diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index c357f27..b8144b2 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -136,6 +136,7 @@
 struct backing_dev_info {
 	struct list_head bdi_list;
 	unsigned long ra_pages;	/* max readahead in PAGE_SIZE units */
+	unsigned long io_pages;	/* max allowed IO size */
 	unsigned int capabilities; /* Device capabilities */
 	congested_fn *congested_fn; /* Function pointer if device is md/dm */
 	void *congested_data;	/* Pointer to aux data for congested func */