From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Mon, 6 Mar 2006 23:42:51 +0000 (-0800)
Subject: [PATCH] time: add barrier after updating jiffies_64
X-Git-Tag: v2.6.16-rc6~96
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5aee405c662ca644980c184774277fc6d0769a84;p=linux-2.6

[PATCH] time: add barrier after updating jiffies_64

Add a compiler barrier so that we don't read jiffies before updating
jiffies_64.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/kernel/timer.c b/kernel/timer.c
index 8256f3f5ec..bf7c4193b9 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -941,6 +941,8 @@ static inline void update_times(void)
 void do_timer(struct pt_regs *regs)
 {
 	jiffies_64++;
+	/* prevent loading jiffies before storing new jiffies_64 value. */
+	barrier();
 	update_times();
 	softlockup_tick(regs);
 }