diff --git a/module/zfs/include/sys/vdev_disk.h b/module/zfs/include/sys/vdev_disk.h
index 3d5ec0eb89..520db0103d 100644
--- a/module/zfs/include/sys/vdev_disk.h
+++ b/module/zfs/include/sys/vdev_disk.h
@@ -18,8 +18,8 @@ typedef struct vdev_disk {
 } vdev_disk_t;
 
 extern int vdev_disk_physio(ldi_handle_t, caddr_t, size_t, uint64_t, int);
-
-#endif
+extern int vdev_disk_read_rootlabel(char *, char *, nvlist_t **);
+#endif /* _KERNEL */
 
 #ifdef	__cplusplus
 }