Re: [PATCH v2 16/18] x86: io: implement dummy relaxed accessor macros for writes

[H. Peter Anvin]

On 05/22/2014 09:47 AM, Will Deacon wrote:
> write{b,w,l,q}_relaxed are implemented by some architectures in order to
> permit memory-mapped I/O accesses with weaker barrier semantics than the
> non-relaxed variants.
> 
> This patch adds dummy macros for the read and write accessors to x86,
> which simply expand to the non-relaxed variants. Note that this
> strengthens the relaxed read accessors, since they are now ordered with
> respect to each other by way of a compiler barrier.

OK, do we want/need that compiler barrier?  And you say "strengthens" -
strengthens with respect to what if we didn't have them before?

	-hpa

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/