/79] block: rust: mq: add Request::end() method for custom status codes
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (23 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 24/79] block: rust: add `BadBlocks` for bad block tracking Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 11:57 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 26/79] block: rnull: add badblocks support Andreas Hindborg
` (53 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add end() method to Request that accepts a custom status code parameter,
refactoring end_ok() to use it with BLK_STS_OK.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 8fe7e126c522a..38289b9f966fa 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -297,13 +297,18 @@ pub(crate) unsafe fn start_unchecked(&mut self) {
/// Notify the block layer that the request has been completed without errors.
pub fn end_ok(self) {
+ self.end(bindings::BLK_STS_OK)
+ }
+
+ /// Notify the block layer that the request has been completed.
+ pub fn end(self, status: u8) {
let request_ptr = self.0.get().cast();
core::mem::forget(self);
// SAFETY: By type invariant, `this.0` was a valid `struct request`. The
// existence of `self` guarantees that there are no `ARef`s pointing to
// this request. Therefore it is safe to hand it back to the block
// layer.
- unsafe { bindings::blk_mq_end_request(request_ptr, bindings::BLK_STS_OK) };
+ unsafe { bindings::blk_mq_end_request(request_ptr, status) };
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 25/79] block: rust: mq: add Request::end() method for custom status codes
2026-02-15 23:35 ` [PATCH 25/79] block: rust: mq: add Request::end() method for custom status codes Andreas Hindborg
@ 2026-03-16 11:57 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 11:57 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:12AM +0100, Andreas Hindborg wrote:
> Add end() method to Request that accepts a custom status code parameter,
> refactoring end_ok() to use it with BLK_STS_OK.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 26/79] block: rnull: add badblocks support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (24 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 25/79] block: rust: mq: add Request::end() method for custom status codes Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 12:02 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 27/79] block: rnull: add badblocks_once support Andreas Hindborg
` (52 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add badblocks support to the rnull driver with a configfs interface for
managing bad sectors.
- Configfs attribute for adding/removing bad blocks via "+start-end" and
"-start-end" syntax.
- Request handling that checks for bad blocks and returns IO errors.
- Updated request completion to handle error status properly.
The badblocks functionality is disabled by default and is enabled when
first bad block is added.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 63 ++++++++++++++++++++++++++++++++++++++---
drivers/block/rnull/rnull.rs | 46 ++++++++++++++++++++++++++----
2 files changed, 100 insertions(+), 9 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 18e32a87673aa..61a76addf468b 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -6,9 +6,12 @@
};
use kernel::{
bindings,
- block::mq::gen_disk::{
- GenDisk,
- GenDiskBuilder, //
+ block::{
+ badblocks::BadBlocks,
+ mq::gen_disk::{
+ GenDisk,
+ GenDiskBuilder, //
+ }, //
},
c_str,
configfs::{
@@ -27,7 +30,10 @@
kstrtobool_bytes,
CString, //
},
- sync::Mutex,
+ sync::{
+ Arc,
+ Mutex, //
+ },
time, //
};
use macros::{
@@ -96,6 +102,7 @@ fn make_group(
home_node: 9,
discard: 10,
no_sched:11,
+ badblocks: 12,
],
};
@@ -118,6 +125,7 @@ fn make_group(
home_node: bindings::NUMA_NO_NODE,
discard: false,
no_sched: false,
+ bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
}),
}),
core::iter::empty(),
@@ -177,6 +185,7 @@ struct DeviceConfigInner {
home_node: i32,
discard: bool,
no_sched: bool,
+ bad_blocks: Arc<BadBlocks>,
}
#[vtable]
@@ -212,6 +221,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
home_node: guard.home_node,
discard: guard.discard,
no_sched: guard.no_sched,
+ bad_blocks: guard.bad_blocks.clone(),
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -367,3 +377,48 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
Ok(())
}
}
+
+#[vtable]
+impl configfs::AttributeOperations<12> for DeviceConfig {
+ type Data = DeviceConfig;
+
+ fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+ let ret = this.data.lock().bad_blocks.show(page, false);
+ if ret < 0 {
+ Err(Error::from_errno(ret as c_int))
+ } else {
+ Ok(ret as usize)
+ }
+ }
+
+ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
+ // This attribute can be set while device is powered.
+
+ for line in core::str::from_utf8(page)?.lines() {
+ let mut chars = line.chars();
+ match chars.next() {
+ Some(sign @ '+' | sign @ '-') => {
+ if let Some((start, end)) = chars.as_str().split_once('-') {
+ let start: u64 = start.parse().map_err(|_| EINVAL)?;
+ let end: u64 = end.parse().map_err(|_| EINVAL)?;
+
+ if start > end {
+ return Err(EINVAL);
+ }
+
+ this.data.lock().bad_blocks.enable();
+
+ if sign == '+' {
+ this.data.lock().bad_blocks.set_bad(start..=end, true)?;
+ } else {
+ this.data.lock().bad_blocks.set_good(start..=end)?;
+ }
+ }
+ }
+ _ => return Err(EINVAL),
+ }
+ }
+
+ Ok(())
+ }
+}
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index b0008e2f9c398..861392c5b5841 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -9,6 +9,7 @@
bindings,
block::{
self,
+ badblocks::{self, BadBlocks},
bio::Segment,
mq::{
self,
@@ -37,6 +38,10 @@
str::CString,
sync::{
aref::ARef,
+ atomic::{
+ ordering,
+ Atomic, //
+ },
Arc,
Mutex, //
},
@@ -155,6 +160,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
home_node: *module_parameters::home_node.value(),
discard: *module_parameters::discard.value() != 0,
no_sched: *module_parameters::no_sched.value() != 0,
+ bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -181,6 +187,7 @@ struct NullBlkOptions<'a> {
home_node: i32,
discard: bool,
no_sched: bool,
+ bad_blocks: Arc<BadBlocks>,
}
struct NullBlkDevice;
@@ -198,6 +205,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
home_node,
discard,
no_sched,
+ bad_blocks,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -226,6 +234,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
completion_time,
memory_backed,
block_size: block_size.into(),
+ bad_blocks,
}),
GFP_KERNEL,
)?;
@@ -327,6 +336,16 @@ fn transfer(
}
Ok(())
}
+
+ fn end_request(rq: Owned<mq::Request<Self>>) {
+ let status = rq.data_ref().error.load(ordering::Relaxed);
+ rq.data_ref().error.store(0, ordering::Relaxed);
+
+ match status {
+ 0 => rq.end_ok(),
+ _ => rq.end(bindings::BLK_STS_IOERR),
+ }
+ }
}
const _CHEKC_STATUS_WIDTH: () = build_assert!((PAGE_SIZE >> SECTOR_SHIFT) <= 64);
@@ -373,12 +392,14 @@ struct QueueData {
completion_time: Delta,
memory_backed: bool,
block_size: u64,
+ bad_blocks: Arc<BadBlocks>,
}
#[pin_data]
struct Pdu {
#[pin]
timer: kernel::time::hrtimer::HrTimer<Self>,
+ error: Atomic<u32>,
}
impl HrTimerCallback for Pdu {
@@ -408,6 +429,7 @@ impl Operations for NullBlkDevice {
fn new_request_data() -> impl PinInit<Self::RequestData> {
pin_init!(Pdu {
timer <- kernel::time::hrtimer::HrTimer::new(),
+ error: Atomic::new(0),
})
}
@@ -417,6 +439,19 @@ fn queue_rq(
mut rq: Owned<mq::Request<Self>>,
_is_last: bool,
) -> Result {
+ if queue_data.bad_blocks.enabled() {
+ let start = rq.sector();
+ let end = start + u64::from(rq.sectors());
+ if !matches!(
+ queue_data.bad_blocks.check(start..end),
+ badblocks::BlockStatus::None
+ ) {
+ rq.data_ref().error.store(1, ordering::Relaxed);
+ }
+ }
+
+ // TODO: Skip IO if bad block.
+
if queue_data.memory_backed {
let tree = &queue_data.tree;
let command = rq.command();
@@ -437,7 +472,7 @@ fn queue_rq(
}
match queue_data.irq_mode {
- IRQMode::None => rq.end_ok(),
+ IRQMode::None => Self::end_request(rq),
IRQMode::Soft => mq::Request::complete(rq.into()),
IRQMode::Timer => {
OwnableRefCounted::into_shared(rq)
@@ -451,9 +486,10 @@ fn queue_rq(
fn commit_rqs(_queue_data: Pin<&QueueData>) {}
fn complete(rq: ARef<mq::Request<Self>>) {
- OwnableRefCounted::try_from_shared(rq)
- .map_err(|_e| kernel::error::code::EIO)
- .expect("Failed to complete request")
- .end_ok();
+ Self::end_request(
+ OwnableRefCounted::try_from_shared(rq)
+ .map_err(|_e| kernel::error::code::EIO)
+ .expect("Failed to complete request"),
+ )
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 26/79] block: rnull: add badblocks support
2026-02-15 23:35 ` [PATCH 26/79] block: rnull: add badblocks support Andreas Hindborg
@ 2026-03-16 12:02 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 12:02 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:13AM +0100, Andreas Hindborg wrote:
> Add badblocks support to the rnull driver with a configfs interface for
> managing bad sectors.
>
> - Configfs attribute for adding/removing bad blocks via "+start-end" and
> "-start-end" syntax.
> - Request handling that checks for bad blocks and returns IO errors.
> - Updated request completion to handle error status properly.
>
> The badblocks functionality is disabled by default and is enabled when
> first bad block is added.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> + fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> + // This attribute can be set while device is powered.
> +
> + for line in core::str::from_utf8(page)?.lines() {
> + let mut chars = line.chars();
> + match chars.next() {
> + Some(sign @ '+' | sign @ '-') => {
> + if let Some((start, end)) = chars.as_str().split_once('-') {
> + let start: u64 = start.parse().map_err(|_| EINVAL)?;
> + let end: u64 = end.parse().map_err(|_| EINVAL)?;
> +
> + if start > end {
> + return Err(EINVAL);
> + }
> +
> + this.data.lock().bad_blocks.enable();
> +
> + if sign == '+' {
> + this.data.lock().bad_blocks.set_bad(start..=end, true)?;
> + } else {
> + this.data.lock().bad_blocks.set_good(start..=end)?;
Taking lock twice: TOCTOU.
> @@ -118,6 +125,7 @@ fn make_group(
> home_node: bindings::NUMA_NO_NODE,
> discard: false,
> no_sched: false,
> + bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
> }),
> }),
> core::iter::empty(),
[..]
> @@ -155,6 +160,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
> home_node: *module_parameters::home_node.value(),
> discard: *module_parameters::discard.value() != 0,
> no_sched: *module_parameters::no_sched.value() != 0,
> + bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
It seems weird to construct this Arc in two places. Is it shared or not?
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 27/79] block: rnull: add badblocks_once support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (25 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 26/79] block: rnull: add badblocks support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 28/79] block: rnull: add partial I/O support for bad blocks Andreas Hindborg
` (51 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for the badblocks_once feature, which automatically clears
bad blocks after they are encountered during I/O operations. This
matches the functionality in the C null_blk driver.
When badblocks_once is enabled:
- Bad blocks are checked during I/O requests as usual
- If a bad block is encountered, the I/O is marked as failed
- The bad block range is immediately cleared from the bad blocks table
- Subsequent I/O to the same sectors will succeed
This feature is useful for testing scenarios where bad blocks are
transient or where devices can recover from bad sectors after a single
access attempt.
The feature is configurable via the configfs badblocks_once attribute
and disabled by default, maintaining compatibility with existing
behavior.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 31 +++++++++++++++++++++++++++++++
drivers/block/rnull/rnull.rs | 21 +++++++++++++++------
2 files changed, 46 insertions(+), 6 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 61a76addf468b..a39691b39e374 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -103,6 +103,7 @@ fn make_group(
discard: 10,
no_sched:11,
badblocks: 12,
+ badblocks_once: 13,
],
};
@@ -126,6 +127,7 @@ fn make_group(
discard: false,
no_sched: false,
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
+ bad_blocks_once: false,
}),
}),
core::iter::empty(),
@@ -186,6 +188,7 @@ struct DeviceConfigInner {
discard: bool,
no_sched: bool,
bad_blocks: Arc<BadBlocks>,
+ bad_blocks_once: bool,
}
#[vtable]
@@ -222,6 +225,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
discard: guard.discard,
no_sched: guard.no_sched,
bad_blocks: guard.bad_blocks.clone(),
+ bad_blocks_once: guard.bad_blocks_once,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -422,3 +426,30 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
Ok(())
}
}
+
+#[vtable]
+impl configfs::AttributeOperations<13> for DeviceConfig {
+ type Data = DeviceConfig;
+
+ fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
+ let mut writer = kernel::str::Formatter::new(page);
+
+ if this.data.lock().bad_blocks_once {
+ writer.write_str("1\n")?;
+ } else {
+ writer.write_str("0\n")?;
+ }
+
+ Ok(writer.bytes_written())
+ }
+
+ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
+ if this.data.lock().powered {
+ return Err(EBUSY);
+ }
+
+ this.data.lock().bad_blocks_once = kstrtobool_bytes(page)?;
+
+ Ok(())
+ }
+}
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 861392c5b5841..0f569c5b65f77 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -161,6 +161,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
discard: *module_parameters::discard.value() != 0,
no_sched: *module_parameters::no_sched.value() != 0,
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
+ bad_blocks_once: false,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -188,6 +189,7 @@ struct NullBlkOptions<'a> {
discard: bool,
no_sched: bool,
bad_blocks: Arc<BadBlocks>,
+ bad_blocks_once: bool,
}
struct NullBlkDevice;
@@ -206,6 +208,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
discard,
no_sched,
bad_blocks,
+ bad_blocks_once,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -235,6 +238,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
memory_backed,
block_size: block_size.into(),
bad_blocks,
+ bad_blocks_once,
}),
GFP_KERNEL,
)?;
@@ -393,6 +397,7 @@ struct QueueData {
memory_backed: bool,
block_size: u64,
bad_blocks: Arc<BadBlocks>,
+ bad_blocks_once: bool,
}
#[pin_data]
@@ -442,12 +447,16 @@ fn queue_rq(
if queue_data.bad_blocks.enabled() {
let start = rq.sector();
let end = start + u64::from(rq.sectors());
- if !matches!(
- queue_data.bad_blocks.check(start..end),
- badblocks::BlockStatus::None
- ) {
- rq.data_ref().error.store(1, ordering::Relaxed);
- }
+ match queue_data.bad_blocks.check(start..end) {
+ badblocks::BlockStatus::None => {}
+ badblocks::BlockStatus::Acknowledged(range)
+ | badblocks::BlockStatus::Unacknowledged(range) => {
+ rq.data_ref().error.store(1, ordering::Relaxed);
+ if queue_data.bad_blocks_once {
+ queue_data.bad_blocks.set_good(range)?;
+ }
+ }
+ };
}
// TODO: Skip IO if bad block.
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 28/79] block: rnull: add partial I/O support for bad blocks
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (26 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 27/79] block: rnull: add badblocks_once support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-03-16 12:14 ` Alice Ryhl
2026-02-15 23:35 ` [PATCH 29/79] block: rust: add `TagSet` private data support Andreas Hindborg
` (50 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add bad_blocks_partial_io configuration option that allows partial I/O
completion when encountering bad blocks, rather than failing the entire
request.
When enabled, requests are truncated to stop before the first bad block
range, allowing the valid portion to be processed successfully. This
improves compatibility with applications that can handle partial
reads/writes.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 32 ++--------
drivers/block/rnull/rnull.rs | 125 ++++++++++++++++++++++++++++------------
2 files changed, 95 insertions(+), 62 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index a39691b39e374..c08a3cbd66f18 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -104,6 +104,7 @@ fn make_group(
no_sched:11,
badblocks: 12,
badblocks_once: 13,
+ badblocks_partial_io: 14,
],
};
@@ -128,6 +129,7 @@ fn make_group(
no_sched: false,
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
bad_blocks_once: false,
+ bad_blocks_partial_io: false,
}),
}),
core::iter::empty(),
@@ -189,6 +191,7 @@ struct DeviceConfigInner {
no_sched: bool,
bad_blocks: Arc<BadBlocks>,
bad_blocks_once: bool,
+ bad_blocks_partial_io: bool,
}
#[vtable]
@@ -226,6 +229,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
no_sched: guard.no_sched,
bad_blocks: guard.bad_blocks.clone(),
bad_blocks_once: guard.bad_blocks_once,
+ bad_blocks_partial_io: guard.bad_blocks_partial_io,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -427,29 +431,5 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
-#[vtable]
-impl configfs::AttributeOperations<13> for DeviceConfig {
- type Data = DeviceConfig;
-
- fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
- let mut writer = kernel::str::Formatter::new(page);
-
- if this.data.lock().bad_blocks_once {
- writer.write_str("1\n")?;
- } else {
- writer.write_str("0\n")?;
- }
-
- Ok(writer.bytes_written())
- }
-
- fn store(this: &DeviceConfig, page: &[u8]) -> Result {
- if this.data.lock().powered {
- return Err(EBUSY);
- }
-
- this.data.lock().bad_blocks_once = kstrtobool_bytes(page)?;
-
- Ok(())
- }
-}
+configfs_simple_bool_field!(DeviceConfig, 13, bad_blocks_once);
+configfs_simple_bool_field!(DeviceConfig, 14, bad_blocks_partial_io);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 0f569c5b65f77..6691e5912c5c9 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -162,6 +162,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
no_sched: *module_parameters::no_sched.value() != 0,
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
bad_blocks_once: false,
+ bad_blocks_partial_io: false,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -190,6 +191,7 @@ struct NullBlkOptions<'a> {
no_sched: bool,
bad_blocks: Arc<BadBlocks>,
bad_blocks_once: bool,
+ bad_blocks_partial_io: bool,
}
struct NullBlkDevice;
@@ -209,6 +211,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
no_sched,
bad_blocks,
bad_blocks_once,
+ bad_blocks_partial_io,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -239,6 +242,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
block_size: block_size.into(),
bad_blocks,
bad_blocks_once,
+ bad_blocks_partial_io,
}),
GFP_KERNEL,
)?;
@@ -327,16 +331,62 @@ fn discard(tree: &Tree, mut sector: u64, sectors: u64, block_size: u64) -> Resul
}
#[inline(never)]
- fn transfer(
- command: bindings::req_op,
- tree: &Tree,
- sector: u64,
- segment: Segment<'_>,
+ fn transfer(rq: &mut Owned<mq::Request<Self>>, tree: &Tree, sectors: u32) -> Result {
+ let mut sector = rq.sector();
+ let end_sector = sector + <u32 as Into<u64>>::into(sectors);
+ let command = rq.command();
+
+ for bio in rq.bio_iter_mut() {
+ let segment_iter = bio.segment_iter();
+ for segment in segment_iter {
+ // Length might be limited by bad blocks.
+ let length = segment
+ .len()
+ .min((sector - end_sector) as u32 >> SECTOR_SHIFT);
+ match command {
+ bindings::req_op_REQ_OP_WRITE => Self::write(tree, sector, segment)?,
+ bindings::req_op_REQ_OP_READ => Self::read(tree, sector, segment)?,
+ _ => (),
+ }
+ sector += u64::from(length) >> SECTOR_SHIFT;
+
+ if sector >= end_sector {
+ return Ok(());
+ }
+ }
+ }
+ Ok(())
+ }
+
+ fn handle_bad_blocks(
+ rq: &mut Owned<mq::Request<Self>>,
+ queue_data: &QueueData,
+ sectors: &mut u32,
) -> Result {
- match command {
- bindings::req_op_REQ_OP_WRITE => Self::write(tree, sector, segment)?,
- bindings::req_op_REQ_OP_READ => Self::read(tree, sector, segment)?,
- _ => (),
+ if queue_data.bad_blocks.enabled() {
+ let start = rq.sector();
+ let end = start + u64::from(*sectors);
+ match queue_data.bad_blocks.check(start..end) {
+ badblocks::BlockStatus::None => {}
+ badblocks::BlockStatus::Acknowledged(mut range)
+ | badblocks::BlockStatus::Unacknowledged(mut range) => {
+ rq.data_ref().error.store(1, ordering::Relaxed);
+
+ if queue_data.bad_blocks_once {
+ queue_data.bad_blocks.set_good(range.clone())?;
+ }
+
+ if queue_data.bad_blocks_partial_io {
+ let block_size_sectors = queue_data.block_size >> SECTOR_SHIFT;
+ range.start = align_down(range.start, block_size_sectors);
+ if start < range.start {
+ *sectors = (range.start - start) as u32;
+ }
+ } else {
+ *sectors = 0;
+ }
+ }
+ };
}
Ok(())
}
@@ -398,6 +448,7 @@ struct QueueData {
block_size: u64,
bad_blocks: Arc<BadBlocks>,
bad_blocks_once: bool,
+ bad_blocks_partial_io: bool,
}
#[pin_data]
@@ -426,6 +477,30 @@ impl HasHrTimer<Self> for Pdu {
}
}
+fn is_power_of_two<T>(value: T) -> bool
+where
+ T: core::ops::Sub<T, Output = T>,
+ T: core::ops::BitAnd<Output = T>,
+ T: core::cmp::PartialOrd<T>,
+ T: Copy,
+ T: From<u8>,
+{
+ (value > 0u8.into()) && (value & (value - 1u8.into())) == 0u8.into()
+}
+
+fn align_down<T>(value: T, to: T) -> T
+where
+ T: core::ops::Sub<T, Output = T>,
+ T: core::ops::Not<Output = T>,
+ T: core::ops::BitAnd<Output = T>,
+ T: core::cmp::PartialOrd<T>,
+ T: Copy,
+ T: From<u8>,
+{
+ debug_assert!(is_power_of_two(to));
+ value & !(to - 1u8.into())
+}
+
#[vtable]
impl Operations for NullBlkDevice {
type QueueData = Pin<KBox<QueueData>>;
@@ -444,39 +519,17 @@ fn queue_rq(
mut rq: Owned<mq::Request<Self>>,
_is_last: bool,
) -> Result {
- if queue_data.bad_blocks.enabled() {
- let start = rq.sector();
- let end = start + u64::from(rq.sectors());
- match queue_data.bad_blocks.check(start..end) {
- badblocks::BlockStatus::None => {}
- badblocks::BlockStatus::Acknowledged(range)
- | badblocks::BlockStatus::Unacknowledged(range) => {
- rq.data_ref().error.store(1, ordering::Relaxed);
- if queue_data.bad_blocks_once {
- queue_data.bad_blocks.set_good(range)?;
- }
- }
- };
- }
+ let mut sectors = rq.sectors();
- // TODO: Skip IO if bad block.
+ Self::handle_bad_blocks(&mut rq, queue_data.get_ref(), &mut sectors)?;
if queue_data.memory_backed {
let tree = &queue_data.tree;
- let command = rq.command();
- let mut sector = rq.sector();
- if command == bindings::req_op_REQ_OP_DISCARD {
- Self::discard(tree, sector, rq.sectors().into(), queue_data.block_size)?;
+ if rq.command() == bindings::req_op_REQ_OP_DISCARD {
+ Self::discard(tree, rq.sector(), sectors.into(), queue_data.block_size)?;
} else {
- for bio in rq.bio_iter_mut() {
- let segment_iter = bio.segment_iter();
- for segment in segment_iter {
- let length = segment.len();
- Self::transfer(command, tree, sector, segment)?;
- sector += u64::from(length) >> block::SECTOR_SHIFT;
- }
- }
+ Self::transfer(&mut rq, tree, sectors)?;
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* Re: [PATCH 28/79] block: rnull: add partial I/O support for bad blocks
2026-02-15 23:35 ` [PATCH 28/79] block: rnull: add partial I/O support for bad blocks Andreas Hindborg
@ 2026-03-16 12:14 ` Alice Ryhl
0 siblings, 0 replies; 114+ messages in thread
From: Alice Ryhl @ 2026-03-16 12:14 UTC (permalink / raw)
To: Andreas Hindborg
Cc: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett, linux-block,
rust-for-linux, linux-kernel, linux-mm
On Mon, Feb 16, 2026 at 12:35:15AM +0100, Andreas Hindborg wrote:
> Add bad_blocks_partial_io configuration option that allows partial I/O
> completion when encountering bad blocks, rather than failing the entire
> request.
>
> When enabled, requests are truncated to stop before the first bad block
> range, allowing the valid portion to be processed successfully. This
> improves compatibility with applications that can handle partial
> reads/writes.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> -#[vtable]
> -impl configfs::AttributeOperations<13> for DeviceConfig {
> - type Data = DeviceConfig;
> -
> - fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
> - let mut writer = kernel::str::Formatter::new(page);
> -
> - if this.data.lock().bad_blocks_once {
> - writer.write_str("1\n")?;
> - } else {
> - writer.write_str("0\n")?;
> - }
> -
> - Ok(writer.bytes_written())
> - }
> -
> - fn store(this: &DeviceConfig, page: &[u8]) -> Result {
> - if this.data.lock().powered {
> - return Err(EBUSY);
> - }
> -
> - this.data.lock().bad_blocks_once = kstrtobool_bytes(page)?;
> -
> - Ok(())
> - }
> -}
> +configfs_simple_bool_field!(DeviceConfig, 13, bad_blocks_once);
Squash this into previous patch.
> +fn is_power_of_two<T>(value: T) -> bool
> +where
> + T: core::ops::Sub<T, Output = T>,
> + T: core::ops::BitAnd<Output = T>,
> + T: core::cmp::PartialOrd<T>,
> + T: Copy,
> + T: From<u8>,
> +{
> + (value > 0u8.into()) && (value & (value - 1u8.into())) == 0u8.into()
> +}
This is in the standard library.
> +fn align_down<T>(value: T, to: T) -> T
> +where
> + T: core::ops::Sub<T, Output = T>,
> + T: core::ops::Not<Output = T>,
> + T: core::ops::BitAnd<Output = T>,
> + T: core::cmp::PartialOrd<T>,
> + T: Copy,
> + T: From<u8>,
> +{
> + debug_assert!(is_power_of_two(to));
> + value & !(to - 1u8.into())
> +}
Overlap with:
https://lore.kernel.org/rust-for-linux/20260221020952.412352-22-jhubbard@nvidia.com/
Alice
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 29/79] block: rust: add `TagSet` private data support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (27 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 28/79] block: rnull: add partial I/O support for bad blocks Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 30/79] block: rust: add `hctx` " Andreas Hindborg
` (49 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
C block device drivers can attach private data to a `struct
blk_mq_tag_set`. Add support for this feature for Rust block device
drivers via the `Operations::TagSetData` associated type.
The private data is passed to `TagSet::new` and is stored in the
`driver_data` field of the underlying `struct blk_mq_tag_set`. It is
released when the `TagSet` is dropped.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 3 ++-
rust/kernel/block/mq.rs | 6 ++++--
rust/kernel/block/mq/operations.rs | 4 ++++
rust/kernel/block/mq/tag_set.rs | 25 ++++++++++++++++++++-----
4 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 6691e5912c5c9..9e8d085924040 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -229,7 +229,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
}
let tagset = Arc::pin_init(
- TagSet::new(submit_queues, 256, 1, home_node, flags),
+ TagSet::new(submit_queues, (), 256, 1, home_node, flags),
GFP_KERNEL,
)?;
@@ -505,6 +505,7 @@ fn align_down<T>(value: T, to: T) -> T
impl Operations for NullBlkDevice {
type QueueData = Pin<KBox<QueueData>>;
type RequestData = Pdu;
+ type TagSetData = ();
fn new_request_data() -> impl PinInit<Self::RequestData> {
pin_init!(Pdu {
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index d3957f2fb1a66..415be31e9a777 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -71,6 +71,7 @@
//! impl Operations for MyBlkDevice {
//! type RequestData = ();
//! type QueueData = ();
+//! type TagSetData = ();
//!
//! fn new_request_data(
//! ) -> impl PinInit<()> {
@@ -94,8 +95,9 @@
//!
//! let tagset: Arc<TagSet<MyBlkDevice>> =
//! Arc::pin_init(
-//! TagSet::new(1, 256, 1, bindings::NUMA_NO_NODE, mq::tag_set::Flags::default()),
-//! GFP_KERNEL)?;
+//! TagSet::new(1, (), 256, 1, bindings::NUMA_NO_NODE, mq::tag_set::Flags::default()),
+//! GFP_KERNEL
+//! )?;
//! let mut disk = gen_disk::GenDiskBuilder::new()
//! .capacity_sectors(4096)
//! .build(fmt!("myblk"), tagset, ())?;
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index cd37b939bbf30..9aab6240428cc 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -44,6 +44,10 @@ pub trait Operations: Sized {
/// the `GenDisk` associated with this `Operations` implementation.
type QueueData: ForeignOwnable;
+ /// Data associated with a `TagSet`. This is stored as a pointer in `struct
+ /// blk_mq_tag_set`.
+ type TagSetData: ForeignOwnable;
+
/// Called by the kernel to get an initializer for a `Pin<&mut RequestData>`.
fn new_request_data() -> impl PinInit<Self::RequestData>;
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index e9b36d6329b9b..f18b51e5217fe 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -10,8 +10,8 @@
bindings,
block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations},
error::{self, Result},
- prelude::try_pin_init,
- types::Opaque,
+ try_pin_init,
+ types::{ForeignOwnable, Opaque},
};
use core::{convert::TryInto, marker::PhantomData};
use pin_init::{pin_data, pinned_drop, PinInit};
@@ -39,6 +39,7 @@ impl<T: Operations> TagSet<T> {
/// Try to create a new tag set
pub fn new(
nr_hw_queues: u32,
+ tagset_data: T::TagSetData,
num_tags: u32,
num_maps: u32,
numa_node: i32,
@@ -58,7 +59,7 @@ pub fn new(
queue_depth: num_tags,
cmd_size,
flags: flags.into_inner(),
- driver_data: core::ptr::null_mut::<crate::ffi::c_void>(),
+ driver_data: tagset_data.into_foreign(),
nr_maps: num_maps,
..tag_set
}
@@ -71,7 +72,14 @@ pub fn new(
// SAFETY: we do not move out of `tag_set`.
let tag_set: &mut Opaque<_> = unsafe { Pin::get_unchecked_mut(tag_set) };
// SAFETY: `tag_set` is a reference to an initialized `blk_mq_tag_set`.
- error::to_result( unsafe { bindings::blk_mq_alloc_tag_set(tag_set.get())})
+ let status = error::to_result(
+ unsafe { bindings::blk_mq_alloc_tag_set(tag_set.get())}
+ );
+ if status.is_err() {
+ // SAFETY: We created `driver_data` above with `into_foreign`
+ unsafe { T::TagSetData::from_foreign((*tag_set.get()).driver_data) };
+ }
+ status
}),
_p: PhantomData,
})
@@ -87,7 +95,14 @@ pub(crate) fn raw_tag_set(&self) -> *mut bindings::blk_mq_tag_set {
impl<T: Operations> PinnedDrop for TagSet<T> {
fn drop(self: Pin<&mut Self>) {
// SAFETY: By type invariant `inner` is valid and has been properly
- // initialized during construction.
+ // initialised during construction.
+ let tagset_data = unsafe { (*self.inner.get()).driver_data };
+
+ // SAFETY: `inner` is valid and has been properly initialised during construction.
unsafe { bindings::blk_mq_free_tag_set(self.inner.get()) };
+
+ // SAFETY: `tagset_data` was created by a call to
+ // `ForeignOwnable::into_foreign` in `TagSet::try_new()`
+ unsafe { T::TagSetData::from_foreign(tagset_data) };
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 30/79] block: rust: add `hctx` private data support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (28 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 29/79] block: rust: add `TagSet` private data support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 31/79] block: rnull: add volatile cache emulation Andreas Hindborg
` (48 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
C block device drivers can attach private data to a hardware context
(`struct blk_mq_hw_ctx`). Add support for this feature for Rust block
device drivers via the `Operations::HwData` associated type.
The private data is created in the `init_hctx` callback and stored in
the `driver_data` field of `blk_mq_hw_ctx`. It is passed to `queue_rq`,
`commit_rqs`, and `poll` callbacks, and is released in `exit_hctx`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 8 +++-
rust/kernel/block/mq.rs | 23 ++++++++++-
rust/kernel/block/mq/operations.rs | 85 +++++++++++++++++++++++++++++++-------
3 files changed, 97 insertions(+), 19 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 9e8d085924040..4e226186d2f36 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -506,6 +506,7 @@ impl Operations for NullBlkDevice {
type QueueData = Pin<KBox<QueueData>>;
type RequestData = Pdu;
type TagSetData = ();
+ type HwData = ();
fn new_request_data() -> impl PinInit<Self::RequestData> {
pin_init!(Pdu {
@@ -516,6 +517,7 @@ fn new_request_data() -> impl PinInit<Self::RequestData> {
#[inline(always)]
fn queue_rq(
+ _hw_data: (),
queue_data: Pin<&QueueData>,
mut rq: Owned<mq::Request<Self>>,
_is_last: bool,
@@ -546,7 +548,11 @@ fn queue_rq(
Ok(())
}
- fn commit_rqs(_queue_data: Pin<&QueueData>) {}
+ fn commit_rqs(_hw_data: (), _queue_data: Pin<&QueueData>) {}
+
+ fn init_hctx(_tagset_data: (), _hctx_idx: u32) -> Result {
+ Ok(())
+ }
fn complete(rq: ARef<mq::Request<Self>>) {
Self::end_request(
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 415be31e9a777..3eab3ca8f5480 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -17,6 +17,12 @@
//! - The [`GenDisk`] type that abstracts the C type `struct gendisk`.
//! - The [`Request`] type that abstracts the C type `struct request`.
//!
+//! Many of the C types that this module abstracts allow a driver to carry
+//! private data, either embedded in the struct directly, or as a C `void*`. In
+//! these abstractions, this data is typed. The types of the data is defined by
+//! associated types in `Operations`, see [`Operations::RequestData`] for an
+//! example.
+//!
//! The kernel will interface with the block device driver by calling the method
//! implementations of the `Operations` trait.
//!
@@ -71,6 +77,7 @@
//! impl Operations for MyBlkDevice {
//! type RequestData = ();
//! type QueueData = ();
+//! type HwData = ();
//! type TagSetData = ();
//!
//! fn new_request_data(
@@ -78,12 +85,17 @@
//! pin_init::zeroed::<()>()
//! }
//!
-//! fn queue_rq(_queue_data: (), rq: Owned<Request<Self>>, _is_last: bool) -> Result {
+//! fn queue_rq(
+//! _hw_data: (),
+//! _queue_data: (),
+//! rq: Owned<Request<Self>>,
+//! _is_last: bool
+//! ) -> Result {
//! rq.end_ok();
//! Ok(())
//! }
//!
-//! fn commit_rqs(_queue_data: ()) {}
+//! fn commit_rqs(_hw_data: (), _queue_data: ()) {}
//!
//! fn complete(rq: ARef<Request<Self>>) {
//! OwnableRefCounted::try_from_shared(rq)
@@ -91,6 +103,13 @@
//! .expect("Fatal error - expected to be able to end request")
//! .end_ok();
//! }
+//!
+//! fn init_hctx(
+//! _tagset_data: (),
+//! _hctx_idx: u32,
+//! ) -> Result<Self::HwData> {
+//! Ok(())
+//! }
//! }
//!
//! let tagset: Arc<TagSet<MyBlkDevice>> =
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 9aab6240428cc..6641c340d87f4 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -44,6 +44,10 @@ pub trait Operations: Sized {
/// the `GenDisk` associated with this `Operations` implementation.
type QueueData: ForeignOwnable;
+ /// Data associated with a dispatch queue. This is stored as a pointer in
+ /// the C `struct blk_mq_hw_ctx` that represents a hardware queue.
+ type HwData: ForeignOwnable;
+
/// Data associated with a `TagSet`. This is stored as a pointer in `struct
/// blk_mq_tag_set`.
type TagSetData: ForeignOwnable;
@@ -54,20 +58,30 @@ pub trait Operations: Sized {
/// Called by the kernel to queue a request with the driver. If `is_last` is
/// `false`, the driver is allowed to defer committing the request.
fn queue_rq(
+ hw_data: ForeignBorrowed<'_, Self::HwData>,
queue_data: ForeignBorrowed<'_, Self::QueueData>,
rq: Owned<Request<Self>>,
is_last: bool,
) -> Result;
/// Called by the kernel to indicate that queued requests should be submitted.
- fn commit_rqs(queue_data: ForeignBorrowed<'_, Self::QueueData>);
+ fn commit_rqs(
+ hw_data: ForeignBorrowed<'_, Self::HwData>,
+ queue_data: ForeignBorrowed<'_, Self::QueueData>,
+ );
+
+ /// Called by the kernel to allocate and initialize a driver specific hardware context data.
+ fn init_hctx(
+ tagset_data: ForeignBorrowed<'_, Self::TagSetData>,
+ hctx_idx: u32,
+ ) -> Result<Self::HwData>;
/// Called by the kernel when the request is completed.
fn complete(rq: ARef<Request<Self>>);
/// Called by the kernel to poll the device for completed requests. Only
/// used for poll queues.
- fn poll() -> bool {
+ fn poll(_hw_data: ForeignBorrowed<'_, Self::HwData>) -> bool {
build_error!(crate::error::VTABLE_DEFAULT_ERROR)
}
}
@@ -127,6 +141,11 @@ impl<T: Operations> OperationsVTable<T> {
let mut rq =
unsafe { Owned::from_raw(NonNull::<Request<T>>::new_unchecked((*bd).rq.cast())) };
+ // SAFETY: The safety requirement for this function ensure that `hctx`
+ // is valid and that `driver_data` was produced by a call to
+ // `into_foreign` in `Self::init_hctx_callback`.
+ let hw_data = unsafe { T::HwData::borrow((*hctx).driver_data) };
+
// SAFETY: `hctx` is valid as required by this function.
let queue_data = unsafe { (*(*hctx).queue).queuedata };
@@ -140,6 +159,7 @@ impl<T: Operations> OperationsVTable<T> {
unsafe { rq.start_unchecked() };
let ret = T::queue_rq(
+ hw_data,
queue_data,
rq,
// SAFETY: `bd` is valid as required by the safety requirement for
@@ -162,6 +182,10 @@ impl<T: Operations> OperationsVTable<T> {
/// This function may only be called by blk-mq C infrastructure. The caller
/// must ensure that `hctx` is valid.
unsafe extern "C" fn commit_rqs_callback(hctx: *mut bindings::blk_mq_hw_ctx) {
+ // SAFETY: `driver_data` was installed by us in `init_hctx_callback` as
+ // the result of a call to `into_foreign`.
+ let hw_data = unsafe { T::HwData::borrow((*hctx).driver_data) };
+
// SAFETY: `hctx` is valid as required by this function.
let queue_data = unsafe { (*(*hctx).queue).queuedata };
@@ -170,7 +194,7 @@ impl<T: Operations> OperationsVTable<T> {
// `ForeignOwnable::from_foreign()` is only called when the tagset is
// dropped, which happens after we are dropped.
let queue_data = unsafe { T::QueueData::borrow(queue_data) };
- T::commit_rqs(queue_data)
+ T::commit_rqs(hw_data, queue_data)
}
/// This function is called by the C kernel. A pointer to this function is
@@ -194,12 +218,18 @@ impl<T: Operations> OperationsVTable<T> {
///
/// # Safety
///
- /// This function may only be called by blk-mq C infrastructure.
+ /// This function may only be called by blk-mq C infrastructure. `hctx` must
+ /// be a pointer to a valid and aligned `struct blk_mq_hw_ctx` that was
+ /// previously initialized by a call to `init_hctx_callback`.
unsafe extern "C" fn poll_callback(
- _hctx: *mut bindings::blk_mq_hw_ctx,
+ hctx: *mut bindings::blk_mq_hw_ctx,
_iob: *mut bindings::io_comp_batch,
) -> crate::ffi::c_int {
- T::poll().into()
+ // SAFETY: By function safety requirement, `hctx` was initialized by
+ // `init_hctx_callback` and thus `driver_data` came from a call to
+ // `into_foreign`.
+ let hw_data = unsafe { T::HwData::borrow((*hctx).driver_data) };
+ T::poll(hw_data).into()
}
/// This function is called by the C kernel. A pointer to this function is
@@ -207,15 +237,29 @@ impl<T: Operations> OperationsVTable<T> {
///
/// # Safety
///
- /// This function may only be called by blk-mq C infrastructure. This
- /// function may only be called once before `exit_hctx_callback` is called
- /// for the same context.
+ /// This function may only be called by blk-mq C infrastructure.
+ /// `tagset_data` must be initialized by the initializer returned by
+ /// `TagSet::try_new` as part of tag set initialization. `hctx` must be a
+ /// pointer to a valid `blk_mq_hw_ctx` where the `driver_data` field was not
+ /// yet initialized. This function may only be called onece before
+ /// `exit_hctx_callback` is called for the same context.
unsafe extern "C" fn init_hctx_callback(
- _hctx: *mut bindings::blk_mq_hw_ctx,
- _tagset_data: *mut crate::ffi::c_void,
- _hctx_idx: crate::ffi::c_uint,
- ) -> crate::ffi::c_int {
- from_result(|| Ok(0))
+ hctx: *mut bindings::blk_mq_hw_ctx,
+ tagset_data: *mut core::ffi::c_void,
+ hctx_idx: crate::ffi::c_uint,
+ ) -> core::ffi::c_int {
+ from_result(|| {
+ // SAFETY: By the safety requirements of this function,
+ // `tagset_data` came from a call to `into_foreign` when the
+ // `TagSet` was initialized.
+ let tagset_data = unsafe { T::TagSetData::borrow(tagset_data) };
+ let data = T::init_hctx(tagset_data, hctx_idx)?;
+
+ // SAFETY: by the safety requirments of this function, `hctx` is
+ // valid for write
+ unsafe { (*hctx).driver_data = data.into_foreign().cast() };
+ Ok(0)
+ })
}
/// This function is called by the C kernel. A pointer to this function is
@@ -223,11 +267,20 @@ impl<T: Operations> OperationsVTable<T> {
///
/// # Safety
///
- /// This function may only be called by blk-mq C infrastructure.
+ /// This function may only be called by blk-mq C infrastructure. `hctx` must
+ /// be a valid pointer that was previously initialized by a call to
+ /// `init_hctx_callback`. This function may be called only once after
+ /// `init_hctx_callback` was called.
unsafe extern "C" fn exit_hctx_callback(
- _hctx: *mut bindings::blk_mq_hw_ctx,
+ hctx: *mut bindings::blk_mq_hw_ctx,
_hctx_idx: crate::ffi::c_uint,
) {
+ // SAFETY: By the safety requirements of this function, `hctx` is valid for read.
+ let ptr = unsafe { (*hctx).driver_data };
+
+ // SAFETY: By the safety requirements of this function, `ptr` came from
+ // a call to `into_foreign` in `init_hctx_callback`
+ unsafe { T::HwData::from_foreign(ptr) };
}
/// This function is called by the C kernel. A pointer to this function is
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 31/79] block: rnull: add volatile cache emulation
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (29 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 30/79] block: rust: add `hctx` " Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 32/79] block: rust: implement `Sync` for `GenDisk` Andreas Hindborg
` (47 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add volatile cache emulation to rnull. When enabled via the
`cache_size_mib` configfs attribute, writes are first stored in a volatile
cache before being written back to the simulated non-volatile storage.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 36 +++-
drivers/block/rnull/disk_storage.rs | 248 ++++++++++++++++++++++++
drivers/block/rnull/disk_storage/page.rs | 75 ++++++++
drivers/block/rnull/rnull.rs | 316 ++++++++++++++++++-------------
4 files changed, 538 insertions(+), 137 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index c08a3cbd66f18..d679f12ee6749 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -1,9 +1,11 @@
// SPDX-License-Identifier: GPL-2.0
use super::{
+ DiskStorage,
NullBlkDevice,
THIS_MODULE, //
};
+use core::fmt::Write;
use kernel::{
bindings,
block::{
@@ -19,10 +21,7 @@
AttributeOperations, //
},
configfs_attrs,
- fmt::{
- self,
- Write as _, //
- },
+ fmt,
new_mutex,
page::PAGE_SIZE,
prelude::*,
@@ -105,17 +104,19 @@ fn make_group(
badblocks: 12,
badblocks_once: 13,
badblocks_partial_io: 14,
+ cache_size_mib: 15,
],
};
+ let block_size = 4096;
Ok(configfs::Group::new(
name.try_into()?,
item_type,
// TODO: cannot coerce new_mutex!() to impl PinInit<_, Error>, so put mutex inside
- try_pin_init!( DeviceConfig {
+ try_pin_init!(DeviceConfig {
data <- new_mutex!(DeviceConfigInner {
powered: false,
- block_size: 4096,
+ block_size,
rotational: false,
disk: None,
capacity_mib: 4096,
@@ -130,6 +131,11 @@ fn make_group(
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
bad_blocks_once: false,
bad_blocks_partial_io: false,
+ disk_storage: Arc::pin_init(
+ DiskStorage::new(0, block_size as usize),
+ GFP_KERNEL
+ )?,
+ cache_size_mib: 0,
}),
}),
core::iter::empty(),
@@ -192,6 +198,8 @@ struct DeviceConfigInner {
bad_blocks: Arc<BadBlocks>,
bad_blocks_once: bool,
bad_blocks_partial_io: bool,
+ cache_size_mib: u64,
+ disk_storage: Arc<DiskStorage>,
}
#[vtable]
@@ -230,6 +238,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
bad_blocks: guard.bad_blocks.clone(),
bad_blocks_once: guard.bad_blocks_once,
bad_blocks_partial_io: guard.bad_blocks_partial_io,
+ storage: guard.disk_storage.clone(),
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -241,6 +250,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
+// DiskStorage::new(cache_size_mib << 20, block_size as usize),
configfs_simple_field!(DeviceConfig, 1, block_size, u32, check GenDiskBuilder::validate_block_size);
configfs_simple_bool_field!(DeviceConfig, 2, rotational);
configfs_simple_field!(DeviceConfig, 3, capacity_mib, u64);
@@ -433,3 +443,17 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_bool_field!(DeviceConfig, 13, bad_blocks_once);
configfs_simple_bool_field!(DeviceConfig, 14, bad_blocks_partial_io);
+configfs_attribute!(DeviceConfig, 15,
+ show: |this, page| show_field(this.data.lock().cache_size_mib, page),
+ store: |this, page| store_with_power_check(this, page, |this, page| {
+ let text = core::str::from_utf8(page)?.trim();
+ let value = text.parse::<u64>().map_err(|_| EINVAL)?;
+ let mut guard = this.data.lock();
+ guard.disk_storage = Arc::pin_init(
+ DiskStorage::new(value, guard.block_size as usize),
+ GFP_KERNEL
+ )?;
+ guard.cache_size_mib = value;
+ Ok(())
+ })
+);
diff --git a/drivers/block/rnull/disk_storage.rs b/drivers/block/rnull/disk_storage.rs
new file mode 100644
index 0000000000000..8a8a90e1cf0bd
--- /dev/null
+++ b/drivers/block/rnull/disk_storage.rs
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use super::HwQueueContext;
+use core::pin::Pin;
+use kernel::{
+ block,
+ new_spinlock,
+ new_xarray,
+ page::PAGE_SIZE,
+ prelude::*,
+ sync::{
+ atomic::{ordering, Atomic},
+ SpinLock, SpinLockGuard,
+ },
+ uapi::PAGE_SECTORS,
+ xarray::{
+ self,
+ XArray,
+ XArraySheaf, //
+ }, //
+};
+pub(crate) use page::NullBlockPage;
+
+mod page;
+
+#[pin_data]
+pub(crate) struct DiskStorage {
+ // TODO: Get rid of this pointer indirection.
