[PATCH 0/9] rust: use `kernel::{fmt,prelude::fmt!}`

[PATCH 0/9] rust: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

This is series 2a/5 of the migration to `core::ffi::CStr`[0].
20250704-core-cstr-prepare-v1-0-a91524037783@gmail.com.

This series depends on the prior series[0] and is intended to go through
the rust tree to reduce the number of release cycles required to
complete the work.

Subsystem maintainers: I would appreciate your `Acked-by`s so that this
can be taken through Miguel's tree (where the other series must go).

[0] https://lore.kernel.org/all/20250704-core-cstr-prepare-v1-0-a91524037783@gmail.com/

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
Tamir Duberstein (9):
      gpu: nova-core: use `kernel::{fmt,prelude::fmt!}`
      rust: alloc: use `kernel::{fmt,prelude::fmt!}`
      rust: block: use `kernel::{fmt,prelude::fmt!}`
      rust: device: use `kernel::{fmt,prelude::fmt!}`
      rust: file: use `kernel::{fmt,prelude::fmt!}`
      rust: kunit: use `kernel::{fmt,prelude::fmt!}`
      rust: pin-init: use `kernel::{fmt,prelude::fmt!}`
      rust: seq_file: use `kernel::{fmt,prelude::fmt!}`
      rust: sync: use `kernel::{fmt,prelude::fmt!}`

 drivers/block/rnull.rs               | 2 +-
 drivers/gpu/nova-core/gpu.rs         | 3 +--
 drivers/gpu/nova-core/regs/macros.rs | 6 +++---
 rust/kernel/alloc/kbox.rs            | 2 +-
 rust/kernel/alloc/kvec.rs            | 2 +-
 rust/kernel/alloc/kvec/errors.rs     | 2 +-
 rust/kernel/block/mq.rs              | 2 +-
 rust/kernel/block/mq/gen_disk.rs     | 2 +-
 rust/kernel/block/mq/raw_writer.rs   | 3 +--
 rust/kernel/device.rs                | 6 +++---
 rust/kernel/fs/file.rs               | 5 +++--
 rust/kernel/init.rs                  | 4 ++--
 rust/kernel/kunit.rs                 | 8 ++++----
 rust/kernel/seq_file.rs              | 6 +++---
 rust/kernel/sync/arc.rs              | 3 +--
 scripts/rustdoc_test_gen.rs          | 2 +-
 16 files changed, 28 insertions(+), 30 deletions(-)
---
base-commit: 769e324b66b0d92d04f315d0c45a0f72737c7494
change-id: 20250709-core-cstr-fanout-1-f20611832272
prerequisite-change-id: 20250704-core-cstr-prepare-9b9e6a7bd57e:v1
prerequisite-patch-id: 83b1239d1805f206711a5a936bbb61c83227d573
prerequisite-patch-id: a0355dd0efcc945b0565dc4e5a0f42b5a3d29c7e
prerequisite-patch-id: 8585bf441cfab705181f5606c63483c2e88d25aa
prerequisite-patch-id: 04ec344c0bc23f90dbeac10afe26df1a86ce53ec
prerequisite-patch-id: a2fc6cd05fce6d6da8d401e9f8a905bb5c0b2f27
prerequisite-patch-id: f14c099c87562069f25fb7aea6d9aae4086c49a8

Best regards,
--  
Tamir Duberstein <tamird@gmail.com>

[PATCH 1/9] gpu: nova-core: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 drivers/gpu/nova-core/gpu.rs         | 3 +--
 drivers/gpu/nova-core/regs/macros.rs | 6 +++---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 60b86f370284..f1d72da7fddd 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -1,12 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use kernel::{device, devres::Devres, error::code::*, pci, prelude::*};
+use kernel::{device, devres::Devres, error::code::*, fmt, pci, prelude::*};
 
 use crate::driver::Bar0;
 use crate::firmware::{Firmware, FIRMWARE_VERSION};
 use crate::regs;
 use crate::util;
-use core::fmt;
 
 macro_rules! define_chipset {
     ({ $($variant:ident = $value:expr),* $(,)* }) =>
diff --git a/drivers/gpu/nova-core/regs/macros.rs b/drivers/gpu/nova-core/regs/macros.rs
index 6851af8b5885..759773a19480 100644
--- a/drivers/gpu/nova-core/regs/macros.rs
+++ b/drivers/gpu/nova-core/regs/macros.rs
@@ -106,10 +106,10 @@ macro_rules! register {
 
