Re: [PATCH v3 00/17] Cross-architecture definitions of relaxed MMIO accessors

From: Geert Uytterhoeven
Date: Thu Sep 25 2014 - 16:17:21 EST

Hi Arnd,

On Thu, Sep 25, 2014 at 9:17 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Thursday 25 September 2014, Daniel Thompson wrote:
>> > +
>> > +#ifndef readq_relaxed
>> > +#define readq_relaxed readq
>> > +#endif
>> Not really sure if it matters but this gives a rather surprising
>> behaviour to #ifdef readq_relaxed given that readq may not be defined.
> It was intentional. I could have written this as
> #if !defined(readq_relaxed) && defined(readq)
> but the effect would be almost the same, and the version I picked looks
> simpler.

However, as soon as a driver has code like

#ifdef readq_relaxed
do something using readq_relaxed

this will fail if readq is not defined.

Currently no code has such an #ifdef, though.
There are #ifdefs for checking for the presence of readq.

The same is true for writeq_relaxed.



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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