diff --git a/include/linux/idr.h b/include/linux/idr.h
index 9a2d762124de..1af61d23be36 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -15,6 +15,7 @@
 #include <linux/types.h>
 #include <linux/bitops.h>
 #include <linux/init.h>
+#include <linux/rcupdate.h>
 
 #if BITS_PER_LONG == 32
 # define IDR_BITS 5
@@ -51,6 +52,7 @@ struct idr_layer {
 	unsigned long		 bitmap; /* A zero bit means "space here" */
 	struct idr_layer	*ary[1<<IDR_BITS];
 	int			 count;	 /* When zero, we can release it */
+	struct rcu_head		 rcu_head;
 };
 
 struct idr {