From b49967b57fbaa67b1fe64ae0ee227069b642f880 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Thu, 13 Sep 2012 11:01:00 +1000
Subject: [PATCH] 
 mm-compaction-abort-compaction-loop-if-lock-is-contended-or-run-too-long-fix

make compact_zone_order() require non-NULL arg `contended'

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shaohua Li <shli@fusionio.com>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/compaction.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 6a6bb4b3b18d..36ff6079ba1e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -909,8 +909,7 @@ static unsigned long compact_zone_order(struct zone *zone,
 	INIT_LIST_HEAD(&cc.migratepages);
 
 	ret = compact_zone(zone, &cc);
-	if (contended)
-		*contended = cc.contended;
+	*contended = cc.contended;
 	return ret;
 }
 
-- 
2.39.5