27 #define tty_ldisc_debug(tty, f, args...)	tty_debug(tty, f, ##args)  argument
29 #define tty_ldisc_debug(tty, f, args...)  argument
140 static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)  in tty_ldisc_get()  argument
168 	ld->tty = tty;  in tty_ldisc_get()
240 struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)  in tty_ldisc_ref_wait()  argument
244 	ldsem_down_read(&tty->ldisc_sem, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_ref_wait()
245 	ld = tty->ldisc;  in tty_ldisc_ref_wait()
247 		ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref_wait()
260 struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)  in tty_ldisc_ref()  argument
264 	if (ldsem_down_read_trylock(&tty->ldisc_sem)) {  in tty_ldisc_ref()
265 		ld = tty->ldisc;  in tty_ldisc_ref()
267 			ldsem_up_read(&tty->ldisc_sem);  in tty_ldisc_ref()
282 	ldsem_up_read(&ld->tty->ldisc_sem);  in tty_ldisc_deref()
288 __tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock()  argument
290 	return ldsem_down_write(&tty->ldisc_sem, timeout);  in __tty_ldisc_lock()
294 __tty_ldisc_lock_nested(struct tty_struct *tty, unsigned long timeout)  in __tty_ldisc_lock_nested()  argument
296 	return ldsem_down_write_nested(&tty->ldisc_sem,  in __tty_ldisc_lock_nested()
300 static inline void __tty_ldisc_unlock(struct tty_struct *tty)  in __tty_ldisc_unlock()  argument
302 	ldsem_up_write(&tty->ldisc_sem);  in __tty_ldisc_unlock()
305 int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout)  in tty_ldisc_lock()  argument
310 	set_bit(TTY_LDISC_CHANGING, &tty->flags);  in tty_ldisc_lock()
311 	wake_up_interruptible_all(&tty->read_wait);  in tty_ldisc_lock()
312 	wake_up_interruptible_all(&tty->write_wait);  in tty_ldisc_lock()
314 	ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock()
317 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock()
321 void tty_ldisc_unlock(struct tty_struct *tty)  in tty_ldisc_unlock()  argument
323 	clear_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_unlock()
325 	clear_bit(TTY_LDISC_CHANGING, &tty->flags);  in tty_ldisc_unlock()
326 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock()
330 tty_ldisc_lock_pair_timeout(struct tty_struct *tty, struct tty_struct *tty2,  in tty_ldisc_lock_pair_timeout()  argument
335 	if (tty < tty2) {  in tty_ldisc_lock_pair_timeout()
336 		ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
340 				__tty_ldisc_unlock(tty);  in tty_ldisc_lock_pair_timeout()
344 		WARN_ON_ONCE(tty == tty2);  in tty_ldisc_lock_pair_timeout()
345 		if (tty2 && tty != tty2) {  in tty_ldisc_lock_pair_timeout()
348 				ret = __tty_ldisc_lock_nested(tty, timeout);  in tty_ldisc_lock_pair_timeout()
353 			ret = __tty_ldisc_lock(tty, timeout);  in tty_ldisc_lock_pair_timeout()
359 	set_bit(TTY_LDISC_HALTED, &tty->flags);  in tty_ldisc_lock_pair_timeout()
365 static void tty_ldisc_lock_pair(struct tty_struct *tty, struct tty_struct *tty2)  in tty_ldisc_lock_pair()  argument
367 	tty_ldisc_lock_pair_timeout(tty, tty2, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_lock_pair()
370 static void tty_ldisc_unlock_pair(struct tty_struct *tty,  in tty_ldisc_unlock_pair()  argument
373 	__tty_ldisc_unlock(tty);  in tty_ldisc_unlock_pair()
385 void tty_ldisc_flush(struct tty_struct *tty)  in tty_ldisc_flush()  argument
387 	struct tty_ldisc *ld = tty_ldisc_ref(tty);  in tty_ldisc_flush()
389 	tty_buffer_flush(tty, ld);  in tty_ldisc_flush()
