diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 61103d2..e3d1c33 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -171,6 +171,7 @@
 /*
  * Info functions.
  */
+const char *dm_device_name(struct mapped_device *md);
 struct gendisk *dm_disk(struct mapped_device *md);
 int dm_suspended(struct mapped_device *md);