mm: vmscan: reclaim highmem zone if buffer_heads is over limit

commit 7bf52fb891b64b8d61caf0b82060adb9db761aec upstream.

We have been reclaimed highmem zone if buffer_heads is over limit but
commit 6b4f7799c6a5 ("mm: vmscan: invoke slab shrinkers from
shrink_zone()") changed the behavior so it doesn't reclaim highmem zone
although buffer_heads is over the limit.  This patch restores the logic.

Fixes: 6b4f7799c6a5 ("mm: vmscan: invoke slab shrinkers from shrink_zone()")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2aec424..0c114e2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2534,7 +2534,7 @@
 		sc->gfp_mask |= __GFP_HIGHMEM;
 
 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
-					requested_highidx, sc->nodemask) {
+					gfp_zone(sc->gfp_mask), sc->nodemask) {
 		enum zone_type classzone_idx;
 
 		if (!populated_zone(zone))