+ #[pin]
+ trees: SpinLock<Pin<KBox<TreeContainer>>>,
+ cache_size: u64,
+ cache_size_used: Atomic<u64>,
+ next_flush_sector: Atomic<u64>,
+ block_size: usize,
+}
+
+impl DiskStorage {
+ pub(crate) fn new(cache_size: u64, block_size: usize) -> impl PinInit<Self, Error> {
+ try_pin_init!( Self {
+ // TODO: Get rid of the box
+ // https://git.kernel.org/pub/scm/linux/kernel/git/boqun/linux.git/commit/?h=locking&id=a5d84cafb3e253a11d2e078902c5b090be2f4227
+ trees <- new_spinlock!(KBox::pin_init(TreeContainer::new(), GFP_KERNEL)?),
+ cache_size,
+ cache_size_used: Atomic::new(0),
+ next_flush_sector: Atomic::new(0),
+ block_size
+ })
+ }
+
+ pub(crate) fn access<'a, 'b, 'c>(
+ &'a self,
+ tree_guard: &'a mut SpinLockGuard<'b, Pin<KBox<TreeContainer>>>,
+ hw_data_guard: &'a mut SpinLockGuard<'b, HwQueueContext>,
+ sheaf: Option<XArraySheaf<'c>>,
+ ) -> DiskStorageAccess<'a, 'b, 'c> {
+ DiskStorageAccess::new(self, tree_guard, hw_data_guard, sheaf)
+ }
+
+ pub(crate) fn lock(&self) -> SpinLockGuard<'_, Pin<KBox<TreeContainer>>> {
+ self.trees.lock()
+ }
+}
+
+pub(crate) struct DiskStorageAccess<'a, 'b, 'c> {
+ cache_guard: xarray::Guard<'a, TreeNode>,
+ disk_guard: xarray::Guard<'a, TreeNode>,
+ hw_data_guard: &'a mut SpinLockGuard<'b, HwQueueContext>,
+ disk_storage: &'a DiskStorage,
+ pub(crate) sheaf: Option<XArraySheaf<'c>>,
+}
+
+impl<'a, 'b, 'c> DiskStorageAccess<'a, 'b, 'c> {
+ fn new(
+ disk_storage: &'a DiskStorage,
+ tree_guard: &'a mut SpinLockGuard<'b, Pin<KBox<TreeContainer>>>,
+ hw_data_guard: &'a mut SpinLockGuard<'b, HwQueueContext>,
+ sheaf: Option<XArraySheaf<'c>>,
+ ) -> Self {
+ Self {
+ cache_guard: tree_guard.cache_tree.lock(),
+ disk_guard: tree_guard.disk_tree.lock(),
+ hw_data_guard,
+ disk_storage,
+ sheaf,
+ }
+ }
+ fn to_index(sector: u64) -> usize {
+ (sector >> block::PAGE_SECTORS_SHIFT) as usize
+ }
+
+ fn to_sector(index: usize) -> u64 {
+ (index << block::PAGE_SECTORS_SHIFT) as u64
+ }
+
+ fn extract_cache_page(&mut self) -> Result<KBox<NullBlockPage>> {
+ let cache_entry = self
+ .cache_guard
+ .find_next_entry_circular(
+ self.disk_storage.next_flush_sector.load(ordering::Relaxed) as usize
+ )
+ .expect("Expected to find a page in the cache");
+
+ let index = cache_entry.index();
+
+ self.disk_storage
+ .next_flush_sector
+ .store(Self::to_sector(index).wrapping_add(1), ordering::Relaxed);
+
+ self.disk_storage.cache_size_used.store(
+ self.disk_storage.cache_size_used.load(ordering::Relaxed) - PAGE_SIZE as u64,
+ ordering::Relaxed,
+ );
+
+ let page = match self.disk_guard.entry(index) {
+ xarray::Entry::Vacant(disk_entry) => {
+ disk_entry
+ .insert(cache_entry.remove(), self.sheaf.as_mut())
+ .expect("Preload is set up to allow insert without failure");
+ self.hw_data_guard
+ .page
+ .take()
+ .expect("Preload has allocated for us")
+ }
+ xarray::Entry::Occupied(mut disk_entry) => {
+ let mut page = if cache_entry.is_full() {
+ disk_entry.insert(cache_entry.remove())
+ } else {
+ let mut src = cache_entry;
+ let mut offset = 0;
+ for _ in 0..PAGE_SECTORS {
+ src.page_mut().get_pin_mut().copy_to_page(
+ disk_entry.page_mut().get_pin_mut(),
+ offset,
+ block::SECTOR_SIZE as usize,
+ )?;
+ offset += block::SECTOR_SIZE as usize;
+ }
+ src.remove()
+ };
+ page.reset();
+ page
+ }
+ };
+
+ Ok(page)
+ }
+
+ fn get_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
+ let index = Self::to_index(sector);
+
+ if self.cache_guard.contains_index(index) {
+ Ok(self.cache_guard.get_mut(index).expect("Index is present"))
+ } else {
+ let page = if self.disk_storage.cache_size_used.load(ordering::Relaxed)
+ < self.disk_storage.cache_size
+ {
+ self.hw_data_guard
+ .page
+ .take()
+ .expect("Expected to have a page available")
+ } else {
+ self.extract_cache_page()?
+ };
+ Ok(self
+ .cache_guard
+ .insert_entry(index, page, self.sheaf.as_mut())
+ .expect("Should be able to insert")
+ .into_mut())
+ }
+ }
+
+ fn get_disk_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
+ let index = Self::to_index(sector);
+
+ let page = match self.disk_guard.entry(index) {
+ xarray::Entry::Vacant(e) => e.insert(
+ self.hw_data_guard
+ .page
+ .take()
+ .expect("Expected page to be available"),
+ self.sheaf.as_mut(),
+ )?,
+ xarray::Entry::Occupied(e) => e.into_mut(),
+ };
+
+ Ok(page)
+ }
+
+ pub(crate) fn get_write_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
+ let page = if self.disk_storage.cache_size > 0 {
+ self.get_cache_page(sector)?
+ } else {
+ self.get_disk_page(sector)?
+ };
+
+ Ok(page)
+ }
+
+ pub(crate) fn get_read_page(&self, sector: u64) -> Option<&NullBlockPage> {
+ let index = Self::to_index(sector);
+ if self.disk_storage.cache_size > 0 {
+ self.cache_guard
+ .get(index)
+ .or_else(|| self.disk_guard.get(index))
+ } else {
+ self.disk_guard.get(index)
+ }
+ }
+
+ fn free_sector_tree(tree_access: &mut xarray::Guard<'_, TreeNode>, sector: u64) {
+ let index = Self::to_index(sector);
+ if let Some(page) = tree_access.get_mut(index) {
+ page.set_free(sector);
+
+ if page.is_empty() {
+ tree_access.remove(index);
+ }
+ }
+ }
+
+ pub(crate) fn free_sector(&mut self, sector: u64) {
+ if self.disk_storage.cache_size > 0 {
+ Self::free_sector_tree(&mut self.cache_guard, sector);
+ }
+
+ Self::free_sector_tree(&mut self.disk_guard, sector);
+ }
+}
+
+type Tree = XArray<TreeNode>;
+type TreeNode = KBox<NullBlockPage>;
+
+#[pin_data]
+pub(crate) struct TreeContainer {
+ #[pin]
+ disk_tree: Tree,
+ #[pin]
+ cache_tree: Tree,
+}
+
+impl TreeContainer {
+ fn new() -> impl PinInit<Self> {
+ pin_init!(TreeContainer {
+ disk_tree <- new_xarray!(xarray::AllocKind::Alloc),
+ cache_tree <- new_xarray!(xarray::AllocKind::Alloc),
+ })
+ }
+}
diff --git a/drivers/block/rnull/disk_storage/page.rs b/drivers/block/rnull/disk_storage/page.rs
new file mode 100644
index 0000000000000..c2e18502cbdda
--- /dev/null
+++ b/drivers/block/rnull/disk_storage/page.rs
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use kernel::{
+ block::{
+ SECTOR_MASK,
+ SECTOR_SHIFT, //
+ },
+ page::{
+ SafePage,
+ PAGE_SIZE, //
+ },
+ prelude::*,
+ types::Owned,
+ uapi::PAGE_SECTORS, //
+};
+
+const _CHEKC_STATUS_WIDTH: () = build_assert!((PAGE_SIZE >> SECTOR_SHIFT) <= 64);
+
+pub(crate) struct NullBlockPage {
+ page: Owned<SafePage>,
+ status: u64,
+ block_size: usize,
+}
+
+impl NullBlockPage {
+ pub(crate) fn new(block_size: usize) -> Result<KBox<Self>> {
+ Ok(KBox::new(
+ Self {
+ page: SafePage::alloc_page(GFP_NOIO | __GFP_ZERO)?,
+ status: 0,
+ block_size,
+ },
+ GFP_NOIO,
+ )?)
+ }
+
+ pub(crate) fn set_occupied(&mut self, sector: u64) {
+ let idx = sector & u64::from(SECTOR_MASK);
+ self.status |= 1 << idx;
+ }
+
+ pub(crate) fn set_free(&mut self, sector: u64) {
+ let idx = sector & u64::from(SECTOR_MASK);
+ self.status &= !(1 << idx);
+ }
+
+ pub(crate) fn is_empty(&self) -> bool {
+ self.status == 0
+ }
+
+ pub(crate) fn reset(&mut self) {
+ self.status = 0;
+ }
+
+ pub(crate) fn is_full(&self) -> bool {
+ let blocks_per_page = PAGE_SIZE >> self.block_size.trailing_zeros();
+ let shift = PAGE_SECTORS as usize / blocks_per_page;
+
+ for i in 0..blocks_per_page {
+ if self.status & (1 << (i * shift)) == 0 {
+ return false;
+ }
+ }
+
+ true
+ }
+
+ pub(crate) fn page_mut(&mut self) -> &mut Owned<SafePage> {
+ &mut self.page
+ }
+
+ pub(crate) fn page(&self) -> &Owned<SafePage> {
+ &self.page
+ }
+}
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 4e226186d2f36..cca497aef40df 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -3,13 +3,22 @@
//! This is a Rust implementation of the C null block driver.
mod configfs;
+mod disk_storage;
use configfs::IRQMode;
+use disk_storage::{
+ DiskStorage,
+ NullBlockPage,
+ TreeContainer, //
+};
use kernel::{
bindings,
block::{
self,
- badblocks::{self, BadBlocks},
+ badblocks::{
+ self,
+ BadBlocks, //
+ },
bio::Segment,
mq::{
self,
@@ -20,7 +29,7 @@
Operations,
TagSet, //
},
- SECTOR_MASK, SECTOR_SHIFT,
+ SECTOR_SHIFT,
},
error::{
code,
@@ -28,11 +37,7 @@
},
ffi,
new_mutex,
- new_xarray,
- page::{
- SafePage,
- PAGE_SIZE, //
- },
+ new_spinlock,
pr_info,
prelude::*,
str::CString,
@@ -41,9 +46,11 @@
atomic::{
ordering,
Atomic, //
- },
+ }, //
Arc,
- Mutex, //
+ Mutex,
+ SpinLock,
+ SpinLockGuard,
},
time::{
hrtimer::{
@@ -58,7 +65,7 @@
OwnableRefCounted,
Owned, //
},
- xarray::XArray, //
+ xarray::XArraySheaf, //
};
use pin_init::PinInit;
@@ -148,9 +155,11 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
} else {
*module_parameters::submit_queues.value()
};
+
+ let block_size = *module_parameters::bs.value();
let disk = NullBlkDevice::new(NullBlkOptions {
name: &name,
- block_size: *module_parameters::bs.value(),
+ block_size,
rotational: *module_parameters::rotational.value() != 0,
capacity_mib: *module_parameters::gb.value() * 1024,
irq_mode: (*module_parameters::irqmode.value()).try_into()?,
@@ -163,6 +172,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
bad_blocks_once: false,
bad_blocks_partial_io: false,
+ storage: Arc::pin_init(DiskStorage::new(0, block_size as usize), GFP_KERNEL)?,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -192,8 +202,20 @@ struct NullBlkOptions<'a> {
bad_blocks: Arc<BadBlocks>,
bad_blocks_once: bool,
bad_blocks_partial_io: bool,
+ storage: Arc<DiskStorage>,
+}
+
+#[pin_data]
+struct NullBlkDevice {
+ storage: Arc<DiskStorage>,
+ irq_mode: IRQMode,
+ completion_time: Delta,
+ memory_backed: bool,
+ block_size: usize,
+ bad_blocks: Arc<BadBlocks>,
+ bad_blocks_once: bool,
+ bad_blocks_partial_io: bool,
}
-struct NullBlkDevice;
impl NullBlkDevice {
fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
@@ -212,10 +234,14 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
bad_blocks,
bad_blocks_once,
bad_blocks_partial_io,
+ storage,
} = options;
let mut flags = mq::tag_set::Flags::default();
+ // TODO: lim.features |= BLK_FEAT_WRITE_CACHE;
+ // if (dev->fua)
+ // lim.features |= BLK_FEAT_FUA;
if memory_backed {
flags |= mq::tag_set::Flag::Blocking;
}
@@ -233,13 +259,13 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
GFP_KERNEL,
)?;
- let queue_data = Box::pin_init(
- pin_init!(QueueData {
- tree <- new_xarray!(kernel::xarray::AllocKind::Alloc),
+ let queue_data = Box::try_pin_init(
+ try_pin_init!(Self {
+ storage,
irq_mode,
completion_time,
memory_backed,
- block_size: block_size.into(),
+ block_size: block_size as usize,
bad_blocks,
bad_blocks_once,
bad_blocks_partial_io,
@@ -262,68 +288,133 @@ fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
builder.build(fmt!("{}", name.to_str()?), tagset, queue_data)
}
+ fn sheaf_size() -> usize {
+ 2 * ((usize::BITS as usize / bindings::XA_CHUNK_SHIFT)
+ + if (usize::BITS as usize % bindings::XA_CHUNK_SHIFT) == 0 {
+ 0
+ } else {
+ 1
+ })
+ }
+
+ fn preload<'b, 'c>(
+ tree_guard: &'b mut SpinLockGuard<'c, Pin<KBox<TreeContainer>>>,
+ hw_data_guard: &'b mut SpinLockGuard<'c, HwQueueContext>,
+ block_size: usize,
+ ) -> Result {
+ if hw_data_guard.page.is_none() {
+ hw_data_guard.page =
+ Some(tree_guard.do_unlocked(|| {
+ hw_data_guard.do_unlocked(|| NullBlockPage::new(block_size))
+ })?);
+ }
+
+ Ok(())
+ }
+
#[inline(always)]
- fn write(tree: &Tree, mut sector: u64, mut segment: Segment<'_>) -> Result {
+ fn write<'a, 'b, 'c>(
+ &'a self,
+ tree_guard: &'b mut SpinLockGuard<'c, Pin<KBox<TreeContainer>>>,
+ hw_data_guard: &'b mut SpinLockGuard<'c, HwQueueContext>,
+ mut sector: u64,
+ mut segment: Segment<'_>,
+ ) -> Result {
+ let mut sheaf: Option<XArraySheaf<'_>> = None;
+
while !segment.is_empty() {
- let page = NullBlockPage::new()?;
- let mut tree = tree.lock();
+ Self::preload(tree_guard, hw_data_guard, self.block_size)?;
- let page_idx = sector >> block::PAGE_SECTORS_SHIFT;
+ match &mut sheaf {
+ Some(sheaf) => {
+ tree_guard.do_unlocked(|| {
+ hw_data_guard.do_unlocked(|| sheaf.refill(GFP_KERNEL, Self::sheaf_size()))
+ })?;
+ }
+ None => {
+ let _ = sheaf.insert(
+ kernel::xarray::xarray_kmem_cache()
+ .sheaf(Self::sheaf_size(), GFP_NOWAIT)
+ .or(tree_guard.do_unlocked(|| {
+ hw_data_guard.do_unlocked(|| -> Result<_> {
+ kernel::xarray::xarray_kmem_cache()
+ .sheaf(Self::sheaf_size(), GFP_KERNEL)
+ })
+ }))?,
+ );
+ }
+ }
- let page = if let Some(page) = tree.get_mut(page_idx as usize) {
- page
- } else {
- tree.store(page_idx as usize, page, GFP_NOIO)?;
- tree.get_mut(page_idx as usize).unwrap()
- };
+ let mut access = self.storage.access(tree_guard, hw_data_guard, sheaf);
+ let page = access.get_write_page(sector)?;
page.set_occupied(sector);
let page_offset = (sector & u64::from(block::SECTOR_MASK)) << block::SECTOR_SHIFT;
- sector += segment.copy_to_page(page.page.get_pin_mut(), page_offset as usize) as u64
+
+ sector += segment.copy_to_page(page.page_mut().get_pin_mut(), page_offset as usize)
+ as u64
>> block::SECTOR_SHIFT;
+
+ sheaf = access.sheaf;
+ }
+
+ if let Some(sheaf) = sheaf {
+ tree_guard.do_unlocked(|| {
+ hw_data_guard.do_unlocked(|| {
+ sheaf.return_refill(GFP_KERNEL);
+ })
+ });
}
+
Ok(())
}
#[inline(always)]
- fn read(tree: &Tree, mut sector: u64, mut segment: Segment<'_>) -> Result {
- let tree = tree.lock();
+ fn read<'a, 'b, 'c>(
+ &'a self,
+ tree_guard: &'b mut SpinLockGuard<'c, Pin<KBox<TreeContainer>>>,
+ hw_data_guard: &'b mut SpinLockGuard<'c, HwQueueContext>,
+ mut sector: u64,
+ mut segment: Segment<'_>,
+ ) -> Result {
+ let access = self.storage.access(tree_guard, hw_data_guard, None);
while !segment.is_empty() {
- let idx = sector >> block::PAGE_SECTORS_SHIFT;
-
- if let Some(page) = tree.get(idx as usize) {
- let page_offset = (sector & u64::from(block::SECTOR_MASK)) << block::SECTOR_SHIFT;
- sector += segment.copy_from_page(&page.page, page_offset as usize) as u64
- >> block::SECTOR_SHIFT;
- } else {
- sector += segment.zero_page() as u64 >> block::SECTOR_SHIFT;
+ let page = access.get_read_page(sector);
+
+ match page {
+ Some(page) => {
+ let page_offset =
+ (sector & u64::from(block::SECTOR_MASK)) << block::SECTOR_SHIFT;
+ sector += segment.copy_from_page(page.page(), page_offset as usize) as u64
+ >> block::SECTOR_SHIFT;
+ }
+ None => sector += segment.zero_page() as u64 >> block::SECTOR_SHIFT,
}
}
Ok(())
}
- fn discard(tree: &Tree, mut sector: u64, sectors: u64, block_size: u64) -> Result {
- let mut remaining_bytes = sectors << SECTOR_SHIFT;
- let mut tree = tree.lock();
+ fn discard(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ mut sector: u64,
+ sectors: u32,
+ ) -> Result {
+ let mut tree_guard = self.storage.lock();
+ let mut hw_data_guard = hw_data.lock();
- while remaining_bytes > 0 {
- let page_idx = sector >> block::PAGE_SECTORS_SHIFT;
- let mut remove = false;
- if let Some(page) = tree.get_mut(page_idx as usize) {
- page.set_free(sector);
- if page.is_empty() {
- remove = true;
- }
- }
+ let mut access = self
+ .storage
+ .access(&mut tree_guard, &mut hw_data_guard, None);
- if remove {
- drop(tree.remove(page_idx as usize))
- }
+ let mut remaining_bytes = (sectors as usize) << SECTOR_SHIFT;
- let processed = remaining_bytes.min(block_size);
- sector += processed >> SECTOR_SHIFT;
+ while remaining_bytes > 0 {
+ access.free_sector(sector);
+ let processed = remaining_bytes.min(self.block_size);
+ sector += (processed >> SECTOR_SHIFT) as u64;
remaining_bytes -= processed;
}
@@ -331,21 +422,34 @@ fn discard(tree: &Tree, mut sector: u64, sectors: u64, block_size: u64) -> Resul
}
#[inline(never)]
- fn transfer(rq: &mut Owned<mq::Request<Self>>, tree: &Tree, sectors: u32) -> Result {
+ fn transfer(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ rq: &mut Owned<mq::Request<Self>>,
+ sectors: u32,
+ ) -> Result {
let mut sector = rq.sector();
let end_sector = sector + <u32 as Into<u64>>::into(sectors);
let command = rq.command();
+ // TODO: Use `PerCpu` to get rid of this lock
+ let mut hw_data_guard = hw_data.lock();
+ let mut tree_guard = self.storage.lock();
+
for bio in rq.bio_iter_mut() {
let segment_iter = bio.segment_iter();
for segment in segment_iter {
// Length might be limited by bad blocks.
let length = segment
.len()
- .min((sector - end_sector) as u32 >> SECTOR_SHIFT);
+ .min((end_sector - sector) as u32 >> SECTOR_SHIFT);
match command {
- bindings::req_op_REQ_OP_WRITE => Self::write(tree, sector, segment)?,
- bindings::req_op_REQ_OP_READ => Self::read(tree, sector, segment)?,
+ bindings::req_op_REQ_OP_WRITE => {
+ self.write(&mut tree_guard, &mut hw_data_guard, sector, segment)?
+ }
+ bindings::req_op_REQ_OP_READ => {
+ self.read(&mut tree_guard, &mut hw_data_guard, sector, segment)?
+ }
_ => (),
}
sector += u64::from(length) >> SECTOR_SHIFT;
@@ -355,29 +459,26 @@ fn transfer(rq: &mut Owned<mq::Request<Self>>, tree: &Tree, sectors: u32) -> Res
}
}
}
+
Ok(())
}
- fn handle_bad_blocks(
- rq: &mut Owned<mq::Request<Self>>,
- queue_data: &QueueData,
- sectors: &mut u32,
- ) -> Result {
- if queue_data.bad_blocks.enabled() {
+ fn handle_bad_blocks(&self, rq: &mut Owned<mq::Request<Self>>, sectors: &mut u32) -> Result {
+ if self.bad_blocks.enabled() {
let start = rq.sector();
let end = start + u64::from(*sectors);
- match queue_data.bad_blocks.check(start..end) {
+ match self.bad_blocks.check(start..end) {
badblocks::BlockStatus::None => {}
badblocks::BlockStatus::Acknowledged(mut range)
| badblocks::BlockStatus::Unacknowledged(mut range) => {
rq.data_ref().error.store(1, ordering::Relaxed);
- if queue_data.bad_blocks_once {
- queue_data.bad_blocks.set_good(range.clone())?;
+ if self.bad_blocks_once {
+ self.bad_blocks.set_good(range.clone())?;
}
- if queue_data.bad_blocks_partial_io {
- let block_size_sectors = queue_data.block_size >> SECTOR_SHIFT;
+ if self.bad_blocks_partial_io {
+ let block_size_sectors = (self.block_size >> SECTOR_SHIFT) as u64;
range.start = align_down(range.start, block_size_sectors);
if start < range.start {
*sectors = (range.start - start) as u32;
@@ -402,53 +503,8 @@ fn end_request(rq: Owned<mq::Request<Self>>) {
}
}
-const _CHEKC_STATUS_WIDTH: () = build_assert!((PAGE_SIZE >> SECTOR_SHIFT) <= 64);
-
-struct NullBlockPage {
- page: Owned<SafePage>,
- status: u64,
-}
-
-impl NullBlockPage {
- fn new() -> Result<KBox<Self>> {
- Ok(KBox::new(
- Self {
- page: SafePage::alloc_page(GFP_NOIO | __GFP_ZERO)?,
- status: 0,
- },
- GFP_NOIO,
- )?)
- }
-
- fn set_occupied(&mut self, sector: u64) {
- let idx = sector & u64::from(SECTOR_MASK);
- self.status |= 1 << idx;
- }
-
- fn set_free(&mut self, sector: u64) {
- let idx = sector & u64::from(SECTOR_MASK);
- self.status &= !(1 << idx);
- }
-
- fn is_empty(&self) -> bool {
- self.status == 0
- }
-}
-
-type TreeNode = KBox<NullBlockPage>;
-type Tree = XArray<TreeNode>;
-
-#[pin_data]
-struct QueueData {
- #[pin]
- tree: Tree,
- irq_mode: IRQMode,
- completion_time: Delta,
- memory_backed: bool,
- block_size: u64,
- bad_blocks: Arc<BadBlocks>,
- bad_blocks_once: bool,
- bad_blocks_partial_io: bool,
+struct HwQueueContext {
+ page: Option<KBox<disk_storage::NullBlockPage>>,
}
#[pin_data]
@@ -503,10 +559,10 @@ fn align_down<T>(value: T, to: T) -> T
#[vtable]
impl Operations for NullBlkDevice {
- type QueueData = Pin<KBox<QueueData>>;
+ type QueueData = Pin<KBox<Self>>;
type RequestData = Pdu;
type TagSetData = ();
- type HwData = ();
+ type HwData = Pin<KBox<SpinLock<HwQueueContext>>>;
fn new_request_data() -> impl PinInit<Self::RequestData> {
pin_init!(Pdu {
@@ -517,41 +573,39 @@ fn new_request_data() -> impl PinInit<Self::RequestData> {
#[inline(always)]
fn queue_rq(
- _hw_data: (),
- queue_data: Pin<&QueueData>,
+ hw_data: Pin<&SpinLock<HwQueueContext>>,
+ this: Pin<&Self>,
mut rq: Owned<mq::Request<Self>>,
_is_last: bool,
) -> Result {
let mut sectors = rq.sectors();
- Self::handle_bad_blocks(&mut rq, queue_data.get_ref(), &mut sectors)?;
-
- if queue_data.memory_backed {
- let tree = &queue_data.tree;
+ Self::handle_bad_blocks(this.get_ref(), &mut rq, &mut sectors)?;
+ if this.memory_backed {
if rq.command() == bindings::req_op_REQ_OP_DISCARD {
- Self::discard(tree, rq.sector(), sectors.into(), queue_data.block_size)?;
+ this.discard(&hw_data, rq.sector(), sectors)?;
} else {
- Self::transfer(&mut rq, tree, sectors)?;
+ this.transfer(&hw_data, &mut rq, sectors)?;
}
}
- match queue_data.irq_mode {
+ match this.irq_mode {
IRQMode::None => Self::end_request(rq),
IRQMode::Soft => mq::Request::complete(rq.into()),
IRQMode::Timer => {
OwnableRefCounted::into_shared(rq)
- .start(queue_data.completion_time)
+ .start(this.completion_time)
.dismiss();
}
}
Ok(())
}
- fn commit_rqs(_hw_data: (), _queue_data: Pin<&QueueData>) {}
+ fn commit_rqs(_hw_data: Pin<&SpinLock<HwQueueContext>>, _queue_data: Pin<&Self>) {}
- fn init_hctx(_tagset_data: (), _hctx_idx: u32) -> Result {
- Ok(())
+ fn init_hctx(_tagset_data: (), _hctx_idx: u32) -> Result<Self::HwData> {
+ KBox::pin_init(new_spinlock!(HwQueueContext { page: None }), GFP_KERNEL)
}
fn complete(rq: ARef<mq::Request<Self>>) {
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 32/79] block: rust: implement `Sync` for `GenDisk`.
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (30 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 31/79] block: rnull: add volatile cache emulation Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 33/79] block: rust: add a back reference feature to `GenDisk` Andreas Hindborg
` (46 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
`GenDisk` is a pointer to a `struct gendisk`. It is safe to reference this
struct from multiple threads.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/gen_disk.rs | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 75968d6a57639..72bbf3cadfe82 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -218,6 +218,10 @@ pub struct GenDisk<T: Operations> {
// `TagSet` It is safe to send this to other threads as long as T is Send.
unsafe impl<T: Operations + Send> Send for GenDisk<T> {}
+// SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a `TagSet`. It is
+// safe to reference these from multiple threads.
+unsafe impl<T: Operations> Sync for GenDisk<T> {}
+
impl<T: Operations> Drop for GenDisk<T> {
fn drop(&mut self) {
// SAFETY: By type invariant of `Self`, `self.gendisk` points to a valid
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 33/79] block: rust: add a back reference feature to `GenDisk`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (31 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 32/79] block: rust: implement `Sync` for `GenDisk` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 34/79] block: rust: introduce an idle type state for `Request` Andreas Hindborg
` (45 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
During certain block layer callbacks, drivers may need access to the Rust
`GenDisk` representing a disk the driver is managing. In some situations it
is only possible to obtain a pointer to the C `struct gendisk`. With the
current setup, it is not possible to obtain the `GenDisk` for this C
`gendisk`. To circumvent this, we add a back reference feature to the
`GenDisk` so that we can store a reference counted reference to the
`GenDisk` somewhere easily accessible.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 2 +-
drivers/block/rnull/rnull.rs | 4 +--
rust/kernel/block/mq/gen_disk.rs | 62 ++++++++++++++++++++++++++++++++++++----
3 files changed, 59 insertions(+), 9 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index d679f12ee6749..e365eb06be6de 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -189,7 +189,7 @@ struct DeviceConfigInner {
capacity_mib: u64,
irq_mode: IRQMode,
completion_time: time::Delta,
- disk: Option<GenDisk<NullBlkDevice>>,
+ disk: Option<Arc<GenDisk<NullBlkDevice>>>,
memory_backed: bool,
submit_queues: u32,
home_node: i32,
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index cca497aef40df..aa59ede72e495 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -136,7 +136,7 @@ struct NullBlkModule {
#[pin]
configfs_subsystem: kernel::configfs::Subsystem<configfs::Config>,
#[pin]
- param_disks: Mutex<KVec<GenDisk<NullBlkDevice>>>,
+ param_disks: Mutex<KVec<Arc<GenDisk<NullBlkDevice>>>>,
}
impl kernel::InPlaceModule for NullBlkModule {
@@ -218,7 +218,7 @@ struct NullBlkDevice {
}
impl NullBlkDevice {
- fn new(options: NullBlkOptions<'_>) -> Result<GenDisk<Self>> {
+ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
let NullBlkOptions {
name,
block_size,
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 72bbf3cadfe82..8d39bb70725b0 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -11,11 +11,13 @@
error::{self, from_err_ptr, Result},
fmt::{self, Write},
prelude::*,
+ revocable::Revocable,
static_lock_class,
str::NullTerminatedFormatter,
- sync::Arc,
+ sync::{Arc, UniqueArc},
types::{ForeignOwnable, ScopeGuard},
};
+use core::ptr::NonNull;
/// A builder for [`GenDisk`].
///
@@ -112,7 +114,7 @@ pub fn build<T: Operations>(
name: fmt::Arguments<'_>,
tagset: Arc<TagSet<T>>,
queue_data: T::QueueData,
- ) -> Result<GenDisk<T>> {
+ ) -> Result<Arc<GenDisk<T>>> {
let data = queue_data.into_foreign();
let recover_data = ScopeGuard::new(|| {
// SAFETY: T::QueueData was created by the call to `into_foreign()` above
@@ -194,10 +196,28 @@ pub fn build<T: Operations>(
// INVARIANT: `gendisk` was added to the VFS via `device_add_disk` above.
// INVARIANT: `gendisk.queue.queue_data` is set to `data` in the call to
// `__blk_mq_alloc_disk` above.
- Ok(GenDisk {
- _tagset: tagset,
- gendisk,
- })
+ let mut disk = UniqueArc::new(
+ GenDisk {
+ _tagset: tagset,
+ gendisk,
+ backref: Arc::pin_init(
+ // INVARIANT: We break `GenDiskRef` invariant here, but we restore it below.
+ Revocable::new(GenDiskRef(NonNull::dangling())),
+ GFP_KERNEL,
+ )?,
+ },
+ GFP_KERNEL,
+ )?;
+
+ disk.backref = Arc::pin_init(
+ // INVARIANT: The `GenDisk` in `disk` is a valid for use as a reference.
+ Revocable::new(GenDiskRef(
+ NonNull::new(disk.as_ptr().cast_mut()).expect("Should not be null"),
+ )),
+ GFP_KERNEL,
+ )?;
+
+ Ok(disk.into())
}
}
@@ -212,6 +232,14 @@ pub fn build<T: Operations>(
pub struct GenDisk<T: Operations> {
_tagset: Arc<TagSet<T>>,
gendisk: *mut bindings::gendisk,
+ backref: Arc<Revocable<GenDiskRef<T>>>,
+}
+
+impl<T: Operations> GenDisk<T> {
+ /// Get a `GenDiskRef` referencing this `GenDisk`.
+ pub fn get_ref(&self) -> Arc<Revocable<GenDiskRef<T>>> {
+ self.backref.clone()
+ }
}
// SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a
@@ -241,3 +269,25 @@ fn drop(&mut self) {
drop(unsafe { T::QueueData::from_foreign(queue_data) });
}
}
+
+/// A reference to a `GenDisk`.
+///
+/// # Invariants
+///
+/// `self.0` is valid for use as a reference.
+pub struct GenDiskRef<T: Operations>(NonNull<GenDisk<T>>);
+
+// SAFETY: It is safe to transfer ownership of `GenDiskRef` across thread boundaries.
+unsafe impl<T: Operations> Send for GenDiskRef<T> {}
+
+// SAFETY: It is safe to share references to `GenDiskRef` across thread boundaries.
+unsafe impl<T: Operations> Sync for GenDiskRef<T> {}
+
+impl<T: Operations> core::ops::Deref for GenDiskRef<T> {
+ type Target = GenDisk<T>;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: By type invariant, `self.0` is valid for use as a reference.
+ unsafe { self.0.as_ref() }
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 34/79] block: rust: introduce an idle type state for `Request`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (32 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 33/79] block: rust: add a back reference feature to `GenDisk` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 35/79] block: rust: add a request queue abstraction Andreas Hindborg
` (44 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Block device drivers need to invoke `blk_mq_start_request` on a request to
indicate that they have started processing the request. This function may
only be called once after a request has been issued to a driver. For Rust
block device drivers, the Rust abstractions handle this call. However, in
some situations a driver may want to control when a request is started.
Thus, expose the start method to Rust block device drivers.
To ensure the method is not called more than once, introduce a type state
for `Request`. Requests are issued as `IdleRequest` and transition to
`Request` when the `start` method is called.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 3 +-
rust/kernel/block/mq.rs | 5 +-
rust/kernel/block/mq/operations.rs | 13 ++--
rust/kernel/block/mq/request.rs | 155 ++++++++++++++++++++++++++++++-------
4 files changed, 136 insertions(+), 40 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index aa59ede72e495..034ddc06eabf9 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -575,9 +575,10 @@ fn new_request_data() -> impl PinInit<Self::RequestData> {
fn queue_rq(
hw_data: Pin<&SpinLock<HwQueueContext>>,
this: Pin<&Self>,
- mut rq: Owned<mq::Request<Self>>,
+ rq: Owned<mq::IdleRequest<Self>>,
_is_last: bool,
) -> Result {
+ let mut rq = rq.start();
let mut sectors = rq.sectors();
Self::handle_bad_blocks(this.get_ref(), &mut rq, &mut sectors)?;
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 3eab3ca8f5480..ab493bd91af4c 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -88,10 +88,10 @@
//! fn queue_rq(
//! _hw_data: (),
//! _queue_data: (),
-//! rq: Owned<Request<Self>>,
+//! rq: Owned<IdleRequest<Self>>,
//! _is_last: bool
//! ) -> Result {
-//! rq.end_ok();
+//! rq.start().end_ok();
//! Ok(())
//! }
//!
@@ -130,6 +130,7 @@
pub mod tag_set;
pub use operations::Operations;
+pub use request::IdleRequest;
pub use request::Request;
pub use request::RequestTimerHandle;
pub use tag_set::TagSet;
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 6641c340d87f4..fb75d65f67071 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -6,13 +6,13 @@
use crate::{
bindings,
- block::mq::{request::RequestDataWrapper, Request},
+ block::mq::{request::RequestDataWrapper, IdleRequest, Request},
error::{from_result, Result},
prelude::*,
sync::{aref::ARef, atomic::ordering, Refcount},
types::{ForeignOwnable, Owned},
};
-use core::{marker::PhantomData, ptr::NonNull};
+use core::marker::PhantomData;
use pin_init::PinInit;
type ForeignBorrowed<'a, T> = <T as ForeignOwnable>::Borrowed<'a>;
@@ -60,7 +60,7 @@ pub trait Operations: Sized {
fn queue_rq(
hw_data: ForeignBorrowed<'_, Self::HwData>,
queue_data: ForeignBorrowed<'_, Self::QueueData>,
- rq: Owned<Request<Self>>,
+ rq: Owned<IdleRequest<Self>>,
is_last: bool,
) -> Result;
@@ -132,14 +132,14 @@ impl<T: Operations> OperationsVTable<T> {
== 0
);
+ // INVARIANT: By C API contract, `bd.rq` has not been started yet.
// SAFETY:
// - By API contract, we own the request.
// - By the safety requirements of this function, `request` is a valid
// `struct request` and the private data is properly initialized.
// - `rq` will be alive until `blk_mq_end_request` is called and is
// reference counted by until then.
- let mut rq =
- unsafe { Owned::from_raw(NonNull::<Request<T>>::new_unchecked((*bd).rq.cast())) };
+ let rq = unsafe { IdleRequest::from_raw((*bd).rq) };
// SAFETY: The safety requirement for this function ensure that `hctx`
// is valid and that `driver_data` was produced by a call to
@@ -155,9 +155,6 @@ impl<T: Operations> OperationsVTable<T> {
// dropped, which happens after we are dropped.
let queue_data = unsafe { T::QueueData::borrow(queue_data) };
- // SAFETY: We have exclusive access and we just set the refcount above.
- unsafe { rq.start_unchecked() };
-
let ret = T::queue_rq(
hw_data,
queue_data,
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 38289b9f966fa..f6addd20624a9 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -15,13 +15,111 @@
time::hrtimer::{
HasHrTimer, HrTimer, HrTimerCallback, HrTimerHandle, HrTimerMode, HrTimerPointer,
},
- types::{Opaque, Ownable, OwnableRefCounted, Owned},
+ types::{ForeignOwnable, Opaque, Ownable, OwnableRefCounted, Owned},
};
-use core::{ffi::c_void, marker::PhantomData, ptr::NonNull};
+use core::{ffi::c_void, marker::PhantomData, ops::Deref, ptr::NonNull};
use crate::block::bio::Bio;
use crate::block::bio::BioIterator;
+/// A [`Request`] that a driver has not yet begun to process.
+///
+/// A driver can convert an `IdleRequest` to a [`Request`] by calling [`IdleRequest::start`].
+///
+/// # Invariants
+///
+/// - This request has not been started yet.
+#[repr(transparent)]
+pub struct IdleRequest<T>(RequestInner<T>);
+
+impl<T: Operations> IdleRequest<T> {
+ /// Mark the request as processing.
+ ///
+ /// This converts the [`IdleRequest`] into a [`Request`].
+ pub fn start(self: Owned<Self>) -> Owned<Request<T>> {
+ // SAFETY: By type invariant `self.0.0` is a valid request. Because we have an `Owned<_>`,
+ // the refcount is zero.
+ let mut request = unsafe { Request::from_raw(self.0 .0.get()) };
+
+ debug_assert!(
+ request
+ .wrapper_ref()
+ .refcount()
+ .as_atomic()
+ .load(ordering::Acquire)
+ == 0
+ );
+
+ // SAFETY: We have exclusive access and the refcount is 0. By type invariant `request` was
+ // not started yet.
+ unsafe { request.start_unchecked() };
+
+ request
+ }
+
+ /// Create a [`Self`] from a raw request pointer.
+ ///
+ /// # Safety
+ ///
+ /// - The request pointed to by `ptr` must satisfythe invariants of both [`Request`] and
+ /// [`Self`].
+ /// - The refcount of the request pointed to by `ptr` must be 0.
+ pub(crate) unsafe fn from_raw(ptr: *mut bindings::request) -> Owned<Self> {
+ // SAFETY: By function safety requirements, `ptr` is valid for use as an `IdleRequest`.
+ unsafe { Owned::from_raw(NonNull::<Self>::new_unchecked(ptr.cast())) }
+ }
+}
+
+// SAFETY: The `release` implementation leaks the `IdleRequest`, which is a valid state for a
+// [`Request`] with refcount 0.
+unsafe impl<T: Operations> Ownable for IdleRequest<T> {
+ unsafe fn release(_this: NonNull<Self>) {}
+}
+
+impl<T: Operations> Deref for IdleRequest<T> {
+ type Target = RequestInner<T>;
+
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+}
+
+pub struct RequestInner<T>(Opaque<bindings::request>, PhantomData<T>);
+
+impl<T: Operations> RequestInner<T> {
+ /// Get the command identifier for the request
+ pub fn command(&self) -> u32 {
+ // SAFETY: By C API contract and type invariant, `cmd_flags` is valid for read
+ unsafe { (*self.0.get()).cmd_flags & ((1 << bindings::REQ_OP_BITS) - 1) }
+ }
+
+ /// Get the target sector for the request.
+ #[inline(always)]
+ pub fn sector(&self) -> u64 {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
+ unsafe { (*self.0.get()).__sector }
+ }
+
+ /// Get the size of the request in number of sectors.
+ #[inline(always)]
+ pub fn sectors(&self) -> u32 {
+ self.bytes() >> crate::block::SECTOR_SHIFT
+ }
+
+ /// Get the size of the request in bytes.
+ #[inline(always)]
+ pub fn bytes(&self) -> u32 {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
+ unsafe { (*self.0.get()).__data_len }
+ }
+
+ /// Borrow the queue data from the request queue associated with this request.
+ pub fn queue_data(&self) -> <T::QueueData as ForeignOwnable>::Borrowed<'_> {
+ // SAFETY: By type invariants of `Request`, `self.0` is a valid request.
+ unsafe { T::QueueData::borrow((*(*self.0.get()).q).queuedata) }
+ }
+}
+
/// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
///
/// # Implementation details
@@ -58,9 +156,28 @@
/// [`struct request`]: srctree/include/linux/blk-mq.h
///
#[repr(transparent)]
-pub struct Request<T>(Opaque<bindings::request>, PhantomData<T>);
+pub struct Request<T>(RequestInner<T>);
+
+impl<T: Operations> Deref for Request<T> {
+ type Target = RequestInner<T>;
+
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+}
impl<T: Operations> Request<T> {
+ /// Create a `Owned<Request>` from a request pointer.
+ ///
+ /// # Safety
+ ///
+ /// - `ptr` must satisfy invariants of `Request`.
+ /// - The refcount of the request pointed to by `ptr` must be 0.
+ pub(crate) unsafe fn from_raw(ptr: *mut bindings::request) -> Owned<Self> {
+ // SAFETY: By function safety requirements, `ptr` is valid for use as `Owned<Request>`.
+ unsafe { Owned::from_raw(NonNull::<Self>::new_unchecked(ptr.cast())) }
+ }
+
/// Create an [`ARef<Request>`] from a [`struct request`] pointer.
///
/// # Safety
@@ -78,12 +195,6 @@ pub(crate) unsafe fn aref_from_raw(ptr: *mut bindings::request) -> ARef<Self> {
unsafe { ARef::from_raw(NonNull::new_unchecked(ptr.cast())) }
}
- /// Get the command identifier for the request
- pub fn command(&self) -> u32 {
- // SAFETY: By C API contract and type invariant, `cmd_flags` is valid for read
- unsafe { (*self.0.get()).cmd_flags & ((1 << bindings::REQ_OP_BITS) - 1) }
- }
-
/// Complete the request by scheduling `Operations::complete` for
/// execution.
///
@@ -106,7 +217,7 @@ pub fn complete(this: ARef<Self>) {
pub fn bio(&self) -> Option<&Bio> {
// SAFETY: By type invariant of `Self`, `self.0` is valid and the deref
// is safe.
- let ptr = unsafe { (*self.0.get()).bio };
+ let ptr = unsafe { (*self.0 .0.get()).bio };
// SAFETY: By C API contract, if `bio` is not null it will have a
// positive refcount at least for the duration of the lifetime of
// `&self`.
@@ -118,7 +229,7 @@ pub fn bio(&self) -> Option<&Bio> {
pub fn bio_mut(&mut self) -> Option<&mut Bio> {
// SAFETY: By type invariant of `Self`, `self.0` is valid and the deref
// is safe.
