diff --git a/include/linux/raid/linear.h b/include/linux/raid/linear.h
index 7eaf290..ba15469 100644
--- a/include/linux/raid/linear.h
+++ b/include/linux/raid/linear.h
@@ -13,8 +13,10 @@
 
 struct linear_private_data
 {
+	struct linear_private_data *prev;	/* earlier version */
 	dev_info_t		**hash_table;
 	sector_t		hash_spacing;
+	sector_t		array_size;
 	int			preshift; /* shift before dividing by hash_spacing */
 	dev_info_t		disks[0];
 };