Re: About commit "io: change inX() to have their own IO barrier overrides"

[John Garry]

+ linux-arch

For background, see 
https://lore.kernel.org/lkml/2e80d7bc-32a0-cc40-00a9-8a383a1966c2@xxxxxxxxxx/

> > So today only ARM64 uses it for this relevant code, above. But maybe
> > others in future will want to use it - any arch without native IO port
> > access is a candidate.
>
> I'm looking at Arnd here for help.
>
> > > As long as the expectations are set, I see no reason why it shouldn't
> > > but, I'll let Arnd comment on it too.
> >
> > ok, so it looks reasonable consider replicating your change for ***, above.

To be clear, I would make this change in lib/logic_pio.c since 
__io_pbr() can be overridden per-arch:

 #define BUILD_LOGIC_IO(bw, type)
 type logic_in##bw(unsigned long addr)
 {
      type ret = (type)~0;
      if (addr < MMIO_UPPER_LIMIT) {
-          ret = read##bw(PCI_IOBASE + addr);
+          __io_pbr();
+          ret = __raw_read##bw(PCI_IOBASE + addr);
+          __io_pbr();	
      } else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) {
          struct logic_pio_hwaddr *entry = find_io_range(addr);

...

(forgetting leX_to_cpu for the moment)

> Arnd is the maintainer here. We should consult first.

ok, fine.

> I believe there is also a linux-arch mailing list. Going there with this
> question makes sense IMO.

Cheers,
John