On Mon, Jun 13, 2016 at 04:17:19PM +0200, Andrew Jones wrote:
> On Mon, Jun 13, 2016 at 04:03:53PM +0200, Paolo Bonzini wrote:
> > Are the barriers really necessary? I.e. why do we need
> > __raw_{read,write}* vs just {read,write}*.
>
> We could drop the wrappers, and require unit tests to use barriers
> explicitly, when needed. I'm OK with that, because I think I mostly
> forget that we have them in the wrappers and use them explicitly
> anyway... I'll need to double check all the uses though.
According to my findings read*/write* io accessors are used on
ioremap-ed areas in lib/arm/io.c and lib/virtio-mmio.c at the moment.
Even if read*/write* wrappers are stripped of SMP barriers,
removing compiler barriers from them would be a bad idea AFAICT.
So if we need compiler barriers in read*/write* then why not
just leave SMP barriers there?
> Thanks,
> drew
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