Commit f7afdc47 authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

rust: dma: make use of start_ptr() and start_ptr_mut() 



Using start_ptr() and start_ptr_mut() has the advantage that we inherit
the requirements the a mutable or immutable reference from those
methods.

Hence, use them instead of self.cpu_addr.

Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20251103190655.2326191-1-dakr@kernel.org


[ Keep using self.cpu_addr in item_from_index(). - Danilo ]
Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent d8407396

rust/kernel/dma.rs

+8 −4
Original line number Diff line number Diff line
@@ -505,7 +505,7 @@ pub unsafe fn as_slice(&self, offset: usize, count: usize) -> Result<&[T]> { 
        //   data is also guaranteed by the safety requirements of the function.

        // - `offset + count` can't overflow since it is smaller than `self.count` and we've checked

        //   that `self.count` won't overflow early in the constructor.

        Ok(unsafe { core::slice::from_raw_parts(self.cpu_addr.add(offset), count) })

        Ok(unsafe { core::slice::from_raw_parts(self.start_ptr().add(offset), count) })

    }



    /// Performs the same functionality as [`CoherentAllocation::as_slice`], except that a mutable
@@ -525,7 +525,7 @@ pub unsafe fn as_slice_mut(&mut self, offset: usize, count: usize) -> Result<&mu 
        //   data is also guaranteed by the safety requirements of the function.

        // - `offset + count` can't overflow since it is smaller than `self.count` and we've checked

        //   that `self.count` won't overflow early in the constructor.

        Ok(unsafe { core::slice::from_raw_parts_mut(self.cpu_addr.add(offset), count) })

        Ok(unsafe { core::slice::from_raw_parts_mut(self.start_ptr_mut().add(offset), count) })

    }



    /// Writes data to the region starting from `offset`. `offset` is in units of `T`, not the
@@ -557,7 +557,11 @@ pub unsafe fn write(&mut self, src: &[T], offset: usize) -> Result { 
        // - `offset + count` can't overflow since it is smaller than `self.count` and we've checked

        //   that `self.count` won't overflow early in the constructor.

        unsafe {

            core::ptr::copy_nonoverlapping(src.as_ptr(), self.cpu_addr.add(offset), src.len())

            core::ptr::copy_nonoverlapping(

                src.as_ptr(),

                self.start_ptr_mut().add(offset),

                src.len(),

            )

        };

        Ok(())

    }
@@ -637,7 +641,7 @@ fn drop(&mut self) { 
            bindings::dma_free_attrs(

                self.dev.as_raw(),

                size,

                self.cpu_addr.cast(),

                self.start_ptr_mut().cast(),

                self.dma_handle,

                self.dma_attrs.as_raw(),

            )