Re: [PATCH] x86: cmpxchg_double: Add missing memory clobber

[Pranith Kumar]

On Tue, Oct 6, 2015 at 4:16 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>
> NAK.  We already have the "+m" for exactly this reason; adding an
> explicit memory clobber should only be used to prevent movement of
> *other* memory operations around this one (i.e. a barrier).
>

OK. If that is so, can you please explain why we need it in the
__raw_cmpxchg() case? I think it is a good idea to make cmpxchg() and
cmpxchg_double() have similar barrier semantics.

Thanks!
-- 
Pranith
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