diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 78c48ab..71231a5 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1688,6 +1688,7 @@
 extern int bdev_write_page(struct block_device *, sector_t, struct page *,
 						struct writeback_control *);
 extern long bdev_direct_access(struct block_device *, struct blk_dax_ctl *);
+extern int bdev_dax_supported(struct super_block *, int);
 #else /* CONFIG_BLOCK */
 
 struct block_device;