diff options
| author | Joonas Lahtinen <joonas.lahtinen@linux.intel.com> | 2025-09-16 13:53:20 +0300 |
|---|---|---|
| committer | Joonas Lahtinen <joonas.lahtinen@linux.intel.com> | 2025-09-16 13:53:20 +0300 |
| commit | f088104d837a991c65e51fa30bb4196169b3244d (patch) | |
| tree | ae53729f52e5c1938f34373cfef77c740defab89 /rust/kernel/alloc/allocator.rs | |
| parent | f4d4097a036ab1ec6bc8154160c49ab9a0a92895 (diff) | |
| parent | 5770495279d79514989b00fe9ef0ff487bf2e54e (diff) | |
Merge drm/drm-next into drm-intel-gt-next
Backmerge in order to get the commit:
048832a3f400 ("drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter")
To drm-intel-gt-next as there are followup fixes to be applied.
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Diffstat (limited to 'rust/kernel/alloc/allocator.rs')
| -rw-r--r-- | rust/kernel/alloc/allocator.rs | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs index aa2dfa9dca4c..2692cf90c948 100644 --- a/rust/kernel/alloc/allocator.rs +++ b/rust/kernel/alloc/allocator.rs @@ -43,17 +43,6 @@ pub struct Vmalloc; /// For more details see [self]. pub struct KVmalloc; -/// Returns a proper size to alloc a new object aligned to `new_layout`'s alignment. -fn aligned_size(new_layout: Layout) -> usize { - // Customized layouts from `Layout::from_size_align()` can have size < align, so pad first. - let layout = new_layout.pad_to_align(); - - // Note that `layout.size()` (after padding) is guaranteed to be a multiple of `layout.align()` - // which together with the slab guarantees means the `krealloc` will return a properly aligned - // object (see comments in `kmalloc()` for more information). - layout.size() -} - /// # Invariants /// /// One of the following: `krealloc`, `vrealloc`, `kvrealloc`. @@ -88,7 +77,7 @@ impl ReallocFunc { old_layout: Layout, flags: Flags, ) -> Result<NonNull<[u8]>, AllocError> { - let size = aligned_size(layout); + let size = layout.size(); let ptr = match ptr { Some(ptr) => { if old_layout.size() == 0 { @@ -123,6 +112,17 @@ impl ReallocFunc { } } +impl Kmalloc { + /// Returns a [`Layout`] that makes [`Kmalloc`] fulfill the requested size and alignment of + /// `layout`. + pub fn aligned_layout(layout: Layout) -> Layout { + // Note that `layout.size()` (after padding) is guaranteed to be a multiple of + // `layout.align()` which together with the slab guarantees means that `Kmalloc` will return + // a properly aligned object (see comments in `kmalloc()` for more information). + layout.pad_to_align() + } +} + // SAFETY: `realloc` delegates to `ReallocFunc::call`, which guarantees that // - memory remains valid until it is explicitly freed, // - passing a pointer to a valid memory allocation is OK, @@ -135,6 +135,8 @@ unsafe impl Allocator for Kmalloc { old_layout: Layout, flags: Flags, ) -> Result<NonNull<[u8]>, AllocError> { + let layout = Kmalloc::aligned_layout(layout); + // SAFETY: `ReallocFunc::call` has the same safety requirements as `Allocator::realloc`. unsafe { ReallocFunc::KREALLOC.call(ptr, layout, old_layout, flags) } } @@ -176,6 +178,10 @@ unsafe impl Allocator for KVmalloc { old_layout: Layout, flags: Flags, ) -> Result<NonNull<[u8]>, AllocError> { + // `KVmalloc` may use the `Kmalloc` backend, hence we have to enforce a `Kmalloc` + // compatible layout. + let layout = Kmalloc::aligned_layout(layout); + // TODO: Support alignments larger than PAGE_SIZE. if layout.align() > bindings::PAGE_SIZE { pr_warn!("KVmalloc does not support alignments larger than PAGE_SIZE yet.\n"); |
