// SPDX-License-Identifier: GPL-2.0#include <linux/tty.h>#include <linux/module.h>#include <linux/kallsyms.h>#include <linux/semaphore.h>#include <linux/sched.h>#include "tty.h" /* Legacy tty mutex glue */ /* * Getting the big tty mutex. */ void tty_lock(struct tty_struct *tty){	tty_kref_get(tty);	mutex_lock(&tty->legacy_mutex);}EXPORT_SYMBOL(tty_lock); int tty_lock_interruptible(struct tty_struct *tty){	int ret; 	tty_kref_get(tty);	ret = mutex_lock_interruptible(&tty->legacy_mutex);	if (ret)		tty_kref_put(tty);	return ret;} void tty_unlock(struct tty_struct *tty){	mutex_unlock(&tty->legacy_mutex);	tty_kref_put(tty);}EXPORT_SYMBOL(tty_unlock); void tty_lock_slave(struct tty_struct *tty){	if (tty && tty != tty->link)		tty_lock(tty);} void tty_unlock_slave(struct tty_struct *tty){	if (tty && tty != tty->link)		tty_unlock(tty);} void tty_set_lock_subclass(struct tty_struct *tty){	lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);}