[PATCH 1/2] rust: alloc: cleanup imports and use "kernel vertical" style

[PATCH 1/2] rust: alloc: cleanup imports and use "kernel vertical" style

[Danilo Krummrich]

Change all imports in the alloc module to use the "kernel vertical"
import style [1].

While at it, drop unnecessary imports covered by prelude::*.

Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/alloc/allocator.rs      | 27 ++++++++++----
 rust/kernel/alloc/allocator/iter.rs |  8 +++-
 rust/kernel/alloc/kbox.rs           | 58 ++++++++++++++++++++---------
 rust/kernel/alloc/kvec.rs           | 49 +++++++++++++++++-------
 rust/kernel/alloc/kvec/errors.rs    |  6 ++-
 rust/kernel/alloc/layout.rs         |  5 ++-
 6 files changed, 109 insertions(+), 44 deletions(-)

diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
index 63bfb91b3671..af20332d59f7 100644
--- a/rust/kernel/alloc/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -8,14 +8,25 @@
 //!
 //! Reference: <https://docs.kernel.org/core-api/memory-allocation.html>
 
-use super::Flags;
-use core::alloc::Layout;
-use core::ptr;
-use core::ptr::NonNull;
-
-use crate::alloc::{AllocError, Allocator, NumaNode};
-use crate::bindings;
-use crate::page;
+use super::{
+    AllocError,
+    Allocator,
+    Flags,
+    NumaNode, //
+};
+
+use crate::{
+    bindings,
+    page, //
+};
+
+use core::{
+    alloc::Layout,
+    ptr::{
+        self,
+        NonNull, //
+    }, //
+};
 
 const ARCH_KMALLOC_MINALIGN: usize = bindings::ARCH_KMALLOC_MINALIGN;
 
diff --git a/rust/kernel/alloc/allocator/iter.rs b/rust/kernel/alloc/allocator/iter.rs
index e0a70b7a744a..02fda3ea5cae 100644
--- a/rust/kernel/alloc/allocator/iter.rs
+++ b/rust/kernel/alloc/allocator/iter.rs
@@ -1,9 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
 
 use super::Vmalloc;
+
 use crate::page;
-use core::marker::PhantomData;
-use core::ptr::NonNull;
+
+use core::{
+    marker::PhantomData,
+    ptr::NonNull, //
+};
 
 /// An [`Iterator`] of [`page::BorrowedPage`] items owned by a [`Vmalloc`] allocation.
 ///
diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs
index bd6da02c7ab8..0de45d8d235a 100644
--- a/rust/kernel/alloc/kbox.rs
+++ b/rust/kernel/alloc/kbox.rs
@@ -3,24 +3,46 @@
 //! Implementation of [`Box`].
 
 #[allow(unused_imports)] // Used in doc comments.
-use super::allocator::{KVmalloc, Kmalloc, Vmalloc, VmallocPageIter};
-use super::{AllocError, Allocator, Flags, NumaNode};
-use core::alloc::Layout;
-use core::borrow::{Borrow, BorrowMut};
-use core::marker::PhantomData;
-use core::mem::ManuallyDrop;
-use core::mem::MaybeUninit;
-use core::ops::{Deref, DerefMut};
-use core::pin::Pin;
-use core::ptr::NonNull;
-use core::result::Result;
-
-use crate::ffi::c_void;
-use crate::fmt;
-use crate::init::InPlaceInit;
-use crate::page::AsPageIter;
-use crate::types::ForeignOwnable;
-use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption};
+use super::{
+    allocator::{
+        KVmalloc,
+        Kmalloc,
+        Vmalloc,
+        VmallocPageIter, //
+    },
+    AllocError,
+    Allocator,
+    Flags,
+    NumaNode, //
+};
+
+use crate::{
+    fmt,
+    page::AsPageIter,
+    prelude::*,
+    types::ForeignOwnable, //
+};
+
+use core::{
+    alloc::Layout,
+    borrow::{
+        Borrow,
+        BorrowMut, //
+    },
+    marker::PhantomData,
+    mem::{
+        ManuallyDrop,
+        MaybeUninit, //
+    },
+    ops::{
+        Deref,
+        DerefMut, //
+    },
+    ptr::NonNull,
+    result::Result, //
+};
+
+use pin_init::ZeroableOption;
 
 /// The kernel's [`Box`] type -- a heap allocation for a single value of type `T`.
 ///
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs
index 6438385e4322..4340525f2672 100644
--- a/rust/kernel/alloc/kvec.rs
+++ b/rust/kernel/alloc/kvec.rs
@@ -3,29 +3,52 @@
 //! Implementation of [`Vec`].
 
