perf/x86: Fix cmpxchg() usage in amd_put_event_constraints()

Now the return value of cmpxchg() is used to match an event. The
change removes the duplicate event comparison and traverses the list
until an event was removed. This also fixes the following warning:

 arch/x86/kernel/cpu/perf_event_amd.c:170: warning: value computed is not used

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1333643084-26776-3-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Robert Richter 2012-04-05 18:24:42 +02:00 committed by Ingo Molnar
parent 10c250234c
commit 5f09fc6889

View file

@ -205,10 +205,8 @@ static void amd_put_event_constraints(struct cpu_hw_events *cpuc,
* when we come here
*/
for (i = 0; i < x86_pmu.num_counters; i++) {
if (nb->owners[i] == event) {
cmpxchg(nb->owners+i, event, NULL);
if (cmpxchg(nb->owners + i, event, NULL) == event)
break;
}
}
}