diff --git a/sys/compat/linux/linux_ioctl.c b/sys/compat/linux/linux_ioctl.c
index 82675f364a26..f19a2da1728c 100644
--- a/sys/compat/linux/linux_ioctl.c
+++ b/sys/compat/linux/linux_ioctl.c
@@ -118,6 +118,7 @@ linux_ioctl_disk(struct thread *td, struct linux_ioctl_args *args)
 		return (error);
 	switch (args->cmd & 0xffff) {
 	case LINUX_BLKGETSIZE:
+		/* XXX: wrong, should use DIOCGMEDIASIZE/DIOCGSECTORSIZE */
 		error = fo_ioctl(fp, DIOCGDINFO, (caddr_t)&dl, td->td_ucred,
 		    td);
 		fdrop(fp, td);