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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 | ||
14 | void 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 | } | |
21 | EXPORT_SYMBOL(tty_lock); | |
22 | ||
23 | int 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 | ||
36 | void 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 | } | |
43 | EXPORT_SYMBOL(tty_unlock); | |
44 | ||
45 | void tty_lock_slave(struct tty_struct *tty) | |
46 | { | |
47 | if (tty && tty != tty->link) | |
48 | tty_lock(tty); | |
49 | } | |
50 | ||
51 | void tty_unlock_slave(struct tty_struct *tty) | |
52 | { | |
53 | if (tty && tty != tty->link) | |
54 | tty_unlock(tty); | |
55 | } | |
56 | ||
57 | void tty_set_lock_subclass(struct tty_struct *tty) | |
58 | { | |
59 | lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE); | |
60 | } |