diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 07a7a41..e7baabf 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -386,7 +386,15 @@
 	/* per cpu variables */
 	struct raid5_percpu {
 		struct page	*spare_page; /* Used when checking P/Q in raid6 */
+		void		*scribble;   /* space for constructing buffer
+					      * lists and performing address
+					      * conversions
+					      */
 	} *percpu;
+	size_t			scribble_len; /* size of scribble region must be
+					       * associated with conf to handle
+					       * cpu hotplug while reshaping
+					       */
 #ifdef CONFIG_HOTPLUG_CPU
 	struct notifier_block	cpu_notify;
 #endif