Re: [PATCH v7] alpha: fix memory barriers so that they conform to the specification

["Maciej W. Rozycki" <macro@xxxxxxx>]

On Tue, 26 May 2020, Mikulas Patocka wrote:

> This patch makes barriers confiorm to the specification.
> 
> 1. We add mb() before readX_relaxed and writeX_relaxed -
>    memory-barriers.txt claims that these functions must be ordered w.r.t.
>    each other. Alpha doesn't order them, so we need an explicit barrier.
> 2. We add mb() before reads from the I/O space - so that if there's a
>    write followed by a read, there should be a barrier between them.
> 
> Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> Fixes: cd0e00c10672 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering")
> Fixes: 92d7223a7423 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2")
> Cc: stable@xxxxxxxxxxxxxxx      # v4.17+
> Acked-by: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>

 LGTM, thanks for persistence!

Reviewed-by: Maciej W. Rozycki <macro@xxxxxxxxxxxxxx>

  Maciej