26 #define tty_ldisc_debug(tty, f, args...)	tty_debug(tty, f, ##args)  argument
28 #define tty_ldisc_debug(tty, f, args...)  argument
159 static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)  in tty_ldisc_get()  argument
185 	ld->tty = tty;  in tty_ldisc_get()
259 struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)  in tty_ldisc_ref_wait()  argument
263 	ldsem_down_read(&tty->ldisc_sem, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_ref_wait()
264 	ld = tty->ldisc;  in tty_ldisc_ref_wait()
266 		ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref_wait()
280 struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)  in tty_ldisc_ref()  argument
284 	if (ldsem_down_read_trylock(&tty->ldisc_sem)) {  in tty_ldisc_ref()
285 		ld = tty->ldisc;  in tty_ldisc_ref()
287 			ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref()
303 	ldsem_up_read(&ld->tty->ldisc_sem);  in tty_ldisc_deref()
309 __tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock()  argument
311 	return ldsem_down_write(&tty->ldisc_sem, timeout);  in __tty_ldisc_lock()
315 __tty_ldisc_lock_nested(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock_nested()  argument
317 	return ldsem_down_write_nested(&tty->ldisc_sem,  in __tty_ldisc_lock_nested()
321 static inline void __tty_ldisc_unlock(struct tty_struct *tty)  in __tty_ldisc_unlock()  argument
323 	ldsem_up_write(&tty->ldisc_sem);  in __tty_ldisc_unlock()
326 int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in tty_ldisc_lock()  argument
330 	ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock()
333 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock()
337 void tty_ldisc_unlock(struct tty_struct *tty)  in tty_ldisc_unlock()  argument
339 	clear_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_unlock()
340 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock()
344 tty_ldisc_lock_pair_timeout(struct tty_struct *tty, struct tty_struct *tty2,  in tty_ldisc_lock_pair_timeout()  argument
349 	if (tty < tty2) {  in tty_ldisc_lock_pair_timeout()
350 		ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
354 				__tty_ldisc_unlock(tty);  in tty_ldisc_lock_pair_timeout()
358 		WARN_ON_ONCE(tty == tty2);  in tty_ldisc_lock_pair_timeout()
359 		if (tty2 && tty != tty2) {  in tty_ldisc_lock_pair_timeout()
362 				ret = __tty_ldisc_lock_nested(tty, timeout);  in tty_ldisc_lock_pair_timeout()
367 			ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
373 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock_pair_timeout()
379 static void tty_ldisc_lock_pair(struct tty_struct *tty, struct tty_struct *tty2)  in tty_ldisc_lock_pair()  argument
381 	tty_ldisc_lock_pair_timeout(tty, tty2, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_lock_pair()
384 static void tty_ldisc_unlock_pair(struct tty_struct *tty,  in tty_ldisc_unlock_pair()  argument
387 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock_pair()
400 void tty_ldisc_flush(struct tty_struct *tty)  in tty_ldisc_flush()  argument
402 	struct tty_ldisc *ld = tty_ldisc_ref(tty);  in tty_ldisc_flush()
404 	tty_buffer_flush(tty, ld);  in tty_ldisc_flush()
426 static void tty_set_termios_ldisc(struct tty_struct *tty, int disc)  in tty_set_termios_ldisc()  argument
428 	down_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
429 	tty->termios.c_line = disc;  in tty_set_termios_ldisc()
430 	up_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
432 	tty->disc_data = NULL;  in tty_set_termios_ldisc()
433 	tty->receive_room = 0;  in tty_set_termios_ldisc()
447 static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_open()  argument
449 	WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_open()
453 		ret = ld->ops->open(tty);  in tty_ldisc_open()
455 			clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_open()
457 		tty_ldisc_debug(tty, "%p: opened\n", ld);  in tty_ldisc_open()
472 static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_close()  argument
474 	WARN_ON(!test_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_close()
475 	clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_close()
477 		ld->ops->close(tty);  in tty_ldisc_close()
478 	tty_ldisc_debug(tty, "%p: closed\n", ld);  in tty_ldisc_close()
490 static int tty_ldisc_failto(struct tty_struct *tty, int ld)  in tty_ldisc_failto()  argument
492 	struct tty_ldisc *disc = tty_ldisc_get(tty, ld);  in tty_ldisc_failto()
497 	tty->ldisc = disc;  in tty_ldisc_failto()
498 	tty_set_termios_ldisc(tty, ld);  in tty_ldisc_failto()
499 	if ((r = tty_ldisc_open(tty, disc)) < 0)  in tty_ldisc_failto()
513 static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)  in tty_ldisc_restore()  argument
516 	if (tty_ldisc_failto(tty, old->ops->num) < 0) {  in tty_ldisc_restore()
517 		const char *name = tty_name(tty);  in tty_ldisc_restore()
523 		if (tty_ldisc_failto(tty, N_TTY) < 0 &&  in tty_ldisc_restore()
524 		    tty_ldisc_failto(tty, N_NULL) < 0)  in tty_ldisc_restore()
