[PATCH v3 0/7] rust: use vertical import style and remove redundant imports

[PATCH v3 0/7] rust: use vertical import style and remove redundant imports

[Alvin Sun]

Adopt the vertical import style and drop redundant imports already
re-exported via `kernel::prelude`.

Changes include:
- Convert use statements to vertical import style in miscdevice,
  samples, doctest, and block/mq
- Remove imports covered by prelude and apply minor formatting

Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
Changes in v3:
- Add trailing // to last items and closing braces in block/mq imports
- Add rnull vertical import style
- Add doctest vertical import style
- Link to v2: https://lore.kernel.org/r/20260520-miscdev-use-format-v2-0-64dc48fc1345@linux.dev

Changes in v2:
- Reformat use statements and drop redundant imports in
  rust/kernel/block/mq
- Drop redundant imports in rust/kernel/miscdevice
- Link to v1: https://lore.kernel.org/r/20260519-miscdev-use-format-v1-0-11d526ba0edc@linux.dev

---
Alvin Sun (7):
      rust: miscdevice: use vertical import style
      samples: rust_misc_device: use vertical import style
      rust: miscdevice: remove redundant imports
      rust: block: mq: use vertical import style
      rust: block: mq: remove redundant imports and format
      rust: block: rnull: use vertical import style
      rust: doctest: use vertical import style

 drivers/block/rnull/configfs.rs    | 27 +++++++++++++++++++++------
 drivers/block/rnull/rnull.rs       | 15 +++++++++++----
 rust/kernel/block/mq/gen_disk.rs   | 24 ++++++++++++++++++------
 rust/kernel/block/mq/operations.rs | 14 ++++++++++----
 rust/kernel/block/mq/request.rs    | 16 +++++++++++-----
 rust/kernel/block/mq/tag_set.rs    | 28 ++++++++++++++--------------
 rust/kernel/miscdevice.rs          | 23 +++++++++++++++++------
 samples/rust/rust_misc_device.rs   | 34 ++++++++++++++++++++++++++++------
 scripts/rustdoc_test_gen.rs        | 11 +++++++++--
 9 files changed, 139 insertions(+), 53 deletions(-)
---
base-commit: 5200f5f493f79f14bbdc349e402a40dfb32f23c8
change-id: 20260519-miscdev-use-format-9ab7e83b1c11

Best regards,
-- 
Alvin Sun <alvin.sun@linux.dev>

[PATCH v3 1/7] rust: miscdevice: use vertical import style

[Alvin Sun]

Convert `use` imports to vertical layout for better readability and
maintainability.

Reviewed-by: Onur Özkan <work@onurozkan.dev>
Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 rust/kernel/miscdevice.rs | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs
index c3c2052c92069..05a6b6b9770f2 100644
--- a/rust/kernel/miscdevice.rs
+++ b/rust/kernel/miscdevice.rs
@@ -11,16 +11,38 @@
 use crate::{
     bindings,
     device::Device,
-    error::{to_result, Error, Result, VTABLE_DEFAULT_ERROR},
-    ffi::{c_int, c_long, c_uint, c_ulong},
-    fs::{File, Kiocb},
-    iov::{IovIterDest, IovIterSource},
+    error::{
+        to_result,
+        Error,
+        Result,
+        VTABLE_DEFAULT_ERROR, //
+    },
+    ffi::{
+        c_int,
+        c_long,
+        c_uint,
+        c_ulong, //
+    },
+    fs::{
+        File,
+        Kiocb, //
+    },
+    iov::{
+        IovIterDest,
+        IovIterSource, //
+    },
     mm::virt::VmaNew,
     prelude::*,
     seq_file::SeqFile,
-    types::{ForeignOwnable, Opaque},
+    types::{
+        ForeignOwnable,
+        Opaque, //
+    },
+};
+use core::{
+    marker::PhantomData,
+    pin::Pin, //
 };
-use core::{marker::PhantomData, pin::Pin};
 
 /// Options for creating a misc device.
 #[derive(Copy, Clone)]

-- 
2.43.0

[PATCH v3 2/7] samples: rust_misc_device: use vertical import style

[Alvin Sun]

Convert `use` imports to vertical layout for better readability and
maintainability.

