linux-kernel - [PATCH] freezer: use smp barriers

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Message-Id: <1303716665-27584-1-git-send-email-vapier@gentoo.org>
Date:	Mon, 25 Apr 2011 03:31:05 -0400
From:	Mike Frysinger <vapier@...too.org>
To:	Pavel Machek <pavel@....cz>, "Rafael J. Wysocki" <rjw@...k.pl>
Cc:	linux-kernel@...r.kernel.org, linux-pm@...ts.linux-foundation.org
Subject: [PATCH] freezer: use smp barriers

The freezer processes are dealing with multiple threads running
simultaneously, and on a UP system, the memory reads/writes do
not need barriers to keep things in sync.  These are only needed
on SMP systems, so use SMP barriers instead.

Signed-off-by: Mike Frysinger <vapier@...too.org>
---
 kernel/freezer.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/freezer.c b/kernel/freezer.c
index 66ecd2e..7b01de9 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -17,7 +17,7 @@ static inline void frozen_process(void)
 {
 	if (!unlikely(current->flags & PF_NOFREEZE)) {
 		current->flags |= PF_FROZEN;
-		wmb();
+		smp_wmb();
 	}
 	clear_freeze_flag(current);
 }
@@ -93,7 +93,7 @@ bool freeze_task(struct task_struct *p, bool sig_only)
 	 * the task as frozen and next clears its TIF_FREEZE.
 	 */
 	if (!freezing(p)) {
-		rmb();
+		smp_rmb();
 		if (frozen(p))
 			return false;

-- 
1.7.5.rc1

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