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