Re: [PATCH 2/3] rust: allocator: Use krealloc_aligned() in KernelAllocator::alloc

[Andreas Hindborg (Samsung)]

Boqun Feng <boqun.feng@xxxxxxxxx> writes:

> This fixes the potential issue that when KernelAllocator is used, the
> allocation may be mis-aligned due to SLAB's alignment guarantee.
>
> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> ---
>  rust/kernel/allocator.rs | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
> index fae11d1fdba7..1aec688cf0e0 100644
> --- a/rust/kernel/allocator.rs
> +++ b/rust/kernel/allocator.rs
> @@ -41,9 +41,9 @@ unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: bindings::gf
>  
>  unsafe impl GlobalAlloc for KernelAllocator {
>      unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
> -        // `krealloc()` is used instead of `kmalloc()` because the latter is
> -        // an inline function and cannot be bound to as a result.
> -        unsafe { bindings::krealloc(ptr::null(), layout.size(), bindings::GFP_KERNEL) as *mut u8 }
> +        // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
> +        // requirement.
> +        unsafe { krealloc_aligned(ptr::null_mut(), layout, bindings::GFP_KERNEL) }
>      }
>  
>      unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {

Reviewed-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>