- let ptr = unsafe { (*self.0.get()).bio };
+ let ptr = unsafe { (*self.0 .0.get()).bio };
// SAFETY: By C API contract, if `bio` is not null it will have a
// positive refcount at least for the duration of the lifetime of
// `&self`.
@@ -132,25 +243,11 @@ pub fn bio_iter_mut<'a>(self: &'a mut Owned<Self>) -> BioIterator<'a> {
// `NonNull::new` will return `None` if the pointer is null.
BioIterator {
// SAFETY: By type invariant `self.0` is a valid `struct request`.
- bio: NonNull::new(unsafe { (*self.0.get()).bio.cast() }),
+ bio: NonNull::new(unsafe { (*self.0 .0.get()).bio.cast() }),
_p: PhantomData,
}
}
- /// Get the target sector for the request.
- #[inline(always)]
- pub fn sector(&self) -> u64 {
- // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
- unsafe { (*self.0.get()).__sector }
- }
-
- /// Get the size of the request in number of sectors.
- #[inline(always)]
- pub fn sectors(&self) -> u32 {
- // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
- (unsafe { (*self.0.get()).__data_len }) >> crate::block::SECTOR_SHIFT
- }
-
/// Return a pointer to the [`RequestDataWrapper`] stored in the private area
/// of the request structure.
///
@@ -289,10 +386,10 @@ impl<T: Operations> Owned<Request<T>> {
/// `self.wrapper_ref().refcount() == 0`.
///
/// This can only be called once in the request life cycle.
- pub(crate) unsafe fn start_unchecked(&mut self) {
+ pub unsafe fn start_unchecked(&mut self) {
// SAFETY: By type invariant, `self.0` is a valid `struct request` and
// we have exclusive access.
- unsafe { bindings::blk_mq_start_request(self.0.get()) };
+ unsafe { bindings::blk_mq_start_request(self.0 .0.get()) };
}
/// Notify the block layer that the request has been completed without errors.
@@ -302,7 +399,7 @@ pub fn end_ok(self) {
/// Notify the block layer that the request has been completed.
pub fn end(self, status: u8) {
- let request_ptr = self.0.get().cast();
+ let request_ptr = self.0 .0.get().cast();
core::mem::forget(self);
// SAFETY: By type invariant, `this.0` was a valid `struct request`. The
// existence of `self` guarantees that there are no `ARef`s pointing to
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 35/79] block: rust: add a request queue abstraction
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (33 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 34/79] block: rust: introduce an idle type state for `Request` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 36/79] block: rust: add a method to get the request queue for a request Andreas Hindborg
` (43 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add the `RequestQueue` type as a Rust abstraction for `struct
request_queue`. This type provides methods to access the request queue
associated with a `GenDisk` or `Request`.
The abstraction exposes queue-related functionality needed by block
device drivers.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq.rs | 2 ++
rust/kernel/block/mq/gen_disk.rs | 8 ++++-
rust/kernel/block/mq/request_queue.rs | 57 +++++++++++++++++++++++++++++++++++
3 files changed, 66 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index ab493bd91af4c..a898dda2635e5 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -127,10 +127,12 @@
pub mod gen_disk;
mod operations;
mod request;
+mod request_queue;
pub mod tag_set;
pub use operations::Operations;
pub use request::IdleRequest;
pub use request::Request;
pub use request::RequestTimerHandle;
+pub use request_queue::RequestQueue;
pub use tag_set::TagSet;
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 8d39bb70725b0..8a22767f1b916 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -7,7 +7,7 @@
use crate::{
bindings,
- block::mq::{Operations, TagSet},
+ block::mq::{Operations, RequestQueue, TagSet},
error::{self, from_err_ptr, Result},
fmt::{self, Write},
prelude::*,
@@ -240,6 +240,12 @@ impl<T: Operations> GenDisk<T> {
pub fn get_ref(&self) -> Arc<Revocable<GenDiskRef<T>>> {
self.backref.clone()
}
+
+ /// Get the [`RequestQueue`] associated with this [`GenDisk`].
+ pub fn queue(&self) -> &RequestQueue<T> {
+ // SAFETY: By type invariant, self is a valid gendisk.
+ unsafe { RequestQueue::from_raw((*self.gendisk).queue) }
+ }
}
// SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a
diff --git a/rust/kernel/block/mq/request_queue.rs b/rust/kernel/block/mq/request_queue.rs
new file mode 100644
index 0000000000000..7d846ea423730
--- /dev/null
+++ b/rust/kernel/block/mq/request_queue.rs
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use super::Operations;
+use crate::types::{ForeignOwnable, Opaque};
+use core::marker::PhantomData;
+
+/// A structure describing the queues associated with a block device.
+///
+/// Owned by a [`GenDisk`].
+///
+/// # Invariants
+///
+/// - `self.0` is a valid `bindings::request_queue`.
+/// - `self.0.queuedata` is a valid `T::QueueData`.
+#[repr(transparent)]
+pub struct RequestQueue<T>(Opaque<bindings::request_queue>, PhantomData<T>);
+
+impl<T> RequestQueue<T>
+where
+ T: Operations,
+{
+ /// Create a [`RequestQueue`] from a raw `bindings::request_queue` pointer
+ ///
+ /// # Safety
+ ///
+ /// - `ptr` must be valid for use as a reference for the duration of `'a`.
+ /// - `ptr` must have been initialized as part of [`GenDiskBuilder::build`].
+ pub(crate) unsafe fn from_raw<'a>(ptr: *const bindings::request_queue) -> &'a Self {
+ // INVARIANT:
+ // - By function safety requirements, `ptr` is a valid `request_queue`.
+ // - By function safety requirement `ptr` was initialized by [`GenDiskBuilder::build`], and
+ // thus `queuedata` was set to point to a valid `T::QueueData`.
+ //
+ // SAFETY: By function safety requirements `ptr` is valid for use as a reference.
+ unsafe { &*ptr.cast() }
+ }
+
+ /// Get the driver private data associated with this [`RequestQueue`].
+ pub fn queue_data(&self) -> <T::QueueData as ForeignOwnable>::Borrowed<'_> {
+ // SAFETY: By type invariant, `queuedata` is a valid `T::QueueData`.
+ unsafe { T::QueueData::borrow((*self.0.get()).queuedata) }
+ }
+
+ /// Stop all hardware queues of this [`RequestQueue`].
+ pub fn stop_hw_queues(&self) {
+ // SAFETY: By type invariant, `self.0` is a valid `request_queue`.
+ unsafe { bindings::blk_mq_stop_hw_queues(self.0.get()) }
+ }
+
+ /// Start all hardware queues of this [`RequestQueue`].
+ ///
+ /// This function will mark the queues as ready and if necessary, schedule the queues to run.
+ pub fn start_stopped_hw_queues_async(&self) {
+ // SAFETY: By type invariant, `self.0` is a valid `request_queue`.
+ unsafe { bindings::blk_mq_start_stopped_hw_queues(self.0.get(), true) }
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 36/79] block: rust: add a method to get the request queue for a request
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (34 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 35/79] block: rust: add a request queue abstraction Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 37/79] block: rust: introduce `kernel::block::error` Andreas Hindborg
` (42 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method to `Request` for obtaining the associated `RequestQueue`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index f6addd20624a9..d6f3ffde1c5c4 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -19,6 +19,7 @@
};
use core::{ffi::c_void, marker::PhantomData, ops::Deref, ptr::NonNull};
+use super::RequestQueue;
use crate::block::bio::Bio;
use crate::block::bio::BioIterator;
@@ -118,6 +119,12 @@ pub fn queue_data(&self) -> <T::QueueData as ForeignOwnable>::Borrowed<'_> {
// SAFETY: By type invariants of `Request`, `self.0` is a valid request.
unsafe { T::QueueData::borrow((*(*self.0.get()).q).queuedata) }
}
+
+ /// Get the request queue associated with this request.
+ pub fn queue(&self) -> &RequestQueue<T> {
+ // SAFETY: By type invariant, self.0 is guaranteed to be valid.
+ unsafe { RequestQueue::from_raw((*self.0.get()).q) }
+ }
}
/// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 37/79] block: rust: introduce `kernel::block::error`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (35 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 36/79] block: rust: add a method to get the request queue for a request Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 38/79] block: rust: require `queue_rq` to return a `BlkResult` Andreas Hindborg
` (41 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Block layer status codes, represented by `blk_status_t`, are only one
byte. This is different from the general kernel error codes.
Add `BlkError` and `BlkResult` to handle these status codes.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block.rs | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++
rust/kernel/error.rs | 3 +-
2 files changed, 96 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/block.rs b/rust/kernel/block.rs
index 19236ab95227b..6cd83dc75a5eb 100644
--- a/rust/kernel/block.rs
+++ b/rust/kernel/block.rs
@@ -18,3 +18,97 @@
/// The difference between the size of a page and the size of a sector,
/// expressed as a power of two.
pub const PAGE_SECTORS_SHIFT: u32 = bindings::PAGE_SECTORS_SHIFT;
+
+pub mod error {
+ //! Block layer errors.
+
+ use core::num::NonZeroU8;
+
+ pub mod code {
+ //! C compatible error codes for the block subsystem.
+ macro_rules! declare_err {
+ ($err:tt $(,)? $($doc:expr),+) => {
+ $(
+ #[doc = $doc]
+ )*
+ pub const $err: super::BlkError =
+ match super::BlkError::try_from_blk_status(crate::bindings::$err as u8) {
+ Some(err) => err,
+ None => panic!("Invalid errno in `declare_err!`"),
+ };
+ };
+ }
+
+ declare_err!(BLK_STS_NOTSUPP, "Operation not supported.");
+ declare_err!(BLK_STS_IOERR, "Generic IO error.");
+ declare_err!(BLK_STS_DEV_RESOURCE, "Device resource busy. Retry later.");
+ }
+
+ /// A wrapper around a 1 byte block layer error code.
+ #[derive(Clone, Copy, PartialEq, Eq)]
+ pub struct BlkError(NonZeroU8);
+
+ impl BlkError {
+ /// Create a [`BlkError`] from a `blk_status_t`.
+ ///
+ /// If the code is not know, this function will warn and return [`code::BLK_STS_IOERR`].
+ pub fn from_blk_status(status: bindings::blk_status_t) -> Self {
+ if let Some(error) = Self::try_from_blk_status(status) {
+ error
+ } else {
+ kernel::pr_warn!("Attempted to create `BlkError` from invalid value");
+ code::BLK_STS_IOERR
+ }
+ }
+
+ /// Convert `Self` to the underlying type.
+ pub fn to_blk_status(self) -> bindings::blk_status_t {
+ self.0.into()
+ }
+
+ /// Try to create a `Self` form a `blk_status_t`.
+ ///
+ /// Returns `None` if the conversion fails.
+ const fn try_from_blk_status(errno: bindings::blk_status_t) -> Option<Self> {
+ if errno == 0 {
+ None
+ } else {
+ Some(BlkError(
+ // SAFETY: We just checked that `errno`is nonzero.
+ unsafe { NonZeroU8::new_unchecked(errno) },
+ ))
+ }
+ }
+ }
+
+ impl From<BlkError> for u8 {
+ fn from(value: BlkError) -> Self {
+ value.0.into()
+ }
+ }
+
+ impl From<BlkError> for u32 {
+ fn from(value: BlkError) -> Self {
+ let value: u8 = value.0.into();
+ value.into()
+ }
+ }
+
+ impl From<kernel::error::Error> for BlkError {
+ fn from(_value: kernel::error::Error) -> Self {
+ code::BLK_STS_IOERR
+ }
+ }
+
+ /// A result with a [`BlkError`] error type.
+ pub type BlkResult<T = ()> = Result<T, BlkError>;
+
+ /// Convert a `blk_status_t` to a `BlkResult`.
+ pub fn to_result(status: bindings::blk_status_t) -> BlkResult {
+ if status == bindings::BLK_STS_OK {
+ Ok(())
+ } else {
+ Err(BlkError::from_blk_status(status))
+ }
+ }
+}
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 258b12afdcba3..e656465010d6c 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -162,8 +162,9 @@ pub fn to_errno(self) -> crate::ffi::c_int {
self.0.get()
}
+ /// Convert a generic kernel error to a block layer error.
#[cfg(CONFIG_BLOCK)]
- pub(crate) fn to_blk_status(self) -> bindings::blk_status_t {
+ pub fn to_blk_status(self) -> bindings::blk_status_t {
// SAFETY: `self.0` is a valid error due to its invariant.
unsafe { bindings::errno_to_blk_status(self.0.get()) }
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 38/79] block: rust: require `queue_rq` to return a `BlkResult`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (36 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 37/79] block: rust: introduce `kernel::block::error` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 39/79] block: rust: add `GenDisk::queue_data` Andreas Hindborg
` (40 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Change the return type of `Operations::queue_rq` from `Result` to
`BlkResult`. This ensures that drivers return proper block layer status
codes that can be translated to the appropriate `blk_status_t` value.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 3 ++-
rust/kernel/block/mq.rs | 4 ++--
rust/kernel/block/mq/operations.rs | 7 +++++--
3 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 034ddc06eabf9..55cbdfed25414 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -20,6 +20,7 @@
BadBlocks, //
},
bio::Segment,
+ error::BlkResult,
mq::{
self,
gen_disk::{
@@ -577,7 +578,7 @@ fn queue_rq(
this: Pin<&Self>,
rq: Owned<mq::IdleRequest<Self>>,
_is_last: bool,
- ) -> Result {
+ ) -> BlkResult {
let mut rq = rq.start();
let mut sectors = rq.sectors();
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index a898dda2635e5..02738f52389ba 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -64,7 +64,7 @@
//! ```rust
//! use kernel::{
//! bindings,
-//! block::mq::{self, *},
+//! block::{error::BlkResult, mq::{self, *}},
//! new_mutex,
//! prelude::*,
//! sync::{aref::ARef, Arc, Mutex},
@@ -90,7 +90,7 @@
//! _queue_data: (),
//! rq: Owned<IdleRequest<Self>>,
//! _is_last: bool
-//! ) -> Result {
+//! ) -> BlkResult {
//! rq.start().end_ok();
//! Ok(())
//! }
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index fb75d65f67071..17468a39af60f 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -6,7 +6,10 @@
use crate::{
bindings,
- block::mq::{request::RequestDataWrapper, IdleRequest, Request},
+ block::{
+ error::BlkResult,
+ mq::{request::RequestDataWrapper, IdleRequest, Request},
+ },
error::{from_result, Result},
prelude::*,
sync::{aref::ARef, atomic::ordering, Refcount},
@@ -62,7 +65,7 @@ fn queue_rq(
queue_data: ForeignBorrowed<'_, Self::QueueData>,
rq: Owned<IdleRequest<Self>>,
is_last: bool,
- ) -> Result;
+ ) -> BlkResult;
/// Called by the kernel to indicate that queued requests should be submitted.
fn commit_rqs(
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 39/79] block: rust: add `GenDisk::queue_data`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (37 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 38/79] block: rust: require `queue_rq` to return a `BlkResult` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 40/79] block: rnull: add bandwidth limiting Andreas Hindborg
` (39 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method to borrow the private queue data of the queue a `GenDisk` is
associated with.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/gen_disk.rs | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 8a22767f1b916..fbda2f572e17f 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -246,6 +246,12 @@ pub fn queue(&self) -> &RequestQueue<T> {
// SAFETY: By type invariant, self is a valid gendisk.
unsafe { RequestQueue::from_raw((*self.gendisk).queue) }
}
+
+ /// Get the queue data associated with this [`GenDisk`].
+ pub fn queue_data(&self) -> <T::QueueData as ForeignOwnable>::Borrowed<'_> {
+ // SAFETY: By type invariant, self is a valid gendisk.
+ unsafe { T::QueueData::borrow((*(*self.gendisk).queue).queuedata) }
+ }
}
// SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 40/79] block: rnull: add bandwidth limiting
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (38 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 39/79] block: rust: add `GenDisk::queue_data` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 41/79] block: rnull: add blocking queue mode Andreas Hindborg
` (38 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add bandwidth limiting support to rnull via the `mbps` configfs
attribute. When set to a non-zero value, the driver limits I/O
throughput to the specified rate in megabytes per second.
The implementation uses a token bucket algorithm to enforce the rate
limit, delaying request completion when the limit is exceeded.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 7 ++-
drivers/block/rnull/rnull.rs | 111 +++++++++++++++++++++++++++++++++++-----
2 files changed, 105 insertions(+), 13 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index e365eb06be6de..d369d8b683c61 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -105,6 +105,7 @@ fn make_group(
badblocks_once: 13,
badblocks_partial_io: 14,
cache_size_mib: 15,
+ mbps: 16,
],
};
@@ -136,6 +137,7 @@ fn make_group(
GFP_KERNEL
)?,
cache_size_mib: 0,
+ mbps: 0,
}),
}),
core::iter::empty(),
@@ -200,6 +202,7 @@ struct DeviceConfigInner {
bad_blocks_partial_io: bool,
cache_size_mib: u64,
disk_storage: Arc<DiskStorage>,
+ mbps: u32,
}
#[vtable]
@@ -239,6 +242,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
bad_blocks_once: guard.bad_blocks_once,
bad_blocks_partial_io: guard.bad_blocks_partial_io,
storage: guard.disk_storage.clone(),
+ bandwidth_limit: u64::from(guard.mbps) * 2u64.pow(20),
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -250,7 +254,6 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
-// DiskStorage::new(cache_size_mib << 20, block_size as usize),
configfs_simple_field!(DeviceConfig, 1, block_size, u32, check GenDiskBuilder::validate_block_size);
configfs_simple_bool_field!(DeviceConfig, 2, rotational);
configfs_simple_field!(DeviceConfig, 3, capacity_mib, u64);
@@ -457,3 +460,5 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
Ok(())
})
);
+
+configfs_simple_field!(DeviceConfig, 16, mbps, u32);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 55cbdfed25414..16a4f915e59f4 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -25,7 +25,8 @@
self,
gen_disk::{
self,
- GenDisk, //
+ GenDisk,
+ GenDiskRef, //
},
Operations,
TagSet, //
@@ -37,24 +38,31 @@
Result, //
},
ffi,
+ impl_has_hr_timer,
new_mutex,
new_spinlock,
pr_info,
prelude::*,
+ revocable::Revocable,
str::CString,
sync::{
aref::ARef,
atomic::{
ordering,
Atomic, //
- }, //
+ },
Arc,
+ ArcBorrow,
Mutex,
+ SetOnce,
SpinLock,
- SpinLockGuard,
+ SpinLockGuard, //
},
time::{
hrtimer::{
+ self,
+ ArcHrTimerHandle,
+ HrTimer,
HrTimerCallback,
HrTimerCallbackContext,
HrTimerPointer,
@@ -129,6 +137,10 @@
default: 0,
description: "No IO scheduler",
},
+ mbps: u32 {
+ default: 0,
+ description: "Max bandwidth in MiB/s. 0 means no limit.",
+ },
},
}
@@ -174,6 +186,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
bad_blocks_once: false,
bad_blocks_partial_io: false,
storage: Arc::pin_init(DiskStorage::new(0, block_size as usize), GFP_KERNEL)?,
+ bandwidth_limit: u64::from(*module_parameters::mbps.value()) * 2u64.pow(20),
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -204,6 +217,7 @@ struct NullBlkOptions<'a> {
bad_blocks_once: bool,
bad_blocks_partial_io: bool,
storage: Arc<DiskStorage>,
+ bandwidth_limit: u64,
}
#[pin_data]
@@ -216,9 +230,18 @@ struct NullBlkDevice {
bad_blocks: Arc<BadBlocks>,
bad_blocks_once: bool,
bad_blocks_partial_io: bool,
+ bandwidth_limit: u64,
+ #[pin]
+ bandwidth_timer: HrTimer<Self>,
+ bandwidth_bytes: Atomic<u64>,
+ #[pin]
+ bandwidth_timer_handle: SpinLock<Option<ArcHrTimerHandle<Self>>>,
+ disk: SetOnce<Arc<Revocable<GenDiskRef<Self>>>>,
}
impl NullBlkDevice {
+ const BANDWIDTH_TIMER_INTERVAL: Delta = Delta::from_millis(20);
+
fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
let NullBlkOptions {
name,
@@ -236,6 +259,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
bad_blocks_once,
bad_blocks_partial_io,
storage,
+ bandwidth_limit,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -260,7 +284,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
GFP_KERNEL,
)?;
- let queue_data = Box::try_pin_init(
+ let queue_data = Arc::try_pin_init(
try_pin_init!(Self {
storage,
irq_mode,
@@ -270,6 +294,11 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
bad_blocks,
bad_blocks_once,
bad_blocks_partial_io,
+ bandwidth_limit: bandwidth_limit / 50,
+ bandwidth_timer <- HrTimer::new(),
+ bandwidth_bytes: Atomic::new(0),
+ bandwidth_timer_handle <- new_spinlock!(None),
+ disk: SetOnce::new(),
}),
GFP_KERNEL,
)?;
@@ -286,7 +315,10 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
.max_hw_discard_sectors(ffi::c_uint::MAX >> block::SECTOR_SHIFT);
}
- builder.build(fmt!("{}", name.to_str()?), tagset, queue_data)
+ let disk = builder.build(fmt!("{}", name.to_str()?), tagset, queue_data)?;
+ let queue_data: ArcBorrow<'_, Self> = disk.queue_data();
+ queue_data.disk.populate(disk.get_ref());
+ Ok(disk)
}
fn sheaf_size() -> usize {
@@ -504,6 +536,36 @@ fn end_request(rq: Owned<mq::Request<Self>>) {
}
}
+impl_has_hr_timer! {
+ impl HasHrTimer<Self> for NullBlkDevice {
+ mode: hrtimer::RelativeHardMode<kernel::time::Monotonic>,
+ field: self.bandwidth_timer,
+ }
+}
+
+impl HrTimerCallback for NullBlkDevice {
+ type Pointer<'a> = Arc<Self>;
+
+ fn run(
+ this: ArcBorrow<'_, Self>,
+ mut context: HrTimerCallbackContext<'_, Self>,
+ ) -> HrTimerRestart {
+ if this.bandwidth_bytes.load(ordering::Relaxed) == 0 {
+ return HrTimerRestart::NoRestart;
+ }
+
+ this.disk.as_ref().map(|disk| {
+ disk.try_access()
+ .map(|disk| disk.queue().start_stopped_hw_queues_async())
+ });
+
+ this.bandwidth_bytes.store(0, ordering::Relaxed);
+
+ context.forward_now(Self::BANDWIDTH_TIMER_INTERVAL);
+ HrTimerRestart::Restart
+ }
+}
+
struct HwQueueContext {
page: Option<KBox<disk_storage::NullBlockPage>>,
}
@@ -511,7 +573,7 @@ struct HwQueueContext {
#[pin_data]
struct Pdu {
#[pin]
- timer: kernel::time::hrtimer::HrTimer<Self>,
+ timer: HrTimer<Self>,
error: Atomic<u32>,
}
@@ -560,14 +622,14 @@ fn align_down<T>(value: T, to: T) -> T
#[vtable]
impl Operations for NullBlkDevice {
- type QueueData = Pin<KBox<Self>>;
+ type QueueData = Arc<Self>;
type RequestData = Pdu;
type TagSetData = ();
type HwData = Pin<KBox<SpinLock<HwQueueContext>>>;
fn new_request_data() -> impl PinInit<Self::RequestData> {
pin_init!(Pdu {
- timer <- kernel::time::hrtimer::HrTimer::new(),
+ timer <- HrTimer::new(),
error: Atomic::new(0),
})
}
@@ -575,14 +637,39 @@ fn new_request_data() -> impl PinInit<Self::RequestData> {
#[inline(always)]
fn queue_rq(
hw_data: Pin<&SpinLock<HwQueueContext>>,
- this: Pin<&Self>,
+ this: ArcBorrow<'_, Self>,
rq: Owned<mq::IdleRequest<Self>>,
_is_last: bool,
) -> BlkResult {
- let mut rq = rq.start();
let mut sectors = rq.sectors();
- Self::handle_bad_blocks(this.get_ref(), &mut rq, &mut sectors)?;
+ if this.bandwidth_limit != 0 {
+ if !this.bandwidth_timer.active() {
+ drop(this.bandwidth_timer_handle.lock().take());
+ let arc: Arc<_> = this.into();
+ *this.bandwidth_timer_handle.lock() =
+ Some(arc.start(Self::BANDWIDTH_TIMER_INTERVAL));
+ }
+
+ if this
+ .bandwidth_bytes
+ .fetch_add(u64::from(rq.bytes()), ordering::Relaxed)
+ + u64::from(rq.bytes())
+ > this.bandwidth_limit
+ {
+ rq.queue().stop_hw_queues();
+ if this.bandwidth_bytes.load(ordering::Relaxed) <= this.bandwidth_limit {
+ rq.queue().start_stopped_hw_queues_async();
+ }
+
+ return Err(kernel::block::error::code::BLK_STS_DEV_RESOURCE);
+ }
+ }
+
+ let mut rq = rq.start();
+
+ use core::ops::Deref;
+ Self::handle_bad_blocks(this.deref(), &mut rq, &mut sectors)?;
if this.memory_backed {
if rq.command() == bindings::req_op_REQ_OP_DISCARD {
@@ -604,7 +691,7 @@ fn queue_rq(
Ok(())
}
- fn commit_rqs(_hw_data: Pin<&SpinLock<HwQueueContext>>, _queue_data: Pin<&Self>) {}
+ fn commit_rqs(_hw_data: Pin<&SpinLock<HwQueueContext>>, _queue_data: ArcBorrow<'_, Self>) {}
fn init_hctx(_tagset_data: (), _hctx_idx: u32) -> Result<Self::HwData> {
KBox::pin_init(new_spinlock!(HwQueueContext { page: None }), GFP_KERNEL)
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 41/79] block: rnull: add blocking queue mode
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (39 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 40/79] block: rnull: add bandwidth limiting Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 42/79] block: rnull: add shared tags Andreas Hindborg
` (37 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for blocking queue mode via the `blocking` configfs
attribute. When enabled, the tag set is created with the
`BLK_MQ_F_BLOCKING` flag.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 7 ++++++-
drivers/block/rnull/rnull.rs | 9 ++++++++-
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index d369d8b683c61..640e3de230c0a 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -70,7 +70,7 @@ impl AttributeOperations<0> for Config {
let mut writer = kernel::str::Formatter::new(page);
writer.write_str(
"blocksize,size,rotational,irqmode,completion_nsec,memory_backed\
- submit_queues,use_per_node_hctx\n",
+ submit_queues,use_per_node_hctx,discard,blocking\n",
)?;
Ok(writer.bytes_written())
}
@@ -106,6 +106,7 @@ fn make_group(
badblocks_partial_io: 14,
cache_size_mib: 15,
mbps: 16,
+ blocking: 17,
],
};
@@ -138,6 +139,7 @@ fn make_group(
)?,
cache_size_mib: 0,
mbps: 0,
+ blocking: false,
}),
}),
core::iter::empty(),
@@ -203,6 +205,7 @@ struct DeviceConfigInner {
cache_size_mib: u64,
disk_storage: Arc<DiskStorage>,
mbps: u32,
+ blocking: bool,
}
#[vtable]
@@ -243,6 +246,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
bad_blocks_partial_io: guard.bad_blocks_partial_io,
storage: guard.disk_storage.clone(),
bandwidth_limit: u64::from(guard.mbps) * 2u64.pow(20),
+ blocking: guard.blocking,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -462,3 +466,4 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
);
configfs_simple_field!(DeviceConfig, 16, mbps, u32);
+configfs_simple_bool_field!(DeviceConfig, 17, blocking);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 16a4f915e59f4..cfc00c104d9ca 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -141,6 +141,10 @@
default: 0,
description: "Max bandwidth in MiB/s. 0 means no limit.",
},
+ blocking: u8 {
+ default: 0,
+ description: "Register as a blocking blk-mq driver device",
+ },
},
}
@@ -187,6 +191,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
bad_blocks_partial_io: false,
storage: Arc::pin_init(DiskStorage::new(0, block_size as usize), GFP_KERNEL)?,
bandwidth_limit: u64::from(*module_parameters::mbps.value()) * 2u64.pow(20),
+ blocking: *module_parameters::blocking.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -218,6 +223,7 @@ struct NullBlkOptions<'a> {
bad_blocks_partial_io: bool,
storage: Arc<DiskStorage>,
bandwidth_limit: u64,
+ blocking: bool,
}
#[pin_data]
@@ -260,6 +266,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
bad_blocks_partial_io,
storage,
bandwidth_limit,
+ blocking,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -267,7 +274,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
// TODO: lim.features |= BLK_FEAT_WRITE_CACHE;
// if (dev->fua)
// lim.features |= BLK_FEAT_FUA;
- if memory_backed {
+ if blocking || memory_backed {
flags |= mq::tag_set::Flag::Blocking;
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 42/79] block: rnull: add shared tags
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (40 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 41/79] block: rnull: add blocking queue mode Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 43/79] block: rnull: add queue depth config option Andreas Hindborg
` (36 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for sharing tags between multiple rnull devices. When
enabled via the `shared_tags` configfs attribute, all devices in the
group share a single tag set, reducing memory usage.
This feature requires creating a shared `TagSet` that can be referenced
by multiple devices.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 7 ++++++-
drivers/block/rnull/rnull.rs | 25 +++++++++++++++++++++----
rust/kernel/block/mq/tag_set.rs | 6 ++++++
3 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 640e3de230c0a..d1a70fe030cb2 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -70,7 +70,7 @@ impl AttributeOperations<0> for Config {
let mut writer = kernel::str::Formatter::new(page);
writer.write_str(
"blocksize,size,rotational,irqmode,completion_nsec,memory_backed\
- submit_queues,use_per_node_hctx,discard,blocking\n",
+ submit_queues,use_per_node_hctx,discard,blocking,shared_tags\n",
)?;
Ok(writer.bytes_written())
}
@@ -107,6 +107,7 @@ fn make_group(
cache_size_mib: 15,
mbps: 16,
blocking: 17,
+ shared_tags: 18,
],
};
@@ -140,6 +141,7 @@ fn make_group(
cache_size_mib: 0,
mbps: 0,
blocking: false,
+ shared_tags: false,
}),
}),
core::iter::empty(),
@@ -206,6 +208,7 @@ struct DeviceConfigInner {
disk_storage: Arc<DiskStorage>,
mbps: u32,
blocking: bool,
+ shared_tags: bool,
}
#[vtable]
@@ -247,6 +250,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
storage: guard.disk_storage.clone(),
bandwidth_limit: u64::from(guard.mbps) * 2u64.pow(20),
blocking: guard.blocking,
+ shared_tags: guard.shared_tags,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -467,3 +471,4 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_field!(DeviceConfig, 16, mbps, u32);
configfs_simple_bool_field!(DeviceConfig, 17, blocking);
+configfs_simple_bool_field!(DeviceConfig, 18, shared_tags);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index cfc00c104d9ca..84e75a7042214 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -145,6 +145,10 @@
default: 0,
description: "Register as a blocking blk-mq driver device",
},
+ shared_tags: u8 {
+ default: 0,
+ description: "Share tag set between devices for blk-mq",
+ },
},
}
@@ -192,6 +196,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
storage: Arc::pin_init(DiskStorage::new(0, block_size as usize), GFP_KERNEL)?,
bandwidth_limit: u64::from(*module_parameters::mbps.value()) * 2u64.pow(20),
blocking: *module_parameters::blocking.value() != 0,
+ shared_tags: *module_parameters::shared_tags.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -224,8 +229,11 @@ struct NullBlkOptions<'a> {
storage: Arc<DiskStorage>,
bandwidth_limit: u64,
blocking: bool,
+ shared_tags: bool,
}
+static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
+
#[pin_data]
struct NullBlkDevice {
storage: Arc<DiskStorage>,
@@ -267,6 +275,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
storage,
bandwidth_limit,
blocking,
+ shared_tags,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -286,10 +295,18 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
return Err(code::EINVAL);
}
- let tagset = Arc::pin_init(
- TagSet::new(submit_queues, (), 256, 1, home_node, flags),
- GFP_KERNEL,
- )?;
+ let tagset_ctor = || -> Result<Arc<_>> {
+ Arc::pin_init(
+ TagSet::new(submit_queues, (), 256, 1, home_node, flags),
+ GFP_KERNEL,
+ )
+ };
+
+ let tagset = if shared_tags {
+ SHARED_TAG_SET.as_ref_or_populate_with(tagset_ctor)?.clone()
+ } else {
+ tagset_ctor()?
+ };
let queue_data = Arc::try_pin_init(
try_pin_init!(Self {
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index f18b51e5217fe..600c9c6249123 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -106,3 +106,9 @@ fn drop(self: Pin<&mut Self>) {
unsafe { T::TagSetData::from_foreign(tagset_data) };
}
}
+
+// SAFETY: It is safe to transfer ownership of `TagSet` across thread boundaries.
+unsafe impl<T: Operations> Sync for TagSet<T> {}
+
+// SAFETY: It is safe to share references to `TagSet` across thread boundaries.
+unsafe impl<T: Operations> Send for TagSet<T> {}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 43/79] block: rnull: add queue depth config option
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (41 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 42/79] block: rnull: add shared tags Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 44/79] block: rust: add an abstraction for `bindings::req_op` Andreas Hindborg
` (35 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a configfs attribute to configure the queue depth (number of tags)
for the rnull block device.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 5 +++++
drivers/block/rnull/rnull.rs | 9 ++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index d1a70fe030cb2..90f2ecb454285 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -108,6 +108,7 @@ fn make_group(
mbps: 16,
blocking: 17,
shared_tags: 18,
+ hw_queue_depth: 19
],
};
@@ -142,6 +143,7 @@ fn make_group(
mbps: 0,
blocking: false,
shared_tags: false,
+ hw_queue_depth: 64,
}),
}),
core::iter::empty(),
@@ -209,6 +211,7 @@ struct DeviceConfigInner {
mbps: u32,
blocking: bool,
shared_tags: bool,
+ hw_queue_depth: u32,
}
#[vtable]
@@ -251,6 +254,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
bandwidth_limit: u64::from(guard.mbps) * 2u64.pow(20),
blocking: guard.blocking,
shared_tags: guard.shared_tags,
+ hw_queue_depth: guard.hw_queue_depth,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -472,3 +476,4 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_field!(DeviceConfig, 16, mbps, u32);
configfs_simple_bool_field!(DeviceConfig, 17, blocking);
configfs_simple_bool_field!(DeviceConfig, 18, shared_tags);
+configfs_simple_field!(DeviceConfig, 19, hw_queue_depth, u32);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 84e75a7042214..3fb19836ce6ff 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -149,6 +149,10 @@
default: 0,
description: "Share tag set between devices for blk-mq",
},
+ hw_queue_depth: u32 {
+ default: 64,
+ description: "Queue depth for each hardware queue. Default: 64",
+ },
},
}
@@ -197,6 +201,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
bandwidth_limit: u64::from(*module_parameters::mbps.value()) * 2u64.pow(20),
blocking: *module_parameters::blocking.value() != 0,
shared_tags: *module_parameters::shared_tags.value() != 0,
+ hw_queue_depth: *module_parameters::hw_queue_depth.value(),
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -230,6 +235,7 @@ struct NullBlkOptions<'a> {
bandwidth_limit: u64,
blocking: bool,
shared_tags: bool,
+ hw_queue_depth: u32,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -276,6 +282,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
bandwidth_limit,
blocking,
shared_tags,
+ hw_queue_depth,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -297,7 +304,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
let tagset_ctor = || -> Result<Arc<_>> {
Arc::pin_init(
- TagSet::new(submit_queues, (), 256, 1, home_node, flags),
+ TagSet::new(submit_queues, (), hw_queue_depth, 1, home_node, flags),
GFP_KERNEL,
)
};
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 44/79] block: rust: add an abstraction for `bindings::req_op`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (42 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 43/79] block: rnull: add queue depth config option Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 45/79] block: rust: add a method to set the target sector of a request Andreas Hindborg
` (34 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add the `Command` enum as a Rust abstraction for block request operation
codes. The enum variants correspond to the C `REQ_OP_*` defines and
include read, write, flush, discard, and zone management operations.
Also add a `command()` method to `Request` to retrieve the operation
code.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 6 +--
rust/kernel/block/mq.rs | 1 +
rust/kernel/block/mq/request.rs | 11 +++++-
rust/kernel/block/mq/request/command.rs | 65 +++++++++++++++++++++++++++++++++
4 files changed, 79 insertions(+), 4 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 3fb19836ce6ff..9383b82f9a736 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -508,10 +508,10 @@ fn transfer(
.len()
.min((end_sector - sector) as u32 >> SECTOR_SHIFT);
match command {
- bindings::req_op_REQ_OP_WRITE => {
+ mq::Command::Write => {
self.write(&mut tree_guard, &mut hw_data_guard, sector, segment)?
}
- bindings::req_op_REQ_OP_READ => {
+ mq::Command::Read => {
self.read(&mut tree_guard, &mut hw_data_guard, sector, segment)?
}
_ => (),
@@ -703,7 +703,7 @@ fn queue_rq(
Self::handle_bad_blocks(this.deref(), &mut rq, &mut sectors)?;
if this.memory_backed {
- if rq.command() == bindings::req_op_REQ_OP_DISCARD {
+ if rq.command() == mq::Command::Discard {
this.discard(&hw_data, rq.sector(), sectors)?;
} else {
this.transfer(&hw_data, &mut rq, sectors)?;
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 02738f52389ba..057a5f366be3a 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -131,6 +131,7 @@
pub mod tag_set;
pub use operations::Operations;
+pub use request::Command;
pub use request::IdleRequest;
pub use request::Request;
pub use request::RequestTimerHandle;
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index d6f3ffde1c5c4..4e47419776e0f 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -23,6 +23,9 @@
use crate::block::bio::Bio;
use crate::block::bio::BioIterator;
+mod command;
+pub use command::Command;
+
/// A [`Request`] that a driver has not yet begun to process.
///
/// A driver can convert an `IdleRequest` to a [`Request`] by calling [`IdleRequest::start`].
@@ -89,11 +92,17 @@ fn deref(&self) -> &Self::Target {
impl<T: Operations> RequestInner<T> {
/// Get the command identifier for the request
- pub fn command(&self) -> u32 {
+ fn command_raw(&self) -> u32 {
// SAFETY: By C API contract and type invariant, `cmd_flags` is valid for read
unsafe { (*self.0.get()).cmd_flags & ((1 << bindings::REQ_OP_BITS) - 1) }
}
+ /// Get the command of this request.
+ pub fn command(&self) -> Command {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
+ unsafe { Command::from_raw(self.command_raw()) }
+ }
+
/// Get the target sector for the request.
#[inline(always)]
pub fn sector(&self) -> u64 {
diff --git a/rust/kernel/block/mq/request/command.rs b/rust/kernel/block/mq/request/command.rs
new file mode 100644
index 0000000000000..70a8d67fa35c0
--- /dev/null
+++ b/rust/kernel/block/mq/request/command.rs
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/// Block I/O operation codes.
+///
+/// This is the Rust abstraction for the C [`enum req_op`].
+///
+/// Operations common to the bio and request structures. The kernel uses 8 bits
+/// for encoding the operation, and the remaining 24 bits for flags.
+///
+/// The least significant bit of the operation number indicates the data
+/// transfer direction:
+///
+/// - If the least significant bit is set, transfers are TO the device.
+/// - If the least significant bit is not set, transfers are FROM the device.
+///
+/// If an operation does not transfer data, the least significant bit has no
+/// meaning.
+///
+/// [`enum req_op`]: srctree/include/linux/blk_types.h
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[repr(u32)]
+pub enum Command {
+ /// Read sectors from the device.
+ Read = bindings::req_op_REQ_OP_READ,
+ /// Write sectors to the device.
+ Write = bindings::req_op_REQ_OP_WRITE,
+ /// Flush the volatile write cache.
+ Flush = bindings::req_op_REQ_OP_FLUSH,
+ /// Discard sectors.
+ Discard = bindings::req_op_REQ_OP_DISCARD,
+ /// Securely erase sectors.
+ SecureErase = bindings::req_op_REQ_OP_SECURE_ERASE,
+ /// Write data at the current zone write pointer.
+ ZoneAppend = bindings::req_op_REQ_OP_ZONE_APPEND,
+ /// Write zeroes. This allows to implement zeroing for devices that don't use either discard
+ /// with a predictable zero pattern or WRITE SAME of zeroes.
+ WriteZeroes = bindings::req_op_REQ_OP_WRITE_ZEROES,
+ /// Open a zone.
+ ZoneOpen = bindings::req_op_REQ_OP_ZONE_OPEN,
+ /// Close a zone.
+ ZoneClose = bindings::req_op_REQ_OP_ZONE_CLOSE,
+ /// Transition a zone to full.
+ ZoneFinish = bindings::req_op_REQ_OP_ZONE_FINISH,
+ /// Reset a zone write pointer.
+ ZoneReset = bindings::req_op_REQ_OP_ZONE_RESET,
+ /// Reset all the zones present on the device.
+ ZoneResetAll = bindings::req_op_REQ_OP_ZONE_RESET_ALL,
+ /// Driver private request for data transfer to the driver.
+ DriverIn = bindings::req_op_REQ_OP_DRV_IN,
+ /// Driver private request for data transfer from the driver.
+ DriverOut = bindings::req_op_REQ_OP_DRV_OUT,
+}
+
+impl Command {
+ /// Creates a [`Command`] from a raw `u32` value.
+ ///
+ /// # Safety
+ ///
+ /// The value must be a valid `req_op` operation code.
+ pub unsafe fn from_raw(value: u32) -> Self {
+ // SAFETY: The caller guarantees that the value is a valid operation
+ // code.
+ unsafe { core::mem::transmute(value) }
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 45/79] block: rust: add a method to set the target sector of a request
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (43 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 44/79] block: rust: add an abstraction for `bindings::req_op` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 46/79] block: rust: move gendisk vtable construction to separate function Andreas Hindborg
` (33 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a `block::mq::Request::set_sector` to allow setting the target sector
of a request.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 4e47419776e0f..4e7adb10929f0 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -7,6 +7,7 @@
use crate::{
bindings,
block::mq::Operations,
+ prelude::*,
sync::{
aref::{ARef, RefCounted},
atomic::ordering,
@@ -296,6 +297,13 @@ pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper<T> {
pub fn data_ref(&self) -> &T::RequestData {
&self.wrapper_ref().data
}
+
+ /// Set the target sector for the request.
+ #[inline(always)]
+ pub fn set_sector(self: Pin<&mut Self>, sector: u64) {
+ // SAFETY: By type invariant of `Self`, `self.0` is valid and live.
+ unsafe { (*self.0 .0.get()).__sector = sector }
+ }
}
/// A wrapper around data stored in the private area of the C [`struct request`].
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 46/79] block: rust: move gendisk vtable construction to separate function
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (44 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 45/79] block: rust: add a method to set the target sector of a request Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 47/79] block: rust: add zoned block device support Andreas Hindborg
` (32 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Refactor the `GenDiskBuilder::build` method to move the `gendisk`
vtable construction into a separate helper function. This prepares for
adding zoned block device support which requires conditional vtable
setup.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 5 ++-
rust/kernel/block/mq/gen_disk.rs | 66 ++++++++++++++++++++++------------------
2 files changed, 40 insertions(+), 31 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 90f2ecb454285..5dfe7b48af63b 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -266,7 +266,10 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
-configfs_simple_field!(DeviceConfig, 1, block_size, u32, check GenDiskBuilder::validate_block_size);
+configfs_simple_field!(DeviceConfig, 1,
+ block_size, u32,
+ check GenDiskBuilder::<NullBlkDevice>::validate_block_size
+);
configfs_simple_bool_field!(DeviceConfig, 2, rotational);
configfs_simple_field!(DeviceConfig, 3, capacity_mib, u64);
configfs_simple_field!(DeviceConfig, 4, irq_mode, IRQMode);
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index fbda2f572e17f..eb980079530bd 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -17,20 +17,21 @@
sync::{Arc, UniqueArc},
types::{ForeignOwnable, ScopeGuard},
};
-use core::ptr::NonNull;
+use core::{marker::PhantomData, ptr::NonNull};
/// A builder for [`GenDisk`].
///
/// Use this struct to configure and add new [`GenDisk`] to the VFS.
-pub struct GenDiskBuilder {
+pub struct GenDiskBuilder<T> {
rotational: bool,
logical_block_size: u32,
physical_block_size: u32,
capacity_sectors: u64,
max_hw_discard_sectors: u32,
+ _p: PhantomData<T>,
}
-impl Default for GenDiskBuilder {
+impl<T> Default for GenDiskBuilder<T> {
fn default() -> Self {
Self {
rotational: false,
@@ -38,11 +39,12 @@ fn default() -> Self {
physical_block_size: bindings::PAGE_SIZE as u32,
capacity_sectors: 0,
max_hw_discard_sectors: 0,
+ _p: PhantomData,
}
}
}
-impl GenDiskBuilder {
+impl<T: Operations> GenDiskBuilder<T> {
/// Create a new instance.
pub fn new() -> Self {
Self::default()
@@ -109,7 +111,7 @@ pub fn max_hw_discard_sectors(mut self, max_hw_discard_sectors: u32) -> Self {
}
/// Build a new `GenDisk` and add it to the VFS.
