Re: [PATCH] rust: atomic: add fetch_sub

[Alice Ryhl <aliceryhl@google.com>]

On Wed, Jan 28, 2026 at 01:47:11PM +0100, Andreas Hindborg wrote:
> Add `Atomic::fetch_sub` with implementation and documentation in line with
> existing `Atomic::fetch_add` implementation.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>

> +    /// let x = Atomic::new(42);
> +    ///
> +    /// assert_eq!(42, x.load(Relaxed));
> +    ///
> +    /// assert_eq!(30, { x.fetch_sub(12, Acquire); x.load(Relaxed) });

These asserts are a bit confusing to read. After all, the fetch_sub call
also returns a value, so how about this?

let x = Atomic::new(42);
assert_eq!(42, x.load(Relaxed));
assert_eq!(42, x.fetch_sub(12, Acquire));
assert_eq!(30, x.load(Relaxed));

Otherwise LGTM.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>

Alice