diff --git a/mm/mmzone.c b/mm/mmzone.c
new file mode 100644
index 0000000..b022370
--- /dev/null
+++ b/mm/mmzone.c
@@ -0,0 +1,50 @@
+/*
+ * linux/mm/mmzone.c
+ *
+ * management codes for pgdats and zones.
+ */
+
+
+#include <linux/config.h>
+#include <linux/stddef.h>
+#include <linux/mmzone.h>
+#include <linux/module.h>
+
+struct pglist_data *first_online_pgdat(void)
+{
+	return NODE_DATA(first_online_node);
+}
+
+EXPORT_SYMBOL(first_online_pgdat);
+
+struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
+{
+	int nid = next_online_node(pgdat->node_id);
+
+	if (nid == MAX_NUMNODES)
+		return NULL;
+	return NODE_DATA(nid);
+}
+EXPORT_SYMBOL(next_online_pgdat);
+
+
+/*
+ * next_zone - helper magic for for_each_zone()
+ */
+struct zone *next_zone(struct zone *zone)
+{
+	pg_data_t *pgdat = zone->zone_pgdat;
+
+	if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
+		zone++;
+	else {
+		pgdat = next_online_pgdat(pgdat);
+		if (pgdat)
+			zone = pgdat->node_zones;
+		else
+			zone = NULL;
+	}
+	return zone;
+}
+EXPORT_SYMBOL(next_zone);
+