- pub fn build<T: Operations>(
+ pub fn build(
self,
name: fmt::Arguments<'_>,
tagset: Arc<TagSet<T>>,
@@ -141,32 +143,8 @@ pub fn build<T: Operations>(
)
})?;
- const TABLE: bindings::block_device_operations = bindings::block_device_operations {
- submit_bio: None,
- open: None,
- release: None,
- ioctl: None,
- compat_ioctl: None,
- check_events: None,
- unlock_native_capacity: None,
- getgeo: None,
- set_read_only: None,
- swap_slot_free_notify: None,
- report_zones: None,
- devnode: None,
- alternative_gpt_sector: None,
- get_unique_id: None,
- // TODO: Set to THIS_MODULE. Waiting for const_refs_to_static feature to
- // be merged (unstable in rustc 1.78 which is staged for linux 6.10)
- // <https://github.com/rust-lang/rust/issues/119618>
- owner: core::ptr::null_mut(),
- pr_ops: core::ptr::null_mut(),
- free_disk: None,
- poll_bio: None,
- };
-
// SAFETY: `gendisk` is a valid pointer as we initialized it above
- unsafe { (*gendisk).fops = &TABLE };
+ unsafe { (*gendisk).fops = Self::build_vtable() };
let mut writer = NullTerminatedFormatter::new(
// SAFETY: `gendisk` points to a valid and initialized instance. We
@@ -219,6 +197,34 @@ pub fn build<T: Operations>(
Ok(disk.into())
}
+
+ const VTABLE: bindings::block_device_operations = bindings::block_device_operations {
+ submit_bio: None,
+ open: None,
+ release: None,
+ ioctl: None,
+ compat_ioctl: None,
+ check_events: None,
+ unlock_native_capacity: None,
+ getgeo: None,
+ set_read_only: None,
+ swap_slot_free_notify: None,
+ report_zones: None,
+ devnode: None,
+ alternative_gpt_sector: None,
+ get_unique_id: None,
+ // TODO: Set to THIS_MODULE. Waiting for const_refs_to_static feature to
+ // be merged (unstable in rustc 1.78 which is staged for linux 6.10)
+ // <https://github.com/rust-lang/rust/issues/119618>
+ owner: core::ptr::null_mut(),
+ pr_ops: core::ptr::null_mut(),
+ free_disk: None,
+ poll_bio: None,
+ };
+
+ pub(crate) const fn build_vtable() -> &'static bindings::block_device_operations {
+ &Self::VTABLE
+ }
}
/// A generic block device.
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 47/79] block: rust: add zoned block device support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (45 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 46/79] block: rust: move gendisk vtable construction to separate function Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 48/79] block: rnull: add zoned storage support Andreas Hindborg
` (31 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for zoned block devices to the Rust block layer bindings.
This includes the `report_zones` callback in `Operations` and methods
in `GenDiskBuilder` to configure zoned device parameters.
Drivers can mark a disk as zoned and configure the zone size and
maximum zone append size. The `report_zones` callback is invoked by
the block layer to query zone information.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/bindings/bindings_helper.h | 1 +
rust/kernel/block/mq/gen_disk.rs | 96 +++++++++++++++++++++++++++++++++-----
rust/kernel/block/mq/operations.rs | 60 ++++++++++++++++++++++--
3 files changed, 142 insertions(+), 15 deletions(-)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 76b58c3fd1ff1..05133a78ecf95 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -133,6 +133,7 @@ const blk_status_t RUST_CONST_HELPER_BLK_STS_ZONE_ACTIVE_RESOURCE = BLK_STS_ZONE
const blk_status_t RUST_CONST_HELPER_BLK_STS_OFFLINE = BLK_STS_OFFLINE;
const blk_status_t RUST_CONST_HELPER_BLK_STS_DURATION_LIMIT = BLK_STS_DURATION_LIMIT;
const blk_status_t RUST_CONST_HELPER_BLK_STS_INVAL = BLK_STS_INVAL;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ZONED = BLK_FEAT_ZONED;
const fop_flags_t RUST_CONST_HELPER_FOP_UNSIGNED_OFFSET = FOP_UNSIGNED_OFFSET;
const xa_mark_t RUST_CONST_HELPER_XA_PRESENT = XA_PRESENT;
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index eb980079530bd..a6f113ea4bea4 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -7,7 +7,7 @@
use crate::{
bindings,
- block::mq::{Operations, RequestQueue, TagSet},
+ block::mq::{operations::OperationsVTable, Operations, RequestQueue, TagSet},
error::{self, from_err_ptr, Result},
fmt::{self, Write},
prelude::*,
@@ -28,6 +28,12 @@ pub struct GenDiskBuilder<T> {
physical_block_size: u32,
capacity_sectors: u64,
max_hw_discard_sectors: u32,
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ zoned: bool,
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ zone_size_sectors: u32,
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ zone_append_max_sectors: u32,
_p: PhantomData<T>,
}
@@ -39,6 +45,12 @@ fn default() -> Self {
physical_block_size: bindings::PAGE_SIZE as u32,
capacity_sectors: 0,
max_hw_discard_sectors: 0,
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ zoned: false,
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ zone_size_sectors: 0,
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ zone_append_max_sectors: 0,
_p: PhantomData,
}
}
@@ -110,6 +122,27 @@ pub fn max_hw_discard_sectors(mut self, max_hw_discard_sectors: u32) -> Self {
self
}
+ /// Mark this device as a zoned block device.
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ pub fn zoned(mut self, enable: bool) -> Self {
+ self.zoned = enable;
+ self
+ }
+
+ /// Set the zone size of this block device.
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ pub fn zone_size(mut self, sectors: u32) -> Self {
+ self.zone_size_sectors = sectors;
+ self
+ }
+
+ /// Set the max zone append size for this block device.
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ pub fn zone_append_max(mut self, sectors: u32) -> Self {
+ self.zone_append_max_sectors = sectors;
+ self
+ }
+
/// Build a new `GenDisk` and add it to the VFS.
pub fn build(
self,
@@ -130,7 +163,18 @@ pub fn build(
lim.physical_block_size = self.physical_block_size;
lim.max_hw_discard_sectors = self.max_hw_discard_sectors;
if self.rotational {
- lim.features = bindings::BLK_FEAT_ROTATIONAL;
+ lim.features |= bindings::BLK_FEAT_ROTATIONAL;
+ }
+
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ if self.zoned {
+ if !T::HAS_REPORT_ZONES {
+ return Err(error::code::EINVAL);
+ }
+
+ lim.features |= bindings::BLK_FEAT_ZONED;
+ lim.chunk_sectors = self.zone_size_sectors;
+ lim.max_hw_zone_append_sectors = self.zone_append_max_sectors;
}
// SAFETY: `tagset.raw_tag_set()` points to a valid and initialized tag set
@@ -160,14 +204,6 @@ pub fn build(
// operation, so we will not race.
unsafe { bindings::set_capacity(gendisk, self.capacity_sectors) };
- crate::error::to_result(
- // SAFETY: `gendisk` points to a valid and initialized instance of
- // `struct gendisk`.
- unsafe {
- bindings::device_add_disk(core::ptr::null_mut(), gendisk, core::ptr::null_mut())
- },
- )?;
-
recover_data.dismiss();
// INVARIANT: `gendisk` was initialized above.
@@ -195,7 +231,27 @@ pub fn build(
GFP_KERNEL,
)?;
- Ok(disk.into())
+ let disk: Arc<_> = disk.into();
+
+ // SAFETY: `disk.gendisk` is valid for write as we initialized it above. We have exclusive
+ // access.
+ unsafe { (*disk.gendisk).private_data = Arc::as_ptr(&disk).cast_mut().cast() };
+
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ if self.zoned {
+ // SAFETY: `disk.gendisk` is valid as we initialized it above. We have exclusive access.
+ unsafe { bindings::blk_revalidate_disk_zones(gendisk) };
+ }
+
+ crate::error::to_result(
+ // SAFETY: `gendisk` points to a valid and initialized instance of
+ // `struct gendisk`.
+ unsafe {
+ bindings::device_add_disk(core::ptr::null_mut(), gendisk, core::ptr::null_mut())
+ },
+ )?;
+
+ Ok(disk)
}
const VTABLE: bindings::block_device_operations = bindings::block_device_operations {
@@ -209,7 +265,11 @@ pub fn build(
getgeo: None,
set_read_only: None,
swap_slot_free_notify: None,
- report_zones: None,
+ report_zones: if T::HAS_REPORT_ZONES {
+ Some(OperationsVTable::<T>::report_zones_callback)
+ } else {
+ None
+ },
devnode: None,
alternative_gpt_sector: None,
get_unique_id: None,
@@ -295,6 +355,18 @@ fn drop(&mut self) {
/// `self.0` is valid for use as a reference.
pub struct GenDiskRef<T: Operations>(NonNull<GenDisk<T>>);
+impl<T: Operations> GenDiskRef<T> {
+ /// Create a `GenDiskRef` from a pointer to a `GenDisk`.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be valid for use as a `GenDisk` reference for the lifetime of the returned
+ /// `GenDiskRef`.
+ pub(crate) unsafe fn from_ptr(ptr: NonNull<GenDisk<T>>) -> GenDiskRef<T> {
+ Self(ptr)
+ }
+}
+
// SAFETY: It is safe to transfer ownership of `GenDiskRef` across thread boundaries.
unsafe impl<T: Operations> Send for GenDiskRef<T> {}
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 17468a39af60f..3f84ebadec86b 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -8,14 +8,14 @@
bindings,
block::{
error::BlkResult,
- mq::{request::RequestDataWrapper, IdleRequest, Request},
+ mq::{gen_disk::GenDiskRef, request::RequestDataWrapper, IdleRequest, Request},
},
- error::{from_result, Result},
+ error::{from_result, to_result, Result},
prelude::*,
sync::{aref::ARef, atomic::ordering, Refcount},
types::{ForeignOwnable, Owned},
};
-use core::marker::PhantomData;
+use core::{marker::PhantomData, ptr::NonNull};
use pin_init::PinInit;
type ForeignBorrowed<'a, T> = <T as ForeignOwnable>::Borrowed<'a>;
@@ -87,6 +87,20 @@ fn init_hctx(
fn poll(_hw_data: ForeignBorrowed<'_, Self::HwData>) -> bool {
build_error!(crate::error::VTABLE_DEFAULT_ERROR)
}
+
+ /// Called by the kernel to get a zone report from the driver.
+ ///
+ /// The driver must call `callback` once for each zone on `disk` and populate the first argument
+ /// with a zone descriptor and the second argument when the zone index.
+ // TODO: We cannot gate this on CONFIG_BLK_DEV_ZONED due to limitations of the `vtable` macro.
+ fn report_zones(
+ _disk: &GenDiskRef<Self>,
+ _sector: u64,
+ _nr_zones: u32,
+ _callback: impl Fn(&bindings::blk_zone, u32) -> Result,
+ ) -> Result<u32> {
+ Err(ENOTSUPP)
+ }
}
/// A vtable for blk-mq to interact with a block device driver.
@@ -340,6 +354,46 @@ impl<T: Operations> OperationsVTable<T> {
unsafe { core::ptr::drop_in_place(pdu) };
}
+ /// This function is a callback hook for the C kernel. A pointer to this function is
+ /// installed in the `blk_mq_ops` vtable for the driver.
+ ///
+ /// # Safety
+ ///
+ /// - This function may only be called by blk-mq C infrastructure.
+ /// - `disk_ptr` must be a pointer to a gendisk initialized by `GenDisk::build`.
+ pub(crate) unsafe extern "C" fn report_zones_callback(
+ disk_ptr: *mut bindings::gendisk,
+ sector: u64,
+ nr_zones: u32,
+ args: *mut bindings::blk_report_zones_args,
+ ) -> i32 {
+ // SAFETY: As `disk_ptr` is a gendisk initialized by `GenDisk::build`, `private_data` is not
+ // null.
+ let disk_ref_ptr = unsafe { NonNull::new_unchecked((*disk_ptr).private_data.cast()) };
+
+ // SAFETY: `disk_ptr.private_data` is a pointer to the `GenDisk` owner of `disk_ptr` that we
+ // installed when we initialized `disk_ptr`. It is valid for use as a reference for the
+ // duration of this call.
+ let disk = unsafe { GenDiskRef::from_ptr(disk_ref_ptr) };
+
+ from_result(|| {
+ T::report_zones(&disk, sector, nr_zones, |zone, idx| -> Result {
+ to_result(
+ // SAFETY: `disk_ptr` is valid by function safety requirements.
+ unsafe {
+ bindings::disk_report_zone(
+ disk_ptr,
+ core::ptr::from_ref(zone).cast_mut(),
+ idx,
+ args,
+ )
+ },
+ )
+ })
+ .and_then(|v: u32| -> Result<_> { Ok(v.try_into()?) })
+ })
+ }
+
const VTABLE: bindings::blk_mq_ops = bindings::blk_mq_ops {
queue_rq: Some(Self::queue_rq_callback),
queue_rqs: None,
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 48/79] block: rnull: add zoned storage support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (46 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 47/79] block: rust: add zoned block device support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 49/79] block: rust: add `map_queues` support Andreas Hindborg
` (30 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add zoned block device emulation to rnull. When enabled via the `zoned`
configfs attribute, the driver emulates a zoned storage device with
configurable zone size and zone count.
The implementation supports zone management operations including zone
reset, zone open, zone close, and zone finish. Zone write pointer
tracking is maintained for sequential write required zones.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 54 ++-
drivers/block/rnull/disk_storage.rs | 34 +-
drivers/block/rnull/disk_storage/page.rs | 4 +-
drivers/block/rnull/rnull.rs | 233 +++++++----
drivers/block/rnull/util.rs | 65 +++
drivers/block/rnull/zoned.rs | 661 +++++++++++++++++++++++++++++++
6 files changed, 951 insertions(+), 100 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 5dfe7b48af63b..0873d696f80f6 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -70,7 +70,8 @@ impl AttributeOperations<0> for Config {
let mut writer = kernel::str::Formatter::new(page);
writer.write_str(
"blocksize,size,rotational,irqmode,completion_nsec,memory_backed\
- submit_queues,use_per_node_hctx,discard,blocking,shared_tags\n",
+ submit_queues,use_per_node_hctx,discard,blocking,shared_tags,\
+ zoned,zone_size,zone_capacity\n",
)?;
Ok(writer.bytes_written())
}
@@ -108,7 +109,14 @@ fn make_group(
mbps: 16,
blocking: 17,
shared_tags: 18,
- hw_queue_depth: 19
+ hw_queue_depth: 19,
+ zoned: 20,
+ zone_size: 21,
+ zone_capacity: 22,
+ zone_nr_conv: 23,
+ zone_max_open: 24,
+ zone_max_active: 25,
+ zone_append_max_sectors: 26,
],
};
@@ -135,15 +143,19 @@ fn make_group(
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
bad_blocks_once: false,
bad_blocks_partial_io: false,
- disk_storage: Arc::pin_init(
- DiskStorage::new(0, block_size as usize),
- GFP_KERNEL
- )?,
+ disk_storage: Arc::pin_init(DiskStorage::new(0, block_size), GFP_KERNEL)?,
cache_size_mib: 0,
mbps: 0,
blocking: false,
shared_tags: false,
hw_queue_depth: 64,
+ zoned: false,
+ zone_size_mib: 256,
+ zone_capacity_mib: 0,
+ zone_nr_conv: 0,
+ zone_max_open: 0,
+ zone_max_active: 0,
+ zone_append_max_sectors: u32::MAX,
}),
}),
core::iter::empty(),
@@ -212,6 +224,13 @@ struct DeviceConfigInner {
blocking: bool,
shared_tags: bool,
hw_queue_depth: u32,
+ zoned: bool,
+ zone_size_mib: u32,
+ zone_capacity_mib: u32,
+ zone_nr_conv: u32,
+ zone_max_open: u32,
+ zone_max_active: u32,
+ zone_append_max_sectors: u32,
}
#[vtable]
@@ -237,9 +256,9 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
if !guard.powered && power_op {
guard.disk = Some(NullBlkDevice::new(crate::NullBlkOptions {
name: &guard.name,
- block_size: guard.block_size,
+ block_size_bytes: guard.block_size,
rotational: guard.rotational,
- capacity_mib: guard.capacity_mib,
+ device_capacity_mib: guard.capacity_mib,
irq_mode: guard.irq_mode,
completion_time: guard.completion_time,
memory_backed: guard.memory_backed,
@@ -255,6 +274,13 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
blocking: guard.blocking,
shared_tags: guard.shared_tags,
hw_queue_depth: guard.hw_queue_depth,
+ zoned: guard.zoned,
+ zone_size_mib: guard.zone_size_mib,
+ zone_capacity_mib: guard.zone_capacity_mib,
+ zone_nr_conv: guard.zone_nr_conv,
+ zone_max_open: guard.zone_max_open,
+ zone_max_active: guard.zone_max_active,
+ zone_append_max_sectors: guard.zone_append_max_sectors,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -467,10 +493,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
let text = core::str::from_utf8(page)?.trim();
let value = text.parse::<u64>().map_err(|_| EINVAL)?;
let mut guard = this.data.lock();
- guard.disk_storage = Arc::pin_init(
- DiskStorage::new(value, guard.block_size as usize),
- GFP_KERNEL
- )?;
+ guard.disk_storage = Arc::pin_init(DiskStorage::new(value, guard.block_size), GFP_KERNEL)?;
guard.cache_size_mib = value;
Ok(())
})
@@ -480,3 +503,10 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_bool_field!(DeviceConfig, 17, blocking);
configfs_simple_bool_field!(DeviceConfig, 18, shared_tags);
configfs_simple_field!(DeviceConfig, 19, hw_queue_depth, u32);
+configfs_simple_bool_field!(DeviceConfig, 20, zoned);
+configfs_simple_field!(DeviceConfig, 21, zone_size_mib, u32);
+configfs_simple_field!(DeviceConfig, 22, zone_capacity_mib, u32);
+configfs_simple_field!(DeviceConfig, 23, zone_nr_conv, u32);
+configfs_simple_field!(DeviceConfig, 24, zone_max_open, u32);
+configfs_simple_field!(DeviceConfig, 25, zone_max_active, u32);
+configfs_simple_field!(DeviceConfig, 26, zone_append_max_sectors, u32);
diff --git a/drivers/block/rnull/disk_storage.rs b/drivers/block/rnull/disk_storage.rs
index 8a8a90e1cf0bd..ce3e83671709a 100644
--- a/drivers/block/rnull/disk_storage.rs
+++ b/drivers/block/rnull/disk_storage.rs
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
use super::HwQueueContext;
+use crate::util::*;
use core::pin::Pin;
use kernel::{
block,
@@ -9,8 +10,12 @@
page::PAGE_SIZE,
prelude::*,
sync::{
- atomic::{ordering, Atomic},
- SpinLock, SpinLockGuard,
+ atomic::{
+ ordering,
+ Atomic, //
+ },
+ SpinLock,
+ SpinLockGuard, //
},
uapi::PAGE_SECTORS,
xarray::{
@@ -31,11 +36,11 @@ pub(crate) struct DiskStorage {
cache_size: u64,
cache_size_used: Atomic<u64>,
next_flush_sector: Atomic<u64>,
- block_size: usize,
+ block_size: u32,
}
impl DiskStorage {
- pub(crate) fn new(cache_size: u64, block_size: usize) -> impl PinInit<Self, Error> {
+ pub(crate) fn new(cache_size: u64, block_size: u32) -> impl PinInit<Self, Error> {
try_pin_init!( Self {
// TODO: Get rid of the box
// https://git.kernel.org/pub/scm/linux/kernel/git/boqun/linux.git/commit/?h=locking&id=a5d84cafb3e253a11d2e078902c5b090be2f4227
@@ -59,6 +64,27 @@ pub(crate) fn access<'a, 'b, 'c>(
pub(crate) fn lock(&self) -> SpinLockGuard<'_, Pin<KBox<TreeContainer>>> {
self.trees.lock()
}
+
+ pub(crate) fn discard(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ mut sector: u64,
+ sectors: u32,
+ ) {
+ let mut tree_guard = self.lock();
+ let mut hw_data_guard = hw_data.lock();
+
+ let mut access = self.access(&mut tree_guard, &mut hw_data_guard, None);
+
+ let mut remaining_bytes = sectors_to_bytes(sectors);
+
+ while remaining_bytes > 0 {
+ access.free_sector(sector);
+ let processed = remaining_bytes.min(self.block_size);
+ sector += Into::<u64>::into(bytes_to_sectors(processed));
+ remaining_bytes -= processed;
+ }
+ }
}
pub(crate) struct DiskStorageAccess<'a, 'b, 'c> {
diff --git a/drivers/block/rnull/disk_storage/page.rs b/drivers/block/rnull/disk_storage/page.rs
index c2e18502cbdda..a34fe0762724d 100644
--- a/drivers/block/rnull/disk_storage/page.rs
+++ b/drivers/block/rnull/disk_storage/page.rs
@@ -19,11 +19,11 @@
pub(crate) struct NullBlockPage {
page: Owned<SafePage>,
status: u64,
- block_size: usize,
+ block_size: u32,
}
impl NullBlockPage {
- pub(crate) fn new(block_size: usize) -> Result<KBox<Self>> {
+ pub(crate) fn new(block_size: u32) -> Result<KBox<Self>> {
Ok(KBox::new(
Self {
page: SafePage::alloc_page(GFP_NOIO | __GFP_ZERO)?,
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 9383b82f9a736..48b2bd598304c 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -2,8 +2,13 @@
//! This is a Rust implementation of the C null block driver.
+#![recursion_limit = "256"]
+
mod configfs;
mod disk_storage;
+mod util;
+#[cfg(CONFIG_BLK_DEV_ZONED)]
+mod zoned;
use configfs::IRQMode;
use disk_storage::{
@@ -77,6 +82,7 @@
xarray::XArraySheaf, //
};
use pin_init::PinInit;
+use util::*;
module! {
type: NullBlkModule,
@@ -153,6 +159,35 @@
default: 64,
description: "Queue depth for each hardware queue. Default: 64",
},
+ zoned: u8 {
+ default: 0,
+ description: "Make device as a host-managed zoned block device. Default: 0",
+ },
+ zone_size: u32 {
+ default: 256,
+ description:
+ "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256",
+ },
+ zone_capacity: u32 {
+ default: 0,
+ description: "Zone capacity in MB when block device is zoned. Can be less than or equal to zone size. Default: Zone size",
+ },
+ zone_nr_conv: u32 {
+ default: 0,
+ description: "Number of conventional zones when block device is zoned. Default: 0",
+ },
+ zone_max_open: u32 {
+ default: 0,
+ description: "Maximum number of open zones when block device is zoned. Default: 0 (no limit)",
+ },
+ zone_max_active: u32 {
+ default: 0,
+ description: "Maximum number of active zones when block device is zoned. Default: 0 (no limit)",
+ },
+ zone_append_max_sectors: u32 {
+ default: 0,
+ description: "Maximum size of a zone append command (in 512B sectors). Specify 0 for no zone append.",
+ },
},
}
@@ -184,9 +219,9 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
let block_size = *module_parameters::bs.value();
let disk = NullBlkDevice::new(NullBlkOptions {
name: &name,
- block_size,
+ block_size_bytes: block_size,
rotational: *module_parameters::rotational.value() != 0,
- capacity_mib: *module_parameters::gb.value() * 1024,
+ device_capacity_mib: *module_parameters::gb.value() * 1024,
irq_mode: (*module_parameters::irqmode.value()).try_into()?,
completion_time: Delta::from_nanos(completion_time),
memory_backed: *module_parameters::memory_backed.value() != 0,
@@ -197,11 +232,18 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
bad_blocks: Arc::pin_init(BadBlocks::new(false), GFP_KERNEL)?,
bad_blocks_once: false,
bad_blocks_partial_io: false,
- storage: Arc::pin_init(DiskStorage::new(0, block_size as usize), GFP_KERNEL)?,
+ storage: Arc::pin_init(DiskStorage::new(0, block_size), GFP_KERNEL)?,
bandwidth_limit: u64::from(*module_parameters::mbps.value()) * 2u64.pow(20),
blocking: *module_parameters::blocking.value() != 0,
shared_tags: *module_parameters::shared_tags.value() != 0,
hw_queue_depth: *module_parameters::hw_queue_depth.value(),
+ zoned: *module_parameters::zoned.value() != 0,
+ zone_size_mib: *module_parameters::zone_size.value(),
+ zone_capacity_mib: *module_parameters::zone_capacity.value(),
+ zone_nr_conv: *module_parameters::zone_nr_conv.value(),
+ zone_max_open: *module_parameters::zone_max_open.value(),
+ zone_max_active: *module_parameters::zone_max_active.value(),
+ zone_append_max_sectors: *module_parameters::zone_append_max_sectors.value(),
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -218,9 +260,9 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
struct NullBlkOptions<'a> {
name: &'a CStr,
- block_size: u32,
+ block_size_bytes: u32,
rotational: bool,
- capacity_mib: u64,
+ device_capacity_mib: u64,
irq_mode: IRQMode,
completion_time: Delta,
memory_backed: bool,
@@ -236,6 +278,19 @@ struct NullBlkOptions<'a> {
blocking: bool,
shared_tags: bool,
hw_queue_depth: u32,
+ zoned: bool,
+ #[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
+ zone_size_mib: u32,
+ #[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
+ zone_capacity_mib: u32,
+ #[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
+ zone_nr_conv: u32,
+ #[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
+ zone_max_open: u32,
+ #[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
+ zone_max_active: u32,
+ #[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
+ zone_append_max_sectors: u32,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -246,7 +301,7 @@ struct NullBlkDevice {
irq_mode: IRQMode,
completion_time: Delta,
memory_backed: bool,
- block_size: usize,
+ block_size_bytes: u32,
bad_blocks: Arc<BadBlocks>,
bad_blocks_once: bool,
bad_blocks_partial_io: bool,
@@ -257,6 +312,9 @@ struct NullBlkDevice {
#[pin]
bandwidth_timer_handle: SpinLock<Option<ArcHrTimerHandle<Self>>>,
disk: SetOnce<Arc<Revocable<GenDiskRef<Self>>>>,
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ #[pin]
+ zoned: zoned::ZoneOptions,
}
impl NullBlkDevice {
@@ -265,9 +323,9 @@ impl NullBlkDevice {
fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
let NullBlkOptions {
name,
- block_size,
+ block_size_bytes,
rotational,
- capacity_mib,
+ device_capacity_mib,
irq_mode,
completion_time,
memory_backed,
@@ -283,6 +341,13 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
blocking,
shared_tags,
hw_queue_depth,
+ zoned,
+ zone_size_mib,
+ zone_capacity_mib,
+ zone_nr_conv,
+ zone_max_open,
+ zone_max_active,
+ zone_append_max_sectors,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -315,13 +380,15 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
tagset_ctor()?
};
+ let device_capacity_sectors = mib_to_sectors(device_capacity_mib);
+
let queue_data = Arc::try_pin_init(
try_pin_init!(Self {
storage,
irq_mode,
completion_time,
memory_backed,
- block_size: block_size as usize,
+ block_size_bytes,
bad_blocks,
bad_blocks_once,
bad_blocks_partial_io,
@@ -330,17 +397,42 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
bandwidth_bytes: Atomic::new(0),
bandwidth_timer_handle <- new_spinlock!(None),
disk: SetOnce::new(),
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ zoned <- zoned::ZoneOptions::new(zoned::ZoneOptionsArgs {
+ enable: zoned,
+ device_capacity_mib,
+ block_size_bytes: *block_size_bytes,
+ zone_size_mib,
+ zone_capacity_mib,
+ zone_nr_conv,
+ zone_max_open,
+ zone_max_active,
+ zone_append_max_sectors,
+ })?,
}),
GFP_KERNEL,
)?;
let mut builder = gen_disk::GenDiskBuilder::new()
- .capacity_sectors(capacity_mib << (20 - block::SECTOR_SHIFT))
- .logical_block_size(block_size)?
- .physical_block_size(block_size)?
+ .capacity_sectors(device_capacity_sectors)
+ .logical_block_size(block_size_bytes)?
+ .physical_block_size(block_size_bytes)?
.rotational(rotational);
- if memory_backed && discard {
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ {
+ builder = builder
+ .zoned(zoned)
+ .zone_size(queue_data.zoned.size_sectors)
+ .zone_append_max(zone_append_max_sectors);
+ }
+
+ if !cfg!(CONFIG_BLK_DEV_ZONED) && zoned {
+ return Err(ENOTSUPP);
+ }
+
+ // TODO: Warn on invalid discard configuration (zoned, memory)
+ if memory_backed && discard && !zoned {
builder = builder
// Max IO size is u32::MAX bytes
.max_hw_discard_sectors(ffi::c_uint::MAX >> block::SECTOR_SHIFT);
@@ -364,13 +456,12 @@ fn sheaf_size() -> usize {
fn preload<'b, 'c>(
tree_guard: &'b mut SpinLockGuard<'c, Pin<KBox<TreeContainer>>>,
hw_data_guard: &'b mut SpinLockGuard<'c, HwQueueContext>,
- block_size: usize,
+ block_size_bytes: u32,
) -> Result {
if hw_data_guard.page.is_none() {
- hw_data_guard.page =
- Some(tree_guard.do_unlocked(|| {
- hw_data_guard.do_unlocked(|| NullBlockPage::new(block_size))
- })?);
+ hw_data_guard.page = Some(tree_guard.do_unlocked(|| {
+ hw_data_guard.do_unlocked(|| NullBlockPage::new(block_size_bytes))
+ })?);
}
Ok(())
@@ -387,7 +478,7 @@ fn write<'a, 'b, 'c>(
let mut sheaf: Option<XArraySheaf<'_>> = None;
while !segment.is_empty() {
- Self::preload(tree_guard, hw_data_guard, self.block_size)?;
+ Self::preload(tree_guard, hw_data_guard, self.block_size_bytes)?;
match &mut sheaf {
Some(sheaf) => {
@@ -453,48 +544,23 @@ fn read<'a, 'b, 'c>(
sector += segment.copy_from_page(page.page(), page_offset as usize) as u64
>> block::SECTOR_SHIFT;
}
- None => sector += segment.zero_page() as u64 >> block::SECTOR_SHIFT,
+ None => sector += bytes_to_sectors(segment.zero_page() as u64),
}
}
Ok(())
}
- fn discard(
- &self,
- hw_data: &Pin<&SpinLock<HwQueueContext>>,
- mut sector: u64,
- sectors: u32,
- ) -> Result {
- let mut tree_guard = self.storage.lock();
- let mut hw_data_guard = hw_data.lock();
-
- let mut access = self
- .storage
- .access(&mut tree_guard, &mut hw_data_guard, None);
-
- let mut remaining_bytes = (sectors as usize) << SECTOR_SHIFT;
-
- while remaining_bytes > 0 {
- access.free_sector(sector);
- let processed = remaining_bytes.min(self.block_size);
- sector += (processed >> SECTOR_SHIFT) as u64;
- remaining_bytes -= processed;
- }
-
- Ok(())
- }
-
#[inline(never)]
fn transfer(
&self,
hw_data: &Pin<&SpinLock<HwQueueContext>>,
rq: &mut Owned<mq::Request<Self>>,
+ command: mq::Command,
sectors: u32,
) -> Result {
let mut sector = rq.sector();
let end_sector = sector + <u32 as Into<u64>>::into(sectors);
- let command = rq.command();
// TODO: Use `PerCpu` to get rid of this lock
let mut hw_data_guard = hw_data.lock();
@@ -527,6 +593,26 @@ fn transfer(
Ok(())
}
+ fn handle_regular_command(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ rq: &mut Owned<mq::Request<Self>>,
+ ) -> Result {
+ let mut sectors = rq.sectors();
+
+ self.handle_bad_blocks(rq, &mut sectors)?;
+
+ if self.memory_backed {
+ if rq.command() == mq::Command::Discard {
+ self.storage.discard(hw_data, rq.sector(), sectors);
+ } else {
+ self.transfer(hw_data, rq, rq.command(), sectors)?;
+ }
+ }
+
+ Ok(())
+ }
+
fn handle_bad_blocks(&self, rq: &mut Owned<mq::Request<Self>>, sectors: &mut u32) -> Result {
if self.bad_blocks.enabled() {
let start = rq.sector();
@@ -542,7 +628,7 @@ fn handle_bad_blocks(&self, rq: &mut Owned<mq::Request<Self>>, sectors: &mut u32
}
if self.bad_blocks_partial_io {
- let block_size_sectors = (self.block_size >> SECTOR_SHIFT) as u64;
+ let block_size_sectors = u64::from(bytes_to_sectors(self.block_size_bytes));
range.start = align_down(range.start, block_size_sectors);
if start < range.start {
*sectors = (range.start - start) as u32;
@@ -627,30 +713,6 @@ impl HasHrTimer<Self> for Pdu {
}
}
-fn is_power_of_two<T>(value: T) -> bool
-where
- T: core::ops::Sub<T, Output = T>,
- T: core::ops::BitAnd<Output = T>,
- T: core::cmp::PartialOrd<T>,
- T: Copy,
- T: From<u8>,
-{
- (value > 0u8.into()) && (value & (value - 1u8.into())) == 0u8.into()
-}
-
-fn align_down<T>(value: T, to: T) -> T
-where
- T: core::ops::Sub<T, Output = T>,
- T: core::ops::Not<Output = T>,
- T: core::ops::BitAnd<Output = T>,
- T: core::cmp::PartialOrd<T>,
- T: Copy,
- T: From<u8>,
-{
- debug_assert!(is_power_of_two(to));
- value & !(to - 1u8.into())
-}
-
#[vtable]
impl Operations for NullBlkDevice {
type QueueData = Arc<Self>;
@@ -672,8 +734,6 @@ fn queue_rq(
rq: Owned<mq::IdleRequest<Self>>,
_is_last: bool,
) -> BlkResult {
- let mut sectors = rq.sectors();
-
if this.bandwidth_limit != 0 {
if !this.bandwidth_timer.active() {
drop(this.bandwidth_timer_handle.lock().take());
@@ -699,17 +759,16 @@ fn queue_rq(
let mut rq = rq.start();
- use core::ops::Deref;
- Self::handle_bad_blocks(this.deref(), &mut rq, &mut sectors)?;
-
- if this.memory_backed {
- if rq.command() == mq::Command::Discard {
- this.discard(&hw_data, rq.sector(), sectors)?;
- } else {
- this.transfer(&hw_data, &mut rq, sectors)?;
- }
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ if this.zoned.enabled {
+ this.handle_zoned_command(&hw_data, &mut rq)?;
+ } else {
+ this.handle_regular_command(&hw_data, &mut rq)?;
}
+ #[cfg(not(CONFIG_BLK_DEV_ZONED))]
+ this.handle_regular_command(&hw_data, &mut rq)?;
+
match this.irq_mode {
IRQMode::None => Self::end_request(rq),
IRQMode::Soft => mq::Request::complete(rq.into()),
@@ -735,4 +794,14 @@ fn complete(rq: ARef<mq::Request<Self>>) {
.expect("Failed to complete request"),
)
}
+
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ fn report_zones(
+ disk: &GenDiskRef<Self>,
+ sector: u64,
+ nr_zones: u32,
+ callback: impl Fn(&bindings::blk_zone, u32) -> Result,
+ ) -> Result<u32> {
+ Self::report_zones_internal(disk, sector, nr_zones, callback)
+ }
}
diff --git a/drivers/block/rnull/util.rs b/drivers/block/rnull/util.rs
new file mode 100644
index 0000000000000..044926c8e2840
--- /dev/null
+++ b/drivers/block/rnull/util.rs
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Return true if `value` is a power of two.
+pub(crate) fn is_power_of_two<T>(value: T) -> bool
+where
+ T: core::ops::Sub<T, Output = T>,
+ T: core::ops::BitAnd<Output = T>,
+ T: core::cmp::PartialOrd<T>,
+ T: Copy,
+ T: From<u8>,
+{
+ (value > 0u8.into()) && (value & (value - 1u8.into())) == 0u8.into()
+}
+
+// Round `value` down to the next multiple of `to`, which must be a power of
+// two.
+pub(crate) fn align_down<T>(value: T, to: T) -> T
+where
+ T: core::ops::Sub<T, Output = T>,
+ T: core::ops::Not<Output = T>,
+ T: core::ops::BitAnd<Output = T>,
+ T: core::cmp::PartialOrd<T>,
+ T: Copy,
+ T: From<u8>,
+{
+ debug_assert!(is_power_of_two(to));
+ value & !(to - 1u8.into())
+}
+
+// Round `value` up to the next multiple of `to`, which must be a power of two.
+#[cfg(CONFIG_BLK_DEV_ZONED)]
+pub(crate) fn align_up<T>(value: T, to: T) -> T
+where
+ T: core::ops::Sub<T, Output = T>,
+ T: core::ops::Add<T, Output = T>,
+ T: core::ops::BitAnd<Output = T>,
+ T: core::ops::BitOr<Output = T>,
+ T: core::cmp::PartialOrd<T>,
+ T: Copy,
+ T: From<u8>,
+{
+ debug_assert!(is_power_of_two(to));
+ ((value - 1u8.into()) | (to - 1u8.into())) + 1u8.into()
+}
+
+pub(crate) fn mib_to_sectors<T>(mib: T) -> T
+where
+ T: core::ops::Shl<u32, Output = T>,
+{
+ mib << (20 - kernel::block::SECTOR_SHIFT)
+}
+
+pub(crate) fn sectors_to_bytes<T>(sectors: T) -> T
+where
+ T: core::ops::Shl<u32, Output = T>,
+{
+ sectors << kernel::block::SECTOR_SHIFT
+}
+
+pub(crate) fn bytes_to_sectors<T>(bytes: T) -> T
+where
+ T: core::ops::Shl<u32, Output = T>,
+{
+ bytes << kernel::block::SECTOR_SHIFT
+}
diff --git a/drivers/block/rnull/zoned.rs b/drivers/block/rnull/zoned.rs
new file mode 100644
index 0000000000000..0f15f4cc4e5c3
--- /dev/null
+++ b/drivers/block/rnull/zoned.rs
@@ -0,0 +1,661 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use crate::{
+ util::*,
+ HwQueueContext, //
+};
+use kernel::{
+ bindings,
+ block::mq::{
+ self,
+ gen_disk::GenDiskRef, //
+ },
+ new_mutex,
+ new_spinlock,
+ prelude::*,
+ sync::Mutex,
+ sync::SpinLock,
+ types::Owned, //
+};
+
+pub(crate) struct ZoneOptionsArgs {
+ pub(crate) enable: bool,
+ pub(crate) device_capacity_mib: u64,
+ pub(crate) block_size_bytes: u32,
+ pub(crate) zone_size_mib: u32,
+ pub(crate) zone_capacity_mib: u32,
+ pub(crate) zone_nr_conv: u32,
+ pub(crate) zone_max_open: u32,
+ pub(crate) zone_max_active: u32,
+ pub(crate) zone_append_max_sectors: u32,
+}
+
+#[pin_data]
+pub(crate) struct ZoneOptions {
+ pub(crate) enabled: bool,
+ zones: Pin<KBox<[Mutex<ZoneDescriptor>]>>,
+ conventional_count: u32,
+ pub(crate) size_sectors: u32,
+ append_max_sectors: u32,
+ max_open: u32,
+ max_active: u32,
+ #[pin]
+ accounting: SpinLock<ZoneAccounting>,
+}
+
+impl ZoneOptions {
+ pub(crate) fn new(args: ZoneOptionsArgs) -> Result<impl PinInit<Self, Error>> {
+ let ZoneOptionsArgs {
+ enable,
+ device_capacity_mib,
+ block_size_bytes,
+ zone_size_mib,
+ zone_capacity_mib,
+ mut zone_nr_conv,
+ mut zone_max_open,
+ mut zone_max_active,
+ zone_append_max_sectors,
+ } = args;
+
+ if !is_power_of_two(zone_size_mib) {
+ return Err(EINVAL);
+ }
+
+ if zone_capacity_mib > zone_size_mib {
+ return Err(EINVAL);
+ }
+
+ let zone_size_sectors = mib_to_sectors(zone_size_mib);
+ let device_capacity_sectors = mib_to_sectors(device_capacity_mib);
+ let zone_capacity_sectors = mib_to_sectors(zone_capacity_mib);
+ let zone_count: u32 = (align_up(device_capacity_sectors, zone_size_sectors.into())
+ >> zone_size_sectors.ilog2())
+ .try_into()?;
+
+ if zone_nr_conv >= zone_count {
+ zone_nr_conv = zone_count - 1;
+ pr_info!("changed the number of conventional zones to {zone_nr_conv}\n");
+ }
+
+ let zone_append_max_sectors =
+ align_down(zone_append_max_sectors, bytes_to_sectors(block_size_bytes))
+ .min(zone_capacity_sectors);
+
+ let seq_zone_count = zone_count - zone_nr_conv;
+
+ if zone_max_active >= seq_zone_count {
+ zone_max_active = 0;
+ pr_info!("zone_max_active limit disabled, limit >= zone count\n");
+ }
+
+ if zone_max_active != 0 && zone_max_open > zone_max_active {
+ zone_max_open = zone_max_active;
+ pr_info!("changed the maximum number of open zones to {zone_max_open}\n");
+ } else if zone_max_open >= seq_zone_count {
+ zone_max_open = 0;
+ pr_info!("zone_max_open limit disabled, limit >= zone count\n");
+ }
+
+ Ok(try_pin_init!(Self {
+ enabled: enable,
+ zones: init_zone_descriptors(
+ zone_size_sectors,
+ zone_capacity_sectors,
+ zone_count,
+ zone_nr_conv,
+ )?,
+ size_sectors: zone_size_sectors,
+ append_max_sectors: zone_append_max_sectors,
+ max_open: zone_max_open,
+ max_active: zone_max_active,
+ accounting <- new_spinlock!(ZoneAccounting {
+ implicit_open: 0,
+ explicit_open: 0,
+ closed: 0,
+ start_zone: zone_nr_conv,
+ }),
+ conventional_count: zone_nr_conv,
+ }))
+ }
+}
+
+struct ZoneAccounting {
+ implicit_open: u32,
+ explicit_open: u32,
+ closed: u32,
+ start_zone: u32,
+}
+
+pub(crate) fn init_zone_descriptors(
+ zone_size_sectors: u32,
+ zone_capacity_sectors: u32,
+ zone_count: u32,
+ zone_nr_conv: u32,
+) -> Result<Pin<KBox<[Mutex<ZoneDescriptor>]>>> {
+ let zone_capacity_sectors = if zone_capacity_sectors == 0 {
+ zone_size_sectors
+ } else {
+ zone_capacity_sectors
+ };
+
+ KBox::pin_slice(
+ |i| {
+ let sector = i as u64 * Into::<u64>::into(zone_size_sectors);
+ new_mutex!(
+ if i < zone_nr_conv.try_into().expect("Fewer than 2^32 zones") {
+ ZoneDescriptor {
+ start_sector: sector,
+ size_sectors: zone_size_sectors,
+ capacity_sectors: zone_size_sectors,
+ kind: ZoneType::Conventional,
+ write_pointer: sector + Into::<u64>::into(zone_size_sectors),
+ condition: ZoneCondition::NoWritePointer,
+ }
+ } else {
+ ZoneDescriptor {
+ start_sector: sector,
+ size_sectors: zone_size_sectors,
+ capacity_sectors: zone_capacity_sectors,
+ kind: ZoneType::SequentialWriteRequired,
+ write_pointer: sector,
+ condition: ZoneCondition::Empty,
+ }
+ }
+ )
+ },
+ zone_count as usize,
+ GFP_KERNEL,
+ )
+}
+
+impl super::NullBlkDevice {
+ pub(crate) fn handle_zoned_command(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ rq: &mut Owned<mq::Request<Self>>,
+ ) -> Result {
+ use mq::Command::*;
+ match rq.command() {
+ ZoneAppend | Write => self.zoned_write(hw_data, rq)?,
+ ZoneReset | ZoneResetAll | ZoneOpen | ZoneClose | ZoneFinish => {
+ self.zone_management(hw_data, rq)?
+ }
+ _ => self.zoned_read(hw_data, rq)?,
+ }
+
+ Ok(())
+ }
+
+ fn zone_management(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ rq: &mut Owned<mq::Request<Self>>,
+ ) -> Result {
+ if rq.command() == mq::Command::ZoneResetAll {
+ for zone in self.zoned.zones_iter() {
+ let mut zone = zone.lock();
+ use ZoneCondition::*;
+ match zone.condition {
+ Empty | ReadOnly | Offline => continue,
+ _ => self.zoned.reset_zone(&self.storage, hw_data, &mut zone)?,
+ }
+ }
+
+ return Ok(());
+ }
+
+ let zone = self.zoned.zone(rq.sector())?;
+ let mut zone = zone.lock();
+
+ if zone.condition == ZoneCondition::ReadOnly || zone.condition == ZoneCondition::Offline {
+ return Err(EIO);
+ }
+
+ use mq::Command::*;
+ match rq.command() {
+ ZoneOpen => self.zoned.open_zone(&mut zone, rq.sector()),
+ ZoneClose => self.zoned.close_zone(&mut zone),
+ ZoneReset => self.zoned.reset_zone(&self.storage, hw_data, &mut zone),
+ ZoneFinish => self.zoned.finish_zone(&mut zone, rq.sector()),
+ _ => Err(EIO),
+ }
+ }
+
+ fn zoned_read(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ rq: &mut Owned<mq::Request<Self>>,
+ ) -> Result {
+ let zone = self.zoned.zone(rq.sector())?;
+ let zone = zone.lock();
+ if zone.condition == ZoneCondition::Offline {
+ return Err(EINVAL);
+ }
+
+ zone.check_bounds_read(rq.sector(), rq.sectors())?;
+
+ self.handle_regular_command(hw_data, rq)
+ }
+
+ fn zoned_write(
+ &self,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ rq: &mut Owned<mq::Request<Self>>,
+ ) -> Result {
+ let zone = self.zoned.zone(rq.sector())?;
+ let mut zone = zone.lock();
+ let append: bool = rq.command() == mq::Command::ZoneAppend;
+
+ if zone.kind == ZoneType::Conventional {
+ if append {
+ return Err(EINVAL);
+ }
+
+ // NOTE: C driver does not check bounds on write.
