Commit 2dedf83d authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

rust: dma: require mutable reference for as_slice_mut() and write() 



Given the safety requirements of as_slice_mut() and write() taking an
immutable reference is technically not incorrect.

However, let's leverage the compiler's capabilities and require a
mutable reference to ensure exclusive access.

This also fixes a clippy warning introduced with 1.88:

  warning: mutable borrow from immutable input(s)
     --> rust/kernel/dma.rs:297:78
      |
  297 |     pub unsafe fn as_slice_mut(&self, offset: usize, count: usize) -> Result<&mut [T]> {
      |                                                                              ^^^^^^^^

Fixes: d37a39f6 ("rust: dma: add as_slice/write functions for CoherentAllocation")
Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Reviewed-by: default avatarAndreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: default avatarAbdiel Janulgue <abdiel.janulgue@gmail.com>
Reviewed-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Link: https://lore.kernel.org/r/20250628165120.90149-1-dakr@kernel.org


Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent c7e03c5c

rust/kernel/dma.rs

+2 −2
Original line number Diff line number Diff line
@@ -294,7 +294,7 @@ pub unsafe fn as_slice(&self, offset: usize, count: usize) -> Result<&[T]> { 
    ///   slice is live.

    /// * Callers must ensure that this call does not race with a read or write to the same region

    ///   while the returned slice is live.

    pub unsafe fn as_slice_mut(&self, offset: usize, count: usize) -> Result<&mut [T]> {

    pub unsafe fn as_slice_mut(&mut self, offset: usize, count: usize) -> Result<&mut [T]> {

        self.validate_range(offset, count)?;

        // SAFETY:

        // - The pointer is valid due to type invariant on `CoherentAllocation`,
@@ -326,7 +326,7 @@ pub unsafe fn as_slice_mut(&self, offset: usize, count: usize) -> Result<&mut [T 
    /// unsafe { alloc.write(buf, 0)?; }

    /// # Ok::<(), Error>(()) }

    /// ```

    pub unsafe fn write(&self, src: &[T], offset: usize) -> Result {

    pub unsafe fn write(&mut self, src: &[T], offset: usize) -> Result {

        self.validate_range(offset, src.len())?;

        // SAFETY:

        // - The pointer is valid due to type invariant on `CoherentAllocation`