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authorDanilo Krummrich <dakr@kernel.org>2024-10-04 17:41:06 +0200
committerMiguel Ojeda <ojeda@kernel.org>2024-10-14 17:55:40 +0200
commita654a6e09644266e38ac05415ef7737d299c4497 (patch)
tree04051b67c0c165c7199fabeef27368b305da5ed6 /rust
parentb7a084ba4fbb8f416ce8d19c93a3a2bee63c9c89 (diff)
rust: alloc: separate `aligned_size` from `krealloc_aligned`
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>
Diffstat (limited to 'rust')
-rw-r--r--rust/kernel/alloc/allocator.rs19
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