+ zone.check_bounds_write(rq.sector(), rq.sectors())?;
+
+ let mut sectors = rq.sectors();
+ self.handle_bad_blocks(rq, &mut sectors)?;
+ return self.transfer(hw_data, rq, rq.command(), sectors);
+ }
+
+ // Check zoned write fits within zone
+ if zone.write_pointer + Into::<u64>::into(rq.sectors())
+ > zone.start_sector + Into::<u64>::into(zone.capacity_sectors)
+ {
+ return Err(EINVAL);
+ }
+
+ if append {
+ if self.zoned.append_max_sectors == 0 {
+ return Err(EINVAL);
+ }
+ rq.get_pin_mut().set_sector(zone.write_pointer);
+ }
+
+ // Check write pointer alignment
+ if !append && rq.sector() != zone.write_pointer {
+ return Err(EINVAL);
+ }
+
+ if zone.condition == ZoneCondition::Closed || zone.condition == ZoneCondition::Empty {
+ if self.zoned.use_accounting() {
+ let mut accounting = self.zoned.accounting.lock();
+ self.zoned
+ .check_zone_resources(&mut accounting, &mut zone, rq.sector())?;
+
+ if zone.condition == ZoneCondition::Closed {
+ accounting.closed -= 1;
+ accounting.implicit_open += 1;
+ } else if zone.condition == ZoneCondition::Empty {
+ accounting.implicit_open += 1;
+ }
+ }
+
+ zone.condition = ZoneCondition::ImplicitOpen;
+ }
+
+ let mut sectors = rq.sectors();
+ self.handle_bad_blocks(rq, &mut sectors)?;
+
+ if self.memory_backed {
+ self.transfer(hw_data, rq, mq::Command::Write, sectors)?;
+ }
+
+ zone.write_pointer += Into::<u64>::into(sectors);
+ if zone.write_pointer == zone.start_sector + Into::<u64>::into(zone.capacity_sectors) {
+ if self.zoned.use_accounting() {
+ let mut accounting = self.zoned.accounting.lock();
+
+ if zone.condition == ZoneCondition::ExplicitOpen {
+ accounting.explicit_open -= 1;
+ } else if zone.condition == ZoneCondition::ImplicitOpen {
+ accounting.implicit_open -= 1;
+ }
+ }
+
+ zone.condition = ZoneCondition::Full;
+ }
+
+ Ok(())
+ }
+
+ pub(crate) fn report_zones_internal(
+ disk: &GenDiskRef<Self>,
+ sector: u64,
+ nr_zones: u32,
+ callback: impl Fn(&bindings::blk_zone, u32) -> Result,
+ ) -> Result<u32> {
+ let device = disk.queue_data();
+ let first_zone = sector >> device.zoned.size_sectors.ilog2();
+
+ let mut count = 0;
+
+ for (i, zone) in device
+ .zoned
+ .zones
+ .split_at(first_zone as usize)
+ .1
+ .iter()
+ .take(nr_zones as usize)
+ .enumerate()
+ {
+ let zone = zone.lock();
+ let descriptor = bindings::blk_zone {
+ start: zone.start_sector,
+ len: zone.size_sectors.into(),
+ wp: zone.write_pointer,
+ capacity: zone.capacity_sectors.into(),
+ type_: zone.kind as u8,
+ cond: zone.condition as u8,
+ ..bindings::blk_zone::zeroed()
+ };
+ drop(zone);
+ callback(&descriptor, i as u32)?;
+
+ count += 1;
+ }
+
+ Ok(count)
+ }
+}
+
+impl ZoneOptions {
+ fn zone_no(&self, sector: u64) -> usize {
+ (sector >> self.size_sectors.ilog2()) as usize
+ }
+
+ fn zone(&self, sector: u64) -> Result<&Mutex<ZoneDescriptor>> {
+ self.zones.get(self.zone_no(sector)).ok_or(EINVAL)
+ }
+
+ fn zones_iter(&self) -> impl Iterator<Item = &Mutex<ZoneDescriptor>> {
+ self.zones.iter()
+ }
+
+ fn use_accounting(&self) -> bool {
+ self.max_active != 0 || self.max_open != 0
+ }
+
+ fn try_close_implicit_open_zone(&self, accounting: &mut ZoneAccounting, sector: u64) -> Result {
+ let skip = self.zone_no(sector) as u32;
+
+ let it = Iterator::chain(
+ self.zones[(accounting.start_zone as usize)..]
+ .iter()
+ .enumerate()
+ .map(|(i, z)| (i + accounting.start_zone as usize, z)),
+ self.zones[(self.conventional_count as usize)..(accounting.start_zone as usize)]
+ .iter()
+ .enumerate()
+ .map(|(i, z)| (i + self.conventional_count as usize, z)),
+ )
+ .filter(|(i, _)| *i != skip as usize);
+
+ for (index, zone) in it {
+ let mut zone = zone.lock();
+ if zone.condition == ZoneCondition::ImplicitOpen {
+ accounting.implicit_open -= 1;
+
+ let index_u32: u32 = index.try_into()?;
+ let next_zone: u32 = index_u32 + 1;
+ accounting.start_zone = if next_zone == self.zones.len().try_into()? {
+ self.conventional_count
+ } else {
+ next_zone
+ };
+
+ if zone.write_pointer == zone.start_sector {
+ zone.condition = ZoneCondition::Empty;
+ } else {
+ zone.condition = ZoneCondition::Closed;
+ accounting.closed += 1;
+ }
+ return Ok(());
+ }
+ }
+
+ Err(EINVAL)
+ }
+
+ fn open_zone(&self, zone: &mut ZoneDescriptor, sector: u64) -> Result {
+ if zone.kind == ZoneType::Conventional {
+ return Err(EINVAL);
+ }
+
+ use ZoneCondition::*;
+ match zone.condition {
+ ExplicitOpen => return Ok(()),
+ Empty | ImplicitOpen | Closed => (),
+ _ => return Err(EIO),
+ }
+
+ if self.use_accounting() {
+ let mut accounting = self.accounting.lock();
+ match zone.condition {
+ Empty => {
+ self.check_zone_resources(&mut accounting, zone, sector)?;
+ }
+ ImplicitOpen => {
+ accounting.implicit_open -= 1;
+ }
+ Closed => {
+ self.check_zone_resources(&mut accounting, zone, sector)?;
+ accounting.closed -= 1;
+ }
+ _ => (),
+ }
+
+ accounting.explicit_open += 1;
+ }
+
+ zone.condition = ExplicitOpen;
+ Ok(())
+ }
+
+ fn check_zone_resources(
+ &self,
+ accounting: &mut ZoneAccounting,
+ zone: &mut ZoneDescriptor,
+ sector: u64,
+ ) -> Result {
+ match zone.condition {
+ ZoneCondition::Empty => {
+ self.check_active_zones(accounting)?;
+ self.check_open_zones(accounting, sector)
+ }
+ ZoneCondition::Closed => self.check_open_zones(accounting, sector),
+ _ => Err(EIO),
+ }
+ }
+
+ fn check_open_zones(&self, accounting: &mut ZoneAccounting, sector: u64) -> Result {
+ if self.max_open == 0 {
+ return Ok(());
+ }
+
+ if self.max_open > accounting.explicit_open + accounting.implicit_open {
+ return Ok(());
+ }
+
+ if accounting.implicit_open > 0 {
+ self.check_active_zones(accounting)?;
+ return self.try_close_implicit_open_zone(accounting, sector);
+ }
+
+ Err(EBUSY)
+ }
+
+ fn check_active_zones(&self, accounting: &mut ZoneAccounting) -> Result {
+ if self.max_active == 0 {
+ return Ok(());
+ }
+
+ if self.max_active > accounting.implicit_open + accounting.explicit_open + accounting.closed
+ {
+ return Ok(());
+ }
+
+ Err(EBUSY)
+ }
+
+ fn close_zone(&self, zone: &mut ZoneDescriptor) -> Result {
+ if zone.kind == ZoneType::Conventional {
+ return Err(EINVAL);
+ }
+
+ use ZoneCondition::*;
+ match zone.condition {
+ Closed => return Ok(()),
+ ImplicitOpen | ExplicitOpen => (),
+ _ => return Err(EIO),
+ }
+
+ if self.use_accounting() {
+ let mut accounting = self.accounting.lock();
+ match zone.condition {
+ ImplicitOpen => accounting.implicit_open -= 1,
+ ExplicitOpen => accounting.explicit_open -= 1,
+ _ => (),
+ }
+
+ if zone.write_pointer > zone.start_sector {
+ accounting.closed += 1;
+ }
+ }
+
+ if zone.write_pointer == zone.start_sector {
+ zone.condition = Empty;
+ } else {
+ zone.condition = Closed;
+ }
+
+ Ok(())
+ }
+
+ fn finish_zone(&self, zone: &mut ZoneDescriptor, sector: u64) -> Result {
+ if zone.kind == ZoneType::Conventional {
+ return Err(EINVAL);
+ }
+
+ if self.use_accounting() {
+ let mut accounting = self.accounting.lock();
+
+ use ZoneCondition::*;
+ match zone.condition {
+ Full => return Ok(()),
+ Empty => {
+ self.check_zone_resources(&mut accounting, zone, sector)?;
+ }
+ ImplicitOpen => accounting.implicit_open -= 1,
+ ExplicitOpen => accounting.explicit_open -= 1,
+ Closed => {
+ self.check_zone_resources(&mut accounting, zone, sector)?;
+ accounting.closed -= 1;
+ }
+ _ => return Err(EIO),
+ }
+ }
+
+ zone.condition = ZoneCondition::Full;
+ zone.write_pointer = zone.start_sector + Into::<u64>::into(zone.size_sectors);
+
+ Ok(())
+ }
+
+ fn reset_zone(
+ &self,
+ storage: &crate::disk_storage::DiskStorage,
+ hw_data: &Pin<&SpinLock<HwQueueContext>>,
+ zone: &mut ZoneDescriptor,
+ ) -> Result {
+ if zone.kind == ZoneType::Conventional {
+ return Err(EINVAL);
+ }
+
+ if self.use_accounting() {
+ let mut accounting = self.accounting.lock();
+
+ use ZoneCondition::*;
+ match zone.condition {
+ ImplicitOpen => accounting.implicit_open -= 1,
+ ExplicitOpen => accounting.explicit_open -= 1,
+ Closed => accounting.closed -= 1,
+ Empty | Full => (),
+ _ => return Err(EIO),
+ }
+ }
+
+ zone.condition = ZoneCondition::Empty;
+ zone.write_pointer = zone.start_sector;
+
+ storage.discard(hw_data, zone.start_sector, zone.size_sectors);
+
+ Ok(())
+ }
+}
+
+pub(crate) struct ZoneDescriptor {
+ start_sector: u64,
+ size_sectors: u32,
+ kind: ZoneType,
+ capacity_sectors: u32,
+ write_pointer: u64,
+ condition: ZoneCondition,
+}
+
+impl ZoneDescriptor {
+ fn check_bounds_write(&self, sector: u64, sectors: u32) -> Result {
+ if sector + Into::<u64>::into(sectors)
+ > self.start_sector + Into::<u64>::into(self.capacity_sectors)
+ {
+ Err(EIO)
+ } else {
+ Ok(())
+ }
+ }
+
+ fn check_bounds_read(&self, sector: u64, sectors: u32) -> Result {
+ if sector + Into::<u64>::into(sectors) > self.write_pointer {
+ Err(EIO)
+ } else {
+ Ok(())
+ }
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[repr(u32)]
+enum ZoneType {
+ Conventional = bindings::blk_zone_type_BLK_ZONE_TYPE_CONVENTIONAL,
+ SequentialWriteRequired = bindings::blk_zone_type_BLK_ZONE_TYPE_SEQWRITE_REQ,
+ #[expect(dead_code)]
+ SequentialWritePreferred = bindings::blk_zone_type_BLK_ZONE_TYPE_SEQWRITE_PREF,
+}
+
+impl ZoneType {
+ #[expect(dead_code)]
+ fn as_raw(self) -> u32 {
+ self as u32
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[repr(u32)]
+enum ZoneCondition {
+ NoWritePointer = bindings::blk_zone_cond_BLK_ZONE_COND_NOT_WP,
+ Empty = bindings::blk_zone_cond_BLK_ZONE_COND_EMPTY,
+ ImplicitOpen = bindings::blk_zone_cond_BLK_ZONE_COND_IMP_OPEN,
+ ExplicitOpen = bindings::blk_zone_cond_BLK_ZONE_COND_EXP_OPEN,
+ Closed = bindings::blk_zone_cond_BLK_ZONE_COND_CLOSED,
+ Full = bindings::blk_zone_cond_BLK_ZONE_COND_FULL,
+ ReadOnly = bindings::blk_zone_cond_BLK_ZONE_COND_READONLY,
+ Offline = bindings::blk_zone_cond_BLK_ZONE_COND_OFFLINE,
+}
+
+impl ZoneCondition {
+ #[expect(dead_code)]
+ fn as_raw(self) -> u32 {
+ self as u32
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 49/79] block: rust: add `map_queues` support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (47 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 48/79] block: rnull: add zoned storage support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 50/79] block: rust: add an abstraction for `struct blk_mq_queue_map` Andreas Hindborg
` (29 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for the `map_queues` callback to the Rust block layer
bindings. This callback allows drivers to customize the mapping between
CPUs and hardware queues.
The callback receives a mutable reference to the `TagSet`, and drivers
can use the `TagSet::update_maps` method to configure the mappings for
each queue type.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/operations.rs | 28 ++++++++++++++++++++++++++--
rust/kernel/block/mq/tag_set.rs | 13 +++++++++++++
2 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 3f84ebadec86b..017fad010d174 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -8,7 +8,7 @@
bindings,
block::{
error::BlkResult,
- mq::{gen_disk::GenDiskRef, request::RequestDataWrapper, IdleRequest, Request},
+ mq::{gen_disk::GenDiskRef, request::RequestDataWrapper, IdleRequest, Request, TagSet},
},
error::{from_result, to_result, Result},
prelude::*,
@@ -101,6 +101,11 @@ fn report_zones(
) -> Result<u32> {
Err(ENOTSUPP)
}
+
+ /// Called by the kernel to map submission queues to CPU cores.
+ fn map_queues(_tag_set: &TagSet<Self>) {
+ build_error!(crate::error::VTABLE_DEFAULT_ERROR)
+ }
}
/// A vtable for blk-mq to interact with a block device driver.
@@ -394,6 +399,21 @@ impl<T: Operations> OperationsVTable<T> {
})
}
+ /// This function is called by the C kernel. A pointer to this function is
+ /// installed in the `blk_mq_ops` vtable for the driver.
+ ///
+ /// # Safety
+ ///
+ /// This function may only be called by blk-mq C infrastructure. `tag_set`
+ /// must be a pointer to a valid and initialized `TagSet<T>`. The pointee
+ /// must be valid for use as a reference at least the duration of this call.
+ unsafe extern "C" fn map_queues_callback(tag_set: *mut bindings::blk_mq_tag_set) {
+ // SAFETY: The safety requirements of this function satiesfies the
+ // requirements of `TagSet::from_ptr`.
+ let tag_set = unsafe { TagSet::from_ptr(tag_set) };
+ T::map_queues(tag_set);
+ }
+
const VTABLE: bindings::blk_mq_ops = bindings::blk_mq_ops {
queue_rq: Some(Self::queue_rq_callback),
queue_rqs: None,
@@ -415,7 +435,11 @@ impl<T: Operations> OperationsVTable<T> {
exit_request: Some(Self::exit_request_callback),
cleanup_rq: None,
busy: None,
- map_queues: None,
+ map_queues: if T::HAS_MAP_QUEUES {
+ Some(Self::map_queues_callback)
+ } else {
+ None
+ },
#[cfg(CONFIG_BLK_DEBUG_FS)]
show_rq: None,
};
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index 600c9c6249123..330ff28c91507 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -89,6 +89,19 @@ pub fn new(
pub(crate) fn raw_tag_set(&self) -> *mut bindings::blk_mq_tag_set {
self.inner.get()
}
+
+ /// Create a `TagSet<T>` from a raw pointer.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be a pointer to a valid and initialized `TagSet<T>`. There
+ /// may be no other mutable references to the tag set. The pointee must be
+ /// live and valid at least for the duration of the returned lifetime `'a`.
+ pub(crate) unsafe fn from_ptr<'a>(ptr: *mut bindings::blk_mq_tag_set) -> &'a Self {
+ // SAFETY: By the safety requirements of this function, `ptr` is valid
+ // for use as a reference for the duration of `'a`.
+ unsafe { &*(ptr.cast::<Self>()) }
+ }
}
#[pinned_drop]
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 50/79] block: rust: add an abstraction for `struct blk_mq_queue_map`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (48 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 49/79] block: rust: add `map_queues` support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 51/79] block: rust: add polled completion support Andreas Hindborg
` (28 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add the `QueueMap` and `QueueType` types as Rust abstractions for CPU
to hardware queue mappings. The `QueueMap` type wraps `struct
blk_mq_queue_map` and provides methods to set up the mapping between
CPUs and hardware queues.
`QueueType` represents the different queue types: default, read, and
poll queues.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq.rs | 1 +
rust/kernel/block/mq/operations.rs | 10 ++--
rust/kernel/block/mq/tag_set.rs | 96 ++++++++++++++++++++++++++++++++++++++
3 files changed, 102 insertions(+), 5 deletions(-)
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 057a5f366be3a..cd0bfbcbf317a 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -136,4 +136,5 @@
pub use request::Request;
pub use request::RequestTimerHandle;
pub use request_queue::RequestQueue;
+pub use tag_set::QueueType;
pub use tag_set::TagSet;
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 017fad010d174..28dd4b28d203f 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -102,8 +102,8 @@ fn report_zones(
Err(ENOTSUPP)
}
- /// Called by the kernel to map submission queues to CPU cores.
- fn map_queues(_tag_set: &TagSet<Self>) {
+ /// Called by the kernel to map hardware queues to CPU cores.
+ fn map_queues(_tag_set: Pin<&mut TagSet<Self>>) {
build_error!(crate::error::VTABLE_DEFAULT_ERROR)
}
}
@@ -408,9 +408,9 @@ impl<T: Operations> OperationsVTable<T> {
/// must be a pointer to a valid and initialized `TagSet<T>`. The pointee
/// must be valid for use as a reference at least the duration of this call.
unsafe extern "C" fn map_queues_callback(tag_set: *mut bindings::blk_mq_tag_set) {
- // SAFETY: The safety requirements of this function satiesfies the
- // requirements of `TagSet::from_ptr`.
- let tag_set = unsafe { TagSet::from_ptr(tag_set) };
+ // SAFETY: By C API contract `tag_set` is the tag set registered with the `GenDisk` created
+ // by `GenDiskBuilder`.
+ let tag_set = unsafe { TagSet::from_ptr_mut(tag_set) };
T::map_queues(tag_set);
}
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index 330ff28c91507..e6edc5bc39312 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -97,11 +97,46 @@ pub(crate) fn raw_tag_set(&self) -> *mut bindings::blk_mq_tag_set {
/// `ptr` must be a pointer to a valid and initialized `TagSet<T>`. There
/// may be no other mutable references to the tag set. The pointee must be
/// live and valid at least for the duration of the returned lifetime `'a`.
+ #[expect(dead_code)]
pub(crate) unsafe fn from_ptr<'a>(ptr: *mut bindings::blk_mq_tag_set) -> &'a Self {
// SAFETY: By the safety requirements of this function, `ptr` is valid
// for use as a reference for the duration of `'a`.
unsafe { &*(ptr.cast::<Self>()) }
}
+
+ /// Create a `TagSet<T>` from a raw pointer.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must be a pointer to a valid and initialized `TagSet<T>`. There
+ /// may be no other mutable references to the tag set. The pointee must be
+ /// live and valid at least for the duration of the returned lifetime `'a`.
+ pub(crate) unsafe fn from_ptr_mut<'a>(ptr: *mut bindings::blk_mq_tag_set) -> Pin<&'a mut Self> {
+ // SAFETY: By function safety requirements, `ptr` is valid for use as a mutable reference.
+ let mref = unsafe { &mut *(ptr.cast::<Self>()) };
+
+ // SAFETY: We never move out of `mref`.
+ unsafe { Pin::new_unchecked(mref) }
+ }
+
+ /// Helper function to invoke a closure each hardware queue type supported.
+ ///
+ /// This function invokes `cb` for each variant of [`QueueType`] that this [`TagSet`] supports.
+ /// This is helpful for setting up CPU to hardware queue maps in the [`Operations::map_queues`]
+ /// callback.
+ pub fn update_maps(self: Pin<&mut Self>, mut cb: impl FnMut(QueueMap)) -> Result {
+ // SAFETY: By type invariant, `self.inner` is valid.
+ let nr_maps = unsafe { (*self.inner.get()).nr_maps };
+ for i in 0..nr_maps {
+ cb(QueueMap {
+ // SAFETY: By type invariant, `self.inner` is valid.
+ map: unsafe { &raw mut (*self.inner.get()).map[i as usize] },
+ kind: i.try_into()?,
+ });
+ }
+
+ Ok(())
+ }
}
#[pinned_drop]
@@ -125,3 +160,64 @@ unsafe impl<T: Operations> Sync for TagSet<T> {}
// SAFETY: It is safe to share references to `TagSet` across thread boundaries.
unsafe impl<T: Operations> Send for TagSet<T> {}
+
+/// A [`TagSet`] CPU to hardware queue mapping.
+///
+/// # Invariants
+///
+/// - `self.map` points to a valid `blk_mq_queue_map`
+pub struct QueueMap {
+ map: *mut bindings::blk_mq_queue_map,
+ kind: QueueType,
+}
+
+impl QueueMap {
+ /// Set the number of queues for this mapping kind.
+ pub fn set_queue_count(&mut self, nr_queues: u32) {
+ // SAFETY: By type invariant, `self.map` is valid.
+ unsafe { (*self.map).nr_queues = nr_queues }
+ }
+
+ /// First hardware queue to map this queue kind onto. Used by the PCIe NVMe driver to map each
+ /// hardware queue type ([`QueueType`]) onto a distinct set of hardware queues.
+ pub fn set_offset(&mut self, offset: u32) {
+ // SAFETY: By type invariant, `self.map` is valid.
+ unsafe { (*self.map).queue_offset = offset }
+ }
+
+ /// Effectuate the mapping described by [`Self`].
+ pub fn map_queues(&self) {
+ // SAFETY: By type invariant, `self.map` is valid.
+ unsafe { bindings::blk_mq_map_queues(self.map) }
+ }
+
+ /// Return the kind of this queue mapping.
+ pub fn kind(&self) -> QueueType {
+ self.kind
+ }
+}
+
+/// Type of hardware queue.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[repr(u32)]
+pub enum QueueType {
+ /// All I/O not otherwise accounted for.
+ Default = bindings::hctx_type_HCTX_TYPE_DEFAULT,
+ /// Just for READ I/O.
+ Read = bindings::hctx_type_HCTX_TYPE_READ,
+ /// Polled I/O of any kind.
+ Poll = bindings::hctx_type_HCTX_TYPE_POLL,
+}
+
+impl TryFrom<u32> for QueueType {
+ type Error = kernel::error::Error;
+
+ fn try_from(value: u32) -> core::result::Result<Self, Self::Error> {
+ match value {
+ bindings::hctx_type_HCTX_TYPE_DEFAULT => Ok(QueueType::Default),
+ bindings::hctx_type_HCTX_TYPE_READ => Ok(QueueType::Read),
+ bindings::hctx_type_HCTX_TYPE_POLL => Ok(QueueType::Poll),
+ _ => Err(kernel::error::code::EINVAL),
+ }
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 51/79] block: rust: add polled completion support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (49 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 50/79] block: rust: add an abstraction for `struct blk_mq_queue_map` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 52/79] block: rust: add accessors to `TagSet` Andreas Hindborg
` (27 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for polled I/O completion to the Rust block layer bindings.
This includes the `poll` callback in `Operations` and the
`IoCompletionBatch` type for batched completions.
The `poll` callback is invoked by the block layer when polling for
completed requests on poll queues. Drivers can use `IoCompletionBatch`
to batch multiple completions efficiently.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 1 +
rust/helpers/blk.c | 7 +++
rust/kernel/block/mq.rs | 4 +-
rust/kernel/block/mq/operations.rs | 104 +++++++++++++++++++++++++++++++++++--
rust/kernel/block/mq/request.rs | 5 ++
5 files changed, 117 insertions(+), 4 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 48b2bd598304c..765bbc8101d10 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -733,6 +733,7 @@ fn queue_rq(
this: ArcBorrow<'_, Self>,
rq: Owned<mq::IdleRequest<Self>>,
_is_last: bool,
+ _is_poll: bool,
) -> BlkResult {
if this.bandwidth_limit != 0 {
if !this.bandwidth_timer.active() {
diff --git a/rust/helpers/blk.c b/rust/helpers/blk.c
index 53beba8c7782d..91b72131a04cd 100644
--- a/rust/helpers/blk.c
+++ b/rust/helpers/blk.c
@@ -20,3 +20,10 @@ void rust_helper_bio_advance_iter_single(const struct bio *bio,
{
bio_advance_iter_single(bio, iter, bytes);
}
+
+bool rust_helper_blk_mq_add_to_batch(struct request *req,
+ struct io_comp_batch *iob, bool is_error,
+ void (*complete)(struct io_comp_batch *))
+{
+ return blk_mq_add_to_batch(req, iob, is_error, complete);
+}
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index cd0bfbcbf317a..1d58eea971bd7 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -89,7 +89,8 @@
//! _hw_data: (),
//! _queue_data: (),
//! rq: Owned<IdleRequest<Self>>,
-//! _is_last: bool
+//! _is_last: bool,
+//! is_poll: bool
//! ) -> BlkResult {
//! rq.start().end_ok();
//! Ok(())
@@ -130,6 +131,7 @@
mod request_queue;
pub mod tag_set;
+pub use operations::IoCompletionBatch;
pub use operations::Operations;
pub use request::Command;
pub use request::IdleRequest;
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 28dd4b28d203f..bccc1903a0d10 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -65,6 +65,7 @@ fn queue_rq(
queue_data: ForeignBorrowed<'_, Self::QueueData>,
rq: Owned<IdleRequest<Self>>,
is_last: bool,
+ is_poll: bool,
) -> BlkResult;
/// Called by the kernel to indicate that queued requests should be submitted.
@@ -84,7 +85,15 @@ fn init_hctx(
/// Called by the kernel to poll the device for completed requests. Only
/// used for poll queues.
- fn poll(_hw_data: ForeignBorrowed<'_, Self::HwData>) -> bool {
+ ///
+ /// Should return `Ok(true)` if any requests were completed during the call,
+ /// `Ok(false)` if no requests were completed, and `Err(e)` to signal an
+ /// error condition.
+ fn poll(
+ _hw_data: ForeignBorrowed<'_, Self::HwData>,
+ _queue_data: ForeignBorrowed<'_, Self::QueueData>,
+ _batch: &mut IoCompletionBatch<Self>,
+ ) -> Result<bool> {
build_error!(crate::error::VTABLE_DEFAULT_ERROR)
}
@@ -168,6 +177,11 @@ impl<T: Operations> OperationsVTable<T> {
// `into_foreign` in `Self::init_hctx_callback`.
let hw_data = unsafe { T::HwData::borrow((*hctx).driver_data) };
+ let is_poll = u32::from(
+ // SAFETY: `hctx` is valid as required by this function.
+ unsafe { (*hctx).type_ },
+ ) == bindings::hctx_type_HCTX_TYPE_POLL;
+
// SAFETY: `hctx` is valid as required by this function.
let queue_data = unsafe { (*(*hctx).queue).queuedata };
@@ -184,6 +198,7 @@ impl<T: Operations> OperationsVTable<T> {
// SAFETY: `bd` is valid as required by the safety requirement for
// this function.
unsafe { (*bd).last },
+ is_poll,
);
if let Err(e) = ret {
@@ -242,13 +257,32 @@ impl<T: Operations> OperationsVTable<T> {
/// previously initialized by a call to `init_hctx_callback`.
unsafe extern "C" fn poll_callback(
hctx: *mut bindings::blk_mq_hw_ctx,
- _iob: *mut bindings::io_comp_batch,
+ iob: *mut bindings::io_comp_batch,
) -> crate::ffi::c_int {
// SAFETY: By function safety requirement, `hctx` was initialized by
// `init_hctx_callback` and thus `driver_data` came from a call to
// `into_foreign`.
let hw_data = unsafe { T::HwData::borrow((*hctx).driver_data) };
- T::poll(hw_data).into()
+
+ // SAFETY: `hctx` is valid as required by this function.
+ let queue_data = unsafe { (*(*hctx).queue).queuedata };
+
+ // SAFETY: `queue.queuedata` was created by `GenDiskBuilder::build` with
+ // a call to `ForeignOwnable::into_foreign` to create `queuedata`.
+ // `ForeignOwnable::from_foreign` is only called when the tagset is
+ // dropped, which happens after we are dropped.
+ let queue_data = unsafe { T::QueueData::borrow(queue_data) };
+
+ let mut batch = IoCompletionBatch {
+ inner: iob,
+ _p: PhantomData,
+ };
+
+ let ret = T::poll(hw_data, queue_data, &mut batch);
+ match ret {
+ Ok(val) => val.into(),
+ Err(e) => e.to_errno(),
+ }
}
/// This function is called by the C kernel. A pointer to this function is
@@ -448,3 +482,67 @@ pub(crate) const fn build() -> &'static bindings::blk_mq_ops {
&Self::VTABLE
}
}
+
+/// A batch of I/O completions for polled I/O.
+///
+/// This struct wraps the C `struct io_comp_batch` and is used to batch
+/// multiple request completions together for improved efficiency during polled
+/// I/O operations.
+///
+/// When the kernel polls for completed requests via [`Operations::poll`], it
+/// passes an `IoCompletionBatch` to collect completed requests. The driver can
+/// add completed requests to the batch using [`add_request`], allowing the
+/// kernel to process multiple completions together rather than one at a time.
+///
+/// # Invariants
+///
+/// - `inner` must point to a valid `io_comp_batch`.
+///
+/// [`add_request`]: IoCompletionBatch::add_request
+#[repr(transparent)]
+pub struct IoCompletionBatch<T> {
+ inner: *mut bindings::io_comp_batch,
+ _p: PhantomData<T>,
+}
+
+impl<T: Operations> IoCompletionBatch<T> {
+ /// Attempt to add a completed request to this batch.
+ ///
+ /// This method tries to add `rq` to the batch for deferred completion. If
+ /// the request is successfully added, ownership is transferred to the batch
+ /// and the request will be completed later when the batch is processed.
+ ///
+ /// # Arguments
+ ///
+ /// - `rq`: The completed request to add to the batch.
+ /// - `error`: Set to `true` if the request completed with an error.
+ ///
+ /// # Return
+ ///
+ /// When this method returns `Err`, the caller is responsible for completing
+ /// the request through other means, such as calling
+ /// [`Request::complete`](super::Request::complete).
+ pub fn add_request(
+ &mut self,
+ rq: Owned<Request<T>>,
+ error: bool,
+ ) -> Result<(), Owned<Request<T>>> {
+ // SAFETY: By type invariant, `self.inner` is a valid `io_comp_batch`.
+ let ret = unsafe {
+ bindings::blk_mq_add_to_batch(
+ rq.as_raw(),
+ self.inner,
+ error,
+ Some(bindings::blk_mq_end_request_batch),
+ )
+ };
+
+ match ret {
+ true => {
+ core::mem::forget(rq);
+ Ok(())
+ }
+ false => Err(rq),
+ }
+ }
+}
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 4e7adb10929f0..b4f5a98a97b16 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -135,6 +135,11 @@ pub fn queue(&self) -> &RequestQueue<T> {
// SAFETY: By type invariant, self.0 is guaranteed to be valid.
unsafe { RequestQueue::from_raw((*self.0.get()).q) }
}
+
+ /// Return a raw pointer to the underlying C structure.
+ pub fn as_raw(&self) -> *mut bindings::request {
+ self.0.get()
+ }
}
/// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 52/79] block: rust: add accessors to `TagSet`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (50 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 51/79] block: rust: add polled completion support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 53/79] block: rnull: add polled completion support Andreas Hindborg
` (26 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add `hw_queue_count()` to query the number of hardware queues and
`data()` to borrow the private tag set data associated with a `TagSet`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/tag_set.rs | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index e6edc5bc39312..4d00979a83dbd 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -4,8 +4,6 @@
//!
//! C header: [`include/linux/blk-mq.h`](srctree/include/linux/blk-mq.h)
-use core::pin::Pin;
-
use crate::{
bindings,
block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations},
@@ -13,7 +11,7 @@
try_pin_init,
types::{ForeignOwnable, Opaque},
};
-use core::{convert::TryInto, marker::PhantomData};
+use core::{convert::TryInto, marker::PhantomData, pin::Pin};
use pin_init::{pin_data, pinned_drop, PinInit};
mod flags;
@@ -137,6 +135,22 @@ pub fn update_maps(self: Pin<&mut Self>, mut cb: impl FnMut(QueueMap)) -> Result
Ok(())
}
+
+ /// Return the number of hardware queues for this tag set.
+ pub fn hw_queue_count(&self) -> u32 {
+ // SAFETY: By type invariant, `self.inner` is valid.
+ unsafe { (*self.inner.get()).nr_hw_queues }
+ }
+
+ /// Borrow the [`T::TagSetData`] associated with this tag set.
+ pub fn data(&self) -> <T::TagSetData as ForeignOwnable>::Borrowed<'_> {
+ // SAFETY: By type invariant, `self.inner` is valid.
+ let ptr = unsafe { (*self.inner.get()).driver_data };
+
+ // SAFETY: `ptr` was created by `into_foreign` during initialization and the target is not
+ // converted back with `from_foreign` while `&self` is live.
+ unsafe { T::TagSetData::borrow(ptr) }
+ }
}
#[pinned_drop]
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 53/79] block: rnull: add polled completion support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (51 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 52/79] block: rust: add accessors to `TagSet` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 54/79] block: rnull: add REQ_OP_FLUSH support Andreas Hindborg
` (25 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for polled I/O completion in rnull. This feature requires
configuring poll queues via the `poll_queues` attribute.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 19 +++++-
drivers/block/rnull/rnull.rs | 130 ++++++++++++++++++++++++++++++++++++----
2 files changed, 136 insertions(+), 13 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 0873d696f80f6..e134e21a6b564 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -71,7 +71,7 @@ impl AttributeOperations<0> for Config {
writer.write_str(
"blocksize,size,rotational,irqmode,completion_nsec,memory_backed\
submit_queues,use_per_node_hctx,discard,blocking,shared_tags,\
- zoned,zone_size,zone_capacity\n",
+ zoned,zone_size,zone_capacity,poll_queues\n",
)?;
Ok(writer.bytes_written())
}
@@ -117,6 +117,7 @@ fn make_group(
zone_max_open: 24,
zone_max_active: 25,
zone_append_max_sectors: 26,
+ poll_queues: 27,
],
};
@@ -156,6 +157,7 @@ fn make_group(
zone_max_open: 0,
zone_max_active: 0,
zone_append_max_sectors: u32::MAX,
+ poll_queues: 0,
}),
}),
core::iter::empty(),
@@ -231,6 +233,7 @@ struct DeviceConfigInner {
zone_max_open: u32,
zone_max_active: u32,
zone_append_max_sectors: u32,
+ poll_queues: u32,
}
#[vtable]
@@ -281,6 +284,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
zone_max_open: guard.zone_max_open,
zone_max_active: guard.zone_max_active,
zone_append_max_sectors: guard.zone_append_max_sectors,
+ poll_queues: guard.poll_queues,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -510,3 +514,16 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_field!(DeviceConfig, 24, zone_max_open, u32);
configfs_simple_field!(DeviceConfig, 25, zone_max_active, u32);
configfs_simple_field!(DeviceConfig, 26, zone_append_max_sectors, u32);
+configfs_simple_field!(
+ DeviceConfig,
+ 27,
+ poll_queues,
+ u32,
+ check | value | {
+ if value > kernel::num_possible_cpus() {
+ Err(kernel::error::code::EINVAL)
+ } else {
+ Ok(())
+ }
+ }
+);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 765bbc8101d10..92e75f15e02c6 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -33,6 +33,7 @@
GenDisk,
GenDiskRef, //
},
+ IoCompletionBatch,
Operations,
TagSet, //
},
@@ -188,6 +189,10 @@
default: 0,
description: "Maximum size of a zone append command (in 512B sectors). Specify 0 for no zone append.",
},
+ poll_queues: u32 {
+ default: 0,
+ description: "Number of IOPOLL submission queues.",
+ },
},
}
@@ -244,6 +249,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
zone_max_open: *module_parameters::zone_max_open.value(),
zone_max_active: *module_parameters::zone_max_active.value(),
zone_append_max_sectors: *module_parameters::zone_append_max_sectors.value(),
+ poll_queues: *module_parameters::poll_queues.value(),
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -291,6 +297,7 @@ struct NullBlkOptions<'a> {
zone_max_active: u32,
#[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
zone_append_max_sectors: u32,
+ poll_queues: u32,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -348,6 +355,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
zone_max_open,
zone_max_active,
zone_append_max_sectors,
+ poll_queues,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -369,7 +377,21 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
let tagset_ctor = || -> Result<Arc<_>> {
Arc::pin_init(
- TagSet::new(submit_queues, (), hw_queue_depth, 1, home_node, flags),
+ TagSet::new(
+ submit_queues + poll_queues,
+ KBox::new(
+ NullBlkTagsetData {
+ queue_depth: hw_queue_depth,
+ submit_queue_count: submit_queues,
+ poll_queue_count: poll_queues,
+ },
+ GFP_KERNEL,
+ )?,
+ hw_queue_depth,
+ if poll_queues == 0 { 1 } else { 3 },
+ home_node,
+ flags,
+ ),
GFP_KERNEL,
)
};
@@ -685,6 +707,7 @@ fn run(
struct HwQueueContext {
page: Option<KBox<disk_storage::NullBlockPage>>,
+ poll_queue: kernel::ringbuffer::RingBuffer<Owned<mq::Request<NullBlkDevice>>>,
}
#[pin_data]
@@ -713,11 +736,17 @@ impl HasHrTimer<Self> for Pdu {
}
}
+struct NullBlkTagsetData {
+ queue_depth: u32,
+ submit_queue_count: u32,
+ poll_queue_count: u32,
+}
+
#[vtable]
impl Operations for NullBlkDevice {
type QueueData = Arc<Self>;
type RequestData = Pdu;
- type TagSetData = ();
+ type TagSetData = KBox<NullBlkTagsetData>;
type HwData = Pin<KBox<SpinLock<HwQueueContext>>>;
fn new_request_data() -> impl PinInit<Self::RequestData> {
@@ -733,7 +762,7 @@ fn queue_rq(
this: ArcBorrow<'_, Self>,
rq: Owned<mq::IdleRequest<Self>>,
_is_last: bool,
- _is_poll: bool,
+ is_poll: bool,
) -> BlkResult {
if this.bandwidth_limit != 0 {
if !this.bandwidth_timer.active() {
@@ -770,13 +799,29 @@ fn queue_rq(
#[cfg(not(CONFIG_BLK_DEV_ZONED))]
this.handle_regular_command(&hw_data, &mut rq)?;
- match this.irq_mode {
- IRQMode::None => Self::end_request(rq),
- IRQMode::Soft => mq::Request::complete(rq.into()),
- IRQMode::Timer => {
- OwnableRefCounted::into_shared(rq)
- .start(this.completion_time)
- .dismiss();
+ if is_poll {
+ // NOTE: We lack the ability to insert `Owned<Request>` into a
+ // `kernel::list::List`, so we use a `RingBuffer` instead. The
+ // drawback of this is that we have to allocate the space for the
+ // ring buffer during drive initialization, and we have to hold the
+ // lock protecting the list until we have processed all the requests
+ // in the list. Change to a linked list when the kernel gets this
+ // ability.
+
+ // NOTE: We are processing requests during submit rather than during
+ // poll. This is different from C driver. C driver does processing
+ // during poll.
+
+ hw_data.lock().poll_queue.push_head(rq)?;
+ } else {
+ match this.irq_mode {
+ IRQMode::None => Self::end_request(rq),
+ IRQMode::Soft => mq::Request::complete(rq.into()),
+ IRQMode::Timer => {
+ OwnableRefCounted::into_shared(rq)
+ .start(this.completion_time)
+ .dismiss();
+ }
}
}
Ok(())
@@ -784,8 +829,39 @@ fn queue_rq(
fn commit_rqs(_hw_data: Pin<&SpinLock<HwQueueContext>>, _queue_data: ArcBorrow<'_, Self>) {}
- fn init_hctx(_tagset_data: (), _hctx_idx: u32) -> Result<Self::HwData> {
- KBox::pin_init(new_spinlock!(HwQueueContext { page: None }), GFP_KERNEL)
+ fn poll(
+ hw_data: Pin<&SpinLock<HwQueueContext>>,
+ _this: ArcBorrow<'_, Self>,
+ batch: &mut IoCompletionBatch<Self>,
+ ) -> Result<bool> {
+ let mut guard = hw_data.lock();
+ let mut completed = false;
+
+ while let Some(rq) = guard.poll_queue.pop_tail() {
+ let status = rq.data_ref().error.load(ordering::Relaxed);
+ rq.data_ref().error.store(0, ordering::Relaxed);
+
+ // TODO: check error handling via status
+ if let Err(rq) = batch.add_request(rq, status != 0) {
+ Self::end_request(rq);
+ }
+
+ completed = true;
+ }
+
+ Ok(completed)
+ }
+
+ fn init_hctx(tagset_data: &NullBlkTagsetData, _hctx_idx: u32) -> Result<Self::HwData> {
+ KBox::pin_init(
+ new_spinlock!(HwQueueContext {
+ page: None,
+ poll_queue: kernel::ringbuffer::RingBuffer::new(
+ tagset_data.queue_depth.try_into()?
+ )?,
+ }),
+ GFP_KERNEL,
+ )
}
fn complete(rq: ARef<mq::Request<Self>>) {
@@ -805,4 +881,34 @@ fn report_zones(
) -> Result<u32> {
Self::report_zones_internal(disk, sector, nr_zones, callback)
}
+
+ fn map_queues(tag_set: Pin<&mut TagSet<Self>>) {
+ let mut submit_queue_count = tag_set.data().submit_queue_count;
+ let mut poll_queue_count = tag_set.data().poll_queue_count;
+
+ if tag_set.hw_queue_count() != submit_queue_count + poll_queue_count {
+ pr_warn!(
+ "tag set has unexpected hardware queue count: {}\n",
+ tag_set.hw_queue_count()
+ );
+ submit_queue_count = 1;
+ poll_queue_count = 0;
+ }
+
+ let mut offset = 0;
+ tag_set
+ .update_maps(|mut qmap| {
+ use mq::QueueType::*;
+ let queue_count = match qmap.kind() {
+ Default => submit_queue_count,
+ Read => 0,
+ Poll => poll_queue_count,
+ };
+ qmap.set_queue_count(queue_count);
+ qmap.set_offset(offset);
+ offset += queue_count;
+ qmap.map_queues();
+ })
+ .unwrap()
+ }
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 54/79] block: rnull: add REQ_OP_FLUSH support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (52 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 53/79] block: rnull: add polled completion support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 55/79] block: rust: add request flags abstraction Andreas Hindborg
` (24 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for handling flush requests in rnull. When memory backing
and write cache are enabled, flush requests trigger a cache flush
operation that writes all dirty cache pages to the backing store.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/disk_storage.rs | 36 ++++++++++++++++++++++++++++--------
drivers/block/rnull/rnull.rs | 31 ++++++++++++++++++++++---------
2 files changed, 50 insertions(+), 17 deletions(-)
diff --git a/drivers/block/rnull/disk_storage.rs b/drivers/block/rnull/disk_storage.rs
index ce3e83671709a..a613ed5223ba7 100644
--- a/drivers/block/rnull/disk_storage.rs
+++ b/drivers/block/rnull/disk_storage.rs
@@ -85,6 +85,13 @@ pub(crate) fn discard(
remaining_bytes -= processed;
}
}
+
+ pub(crate) fn flush(&self, hw_data: &Pin<&SpinLock<HwQueueContext>>) -> Result {
+ let mut tree_guard = self.lock();
+ let mut hw_data_guard = hw_data.lock();
+ let mut access = self.access(&mut tree_guard, &mut hw_data_guard, None);
+ access.flush()
+ }
}
pub(crate) struct DiskStorageAccess<'a, 'b, 'c> {
@@ -118,13 +125,16 @@ fn to_sector(index: usize) -> u64 {
(index << block::PAGE_SECTORS_SHIFT) as u64
}
- fn extract_cache_page(&mut self) -> Result<KBox<NullBlockPage>> {
- let cache_entry = self
- .cache_guard
- .find_next_entry_circular(
- self.disk_storage.next_flush_sector.load(ordering::Relaxed) as usize
- )
- .expect("Expected to find a page in the cache");
+ fn extract_cache_page(&mut self) -> Result<Option<KBox<NullBlockPage>>> {
+ let cache_entry = self.cache_guard.find_next_entry_circular(
+ self.disk_storage.next_flush_sector.load(ordering::Relaxed) as usize,
+ );
+
+ let cache_entry = if let Some(entry) = cache_entry {
+ entry
+ } else {
+ return Ok(None);
+ };
let index = cache_entry.index();
@@ -168,7 +178,16 @@ fn extract_cache_page(&mut self) -> Result<KBox<NullBlockPage>> {
}
};
- Ok(page)
+ Ok(Some(page))
+ }
+
+ fn flush(&mut self) -> Result {
+ if self.disk_storage.cache_size > 0 {
+ while let Some(page) = self.extract_cache_page()? {
+ drop(page);
+ }
+ }
+ Ok(())
}
fn get_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
@@ -186,6 +205,7 @@ fn get_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
.expect("Expected to have a page available")
} else {
self.extract_cache_page()?
