26 #define tty_ldisc_debug(tty, f, args...)	tty_debug(tty, f, ##args)  argument
28 #define tty_ldisc_debug(tty, f, args...)  argument
166 static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)  in tty_ldisc_get()  argument
194 	ld->tty = tty;  in tty_ldisc_get()
268 struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)  in tty_ldisc_ref_wait()  argument
272 	ldsem_down_read(&tty->ldisc_sem, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_ref_wait()
273 	ld = tty->ldisc;  in tty_ldisc_ref_wait()
275 		ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref_wait()
289 struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)  in tty_ldisc_ref()  argument
293 	if (ldsem_down_read_trylock(&tty->ldisc_sem)) {  in tty_ldisc_ref()
294 		ld = tty->ldisc;  in tty_ldisc_ref()
296 			ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref()
312 	ldsem_up_read(&ld->tty->ldisc_sem);  in tty_ldisc_deref()
318 __tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock()  argument
320 	return ldsem_down_write(&tty->ldisc_sem, timeout);  in __tty_ldisc_lock()
324 __tty_ldisc_lock_nested(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock_nested()  argument
326 	return ldsem_down_write_nested(&tty->ldisc_sem,  in __tty_ldisc_lock_nested()
330 static inline void __tty_ldisc_unlock(struct tty_struct *tty)  in __tty_ldisc_unlock()  argument
332 	ldsem_up_write(&tty->ldisc_sem);  in __tty_ldisc_unlock()
335 int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in tty_ldisc_lock()  argument
340 	set_bit(TTY_LDISC_CHANGING, &tty->flags);  in tty_ldisc_lock()
341 	wake_up_interruptible_all(&tty->read_wait);  in tty_ldisc_lock()
342 	wake_up_interruptible_all(&tty->write_wait);  in tty_ldisc_lock()
344 	ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock()
347 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock()
351 void tty_ldisc_unlock(struct tty_struct *tty)  in tty_ldisc_unlock()  argument
353 	clear_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_unlock()
355 	clear_bit(TTY_LDISC_CHANGING, &tty->flags);  in tty_ldisc_unlock()
356 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock()
360 tty_ldisc_lock_pair_timeout(struct tty_struct *tty, struct tty_struct *tty2,  in tty_ldisc_lock_pair_timeout()  argument
365 	if (tty < tty2) {  in tty_ldisc_lock_pair_timeout()
366 		ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
370 				__tty_ldisc_unlock(tty);  in tty_ldisc_lock_pair_timeout()
374 		WARN_ON_ONCE(tty == tty2);  in tty_ldisc_lock_pair_timeout()
375 		if (tty2 && tty != tty2) {  in tty_ldisc_lock_pair_timeout()
378 				ret = __tty_ldisc_lock_nested(tty, timeout);  in tty_ldisc_lock_pair_timeout()
383 			ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
389 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock_pair_timeout()
395 static void tty_ldisc_lock_pair(struct tty_struct *tty, struct tty_struct *tty2)  in tty_ldisc_lock_pair()  argument
397 	tty_ldisc_lock_pair_timeout(tty, tty2, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_lock_pair()
400 static void tty_ldisc_unlock_pair(struct tty_struct *tty,  in tty_ldisc_unlock_pair()  argument
403 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock_pair()
416 void tty_ldisc_flush(struct tty_struct *tty)  in tty_ldisc_flush()  argument
418 	struct tty_ldisc *ld = tty_ldisc_ref(tty);  in tty_ldisc_flush()
420 	tty_buffer_flush(tty, ld);  in tty_ldisc_flush()
442 static void tty_set_termios_ldisc(struct tty_struct *tty, int disc)  in tty_set_termios_ldisc()  argument
444 	down_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
445 	tty->termios.c_line = disc;  in tty_set_termios_ldisc()
446 	up_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
448 	tty->disc_data = NULL;  in tty_set_termios_ldisc()
449 	tty->receive_room = 0;  in tty_set_termios_ldisc()
463 static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_open()  argument
465 	WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_open()
469 		ret = ld->ops->open(tty);  in tty_ldisc_open()
471 			clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_open()
473 		tty_ldisc_debug(tty, "%p: opened\n", ld);  in tty_ldisc_open()
488 static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_close()  argument
490 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_close()
491 	WARN_ON(!test_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_close()
492 	clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_close()
494 		ld->ops->close(tty);  in tty_ldisc_close()
495 	tty_ldisc_debug(tty, "%p: closed\n", ld);  in tty_ldisc_close()
507 static int tty_ldisc_failto(struct tty_struct *tty, int ld)  in tty_ldisc_failto()  argument
509 	struct tty_ldisc *disc = tty_ldisc_get(tty, ld);  in tty_ldisc_failto()
512 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_failto()
515 	tty->ldisc = disc;  in tty_ldisc_failto()
516 	tty_set_termios_ldisc(tty, ld);  in tty_ldisc_failto()
517 	if ((r = tty_ldisc_open(tty, disc)) < 0)  in tty_ldisc_failto()
531 static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)  in tty_ldisc_restore()  argument
534 	if (tty_ldisc_failto(tty, old->ops->num) < 0) {  in tty_ldisc_restore()