408 static void tty_set_termios_ldisc(struct tty_struct *tty, int disc)  in tty_set_termios_ldisc()  argument
410 	down_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
411 	tty->termios.c_line = disc;  in tty_set_termios_ldisc()
412 	up_write(&tty->termios_rwsem);  in tty_set_termios_ldisc()
414 	tty->disc_data = NULL;  in tty_set_termios_ldisc()
415 	tty->receive_room = 0;  in tty_set_termios_ldisc()
427 static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_open()  argument
429 	WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_open()
433 		ret = ld->ops->open(tty);  in tty_ldisc_open()
435 			clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_open()
437 		tty_ldisc_debug(tty, "%p: opened\n", ld);  in tty_ldisc_open()
450 static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)  in tty_ldisc_close()  argument
452 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_close()
453 	WARN_ON(!test_bit(TTY_LDISC_OPEN, &tty->flags));  in tty_ldisc_close()
454 	clear_bit(TTY_LDISC_OPEN, &tty->flags);  in tty_ldisc_close()
456 		ld->ops->close(tty);  in tty_ldisc_close()
457 	tty_ldisc_debug(tty, "%p: closed\n", ld);  in tty_ldisc_close()
468 static int tty_ldisc_failto(struct tty_struct *tty, int ld)  in tty_ldisc_failto()  argument
470 	struct tty_ldisc *disc = tty_ldisc_get(tty, ld);  in tty_ldisc_failto()
473 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_failto()
476 	tty->ldisc = disc;  in tty_ldisc_failto()
477 	tty_set_termios_ldisc(tty, ld);  in tty_ldisc_failto()
478 	r = tty_ldisc_open(tty, disc);  in tty_ldisc_failto()
492 static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)  in tty_ldisc_restore()  argument
495 	if (tty_ldisc_failto(tty, old->ops->num) < 0) {  in tty_ldisc_restore()
496 		const char *name = tty_name(tty);  in tty_ldisc_restore()
504 		if (tty_ldisc_failto(tty, N_TTY) < 0 &&  in tty_ldisc_restore()
505 		    tty_ldisc_failto(tty, N_NULL) < 0)  in tty_ldisc_restore()
520 int tty_set_ldisc(struct tty_struct *tty, int disc)  in tty_set_ldisc()  argument
525 	new_ldisc = tty_ldisc_get(tty, disc);  in tty_set_ldisc()
529 	tty_lock(tty);  in tty_set_ldisc()
530 	retval = tty_ldisc_lock(tty, 5 * HZ);  in tty_set_ldisc()
534 	if (!tty->ldisc) {  in tty_set_ldisc()
540 	if (tty->ldisc->ops->num == disc)  in tty_set_ldisc()
543 	if (test_bit(TTY_HUPPED, &tty->flags)) {  in tty_set_ldisc()
549 	old_ldisc = tty->ldisc;  in tty_set_ldisc()
552 	tty_ldisc_close(tty, old_ldisc);  in tty_set_ldisc()
555 	tty->ldisc = new_ldisc;  in tty_set_ldisc()
556 	tty_set_termios_ldisc(tty, disc);  in tty_set_ldisc()
558 	retval = tty_ldisc_open(tty, new_ldisc);  in tty_set_ldisc()
562 		tty_ldisc_restore(tty, old_ldisc);  in tty_set_ldisc()
565 	if (tty->ldisc->ops->num != old_ldisc->ops->num && tty->ops->set_ldisc) {  in tty_set_ldisc()
566 		down_read(&tty->termios_rwsem);  in tty_set_ldisc()
567 		tty->ops->set_ldisc(tty);  in tty_set_ldisc()
568 		up_read(&tty->termios_rwsem);  in tty_set_ldisc()
580 	tty_ldisc_unlock(tty);  in tty_set_ldisc()
586 	tty_buffer_restart_work(tty->port);  in tty_set_ldisc()
589 	tty_unlock(tty);  in tty_set_ldisc()
600 static void tty_ldisc_kill(struct tty_struct *tty)  in tty_ldisc_kill()  argument
602 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_kill()
603 	if (!tty->ldisc)  in tty_ldisc_kill()
608 	tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_kill()
609 	tty_ldisc_put(tty->ldisc);  in tty_ldisc_kill()
611 	tty->ldisc = NULL;  in tty_ldisc_kill()