+ .expect("Expected to find a page in the cache")
};
Ok(self
.cache_guard
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 92e75f15e02c6..4870aa3b7a53e 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -673,6 +673,18 @@ fn end_request(rq: Owned<mq::Request<Self>>) {
_ => rq.end(bindings::BLK_STS_IOERR),
}
}
+
+ fn complete_request(&self, rq: Owned<mq::Request<Self>>) {
+ match self.irq_mode {
+ IRQMode::None => Self::end_request(rq),
+ IRQMode::Soft => mq::Request::complete(rq.into()),
+ IRQMode::Timer => {
+ OwnableRefCounted::into_shared(rq)
+ .start(self.completion_time)
+ .dismiss();
+ }
+ }
+ }
}
impl_has_hr_timer! {
@@ -789,6 +801,15 @@ fn queue_rq(
let mut rq = rq.start();
+ if rq.command() == mq::Command::Flush {
+ if this.memory_backed {
+ this.storage.flush(&hw_data)?;
+ }
+ this.complete_request(rq);
+
+ return Ok(());
+ }
+
#[cfg(CONFIG_BLK_DEV_ZONED)]
if this.zoned.enabled {
this.handle_zoned_command(&hw_data, &mut rq)?;
@@ -814,15 +835,7 @@ fn queue_rq(
hw_data.lock().poll_queue.push_head(rq)?;
} else {
- match this.irq_mode {
- IRQMode::None => Self::end_request(rq),
- IRQMode::Soft => mq::Request::complete(rq.into()),
- IRQMode::Timer => {
- OwnableRefCounted::into_shared(rq)
- .start(this.completion_time)
- .dismiss();
- }
- }
+ this.complete_request(rq);
}
Ok(())
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 55/79] block: rust: add request flags abstraction
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (53 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 54/79] block: rnull: add REQ_OP_FLUSH support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 56/79] block: rust: add abstraction for block queue feature flags Andreas Hindborg
` (23 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add the `Flag` enum and `Flags` type as Rust abstractions for the C
`REQ_*` request flags. These flags modify how block I/O requests are
processed, including sync behavior, priority hints, and integrity
settings.
Also add a `flags()` method to `Request` to retrieve the flags for a
given request.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/bindings/bindings_helper.h | 21 ++++++++++++
rust/kernel/block/mq.rs | 2 ++
rust/kernel/block/mq/request.rs | 9 ++++++
rust/kernel/block/mq/request/flag.rs | 62 ++++++++++++++++++++++++++++++++++++
4 files changed, 94 insertions(+)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 05133a78ecf95..b8c2f3eadc730 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -134,6 +134,27 @@ const blk_status_t RUST_CONST_HELPER_BLK_STS_OFFLINE = BLK_STS_OFFLINE;
const blk_status_t RUST_CONST_HELPER_BLK_STS_DURATION_LIMIT = BLK_STS_DURATION_LIMIT;
const blk_status_t RUST_CONST_HELPER_BLK_STS_INVAL = BLK_STS_INVAL;
const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ZONED = BLK_FEAT_ZONED;
+const blk_opf_t RUST_CONST_HELPER_REQ_FAILFAST_DEV = REQ_FAILFAST_DEV;
+const blk_opf_t RUST_CONST_HELPER_REQ_FAILFAST_TRANSPORT = REQ_FAILFAST_TRANSPORT;
+const blk_opf_t RUST_CONST_HELPER_REQ_FAILFAST_DRIVER = REQ_FAILFAST_DRIVER;
+const blk_opf_t RUST_CONST_HELPER_REQ_SYNC = REQ_SYNC;
+const blk_opf_t RUST_CONST_HELPER_REQ_META = REQ_META;
+const blk_opf_t RUST_CONST_HELPER_REQ_PRIO = REQ_PRIO;
+const blk_opf_t RUST_CONST_HELPER_REQ_NOMERGE = REQ_NOMERGE;
+const blk_opf_t RUST_CONST_HELPER_REQ_IDLE = REQ_IDLE;
+const blk_opf_t RUST_CONST_HELPER_REQ_INTEGRITY = REQ_INTEGRITY;
+const blk_opf_t RUST_CONST_HELPER_REQ_FUA = REQ_FUA;
+const blk_opf_t RUST_CONST_HELPER_REQ_PREFLUSH = REQ_PREFLUSH;
+const blk_opf_t RUST_CONST_HELPER_REQ_RAHEAD = REQ_RAHEAD;
+const blk_opf_t RUST_CONST_HELPER_REQ_BACKGROUND = REQ_BACKGROUND;
+const blk_opf_t RUST_CONST_HELPER_REQ_NOWAIT = REQ_NOWAIT;
+const blk_opf_t RUST_CONST_HELPER_REQ_POLLED = REQ_POLLED;
+const blk_opf_t RUST_CONST_HELPER_REQ_ALLOC_CACHE = REQ_ALLOC_CACHE;
+const blk_opf_t RUST_CONST_HELPER_REQ_SWAP = REQ_SWAP;
+const blk_opf_t RUST_CONST_HELPER_REQ_DRV = REQ_DRV;
+const blk_opf_t RUST_CONST_HELPER_REQ_FS_PRIVATE = REQ_FS_PRIVATE;
+const blk_opf_t RUST_CONST_HELPER_REQ_ATOMIC = REQ_ATOMIC;
+const blk_opf_t RUST_CONST_HELPER_REQ_NOUNMAP = REQ_NOUNMAP;
const fop_flags_t RUST_CONST_HELPER_FOP_UNSIGNED_OFFSET = FOP_UNSIGNED_OFFSET;
const xa_mark_t RUST_CONST_HELPER_XA_PRESENT = XA_PRESENT;
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 1d58eea971bd7..5a1c8e914bb9e 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -134,6 +134,8 @@
pub use operations::IoCompletionBatch;
pub use operations::Operations;
pub use request::Command;
+pub use request::Flag as RequestFlag;
+pub use request::Flags as RequestFlags;
pub use request::IdleRequest;
pub use request::Request;
pub use request::RequestTimerHandle;
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index b4f5a98a97b16..cebb30fe9b3bc 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -27,6 +27,9 @@
mod command;
pub use command::Command;
+mod flag;
+pub use flag::{Flag, Flags};
+
/// A [`Request`] that a driver has not yet begun to process.
///
/// A driver can convert an `IdleRequest` to a [`Request`] by calling [`IdleRequest::start`].
@@ -104,6 +107,12 @@ pub fn command(&self) -> Command {
unsafe { Command::from_raw(self.command_raw()) }
}
+ pub fn flags(&self) -> Flags {
+ // SAFETY: By C API contract and type invariant, `cmd_flags` is valid for read
+ let flags = unsafe { (*self.0.get()).cmd_flags & !((1 << bindings::REQ_OP_BITS) - 1) };
+ Flags::try_from(flags).expect("Request should have valid falgs")
+ }
+
/// Get the target sector for the request.
#[inline(always)]
pub fn sector(&self) -> u64 {
diff --git a/rust/kernel/block/mq/request/flag.rs b/rust/kernel/block/mq/request/flag.rs
new file mode 100644
index 0000000000000..47d25224a1ab4
--- /dev/null
+++ b/rust/kernel/block/mq/request/flag.rs
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+use kernel::prelude::*;
+
+impl_flags! {
+ /// A set of request flags.
+ ///
+ /// This type wraps the C `REQ_*` flags and allows combining multiple flags
+ /// together. These flags modify how a block I/O request is processed.
+ #[derive(Debug, Clone, Default, Copy, PartialEq, Eq)]
+ pub struct Flags(u32);
+
+ /// Individual request flags for block I/O operations.
+ ///
+ /// These flags correspond to the C `REQ_*` defines in `linux/blk_types.h`
+ /// and are used to modify the behavior of block I/O requests.
+ #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+ pub enum Flag {
+ /// No driver retries on device errors.
+ FailfastDev = bindings::REQ_FAILFAST_DEV,
+ /// No driver retries on transport errors.
+ FailfastTransport = bindings::REQ_FAILFAST_TRANSPORT,
+ /// No driver retries on driver errors.
+ FailfastDriver = bindings::REQ_FAILFAST_DRIVER,
+ /// Request is synchronous (sync write or read).
+ Sync = bindings::REQ_SYNC,
+ /// Metadata I/O request.
+ Meta = bindings::REQ_META,
+ /// Boost priority in CFQ scheduler.
+ Priority = bindings::REQ_PRIO,
+ /// Don't merge this request with others.
+ NoMerge = bindings::REQ_NOMERGE,
+ /// Anticipate more I/O after this one.
+ Idle = bindings::REQ_IDLE,
+ /// I/O includes block integrity payload.
+ Integrity = bindings::REQ_INTEGRITY,
+ /// Forced unit access - data must be written to persistent storage
+ /// before command completion is signaled.
+ ForcedUnitAccess = bindings::REQ_FUA,
+ /// Request a cache flush before this operation.
+ Preflush = bindings::REQ_PREFLUSH,
+ /// Read ahead request, can fail anytime.
+ ReadAhead = bindings::REQ_RAHEAD,
+ /// Background I/O operation.
+ Background = bindings::REQ_BACKGROUND,
+ /// Don't wait if the request would block.
+ NoWait = bindings::REQ_NOWAIT,
+ /// Caller polls for completion using `bio_poll`.
+ Polled = bindings::REQ_POLLED,
+ /// Allocate I/O from cache if available.
+ AllocCache = bindings::REQ_ALLOC_CACHE,
+ /// Swap I/O operation.
+ Swap = bindings::REQ_SWAP,
+ /// Reserved for driver use.
+ Driver = bindings::REQ_DRV,
+ /// Reserved for file system (submitter) use.
+ FsPrivate = bindings::REQ_FS_PRIVATE,
+ /// Atomic write operation.
+ Atomic = bindings::REQ_ATOMIC,
+ /// Do not free blocks when zeroing (for write zeroes operations).
+ NoUnmap = bindings::REQ_NOUNMAP,
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 56/79] block: rust: add abstraction for block queue feature flags
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (54 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 55/79] block: rust: add request flags abstraction Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 57/79] block: rust: allow setting write cache and FUA flags for `GenDisk` Andreas Hindborg
` (22 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add the `Feature` enum and `Features` type as Rust abstractions for the
C `blk_features_t` bitfield. These types wrap the `BLK_FEAT_*` flags
and allow drivers to describe block device capabilities such as write
cache support, FUA, rotational media, and DAX.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/bindings/bindings_helper.h | 15 ++++++++-
rust/kernel/block/mq.rs | 2 ++
rust/kernel/block/mq/feature.rs | 73 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 89 insertions(+), 1 deletion(-)
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index b8c2f3eadc730..209c53443e9cb 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -113,7 +113,6 @@ const gfp_t RUST_CONST_HELPER_GFP_NOWAIT = GFP_NOWAIT;
const gfp_t RUST_CONST_HELPER___GFP_ZERO = __GFP_ZERO;
const gfp_t RUST_CONST_HELPER___GFP_HIGHMEM = ___GFP_HIGHMEM;
const gfp_t RUST_CONST_HELPER___GFP_NOWARN = ___GFP_NOWARN;
-const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ROTATIONAL = BLK_FEAT_ROTATIONAL;
const blk_status_t RUST_CONST_HELPER_BLK_STS_OK = BLK_STS_OK;
const blk_status_t RUST_CONST_HELPER_BLK_STS_NOTSUPP = BLK_STS_NOTSUPP;
const blk_status_t RUST_CONST_HELPER_BLK_STS_TIMEOUT = BLK_STS_TIMEOUT;
@@ -133,7 +132,21 @@ const blk_status_t RUST_CONST_HELPER_BLK_STS_ZONE_ACTIVE_RESOURCE = BLK_STS_ZONE
const blk_status_t RUST_CONST_HELPER_BLK_STS_OFFLINE = BLK_STS_OFFLINE;
const blk_status_t RUST_CONST_HELPER_BLK_STS_DURATION_LIMIT = BLK_STS_DURATION_LIMIT;
const blk_status_t RUST_CONST_HELPER_BLK_STS_INVAL = BLK_STS_INVAL;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_WRITE_CACHE = BLK_FEAT_WRITE_CACHE;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_FUA = BLK_FEAT_FUA;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ROTATIONAL = BLK_FEAT_ROTATIONAL;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ADD_RANDOM = BLK_FEAT_ADD_RANDOM;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_IO_STAT = BLK_FEAT_IO_STAT;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_STABLE_WRITES = BLK_FEAT_STABLE_WRITES;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_SYNCHRONOUS = BLK_FEAT_SYNCHRONOUS;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_NOWAIT = BLK_FEAT_NOWAIT;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_DAX = BLK_FEAT_DAX;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_POLL = BLK_FEAT_POLL;
const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ZONED = BLK_FEAT_ZONED;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_PCI_P2PDMA = BLK_FEAT_PCI_P2PDMA;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_SKIP_TAGSET_QUIESCE = BLK_FEAT_SKIP_TAGSET_QUIESCE;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE = BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE;
+const blk_features_t RUST_CONST_HELPER_BLK_FEAT_ATOMIC_WRITES = BLK_FEAT_ATOMIC_WRITES;
const blk_opf_t RUST_CONST_HELPER_REQ_FAILFAST_DEV = REQ_FAILFAST_DEV;
const blk_opf_t RUST_CONST_HELPER_REQ_FAILFAST_TRANSPORT = REQ_FAILFAST_TRANSPORT;
const blk_opf_t RUST_CONST_HELPER_REQ_FAILFAST_DRIVER = REQ_FAILFAST_DRIVER;
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 5a1c8e914bb9e..b36112f7b22b9 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -125,12 +125,14 @@
//! # Ok::<(), kernel::error::Error>(())
//! ```
+mod feature;
pub mod gen_disk;
mod operations;
mod request;
mod request_queue;
pub mod tag_set;
+pub use feature::{Feature, Features};
pub use operations::IoCompletionBatch;
pub use operations::Operations;
pub use request::Command;
diff --git a/rust/kernel/block/mq/feature.rs b/rust/kernel/block/mq/feature.rs
new file mode 100644
index 0000000000000..6c9f098e10c55
--- /dev/null
+++ b/rust/kernel/block/mq/feature.rs
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Block device feature flags.
+//!
+//! This module provides Rust abstractions for the C `blk_features_t` type and
+//! the associated `BLK_FEAT_*` flags defined in `include/linux/blkdev.h`.
+
+use kernel::prelude::*;
+
+impl_flags! {
+ /// A set of block device feature flags.
+ ///
+ /// This type wraps the C `blk_features_t` bitfield and represents a
+ /// combination of zero or more [`Feature`] flags. It is used to describe
+ /// the capabilities of a block device in [`struct queue_limits`].
+ ///
+ /// [`struct queue_limits`]: srctree/include/linux/blkdev.h
+ #[derive(Debug, Clone, Default, Copy, PartialEq, Eq)]
+ pub struct Features(u32);
+
+ /// A block device feature flag.
+ ///
+ /// Each variant corresponds to a `BLK_FEAT_*` constant defined in
+ /// `include/linux/blkdev.h`. These flags describe individual capabilities
+ /// or properties of a block device.
+ #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+ pub enum Feature {
+ /// Supports a volatile write cache.
+ WriteCache = bindings::BLK_FEAT_WRITE_CACHE,
+
+ /// Supports passing on the FUA bit.
+ ForcedUnitAccess = bindings::BLK_FEAT_FUA,
+
+ /// Rotational device (hard drive or floppy).
+ Rotational = bindings::BLK_FEAT_ROTATIONAL,
+
+ /// Contributes to the random number pool.
+ AddRandom = bindings::BLK_FEAT_ADD_RANDOM,
+
+ /// Enables disk/partitions I/O accounting.
+ IoStat = bindings::BLK_FEAT_IO_STAT,
+
+ /// Don't modify data until writeback is done.
+ StableWrites = bindings::BLK_FEAT_STABLE_WRITES,
+
+ /// Always completes in submit context.
+ Synchronous = bindings::BLK_FEAT_SYNCHRONOUS,
+
+ /// Supports REQ_NOWAIT.
+ Nowait = bindings::BLK_FEAT_NOWAIT,
+
+ /// Supports DAX.
+ Dax = bindings::BLK_FEAT_DAX,
+
+ /// Supports I/O polling.
+ Poll = bindings::BLK_FEAT_POLL,
+
+ /// Is a zoned device.
+ Zoned = bindings::BLK_FEAT_ZONED,
+
+ /// Supports PCI(e) p2p requests.
+ PciP2Pdma = bindings::BLK_FEAT_PCI_P2PDMA,
+
+ /// Skips this queue in `blk_mq_(un)quiesce_tagset`.
+ SkipTagsetQuiesce = bindings::BLK_FEAT_SKIP_TAGSET_QUIESCE,
+
+ /// Undocumented magic for bcache.
+ RaidPartialStripesExpensive = bindings::BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE,
+
+ /// Atomic writes enabled.
+ AtomicWrites = bindings::BLK_FEAT_ATOMIC_WRITES,
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 57/79] block: rust: allow setting write cache and FUA flags for `GenDisk`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (55 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 56/79] block: rust: add abstraction for block queue feature flags Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 58/79] block: rust: add `Segment::copy_to_page_limit` Andreas Hindborg
` (21 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add methods to `GenDiskBuilder` for enabling the write cache and FUA
feature flags. These flags are set in the `queue_limits` structure
when building the disk.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/gen_disk.rs | 30 +++++++++++++++++++++++++++---
1 file changed, 27 insertions(+), 3 deletions(-)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index a6f113ea4bea4..c6b9839864012 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -7,7 +7,7 @@
use crate::{
bindings,
- block::mq::{operations::OperationsVTable, Operations, RequestQueue, TagSet},
+ block::mq::{operations::OperationsVTable, Feature, Operations, RequestQueue, TagSet},
error::{self, from_err_ptr, Result},
fmt::{self, Write},
prelude::*,
@@ -34,6 +34,8 @@ pub struct GenDiskBuilder<T> {
zone_size_sectors: u32,
#[cfg(CONFIG_BLK_DEV_ZONED)]
zone_append_max_sectors: u32,
+ write_cache: bool,
+ forced_unit_access: bool,
_p: PhantomData<T>,
}
@@ -51,6 +53,8 @@ fn default() -> Self {
zone_size_sectors: 0,
#[cfg(CONFIG_BLK_DEV_ZONED)]
zone_append_max_sectors: 0,
+ write_cache: false,
+ forced_unit_access: false,
_p: PhantomData,
}
}
@@ -143,6 +147,18 @@ pub fn zone_append_max(mut self, sectors: u32) -> Self {
self
}
+ /// Declare that this device supports forced unit access.
+ pub fn forced_unit_access(mut self, enable: bool) -> Self {
+ self.forced_unit_access = enable;
+ self
+ }
+
+ /// Declare that this device has a write-back cache.
+ pub fn write_cache(mut self, enable: bool) -> Self {
+ self.write_cache = enable;
+ self
+ }
+
/// Build a new `GenDisk` and add it to the VFS.
pub fn build(
self,
@@ -163,7 +179,7 @@ pub fn build(
lim.physical_block_size = self.physical_block_size;
lim.max_hw_discard_sectors = self.max_hw_discard_sectors;
if self.rotational {
- lim.features |= bindings::BLK_FEAT_ROTATIONAL;
+ lim.features = Feature::Rotational.into();
}
#[cfg(CONFIG_BLK_DEV_ZONED)]
@@ -172,11 +188,19 @@ pub fn build(
return Err(error::code::EINVAL);
}
- lim.features |= bindings::BLK_FEAT_ZONED;
+ //lim.features |= request::Feature::Zoned.into();
lim.chunk_sectors = self.zone_size_sectors;
lim.max_hw_zone_append_sectors = self.zone_append_max_sectors;
}
+ if self.write_cache {
+ lim.features |= Feature::WriteCache;
+ }
+
+ if self.forced_unit_access {
+ lim.features |= Feature::ForcedUnitAccess;
+ }
+
// SAFETY: `tagset.raw_tag_set()` points to a valid and initialized tag set
let gendisk = from_err_ptr(unsafe {
bindings::__blk_mq_alloc_disk(
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 58/79] block: rust: add `Segment::copy_to_page_limit`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (56 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 57/79] block: rust: allow setting write cache and FUA flags for `GenDisk` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 59/79] block: rnull: add fua support Andreas Hindborg
` (20 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method to `block::mq::bio::Segment` to copy a bounded amount of bytes
to a page.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/bio/vec.rs | 27 ++++++++++++++++++++++++++-
rust/kernel/block/mq/request.rs | 3 +--
2 files changed, 27 insertions(+), 3 deletions(-)
diff --git a/rust/kernel/block/bio/vec.rs b/rust/kernel/block/bio/vec.rs
index 20cea478050b9..ed1c1374c9c76 100644
--- a/rust/kernel/block/bio/vec.rs
+++ b/rust/kernel/block/bio/vec.rs
@@ -79,13 +79,38 @@ pub fn advance(&mut self, count: u32) -> Result {
/// Returns the number of bytes copied.
#[inline(always)]
pub fn copy_to_page(&mut self, dst_page: Pin<&mut SafePage>, dst_offset: usize) -> usize {
+ self.copy_to_page_limit(dst_page, dst_offset, 0)
+ }
+
+ /// Copy data of this segment into `dst_page`.
+ ///
+ /// Copies at most `limit` bytes of data from the current offset to the next page boundary. That
+ /// is `PAGE_SIZE - (self.offeset() % PAGE_SIZE)` bytes of data. Data is placed at offset
+ /// `self.offset()` in the target page. This call will advance offset and reduce length of
+ /// `self`.
+ ///
+ /// If `limit` is zero it is ignored.
+ ///
+ /// Returns the number of bytes copied.
+ #[inline(always)]
+ pub fn copy_to_page_limit(
+ &mut self,
+ dst_page: Pin<&mut SafePage>,
+ dst_offset: usize,
+ limit: usize,
+ ) -> usize {
// SAFETY: We are not moving out of `dst_page`.
let dst_page = unsafe { Pin::into_inner_unchecked(dst_page) };
let src_offset = self.offset() % PAGE_SIZE;
debug_assert!(dst_offset <= PAGE_SIZE);
- let length = (PAGE_SIZE - src_offset)
+ let mut length = (PAGE_SIZE - src_offset)
.min(self.len() as usize)
.min(PAGE_SIZE - dst_offset);
+
+ if limit > 0 {
+ length = length.min(limit);
+ }
+
let page_idx = self.offset() / PAGE_SIZE;
// SAFETY: self.bio_vec is valid and thus bv_page must be a valid
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index cebb30fe9b3bc..bc655d202ca01 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -7,7 +7,6 @@
use crate::{
bindings,
block::mq::Operations,
- prelude::*,
sync::{
aref::{ARef, RefCounted},
atomic::ordering,
@@ -18,7 +17,7 @@
},
types::{ForeignOwnable, Opaque, Ownable, OwnableRefCounted, Owned},
};
-use core::{ffi::c_void, marker::PhantomData, ops::Deref, ptr::NonNull};
+use core::{ffi::c_void, marker::PhantomData, ops::Deref, pin::Pin, ptr::NonNull};
use super::RequestQueue;
use crate::block::bio::Bio;
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 59/79] block: rnull: add fua support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (57 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 58/79] block: rust: add `Segment::copy_to_page_limit` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 60/79] block: fix arg type in `blk_mq_update_nr_hw_queues` Andreas Hindborg
` (19 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add Forced Unit Access (FUA) support to rnull. When enabled via the `fua`
configfs attribute, the driver advertises FUA capability and handles FUA
requests by bypassing the volatile cache in the write path.
FUA support requires memory backing and write cache to be enabled.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 5 ++++
drivers/block/rnull/disk_storage.rs | 22 +++++++++++++---
drivers/block/rnull/disk_storage/page.rs | 1 +
drivers/block/rnull/rnull.rs | 45 ++++++++++++++++++++++++--------
4 files changed, 58 insertions(+), 15 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index e134e21a6b564..816c057f130fc 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -118,6 +118,7 @@ fn make_group(
zone_max_active: 25,
zone_append_max_sectors: 26,
poll_queues: 27,
+ fua: 28,
],
};
@@ -158,6 +159,7 @@ fn make_group(
zone_max_active: 0,
zone_append_max_sectors: u32::MAX,
poll_queues: 0,
+ fua: true,
}),
}),
core::iter::empty(),
@@ -234,6 +236,7 @@ struct DeviceConfigInner {
zone_max_active: u32,
zone_append_max_sectors: u32,
poll_queues: u32,
+ fua: bool,
}
#[vtable]
@@ -285,6 +288,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
zone_max_active: guard.zone_max_active,
zone_append_max_sectors: guard.zone_append_max_sectors,
poll_queues: guard.poll_queues,
+ forced_unit_access: guard.fua,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -527,3 +531,4 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
);
+configfs_simple_bool_field!(DeviceConfig, 28, fua);
diff --git a/drivers/block/rnull/disk_storage.rs b/drivers/block/rnull/disk_storage.rs
index a613ed5223ba7..b2b5eaa783cdc 100644
--- a/drivers/block/rnull/disk_storage.rs
+++ b/drivers/block/rnull/disk_storage.rs
@@ -92,6 +92,10 @@ pub(crate) fn flush(&self, hw_data: &Pin<&SpinLock<HwQueueContext>>) -> Result {
let mut access = self.access(&mut tree_guard, &mut hw_data_guard, None);
access.flush()
}
+
+ pub(crate) fn cache_enabled(&self) -> bool {
+ self.cache_size > 0
+ }
}
pub(crate) struct DiskStorageAccess<'a, 'b, 'c> {
@@ -190,7 +194,7 @@ fn flush(&mut self) -> Result {
Ok(())
}
- fn get_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
+ fn get_or_alloc_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
let index = Self::to_index(sector);
if self.cache_guard.contains_index(index) {
@@ -215,6 +219,12 @@ fn get_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
}
}
+ pub(crate) fn get_cache_page(&mut self, sector: u64) -> Option<&mut NullBlockPage> {
+ let index = Self::to_index(sector);
+
+ self.cache_guard.get_mut(index)
+ }
+
fn get_disk_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
let index = Self::to_index(sector);
@@ -232,9 +242,13 @@ fn get_disk_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
Ok(page)
}
- pub(crate) fn get_write_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
- let page = if self.disk_storage.cache_size > 0 {
- self.get_cache_page(sector)?
+ pub(crate) fn get_write_page(
+ &mut self,
+ sector: u64,
+ bypass_cache: bool,
+ ) -> Result<&mut NullBlockPage> {
+ let page = if self.disk_storage.cache_size > 0 && !bypass_cache {
+ self.get_or_alloc_cache_page(sector)?
} else {
self.get_disk_page(sector)?
};
diff --git a/drivers/block/rnull/disk_storage/page.rs b/drivers/block/rnull/disk_storage/page.rs
index a34fe0762724d..728073d5dd23d 100644
--- a/drivers/block/rnull/disk_storage/page.rs
+++ b/drivers/block/rnull/disk_storage/page.rs
@@ -14,6 +14,7 @@
uapi::PAGE_SECTORS, //
};
+// TODO: Use rust bitmap
const _CHEKC_STATUS_WIDTH: () = build_assert!((PAGE_SIZE >> SECTOR_SHIFT) <= 64);
pub(crate) struct NullBlockPage {
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 4870aa3b7a53e..3b7edfe7efe44 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -193,6 +193,10 @@
default: 0,
description: "Number of IOPOLL submission queues.",
},
+ fua: u8 {
+ default: 1,
+ description: "Enable/disable FUA support when cache_size is used. Default: 1 (true)",
+ },
},
}
@@ -250,6 +254,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
zone_max_active: *module_parameters::zone_max_active.value(),
zone_append_max_sectors: *module_parameters::zone_append_max_sectors.value(),
poll_queues: *module_parameters::poll_queues.value(),
+ forced_unit_access: *module_parameters::fua.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -298,6 +303,7 @@ struct NullBlkOptions<'a> {
#[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
zone_append_max_sectors: u32,
poll_queues: u32,
+ forced_unit_access: bool,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -356,13 +362,11 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
zone_max_active,
zone_append_max_sectors,
poll_queues,
+ forced_unit_access,
} = options;
let mut flags = mq::tag_set::Flags::default();
- // TODO: lim.features |= BLK_FEAT_WRITE_CACHE;
- // if (dev->fua)
- // lim.features |= BLK_FEAT_FUA;
if blocking || memory_backed {
flags |= mq::tag_set::Flag::Blocking;
}
@@ -404,9 +408,10 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
let device_capacity_sectors = mib_to_sectors(device_capacity_mib);
+ let s = storage.clone();
let queue_data = Arc::try_pin_init(
try_pin_init!(Self {
- storage,
+ storage: s,
irq_mode,
completion_time,
memory_backed,
@@ -439,7 +444,9 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
.capacity_sectors(device_capacity_sectors)
.logical_block_size(block_size_bytes)?
.physical_block_size(block_size_bytes)?
- .rotational(rotational);
+ .rotational(rotational)
+ .write_cache(storage.cache_enabled())
+ .forced_unit_access(forced_unit_access && storage.cache_enabled());
#[cfg(CONFIG_BLK_DEV_ZONED)]
{
@@ -496,6 +503,7 @@ fn write<'a, 'b, 'c>(
hw_data_guard: &'b mut SpinLockGuard<'c, HwQueueContext>,
mut sector: u64,
mut segment: Segment<'_>,
+ bypass_cache: bool,
) -> Result {
let mut sheaf: Option<XArraySheaf<'_>> = None;
@@ -524,12 +532,21 @@ fn write<'a, 'b, 'c>(
let mut access = self.storage.access(tree_guard, hw_data_guard, sheaf);
- let page = access.get_write_page(sector)?;
+ if bypass_cache {
+ if let Some(page) = access.get_cache_page(sector) {
+ page.set_free(sector);
+ }
+ }
+
+ let page = access.get_write_page(sector, bypass_cache)?;
page.set_occupied(sector);
let page_offset = (sector & u64::from(block::SECTOR_MASK)) << block::SECTOR_SHIFT;
- sector += segment.copy_to_page(page.page_mut().get_pin_mut(), page_offset as usize)
- as u64
+ sector += segment.copy_to_page_limit(
+ page.page_mut().get_pin_mut(),
+ page_offset as usize,
+ self.block_size_bytes.try_into()?,
+ ) as u64
>> block::SECTOR_SHIFT;
sheaf = access.sheaf;
@@ -588,6 +605,8 @@ fn transfer(
let mut hw_data_guard = hw_data.lock();
let mut tree_guard = self.storage.lock();
+ let skip_cache = rq.flags().contains(mq::RequestFlag::ForcedUnitAccess);
+
for bio in rq.bio_iter_mut() {
let segment_iter = bio.segment_iter();
for segment in segment_iter {
@@ -596,9 +615,13 @@ fn transfer(
.len()
.min((end_sector - sector) as u32 >> SECTOR_SHIFT);
match command {
- mq::Command::Write => {
- self.write(&mut tree_guard, &mut hw_data_guard, sector, segment)?
- }
+ mq::Command::Write => self.write(
+ &mut tree_guard,
+ &mut hw_data_guard,
+ sector,
+ segment,
+ skip_cache,
+ )?,
mq::Command::Read => {
self.read(&mut tree_guard, &mut hw_data_guard, sector, segment)?
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 60/79] block: fix arg type in `blk_mq_update_nr_hw_queues`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (58 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 59/79] block: rnull: add fua support Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 61/79] block: rust: add `GenDisk::tag_set` Andreas Hindborg
` (18 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
The type of the argument `nr_hw_queues` in the function
`blk_mq_update_nr_hw_queues` is a signed integer. This is wrong,
considering the field `nr_hw_queues` of `struct blk_mq_tag_set` is
unsigned. Thus, change the type of the parameter to unsigned.
Cascade the change to downstream functions.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
block/blk-mq.c | 13 +++++++------
include/linux/blk-mq.h | 2 +-
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a29d8ac9d3e35..6a44ebb6aac43 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4779,10 +4779,10 @@ static void blk_mq_update_queue_map(struct blk_mq_tag_set *set)
}
static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
- int new_nr_hw_queues)
+ unsigned int new_nr_hw_queues)
{
struct blk_mq_tags **new_tags;
- int i;
+ unsigned int i;
if (set->nr_hw_queues >= new_nr_hw_queues)
goto done;
@@ -5086,12 +5086,12 @@ static int blk_mq_elv_switch_none(struct request_queue *q,
}
static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
- int nr_hw_queues)
+ unsigned int nr_hw_queues)
{
struct request_queue *q;
- int prev_nr_hw_queues = set->nr_hw_queues;
+ unsigned int prev_nr_hw_queues = set->nr_hw_queues;
unsigned int memflags;
- int i;
+ unsigned int i;
struct xarray elv_tbl;
bool queues_frozen = false;
@@ -5178,7 +5178,8 @@ static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
__blk_mq_free_map_and_rqs(set, i);
}
-void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
+void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
+ unsigned int nr_hw_queues)
{
down_write(&set->update_nr_hwq_lock);
mutex_lock(&set->tag_list_lock);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index cae9e857aea42..171521e716e49 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -972,7 +972,7 @@ unsigned int blk_mq_num_online_queues(unsigned int max_queues);
void blk_mq_map_queues(struct blk_mq_queue_map *qmap);
void blk_mq_map_hw_queues(struct blk_mq_queue_map *qmap,
struct device *dev, unsigned int offset);
-void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues);
+void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, unsigned int nr_hw_queues);
void blk_mq_quiesce_queue_nowait(struct request_queue *q);
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 61/79] block: rust: add `GenDisk::tag_set`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (59 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 60/79] block: fix arg type in `blk_mq_update_nr_hw_queues` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count` Andreas Hindborg
` (17 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method to `GenDisk` to obtain a reference to the associated `TagSet`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/gen_disk.rs | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index c6b9839864012..b5291bc3e051d 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -236,7 +236,7 @@ pub fn build(
// `__blk_mq_alloc_disk` above.
let mut disk = UniqueArc::new(
GenDisk {
- _tagset: tagset,
+ tag_set: tagset,
gendisk,
backref: Arc::pin_init(
// INVARIANT: We break `GenDiskRef` invariant here, but we restore it below.
@@ -320,7 +320,7 @@ pub(crate) const fn build_vtable() -> &'static bindings::block_device_operations
/// `bindings::device_add_disk`.
/// - `self.gendisk.queue.queuedata` is initialized by a call to `ForeignOwnable::into_foreign`.
pub struct GenDisk<T: Operations> {
- _tagset: Arc<TagSet<T>>,
+ tag_set: Arc<TagSet<T>>,
gendisk: *mut bindings::gendisk,
backref: Arc<Revocable<GenDiskRef<T>>>,
}
@@ -342,6 +342,11 @@ pub fn queue_data(&self) -> <T::QueueData as ForeignOwnable>::Borrowed<'_> {
// SAFETY: By type invariant, self is a valid gendisk.
unsafe { T::QueueData::borrow((*(*self.gendisk).queue).queuedata) }
}
+
+ /// Get a reference to the `TagSet` used by this `GenDisk`.
+ pub fn tag_set(&self) -> &Arc<TagSet<T>> {
+ &self.tag_set
+ }
}
// SAFETY: `GenDisk` is an owned pointer to a `struct gendisk` and an `Arc` to a
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (60 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 61/79] block: rust: add `GenDisk::tag_set` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-16 23:59 ` Ken Kurematsu
2026-02-15 23:35 ` [PATCH 63/79] block: rnull: add an option to change the number of hardware queues Andreas Hindborg
` (16 subsequent siblings)
78 siblings, 1 reply; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method to `TagSet` that allows changing the number of hardware queues
dynamically.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/tag_set.rs | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index 4d00979a83dbd..47a162360e628 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -8,6 +8,7 @@
bindings,
block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations},
error::{self, Result},
+ prelude::*,
try_pin_init,
types::{ForeignOwnable, Opaque},
};
@@ -34,7 +35,7 @@ pub struct TagSet<T: Operations> {
}
impl<T: Operations> TagSet<T> {
- /// Try to create a new tag set
+ /// Try to create a new tag se }t
pub fn new(
nr_hw_queues: u32,
tagset_data: T::TagSetData,
@@ -142,6 +143,20 @@ pub fn hw_queue_count(&self) -> u32 {
unsafe { (*self.inner.get()).nr_hw_queues }
}
+ /// Update the number of hardware queues for this tag set.
+ ///
+ /// This operation may fail if memory for tags cannot be allocated.
+ pub fn update_hw_queue_count(&self, nr_hw_queues: u32) -> Result {
+ // SAFETY: blk_mq_update_nr_hw_queues applies internal synchronization.
+ unsafe { bindings::blk_mq_update_nr_hw_queues(self.inner.get(), nr_hw_queues) }
+
+ if self.hw_queue_count() == nr_hw_queues {
+ Ok(())
+ } else {
+ Err(ENOMEM)
+ }
+ }
+
/// Borrow the [`T::TagSetData`] associated with this tag set.
pub fn data(&self) -> <T::TagSetData as ForeignOwnable>::Borrowed<'_> {
// SAFETY: By type invariant, `self.inner` is valid.
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* RE: [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count`
2026-02-15 23:35 ` [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count` Andreas Hindborg
@ 2026-02-16 23:59 ` Ken Kurematsu
2026-02-17 9:54 ` Andreas Hindborg
0 siblings, 1 reply; 114+ messages in thread
From: Ken Kurematsu @ 2026-02-16 23:59 UTC (permalink / raw)
To: Andreas Hindborg, Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ken Kurematsu
Hi Andreas,
> -----Original Message-----
> From: Andreas Hindborg <a.hindborg@kernel.org>
> Sent: Monday, February 16, 2026 8:36 AM
> To: Boqun Feng <boqun.feng@gmail.com>; Jens Axboe <axboe@kernel.dk>;
> Miguel Ojeda <ojeda@kernel.org>; Gary Guo <gary@garyguo.net>; Björn Roy
> Baron <bjorn3_gh@protonmail.com>; Benno Lossin <lossin@kernel.org>;
> Alice Ryhl <aliceryhl@google.com>; Trevor Gross <tmgross@umich.edu>;
> Danilo Krummrich <dakr@kernel.org>; FUJITA Tomonori
> <fujita.tomonori@gmail.com>; Frederic Weisbecker <frederic@kernel.org>;
> Lyude Paul <lyude@redhat.com>; Thomas Gleixner <tglx@kernel.org>;
> Anna-Maria Behnsen <anna-maria@linutronix.de>; John Stultz
> <jstultz@google.com>; Stephen Boyd <sboyd@kernel.org>; Lorenzo Stoakes
> <lorenzo.stoakes@oracle.com>; Liam R. Howlett
> <Liam.Howlett@oracle.com>
> Cc: linux-block@vger.kernel.org; rust-for-linux@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-mm@kvack.org; Andreas Hindborg
> <a.hindborg@kernel.org>
> Subject: [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count`
>
> Add a method to `TagSet` that allows changing the number of hardware
> queues
> dynamically.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
> ---
> rust/kernel/block/mq/tag_set.rs | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/rust/kernel/block/mq/tag_set.rs
> b/rust/kernel/block/mq/tag_set.rs
> index 4d00979a83dbd..47a162360e628 100644
> --- a/rust/kernel/block/mq/tag_set.rs
> +++ b/rust/kernel/block/mq/tag_set.rs
> @@ -8,6 +8,7 @@
> bindings,
> block::mq::{operations::OperationsVTable, request::RequestDataWrapper,
> Operations},
> error::{self, Result},
> + prelude::*,
> try_pin_init,
> types::{ForeignOwnable, Opaque},
> };
> @@ -34,7 +35,7 @@ pub struct TagSet<T: Operations> {
> }
>
> impl<T: Operations> TagSet<T> {
> - /// Try to create a new tag set
> + /// Try to create a new tag se }t
Is this a typo?
It looks like an unnecessary ' }'.
> pub fn new(
> nr_hw_queues: u32,
> tagset_data: T::TagSetData,
> @@ -142,6 +143,20 @@ pub fn hw_queue_count(&self) -> u32 {
> unsafe { (*self.inner.get()).nr_hw_queues }
> }
>
> + /// Update the number of hardware queues for this tag set.
> + ///
> + /// This operation may fail if memory for tags cannot be allocated.
> + pub fn update_hw_queue_count(&self, nr_hw_queues: u32) -> Result {
> + // SAFETY: blk_mq_update_nr_hw_queues applies internal
> synchronization.
> + unsafe { bindings::blk_mq_update_nr_hw_queues(self.inner.get(),
> nr_hw_queues) }
> +
> + if self.hw_queue_count() == nr_hw_queues {
> + Ok(())
> + } else {
> + Err(ENOMEM)
> + }
> + }
> +
> /// Borrow the [`T::TagSetData`] associated with this tag set.
> pub fn data(&self) -> <T::TagSetData as
> ForeignOwnable>::Borrowed<'_> {
> // SAFETY: By type invariant, `self.inner` is valid.
>
> --
> 2.51.2
>
>
Best regards,
Ken Kurematsu
^ permalink raw reply [flat|nested] 114+ messages in thread* RE: [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count`
2026-02-16 23:59 ` Ken Kurematsu
@ 2026-02-17 9:54 ` Andreas Hindborg
0 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-17 9:54 UTC (permalink / raw)
To: Ken Kurematsu, Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ken Kurematsu
"Ken Kurematsu" <k.kurematsu@nskint.co.jp> writes:
> Hi Andreas,
>
>> -----Original Message-----
>> From: Andreas Hindborg <a.hindborg@kernel.org>
>> Sent: Monday, February 16, 2026 8:36 AM
>> To: Boqun Feng <boqun.feng@gmail.com>; Jens Axboe <axboe@kernel.dk>;
>> Miguel Ojeda <ojeda@kernel.org>; Gary Guo <gary@garyguo.net>; Björn Roy
>> Baron <bjorn3_gh@protonmail.com>; Benno Lossin <lossin@kernel.org>;
>> Alice Ryhl <aliceryhl@google.com>; Trevor Gross <tmgross@umich.edu>;
>> Danilo Krummrich <dakr@kernel.org>; FUJITA Tomonori
>> <fujita.tomonori@gmail.com>; Frederic Weisbecker <frederic@kernel.org>;
>> Lyude Paul <lyude@redhat.com>; Thomas Gleixner <tglx@kernel.org>;
>> Anna-Maria Behnsen <anna-maria@linutronix.de>; John Stultz
>> <jstultz@google.com>; Stephen Boyd <sboyd@kernel.org>; Lorenzo Stoakes
>> <lorenzo.stoakes@oracle.com>; Liam R. Howlett
>> <Liam.Howlett@oracle.com>
>> Cc: linux-block@vger.kernel.org; rust-for-linux@vger.kernel.org;
>> linux-kernel@vger.kernel.org; linux-mm@kvack.org; Andreas Hindborg
>> <a.hindborg@kernel.org>
>> Subject: [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count`
>>
>> Add a method to `TagSet` that allows changing the number of hardware
>> queues
>> dynamically.
>>
>> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
>> ---
>> rust/kernel/block/mq/tag_set.rs | 17 ++++++++++++++++-
>> 1 file changed, 16 insertions(+), 1 deletion(-)
>>
>> diff --git a/rust/kernel/block/mq/tag_set.rs
>> b/rust/kernel/block/mq/tag_set.rs
>> index 4d00979a83dbd..47a162360e628 100644
>> --- a/rust/kernel/block/mq/tag_set.rs
>> +++ b/rust/kernel/block/mq/tag_set.rs
>> @@ -8,6 +8,7 @@
>> bindings,
>> block::mq::{operations::OperationsVTable, request::RequestDataWrapper,
>> Operations},
>> error::{self, Result},
>> + prelude::*,
>> try_pin_init,
>> types::{ForeignOwnable, Opaque},
>> };
>> @@ -34,7 +35,7 @@ pub struct TagSet<T: Operations> {
>> }
>>
>> impl<T: Operations> TagSet<T> {
>> - /// Try to create a new tag set
>> + /// Try to create a new tag se }t
>
> Is this a typo?
> It looks like an unnecessary ' }'.
Yes, that is a mistake. Thanks!