535 		const char *name = tty_name(tty);  in tty_ldisc_restore()
541 		if (tty_ldisc_failto(tty, N_TTY) < 0 &&  in tty_ldisc_restore()
542 		    tty_ldisc_failto(tty, N_NULL) < 0)  in tty_ldisc_restore()
558 int tty_set_ldisc(struct tty_struct *tty, int disc)  in tty_set_ldisc()  argument
563 	new_ldisc = tty_ldisc_get(tty, disc);  in tty_set_ldisc()
567 	tty_lock(tty);  in tty_set_ldisc()
568 	retval = tty_ldisc_lock(tty, 5 * HZ);  in tty_set_ldisc()
572 	if (!tty->ldisc) {  in tty_set_ldisc()
578 	if (tty->ldisc->ops->num == disc)  in tty_set_ldisc()
581 	if (test_bit(TTY_HUPPED, &tty->flags)) {  in tty_set_ldisc()
587 	old_ldisc = tty->ldisc;  in tty_set_ldisc()
590 	tty_ldisc_close(tty, old_ldisc);  in tty_set_ldisc()
593 	tty->ldisc = new_ldisc;  in tty_set_ldisc()
594 	tty_set_termios_ldisc(tty, disc);  in tty_set_ldisc()
596 	retval = tty_ldisc_open(tty, new_ldisc);  in tty_set_ldisc()
600 		tty_ldisc_restore(tty, old_ldisc);  in tty_set_ldisc()
603 	if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) {  in tty_set_ldisc()
604 		down_read(&tty->termios_rwsem);  in tty_set_ldisc()
605 		tty->ops->set_ldisc(tty);  in tty_set_ldisc()
606 		up_read(&tty->termios_rwsem);  in tty_set_ldisc()
616 	tty_ldisc_unlock(tty);  in tty_set_ldisc()
620 	tty_buffer_restart_work(tty->port);  in tty_set_ldisc()
623 	tty_unlock(tty);  in tty_set_ldisc()
634 static void tty_ldisc_kill(struct tty_struct *tty)  in tty_ldisc_kill()  argument
636 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_kill()
637 	if (!tty->ldisc)  in tty_ldisc_kill()
642 	tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_kill()
643 	tty_ldisc_put(tty->ldisc);  in tty_ldisc_kill()
645 	tty->ldisc = NULL;  in tty_ldisc_kill()
655 static void tty_reset_termios(struct tty_struct *tty)  in tty_reset_termios()  argument
657 	down_write(&tty->termios_rwsem);  in tty_reset_termios()
658 	tty->termios = tty->driver->init_termios;  in tty_reset_termios()
659 	tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);  in tty_reset_termios()
660 	tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);  in tty_reset_termios()
661 	up_write(&tty->termios_rwsem);  in tty_reset_termios()
679 int tty_ldisc_reinit(struct tty_struct *tty, int disc)  in tty_ldisc_reinit()  argument
684 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_reinit()
685 	ld = tty_ldisc_get(tty, disc);  in tty_ldisc_reinit()
691 	if (tty->ldisc) {  in tty_ldisc_reinit()
692 		tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_reinit()
693 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
697 	tty->ldisc = ld;  in tty_ldisc_reinit()
698 	tty_set_termios_ldisc(tty, disc);  in tty_ldisc_reinit()
699 	retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_reinit()
701 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
702 		tty->ldisc = NULL;  in tty_ldisc_reinit()
722 void tty_ldisc_hangup(struct tty_struct *tty, bool reinit)  in tty_ldisc_hangup()  argument
726 	tty_ldisc_debug(tty, "%p: hangup\n", tty->ldisc);  in tty_ldisc_hangup()
728 	ld = tty_ldisc_ref(tty);  in tty_ldisc_hangup()
731 			ld->ops->flush_buffer(tty);  in tty_ldisc_hangup()
732 		tty_driver_flush_buffer(tty);  in tty_ldisc_hangup()
733 		if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&  in tty_ldisc_hangup()
735 			ld->ops->write_wakeup(tty);  in tty_ldisc_hangup()
737 			ld->ops->hangup(tty);  in tty_ldisc_hangup()
741 	wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);  in tty_ldisc_hangup()
742 	wake_up_interruptible_poll(&tty->read_wait, EPOLLIN);  in tty_ldisc_hangup()
750 	tty_ldisc_lock(tty, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_hangup()
752 	if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)  in tty_ldisc_hangup()
753 		tty_reset_termios(tty);  in tty_ldisc_hangup()
755 	if (tty->ldisc) {  in tty_ldisc_hangup()
757 			if (tty_ldisc_reinit(tty, tty->termios.c_line) < 0 &&  in tty_ldisc_hangup()
758 			    tty_ldisc_reinit(tty, N_TTY) < 0)  in tty_ldisc_hangup()
759 				WARN_ON(tty_ldisc_reinit(tty, N_NULL) < 0);  in tty_ldisc_hangup()
761 			tty_ldisc_kill(tty);  in tty_ldisc_hangup()
763 	tty_ldisc_unlock(tty);  in tty_ldisc_hangup()
776 int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)  in tty_ldisc_setup()  argument
778 	int retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_setup()
789 			tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_setup()
804 void tty_ldisc_release(struct tty_struct *tty)  in tty_ldisc_release()  argument
806 	struct tty_struct *o_tty = tty->link;  in tty_ldisc_release()
813 	tty_ldisc_lock_pair(tty, o_tty);  in tty_ldisc_release()
814 	tty_ldisc_kill(tty);  in tty_ldisc_release()
817 	tty_ldisc_unlock_pair(tty, o_tty);  in tty_ldisc_release()
822 	tty_ldisc_debug(tty, "released\n");  in tty_ldisc_release()
834 int tty_ldisc_init(struct tty_struct *tty)  in tty_ldisc_init()  argument
836 	struct tty_ldisc *ld = tty_ldisc_get(tty, N_TTY);  in tty_ldisc_init()
839 	tty->ldisc = ld;  in tty_ldisc_init()
850 void tty_ldisc_deinit(struct tty_struct *tty)  in tty_ldisc_deinit()  argument
853 	if (tty->ldisc)  in tty_ldisc_deinit()
854 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_deinit()
855 	tty->ldisc = NULL;  in tty_ldisc_deinit()