cdev_write
error = cdev_write(dev, uio, flag);
error = cdev_write(vp->v_rdev, ap->a_uio, ap->a_ioflag);
error = cdev_write(devctty, ap->a_uio, ap->a_ioflag);
error = cdev_write(dev, uio, ap->a_ioflag);
dev_type_write(cdev_write);