Best regards,
Andreas Hindborg
^ permalink raw reply [flat|nested] 114+ messages in thread
* [PATCH 63/79] block: rnull: add an option to change the number of hardware queues
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (61 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 62/79] block: rust: add `TagSet::update_hw_queue_count` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 64/79] block: rust: add an abstraction for `struct rq_list` Andreas Hindborg
` (15 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a feature to rnull that allows changing the number of simulated
hardware queues during device operation.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 143 +++++++++++++++++++++++++---------------
drivers/block/rnull/rnull.rs | 39 +++++++----
2 files changed, 116 insertions(+), 66 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 816c057f130fc..424722f01ab8d 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -138,7 +138,13 @@ fn make_group(
completion_time: time::Delta::ZERO,
name: name.try_into()?,
memory_backed: false,
- submit_queues: 1,
+ queue_config: Arc::pin_init(
+ new_mutex!(QueueConfig {
+ submit_queues: 1,
+ poll_queues: 0
+ }),
+ GFP_KERNEL
+ )?,
home_node: bindings::NUMA_NO_NODE,
discard: false,
no_sched: false,
@@ -158,7 +164,6 @@ fn make_group(
zone_max_open: 0,
zone_max_active: 0,
zone_append_max_sectors: u32::MAX,
- poll_queues: 0,
fua: true,
}),
}),
@@ -215,7 +220,7 @@ struct DeviceConfigInner {
completion_time: time::Delta,
disk: Option<Arc<GenDisk<NullBlkDevice>>>,
memory_backed: bool,
- submit_queues: u32,
+ queue_config: Arc<Mutex<QueueConfig>>,
home_node: i32,
discard: bool,
no_sched: bool,
@@ -235,7 +240,6 @@ struct DeviceConfigInner {
zone_max_open: u32,
zone_max_active: u32,
zone_append_max_sectors: u32,
- poll_queues: u32,
fua: bool,
}
@@ -268,7 +272,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
irq_mode: guard.irq_mode,
completion_time: guard.completion_time,
memory_backed: guard.memory_backed,
- submit_queues: guard.submit_queues,
+ queue_config: guard.queue_config.clone(),
home_node: guard.home_node,
discard: guard.discard,
no_sched: guard.no_sched,
@@ -287,7 +291,6 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
zone_max_open: guard.zone_max_open,
zone_max_active: guard.zone_max_active,
zone_append_max_sectors: guard.zone_append_max_sectors,
- poll_queues: guard.poll_queues,
forced_unit_access: guard.fua,
})?);
guard.powered = true;
@@ -300,9 +303,17 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
-configfs_simple_field!(DeviceConfig, 1,
- block_size, u32,
- check GenDiskBuilder::<NullBlkDevice>::validate_block_size
+pub(crate) struct QueueConfig {
+ pub(crate) submit_queues: u32,
+ pub(crate) poll_queues: u32,
+}
+
+configfs_simple_field!(
+ DeviceConfig,
+ 1,
+ block_size,
+ u32,
+ check GenDiskBuilder::<NullBlkDevice>::validate_block_size
);
configfs_simple_bool_field!(DeviceConfig, 2, rotational);
configfs_simple_field!(DeviceConfig, 3, capacity_mib, u64);
@@ -349,51 +360,57 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
}
-#[vtable]
-impl configfs::AttributeOperations<7> for DeviceConfig {
- type Data = DeviceConfig;
-
- fn show(this: &DeviceConfig, page: &mut [u8; PAGE_SIZE]) -> Result<usize> {
- let mut writer = kernel::str::Formatter::new(page);
- writer.write_fmt(fmt!("{}\n", this.data.lock().submit_queues))?;
- Ok(writer.bytes_written())
- }
+configfs_attribute! {
+ DeviceConfig,
+ 7,
+ show: |this, page| show_field(this.data.lock().queue_config.lock().submit_queues, page),
+ store: |this,page| {
+ let config_guard = this.data.lock();
+ let mut queue_config = config_guard.queue_config.lock();
- fn store(this: &DeviceConfig, page: &[u8]) -> Result {
- if this.data.lock().powered {
- return Err(EBUSY);
+ let text = core::str::from_utf8(page)?.trim();
+ let value = text.parse().map_err(|_| EINVAL)?;
+ if value > kernel::num_possible_cpus() {
+ return Err(kernel::error::code::EINVAL)
}
- let text = core::str::from_utf8(page)?.trim();
- let value = text
- .parse::<u32>()
- .map_err(|_| kernel::error::code::EINVAL)?;
+ let old_submit_queues = queue_config.submit_queues;
+ queue_config.submit_queues = value;
+ let total_queue_count = queue_config.submit_queues + queue_config.poll_queues;
+
+ let disk = config_guard.disk.clone();
+
+ drop(queue_config);
+ drop(config_guard);
- if value == 0 || value > kernel::num_possible_cpus() {
- return Err(kernel::error::code::EINVAL);
+ if let Some(disk) = &disk {
+ if let Err(e) = disk.tag_set().update_hw_queue_count(total_queue_count) {
+ this.data.lock().queue_config.lock().submit_queues = old_submit_queues;
+ return Err(e);
+ }
}
- this.data.lock().submit_queues = value;
Ok(())
- }
+ },
}
configfs_attribute!(DeviceConfig, 8,
- show: |this, page| show_field(
- this.data.lock().submit_queues == kernel::num_online_nodes(), page
- ),
- store: |this, page| store_with_power_check(this, page, |this, page| {
- let value = core::str::from_utf8(page)?
- .trim()
- .parse::<u8>()
- .map_err(|_| kernel::error::code::EINVAL)?
- != 0;
-
- if value {
- this.data.lock().submit_queues *= kernel::num_online_nodes();
- }
- Ok(())
- })
+ show: |this, page| show_field(
+ this.data.lock().queue_config.lock().submit_queues == kernel::num_online_nodes(),
+ page
+ ),
+ store: |this, page| store_with_power_check(this, page, |this, page| {
+ let value = core::str::from_utf8(page)?
+ .trim()
+ .parse::<u8>()
+ .map_err(|_| kernel::error::code::EINVAL)?
+ != 0;
+
+ if value {
+ this.data.lock().queue_config.lock().submit_queues *= kernel::num_online_nodes();
+ }
+ Ok(())
+ })
);
configfs_simple_field!(
@@ -518,17 +535,37 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_field!(DeviceConfig, 24, zone_max_open, u32);
configfs_simple_field!(DeviceConfig, 25, zone_max_active, u32);
configfs_simple_field!(DeviceConfig, 26, zone_append_max_sectors, u32);
-configfs_simple_field!(
+configfs_attribute! {
DeviceConfig,
27,
- poll_queues,
- u32,
- check | value | {
+ show: |this, page| show_field(this.data.lock().queue_config.lock().poll_queues, page),
+ store: |this,page| {
+ let config_guard = this.data.lock();
+ let mut queue_config = config_guard.queue_config.lock();
+
+ let text = core::str::from_utf8(page)?.trim();
+ let value = text.parse().map_err(|_| EINVAL)?;
if value > kernel::num_possible_cpus() {
- Err(kernel::error::code::EINVAL)
- } else {
- Ok(())
+ return Err(kernel::error::code::EINVAL)
}
- }
-);
+
+ let old_poll_queues = queue_config.poll_queues;
+ queue_config.poll_queues = value;
+ let total_queue_count = queue_config.submit_queues + queue_config.poll_queues;
+
+ let disk = config_guard.disk.clone();
+
+ drop(queue_config);
+ drop(config_guard);
+
+ if let Some(disk) = &disk {
+ if let Err(e) = disk.tag_set().update_hw_queue_count(total_queue_count) {
+ this.data.lock().queue_config.lock().poll_queues = old_poll_queues;
+ return Err(e);
+ }
+ }
+
+ Ok(())
+ },
+}
configfs_simple_bool_field!(DeviceConfig, 28, fua);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 3b7edfe7efe44..429819bf042ba 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -10,7 +10,10 @@
#[cfg(CONFIG_BLK_DEV_ZONED)]
mod zoned;
-use configfs::IRQMode;
+use configfs::{
+ IRQMode,
+ QueueConfig, //
+};
use disk_storage::{
DiskStorage,
NullBlockPage,
@@ -225,6 +228,8 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
*module_parameters::submit_queues.value()
};
+ let poll_queues = *module_parameters::poll_queues.value();
+
let block_size = *module_parameters::bs.value();
let disk = NullBlkDevice::new(NullBlkOptions {
name: &name,
@@ -234,7 +239,13 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
irq_mode: (*module_parameters::irqmode.value()).try_into()?,
completion_time: Delta::from_nanos(completion_time),
memory_backed: *module_parameters::memory_backed.value() != 0,
- submit_queues,
+ queue_config: Arc::pin_init(
+ new_mutex!(QueueConfig {
+ submit_queues,
+ poll_queues
+ }),
+ GFP_KERNEL,
+ )?,
home_node: *module_parameters::home_node.value(),
discard: *module_parameters::discard.value() != 0,
no_sched: *module_parameters::no_sched.value() != 0,
@@ -253,7 +264,6 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
zone_max_open: *module_parameters::zone_max_open.value(),
zone_max_active: *module_parameters::zone_max_active.value(),
zone_append_max_sectors: *module_parameters::zone_append_max_sectors.value(),
- poll_queues: *module_parameters::poll_queues.value(),
forced_unit_access: *module_parameters::fua.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
@@ -277,7 +287,7 @@ struct NullBlkOptions<'a> {
irq_mode: IRQMode,
completion_time: Delta,
memory_backed: bool,
- submit_queues: u32,
+ queue_config: Arc<Mutex<QueueConfig>>,
home_node: i32,
discard: bool,
no_sched: bool,
@@ -302,7 +312,6 @@ struct NullBlkOptions<'a> {
zone_max_active: u32,
#[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
zone_append_max_sectors: u32,
- poll_queues: u32,
forced_unit_access: bool,
}
@@ -342,7 +351,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
irq_mode,
completion_time,
memory_backed,
- submit_queues,
+ queue_config,
home_node,
discard,
no_sched,
@@ -361,7 +370,6 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
zone_max_open,
zone_max_active,
zone_append_max_sectors,
- poll_queues,
forced_unit_access,
} = options;
@@ -379,6 +387,11 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
return Err(code::EINVAL);
}
+ let queue_config_guard = queue_config.lock();
+ let submit_queues = queue_config_guard.submit_queues;
+ let poll_queues = queue_config_guard.poll_queues;
+ drop(queue_config_guard);
+
let tagset_ctor = || -> Result<Arc<_>> {
Arc::pin_init(
TagSet::new(
@@ -386,8 +399,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
KBox::new(
NullBlkTagsetData {
queue_depth: hw_queue_depth,
- submit_queue_count: submit_queues,
- poll_queue_count: poll_queues,
+ queue_config,
},
GFP_KERNEL,
)?,
@@ -773,8 +785,7 @@ impl HasHrTimer<Self> for Pdu {
struct NullBlkTagsetData {
queue_depth: u32,
- submit_queue_count: u32,
- poll_queue_count: u32,
+ queue_config: Arc<Mutex<QueueConfig>>,
}
#[vtable]
@@ -919,8 +930,10 @@ fn report_zones(
}
fn map_queues(tag_set: Pin<&mut TagSet<Self>>) {
- let mut submit_queue_count = tag_set.data().submit_queue_count;
- let mut poll_queue_count = tag_set.data().poll_queue_count;
+ let queue_config = tag_set.data().queue_config.lock();
+ let mut submit_queue_count = queue_config.submit_queues;
+ let mut poll_queue_count = queue_config.poll_queues;
+ drop(queue_config);
if tag_set.hw_queue_count() != submit_queue_count + poll_queue_count {
pr_warn!(
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 64/79] block: rust: add an abstraction for `struct rq_list`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (62 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 63/79] block: rnull: add an option to change the number of hardware queues Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 65/79] block: rust: add `queue_rqs` vtable hook Andreas Hindborg
` (14 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add the `RequestList` type as a safe wrapper around the C `struct
rq_list`. This type provides methods to iterate over and manipulate
lists of block requests, which is needed for implementing the
`queue_rqs` callback.
The abstraction includes methods for popping requests from the list,
checking if the list is empty, and peeking at the head request.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/helpers/blk.c | 26 ++++++++
rust/kernel/block/mq.rs | 2 +
rust/kernel/block/mq/request_list.rs | 113 +++++++++++++++++++++++++++++++++++
3 files changed, 141 insertions(+)
diff --git a/rust/helpers/blk.c b/rust/helpers/blk.c
index 91b72131a04cd..0db567dfc5d53 100644
--- a/rust/helpers/blk.c
+++ b/rust/helpers/blk.c
@@ -27,3 +27,29 @@ bool rust_helper_blk_mq_add_to_batch(struct request *req,
{
return blk_mq_add_to_batch(req, iob, is_error, complete);
}
+
+__rust_helper struct request *rust_helper_rq_list_pop(struct rq_list *rl)
+{
+ return rq_list_pop(rl);
+}
+
+__rust_helper int rust_helper_rq_list_empty(const struct rq_list *rl)
+{
+ return rq_list_empty(rl);
+}
+
+__rust_helper void rust_helper_rq_list_add_tail(struct rq_list *rl,
+ struct request *rq)
+{
+ rq_list_add_tail(rl, rq);
+}
+
+__rust_helper void rust_helper_rq_list_init(struct rq_list *rl)
+{
+ rq_list_init(rl);
+}
+
+__rust_helper struct request *rust_helper_rq_list_peek(struct rq_list *rl)
+{
+ return rq_list_peek(rl);
+}
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index b36112f7b22b9..786c32f2cb56c 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -129,6 +129,7 @@
pub mod gen_disk;
mod operations;
mod request;
+mod request_list;
mod request_queue;
pub mod tag_set;
@@ -141,6 +142,7 @@
pub use request::IdleRequest;
pub use request::Request;
pub use request::RequestTimerHandle;
+pub use request_list::RequestList;
pub use request_queue::RequestQueue;
pub use tag_set::QueueType;
pub use tag_set::TagSet;
diff --git a/rust/kernel/block/mq/request_list.rs b/rust/kernel/block/mq/request_list.rs
new file mode 100644
index 0000000000000..60284d9ef6c9c
--- /dev/null
+++ b/rust/kernel/block/mq/request_list.rs
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::marker::PhantomData;
+
+use crate::{owned::Owned, types::Opaque};
+
+use super::{IdleRequest, Operations};
+
+/// A list of [`Request`].
+///
+/// # INVARIANTS
+///
+/// - `self.inner` is always a valid list, meaning the `next` and `prev`
+/// pointers point to valid requests, or are both null.
+/// - All requests in the list are valid for use as `IdleRequest<T>`.
+#[repr(transparent)]
+pub struct RequestList<T: Operations> {
+ inner: Opaque<bindings::rq_list>,
+ _p: PhantomData<T>,
+}
+
+impl<T: Operations> RequestList<T> {
+ /// Create a new [`RequestList`].
+ pub fn new() -> Self {
+ let this = Self {
+ inner: Opaque::zeroed(),
+ _p: PhantomData,
+ };
+
+ // NOTE: We are actually good to go, but we call the C initializer for forward
+ // compatibility.
+ // SAFETY: `this.inner` is a valid allocation for use as `bindings::rq_list!.
+ unsafe { bindings::rq_list_init(this.inner.get()) }
+
+ //INVARIANT: `self.inner` was initialized above and is empty.
+ this
+ }
+
+ /// Create a mutable reference to a [`RequestList`] from a raw pointer.
+ ///
+ /// # SAFETY
+ /// - The list pointed to by `ptr` must satisfy the invariants of `Self`.
+ /// - The list pointed to by `ptr` must remain valid for use as a mutable reference for the
+ /// duration of `'a`.
+ pub unsafe fn from_raw<'a>(ptr: *mut bindings::rq_list) -> &'a mut Self {
+ // SAFETY:
+ // - RequestList is transparent.
+ // - By function safety requirements, `ptr` is valid for us as a mutable reference.
+ unsafe { &mut (*ptr.cast()) }
+ }
+
+ /// Check if the list is empty.
+ pub fn empty(&self) -> bool {
+ // SAFETY: By type invariant, self.inner is valid.
+ let ret = unsafe { bindings::rq_list_empty(self.inner.get()) };
+ ret != 0
+ }
+
+ /// Pop a request from the list.
+ ///
+ /// Returns [`None`] if the list is empty.
+ pub fn pop(&mut self) -> Option<Owned<IdleRequest<T>>> {
+ // SAFETY: By type invariant `self.inner` is a valid list.
+ let ptr = unsafe { bindings::rq_list_pop(self.inner.get()) };
+
+ if !ptr.is_null() {
+ // SAFETY: If `rq_list_pop` returns a non-null pointer, it points to a valid request. By
+ // type invariant all requests in this list are valid for use as `IdleRequest`.
+ Some(unsafe { IdleRequest::from_raw(ptr) })
+ } else {
+ None
+ }
+ }
+
+ /// Push a request on the tail of the list.
+ pub fn push_tail(&mut self, rq: Owned<IdleRequest<T>>) {
+ let ptr = rq.as_raw();
+ core::mem::forget(rq);
+ // INVARIANT: rq is an `IdleRequest<T>`.
+ // SAFETY: By type invariant, `self.inner` is a valid list.
+ unsafe { bindings::rq_list_add_tail(self.inner.get(), ptr) };
+ }
+
+ /// Peek at the head of the list.
+ ///
+ /// Returns a null pointer if the list is empty.
+ pub fn peek_raw(&self) -> *mut bindings::request {
+ // SAFETY: By type invariant, `self.inner` is a valid list.
+ unsafe { bindings::rq_list_peek(self.inner.get()) }
+ }
+}
+
+impl<T: Operations> Default for RequestList<T> {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<T: Operations> Drop for RequestList<T> {
+ fn drop(&mut self) {
+ while let Some(rq) = self.pop() {
+ drop(rq)
+ }
+ }
+}
+
+impl<T: Operations> Iterator for &mut RequestList<T> {
+ type Item = Owned<IdleRequest<T>>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.pop()
+ }
+}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 65/79] block: rust: add `queue_rqs` vtable hook
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (63 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 64/79] block: rust: add an abstraction for `struct rq_list` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 66/79] block: rnull: support queue_rqs Andreas Hindborg
` (13 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add support for the `queue_rqs` callback to the Rust block layer
bindings. This callback allows drivers to receive multiple requests in
a single call, enabling batch processing optimizations.
The callback receives a `RequestList` containing the requests to be
processed. Drivers should remove successfully processed requests from
the list; any remaining requests will be requeued individually.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/operations.rs | 61 +++++++++++++++++++++++++++++++++++++-
rust/kernel/block/mq/request.rs | 26 ++++++++++++++++
2 files changed, 86 insertions(+), 1 deletion(-)
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index bccc1903a0d10..e4de6db807e18 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -18,6 +18,8 @@
use core::{marker::PhantomData, ptr::NonNull};
use pin_init::PinInit;
+use super::request_list::RequestList;
+
type ForeignBorrowed<'a, T> = <T as ForeignOwnable>::Borrowed<'a>;
/// Implement this trait to interface blk-mq as block devices.
@@ -68,6 +70,15 @@ fn queue_rq(
is_poll: bool,
) -> BlkResult;
+ /// Called by the kernel to queue a list of requests with the driver.
+ fn queue_rqs(
+ _hw_data: ForeignBorrowed<'_, Self::HwData>,
+ _queue_data: ForeignBorrowed<'_, Self::QueueData>,
+ _requests: &mut RequestList<Self>,
+ ) {
+ build_error!(crate::error::VTABLE_DEFAULT_ERROR)
+ }
+
/// Called by the kernel to indicate that queued requests should be submitted.
fn commit_rqs(
hw_data: ForeignBorrowed<'_, Self::HwData>,
@@ -208,6 +219,50 @@ impl<T: Operations> OperationsVTable<T> {
}
}
+ /// This function is called by the C kernel to queue a list of new requests.
+ ///
+ /// Driver is guaranteed that each request belongs to the same queue. If the
+ /// driver doesn't empty the `rqlist` completely, then the rest will be
+ /// queued individually by the block layer upon return.
+ ///
+ /// # SAFETY
+ ///
+ /// - `requests` must satisfy the safety requirements of `RequestList<T>`
+ /// - All requests in `requests` must belong to the same hardware context.
+ unsafe extern "C" fn queue_rqs_callback(requests: *mut bindings::rq_list) {
+ // SAFETY:
+ // - By the safety requirements of this function, `requests` is valid for use as a
+ // `RequestList`.
+ // - We have exclusive access to `requests` for the duration of this function.
+ let requests = unsafe { RequestList::from_raw(requests) };
+
+ let rq_ptr = requests.peek_raw();
+
+ if rq_ptr.is_null() {
+ return;
+ }
+
+ // SAFETY: By function safety requirements, rq_ptr is pointing to a
+ // valid request.
+ let hctx = unsafe { (*rq_ptr).mq_hctx };
+
+ // SAFETY: The safety requirement for this function ensure that `hctx`
+ // is valid and that `driver_data` was produced by a call to
+ // `into_foreign` in `Self::init_hctx_callback`.
+ let hw_data = unsafe { T::HwData::borrow((*hctx).driver_data) };
+
+ // SAFETY: `hctx` is valid as required by this function.
+ let queue_data = unsafe { (*(*hctx).queue).queuedata };
+
+ // SAFETY: `queue.queuedata` was created by `GenDiskBuilder::build` with
+ // a call to `ForeignOwnable::into_foreign` to create `queuedata`.
+ // `ForeignOwnable::from_foreign` is only called when the tagset is
+ // dropped, which happens after we are dropped.
+ let queue_data = unsafe { T::QueueData::borrow(queue_data) };
+
+ T::queue_rqs(hw_data, queue_data, requests);
+ }
+
/// This function is called by the C kernel. A pointer to this function is
/// installed in the `blk_mq_ops` vtable for the driver.
///
@@ -450,7 +505,11 @@ impl<T: Operations> OperationsVTable<T> {
const VTABLE: bindings::blk_mq_ops = bindings::blk_mq_ops {
queue_rq: Some(Self::queue_rq_callback),
- queue_rqs: None,
+ queue_rqs: if T::HAS_QUEUE_RQS {
+ Some(Self::queue_rqs_callback)
+ } else {
+ None
+ },
commit_rqs: Some(Self::commit_rqs_callback),
get_budget: None,
put_budget: None,
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index bc655d202ca01..e22af7ea77bbc 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -148,6 +148,32 @@ pub fn queue(&self) -> &RequestQueue<T> {
pub fn as_raw(&self) -> *mut bindings::request {
self.0.get()
}
+
+ // Return a valid hctx pointer.
+ fn hctx_raw(&self) -> *mut bindings::blk_mq_hw_ctx {
+ // SAFETY: The requests is guaranteed to be associated with a hardware
+ // context while we have access to it.
+ unsafe { (*self.0.get()).mq_hctx }
+ }
+
+ /// Get a reference to the [`T::HwData`] for the hardware context that this
+ /// request is associated with.
+ pub fn hw_data(&self) -> <T::HwData as ForeignOwnable>::Borrowed<'_> {
+ let hctx = self.hctx_raw();
+
+ // SAFETY: `hctx` is valid and `driver_data` was produced by a call to
+ // `into_foreign` in `Operations::init_hctx_callback`.
+ unsafe { T::HwData::borrow((*hctx).driver_data) }
+ }
+
+ pub fn is_poll(&self) -> bool {
+ let hctx = self.hctx_raw();
+
+ u32::from(
+ // SAFETY: `hctx_raw` returns a valid pointer.
+ unsafe { (*hctx).type_ },
+ ) == bindings::hctx_type_HCTX_TYPE_POLL
+ }
}
/// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 66/79] block: rnull: support queue_rqs
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (64 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 65/79] block: rust: add `queue_rqs` vtable hook Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 67/79] block: rust: remove the `is_poll` parameter from `queue_rq` Andreas Hindborg
` (12 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Implement the `queue_rqs` callback for rnull, allowing the block layer
to submit multiple requests in a single call. This improves performance
by reducing per-request overhead and enabling batch processing.
The implementation processes requests from the list one at a time,
removing successfully processed requests from the list.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/disk_storage.rs | 34 +++----
drivers/block/rnull/rnull.rs | 180 +++++++++++++++++++++++-------------
2 files changed, 132 insertions(+), 82 deletions(-)
diff --git a/drivers/block/rnull/disk_storage.rs b/drivers/block/rnull/disk_storage.rs
index b2b5eaa783cdc..d9f2703957fc0 100644
--- a/drivers/block/rnull/disk_storage.rs
+++ b/drivers/block/rnull/disk_storage.rs
@@ -86,7 +86,7 @@ pub(crate) fn discard(
}
}
- pub(crate) fn flush(&self, hw_data: &Pin<&SpinLock<HwQueueContext>>) -> Result {
+ pub(crate) fn flush(&self, hw_data: &Pin<&SpinLock<HwQueueContext>>) {
let mut tree_guard = self.lock();
let mut hw_data_guard = hw_data.lock();
let mut access = self.access(&mut tree_guard, &mut hw_data_guard, None);
@@ -129,16 +129,10 @@ fn to_sector(index: usize) -> u64 {
(index << block::PAGE_SECTORS_SHIFT) as u64
}
- fn extract_cache_page(&mut self) -> Result<Option<KBox<NullBlockPage>>> {
+ fn extract_cache_page(&mut self) -> Option<KBox<NullBlockPage>> {
let cache_entry = self.cache_guard.find_next_entry_circular(
self.disk_storage.next_flush_sector.load(ordering::Relaxed) as usize,
- );
-
- let cache_entry = if let Some(entry) = cache_entry {
- entry
- } else {
- return Ok(None);
- };
+ )?;
let index = cache_entry.index();
@@ -168,11 +162,14 @@ fn extract_cache_page(&mut self) -> Result<Option<KBox<NullBlockPage>>> {
let mut src = cache_entry;
let mut offset = 0;
for _ in 0..PAGE_SECTORS {
- src.page_mut().get_pin_mut().copy_to_page(
- disk_entry.page_mut().get_pin_mut(),
- offset,
- block::SECTOR_SIZE as usize,
- )?;
+ src.page_mut()
+ .get_pin_mut()
+ .copy_to_page(
+ disk_entry.page_mut().get_pin_mut(),
+ offset,
+ block::SECTOR_SIZE as usize,
+ )
+ .expect("Write to succeed");
offset += block::SECTOR_SIZE as usize;
}
src.remove()
@@ -182,16 +179,15 @@ fn extract_cache_page(&mut self) -> Result<Option<KBox<NullBlockPage>>> {
}
};
- Ok(Some(page))
+ Some(page)
}
- fn flush(&mut self) -> Result {
+ fn flush(&mut self) {
if self.disk_storage.cache_size > 0 {
- while let Some(page) = self.extract_cache_page()? {
+ while let Some(page) = self.extract_cache_page() {
drop(page);
}
}
- Ok(())
}
fn get_or_alloc_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage> {
@@ -208,7 +204,7 @@ fn get_or_alloc_cache_page(&mut self, sector: u64) -> Result<&mut NullBlockPage>
.take()
.expect("Expected to have a page available")
} else {
- self.extract_cache_page()?
+ self.extract_cache_page()
.expect("Expected to find a page in the cache")
};
Ok(self
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 429819bf042ba..592fbf5790fd2 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -28,7 +28,7 @@
BadBlocks, //
},
bio::Segment,
- error::BlkResult,
+ error::{BlkError, BlkResult},
mq::{
self,
gen_disk::{
@@ -36,8 +36,10 @@
GenDisk,
GenDiskRef, //
},
+ IdleRequest,
IoCompletionBatch,
Operations,
+ RequestList,
TagSet, //
},
SECTOR_SHIFT,
@@ -720,6 +722,104 @@ fn complete_request(&self, rq: Owned<mq::Request<Self>>) {
}
}
}
+
+ #[inline(always)]
+ fn queue_rq_internal(
+ hw_data: Pin<&SpinLock<HwQueueContext>>,
+ this: ArcBorrow<'_, Self>,
+ rq: Owned<mq::IdleRequest<Self>>,
+ _is_last: bool,
+ ) -> Result<(), QueueRequestError> {
+ if this.bandwidth_limit != 0 {
+ if !this.bandwidth_timer.active() {
+ drop(this.bandwidth_timer_handle.lock().take());
+ let arc: Arc<_> = this.into();
+ *this.bandwidth_timer_handle.lock() =
+ Some(arc.start(Self::BANDWIDTH_TIMER_INTERVAL));
+ }
+
+ if this
+ .bandwidth_bytes
+ .fetch_add(u64::from(rq.bytes()), ordering::Relaxed)
+ + u64::from(rq.bytes())
+ > this.bandwidth_limit
+ {
+ rq.queue().stop_hw_queues();
+ if this.bandwidth_bytes.load(ordering::Relaxed) <= this.bandwidth_limit {
+ rq.queue().start_stopped_hw_queues_async();
+ }
+
+ return Err(QueueRequestError { request: rq });
+ }
+ }
+
+ let mut rq = rq.start();
+
+ if rq.command() == mq::Command::Flush {
+ if this.memory_backed {
+ this.storage.flush(&hw_data);
+ }
+ this.complete_request(rq);
+
+ return Ok(());
+ }
+
+ let status = (|| -> Result {
+ #[cfg(CONFIG_BLK_DEV_ZONED)]
+ if this.zoned.enabled {
+ this.handle_zoned_command(&hw_data, &mut rq)?;
+ } else {
+ this.handle_regular_command(&hw_data, &mut rq)?;
+ }
+
+ #[cfg(not(CONFIG_BLK_DEV_ZONED))]
+ this.handle_regular_command(&hw_data, &mut rq)?;
+
+ Ok(())
+ })();
+
+ if let Err(e) = status {
+ // Do not overwrite existing error. We do not care whether this write fails.
+ let _ = rq
+ .data_ref()
+ .error
+ .cmpxchg(0, e.to_errno(), ordering::Relaxed);
+ }
+
+ if rq.is_poll() {
+ // NOTE: We lack the ability to insert `Owned<Request>` into a
+ // `kernel::list::List`, so we use a `RingBuffer` instead. The
+ // drawback of this is that we have to allocate the space for the
+ // ring buffer during drive initialization, and we have to hold the
+ // lock protecting the list until we have processed all the requests
+ // in the list. Change to a linked list when the kernel gets this
+ // ability.
+
+ // NOTE: We are processing requests during submit rather than during
+ // poll. This is different from C driver. C driver does processing
+ // during poll.
+
+ hw_data
+ .lock()
+ .poll_queue
+ .push_head(rq)
+ .expect("Buffer is sized to hold all in flight requests");
+ } else {
+ this.complete_request(rq);
+ }
+
+ Ok(())
+ }
+}
+
+struct QueueRequestError {
+ request: Owned<IdleRequest<NullBlkDevice>>,
+}
+
+impl From<QueueRequestError> for BlkError {
+ fn from(_value: QueueRequestError) -> Self {
+ kernel::block::error::code::BLK_STS_IOERR
+ }
}
impl_has_hr_timer! {
@@ -761,7 +861,7 @@ struct HwQueueContext {
struct Pdu {
#[pin]
timer: HrTimer<Self>,
- error: Atomic<u32>,
+ error: Atomic<i32>,
}
impl HrTimerCallback for Pdu {
@@ -802,76 +902,31 @@ fn new_request_data() -> impl PinInit<Self::RequestData> {
})
}
- #[inline(always)]
fn queue_rq(
hw_data: Pin<&SpinLock<HwQueueContext>>,
this: ArcBorrow<'_, Self>,
rq: Owned<mq::IdleRequest<Self>>,
- _is_last: bool,
- is_poll: bool,
+ is_last: bool,
+ _is_poll: bool,
) -> BlkResult {
- if this.bandwidth_limit != 0 {
- if !this.bandwidth_timer.active() {
- drop(this.bandwidth_timer_handle.lock().take());
- let arc: Arc<_> = this.into();
- *this.bandwidth_timer_handle.lock() =
- Some(arc.start(Self::BANDWIDTH_TIMER_INTERVAL));
- }
+ Ok(Self::queue_rq_internal(hw_data, this, rq, is_last)?)
+ }
- if this
- .bandwidth_bytes
- .fetch_add(u64::from(rq.bytes()), ordering::Relaxed)
- + u64::from(rq.bytes())
- > this.bandwidth_limit
+ fn queue_rqs(
+ hw_data: Pin<&SpinLock<HwQueueContext>>,
+ this: ArcBorrow<'_, Self>,
+ requests: &mut RequestList<Self>,
+ ) {
+ let mut requeue = RequestList::new();
+ while let Some(request) = requests.pop() {
+ if let Err(QueueRequestError { request }) =
+ Self::queue_rq_internal(hw_data, this, request, false)
{
- rq.queue().stop_hw_queues();
- if this.bandwidth_bytes.load(ordering::Relaxed) <= this.bandwidth_limit {
- rq.queue().start_stopped_hw_queues_async();
- }
-
- return Err(kernel::block::error::code::BLK_STS_DEV_RESOURCE);
+ requeue.push_tail(request);
}
}
- let mut rq = rq.start();
-
- if rq.command() == mq::Command::Flush {
- if this.memory_backed {
- this.storage.flush(&hw_data)?;
- }
- this.complete_request(rq);
-
- return Ok(());
- }
-
- #[cfg(CONFIG_BLK_DEV_ZONED)]
- if this.zoned.enabled {
- this.handle_zoned_command(&hw_data, &mut rq)?;
- } else {
- this.handle_regular_command(&hw_data, &mut rq)?;
- }
-
- #[cfg(not(CONFIG_BLK_DEV_ZONED))]
- this.handle_regular_command(&hw_data, &mut rq)?;
-
- if is_poll {
- // NOTE: We lack the ability to insert `Owned<Request>` into a
- // `kernel::list::List`, so we use a `RingBuffer` instead. The
- // drawback of this is that we have to allocate the space for the
- // ring buffer during drive initialization, and we have to hold the
- // lock protecting the list until we have processed all the requests
- // in the list. Change to a linked list when the kernel gets this
- // ability.
-
- // NOTE: We are processing requests during submit rather than during
- // poll. This is different from C driver. C driver does processing
- // during poll.
-
- hw_data.lock().poll_queue.push_head(rq)?;
- } else {
- this.complete_request(rq);
- }
- Ok(())
+ drop(core::mem::replace(requests, requeue));
}
fn commit_rqs(_hw_data: Pin<&SpinLock<HwQueueContext>>, _queue_data: ArcBorrow<'_, Self>) {}
@@ -888,7 +943,6 @@ fn poll(
let status = rq.data_ref().error.load(ordering::Relaxed);
rq.data_ref().error.store(0, ordering::Relaxed);
- // TODO: check error handling via status
if let Err(rq) = batch.add_request(rq, status != 0) {
Self::end_request(rq);
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 67/79] block: rust: remove the `is_poll` parameter from `queue_rq`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (65 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 66/79] block: rnull: support queue_rqs Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 68/79] block: rust: add a debug assert for refcounts Andreas Hindborg
` (11 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
The information can now be obtained from `Request::is_poll`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/rnull.rs | 1 -
rust/kernel/block/mq.rs | 1 -
rust/kernel/block/mq/operations.rs | 7 -------
3 files changed, 9 deletions(-)
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 592fbf5790fd2..db856f03b78cb 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -907,7 +907,6 @@ fn queue_rq(
this: ArcBorrow<'_, Self>,
rq: Owned<mq::IdleRequest<Self>>,
is_last: bool,
- _is_poll: bool,
) -> BlkResult {
Ok(Self::queue_rq_internal(hw_data, this, rq, is_last)?)
}
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 786c32f2cb56c..02d75acfddb3b 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -90,7 +90,6 @@
//! _queue_data: (),
//! rq: Owned<IdleRequest<Self>>,
//! _is_last: bool,
-//! is_poll: bool
//! ) -> BlkResult {
//! rq.start().end_ok();
//! Ok(())
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index e4de6db807e18..efead98767196 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -67,7 +67,6 @@ fn queue_rq(
queue_data: ForeignBorrowed<'_, Self::QueueData>,
rq: Owned<IdleRequest<Self>>,
is_last: bool,
- is_poll: bool,
) -> BlkResult;
/// Called by the kernel to queue a list of requests with the driver.
@@ -188,11 +187,6 @@ impl<T: Operations> OperationsVTable<T> {
// `into_foreign` in `Self::init_hctx_callback`.
let hw_data = unsafe { T::HwData::borrow((*hctx).driver_data) };
- let is_poll = u32::from(
- // SAFETY: `hctx` is valid as required by this function.
- unsafe { (*hctx).type_ },
- ) == bindings::hctx_type_HCTX_TYPE_POLL;
-
// SAFETY: `hctx` is valid as required by this function.
let queue_data = unsafe { (*(*hctx).queue).queuedata };
@@ -209,7 +203,6 @@ impl<T: Operations> OperationsVTable<T> {
// SAFETY: `bd` is valid as required by the safety requirement for
// this function.
unsafe { (*bd).last },
- is_poll,
);
if let Err(e) = ret {
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 68/79] block: rust: add a debug assert for refcounts
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (66 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 67/79] block: rust: remove the `is_poll` parameter from `queue_rq` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 69/79] block: rust: add `TagSet::tag_to_rq` Andreas Hindborg
` (10 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a debug assertion in `ARef<Request>::dismiss` to verify that the
request refcount is at least two when an `ARef<Request>` exists. This
helps catch reference counting bugs during development.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index e22af7ea77bbc..9a05bce39c64b 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -579,6 +579,17 @@ pub fn dismiss(mut self) {
// SAFETY: `inner` is valid for reads and writes, is properly aligned and nonnull. We have
// exclusive access to `inner` and we do not access `inner` after this call.
unsafe { core::ptr::drop_in_place(inner) };
+
+ debug_assert!(
+ self.inner
+ .wrapper_ref()
+ .refcount()
+ .as_atomic()
+ .load(ordering::Relaxed)
+ >= 2,
+ "Request refcount must be at least two when an ARef<Request> exist"
+ );
+
core::mem::forget(self);
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 69/79] block: rust: add `TagSet::tag_to_rq`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (67 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 68/79] block: rust: add a debug assert for refcounts Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 70/79] block: rust: add `Request::queue_index` Andreas Hindborg
` (9 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a way for block device drivers to obtain a `Request` from a tag. This
is backed by the C `blk_mq_tag_to_rq` but with added checks to ensure
memory safety.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/helpers/blk.c | 6 ++++
rust/kernel/block/mq/tag_set.rs | 72 ++++++++++++++++++++++++++++++++++++++---
2 files changed, 74 insertions(+), 4 deletions(-)
diff --git a/rust/helpers/blk.c b/rust/helpers/blk.c
index 0db567dfc5d53..bb77af6dca9c8 100644
--- a/rust/helpers/blk.c
+++ b/rust/helpers/blk.c
@@ -53,3 +53,9 @@ __rust_helper struct request *rust_helper_rq_list_peek(struct rq_list *rl)
{
return rq_list_peek(rl);
}
+
+__rust_helper struct request *
+rust_helper_blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
+{
+ return blk_mq_tag_to_rq(tags, tag);
+}
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index 47a162360e628..e7d7217da8922 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -5,12 +5,12 @@
//! C header: [`include/linux/blk-mq.h`](srctree/include/linux/blk-mq.h)
use crate::{
- bindings,
block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations},
error::{self, Result},
- prelude::*,
- try_pin_init,
- types::{ForeignOwnable, Opaque},
+ pr_warn,
+ prelude::{ENOMEM, *},
+ sync::atomic::ordering,
+ types::{ARef, ForeignOwnable, Opaque},
};
use core::{convert::TryInto, marker::PhantomData, pin::Pin};
use pin_init::{pin_data, pinned_drop, PinInit};
@@ -19,6 +19,8 @@
pub use flags::Flag;
pub use flags::Flags;
+use super::Request;
+
/// A wrapper for the C `struct blk_mq_tag_set`.
///
/// `struct blk_mq_tag_set` contains a `struct list_head` and so must be pinned.
@@ -166,6 +168,68 @@ pub fn data(&self) -> <T::TagSetData as ForeignOwnable>::Borrowed<'_> {
// converted back with `from_foreign` while `&self` is live.
unsafe { T::TagSetData::borrow(ptr) }
}
+
+ /// Obtain a shared reference to a request.
+ ///
+ /// This method will hang if the request is not owned by the driver, or if
+ /// the driver holds an [`Ownable<Request>`] reference to the request.
+ pub fn tag_to_rq(&self, qid: u32, tag: u32) -> Option<ARef<Request<T>>> {
+ if qid >= self.hw_queue_count() {
+ // TODO: Use pr_warn_once!
+ pr_warn!("Invalid queue id: {qid}\n");
+ return None;
+ }
+
+ // SAFETY: We checked that `qid` is within bounds.
+ let tags = unsafe { *(*self.inner.get()).tags.add(qid as usize) };
+
+ // SAFETY: We checked `qid` for overflow above, so `tags` is valid.
+ let rq_ptr = unsafe { bindings::blk_mq_tag_to_rq(tags, tag) };
+ if rq_ptr.is_null() {
+ None
+ } else {
+ // SAFETY: if `rq_ptr`is not null, it is a valid request pointer.
+ let refcount_ptr = unsafe {
+ RequestDataWrapper::refcount_ptr(
+ Request::wrapper_ptr(rq_ptr.cast::<Request<T>>()).as_ptr(),
+ )
+ };
+
+ // SAFETY: The refcount was initialized in `init_request_callback` and is never
+ // referenced mutably.
+ let refcount_ref = unsafe { &*refcount_ptr };
+
+ let atomic_ref = refcount_ref.as_atomic();
+
+ // It is possible for an interrupt to arrive faster than the last
+ // change to the refcount, so retry if the refcount is not what we
+ // think it should be.
+ loop {
+ // Load acquire to sync with store release of `Owned<Request>`
+ // being destroyed (prevent mutable access overlapping shared
+ // access).
+ let prev = atomic_ref.load(ordering::Acquire);
+
+ if prev >= 1 {
+ // Store relaxed as no other operations need to happen strictly
+ // before or after the increment.
+ match atomic_ref.cmpxchg(prev, prev + 1, ordering::Relaxed) {
+ Ok(_) => break,
+ // NOTE: We cannot use the load part of a failed cmpxchg as it is always
+ // relaxed.
+ Err(_) => continue,
+ }
+ } else {
+ // We are probably waiting to observe a refcount increment.
+ core::hint::spin_loop();
+ continue;
+ };
+ }
+
+ // SAFETY: We checked above that `rq_ptr` is valid for use as an `ARef`.
+ Some(unsafe { Request::aref_from_raw(rq_ptr) })
+ }
+ }
}
#[pinned_drop]
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 70/79] block: rust: add `Request::queue_index`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (68 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 69/79] block: rust: add `TagSet::tag_to_rq` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 71/79] block: rust: add `Request::requeue` Andreas Hindborg
` (8 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method to query a request about the index for the hardware queue
associated with the request.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 9a05bce39c64b..e2fafe7737379 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -166,6 +166,13 @@ pub fn hw_data(&self) -> <T::HwData as ForeignOwnable>::Borrowed<'_> {
unsafe { T::HwData::borrow((*hctx).driver_data) }
}
+ /// Get the queue index for the hardware queue associated with this request.
+ pub fn queue_index(&self) -> u32 {
+ // SAFETY: The requests is guaranteed to be associated with a hardware
+ // context while we have access to it.
+ unsafe { (*self.hctx_raw()).queue_num }
+ }
+
pub fn is_poll(&self) -> bool {
let hctx = self.hctx_raw();
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 71/79] block: rust: add `Request::requeue`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (69 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 70/79] block: rust: add `Request::queue_index` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:35 ` [PATCH 72/79] block: rust: add `request_timeout` hook Andreas Hindborg
` (7 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a method on `Request` to requeue the request with the block layer.
Drivers can use this method to send a request back to the block layer
without processing the request.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/request.rs | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index e2fafe7737379..af10dcbd3ffd1 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -75,6 +75,18 @@ pub(crate) unsafe fn from_raw(ptr: *mut bindings::request) -> Owned<Self> {
// SAFETY: By function safety requirements, `ptr` is valid for use as an `IdleRequest`.
unsafe { Owned::from_raw(NonNull::<Self>::new_unchecked(ptr.cast())) }
}
+
+ /// Requeue this request at the block layer.
+ ///
+ /// If `kick_requeue_list` is true, this method will schedule processing of
+ /// the requeue list on a workqueue.
+ pub fn requeue(self: Owned<Self>, kick_requeue_list: bool) {
+ let ptr = self.0 .0.get();
+ core::mem::forget(self);
+
+ // SAFETY: By type invariant, the wrapped request is valid.
+ unsafe { bindings::blk_mq_requeue_request(ptr, kick_requeue_list) };
+ }
}
// SAFETY: The `release` implementation leaks the `IdleRequest`, which is a valid state for a
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 72/79] block: rust: add `request_timeout` hook
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (70 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 71/79] block: rust: add `Request::requeue` Andreas Hindborg
@ 2026-02-15 23:35 ` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 73/79] block: rnull: add fault injection support Andreas Hindborg
` (6 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:35 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a hook for the request timeout feature. This allows the kernel to call
into a block device driver when it decides a request has timed out. Rust
block device drivers can now implement `Operations::request_timeout` to
respond to request timeouts.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block.rs | 1 +
rust/kernel/block/mq.rs | 1 +
rust/kernel/block/mq/operations.rs | 78 +++++++++++++++++++++++++++++++++++++-
rust/kernel/block/mq/tag_set.rs | 1 -
4 files changed, 79 insertions(+), 2 deletions(-)
diff --git a/rust/kernel/block.rs b/rust/kernel/block.rs
index 6cd83dc75a5eb..d4f09d6fa9f97 100644
--- a/rust/kernel/block.rs
+++ b/rust/kernel/block.rs
@@ -42,6 +42,7 @@ macro_rules! declare_err {
declare_err!(BLK_STS_NOTSUPP, "Operation not supported.");
declare_err!(BLK_STS_IOERR, "Generic IO error.");
declare_err!(BLK_STS_DEV_RESOURCE, "Device resource busy. Retry later.");
+ declare_err!(BLK_STS_TIMEOUT, "Operation timed out.");
}
/// A wrapper around a 1 byte block layer error code.
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 02d75acfddb3b..41008f9bb32cd 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -135,6 +135,7 @@
pub use feature::{Feature, Features};
pub use operations::IoCompletionBatch;
pub use operations::Operations;
+pub use operations::RequestTimeoutStatus;
pub use request::Command;
pub use request::Flag as RequestFlag;
pub use request::Flags as RequestFlags;
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index efead98767196..4767be3ad2a5a 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -125,6 +125,51 @@ fn report_zones(
fn map_queues(_tag_set: Pin<&mut TagSet<Self>>) {
build_error!(crate::error::VTABLE_DEFAULT_ERROR)
}
+
+ /// Called by the kernel when a request has been queued with the driver for too long.
+ ///
+ /// We identify the request by `queue_id` and `tag` as we cannot pass
+ /// `Owned<Request>` or `ARef<Request>`. The driver may hold either of these
+ /// already.
+ ///
+ /// A driver can use [`TagSet::tag_to_rq`] to try to obtain a request reference.
+ ///
+ /// A driver must return [`RequestTimeoutStatus::Completed`] if the request
+ /// was completed during the call. Otherwise
+ /// [`RequestTimeoutStatus::RetryLater`] must be returned, and the kernel
+ /// will retry the call later.
+ fn request_timeout(_tag_set: &TagSet<Self>, _queue_id: u32, _tag: u32) -> RequestTimeoutStatus {
+ build_error!(crate::error::VTABLE_DEFAULT_ERROR)
+ }
+}
+
+/// Return value for [`Operations::request_timeout`].
+#[repr(u32)]
+pub enum RequestTimeoutStatus {
+ /// The request was completed.
+ Completed = bindings::blk_eh_timer_return_BLK_EH_DONE,
+
+ /// The request is still processing, retry later.
+ RetryLater = bindings::blk_eh_timer_return_BLK_EH_RESET_TIMER,
+}
+
+impl RequestTimeoutStatus {
+ /// Create a [`RequestTimeoutStatus`] from an integer.
+ ///
+ /// # SAFETY
+ ///
+ /// - `value` must be one of the enum values declared for [`bindings::blk_eh_timer_return`].
+ pub unsafe fn from_raw(value: u32) -> Self {
+ // SAFETY: By function safety requirements, value is usable as `Self`.
