Re: [PATCH v2 00/21] Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb())

[Linus Torvalds]

On Fri, Apr 5, 2019 at 6:09 AM Will Deacon <will.deacon@xxxxxxx> wrote:
> >
> > Or did I miss something? I think the ia64() mb/rmb/wmb stuff only
> > works on normal memory on ia64.
>
> I was worried about RISC-V, but actually their wmb() is "fence ow,ow"
> which I think is stronger than their mmiowb() "fence o,w" implementation.

Also with smp_store_release -> smp_load_acquire kind of ordering?

Again, this is not at all a NAK - I think we should do this - just
perhaps a request to add a note to the commit and make people aware of
the issue.

I suspect very few drivers use non-locking serialization to begin with.

                 Linus