Commit-ID: da706d8bc833e7153622435560422e653bdb2e94 Gitweb: http://git.kernel.org/tip/da706d8bc833e7153622435560422e653bdb2e94 Author: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> AuthorDate: Wed, 15 Jul 2009 16:27:30 +0800 Committer: Frederic Weisbecker <fweisbec@xxxxxxxxx> CommitDate: Thu, 16 Jul 2009 18:46:47 -0400 ring_buffer: Fix warning while ignoring cmpxchg return value 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, because we don't need here to handle the fail case of cmpxchg, it's fine if an interrupt already did the job. Changed from V1: Add a comment(which is written by Steven) for it. Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> --- kernel/trace/ring_buffer.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-) 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. -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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