diff options
| -rw-r--r-- | rust/kernel/alloc/allocator.rs | 19 |
1 files 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 @@ use core::ptr; 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 @@ struct KernelAllocator; /// - `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 |