[PATCH] mm: simplify build_zonelists_node by removing the case statement.

Simplify build_zonelists_node by removing the case statement.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 23 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8f3de5af92dd..7adc9526d329 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1455,35 +1455,23 @@ 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;
-                if (zone->present_pages) {
+static int __init build_zonelists_node(pg_data_t *pgdat,
+                        struct zonelist *zonelist, int j, int k)
+{
+        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 (zone->present_pages)
-                        zonelist->zones[j++] = zone;
-        case ZONE_DMA32:
-                zone = pgdat->node_zones + ZONE_DMA32;
-                if (zone->present_pages)
-                        zonelist->zones[j++] = zone;
-        case ZONE_DMA:
-                zone = pgdat->node_zones + ZONE_DMA;
-                if (zone->present_pages)
-                        zonelist->zones[j++] = zone;
         }
-
         return j;
 }