Re: [PATCH v2 1/5] mm: Make per-VMA locks available universally

[Vlastimil Babka (SUSE)]

On 6/11/26 01:04, Dave Hansen wrote:

Not a Rust expert but...

> --- a/rust/kernel/mm.rs~unconditional-vma-locks	2026-06-10 15:57:54.051368539 -0700
> +++ b/rust/kernel/mm.rs	2026-06-10 15:57:54.078369499 -0700
> @@ -174,7 +174,6 @@ impl MmWithUser {
>      /// When per-vma locks are disabled, this always returns `None`.
>      #[inline]
>      pub fn lock_vma_under_rcu(&self, vma_addr: usize) -> Option<VmaReadGuard<'_>> {
> -        #[cfg(CONFIG_PER_VMA_LOCK)]
>          {
>              // SAFETY: Calling `bindings::lock_vma_under_rcu` is always okay given an mm where
>              // `mm_users` is non-zero.
> @@ -188,12 +187,6 @@ impl MmWithUser {
>                  });
>              }
>          }

Think you can remove the { } as well (as that was the scope of #[cfg] and
reduce indentation of what's inside.

> -
> -        // Silence warnings about unused variables.
> -        #[cfg(not(CONFIG_PER_VMA_LOCK))]
> -        let _ = vma_addr;
> -
> -        None

And here you should leave the 'None' as the #[cfg] only applied to the one
line below.

>      }
>  
>      /// Lock the mmap read lock.
> diff -puN tools/testing/vma/include/dup.h~unconditional-vma-locks tools/testing/vma/include/dup.h