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authorJakub Kicinski <kuba@kernel.org>2025-06-12 10:08:24 -0700
committerJakub Kicinski <kuba@kernel.org>2025-08-29 11:48:01 -0700
commitd23ad54de795ec0054f90ecb03b41e8f2c410f3a (patch)
tree93ee9c1bfac4b54c567cc613039d4898cac04871 /rust/kernel/alloc/allocator.rs
parent29828b81a46a3ae55ebc053fce512219172560ba (diff)
parent9c736ace0666efe68efd53fcdfa2c6653c3e0e72 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.17-rc4). No conflicts. Adjacent changes: drivers/net/ethernet/intel/idpf/idpf_txrx.c 02614eee26fb ("idpf: do not linearize big TSO packets") 6c4e68480238 ("idpf: remove obsolete stashing code") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'rust/kernel/alloc/allocator.rs')
-rw-r--r--rust/kernel/alloc/allocator.rs30
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");