         // TODO: display the raw hex value, then the value of all the fields. This requires
         // matching the fields, which will complexify the syntax considerably...
-        impl ::core::fmt::Debug for $name {
-            fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
+        impl ::kernel::fmt::Debug for $name {
+            fn fmt(&self, f: &mut ::kernel::fmt::Formatter<'_>) -> ::kernel::fmt::Result {
                 f.debug_tuple(stringify!($name))
-                    .field(&format_args!("0x{0:x}", &self.0))
+                    .field(&::kernel::prelude::fmt!("0x{0:x}", &self.0))
                     .finish()
             }
         }

-- 
2.50.0

[PATCH 2/9] rust: alloc: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/kernel/alloc/kbox.rs        | 2 +-
 rust/kernel/alloc/kvec.rs        | 2 +-
 rust/kernel/alloc/kvec/errors.rs | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs
index ccf1df7da96c..96db3cf8d782 100644
--- a/rust/kernel/alloc/kbox.rs
+++ b/rust/kernel/alloc/kbox.rs
@@ -7,7 +7,6 @@
 use super::{AllocError, Allocator, Flags};
 use core::alloc::Layout;
 use core::borrow::{Borrow, BorrowMut};
-use core::fmt;
 use core::marker::PhantomData;
 use core::mem::ManuallyDrop;
 use core::mem::MaybeUninit;
@@ -16,6 +15,7 @@
 use core::ptr::NonNull;
 use core::result::Result;
 
+use crate::fmt;
 use crate::init::InPlaceInit;
 use crate::types::ForeignOwnable;
 use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption};
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs
index 0477041cbc03..a642bdc9cea2 100644
--- a/rust/kernel/alloc/kvec.rs
+++ b/rust/kernel/alloc/kvec.rs
@@ -7,8 +7,8 @@
     layout::ArrayLayout,
     AllocError, Allocator, Box, Flags,
 };
+use crate::fmt;
 use core::{
-    fmt,
     marker::PhantomData,
     mem::{ManuallyDrop, MaybeUninit},
     ops::Deref,
diff --git a/rust/kernel/alloc/kvec/errors.rs b/rust/kernel/alloc/kvec/errors.rs
index 348b8d27e102..21a920a4b09b 100644
--- a/rust/kernel/alloc/kvec/errors.rs
+++ b/rust/kernel/alloc/kvec/errors.rs
@@ -2,7 +2,7 @@
 
 //! Errors for the [`Vec`] type.
 
-use core::fmt::{self, Debug, Formatter};
+use kernel::fmt::{self, Debug, Formatter};
 use kernel::prelude::*;
 
 /// Error type for [`Vec::push_within_capacity`].

-- 
2.50.0

[PATCH 3/9] rust: block: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/288089-General/topic/Custom.20formatting/with/516476467
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 drivers/block/rnull.rs             | 2 +-
 rust/kernel/block/mq.rs            | 2 +-
 rust/kernel/block/mq/gen_disk.rs   | 2 +-
 rust/kernel/block/mq/raw_writer.rs | 3 +--
 4 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/block/rnull.rs b/drivers/block/rnull.rs
index d07e76ae2c13..6366da12c5a5 100644
--- a/drivers/block/rnull.rs
+++ b/drivers/block/rnull.rs
@@ -51,7 +51,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
                 .logical_block_size(4096)?
                 .physical_block_size(4096)?
                 .rotational(false)
-                .build(format_args!("rnullb{}", 0), tagset)
+                .build(fmt!("rnullb{}", 0), tagset)
         })();
 
