Re: [RFC v2 3/4] Documentation/locking/atomic: Add a litmus test for atomic_set()

[Alan Stern]

On Wed, 19 Feb 2020, Boqun Feng wrote:

> We already use a litmus test in atomic_t.txt to describe the behavior of
> an atomic_set() with the an atomic RMW, so add it into atomic-tests
> directory to make it easily accessible for anyone who cares about the
> semantics of our atomic APIs.
> 
> Additionally, change the sentences describing the test in atomic_t.txt
> with better wording.

One very minor point about the new working in atomic_t.txt:

> diff --git a/Documentation/atomic_t.txt b/Documentation/atomic_t.txt
> index ceb85ada378e..d30cb3d87375 100644
> --- a/Documentation/atomic_t.txt
> +++ b/Documentation/atomic_t.txt
> @@ -85,10 +85,10 @@ smp_store_release() respectively. Therefore, if you find yourself only using
>  the Non-RMW operations of atomic_t, you do not in fact need atomic_t at all
>  and are doing it wrong.
>  
> -A subtle detail of atomic_set{}() is that it should be observable to the RMW
> -ops. That is:
> +A note for the implementation of atomic_set{}() is that it cannot break the
> +atomicity of the RMW ops. That is:

This would be slightly better if you changed it to: "it must not break".

The comments in the litmus test and README file are okay as they stand.

Alan