27 #define tty_ldisc_debug(tty, f, args...)	tty_debug(tty, f, ##args)  argument
29 #define tty_ldisc_debug(tty, f, args...)  argument
139 static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)  in tty_ldisc_get()  argument
167 	ld->tty = tty;  in tty_ldisc_get()
239 struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)  in tty_ldisc_ref_wait()  argument
243 	ldsem_down_read(&tty->ldisc_sem, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_ref_wait()
244 	ld = tty->ldisc;  in tty_ldisc_ref_wait()
246 		ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref_wait()
259 struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)  in tty_ldisc_ref()  argument
263 	if (ldsem_down_read_trylock(&tty->ldisc_sem)) {  in tty_ldisc_ref()
264 		ld = tty->ldisc;  in tty_ldisc_ref()
266 			ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref()
281 	ldsem_up_read(&ld->tty->ldisc_sem);  in tty_ldisc_deref()
287 __tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock()  argument
289 	return ldsem_down_write(&tty->ldisc_sem, timeout);  in __tty_ldisc_lock()
293 __tty_ldisc_lock_nested(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock_nested()  argument
295 	return ldsem_down_write_nested(&tty->ldisc_sem,  in __tty_ldisc_lock_nested()
299 static inline void __tty_ldisc_unlock(struct tty_struct *tty)  in __tty_ldisc_unlock()  argument
301 	ldsem_up_write(&tty->ldisc_sem);  in __tty_ldisc_unlock()
304 int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in tty_ldisc_lock()  argument
309 	set_bit(TTY_LDISC_CHANGING, &tty->flags);  in tty_ldisc_lock()
310 	wake_up_interruptible_all(&tty->read_wait);  in tty_ldisc_lock()
311 	wake_up_interruptible_all(&tty->write_wait);  in tty_ldisc_lock()
313 	ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock()
316 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock()
320 void tty_ldisc_unlock(struct tty_struct *tty)  in tty_ldisc_unlock()  argument
322 	clear_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_unlock()
324 	clear_bit(TTY_LDISC_CHANGING, &tty->flags);  in tty_ldisc_unlock()
325 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock()
329 tty_ldisc_lock_pair_timeout(struct tty_struct *tty, struct tty_struct *tty2,  in tty_ldisc_lock_pair_timeout()  argument
334 	if (tty < tty2) {  in tty_ldisc_lock_pair_timeout()
335 		ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
339 				__tty_ldisc_unlock(tty);  in tty_ldisc_lock_pair_timeout()
343 		WARN_ON_ONCE(tty == tty2);  in tty_ldisc_lock_pair_timeout()
344 		if (tty2 && tty != tty2) {  in tty_ldisc_lock_pair_timeout()
347 				ret = __tty_ldisc_lock_nested(tty, timeout);  in tty_ldisc_lock_pair_timeout()
352 			ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
358 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock_pair_timeout()
364 static void tty_ldisc_lock_pair(struct tty_struct *tty, struct tty_struct *tty2)  in tty_ldisc_lock_pair()  argument
366 	tty_ldisc_lock_pair_timeout(tty, tty2, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_lock_pair()
369 static void tty_ldisc_unlock_pair(struct tty_struct *tty,  in tty_ldisc_unlock_pair()  argument
372 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock_pair()
384 void tty_ldisc_flush(struct tty_struct *tty)  in tty_ldisc_flush()  argument
386 	struct tty_ldisc *ld = tty_ldisc_ref(tty);  in tty_ldisc_flush()
388 	tty_buffer_flush(tty, ld);  in tty_ldisc_flush()
407 static void tty_set_termios_ldisc(struct tty_struct *tty, int disc)  in tty_set_termios_ldisc()  argument
409 	down_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
410 	tty->termios.c_line = disc;  in tty_set_termios_ldisc()
411 	up_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
413 	tty->disc_data = NULL;  in tty_set_termios_ldisc()
414 	tty->receive_room = 0;  in tty_set_termios_ldisc()
426 static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_open()  argument
428 	WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_open()
432 		ret = ld->ops->open(tty);  in tty_ldisc_open()
434 			clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_open()
436 		tty_ldisc_debug(tty, "%p: opened\n", ld);  in tty_ldisc_open()
449 static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_close()  argument
451 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_close()
452 	WARN_ON(!test_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_close()
453 	clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_close()
455 		ld->ops->close(tty);  in tty_ldisc_close()
456 	tty_ldisc_debug(tty, "%p: closed\n", ld);  in tty_ldisc_close()
467 static int tty_ldisc_failto(struct tty_struct *tty, int ld)  in tty_ldisc_failto()  argument
469 	struct tty_ldisc *disc = tty_ldisc_get(tty, ld);  in tty_ldisc_failto()
472 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_failto()
475 	tty->ldisc = disc;  in tty_ldisc_failto()
476 	tty_set_termios_ldisc(tty, ld);  in tty_ldisc_failto()
477 	r = tty_ldisc_open(tty, disc);  in tty_ldisc_failto()
491 static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)  in tty_ldisc_restore()  argument
494 	if (tty_ldisc_failto(tty, old->ops->num) < 0) {  in tty_ldisc_restore()
495 		const char *name = tty_name(tty);  in tty_ldisc_restore()