         try_pin_init!(Self {
diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs
index 831445d37181..61ea35bba7d5 100644
--- a/rust/kernel/block/mq.rs
+++ b/rust/kernel/block/mq.rs
@@ -82,7 +82,7 @@
 //!     Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?;
 //! let mut disk = gen_disk::GenDiskBuilder::new()
 //!     .capacity_sectors(4096)
-//!     .build(format_args!("myblk"), tagset)?;
+//!     .build(fmt!("myblk"), tagset)?;
 //!
 //! # Ok::<(), kernel::error::Error>(())
 //! ```
diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index cd54cd64ea88..494c95623b97 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -6,9 +6,9 @@
 //! C header: [`include/linux/blk_mq.h`](srctree/include/linux/blk_mq.h)
 
 use crate::block::mq::{raw_writer::RawWriter, Operations, TagSet};
+use crate::fmt::{self, Write};
 use crate::{bindings, error::from_err_ptr, error::Result, sync::Arc};
 use crate::{error, static_lock_class};
-use core::fmt::{self, Write};
 
 /// A builder for [`GenDisk`].
 ///
diff --git a/rust/kernel/block/mq/raw_writer.rs b/rust/kernel/block/mq/raw_writer.rs
index 7e2159e4f6a6..d311e24e2595 100644
--- a/rust/kernel/block/mq/raw_writer.rs
+++ b/rust/kernel/block/mq/raw_writer.rs
@@ -1,8 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use core::fmt::{self, Write};
-
 use crate::error::Result;
+use crate::fmt::{self, Write};
 use crate::prelude::EINVAL;
 
 /// A mutable reference to a byte buffer where a string can be written into.

-- 
2.50.0

[PATCH 4/9] rust: device: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/kernel/device.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 5c946af3a4d5..9e9ecdb1beec 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -5,11 +5,11 @@
 //! C header: [`include/linux/device.h`](srctree/include/linux/device.h)
 
 use crate::{
-    bindings,
+    bindings, fmt,
     str::CStr,
     types::{ARef, Opaque},
 };
-use core::{fmt, marker::PhantomData, ptr};
+use core::{marker::PhantomData, ptr};
 
 #[cfg(CONFIG_PRINTK)]
 use crate::c_str;
@@ -345,7 +345,7 @@ macro_rules! impl_device_context_into_aref {
 macro_rules! dev_printk {
     ($method:ident, $dev:expr, $($f:tt)*) => {
         {
-            ($dev).$method(::core::format_args!($($f)*));
+            ($dev).$method($crate::prelude::fmt!($($f)*));
         }
     }
 }

-- 
2.50.0

[PATCH 5/9] rust: file: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/kernel/fs/file.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/rust/kernel/fs/file.rs b/rust/kernel/fs/file.rs
index 35fd5db35c46..67a3654f0fd3 100644
--- a/rust/kernel/fs/file.rs
+++ b/rust/kernel/fs/file.rs
@@ -11,6 +11,7 @@
     bindings,
     cred::Credential,
     error::{code::*, Error, Result},
+    fmt,
     types::{ARef, AlwaysRefCounted, NotThreadSafe, Opaque},
 };
 use core::ptr;
@@ -460,8 +461,8 @@ fn from(_: BadFdError) -> Error {
     }
 }
 
-impl core::fmt::Debug for BadFdError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+impl fmt::Debug for BadFdError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.pad("EBADF")
     }
 }

-- 
2.50.0

[PATCH 6/9] rust: kunit: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/kernel/kunit.rs        | 8 ++++----
 scripts/rustdoc_test_gen.rs | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 099a61bbb8f4..42498cb93f33 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -6,8 +6,8 @@
 //!
 //! Reference: <https://docs.kernel.org/dev-tools/kunit/index.html>
 
+use crate::fmt;
 use crate::prelude::*;
-use core::fmt;
 
