From: Will Deacon <will.deacon@arm.com>
Date: Sat, 28 Jul 2012 15:44:38 +0000 (+0100)
Subject: ARM: perf: remove mysterious compiler barrier
X-Git-Tag: next-20120816~89^2~5
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=85ed81b3dac72b97331ee36402fee0318a93d4cb;p=karo-tx-linux.git

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 1ac1531dcfef..22ed5120a6ed 100644
--- 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;
 	}