[patch] sched: fix list traversal to use _rcu variant

["Chris Friesen" <cfriesen@nortel.com>]

From: Chris Friesen    <cfriesen@nortel.com>

load_balance_fair() calls rcu_read_lock() but then traverses the list
 using the regular list traversal routine.  This patch converts the
list traversal to use the _rcu version.

Signed-off-by: Chris Friesen <cfriesen@nortel.com>
Approval token "Nortel-02-July-2008-01"
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>

---

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index fb8994c..3c8f631 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1507,7 +1507,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 	rcu_read_lock();
 	update_h_load(busiest_cpu);
 
-	list_for_each_entry(tg, &task_groups, list) {
+	list_for_each_entry_rcu(tg, &task_groups, list) {
 		struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu];
 		unsigned long busiest_h_load = busiest_cfs_rq->h_load;
 		unsigned long busiest_weight = busiest_cfs_rq->load.weight;