 #[cfg(CONFIG_PRINTK)]
 use crate::c_str;
@@ -74,14 +74,14 @@ macro_rules! kunit_assert {
                 // mistake (it is hidden to prevent that).
                 //
                 // This mimics KUnit's failed assertion format.
-                $crate::kunit::err(format_args!(
+                $crate::kunit::err($crate::prelude::fmt!(
                     "    # {}: ASSERTION FAILED at {FILE}:{LINE}\n",
                     $name
                 ));
-                $crate::kunit::err(format_args!(
+                $crate::kunit::err($crate::prelude::fmt!(
                     "    Expected {CONDITION} to be true, but is false\n"
                 ));
-                $crate::kunit::err(format_args!(
+                $crate::kunit::err($crate::prelude::fmt!(
                     "    Failure not reported to KUnit since this is a non-KUnit task\n"
                 ));
                 break 'out;
diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs
index 1ca253594d38..507d36875196 100644
--- a/scripts/rustdoc_test_gen.rs
+++ b/scripts/rustdoc_test_gen.rs
@@ -201,7 +201,7 @@ macro_rules! assert_eq {{
     // This follows the syntax for declaring test metadata in the proposed KTAP v2 spec, which may
     // be used for the proposed KUnit test attributes API. Thus hopefully this will make migration
     // easier later on.
-    ::kernel::kunit::info(format_args!("    # {kunit_name}.location: {real_path}:{line}\n"));
+    ::kernel::kunit::info(fmt!("    # {kunit_name}.location: {real_path}:{line}\n"));
 
     /// The anchor where the test code body starts.
     #[allow(unused)]

-- 
2.50.0

[PATCH 7/9] rust: pin-init: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/kernel/init.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs
index 8d228c237954..aa3fc90d32d1 100644
--- a/rust/kernel/init.rs
+++ b/rust/kernel/init.rs
@@ -68,7 +68,7 @@
 //!
 //! ```rust,ignore
 //! # #![allow(unreachable_pub, clippy::disallowed_names)]
-//! use kernel::{prelude::*, types::Opaque};
+//! use kernel::{fmt, prelude::*, types::Opaque};
 //! use core::{ptr::addr_of_mut, marker::PhantomPinned, pin::Pin};
 //! # mod bindings {
 //! #     #![allow(non_camel_case_types)]
@@ -81,7 +81,7 @@
 //! # trait FromErrno {
 //! #     fn from_errno(errno: core::ffi::c_int) -> Error {
 //! #         // Dummy error that can be constructed outside the `kernel` crate.
-//! #         Error::from(core::fmt::Error)
+//! #         Error::from(fmt::Error)
 //! #     }
 //! # }
 //! # impl FromErrno for Error {}

-- 
2.50.0

Re: [PATCH 7/9] rust: pin-init: use `kernel::{fmt,prelude::fmt!}`

[Benno Lossin]

On Wed Jul 9, 2025 at 10:00 PM CEST, Tamir Duberstein wrote:
> Reduce coupling to implementation details of the formatting machinery by
> avoiding direct use for `core`'s formatting traits and macros.
>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>
> ---
>  rust/kernel/init.rs | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

I usually prefix patches to init.rs with `rust: init`. I'll fix it up
when picking the patch or Miguel can do it if he takes it:

Acked-by: Benno Lossin <lossin@kernel.org>

---
Cheers,
Benno

Re: [PATCH 7/9] rust: pin-init: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

On Wed, Jul 9, 2025 at 4:18 PM Benno Lossin <lossin@kernel.org> wrote:
>
> On Wed Jul 9, 2025 at 10:00 PM CEST, Tamir Duberstein wrote:
> > Reduce coupling to implementation details of the formatting machinery by
> > avoiding direct use for `core`'s formatting traits and macros.
> >
> > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> > Signed-off-by: Tamir Duberstein <tamird@gmail.com>
> > ---
> >  rust/kernel/init.rs | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
>
> I usually prefix patches to init.rs with `rust: init`. I'll fix it up
> when picking the patch or Miguel can do it if he takes it:
>
> Acked-by: Benno Lossin <lossin@kernel.org>

Actually, squinting at this patch more closely now, I think this isn't
what you had in mind. The comment says "Dummy error that can be
constructed outside the `kernel` crate." but the error now comes from
the kernel crate :(

Perhaps you could suggest a different modification that would both
meet the original intent and allow references to core::fmt to
disappear?