Reviewed-by: Onur Özkan <work@onurozkan.dev>
Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 samples/rust/rust_misc_device.rs | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/samples/rust/rust_misc_device.rs b/samples/rust/rust_misc_device.rs
index 87a1fe63533ae..41e26c825060b 100644
--- a/samples/rust/rust_misc_device.rs
+++ b/samples/rust/rust_misc_device.rs
@@ -97,14 +97,36 @@
 
 use kernel::{
     device::Device,
-    fs::{File, Kiocb},
-    ioctl::{_IO, _IOC_SIZE, _IOR, _IOW},
-    iov::{IovIterDest, IovIterSource},
-    miscdevice::{MiscDevice, MiscDeviceOptions, MiscDeviceRegistration},
+    fs::{
+        File,
+        Kiocb, //
+    },
+    ioctl::{
+        _IO,
+        _IOC_SIZE,
+        _IOR,
+        _IOW, //
+    },
+    iov::{
+        IovIterDest,
+        IovIterSource, //
+    },
+    miscdevice::{
+        MiscDevice,
+        MiscDeviceOptions,
+        MiscDeviceRegistration, //
+    },
     new_mutex,
     prelude::*,
-    sync::{aref::ARef, Mutex},
-    uaccess::{UserSlice, UserSliceReader, UserSliceWriter},
+    sync::{
+        aref::ARef,
+        Mutex, //
+    },
+    uaccess::{
+        UserSlice,
+        UserSliceReader,
+        UserSliceWriter, //
+    },
 };
 
 const RUST_MISC_DEV_HELLO: u32 = _IO('|' as u32, 0x80);

-- 
2.43.0

[PATCH v3 3/7] rust: miscdevice: remove redundant imports

[Alvin Sun]

Drop `Error`, `Result`, `Pin`, `c_int`, `c_long`, `c_uint`, and
`c_ulong` imports already provided by `kernel::prelude`.

Reviewed-by: Onur Özkan <work@onurozkan.dev>
Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 rust/kernel/miscdevice.rs | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs
index 05a6b6b9770f2..83ce50def5ac9 100644
--- a/rust/kernel/miscdevice.rs
+++ b/rust/kernel/miscdevice.rs
@@ -13,16 +13,8 @@
     device::Device,
     error::{
         to_result,
-        Error,
-        Result,
         VTABLE_DEFAULT_ERROR, //
     },
-    ffi::{
-        c_int,
-        c_long,
-        c_uint,
-        c_ulong, //
-    },
     fs::{
         File,
         Kiocb, //
@@ -39,10 +31,7 @@
         Opaque, //
     },
 };
-use core::{
-    marker::PhantomData,
-    pin::Pin, //
-};
+use core::marker::PhantomData;
 
 /// Options for creating a misc device.
 #[derive(Copy, Clone)]

-- 
2.43.0

[PATCH v3 4/7] rust: block: mq: use vertical import style

[Alvin Sun]

Convert `use` imports to vertical layout for better readability and
maintainability.

Reviewed-by: Onur Özkan <work@onurozkan.dev>
Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 rust/kernel/block/mq/gen_disk.rs   | 21 +++++++++++++++++----
 rust/kernel/block/mq/operations.rs | 17 +++++++++++++----
 rust/kernel/block/mq/request.rs    | 14 ++++++++++----
 rust/kernel/block/mq/tag_set.rs    | 24 +++++++++++++++++++-----
 4 files changed, 59 insertions(+), 17 deletions(-)

diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index 912cb805caf51..aac8ece10ae7c 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -7,14 +7,27 @@
 
 use crate::{
     bindings,
-    block::mq::{Operations, TagSet},
-    error::{self, from_err_ptr, Result},
-    fmt::{self, Write},
+    block::mq::{
+        Operations,
+        TagSet, //
+    },
+    error::{
+        self,
+        from_err_ptr,
+        Result, //
+    },
+    fmt::{
+        self,
+        Write, //
+    },
     prelude::*,
     static_lock_class,
     str::NullTerminatedFormatter,
     sync::Arc,
-    types::{ForeignOwnable, ScopeGuard},
+    types::{
+        ForeignOwnable,
+        ScopeGuard, //
+    }, //
 };
 
 /// A builder for [`GenDisk`].
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 8ad46129a52c4..187b0b7791db9 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -6,11 +6,20 @@
 
 use crate::{
     bindings,
-    block::mq::{request::RequestDataWrapper, Request},
-    error::{from_result, Result},
+    block::mq::{
+        request::RequestDataWrapper,
+        Request, //
+    },
+    error::{
+        from_result,
+        Result, //
+    },
     prelude::*,
-    sync::{aref::ARef, Refcount},
-    types::ForeignOwnable,
+    sync::{
+        aref::ARef,
+        Refcount, //
+    },
+    types::ForeignOwnable, //
 };
 use core::marker::PhantomData;
 