+ unsafe { core::mem::transmute(value) }
+ }
+}
+
+impl From<RequestTimeoutStatus> for u32 {
+ fn from(value: RequestTimeoutStatus) -> Self {
+ // SAFETY: All `RequestTimeoutStatus` representations are valid as `u32`.
+ unsafe { core::mem::transmute(value) }
+ }
}
/// A vtable for blk-mq to interact with a block device driver.
@@ -496,6 +541,33 @@ impl<T: Operations> OperationsVTable<T> {
T::map_queues(tag_set);
}
+ /// This function is called by the block layer when a request has been
+ /// queued with the driver for too long.
+ ///
+ /// # Safety
+ ///
+ /// - This function may only be called by blk-mq C infrastructure.
+ /// - `rq` must point to an initialized and valid `Request`.
+ unsafe extern "C" fn request_timeout_callback(
+ rq: *mut bindings::request,
+ ) -> bindings::blk_eh_timer_return {
+ // SAFETY: `rq` is valid and initialized.
+ let hctx = unsafe { (*rq).mq_hctx };
+ // SAFETY: `rq` is valid and initialized, so `hctx` is also valid and initialized.
+ let qid = unsafe { (*hctx).queue_num };
+ // SAFETY: `rq` is valid and initialized.
+ let tag = unsafe { (*rq).tag } as u32;
+ // SAFETY: `rq` is valid and initialized, so `hctx` is also valid and initialized.
+ let queue = unsafe { (*hctx).queue };
+ // SAFETY: `rq` is valid and initialized, so is `queue`.
+ let tag_set = unsafe { (*queue).tag_set };
+ // SAFETY: As `rq` is valid, so is `tag_set`. We never create mutable referennces to a
+ // `TagSet` without proper locking.
+ let tag_set: &TagSet<T> = unsafe { TagSet::from_ptr(tag_set) };
+
+ T::request_timeout(tag_set, qid, tag).into()
+ }
+
const VTABLE: bindings::blk_mq_ops = bindings::blk_mq_ops {
queue_rq: Some(Self::queue_rq_callback),
queue_rqs: if T::HAS_QUEUE_RQS {
@@ -508,7 +580,11 @@ impl<T: Operations> OperationsVTable<T> {
put_budget: None,
set_rq_budget_token: None,
get_rq_budget_token: None,
- timeout: None,
+ timeout: if T::HAS_REQUEST_TIMEOUT {
+ Some(Self::request_timeout_callback)
+ } else {
+ None
+ },
poll: if T::HAS_POLL {
Some(Self::poll_callback)
} else {
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index e7d7217da8922..88a425a70b283 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -98,7 +98,6 @@ pub(crate) fn raw_tag_set(&self) -> *mut bindings::blk_mq_tag_set {
/// `ptr` must be a pointer to a valid and initialized `TagSet<T>`. There
/// may be no other mutable references to the tag set. The pointee must be
/// live and valid at least for the duration of the returned lifetime `'a`.
- #[expect(dead_code)]
pub(crate) unsafe fn from_ptr<'a>(ptr: *mut bindings::blk_mq_tag_set) -> &'a Self {
// SAFETY: By the safety requirements of this function, `ptr` is valid
// for use as a reference for the duration of `'a`.
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 73/79] block: rnull: add fault injection support
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (71 preceding siblings ...)
2026-02-15 23:35 ` [PATCH 72/79] block: rust: add `request_timeout` hook Andreas Hindborg
@ 2026-02-15 23:36 ` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 74/79] block: rust: add max_sectors option to `GenDiskBuilder` Andreas Hindborg
` (5 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:36 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add fault injection support to rnull using the kernel fault injection
infrastructure. When enabled via `CONFIG_FAULT_INJECTION`, users can
inject failures into I/O requests through the standard fault injection
debugfs interface.
The fault injection point is exposed as a configfs default group,
allowing per-device fault injection configuration.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/Kconfig | 11 ++++
drivers/block/rnull/configfs.rs | 57 ++++++++++++++++++-
drivers/block/rnull/rnull.rs | 120 +++++++++++++++++++++++++++++++++++++---
3 files changed, 179 insertions(+), 9 deletions(-)
diff --git a/drivers/block/rnull/Kconfig b/drivers/block/rnull/Kconfig
index 7bc5b376c128b..1ade5d8c17997 100644
--- a/drivers/block/rnull/Kconfig
+++ b/drivers/block/rnull/Kconfig
@@ -11,3 +11,14 @@ config BLK_DEV_RUST_NULL
devices that can be configured via various configuration options.
If unsure, say N.
+
+config BLK_DEV_RUST_NULL_FAULT_INJECTION
+ bool "Support fault injection for Rust Null test block driver"
+ depends on BLK_DEV_RUST_NULL && FAULT_INJECTION_CONFIGFS
+ help
+ Enable fault injection support for the Rust null block driver. This
+ allows injecting errors into block I/O operations for testing error
+ handling paths and verifying system resilience. Fault injection is
+ configured through configfs alongside the null block device settings.
+
+ If unsure, say N.
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 424722f01ab8d..b449ac882d961 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -46,6 +46,9 @@
mod macros;
+#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+use kernel::fault_injection::FaultConfig;
+
pub(crate) fn subsystem() -> impl PinInit<kernel::configfs::Subsystem<Config>, Error> {
let item_type = configfs_attrs! {
container: configfs::Subsystem<Config>,
@@ -122,10 +125,44 @@ fn make_group(
],
};
+ use kernel::configfs::CDefaultGroup;
+
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ let mut default_groups: KVec<Arc<dyn CDefaultGroup>> = KVec::new();
+
+ #[cfg(not(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION))]
+ let default_groups: KVec<Arc<dyn CDefaultGroup>> = KVec::new();
+
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ let timeout_inject = Arc::pin_init(
+ kernel::fault_injection::FaultConfig::new(c"timeout_inject"),
+ GFP_KERNEL,
+ )?;
+
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ let requeue_inject = Arc::pin_init(
+ kernel::fault_injection::FaultConfig::new(c"requeue_inject"),
+ GFP_KERNEL,
+ )?;
+
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ let init_hctx_inject = Arc::pin_init(
+ kernel::fault_injection::FaultConfig::new(c"init_hctx_fault_inject"),
+ GFP_KERNEL,
+ )?;
+
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ {
+ default_groups.push(timeout_inject.clone(), GFP_KERNEL)?;
+ default_groups.push(requeue_inject.clone(), GFP_KERNEL)?;
+ default_groups.push(init_hctx_inject.clone(), GFP_KERNEL)?;
+ }
+
let block_size = 4096;
Ok(configfs::Group::new(
name.try_into()?,
item_type,
+ // default_groups,
// TODO: cannot coerce new_mutex!() to impl PinInit<_, Error>, so put mutex inside
try_pin_init!(DeviceConfig {
data <- new_mutex!(DeviceConfigInner {
@@ -165,9 +202,15 @@ fn make_group(
zone_max_active: 0,
zone_append_max_sectors: u32::MAX,
fua: true,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject,
}),
}),
- core::iter::empty(),
+ default_groups,
))
}
}
@@ -241,6 +284,12 @@ struct DeviceConfigInner {
zone_max_active: u32,
zone_append_max_sectors: u32,
fua: bool,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject: Arc<FaultConfig>,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject: Arc<FaultConfig>,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject: Arc<FaultConfig>,
}
#[vtable]
@@ -292,6 +341,12 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
zone_max_active: guard.zone_max_active,
zone_append_max_sectors: guard.zone_append_max_sectors,
forced_unit_access: guard.fua,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject: guard.requeue_inject.clone(),
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject: guard.init_hctx_inject.clone(),
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject: guard.timeout_inject.clone(),
})?);
guard.powered = true;
} else if guard.powered && !power_op {
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index db856f03b78cb..b2b089a657f12 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -40,6 +40,7 @@
IoCompletionBatch,
Operations,
RequestList,
+ RequestTimeoutStatus,
TagSet, //
},
SECTOR_SHIFT,
@@ -90,6 +91,9 @@
use pin_init::PinInit;
use util::*;
+#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+use kernel::fault_injection::FaultConfig;
+
module! {
type: NullBlkModule,
name: "rnull_mod",
@@ -205,6 +209,8 @@
},
}
+// TODO: Fault inject via params - requires module_params string support.
+
#[pin_data]
struct NullBlkModule {
#[pin]
@@ -267,6 +273,15 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
zone_max_active: *module_parameters::zone_max_active.value(),
zone_append_max_sectors: *module_parameters::zone_append_max_sectors.value(),
forced_unit_access: *module_parameters::fua.value() != 0,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject: Arc::pin_init(FaultConfig::new(c"requeue_inject"), GFP_KERNEL)?,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject: Arc::pin_init(
+ FaultConfig::new(c"init_hctx_fault_inject"),
+ GFP_KERNEL,
+ )?,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject: Arc::pin_init(FaultConfig::new(c"timeout_inject"), GFP_KERNEL)?,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -315,6 +330,12 @@ struct NullBlkOptions<'a> {
#[cfg_attr(not(CONFIG_BLK_DEV_ZONED), expect(unused_variables))]
zone_append_max_sectors: u32,
forced_unit_access: bool,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject: Arc<FaultConfig>,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject: Arc<FaultConfig>,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject: Arc<FaultConfig>,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -339,6 +360,12 @@ struct NullBlkDevice {
#[cfg(CONFIG_BLK_DEV_ZONED)]
#[pin]
zoned: zoned::ZoneOptions,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject: Arc<FaultConfig>,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_selector: kernel::sync::atomic::Atomic<u64>,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject: Arc<FaultConfig>,
}
impl NullBlkDevice {
@@ -373,6 +400,13 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
zone_max_active,
zone_append_max_sectors,
forced_unit_access,
+
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -402,6 +436,8 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
NullBlkTagsetData {
queue_depth: hw_queue_depth,
queue_config,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject,
},
GFP_KERNEL,
)?,
@@ -450,6 +486,12 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
zone_max_active,
zone_append_max_sectors,
})?,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_inject,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ requeue_selector: Atomic::new(0),
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ timeout_inject,
}),
GFP_KERNEL,
)?;
@@ -680,7 +722,9 @@ fn handle_bad_blocks(&self, rq: &mut Owned<mq::Request<Self>>, sectors: &mut u32
badblocks::BlockStatus::None => {}
badblocks::BlockStatus::Acknowledged(mut range)
| badblocks::BlockStatus::Unacknowledged(mut range) => {
- rq.data_ref().error.store(1, ordering::Relaxed);
+ rq.data_ref()
+ .error
+ .store(block::error::code::BLK_STS_IOERR.into(), ordering::Relaxed);
if self.bad_blocks_once {
self.bad_blocks.set_good(range.clone())?;
@@ -705,6 +749,7 @@ fn end_request(rq: Owned<mq::Request<Self>>) {
let status = rq.data_ref().error.load(ordering::Relaxed);
rq.data_ref().error.store(0, ordering::Relaxed);
+ // TODO: Use correct error code
match status {
0 => rq.end_ok(),
_ => rq.end(bindings::BLK_STS_IOERR),
@@ -730,6 +775,24 @@ fn queue_rq_internal(
rq: Owned<mq::IdleRequest<Self>>,
_is_last: bool,
) -> Result<(), QueueRequestError> {
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ if rq.queue_data().requeue_inject.should_fail(1) {
+ if rq
+ .queue_data()
+ .requeue_selector
+ .fetch_add(1, ordering::Relaxed)
+ & 1
+ == 0
+ {
+ return Err(QueueRequestError {
+ request: rq,
+ });
+ } else {
+ rq.requeue(true);
+ return Ok(());
+ }
+ }
+
if this.bandwidth_limit != 0 {
if !this.bandwidth_timer.active() {
drop(this.bandwidth_timer_handle.lock().take());
@@ -755,6 +818,12 @@ fn queue_rq_internal(
let mut rq = rq.start();
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ if rq.queue_data().timeout_inject.should_fail(1) {
+ rq.data_ref().fake_timeout.store(1, ordering::Relaxed);
+ return Ok(());
+ }
+
if rq.command() == mq::Command::Flush {
if this.memory_backed {
this.storage.flush(&hw_data);
@@ -778,12 +847,13 @@ fn queue_rq_internal(
Ok(())
})();
- if let Err(e) = status {
- // Do not overwrite existing error. We do not care whether this write fails.
- let _ = rq
- .data_ref()
- .error
- .cmpxchg(0, e.to_errno(), ordering::Relaxed);
+ if status.is_err() {
+ // Do not overwrite existing error.
+ let _ = rq.data_ref().error.cmpxchg(
+ 0,
+ kernel::block::error::code::BLK_STS_IOERR.into(),
+ ordering::Relaxed,
+ );
}
if rq.is_poll() {
@@ -861,7 +931,8 @@ struct HwQueueContext {
struct Pdu {
#[pin]
timer: HrTimer<Self>,
- error: Atomic<i32>,
+ error: Atomic<u32>,
+ fake_timeout: Atomic<u32>,
}
impl HrTimerCallback for Pdu {
@@ -886,6 +957,8 @@ impl HasHrTimer<Self> for Pdu {
struct NullBlkTagsetData {
queue_depth: u32,
queue_config: Arc<Mutex<QueueConfig>>,
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ init_hctx_inject: Arc<FaultConfig>,
}
#[vtable]
@@ -899,6 +972,7 @@ fn new_request_data() -> impl PinInit<Self::RequestData> {
pin_init!(Pdu {
timer <- HrTimer::new(),
error: Atomic::new(0),
+ fake_timeout: Atomic::new(0),
})
}
@@ -953,6 +1027,11 @@ fn poll(
}
fn init_hctx(tagset_data: &NullBlkTagsetData, _hctx_idx: u32) -> Result<Self::HwData> {
+ #[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
+ if tagset_data.init_hctx_inject.should_fail(1) {
+ return Err(EFAULT);
+ }
+
KBox::pin_init(
new_spinlock!(HwQueueContext {
page: None,
@@ -1013,4 +1092,29 @@ fn map_queues(tag_set: Pin<&mut TagSet<Self>>) {
})
.unwrap()
}
+
+ fn request_timeout(tag_set: &TagSet<Self>, qid: u32, tag: u32) -> RequestTimeoutStatus {
+ if let Some(request) = tag_set.tag_to_rq(qid, tag) {
+ pr_info!("Request timed out\n");
+ // Only fail requests that are faking timeouts. Requests that time
+ // out due to memory pressure will be completed normally.
+ if request.data_ref().fake_timeout.load(ordering::Relaxed) != 0 {
+ request.data_ref().error.store(
+ block::error::code::BLK_STS_TIMEOUT.into(),
+ ordering::Relaxed,
+ );
+ request.data_ref().fake_timeout.store(0, ordering::Relaxed);
+
+ if let Ok(request) = OwnableRefCounted::try_from_shared(request) {
+ Self::end_request(request);
+ return RequestTimeoutStatus::Completed;
+ }
+ // TODO: pr_warn_once!
+ pr_warn!("Timed out request could not be completed\n");
+ }
+ } else {
+ pr_warn!("Timed out request referenced in timeout handler\n");
+ }
+ RequestTimeoutStatus::RetryLater
+ }
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 74/79] block: rust: add max_sectors option to `GenDiskBuilder`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (72 preceding siblings ...)
2026-02-15 23:36 ` [PATCH 73/79] block: rnull: add fault injection support Andreas Hindborg
@ 2026-02-15 23:36 ` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 75/79] block: rnull: allow configuration of the maximum IO size Andreas Hindborg
` (4 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:36 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Allow drivers to set the maximum I/O size when building a `GenDisk`.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/gen_disk.rs | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index b5291bc3e051d..b428e3f4207f4 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -36,6 +36,7 @@ pub struct GenDiskBuilder<T> {
zone_append_max_sectors: u32,
write_cache: bool,
forced_unit_access: bool,
+ max_sectors: u32,
_p: PhantomData<T>,
}
@@ -55,6 +56,7 @@ fn default() -> Self {
zone_append_max_sectors: 0,
write_cache: false,
forced_unit_access: false,
+ max_sectors: 0,
_p: PhantomData,
}
}
@@ -159,6 +161,12 @@ pub fn write_cache(mut self, enable: bool) -> Self {
self
}
+ /// Maximum size of a command in 512 byte sectors.
+ pub fn max_sectors(mut self, sectors: u32) -> Self {
+ self.max_sectors = sectors;
+ self
+ }
+
/// Build a new `GenDisk` and add it to the VFS.
pub fn build(
self,
@@ -178,6 +186,7 @@ pub fn build(
lim.logical_block_size = self.logical_block_size;
lim.physical_block_size = self.physical_block_size;
lim.max_hw_discard_sectors = self.max_hw_discard_sectors;
+ lim.max_sectors = self.max_sectors;
if self.rotational {
lim.features = Feature::Rotational.into();
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 75/79] block: rnull: allow configuration of the maximum IO size
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (73 preceding siblings ...)
2026-02-15 23:36 ` [PATCH 74/79] block: rust: add max_sectors option to `GenDiskBuilder` Andreas Hindborg
@ 2026-02-15 23:36 ` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 76/79] block: rust: add `virt_boundary_mask` option to `GenDiskBuilder` Andreas Hindborg
` (3 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:36 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add module parameter and configfs option for controlling the maximum size
of an IO for the emulated block device.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 5 +++++
drivers/block/rnull/rnull.rs | 10 +++++++++-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index b449ac882d961..9eaace8b4257e 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -122,6 +122,7 @@ fn make_group(
zone_append_max_sectors: 26,
poll_queues: 27,
fua: 28,
+ max_sectors: 29,
],
};
@@ -208,6 +209,7 @@ fn make_group(
requeue_inject,
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
init_hctx_inject,
+ max_sectors: 0,
}),
}),
default_groups,
@@ -290,6 +292,7 @@ struct DeviceConfigInner {
requeue_inject: Arc<FaultConfig>,
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
init_hctx_inject: Arc<FaultConfig>,
+ max_sectors: u32,
}
#[vtable]
@@ -347,6 +350,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
init_hctx_inject: guard.init_hctx_inject.clone(),
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject: guard.timeout_inject.clone(),
+ max_sectors: guard.max_sectors,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -624,3 +628,4 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
},
}
configfs_simple_bool_field!(DeviceConfig, 28, fua);
+configfs_simple_field!(DeviceConfig, 29, max_sectors, u32);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index b2b089a657f12..495a810f4f4e1 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -206,6 +206,10 @@
default: 1,
description: "Enable/disable FUA support when cache_size is used. Default: 1 (true)",
},
+ max_sectors: u32 {
+ default: 0,
+ description: "Maximum size of a command (in 512B sectors)",
+ },
},
}
@@ -282,6 +286,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
)?,
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject: Arc::pin_init(FaultConfig::new(c"timeout_inject"), GFP_KERNEL)?,
+ max_sectors: *module_parameters::max_sectors.value(),
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -336,6 +341,7 @@ struct NullBlkOptions<'a> {
init_hctx_inject: Arc<FaultConfig>,
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject: Arc<FaultConfig>,
+ max_sectors: u32,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -407,6 +413,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
init_hctx_inject,
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject,
+ max_sectors,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -502,7 +509,8 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
.physical_block_size(block_size_bytes)?
.rotational(rotational)
.write_cache(storage.cache_enabled())
- .forced_unit_access(forced_unit_access && storage.cache_enabled());
+ .forced_unit_access(forced_unit_access && storage.cache_enabled())
+ .max_sectors(max_sectors);
#[cfg(CONFIG_BLK_DEV_ZONED)]
{
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 76/79] block: rust: add `virt_boundary_mask` option to `GenDiskBuilder`
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (74 preceding siblings ...)
2026-02-15 23:36 ` [PATCH 75/79] block: rnull: allow configuration of the maximum IO size Andreas Hindborg
@ 2026-02-15 23:36 ` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 77/79] block: rnull: add `virt_boundary` option Andreas Hindborg
` (2 subsequent siblings)
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:36 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Allow Rust device drivers to set the `virt_boundary_mask` property for
block devices.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/block/mq/gen_disk.rs | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index b428e3f4207f4..bf4775dbd6d25 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -37,6 +37,7 @@ pub struct GenDiskBuilder<T> {
write_cache: bool,
forced_unit_access: bool,
max_sectors: u32,
+ virt_boundary_mask: usize,
_p: PhantomData<T>,
}
@@ -57,6 +58,7 @@ fn default() -> Self {
write_cache: false,
forced_unit_access: false,
max_sectors: 0,
+ virt_boundary_mask: 0,
_p: PhantomData,
}
}
@@ -167,6 +169,15 @@ pub fn max_sectors(mut self, sectors: u32) -> Self {
self
}
+ /// Set the I/O segment memory alignment mask for the block device. I/O requests to this device
+ /// will be split between segments wherever either the memory address of the end of the previous
+ /// segment or the memory address of the beginning of the current segment is not aligned to
+ /// virt_boundary_mask + 1 bytes.
+ pub fn virt_boundary_mask(mut self, mask: usize) -> Self {
+ self.virt_boundary_mask = mask;
+ self
+ }
+
/// Build a new `GenDisk` and add it to the VFS.
pub fn build(
self,
@@ -187,6 +198,7 @@ pub fn build(
lim.physical_block_size = self.physical_block_size;
lim.max_hw_discard_sectors = self.max_hw_discard_sectors;
lim.max_sectors = self.max_sectors;
+ lim.virt_boundary_mask = self.virt_boundary_mask;
if self.rotational {
lim.features = Feature::Rotational.into();
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 77/79] block: rnull: add `virt_boundary` option
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (75 preceding siblings ...)
2026-02-15 23:36 ` [PATCH 76/79] block: rust: add `virt_boundary_mask` option to `GenDiskBuilder` Andreas Hindborg
@ 2026-02-15 23:36 ` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 78/79] block: rnull: add `shared_tag_bitmap` config option Andreas Hindborg
2026-02-15 23:36 ` [PATCH 79/79] block: rnull: add zone offline and readonly configfs files Andreas Hindborg
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:36 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a configfs attribute to configure the virtual memory boundary mask
for the rnull block device. This allows testing how drivers and
filesystems handle devices with specific alignment requirements.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 5 +++++
drivers/block/rnull/rnull.rs | 17 ++++++++++++++++-
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 9eaace8b4257e..8b9ad8a1a243b 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -123,6 +123,7 @@ fn make_group(
poll_queues: 27,
fua: 28,
max_sectors: 29,
+ virt_boundary: 30,
],
};
@@ -210,6 +211,7 @@ fn make_group(
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
init_hctx_inject,
max_sectors: 0,
+ virt_boundary: false,
}),
}),
default_groups,
@@ -293,6 +295,7 @@ struct DeviceConfigInner {
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
init_hctx_inject: Arc<FaultConfig>,
max_sectors: u32,
+ virt_boundary: bool,
}
#[vtable]
@@ -351,6 +354,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject: guard.timeout_inject.clone(),
max_sectors: guard.max_sectors,
+ virt_boundary: guard.virt_boundary,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -629,3 +633,4 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
}
configfs_simple_bool_field!(DeviceConfig, 28, fua);
configfs_simple_field!(DeviceConfig, 29, max_sectors, u32);
+configfs_simple_bool_field!(DeviceConfig, 30, virt_boundary);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 495a810f4f4e1..dfdb56bd76f52 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -28,7 +28,10 @@
BadBlocks, //
},
bio::Segment,
- error::{BlkError, BlkResult},
+ error::{
+ BlkError,
+ BlkResult, //
+ },
mq::{
self,
gen_disk::{
@@ -53,6 +56,7 @@
impl_has_hr_timer,
new_mutex,
new_spinlock,
+ page::PAGE_SIZE,
pr_info,
prelude::*,
revocable::Revocable,
@@ -210,6 +214,10 @@
default: 0,
description: "Maximum size of a command (in 512B sectors)",
},
+ virt_boundary: u8 {
+ default: 0,
+ description: "Set alignment requirement for IO buffers to be page size.",
+ },
},
}
@@ -287,6 +295,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject: Arc::pin_init(FaultConfig::new(c"timeout_inject"), GFP_KERNEL)?,
max_sectors: *module_parameters::max_sectors.value(),
+ virt_boundary: *module_parameters::virt_boundary.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -342,6 +351,7 @@ struct NullBlkOptions<'a> {
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject: Arc<FaultConfig>,
max_sectors: u32,
+ virt_boundary: bool,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -414,6 +424,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
#[cfg(CONFIG_BLK_DEV_RUST_NULL_FAULT_INJECTION)]
timeout_inject,
max_sectors,
+ virt_boundary,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -512,6 +523,10 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
.forced_unit_access(forced_unit_access && storage.cache_enabled())
.max_sectors(max_sectors);
+ if virt_boundary {
+ builder = builder.virt_boundary_mask(PAGE_SIZE - 1);
+ }
+
#[cfg(CONFIG_BLK_DEV_ZONED)]
{
builder = builder
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 78/79] block: rnull: add `shared_tag_bitmap` config option
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (76 preceding siblings ...)
2026-02-15 23:36 ` [PATCH 77/79] block: rnull: add `virt_boundary` option Andreas Hindborg
@ 2026-02-15 23:36 ` Andreas Hindborg
2026-02-15 23:36 ` [PATCH 79/79] block: rnull: add zone offline and readonly configfs files Andreas Hindborg
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:36 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add a configfs attribute and module parameter to enable the
`BLK_MQ_F_TAG_HCTX_SHARED` flag for the rnull tag set. When enabled,
a tag bitmap is shared across all hardware queues.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 5 +++++
drivers/block/rnull/rnull.rs | 11 +++++++++++
rust/kernel/block/mq/tag_set/flags.rs | 4 ++++
3 files changed, 20 insertions(+)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 8b9ad8a1a243b..395da68d96dc6 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -124,6 +124,7 @@ fn make_group(
fua: 28,
max_sectors: 29,
virt_boundary: 30,
+ shared_tag_bitmap: 31,
],
};
@@ -212,6 +213,7 @@ fn make_group(
init_hctx_inject,
max_sectors: 0,
virt_boundary: false,
+ shared_tag_bitmap: false,
}),
}),
default_groups,
@@ -296,6 +298,7 @@ struct DeviceConfigInner {
init_hctx_inject: Arc<FaultConfig>,
max_sectors: u32,
virt_boundary: bool,
+ shared_tag_bitmap: bool,
}
#[vtable]
@@ -355,6 +358,7 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
timeout_inject: guard.timeout_inject.clone(),
max_sectors: guard.max_sectors,
virt_boundary: guard.virt_boundary,
+ shared_tag_bitmap: guard.shared_tag_bitmap,
})?);
guard.powered = true;
} else if guard.powered && !power_op {
@@ -634,3 +638,4 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_bool_field!(DeviceConfig, 28, fua);
configfs_simple_field!(DeviceConfig, 29, max_sectors, u32);
configfs_simple_bool_field!(DeviceConfig, 30, virt_boundary);
+configfs_simple_bool_field!(DeviceConfig, 31, shared_tag_bitmap);
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index dfdb56bd76f52..5bf965908ef63 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -218,6 +218,10 @@
default: 0,
description: "Set alignment requirement for IO buffers to be page size.",
},
+ shared_tag_bitmap: u8 {
+ default: 0,
+ description: "Use shared tag bitmap for all submission queues for blk-mq.",
+ },
},
}
@@ -296,6 +300,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
timeout_inject: Arc::pin_init(FaultConfig::new(c"timeout_inject"), GFP_KERNEL)?,
max_sectors: *module_parameters::max_sectors.value(),
virt_boundary: *module_parameters::virt_boundary.value() != 0,
+ shared_tag_bitmap: *module_parameters::shared_tag_bitmap.value() != 0,
})?;
disks.push(disk, GFP_KERNEL)?;
}
@@ -352,6 +357,7 @@ struct NullBlkOptions<'a> {
timeout_inject: Arc<FaultConfig>,
max_sectors: u32,
virt_boundary: bool,
+ shared_tag_bitmap: bool,
}
static SHARED_TAG_SET: SetOnce<Arc<TagSet<NullBlkDevice>>> = SetOnce::new();
@@ -425,6 +431,7 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
timeout_inject,
max_sectors,
virt_boundary,
+ shared_tag_bitmap,
} = options;
let mut flags = mq::tag_set::Flags::default();
@@ -437,6 +444,10 @@ fn new(options: NullBlkOptions<'_>) -> Result<Arc<GenDisk<Self>>> {
flags |= mq::tag_set::Flag::NoDefaultScheduler;
}
+ if shared_tag_bitmap {
+ flags |= mq::tag_set::Flag::TagHctxShared;
+ }
+
if home_node > kernel::num_online_nodes().try_into()? {
return Err(code::EINVAL);
}
diff --git a/rust/kernel/block/mq/tag_set/flags.rs b/rust/kernel/block/mq/tag_set/flags.rs
index 1fca4fcb4dd20..cc5f54781cfd8 100644
--- a/rust/kernel/block/mq/tag_set/flags.rs
+++ b/rust/kernel/block/mq/tag_set/flags.rs
@@ -19,5 +19,9 @@ pub enum Flag {
/// Select 'none' during queue registration in case of a single hwq or shared
/// hwqs instead of 'mq-deadline'.
NoDefaultScheduler = bindings::BLK_MQ_F_NO_SCHED_BY_DEFAULT,
+
+ /// Use shared tag bitmap for all submission queues.
+ TagHctxShared = bindings::BLK_MQ_F_TAG_HCTX_SHARED,
+
}
}
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread* [PATCH 79/79] block: rnull: add zone offline and readonly configfs files
2026-02-15 23:34 [PATCH 00/79] block: rnull: complete the rust null block driver Andreas Hindborg
` (77 preceding siblings ...)
2026-02-15 23:36 ` [PATCH 78/79] block: rnull: add `shared_tag_bitmap` config option Andreas Hindborg
@ 2026-02-15 23:36 ` Andreas Hindborg
78 siblings, 0 replies; 114+ messages in thread
From: Andreas Hindborg @ 2026-02-15 23:36 UTC (permalink / raw)
To: Boqun Feng, Jens Axboe, Miguel Ojeda, Gary Guo,
Björn Roy Baron, Benno Lossin, Alice Ryhl, Trevor Gross,
Danilo Krummrich, FUJITA Tomonori, Frederic Weisbecker,
Lyude Paul, Thomas Gleixner, Anna-Maria Behnsen, John Stultz,
Stephen Boyd, Lorenzo Stoakes, Liam R. Howlett
Cc: linux-block, rust-for-linux, linux-kernel, linux-mm,
Andreas Hindborg
Add configfs attributes for managing zone states in the rnull zoned
block device emulation. The `zone_offline` and `zone_readonly`
attributes allow setting specific zones to offline or read-only states,
which is useful for testing how applications handle degraded zones.
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
drivers/block/rnull/configfs.rs | 80 +++++++++++++++++++++++++++++++++++
drivers/block/rnull/disk_storage.rs | 59 +++++++++++++-------------
drivers/block/rnull/rnull.rs | 2 +-
drivers/block/rnull/zoned.rs | 83 ++++++++++++++++++++++++++-----------
4 files changed, 168 insertions(+), 56 deletions(-)
diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 395da68d96dc6..1c0d95ded7e9f 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -125,6 +125,8 @@ fn make_group(
max_sectors: 29,
virt_boundary: 30,
shared_tag_bitmap: 31,
+ zone_offline: 32,
+ zone_readonly: 33,
],
};
@@ -639,3 +641,81 @@ fn store(this: &DeviceConfig, page: &[u8]) -> Result {
configfs_simple_field!(DeviceConfig, 29, max_sectors, u32);
configfs_simple_bool_field!(DeviceConfig, 30, virt_boundary);
configfs_simple_bool_field!(DeviceConfig, 31, shared_tag_bitmap);
+
+#[cfg(CONFIG_BLK_DEV_ZONED)]
+fn set_zone_condition(
+ this: &DeviceConfig,
+ sector: u64,
+ cb: impl FnOnce(
+ &crate::zoned::ZoneOptions,
+ &DiskStorage,
+ &mut crate::zoned::ZoneDescriptor,
+ ) -> Result,
+) -> Result {
+ use crate::zoned::ZoneType;
+ let data_guard = this.data.lock();
+ let null_disk = data_guard.disk.as_ref().ok_or(EBUSY)?.queue_data();
+ let storage = &null_disk.storage;
+ let zone_options = &null_disk.zoned;
+ zone_options.enabled.then_some(()).ok_or(EINVAL)?;
+ let mut zone = zone_options.zone(sector)?.lock();
+
+ if zone.kind == ZoneType::Conventional {
+ return Err(EINVAL);
+ }
+
+ cb(zone_options, storage, &mut zone)
+}
+
+#[cfg(CONFIG_BLK_DEV_ZONED)]
+configfs_attribute!(
+ DeviceConfig,
+ 32,
+ show: |_this, _page| Ok(0),
+ store: |this,page| {
+ let text = core::str::from_utf8(page)?.trim();
+ let sector = text.parse().map_err(|_| EINVAL)?;
+
+ set_zone_condition(this, sector, |zone_options, storage, zone| {
+ zone_options.offline_zone(storage, zone)
+ })?;
+ Ok(())
+ },
+);
+
+#[cfg(CONFIG_BLK_DEV_ZONED)]
+configfs_attribute!(
+ DeviceConfig,
+ 33,
+ show: |_this, _page| Ok(0),
+ store: |this,page| {
+ let text = core::str::from_utf8(page)?.trim();
+ let sector = text.parse().map_err(|_| EINVAL)?;
+
+ set_zone_condition(this, sector, |zone_options, storage, zone| {
+ zone_options.read_only_zone(storage, zone)
+ })?;
+
+ Ok(())
+ },
+);
+
+#[cfg(not(CONFIG_BLK_DEV_ZONED))]
+configfs_attribute!(
+ DeviceConfig,
+ 32,
+ show: |this, page| {Ok(0)},
+ store: |this,page| {
+ Err(ENOTSUPP)
+ },
+);
+
+#[cfg(not(CONFIG_BLK_DEV_ZONED))]
+configfs_attribute!(
+ DeviceConfig,
+ 33,
+ show: |this, page| {Ok(0)},
+ store: |this,page| {
+ Err(ENOTSUPP)
+ },
+);
diff --git a/drivers/block/rnull/disk_storage.rs b/drivers/block/rnull/disk_storage.rs
index d9f2703957fc0..802e9534ca2a5 100644
--- a/drivers/block/rnull/disk_storage.rs
+++ b/drivers/block/rnull/disk_storage.rs
@@ -65,27 +65,45 @@ pub(crate) fn lock(&self) -> SpinLockGuard<'_, Pin<KBox<TreeContainer>>> {
self.trees.lock()
}
- pub(crate) fn discard(
- &self,
- hw_data: &Pin<&SpinLock<HwQueueContext>>,
- mut sector: u64,
- sectors: u32,
- ) {
- let mut tree_guard = self.lock();
- let mut hw_data_guard = hw_data.lock();
-
- let mut access = self.access(&mut tree_guard, &mut hw_data_guard, None);
+ pub(crate) fn discard(&self, mut sector: u64, sectors: u32) {
+ let tree_guard = self.lock();
+ let mut cache_guard = tree_guard.cache_tree.lock();
+ let mut disk_guard = tree_guard.cache_tree.lock();
let mut remaining_bytes = sectors_to_bytes(sectors);
while remaining_bytes > 0 {
- access.free_sector(sector);
+ self.free_sector(&mut cache_guard, &mut disk_guard, sector);
let processed = remaining_bytes.min(self.block_size);
sector += Into::<u64>::into(bytes_to_sectors(processed));
remaining_bytes -= processed;
}
}
+ fn free_sector_tree(tree_access: &mut xarray::Guard<'_, TreeNode>, sector: u64) {
+ let index = DiskStorageAccess::to_index(sector);
+ if let Some(page) = tree_access.get_mut(index) {
+ page.set_free(sector);
+
+ if page.is_empty() {
+ tree_access.remove(index);
+ }
+ }
+ }
+
+ pub(crate) fn free_sector<'a>(
+ &self,
+ cache_guard: &mut xarray::Guard<'a, TreeNode>,
+ disk_guard: &mut xarray::Guard<'a, TreeNode>,
+ sector: u64,
+ ) {
+ if self.cache_size > 0 {
+ Self::free_sector_tree(cache_guard, sector);
+ }
+
+ Self::free_sector_tree(disk_guard, sector);
+ }
+
pub(crate) fn flush(&self, hw_data: &Pin<&SpinLock<HwQueueContext>>) {
let mut tree_guard = self.lock();
let mut hw_data_guard = hw_data.lock();
@@ -262,25 +280,6 @@ pub(crate) fn get_read_page(&self, sector: u64) -> Option<&NullBlockPage> {
self.disk_guard.get(index)
}
}
-
- fn free_sector_tree(tree_access: &mut xarray::Guard<'_, TreeNode>, sector: u64) {
- let index = Self::to_index(sector);
- if let Some(page) = tree_access.get_mut(index) {
- page.set_free(sector);
-
- if page.is_empty() {
- tree_access.remove(index);
- }
- }
- }
-
- pub(crate) fn free_sector(&mut self, sector: u64) {
- if self.disk_storage.cache_size > 0 {
- Self::free_sector_tree(&mut self.cache_guard, sector);
- }
-
- Self::free_sector_tree(&mut self.disk_guard, sector);
- }
}
type Tree = XArray<TreeNode>;
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 5bf965908ef63..91f8636d74cca 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -739,7 +739,7 @@ fn handle_regular_command(
if self.memory_backed {
if rq.command() == mq::Command::Discard {
- self.storage.discard(hw_data, rq.sector(), sectors);
+ self.storage.discard(rq.sector(), sectors);
} else {
self.transfer(hw_data, rq, rq.command(), sectors)?;
}
diff --git a/drivers/block/rnull/zoned.rs b/drivers/block/rnull/zoned.rs
index 0f15f4cc4e5c3..3b8ebf5449a8d 100644
--- a/drivers/block/rnull/zoned.rs
+++ b/drivers/block/rnull/zoned.rs
@@ -178,7 +178,7 @@ pub(crate) fn handle_zoned_command(
match rq.command() {
ZoneAppend | Write => self.zoned_write(hw_data, rq)?,
ZoneReset | ZoneResetAll | ZoneOpen | ZoneClose | ZoneFinish => {
- self.zone_management(hw_data, rq)?
+ self.zone_management(rq)?
}
_ => self.zoned_read(hw_data, rq)?,
}
@@ -186,18 +186,14 @@ pub(crate) fn handle_zoned_command(
Ok(())
}
- fn zone_management(
- &self,
- hw_data: &Pin<&SpinLock<HwQueueContext>>,
- rq: &mut Owned<mq::Request<Self>>,
- ) -> Result {
+ fn zone_management(&self, rq: &mut Owned<mq::Request<Self>>) -> Result {
if rq.command() == mq::Command::ZoneResetAll {
for zone in self.zoned.zones_iter() {
let mut zone = zone.lock();
use ZoneCondition::*;
match zone.condition {
Empty | ReadOnly | Offline => continue,
- _ => self.zoned.reset_zone(&self.storage, hw_data, &mut zone)?,
+ _ => self.zoned.reset_zone(&self.storage, &mut zone)?,
}
}
@@ -213,10 +209,10 @@ fn zone_management(
use mq::Command::*;
match rq.command() {
- ZoneOpen => self.zoned.open_zone(&mut zone, rq.sector()),
+ ZoneOpen => self.zoned.open_zone(&mut zone),
ZoneClose => self.zoned.close_zone(&mut zone),
- ZoneReset => self.zoned.reset_zone(&self.storage, hw_data, &mut zone),
- ZoneFinish => self.zoned.finish_zone(&mut zone, rq.sector()),
+ ZoneReset => self.zoned.reset_zone(&self.storage, &mut zone),
+ ZoneFinish => self.zoned.finish_zone(&mut zone),
_ => Err(EIO),
}
}
@@ -282,7 +278,7 @@ fn zoned_write(
if self.zoned.use_accounting() {
let mut accounting = self.zoned.accounting.lock();
self.zoned
- .check_zone_resources(&mut accounting, &mut zone, rq.sector())?;
+ .check_zone_resources(&mut accounting, &mut zone)?;
if zone.condition == ZoneCondition::Closed {
accounting.closed -= 1;
@@ -365,7 +361,7 @@ fn zone_no(&self, sector: u64) -> usize {
(sector >> self.size_sectors.ilog2()) as usize
}
- fn zone(&self, sector: u64) -> Result<&Mutex<ZoneDescriptor>> {
+ pub(crate) fn zone(&self, sector: u64) -> Result<&Mutex<ZoneDescriptor>> {
self.zones.get(self.zone_no(sector)).ok_or(EINVAL)
}
@@ -418,7 +414,7 @@ fn try_close_implicit_open_zone(&self, accounting: &mut ZoneAccounting, sector:
Err(EINVAL)
}
- fn open_zone(&self, zone: &mut ZoneDescriptor, sector: u64) -> Result {
+ fn open_zone(&self, zone: &mut ZoneDescriptor) -> Result {
if zone.kind == ZoneType::Conventional {
return Err(EINVAL);
}
@@ -434,13 +430,13 @@ fn open_zone(&self, zone: &mut ZoneDescriptor, sector: u64) -> Result {
let mut accounting = self.accounting.lock();
match zone.condition {
Empty => {
- self.check_zone_resources(&mut accounting, zone, sector)?;
+ self.check_zone_resources(&mut accounting, zone)?;
}
ImplicitOpen => {
accounting.implicit_open -= 1;
}
Closed => {
- self.check_zone_resources(&mut accounting, zone, sector)?;
+ self.check_zone_resources(&mut accounting, zone)?;
accounting.closed -= 1;
}
_ => (),
@@ -457,14 +453,13 @@ fn check_zone_resources(
&self,
accounting: &mut ZoneAccounting,
zone: &mut ZoneDescriptor,
- sector: u64,
) -> Result {
match zone.condition {
ZoneCondition::Empty => {
self.check_active_zones(accounting)?;
- self.check_open_zones(accounting, sector)
+ self.check_open_zones(accounting, zone.start_sector)
}
- ZoneCondition::Closed => self.check_open_zones(accounting, sector),
+ ZoneCondition::Closed => self.check_open_zones(accounting, zone.start_sector),
_ => Err(EIO),
}
}
@@ -533,7 +528,7 @@ fn close_zone(&self, zone: &mut ZoneDescriptor) -> Result {
Ok(())
}
- fn finish_zone(&self, zone: &mut ZoneDescriptor, sector: u64) -> Result {
+ fn finish_zone(&self, zone: &mut ZoneDescriptor) -> Result {
if zone.kind == ZoneType::Conventional {
return Err(EINVAL);
}
@@ -545,12 +540,12 @@ fn finish_zone(&self, zone: &mut ZoneDescriptor, sector: u64) -> Result {
match zone.condition {
Full => return Ok(()),
Empty => {
- self.check_zone_resources(&mut accounting, zone, sector)?;
+ self.check_zone_resources(&mut accounting, zone)?;
}
ImplicitOpen => accounting.implicit_open -= 1,
ExplicitOpen => accounting.explicit_open -= 1,
Closed => {
- self.check_zone_resources(&mut accounting, zone, sector)?;
+ self.check_zone_resources(&mut accounting, zone)?;
accounting.closed -= 1;
}
_ => return Err(EIO),
@@ -566,7 +561,6 @@ fn finish_zone(&self, zone: &mut ZoneDescriptor, sector: u64) -> Result {
fn reset_zone(
&self,
storage: &crate::disk_storage::DiskStorage,
- hw_data: &Pin<&SpinLock<HwQueueContext>>,
zone: &mut ZoneDescriptor,
) -> Result {
if zone.kind == ZoneType::Conventional {
@@ -589,16 +583,55 @@ fn reset_zone(
zone.condition = ZoneCondition::Empty;
zone.write_pointer = zone.start_sector;
- storage.discard(hw_data, zone.start_sector, zone.size_sectors);
+ storage.discard(zone.start_sector, zone.size_sectors);
+
+ Ok(())
+ }
+
+ fn set_zone_condition(
+ &self,
+ storage: &crate::disk_storage::DiskStorage,
+ zone: &mut ZoneDescriptor,
+ condition: ZoneCondition,
+ ) -> Result {
+ if zone.condition == condition {
+ zone.condition = ZoneCondition::Empty;
+ zone.write_pointer = zone.start_sector;
+ storage.discard(zone.start_sector, zone.size_sectors);
+ } else {
+ if matches!(
+ zone.condition,
+ ZoneCondition::ReadOnly | ZoneCondition::Offline
+ ) {
+ self.finish_zone(zone)?;
+ }
+ zone.condition = ZoneCondition::Offline;
+ zone.write_pointer = u64::MAX;
+ }
Ok(())
}
+ pub(crate) fn offline_zone(
+ &self,
+ storage: &crate::disk_storage::DiskStorage,
+ zone: &mut ZoneDescriptor,
+ ) -> Result {
+ self.set_zone_condition(storage, zone, ZoneCondition::Offline)
+ }
+
+ pub(crate) fn read_only_zone(
+ &self,
+ storage: &crate::disk_storage::DiskStorage,
+ zone: &mut ZoneDescriptor,
+ ) -> Result {
+ self.set_zone_condition(storage, zone, ZoneCondition::ReadOnly)
+ }
}
pub(crate) struct ZoneDescriptor {
start_sector: u64,
size_sectors: u32,
- kind: ZoneType,
+ pub(crate) kind: ZoneType,
capacity_sectors: u32,
write_pointer: u64,
condition: ZoneCondition,
@@ -626,7 +659,7 @@ fn check_bounds_read(&self, sector: u64, sectors: u32) -> Result {
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[repr(u32)]
-enum ZoneType {
+pub(crate) enum ZoneType {
Conventional = bindings::blk_zone_type_BLK_ZONE_TYPE_CONVENTIONAL,
SequentialWriteRequired = bindings::blk_zone_type_BLK_ZONE_TYPE_SEQWRITE_REQ,
#[expect(dead_code)]
--
2.51.2
^ permalink raw reply related [flat|nested] 114+ messages in thread