Re: [PATCH 7/9] rust: pin-init: use `kernel::{fmt,prelude::fmt!}`

[Benno Lossin]

On Wed Jul 9, 2025 at 11:01 PM CEST, Tamir Duberstein wrote:
> On Wed, Jul 9, 2025 at 4:18 PM Benno Lossin <lossin@kernel.org> wrote:
>>
>> On Wed Jul 9, 2025 at 10:00 PM CEST, Tamir Duberstein wrote:
>> > Reduce coupling to implementation details of the formatting machinery by
>> > avoiding direct use for `core`'s formatting traits and macros.
>> >
>> > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> > Reviewed-by: Alice Ryhl <aliceryhl@google.com>
>> > Signed-off-by: Tamir Duberstein <tamird@gmail.com>
>> > ---
>> >  rust/kernel/init.rs | 4 ++--
>> >  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> I usually prefix patches to init.rs with `rust: init`. I'll fix it up
>> when picking the patch or Miguel can do it if he takes it:
>>
>> Acked-by: Benno Lossin <lossin@kernel.org>
>
> Actually, squinting at this patch more closely now, I think this isn't
> what you had in mind. The comment says "Dummy error that can be
> constructed outside the `kernel` crate." but the error now comes from
> the kernel crate :(

It's a re-export, so the comment still holds.

> Perhaps you could suggest a different modification that would both
> meet the original intent and allow references to core::fmt to
> disappear?

The code comes from a time when `Error::from_errno` was `pub(crate)`,
but that was changed some time ago... Now we can just remove the
`FromErrno` trait entirely from that example. Feel free to do that in
this series or as a standalone patch.

---
Cheers,
Benno

Re: [PATCH 7/9] rust: pin-init: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

On Wed, Jul 9, 2025 at 5:58 PM Benno Lossin <lossin@kernel.org> wrote:
>
> On Wed Jul 9, 2025 at 11:01 PM CEST, Tamir Duberstein wrote:
> > On Wed, Jul 9, 2025 at 4:18 PM Benno Lossin <lossin@kernel.org> wrote:
> >>
> >> On Wed Jul 9, 2025 at 10:00 PM CEST, Tamir Duberstein wrote:
> >> > Reduce coupling to implementation details of the formatting machinery by
> >> > avoiding direct use for `core`'s formatting traits and macros.
> >> >
> >> > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> >> > Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> >> > Signed-off-by: Tamir Duberstein <tamird@gmail.com>
> >> > ---
> >> >  rust/kernel/init.rs | 4 ++--
> >> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> I usually prefix patches to init.rs with `rust: init`. I'll fix it up
> >> when picking the patch or Miguel can do it if he takes it:
> >>
> >> Acked-by: Benno Lossin <lossin@kernel.org>
> >
> > Actually, squinting at this patch more closely now, I think this isn't
> > what you had in mind. The comment says "Dummy error that can be
> > constructed outside the `kernel` crate." but the error now comes from
> > the kernel crate :(
>
> It's a re-export, so the comment still holds.
>
> > Perhaps you could suggest a different modification that would both
> > meet the original intent and allow references to core::fmt to
> > disappear?
>
> The code comes from a time when `Error::from_errno` was `pub(crate)`,
> but that was changed some time ago... Now we can just remove the
> `FromErrno` trait entirely from that example. Feel free to do that in
> this series or as a standalone patch.

Ack, sent https://lore.kernel.org/all/20250709-init-remove-old-workaround-v1-1-a922d32338d2@gmail.com/.

With that patch, this one can be dropped (since it is just a comment).

Re: [PATCH 7/9] rust: pin-init: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

On Wed, Jul 9, 2025 at 6:36 PM Tamir Duberstein <tamird@gmail.com> wrote:
>
>
> Ack, sent https://lore.kernel.org/all/20250709-init-remove-old-workaround-v1-1-a922d32338d2@gmail.com/.

