Messages in this thread |  | | | Date | Tue, 14 Jul 2009 18:43:40 -0400 (EDT) | | From | Steven Rostedt <> | | Subject | Re: [PATCH -tip] ring_buffer: fix warning |
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On Tue, 14 Jul 2009, Frederic Weisbecker wrote:
> On Tue, Jul 14, 2009 at 03:35:37PM +0800, Lai Jiangshan wrote: > > > > 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 a "(void)" to fix this warning. > > > > Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> > > --- > > diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c > > index e648ba4..d371279 100644 > > --- a/kernel/trace/ring_buffer.c > > +++ b/kernel/trace/ring_buffer.c > > @@ -846,8 +846,8 @@ static int rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer, > > * not come in and change it. In which case, we > > * do not want to modify it. > > */ > > - 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. > > > Looks good. Indeed the rest of the path remains the same, whether the > interrupts have already won the race or not.
Yes, but it needs a comment:
/* * 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. */ Then you can have my:
Acked-by: Steven Rostedt <rostedt@goodmis.org>
-- Steve
> > Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> > >
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