540 int tty_set_ldisc(struct tty_struct *tty, int disc)  in tty_set_ldisc()  argument
545 	new_ldisc = tty_ldisc_get(tty, disc);  in tty_set_ldisc()
549 	tty_lock(tty);  in tty_set_ldisc()
550 	retval = tty_ldisc_lock(tty, 5 * HZ);  in tty_set_ldisc()
554 	if (!tty->ldisc) {  in tty_set_ldisc()
560 	if (tty->ldisc->ops->num == disc)  in tty_set_ldisc()
563 	if (test_bit(TTY_HUPPED, &tty->flags)) {  in tty_set_ldisc()
569 	old_ldisc = tty->ldisc;  in tty_set_ldisc()
572 	tty_ldisc_close(tty, old_ldisc);  in tty_set_ldisc()
575 	tty->ldisc = new_ldisc;  in tty_set_ldisc()
576 	tty_set_termios_ldisc(tty, disc);  in tty_set_ldisc()
578 	retval = tty_ldisc_open(tty, new_ldisc);  in tty_set_ldisc()
582 		tty_ldisc_restore(tty, old_ldisc);  in tty_set_ldisc()
585 	if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) {  in tty_set_ldisc()
586 		down_read(&tty->termios_rwsem);  in tty_set_ldisc()
587 		tty->ops->set_ldisc(tty);  in tty_set_ldisc()
588 		up_read(&tty->termios_rwsem);  in tty_set_ldisc()
598 	tty_ldisc_unlock(tty);  in tty_set_ldisc()
602 	tty_buffer_restart_work(tty->port);  in tty_set_ldisc()
605 	tty_unlock(tty);  in tty_set_ldisc()
616 static void tty_ldisc_kill(struct tty_struct *tty)  in tty_ldisc_kill()  argument
618 	if (!tty->ldisc)  in tty_ldisc_kill()
623 	tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_kill()
624 	tty_ldisc_put(tty->ldisc);  in tty_ldisc_kill()
626 	tty->ldisc = NULL;  in tty_ldisc_kill()
636 static void tty_reset_termios(struct tty_struct *tty)  in tty_reset_termios()  argument
638 	down_write(&tty->termios_rwsem);  in tty_reset_termios()
639 	tty->termios = tty->driver->init_termios;  in tty_reset_termios()
640 	tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);  in tty_reset_termios()
641 	tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);  in tty_reset_termios()
642 	up_write(&tty->termios_rwsem);  in tty_reset_termios()
660 int tty_ldisc_reinit(struct tty_struct *tty, int disc)  in tty_ldisc_reinit()  argument
665 	ld = tty_ldisc_get(tty, disc);  in tty_ldisc_reinit()
671 	if (tty->ldisc) {  in tty_ldisc_reinit()
672 		tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_reinit()
673 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
677 	tty->ldisc = ld;  in tty_ldisc_reinit()
678 	tty_set_termios_ldisc(tty, disc);  in tty_ldisc_reinit()
679 	retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_reinit()
681 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
682 		tty->ldisc = NULL;  in tty_ldisc_reinit()
702 void tty_ldisc_hangup(struct tty_struct *tty, bool reinit)  in tty_ldisc_hangup()  argument
706 	tty_ldisc_debug(tty, "%p: hangup\n", tty->ldisc);  in tty_ldisc_hangup()
708 	ld = tty_ldisc_ref(tty);  in tty_ldisc_hangup()
711 			ld->ops->flush_buffer(tty);  in tty_ldisc_hangup()
712 		tty_driver_flush_buffer(tty);  in tty_ldisc_hangup()
713 		if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&  in tty_ldisc_hangup()
715 			ld->ops->write_wakeup(tty);  in tty_ldisc_hangup()
717 			ld->ops->hangup(tty);  in tty_ldisc_hangup()
721 	wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);  in tty_ldisc_hangup()
722 	wake_up_interruptible_poll(&tty->read_wait, EPOLLIN);  in tty_ldisc_hangup()
730 	tty_ldisc_lock(tty, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_hangup()
732 	if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)  in tty_ldisc_hangup()
733 		tty_reset_termios(tty);  in tty_ldisc_hangup()
735 	if (tty->ldisc) {  in tty_ldisc_hangup()
737 			if (tty_ldisc_reinit(tty, tty->termios.c_line) < 0 &&  in tty_ldisc_hangup()
738 			    tty_ldisc_reinit(tty, N_TTY) < 0)  in tty_ldisc_hangup()
739 				WARN_ON(tty_ldisc_reinit(tty, N_NULL) < 0);  in tty_ldisc_hangup()
741 			tty_ldisc_kill(tty);  in tty_ldisc_hangup()
743 	tty_ldisc_unlock(tty);  in tty_ldisc_hangup()
756 int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)  in tty_ldisc_setup()  argument
758 	int retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_setup()
765 			tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_setup()
780 void tty_ldisc_release(struct tty_struct *tty)  in tty_ldisc_release()  argument
782 	struct tty_struct *o_tty = tty->link;  in tty_ldisc_release()
789 	tty_ldisc_lock_pair(tty, o_tty);  in tty_ldisc_release()
790 	tty_ldisc_kill(tty);  in tty_ldisc_release()
793 	tty_ldisc_unlock_pair(tty, o_tty);  in tty_ldisc_release()
798 	tty_ldisc_debug(tty, "released\n");  in tty_ldisc_release()
810 int tty_ldisc_init(struct tty_struct *tty)  in tty_ldisc_init()  argument
812 	struct tty_ldisc *ld = tty_ldisc_get(tty, N_TTY);  in tty_ldisc_init()
815 	tty->ldisc = ld;  in tty_ldisc_init()
826 void tty_ldisc_deinit(struct tty_struct *tty)  in tty_ldisc_deinit()  argument
828 	if (tty->ldisc)  in tty_ldisc_deinit()
829 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_deinit()
830 	tty->ldisc = NULL;  in tty_ldisc_deinit()