Messages in this thread | | | Date | Thu, 16 Jul 2009 12:10:57 -0400 | From | Frederic Weisbecker <> | Subject | Re: [PATCH -tip V2] ring_buffer: fix warning |
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On Wed, Jul 15, 2009 at 04:27:30PM +0800, Lai Jiangshan wrote: > Sorry for missing Reviewed-by and Acked-by, so I resend it. > > Subject: [PATCH -tip V2] ring_buffer: fix warning > > kernel/trace/ring_buffer.c: In function 'rb_tail_page_update': > kernel/trace/ring_buffer.c:849: warning: value computed is not used > kernel/trace/ring_buffer.c:850: warning: value computed is not used > > Add "(void)"s to fix this warning. > > Changed from V1: > Add a comment(which is written by Steven) for it. > > Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> > Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> > Acked-by: Steven Rostedt <rostedt@goodmis.org>
Queued for .32, thanks!
> --- > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > index e648ba4..51633d7 100644 > --- a/kernel/trace/ring_buffer.c > +++ b/kernel/trace/ring_buffer.c > @@ -845,9 +845,14 @@ static int rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer, > * This will only succeed if an interrupt did > * not come in and change it. In which case, we > * do not want to modify it. > + * > + * We add (void) to let the compiler know that we do not care > + * about the return value of these functions. We use the > + * cmpxchg to only update if an interrupt did not already > + * do it for us. If the cmpxchg fails, we don't care. > */ > - local_cmpxchg(&next_page->write, old_write, val); > - local_cmpxchg(&next_page->entries, old_entries, eval); > + (void)local_cmpxchg(&next_page->write, old_write, val); > + (void)local_cmpxchg(&next_page->entries, old_entries, eval); > > /* > * No need to worry about races with clearing out the commit. >
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