diff --git a/drivers/md/dm-region-hash.c b/drivers/md/dm-region-hash.c
index 168bd38..bd5c58b 100644
--- a/drivers/md/dm-region-hash.c
+++ b/drivers/md/dm-region-hash.c
@@ -11,6 +11,7 @@
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/vmalloc.h>
 
 #include "dm.h"