 use super::{
-    allocator::{KVmalloc, Kmalloc, Vmalloc, VmallocPageIter},
+    allocator::{
+        KVmalloc,
+        Kmalloc,
+        Vmalloc,
+        VmallocPageIter, //
+    },
     layout::ArrayLayout,
-    AllocError, Allocator, Box, Flags, NumaNode,
+    AllocError,
+    Allocator,
+    Box,
+    Flags,
+    NumaNode, //
 };
+
 use crate::{
     fmt,
     page::{
         AsPageIter,
         PAGE_SIZE, //
-    },
+    }, //
 };
+
 use core::{
-    borrow::{Borrow, BorrowMut},
+    borrow::{
+        Borrow,
+        BorrowMut, //
+    },
     marker::PhantomData,
-    mem::{ManuallyDrop, MaybeUninit},
-    ops::Deref,
-    ops::DerefMut,
-    ops::Index,
-    ops::IndexMut,
-    ptr,
-    ptr::NonNull,
-    slice,
-    slice::SliceIndex,
+    mem::{
+        ManuallyDrop,
+        MaybeUninit, //
+    },
+    ops::{
+        Deref,
+        DerefMut,
+        Index,
+        IndexMut, //
+    },
+    ptr::{
+        self,
+        NonNull, //
+    },
+    slice::{
+        self,
+        SliceIndex, //
+    }, //
 };
 
 mod errors;
diff --git a/rust/kernel/alloc/kvec/errors.rs b/rust/kernel/alloc/kvec/errors.rs
index 985c5f2c3962..aaca6446516a 100644
--- a/rust/kernel/alloc/kvec/errors.rs
+++ b/rust/kernel/alloc/kvec/errors.rs
@@ -2,8 +2,10 @@
 
 //! Errors for the [`Vec`] type.
 
-use kernel::fmt;
-use kernel::prelude::*;
+use crate::{
+    fmt,
+    prelude::*, //
+};
 
 /// Error type for [`Vec::push_within_capacity`].
 pub struct PushError<T>(pub T);
diff --git a/rust/kernel/alloc/layout.rs b/rust/kernel/alloc/layout.rs
index 9f8be72feb7a..b629da4aed07 100644
--- a/rust/kernel/alloc/layout.rs
+++ b/rust/kernel/alloc/layout.rs
@@ -4,7 +4,10 @@
 //!
 //! Custom layout types extending or improving [`Layout`].
 
-use core::{alloc::Layout, marker::PhantomData};
+use core::{
+    alloc::Layout,
+    marker::PhantomData, //
+};
 
 /// Error when constructing an [`ArrayLayout`].
 pub struct LayoutError;

base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
-- 
2.54.0

[PATCH 2/2] rust: alloc: cleanup doctest imports to "kernel vertical" style

[Danilo Krummrich]

Change all imports in the alloc module's doctests to use the "kernel
vertical" import style [1].

While at it, drop imports that are automatically included in doctests.

Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/alloc/allocator.rs |  7 +++++--
 rust/kernel/alloc/kbox.rs      | 17 +++++++++++------
 rust/kernel/alloc/kvec.rs      | 10 +++++++---
 rust/kernel/alloc/layout.rs    |  5 ++++-
 4 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
index af20332d59f7..562e41925ada 100644
--- a/rust/kernel/alloc/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -174,8 +174,11 @@ impl Vmalloc {
     /// # Examples
     ///
     /// ```
-    /// # use core::ptr::{NonNull, from_mut};
-    /// # use kernel::{page, prelude::*};
+    /// # use core::ptr::{
+    /// #     from_mut,
+    /// #     NonNull, //
+    /// # };
+    /// # use kernel::page;
     /// use kernel::alloc::allocator::Vmalloc;
     ///
     /// let mut vbox = VBox::<[u8; page::PAGE_SIZE]>::new_uninit(GFP_KERNEL)?;
diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs
index 0de45d8d235a..146d1b5e20bb 100644
--- a/rust/kernel/alloc/kbox.rs
+++ b/rust/kernel/alloc/kbox.rs
@@ -296,7 +296,10 @@ pub fn pin(x: T, flags: Flags) -> Result<Pin<Box<T, A>>, AllocError>
     /// # Examples
     ///
     /// ```
-    /// use kernel::sync::{new_spinlock, SpinLock};
+    /// use kernel::sync::{
+    ///     new_spinlock,
+    ///     SpinLock, //
+    /// };
     ///
     /// struct Inner {
     ///     a: u32,
@@ -589,7 +592,6 @@ fn deref_mut(&mut self) -> &mut T {
 ///
 /// ```
 /// # use core::borrow::Borrow;
-/// # use kernel::alloc::KBox;
 /// struct Foo<B: Borrow<u32>>(B);
 ///
 /// // Owned instance.
@@ -617,7 +619,6 @@ fn borrow(&self) -> &T {
 ///
 /// ```
 /// # use core::borrow::BorrowMut;
-/// # use kernel::alloc::KBox;
 /// struct Foo<B: BorrowMut<u32>>(B);
 ///
 /// // Owned instance.
@@ -682,9 +683,13 @@ fn drop(&mut self) {
 /// # Examples
 ///
 /// ```
-/// # use kernel::prelude::*;
-/// use kernel::alloc::allocator::VmallocPageIter;
-/// use kernel::page::{AsPageIter, PAGE_SIZE};
+/// use kernel::{
+///     alloc::allocator::VmallocPageIter,
+///     page::{
+///         AsPageIter,
+///         PAGE_SIZE, //
+///     }, //
+/// };
 ///
 /// let mut vbox = VBox::new((), GFP_KERNEL)?;
 ///
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs
index 4340525f2672..932caa740327 100644
--- a/rust/kernel/alloc/kvec.rs
+++ b/rust/kernel/alloc/kvec.rs
@@ -1169,9 +1169,13 @@ fn into_iter(self) -> Self::IntoIter {
 /// # Examples
 ///
 /// ```
-/// # use kernel::prelude::*;
-/// use kernel::alloc::allocator::VmallocPageIter;
-/// use kernel::page::{AsPageIter, PAGE_SIZE};
+/// use kernel::{
+///     alloc::allocator::VmallocPageIter,
+///     page::{
+///         AsPageIter,
+///         PAGE_SIZE, //
+///     }, //
+/// };
 ///
 /// let mut vec = VVec::<u8>::new();
 ///
diff --git a/rust/kernel/alloc/layout.rs b/rust/kernel/alloc/layout.rs
index b629da4aed07..62a459c66baf 100644
--- a/rust/kernel/alloc/layout.rs
+++ b/rust/kernel/alloc/layout.rs
@@ -50,7 +50,10 @@ pub const fn empty() -> Self {
     /// # Examples
     ///
     /// ```
-    /// # use kernel::alloc::layout::{ArrayLayout, LayoutError};
+    /// # use kernel::alloc::layout::{
+    /// #     ArrayLayout,
+    /// #     LayoutError, //
+    /// # };
     /// let layout = ArrayLayout::<i32>::new(15)?;
     /// assert_eq!(layout.len(), 15);
     ///
-- 
2.54.0

Re: [PATCH 2/2] rust: alloc: cleanup doctest imports to "kernel vertical" style

[Eliot Courtney]

On Tue May 12, 2026 at 6:41 AM JST, Danilo Krummrich wrote:
> Change all imports in the alloc module's doctests to use the "kernel
> vertical" import style [1].
>
> While at it, drop imports that are automatically included in doctests.
>
> Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> ---

Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>

Re: [PATCH 2/2] rust: alloc: cleanup doctest imports to "kernel vertical" style

[Gary Guo]

On Mon May 11, 2026 at 10:41 PM BST, Danilo Krummrich wrote:
> Change all imports in the alloc module's doctests to use the "kernel
> vertical" import style [1].
>
> While at it, drop imports that are automatically included in doctests.
>
> Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> ---
>  rust/kernel/alloc/allocator.rs |  7 +++++--
>  rust/kernel/alloc/kbox.rs      | 17 +++++++++++------
>  rust/kernel/alloc/kvec.rs      | 10 +++++++---
>  rust/kernel/alloc/layout.rs    |  5 ++++-
>  4 files changed, 27 insertions(+), 12 deletions(-)
>
> diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
> index af20332d59f7..562e41925ada 100644
> --- a/rust/kernel/alloc/allocator.rs
> +++ b/rust/kernel/alloc/allocator.rs
> @@ -174,8 +174,11 @@ impl Vmalloc {
>      /// # Examples
>      ///
>      /// ```
> -    /// # use core::ptr::{NonNull, from_mut};
> -    /// # use kernel::{page, prelude::*};
> +    /// # use core::ptr::{
> +    /// #     from_mut,
> +    /// #     NonNull, //
> +    /// # };

I thought the consensus was that hidden lines don't need to use vertical import
style. They're not prone to merge conflict, and it can be unnecessarily sparse
especially if there're a lot of imports. Did I misremember it?

