From e81db568e650a7d99b6fdb8b1739fa1db774fac1 Mon Sep 17 00:00:00 2001
From: Darren Hart <dvhltc@us.ibm.com>
Date: Thu, 24 Sep 2009 11:54:47 -0700
Subject: [PATCH] --- yaml --- r: 166450 b: refs/heads/master c:
 9beba3c54dd180a26a1da2027cfbe9edfaf9c40e h: refs/heads/master v: v3

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

diff --git a/[refs] b/[refs]
index 7bfb67043bed..eda5b970f7e4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0729e196147692d84d4c099fcff056eba2ed61d8
+refs/heads/master: 9beba3c54dd180a26a1da2027cfbe9edfaf9c40e
diff --git a/trunk/kernel/futex.c b/trunk/kernel/futex.c
index 463af2efa512..b911adceb2c4 100644
--- a/trunk/kernel/futex.c
+++ b/trunk/kernel/futex.c
@@ -1656,6 +1656,12 @@ static int fixup_owner(u32 __user *uaddr, int fshared, struct futex_q *q,
 static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q,
 				struct hrtimer_sleeper *timeout)
 {
+	/*
+	 * The task state is guaranteed to be set before another task can
+	 * wake it. set_current_state() is implemented using set_mb() and
+	 * queue_me() calls spin_unlock() upon completion, both serializing
+	 * access to the hash list and forcing another memory barrier.
+	 */
 	set_current_state(TASK_INTERRUPTIBLE);
 	queue_me(q, hb);