ARM: perf: remove mysterious compiler barrier

There's a rather strange compiler barrier in the PMU disabling code
which was presumably placed there by aliens. There's no valid reason for
the barrier and one can only suspect that it's up to no good.

This patch removes it before it has a chance to spread.

Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index 1ac1531dcfef60f866926fe84b2be2d6211ecb62..22ed5120a6edc2090ac957a54437dbfa33a026c5 100644 (file)
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -223,7 +223,6 @@ armpmu_stop(struct perf_event *event, int flags)
         */
        if (!(hwc->state & PERF_HES_STOPPED)) {
                armpmu->disable(hwc, hwc->idx);
-               barrier(); /* why? */
                armpmu_event_update(event, hwc, hwc->idx);
                hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
        }