1 files changed, 30 insertions, 0 deletions

diff --git a/mm/mmzone.c b/mm/mmzone.c
index eb5838634f18..486ed595ee6f 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -42,3 +42,33 @@ struct zone *next_zone(struct zone *zone)
         return zone;
 }
 
+static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes)
+{
+#ifdef CONFIG_NUMA
+        return node_isset(zonelist_node_idx(zref), *nodes);
+#else
+        return 1;
+#endif /* CONFIG_NUMA */
+}
+
+/* Returns the next zone at or below highest_zoneidx in a zonelist */
+struct zoneref *next_zones_zonelist(struct zoneref *z,
+                                        enum zone_type highest_zoneidx,
+                                        nodemask_t *nodes,
+                                        struct zone **zone)
+{
+        /*
+         * Find the next suitable zone to use for the allocation.
+         * Only filter based on nodemask if it's set
+         */
+        if (likely(nodes == NULL))
+                while (zonelist_zone_idx(z) > highest_zoneidx)
+                        z++;
+        else
+                while (zonelist_zone_idx(z) > highest_zoneidx ||
+                                (z->zone && !zref_in_nodemask(z, nodes)))
+                        z++;
+
+        *zone = zonelist_zone(z++);
+        return z;
+}