Simplify build_zonelists_node by removing the case statement.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.15-rc5-mm1/mm/page_alloc.c
===================================================================
--- linux-2.6.15-rc5-mm1.orig/mm/page_alloc.c	2005-12-06 17:22:51.000000000 -0800
+++ linux-2.6.15-rc5-mm1/mm/page_alloc.c	2005-12-06 19:22:26.000000000 -0800
@@ -1567,35 +1567,21 @@ void show_free_areas(void)
 
 /*
  * Builds allocation fallback zone lists.
+ *
+ * Add all populated zones of a node to the zonelist.
  */
 static int __init build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist, int j, int k)
 {
-	switch (k) {
-		struct zone *zone;
-	default:
-		BUG();
-	case ZONE_HIGHMEM:
-		zone = pgdat->node_zones + ZONE_HIGHMEM;
+	struct zone *zone;
+
+	BUG_ON(k > ZONE_HIGHMEM);
+	for (zone = pgdat->node_zones + k; zone >= pgdat->node_zones; zone--)
 		if (populated_zone(zone)) {
 #ifndef CONFIG_HIGHMEM
-			BUG();
+			BUG_ON(zone - pgdat->node_zones > ZONE_NORMAL);
 #endif
 			zonelist->zones[j++] = zone;
 		}
-	case ZONE_NORMAL:
-		zone = pgdat->node_zones + ZONE_NORMAL;
-		if (populated_zone(zone))
-			zonelist->zones[j++] = zone;
-	case ZONE_DMA32:
-		zone = pgdat->node_zones + ZONE_DMA32;
-		if (populated_zone(zone))
-			zonelist->zones[j++] = zone;
-	case ZONE_DMA:
-		zone = pgdat->node_zones + ZONE_DMA;
-		if (populated_zone(zone))
-			zonelist->zones[j++] = zone;
-	}
-
 	return j;
 }