commit 0bbcc529fcea9c7de5e2e7243f9913b8f7302a8c
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> Mon May 16 02:24:04 2011 -0700
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> Thu May 26 09:42:20 2011 -0700
tree 22403b7c9bf3b87818c3a8a606a1bc33dd12bd1a
parent ba9f207c9f82115aba4ce04b22e0081af0ae300f

rcu: Add memory barriers

Add the memory barriers added by e59fb3120b.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcutree.c

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index e486f7c..3731141 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -907,6 +907,12 @@
 	unsigned long gp_duration;
 
 	WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
+
+	/*
+	 * Ensure that all grace-period and pre-grace-period activity
+	 * is seen before the assignment to rsp->completed.
+	 */
+	smp_mb(); /* See above block comment. */
 	gp_duration = jiffies - rsp->gp_start;
 	if (gp_duration > rsp->gp_max)
 		rsp->gp_max = gp_duration;