1#include <linux/tty.h>
 2#include <linux/module.h>
 3#include <linux/kallsyms.h>
 4#include <linux/semaphore.h>
 5#include <linux/sched.h>
 
 6
 7/*
 8 * The 'big tty mutex'
 9 *
10 * This mutex is taken and released by tty_lock() and tty_unlock(),
11 * replacing the older big kernel lock.
12 * It can no longer be taken recursively, and does not get
13 * released implicitly while sleeping.
14 *
15 * Don't use in new code.
16 */
17static DEFINE_MUTEX(big_tty_mutex);
18struct task_struct *__big_tty_mutex_owner;
19EXPORT_SYMBOL_GPL(__big_tty_mutex_owner);
20
21/*
22 * Getting the big tty mutex.
23 */
24void __lockfunc tty_lock(void)
25{
26	struct task_struct *task = current;
27
28	WARN_ON(__big_tty_mutex_owner == task);
29
30	mutex_lock(&big_tty_mutex);
31	__big_tty_mutex_owner = task;
 
 
 
 
32}
33EXPORT_SYMBOL(tty_lock);
34
35void __lockfunc tty_unlock(void)
36{
37	struct task_struct *task = current;
38
39	WARN_ON(__big_tty_mutex_owner != task);
40	__big_tty_mutex_owner = NULL;
 
 
 
 
 
 
41
42	mutex_unlock(&big_tty_mutex);
 
 
 
 
 
43}
44EXPORT_SYMBOL(tty_unlock);

 1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/tty.h>
 3#include <linux/module.h>
 4#include <linux/kallsyms.h>
 5#include <linux/semaphore.h>
 6#include <linux/sched.h>
 7#include "tty.h"
 8
 9/* Legacy tty mutex glue */
 
 
 
 
 
 
 
 
 
 
 
 
10
11/*
12 * Getting the big tty mutex.
13 */
 
 
 
 
 
14
15void tty_lock(struct tty_struct *tty)
16{
17	if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
18		return;
19	tty_kref_get(tty);
20	mutex_lock(&tty->legacy_mutex);
21}
22EXPORT_SYMBOL(tty_lock);
23
24int tty_lock_interruptible(struct tty_struct *tty)
25{
26	int ret;
27
28	if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
29		return -EIO;
30	tty_kref_get(tty);
31	ret = mutex_lock_interruptible(&tty->legacy_mutex);
32	if (ret)
33		tty_kref_put(tty);
34	return ret;
35}
36
37void tty_unlock(struct tty_struct *tty)
38{
39	if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty))
40		return;
41	mutex_unlock(&tty->legacy_mutex);
42	tty_kref_put(tty);
43}
44EXPORT_SYMBOL(tty_unlock);
45
46void tty_lock_slave(struct tty_struct *tty)
47{
48	if (tty && tty != tty->link)
49		tty_lock(tty);
50}
51
52void tty_unlock_slave(struct tty_struct *tty)
53{
54	if (tty && tty != tty->link)
55		tty_unlock(tty);
56}
57
58void tty_set_lock_subclass(struct tty_struct *tty)
59{
60	lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);
61}