@@ -256,6 +256,13 @@ rust_helper_vrealloc(const void *p, size_t size, gfp_t flags)
}
EXPORT_SYMBOL_GPL(rust_helper_vrealloc);
+void * __must_check __realloc_size(2)
+rust_helper_kvrealloc(const void *p, size_t size, gfp_t flags)
+{
+ return kvrealloc(p, size, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kvrealloc);
+
void rust_helper_rb_link_node(struct rb_node *node, struct rb_node *parent,
struct rb_node **rb_link)
{
@@ -34,6 +34,15 @@
/// For more details see [self].
pub struct Vmalloc;
+/// The kvmalloc kernel allocator.
+///
+/// `KVmalloc` attempts to allocate memory with `Kmalloc` first, but falls back to `Vmalloc` upon
+/// failure. This allocator is typically used when the size for the requsted allocation is not
+/// known and may exceed the capabilities of `Kmalloc`.
+///
+/// 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.
@@ -76,6 +85,9 @@ impl ReallocFunc {
// INVARIANT: `vrealloc` satisfies the type invariants.
const VREALLOC: Self = Self(bindings::vrealloc);
+ // INVARIANT: `kvrealloc` satisfies the type invariants.
+ const KVREALLOC: Self = Self(bindings::kvrealloc);
+
/// # Safety
///
/// This method has the same safety requirements as [`Allocator::realloc`].
@@ -173,6 +185,25 @@ unsafe fn realloc(
}
}
+unsafe impl Allocator for KVmalloc {
+ #[inline]
+ unsafe fn realloc(
+ ptr: Option<NonNull<u8>>,
+ layout: Layout,
+ flags: Flags,
+ ) -> Result<NonNull<[u8]>, AllocError> {
+ // 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");
+ return Err(AllocError);
+ }
+
+ // SAFETY: If not `None`, `ptr` is guaranteed to point to valid memory, which was previously
+ // allocated with this `Allocator`.
+ unsafe { ReallocFunc::KVREALLOC.call(ptr, layout, flags) }
+ }
+}
+
#[global_allocator]
static ALLOCATOR: Kmalloc = Kmalloc;
@@ -8,6 +8,7 @@
pub struct Kmalloc;
pub type Vmalloc = Kmalloc;
+pub type KVmalloc = Kmalloc;
unsafe impl Allocator for Kmalloc {
unsafe fn realloc(