Messed it up, sent v2:
https://lore.kernel.org/all/20250709-init-remove-old-workaround-v2-0-a3b1be8fd490@gmail.com/.

[PATCH 8/9] rust: seq_file: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/kernel/seq_file.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs
index 8f199b1a3bb1..59fbfc2473f8 100644
--- a/rust/kernel/seq_file.rs
+++ b/rust/kernel/seq_file.rs
@@ -4,7 +4,7 @@
 //!
 //! C header: [`include/linux/seq_file.h`](srctree/include/linux/seq_file.h)
 
-use crate::{bindings, c_str, types::NotThreadSafe, types::Opaque};
+use crate::{bindings, c_str, fmt, types::NotThreadSafe, types::Opaque};
 
 /// A utility for generating the contents of a seq file.
 #[repr(transparent)]
@@ -31,7 +31,7 @@ pub unsafe fn from_raw<'a>(ptr: *mut bindings::seq_file) -> &'a SeqFile {
 
     /// Used by the [`seq_print`] macro.
     #[inline]
-    pub fn call_printf(&self, args: core::fmt::Arguments<'_>) {
+    pub fn call_printf(&self, args: fmt::Arguments<'_>) {
         // SAFETY: Passing a void pointer to `Arguments` is valid for `%pA`.
         unsafe {
             bindings::seq_printf(
@@ -47,7 +47,7 @@ pub fn call_printf(&self, args: core::fmt::Arguments<'_>) {
 #[macro_export]
 macro_rules! seq_print {
     ($m:expr, $($arg:tt)+) => (
-        $m.call_printf(format_args!($($arg)+))
+        $m.call_printf($crate::prelude::fmt!($($arg)+))
     );
 }
 pub use seq_print;

-- 
2.50.0

Re: [PATCH 8/9] rust: seq_file: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

On Wed, Jul 9, 2025 at 4:00 PM Tamir Duberstein <tamird@gmail.com> wrote:
>
> Reduce coupling to implementation details of the formatting machinery by
> avoiding direct use for `core`'s formatting traits and macros.
>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>

Oops, forgot to include Christian Brauner. Christian, could you please
take a look?

MAINTAINERS entry being added in
https://lore.kernel.org/all/20250714124637.1905722-1-aliceryhl@google.com/.
(Thanks Alice!)

> ---
>  rust/kernel/seq_file.rs | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs
> index 8f199b1a3bb1..59fbfc2473f8 100644
> --- a/rust/kernel/seq_file.rs
> +++ b/rust/kernel/seq_file.rs
> @@ -4,7 +4,7 @@
>  //!
>  //! C header: [`include/linux/seq_file.h`](srctree/include/linux/seq_file.h)
>
> -use crate::{bindings, c_str, types::NotThreadSafe, types::Opaque};
> +use crate::{bindings, c_str, fmt, types::NotThreadSafe, types::Opaque};
>
>  /// A utility for generating the contents of a seq file.
>  #[repr(transparent)]
> @@ -31,7 +31,7 @@ pub unsafe fn from_raw<'a>(ptr: *mut bindings::seq_file) -> &'a SeqFile {
>
>      /// Used by the [`seq_print`] macro.
>      #[inline]
> -    pub fn call_printf(&self, args: core::fmt::Arguments<'_>) {
> +    pub fn call_printf(&self, args: fmt::Arguments<'_>) {
>          // SAFETY: Passing a void pointer to `Arguments` is valid for `%pA`.
>          unsafe {
>              bindings::seq_printf(
> @@ -47,7 +47,7 @@ pub fn call_printf(&self, args: core::fmt::Arguments<'_>) {
>  #[macro_export]
>  macro_rules! seq_print {
>      ($m:expr, $($arg:tt)+) => (
> -        $m.call_printf(format_args!($($arg)+))
> +        $m.call_printf($crate::prelude::fmt!($($arg)+))
>      );
>  }
>  pub use seq_print;
>
> --
> 2.50.0
>