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index ce3e30c81cb5e..66254d02bba65 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -9,13 +9,19 @@
     block::mq::Operations,
     error::Result,
     sync::{
-        aref::{ARef, AlwaysRefCounted},
+        aref::{
+            ARef,
+            AlwaysRefCounted, //
+        },
         atomic::Relaxed,
-        Refcount,
+        Refcount, //
     },
-    types::Opaque,
+    types::Opaque, //
+};
+use core::{
+    marker::PhantomData,
+    ptr::NonNull, //
 };
-use core::{marker::PhantomData, ptr::NonNull};
 
 /// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
 ///
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index dae9df408a862..c1fd3e047af50 100644
--- a/rust/kernel/block/mq/tag_set.rs
+++ b/rust/kernel/block/mq/tag_set.rs
@@ -8,13 +8,27 @@
 
 use crate::{
     bindings,
-    block::mq::{operations::OperationsVTable, request::RequestDataWrapper, Operations},
-    error::{self, Result},
+    block::mq::{
+        operations::OperationsVTable,
+        request::RequestDataWrapper,
+        Operations, //
+    },
+    error::{
+        self,
+        Result, //
+    },
     prelude::try_pin_init,
-    types::Opaque,
+    types::Opaque, //
+};
+use core::{
+    convert::TryInto,
+    marker::PhantomData, //
+};
+use pin_init::{
+    pin_data,
+    pinned_drop,
+    PinInit, //
 };
-use core::{convert::TryInto, marker::PhantomData};
-use pin_init::{pin_data, pinned_drop, PinInit};
 
 /// A wrapper for the C `struct blk_mq_tag_set`.
 ///

-- 
2.43.0

[PATCH v3 5/7] rust: block: mq: remove redundant imports and format

[Alvin Sun]

Drop `Result`, `Pin`, `pin_data`, `pinned_drop`, `PinInit`, and
`try_pin_init` imports already provided by `kernel::prelude`.

Simplify `error` imports and flatten parameters formatting.

Reviewed-by: Onur Özkan <work@onurozkan.dev>
Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 rust/kernel/block/mq/gen_disk.rs   |  7 +++----
 rust/kernel/block/mq/operations.rs |  5 +----
 rust/kernel/block/mq/request.rs    |  2 +-
 rust/kernel/block/mq/tag_set.rs    | 22 ++++------------------
 4 files changed, 9 insertions(+), 27 deletions(-)

diff --git a/rust/kernel/block/mq/gen_disk.rs b/rust/kernel/block/mq/gen_disk.rs
index aac8ece10ae7c..b9653537cb44f 100644
--- a/rust/kernel/block/mq/gen_disk.rs
+++ b/rust/kernel/block/mq/gen_disk.rs
@@ -12,9 +12,8 @@
         TagSet, //
     },
     error::{
-        self,
         from_err_ptr,
-        Result, //
+        to_result, //
     },
     fmt::{
         self,
@@ -67,7 +66,7 @@ pub fn rotational(mut self, rotational: bool) -> Self {
     /// and that it is a power of two.
     pub fn validate_block_size(size: u32) -> Result {
         if !(512..=bindings::PAGE_SIZE as u32).contains(&size) || !size.is_power_of_two() {
-            Err(error::code::EINVAL)
+            Err(EINVAL)
         } else {
             Ok(())
         }
@@ -177,7 +176,7 @@ pub fn build<T: Operations>(
         // operation, so we will not race.
         unsafe { bindings::set_capacity(gendisk, self.capacity_sectors) };
 
-        crate::error::to_result(
+        to_result(
             // SAFETY: `gendisk` points to a valid and initialized instance of
             // `struct gendisk`.
             unsafe {
diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs
index 187b0b7791db9..0343069b373c7 100644
--- a/rust/kernel/block/mq/operations.rs
+++ b/rust/kernel/block/mq/operations.rs
@@ -10,10 +10,7 @@
         request::RequestDataWrapper,
         Request, //
     },
-    error::{
-        from_result,
-        Result, //
-    },
+    error::from_result,
     prelude::*,
     sync::{
         aref::ARef,
diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs
index 66254d02bba65..6115f9aec2285 100644
--- a/rust/kernel/block/mq/request.rs
+++ b/rust/kernel/block/mq/request.rs
@@ -7,7 +7,7 @@
 use crate::{
     bindings,
     block::mq::Operations,
-    error::Result,
+    prelude::*,
     sync::{
         aref::{
             ARef,
diff --git a/rust/kernel/block/mq/tag_set.rs b/rust/kernel/block/mq/tag_set.rs
index c1fd3e047af50..df3f90bfbb817 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::{
@@ -13,22 +11,14 @@
         request::RequestDataWrapper,
         Operations, //
     },
-    error::{
-        self,
-        Result, //
-    },
-    prelude::try_pin_init,
+    error::to_result,
+    prelude::*,
     types::Opaque, //
 };
 use core::{
     convert::TryInto,
     marker::PhantomData, //
 };
-use pin_init::{
-    pin_data,
-    pinned_drop,
-    PinInit, //
-};
 
