Re: [PATCH] rust: atomic: add fetch_sub

[Andreas Hindborg <a.hindborg@kernel.org>]

"Alice Ryhl" <aliceryhl@google.com> writes:

> 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));

We can do that. I basically copied the docs from add. Should I change
those as well?


Best regards,
Andreas Hindborg