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