diff --git a/include/linux/memory.h b/include/linux/memory.h
index 0def328..9a42438 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -54,6 +54,9 @@
  */
 #define	MEM_MAPPING_INVALID	(1<<3)
 
+struct notifier_block;
+struct mem_section;
+
 #ifndef CONFIG_MEMORY_HOTPLUG
 static inline int memory_dev_init(void)
 {