cdev_kqfilter
error = cdev_kqfilter(dev, kn);
return cdev_kqfilter(vp->v_rdev, ap->a_kn);
error = cdev_kqfilter(devctty, ap->a_kn);
error = cdev_kqfilter(dev, ap->a_kn);
dev_type_kqfilter(cdev_kqfilter);