[ Upstream commit 0f580d5d3d9d9cd0953695cd32e43aac3a946338 ]

Commit fde578c86281 ("rust: alloc: replace aligned_size() with
Kmalloc::aligned_layout()") provides a public `aligned_layout` function
in `Kamlloc`, but not in `Cmalloc`, and thus uses of it will trigger an
error in `rusttest`.

Such a user appeared in the following commit 22ab0641b939 ("rust: drm:
ensure kmalloc() compatible Layout"):

    error[E0599]: no function or associated item named `aligned_layout` found for struct `alloc::allocator_test::Cmalloc` in the current scope
       --> rust/kernel/drm/device.rs:100:31
        |
    100 |         let layout = Kmalloc::aligned_layout(Layout::new::<Self>());
        |                               ^^^^^^^^^^^^^^ function or associated item not found in `Cmalloc`
        |
       ::: rust/kernel/alloc/allocator_test.rs:19:1
        |
    19  | pub struct Cmalloc;
        | ------------------ function or associated item `aligned_layout` not found for this struct

Thus add an equivalent one for `Cmalloc`.

Fixes: fde578c86281 ("rust: alloc: replace aligned_size() with Kmalloc::aligned_layout()")
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250816204215.2719559-1-ojeda@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit fde578c86281f27b182680c7642836a0dbbd0be7 ]

aligned_size() dates back to when Rust did support kmalloc() only, but
is now used in ReallocFunc::call() and hence for all allocators.

However, the additional padding applied by aligned_size() is only
required by the kmalloc() allocator backend.

Hence, replace aligned_size() with Kmalloc::aligned_layout() and use it
for the affected allocators, i.e. kmalloc() and kvmalloc(), only.

While at it, make Kmalloc::aligned_layout() public, such that Rust
abstractions, which have to call subsystem specific kmalloc() based
allocation primitives directly, can make use of it.

Fixes: 8a799831fc63 ("rust: alloc: implement `ReallocFunc`")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250731154919.4132-2-dakr@kernel.org
[ Remove `const` from Kmalloc::aligned_layout(). - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Add missing Markdown code span.

This was found using the Clippy `doc_markdown` lint, which we may want
to enable.

Fixes: dd09538fb409 ("rust: alloc: implement `Cmalloc` in module allocator_test")
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250324210359.1199574-5-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

For the Rust 1.87.0 release, Clippy was expected to warn with:

    error: use `core::ptr::eq` when comparing raw pointers
       --> rust/kernel/list.rs:438:12
        |
    438 |         if self.first == item {
        |            ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
        = note: `-D clippy::ptr-eq` implied by `-D warnings`
        = help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]`

However, a backport to relax a bit the `clippy::ptr_eq` finally landed,
and thus Clippy did not warn by the time the release happened.

Thus remove the `allow`s added back then, which were added just in case
the backport did not land in time.

See commit a39f30870927 ("rust: allow Rust 1.87.0's `clippy::ptr_eq`
lint") for details.

Link: https://github.com/rust-lang/rust/pull/140859 [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250520182125.806758-1-ojeda@kernel.org
[ Reworded for clarity. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Pull alloc updates from Danilo Krummrich:
 "Box:

   - Support for type coercion, e.g. 'Box<T>' to 'Box<dyn U>' if T
     implements U

  Vec:

   - Implement new methods (prerequisites for nova-core and binder)
      - Vec::truncate()
      - Vec::resize()
      - Vec::clear()
      - Vec::pop()
      - Vec::push_within_capacity()
         - New error type: PushError
      - Vec::drain_all()
      - Vec::retain()
      - Vec::remove()
         - New error type: RemoveError
      - Vec::insert_within_capacity
         - New error type: InsertError

   - Simplify Vec::push() using Vec::spare_capacity_mut()

   - Split Vec::set_len() into Vec::inc_len() and Vec::dec_len()
      - Add type invariant Vec::len() <= Vec::capacity
      - Simplify Vec::truncate() using Vec::dec_len()"

* tag 'alloc-next-v6.16-2025-05-13' of https://github.com/Rust-for-Linux/linux:
  rust: alloc: add Vec::insert_within_capacity
  rust: alloc: add Vec::remove
  rust: alloc: add Vec::retain
  rust: alloc: add Vec::drain_all
  rust: alloc: add Vec::push_within_capacity
  rust: alloc: add Vec::pop
  rust: alloc: add Vec::clear
  rust: alloc: replace `Vec::set_len` with `inc_len`
  rust: alloc: refactor `Vec::truncate` using `dec_len`
  rust: alloc: add `Vec::dec_len`
  rust: alloc: add Vec::len() <= Vec::capacity invariant
  rust: alloc: allow coercion from `Box<T>` to `Box<dyn U>` if T implements U
  rust: alloc: use `spare_capacity_mut` to reduce unsafe
  rust: alloc: add Vec::resize method
  rust: alloc: add Vec::truncate method
  rust: alloc: add missing invariant in Vec::set_len()

Pull XArray updates from Andreas Hindborg:
 "Introduce Rust support for the 'xarray' data structure:

   - Add a Rust abstraction for the 'xarray' data structure. This
     abstraction allows Rust code to leverage the 'xarray' to store
     types that implement 'ForeignOwnable'. This support is a dependency
     for memory backing feature of the Rust null block driver, which is
     waiting to be merged.

   - Set up an entry in MAINTAINERS for the XArray Rust support. Patches
     will go to the new Rust XArray tree and then via the Rust subsystem
     tree for now.

  'kernel' crate:

   - Allow 'ForeignOwnable' to carry information about the pointed-to
     type. This helps asserting alignment requirements for the pointer
     passed to the foreign language."

* tag 'rust-xarray-for-v6.16' of https://github.com/Rust-for-Linux/linux:
  MAINTAINERS: add entry for Rust XArray API
  rust: xarray: Add an abstraction for XArray
  rust: types: add `ForeignOwnable::PointedTo`

Some comments in Rust files use raw URLs (http://example.com) rather
than Markdown autolinks <URL>. This inconsistency makes the
documentation less uniform and harder to maintain.

This patch converts all remaining raw URLs in Rust code comments to use
the Markdown autolink format, maintaining consistency with the rest of
the codebase which already uses this style.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1153
Signed-off-by: Xizhe Yin <xizheyin@smail.nju.edu.cn>
Link: https://lore.kernel.org/r/509F0B66E3C1575D+20250407033441.5567-1-xizheyin@smail.nju.edu.cn
[ Used From form for Signed-off-by. Sorted tags. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This adds a variant of Vec::insert that does not allocate memory. This
makes it safe to use this function while holding a spinlock. Rust Binder
uses it for the range allocator fast path.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250502-vec-methods-v5-7-06d20ad9366f@google.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

This is needed by Rust Binder in the range allocator, and by upcoming
GPU drivers during firmware initialization.

Panics in the kernel are best avoided when possible, so an error is
returned if the index is out of bounds. An error type is used rather
than just returning Option<T> to let callers handle errors with ?.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250502-vec-methods-v5-6-06d20ad9366f@google.com
[ Remove `# Panics` section; `Vec::remove() handles the error properly.`
  - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

This adds a common Vec method called `retain` that removes all elements
that don't match a certain condition. Rust Binder uses it to find all
processes that match a given pid.

The stdlib retain method takes &T rather than &mut T and has a separate
retain_mut for the &mut T case. However, this is considered an API
mistake that can't be fixed now due to backwards compatibility. There's
no reason for us to repeat that mistake.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250502-vec-methods-v5-5-06d20ad9366f@google.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>