[PATCH] Fix zone policy determination

The use k in the inner loop means that the highest zone nr is always used
if any zone of a node is populated.  This means that the policy zone is not
correctly determined on arches that do no use HIGHMEM like ia64.

Change the loop to decrement k which also simplifies the BUG_ON.

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, 7 insertions, 3 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 512e3f4d4963..ca978992c898 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1465,15 +1465,19 @@ static int __init build_zonelists_node(pg_data_t *pgdat,
         struct zone *zone;
 
         BUG_ON(k > ZONE_HIGHMEM);
-        for (zone = pgdat->node_zones + k; zone >= pgdat->node_zones; zone--) {
+
+        do {
+                zone = pgdat->node_zones + k;
                 if (populated_zone(zone)) {
 #ifndef CONFIG_HIGHMEM
-                        BUG_ON(zone - pgdat->node_zones > ZONE_NORMAL);
+                        BUG_ON(k > ZONE_NORMAL);
 #endif
                         zonelist->zones[j++] = zone;
                         check_highest_zone(k);
                 }
-        }
+                k--;
+
+        } while (k >= 0);
         return j;
 }