diff --git a/sys/sys/disk.h b/sys/sys/disk.h
index 958714b199d9..78ceb65948b9 100644
--- a/sys/sys/disk.h
+++ b/sys/sys/disk.h
@@ -31,6 +31,7 @@ struct disk {
 	struct diskslices	*d_slice;
 	struct disklabel	d_label;
 	LIST_ENTRY(disk)	d_list;
+	void			*d_softc;
 };
 
 #define DISKFLAG_LOCK		0x1