Best,
Gary

Re: [PATCH 2/2] rust: alloc: cleanup doctest imports to "kernel vertical" style

[Danilo Krummrich]

On Tue May 12, 2026 at 4:11 PM CEST, Gary Guo wrote:
> On Mon May 11, 2026 at 10:41 PM BST, Danilo Krummrich wrote:
>> @@ -174,8 +174,11 @@ impl Vmalloc {
>>      /// # Examples
>>      ///
>>      /// ```
>> -    /// # use core::ptr::{NonNull, from_mut};
>> -    /// # use kernel::{page, prelude::*};
>> +    /// # use core::ptr::{
>> +    /// #     from_mut,
>> +    /// #     NonNull, //
>> +    /// # };
>
> I thought the consensus was that hidden lines don't need to use vertical import
> style.

Don't need to, but still can; I generally prefer to keep it consistent.

We can drop the - for doc-comments - unnecessary '//' though, which my muscle
memory inserted regardless. :)

Re: [PATCH 1/2] rust: alloc: cleanup imports and use "kernel vertical" style

[Eliot Courtney]

On Tue May 12, 2026 at 6:41 AM JST, Danilo Krummrich wrote:
> Change all imports in the alloc module to use the "kernel vertical"
> import style [1].
>
> While at it, drop unnecessary imports covered by prelude::*.
>
> Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> ---

There are some non-vertical style imports in rust/kernel/alloc.rs,
should those be changed too?

> --- a/rust/kernel/alloc/kbox.rs
> +++ b/rust/kernel/alloc/kbox.rs
> @@ -3,24 +3,46 @@
>  //! Implementation of [`Box`].
>  
>  #[allow(unused_imports)] // Used in doc comments.
> -use super::allocator::{KVmalloc, Kmalloc, Vmalloc, VmallocPageIter};
> -use super::{AllocError, Allocator, Flags, NumaNode};
> -use core::alloc::Layout;
> -use core::borrow::{Borrow, BorrowMut};
> -use core::marker::PhantomData;
> -use core::mem::ManuallyDrop;
> -use core::mem::MaybeUninit;
> -use core::ops::{Deref, DerefMut};
> -use core::pin::Pin;
> -use core::ptr::NonNull;
> -use core::result::Result;
> -
> -use crate::ffi::c_void;
> -use crate::fmt;
> -use crate::init::InPlaceInit;
> -use crate::page::AsPageIter;
> -use crate::types::ForeignOwnable;
> -use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption};
> +use super::{
> +    allocator::{
> +        KVmalloc,
> +        Kmalloc,
> +        Vmalloc,
> +        VmallocPageIter, //
> +    },
> +    AllocError,
> +    Allocator,
> +    Flags,
> +    NumaNode, //
> +};

This changes the scope of `allow(unused_imports)`. Is this intentional?

Both nits so:

Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>

Re: [PATCH 1/2] rust: alloc: cleanup imports and use "kernel vertical" style

[Danilo Krummrich]

On Tue May 12, 2026 at 3:46 PM CEST, Eliot Courtney wrote:
> On Tue May 12, 2026 at 6:41 AM JST, Danilo Krummrich wrote:
>> Change all imports in the alloc module to use the "kernel vertical"
>> import style [1].
>>
>> While at it, drop unnecessary imports covered by prelude::*.
>>
>> Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
>> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
>> ---
>
> There are some non-vertical style imports in rust/kernel/alloc.rs,
> should those be changed too?

Yes, thanks for catching this, and the one below.

>> --- a/rust/kernel/alloc/kbox.rs
>> +++ b/rust/kernel/alloc/kbox.rs
>> @@ -3,24 +3,46 @@
>>  //! Implementation of [`Box`].
>>  
>>  #[allow(unused_imports)] // Used in doc comments.
>> -use super::allocator::{KVmalloc, Kmalloc, Vmalloc, VmallocPageIter};
>> -use super::{AllocError, Allocator, Flags, NumaNode};
>> -use core::alloc::Layout;
>> -use core::borrow::{Borrow, BorrowMut};
>> -use core::marker::PhantomData;
>> -use core::mem::ManuallyDrop;
>> -use core::mem::MaybeUninit;
>> -use core::ops::{Deref, DerefMut};
>> -use core::pin::Pin;
>> -use core::ptr::NonNull;
>> -use core::result::Result;
>> -
>> -use crate::ffi::c_void;
>> -use crate::fmt;
>> -use crate::init::InPlaceInit;
>> -use crate::page::AsPageIter;
>> -use crate::types::ForeignOwnable;
>> -use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption};
>> +use super::{
>> +    allocator::{
>> +        KVmalloc,
>> +        Kmalloc,
>> +        Vmalloc,
>> +        VmallocPageIter, //
>> +    },
>> +    AllocError,
>> +    Allocator,
>> +    Flags,
>> +    NumaNode, //
>> +};
>
> This changes the scope of `allow(unused_imports)`. Is this intentional?
>
> Both nits so:
>
> Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>