static void free_tty_struct(struct tty_struct *tty)
{
	tty_ldisc_deinit(tty);
	put_device(tty->dev);
	kfree(tty->write_buf);
	tty->magic = 0xDEADDEAD;
	kfree(tty);
}
static void free_tty_struct(struct tty_struct *tty)
{
	tty_ldisc_deinit(tty);
	put_device(tty->dev);
	kfree(tty->write_buf);
	tty->magic = 0xDEADDEAD;
	kfree(tty);
}