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

[Geert Uytterhoeven]

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
#else
...
#endif

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.

Gr{oetje,eeting}s,

                        Geert

--
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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/