rust: alloc: fix rusttest by providing Cmalloc::aligned_layout too

[ Upstream commit 0f580d5d3d ]

Commit fde578c862 ("rust: alloc: replace aligned_size() with
Kmalloc::aligned_layout()") provides a public `aligned_layout` function
in `Kamlloc`, but not in `Cmalloc`, and thus uses of it will trigger an
error in `rusttest`.

Such a user appeared in the following commit 22ab0641b9 ("rust: drm:
ensure kmalloc() compatible Layout"):

    error[E0599]: no function or associated item named `aligned_layout` found for struct `alloc::allocator_test::Cmalloc` in the current scope
       --> rust/kernel/drm/device.rs💯31
        |
    100 |         let layout = Kmalloc::aligned_layout(Layout:🆕:<Self>());
        |                               ^^^^^^^^^^^^^^ function or associated item not found in `Cmalloc`
        |
       ::: rust/kernel/alloc/allocator_test.rs:19:1
        |
    19  | pub struct Cmalloc;
        | ------------------ function or associated item `aligned_layout` not found for this struct

Thus add an equivalent one for `Cmalloc`.

Fixes: fde578c862 ("rust: alloc: replace aligned_size() with Kmalloc::aligned_layout()")
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250816204215.2719559-1-ojeda@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Miguel Ojeda 2025-08-16 22:42:15 +02:00 committed by Greg Kroah-Hartman
parent bce19c62ed
commit a0d2e6f9d3

View File

@ -22,6 +22,17 @@ pub type Kmalloc = Cmalloc;
pub type Vmalloc = Kmalloc;
pub type KVmalloc = Kmalloc;
impl Cmalloc {
/// 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()
}
}
extern "C" {
#[link_name = "aligned_alloc"]
fn libc_aligned_alloc(align: usize, size: usize) -> *mut crate::ffi::c_void;