Re: [PATCH/RFC] m68k/bitops: Make bitmap data pointer of atomic ops volatile

[Geert Uytterhoeven <geert@linux-m68k.org>]

On Mon, Jun 6, 2011 at 22:11, Arnd Bergmann <arnd@arndb.de> wrote:
> On Monday 06 June 2011 22:07:53 Geert Uytterhoeven wrote:
>>
>> This fixes a.o.
>>
>> drivers/ide/ide-io.c: In function ‘ide_lock_host’:
>> drivers/ide/ide-io.c:415: warning: passing argument 2 of ‘__constant_test_and_set_bit’ discards qualifiers from pointer target type
>> drivers/ide/ide-io.c:415: warning: passing argument 2 of ‘__generic_test_and_set_bit’ discards qualifiers from pointer target type
>>
>> Suggested-by: Ben Hutchings <ben@decadent.org.uk>
>> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
> I think the correct fix would be to mark the variable not volatile, as it
> clearly has no business be marked as such. That doesn't mean your patch

You mean the host_busy variable in the IDE code?
That would also apply to context_flag in the DRM code:

drivers/gpu/drm/drm_context.c:233: warning: passing argument 2 of
‘__constant_test_and_set_bit’ discards qualifiers from pointer target
type
drivers/gpu/drm/drm_context.c:233: warning: passing argument 2 of
‘__generic_test_and_set_bit’ discards qualifiers from pointer target
type

> is wrong, though. It probably doesn't hurt to do both.

asm-generic/bitops/atomic.h has the volatiles everywhere. That's why
I'm wondering.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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