[PATCH] wait_table and zonelist initializing for memory hotadd: add return code for init_current_empty_zone

When add_zone() is called against empty zone (not populated zone), we have to
initialize the zone which didn't initialize at boot time.  But,
init_currently_empty_zone() may fail due to allocation of wait table.  So,
this patch is to catch its error code.

Changes against wait_table is in the next patch.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5ae75be..4bc66f6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2050,8 +2050,9 @@
 			zone->name, zone->present_pages, batch);
 }
 
-static __meminit void init_currently_empty_zone(struct zone *zone,
-		unsigned long zone_start_pfn, unsigned long size)
+__meminit int init_currently_empty_zone(struct zone *zone,
+					unsigned long zone_start_pfn,
+					unsigned long size)
 {
 	struct pglist_data *pgdat = zone->zone_pgdat;
 
@@ -2063,6 +2064,8 @@
 	memmap_init(size, pgdat->node_id, zone_idx(zone), zone_start_pfn);
 
 	zone_init_free_lists(pgdat, zone, zone->spanned_pages);
+
+	return 0;
 }
 
 /*
@@ -2077,6 +2080,7 @@
 	unsigned long j;
 	int nid = pgdat->node_id;
 	unsigned long zone_start_pfn = pgdat->node_start_pfn;
+	int ret;
 
 	pgdat_resize_init(pgdat);
 	pgdat->nr_zones = 0;
@@ -2118,7 +2122,8 @@
 			continue;
 
 		zonetable_add(zone, nid, j, zone_start_pfn, size);
-		init_currently_empty_zone(zone, zone_start_pfn, size);
+		ret = init_currently_empty_zone(zone, zone_start_pfn, size);
+		BUG_ON(ret);
 		zone_start_pfn += size;
 	}
 }