From: Danilo Krummrich dakr@kernel.org
commit a654a6e09644266e38ac05415ef7737d299c4497 upstream.
Separate `aligned_size` from `krealloc_aligned`.
Subsequent patches implement `Allocator` derivates, such as `Kmalloc`, that require `aligned_size` and replace the original `krealloc_aligned`.
Reviewed-by: Alice Ryhl aliceryhl@google.com Reviewed-by: Benno Lossin benno.lossin@proton.me Reviewed-by: Gary Guo gary@garyguo.net Signed-off-by: Danilo Krummrich dakr@kernel.org Link: https://lore.kernel.org/r/20241004154149.93856-3-dakr@kernel.org Signed-off-by: Miguel Ojeda ojeda@kernel.org --- rust/kernel/alloc/allocator.rs | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs index 91216b36af69..765f72d5bc21 100644 --- a/rust/kernel/alloc/allocator.rs +++ b/rust/kernel/alloc/allocator.rs @@ -8,6 +8,17 @@
struct KernelAllocator;
+/// 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() +} + /// Calls `krealloc` with a proper size to alloc a new object aligned to `new_layout`'s alignment. /// /// # Safety @@ -15,13 +26,7 @@ /// - `ptr` can be either null or a pointer which has been allocated by this allocator. /// - `new_layout` must have a non-zero size. pub(crate) unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: Flags) -> *mut u8 { - // 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). - let size = layout.size(); + let size = aligned_size(new_layout);
// SAFETY: // - `ptr` is either null or a pointer returned from a previous `k{re}alloc()` by the