diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 48ec886..2bad616 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1074,6 +1074,8 @@
 	struct module *owner;
 };
 
+extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
+				 unsigned long);
 #else /* CONFIG_BLOCK */
 /*
  * stubs for when the block layer is configured out