setup_per_zone_pages_min(): take zone->lock instead of zone->lru_lock

This replaces zone->lru_lock in setup_per_zone_pages_min() with zone->lock.
There seems to be no need for the lru_lock anymore, but there is a need for
zone->lock instead, because that function may call move_freepages() via
setup_zone_migrate_reserve().

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -4242,7 +4242,7 @@ void setup_per_zone_pages_min(void)
 	for_each_zone(zone) {
 		u64 tmp;
 
-		spin_lock_irqsave(&zone->lru_lock, flags);
+		spin_lock_irqsave(&zone->lock, flags);
 		tmp = (u64)pages_min * zone->present_pages;
 		do_div(tmp, lowmem_pages);
 		if (is_highmem(zone)) {
@@ -4274,7 +4274,7 @@ void setup_per_zone_pages_min(void)
 		zone->pages_low   = zone->pages_min + (tmp >> 2);
 		zone->pages_high  = zone->pages_min + (tmp >> 1);
 		setup_zone_migrate_reserve(zone);
-		spin_unlock_irqrestore(&zone->lru_lock, flags);
+		spin_unlock_irqrestore(&zone->lock, flags);
 	}
 
 	/* update totalreserve_pages */