mm: add link from struct lruvec to struct zone

This is the first stage of struct mem_cgroup_zone removal.  Further
patches replace struct mem_cgroup_zone with a pointer to struct lruvec.

If CONFIG_CGROUP_MEM_RES_CTLR=n lruvec_zone() is just container_of().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8cbfc38..6092f33 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4358,7 +4358,6 @@
 	for (j = 0; j < MAX_NR_ZONES; j++) {
 		struct zone *zone = pgdat->node_zones + j;
 		unsigned long size, realsize, memmap_pages;
-		enum lru_list lru;
 
 		size = zone_spanned_pages_in_node(nid, j, zones_size);
 		realsize = size - zone_absent_pages_in_node(nid, j,
@@ -4408,12 +4407,7 @@
 		zone->zone_pgdat = pgdat;
 
 		zone_pcp_init(zone);
-		for_each_lru(lru)
-			INIT_LIST_HEAD(&zone->lruvec.lists[lru]);
-		zone->lruvec.reclaim_stat.recent_rotated[0] = 0;
-		zone->lruvec.reclaim_stat.recent_rotated[1] = 0;
-		zone->lruvec.reclaim_stat.recent_scanned[0] = 0;
-		zone->lruvec.reclaim_stat.recent_scanned[1] = 0;
+		lruvec_init(&zone->lruvec, zone);
 		zap_zone_vm_stats(zone);
 		zone->flags = 0;
 		if (!size)