 /// A wrapper for the C `struct blk_mq_tag_set`.
 ///
@@ -47,11 +37,7 @@ pub struct TagSet<T: Operations> {
 
 impl<T: Operations> TagSet<T> {
     /// Try to create a new tag set
-    pub fn new(
-        nr_hw_queues: u32,
-        num_tags: u32,
-        num_maps: u32,
-    ) -> impl PinInit<Self, error::Error> {
+    pub fn new(nr_hw_queues: u32, num_tags: u32, num_maps: u32) -> impl PinInit<Self, Error> {
         let tag_set: bindings::blk_mq_tag_set = pin_init::zeroed();
         let tag_set: Result<_> = core::mem::size_of::<RequestDataWrapper>()
             .try_into()
@@ -77,7 +63,7 @@ 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())})
+                to_result( unsafe { bindings::blk_mq_alloc_tag_set(tag_set.get())})
             }),
             _p: PhantomData,
         })

-- 
2.43.0

[PATCH v3 6/7] rust: block: rnull: use vertical import style

[Alvin Sun]

Convert `use` imports to vertical layout for better readability and
maintainability.

Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 drivers/block/rnull/configfs.rs | 27 +++++++++++++++++++++------
 drivers/block/rnull/rnull.rs    | 15 +++++++++++----
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/drivers/block/rnull/configfs.rs b/drivers/block/rnull/configfs.rs
index 7c2eb5c0b7228..c10a55fc58948 100644
--- a/drivers/block/rnull/configfs.rs
+++ b/drivers/block/rnull/configfs.rs
@@ -1,16 +1,31 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use super::{NullBlkDevice, THIS_MODULE};
+use super::{
+    NullBlkDevice,
+    THIS_MODULE, //
+};
 use kernel::{
-    block::mq::gen_disk::{GenDisk, GenDiskBuilder},
-    configfs::{self, AttributeOperations},
+    block::mq::gen_disk::{
+        GenDisk,
+        GenDiskBuilder, //
+    },
+    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, //
 };
 
 pub(crate) fn subsystem() -> impl PinInit<kernel::configfs::Subsystem<Config>, Error> {
diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs
index 0ca8715febe83..13048cea8bb0d 100644
--- a/drivers/block/rnull/rnull.rs
+++ b/drivers/block/rnull/rnull.rs
@@ -10,12 +10,19 @@
         self,
         mq::{
             self,
-            gen_disk::{self, GenDisk},
-            Operations, TagSet,
-        },
+            gen_disk::{
+                self,
+                GenDisk, //
+            },
+            Operations,
+            TagSet, //
+        }, //
     },
     prelude::*,
-    sync::{aref::ARef, Arc},
+    sync::{
+        aref::ARef,
+        Arc, //
+    }, //
 };
 
 module! {

-- 
2.43.0

[PATCH v3 7/7] rust: doctest: use vertical import style

[Alvin Sun]

Convert `use` imports to vertical layout for better readability and
maintainability.

Signed-off-by: Alvin Sun <alvin.sun@linux.dev>
---
 scripts/rustdoc_test_gen.rs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs
index d61a77219a8c2..ee76e96b41eea 100644
--- a/scripts/rustdoc_test_gen.rs
+++ b/scripts/rustdoc_test_gen.rs
@@ -31,8 +31,15 @@
 use std::{
     fs,
     fs::File,
-    io::{BufWriter, Read, Write},
-    path::{Path, PathBuf},
+    io::{
+        BufWriter,
+        Read,
+        Write, //
+    },
+    path::{
+        Path,
+        PathBuf, //
+    }, //
 };
 
 /// Find the real path to the original file based on the `file` portion of the test name.

-- 
2.43.0