From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

jiffies subtraction may cause an overflow problem.  It should be using
time_after().

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/page_alloc.c~zlc_setup-handle-jiffies-wraparound mm/page_alloc.c
--- a/mm/page_alloc.c~zlc_setup-handle-jiffies-wraparound
+++ a/mm/page_alloc.c
@@ -1276,7 +1276,7 @@ static nodemask_t *zlc_setup(struct zone
 	if (!zlc)
 		return NULL;
 
-	if (jiffies - zlc->last_full_zap > 1 * HZ) {
+       if (time_after(jiffies, zlc->last_full_zap + HZ)) {
 		bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
 		zlc->last_full_zap = jiffies;
 	}
_