From 313509f13bc801da6527a4236237b079a90fe4a5 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Mon, 16 May 2011 02:24:04 -0700
Subject: [PATCH] --- yaml --- r: 252671 b: refs/heads/master c:
 0bbcc529fcea9c7de5e2e7243f9913b8f7302a8c h: refs/heads/master i:   252669:
 ffebfb55f1ae5c12101b9b836a87d803a03b5bac   252667:
 cdd4b70bd9471cca8c73e2214587e836dc0df1c4   252663:
 02226666a5e28e359e5ca66228e9a6454dcebe3e   252655:
 e206ae2ad5844ceda77ac6ebd02c87ea12a45efc   252639:
 95e11540066033677d1bdcee2b24b11607e6b0a2   252607:
 d231989b021ce5f615fb76ebc0826ba8917ca0dc   252543:
 767469c6577fbb77c3012f6e5c233c3085c2db72   252415:
 e5875fedb346d082f3b83c05ffb4745810dcb7f0 v: v3

---
 [refs]                 | 2 +-
 trunk/kernel/rcutree.c | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 5a9e6b4c341d..c718ba2cb76c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ba9f207c9f82115aba4ce04b22e0081af0ae300f
+refs/heads/master: 0bbcc529fcea9c7de5e2e7243f9913b8f7302a8c
diff --git a/trunk/kernel/rcutree.c b/trunk/kernel/rcutree.c
index e486f7c3ffb8..3731141d8ad7 100644
--- a/trunk/kernel/rcutree.c
+++ b/trunk/kernel/rcutree.c
@@ -907,6 +907,12 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags)
 	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;