[PATCH 9/9] rust: sync: use `kernel::{fmt,prelude::fmt!}`

[Tamir Duberstein]

Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 rust/kernel/sync/arc.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
index c7af0aa48a0a..b366260f56b3 100644
--- a/rust/kernel/sync/arc.rs
+++ b/rust/kernel/sync/arc.rs
@@ -18,14 +18,13 @@
 
 use crate::{
     alloc::{AllocError, Flags, KBox},
-    bindings,
+    bindings, fmt,
     init::InPlaceInit,
     try_init,
     types::{ForeignOwnable, Opaque},
 };
 use core::{
     alloc::Layout,
-    fmt,
     marker::PhantomData,
     mem::{ManuallyDrop, MaybeUninit},
     ops::{Deref, DerefMut},

-- 
2.50.0

Re: [PATCH 0/9] rust: use `kernel::{fmt,prelude::fmt!}`

[Benno Lossin]

On Wed Jul 9, 2025 at 9:59 PM CEST, Tamir Duberstein wrote:
> This is series 2a/5 of the migration to `core::ffi::CStr`[0].
> 20250704-core-cstr-prepare-v1-0-a91524037783@gmail.com.
>
> This series depends on the prior series[0] and is intended to go through
> the rust tree to reduce the number of release cycles required to
> complete the work.
>
> Subsystem maintainers: I would appreciate your `Acked-by`s so that this
> can be taken through Miguel's tree (where the other series must go).
>
> [0] https://lore.kernel.org/all/20250704-core-cstr-prepare-v1-0-a91524037783@gmail.com/
>
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>
> ---
> Tamir Duberstein (9):
>       gpu: nova-core: use `kernel::{fmt,prelude::fmt!}`
>       rust: alloc: use `kernel::{fmt,prelude::fmt!}`
>       rust: block: use `kernel::{fmt,prelude::fmt!}`
>       rust: device: use `kernel::{fmt,prelude::fmt!}`
>       rust: file: use `kernel::{fmt,prelude::fmt!}`
>       rust: kunit: use `kernel::{fmt,prelude::fmt!}`
>       rust: pin-init: use `kernel::{fmt,prelude::fmt!}`
>       rust: seq_file: use `kernel::{fmt,prelude::fmt!}`
>       rust: sync: use `kernel::{fmt,prelude::fmt!}`
>
>  drivers/block/rnull.rs               | 2 +-
>  drivers/gpu/nova-core/gpu.rs         | 3 +--
>  drivers/gpu/nova-core/regs/macros.rs | 6 +++---
>  rust/kernel/alloc/kbox.rs            | 2 +-
>  rust/kernel/alloc/kvec.rs            | 2 +-
>  rust/kernel/alloc/kvec/errors.rs     | 2 +-
>  rust/kernel/block/mq.rs              | 2 +-
>  rust/kernel/block/mq/gen_disk.rs     | 2 +-
>  rust/kernel/block/mq/raw_writer.rs   | 3 +--
>  rust/kernel/device.rs                | 6 +++---
>  rust/kernel/fs/file.rs               | 5 +++--
>  rust/kernel/init.rs                  | 4 ++--
>  rust/kernel/kunit.rs                 | 8 ++++----
>  rust/kernel/seq_file.rs              | 6 +++---
>  rust/kernel/sync/arc.rs              | 3 +--
>  scripts/rustdoc_test_gen.rs          | 2 +-
>  16 files changed, 28 insertions(+), 30 deletions(-)

For the entire series:

Reviewed-by: Benno Lossin <lossin@kernel.org>

---
Cheers,
Benno

Re: [PATCH 0/9] rust: use `kernel::{fmt,prelude::fmt!}`

[Danilo Krummrich]

On Wed Jul 9, 2025 at 9:59 PM CEST, Tamir Duberstein wrote:
> This is series 2a/5 of the migration to `core::ffi::CStr`[0].
> 20250704-core-cstr-prepare-v1-0-a91524037783@gmail.com.

For nova-core, alloc and device,

	Acked-by: Danilo Krummrich <dakr@kernel.org>