620 static void tty_reset_termios(struct tty_struct *tty)  in tty_reset_termios()  argument
622 	down_write(&tty->termios_rwsem);  in tty_reset_termios()
623 	tty->termios = tty->driver->init_termios;  in tty_reset_termios()
624 	tty->termios.c_ispeed = tty_termios_input_baud_rate(&tty->termios);  in tty_reset_termios()
625 	tty->termios.c_ospeed = tty_termios_baud_rate(&tty->termios);  in tty_reset_termios()
626 	up_write(&tty->termios_rwsem);  in tty_reset_termios()
642 int tty_ldisc_reinit(struct tty_struct *tty, int disc)  in tty_ldisc_reinit()  argument
647 	lockdep_assert_held_write(&tty->ldisc_sem);  in tty_ldisc_reinit()
648 	ld = tty_ldisc_get(tty, disc);  in tty_ldisc_reinit()
654 	if (tty->ldisc) {  in tty_ldisc_reinit()
655 		tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_reinit()
656 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
660 	tty->ldisc = ld;  in tty_ldisc_reinit()
661 	tty_set_termios_ldisc(tty, disc);  in tty_ldisc_reinit()
662 	retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_reinit()
664 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_reinit()
665 		tty->ldisc = NULL;  in tty_ldisc_reinit()
685 void tty_ldisc_hangup(struct tty_struct *tty, bool reinit)  in tty_ldisc_hangup()  argument
689 	tty_ldisc_debug(tty, "%p: hangup\n", tty->ldisc);  in tty_ldisc_hangup()
691 	ld = tty_ldisc_ref(tty);  in tty_ldisc_hangup()
694 			ld->ops->flush_buffer(tty);  in tty_ldisc_hangup()
695 		tty_driver_flush_buffer(tty);  in tty_ldisc_hangup()
696 		if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) &&  in tty_ldisc_hangup()
698 			ld->ops->write_wakeup(tty);  in tty_ldisc_hangup()
700 			ld->ops->hangup(tty);  in tty_ldisc_hangup()
704 	wake_up_interruptible_poll(&tty->write_wait, EPOLLOUT);  in tty_ldisc_hangup()
705 	wake_up_interruptible_poll(&tty->read_wait, EPOLLIN);  in tty_ldisc_hangup()
713 	tty_ldisc_lock(tty, MAX_SCHEDULE_TIMEOUT);  in tty_ldisc_hangup()
715 	if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS)  in tty_ldisc_hangup()
716 		tty_reset_termios(tty);  in tty_ldisc_hangup()
718 	if (tty->ldisc) {  in tty_ldisc_hangup()
720 			if (tty_ldisc_reinit(tty, tty->termios.c_line) < 0 &&  in tty_ldisc_hangup()
721 			    tty_ldisc_reinit(tty, N_TTY) < 0)  in tty_ldisc_hangup()
722 				WARN_ON(tty_ldisc_reinit(tty, N_NULL) < 0);  in tty_ldisc_hangup()
724 			tty_ldisc_kill(tty);  in tty_ldisc_hangup()
726 	tty_ldisc_unlock(tty);  in tty_ldisc_hangup()
738 int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)  in tty_ldisc_setup()  argument
740 	int retval = tty_ldisc_open(tty, tty->ldisc);  in tty_ldisc_setup()
752 			tty_ldisc_close(tty, tty->ldisc);  in tty_ldisc_setup()
766 void tty_ldisc_release(struct tty_struct *tty)  in tty_ldisc_release()  argument
768 	struct tty_struct *o_tty = tty->link;  in tty_ldisc_release()
775 	tty_ldisc_lock_pair(tty, o_tty);  in tty_ldisc_release()
776 	tty_ldisc_kill(tty);  in tty_ldisc_release()
779 	tty_ldisc_unlock_pair(tty, o_tty);  in tty_ldisc_release()
786 	tty_ldisc_debug(tty, "released\n");  in tty_ldisc_release()
796 int tty_ldisc_init(struct tty_struct *tty)  in tty_ldisc_init()  argument
798 	struct tty_ldisc *ld = tty_ldisc_get(tty, N_TTY);  in tty_ldisc_init()
802 	tty->ldisc = ld;  in tty_ldisc_init()
813 void tty_ldisc_deinit(struct tty_struct *tty)  in tty_ldisc_deinit()  argument
816 	if (tty->ldisc)  in tty_ldisc_deinit()
817 		tty_ldisc_put(tty->ldisc);  in tty_ldisc_deinit()
818 	tty->ldisc = NULL;  in tty_ldisc_deinit()