503 		if (tty_ldisc_failto(tty, N_TTY) < 0 &&  in tty_ldisc_restore()
504 		    tty_ldisc_failto(tty, N_NULL) < 0)  in tty_ldisc_restore()
519 int tty_set_ldisc(struct tty_struct *tty, int disc)  in tty_set_ldisc()  argument
524 	new_ldisc = tty_ldisc_get(tty, disc);  in tty_set_ldisc()
528 	tty_lock(tty);  in tty_set_ldisc()
529 	retval = tty_ldisc_lock(tty, 5 * HZ);  in tty_set_ldisc()
533 	if (!tty->ldisc) {  in tty_set_ldisc()
539 	if (tty->ldisc->ops->num == disc)  in tty_set_ldisc()
542 	if (test_bit(TTY_HUPPED, &tty->flags)) {  in tty_set_ldisc()
548 	old_ldisc = tty->ldisc;  in tty_set_ldisc()
551 	tty_ldisc_close(tty, old_ldisc);  in tty_set_ldisc()
554 	tty->ldisc = new_ldisc;  in tty_set_ldisc()
555 	tty_set_termios_ldisc(tty, disc);  in tty_set_ldisc()
557 	retval = tty_ldisc_open(tty, new_ldisc);  in tty_set_ldisc()
561 		tty_ldisc_restore(tty, old_ldisc);  in tty_set_ldisc()
564 	if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) {  in tty_set_ldisc()
565 		down_read(&tty->termios_rwsem);  in tty_set_ldisc()
566 		tty->ops->set_ldisc(tty);  in tty_set_ldisc()
567 		up_read(&tty->termios_rwsem);  in tty_set_ldisc()
579 	tty_ldisc_unlock(tty);  in tty_set_ldisc()
585 	tty_buffer_restart_work(tty->port);  in tty_set_ldisc()
588 	tty_unlock(tty);  in tty_set_ldisc()
599 static void tty_ldisc_kill(struct tty_struct *tty)  in tty_ldisc_kill()  argument
601 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_kill()
602 	if (!tty->ldisc)  in tty_ldisc_kill()
607 	tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_kill()
608 	tty_ldisc_put(tty->ldisc);  in tty_ldisc_kill()
610 	tty->ldisc = NULL;  in tty_ldisc_kill()
619 static void tty_reset_termios(struct tty_struct *tty)  in tty_reset_termios()  argument
621 	down_write(&tty->termios_rwsem);  in tty_reset_termios()
622 	tty->termios = tty->driver->init_termios;  in tty_reset_termios()
623 	tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);  in tty_reset_termios()
624 	tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);  in tty_reset_termios()
625 	up_write(&tty->termios_rwsem);  in tty_reset_termios()
641 int tty_ldisc_reinit(struct tty_struct *tty, int disc)  in tty_ldisc_reinit()  argument
646 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_reinit()
647 	ld = tty_ldisc_get(tty, disc);  in tty_ldisc_reinit()
653 	if (tty->ldisc) {  in tty_ldisc_reinit()
654 		tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_reinit()
655 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
659 	tty->ldisc = ld;  in tty_ldisc_reinit()
660 	tty_set_termios_ldisc(tty, disc);  in tty_ldisc_reinit()
661 	retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_reinit()
663 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
664 		tty->ldisc = NULL;  in tty_ldisc_reinit()
684 void tty_ldisc_hangup(struct tty_struct *tty, bool reinit)  in tty_ldisc_hangup()  argument
688 	tty_ldisc_debug(tty, "%p: hangup\n", tty->ldisc);  in tty_ldisc_hangup()
690 	ld = tty_ldisc_ref(tty);  in tty_ldisc_hangup()
693 			ld->ops->flush_buffer(tty);  in tty_ldisc_hangup()
694 		tty_driver_flush_buffer(tty);  in tty_ldisc_hangup()
695 		if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&  in tty_ldisc_hangup()
697 			ld->ops->write_wakeup(tty);  in tty_ldisc_hangup()
699 			ld->ops->hangup(tty);  in tty_ldisc_hangup()
703 	wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);  in tty_ldisc_hangup()
704 	wake_up_interruptible_poll(&tty->read_wait, EPOLLIN);  in tty_ldisc_hangup()
712 	tty_ldisc_lock(tty, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_hangup()
714 	if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)  in tty_ldisc_hangup()
715 		tty_reset_termios(tty);  in tty_ldisc_hangup()
717 	if (tty->ldisc) {  in tty_ldisc_hangup()
719 			if (tty_ldisc_reinit(tty, tty->termios.c_line) < 0 &&  in tty_ldisc_hangup()
720 			    tty_ldisc_reinit(tty, N_TTY) < 0)  in tty_ldisc_hangup()
721 				WARN_ON(tty_ldisc_reinit(tty, N_NULL) < 0);  in tty_ldisc_hangup()
723 			tty_ldisc_kill(tty);  in tty_ldisc_hangup()
725 	tty_ldisc_unlock(tty);  in tty_ldisc_hangup()
737 int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)  in tty_ldisc_setup()  argument
739 	int retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_setup()
751 			tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_setup()
765 void tty_ldisc_release(struct tty_struct *tty)  in tty_ldisc_release()  argument
767 	struct tty_struct *o_tty = tty->link;  in tty_ldisc_release()
774 	tty_ldisc_lock_pair(tty, o_tty);  in tty_ldisc_release()
775 	tty_ldisc_kill(tty);  in tty_ldisc_release()
778 	tty_ldisc_unlock_pair(tty, o_tty);  in tty_ldisc_release()
785 	tty_ldisc_debug(tty, "released\n");  in tty_ldisc_release()
795 int tty_ldisc_init(struct tty_struct *tty)  in tty_ldisc_init()  argument
797 	struct tty_ldisc *ld = tty_ldisc_get(tty, N_TTY);  in tty_ldisc_init()
801 	tty->ldisc = ld;  in tty_ldisc_init()
812 void tty_ldisc_deinit(struct tty_struct *tty)  in tty_ldisc_deinit()  argument
815 	if (tty->ldisc)  in tty_ldisc_deinit()
816 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_deinit()
817 	tty->ldisc = NULL;  in tty_ldisc_deinit()