blob: 2e41abebbcbaef923c38a4ea6c3cee56dd6fe9fd [file] [log] [blame]
Arnd Bergmannb07471f2010-08-06 21:40:30 +02001#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
Alan Cox89c8d912012-08-08 16:30:13 +01007/* Legacy tty mutex glue */
8
9enum {
10 TTY_MUTEX_NORMAL,
11 TTY_MUTEX_NESTED,
12};
Eric Dumazetfde86d32012-05-31 11:35:18 +020013
Arnd Bergmannb07471f2010-08-06 21:40:30 +020014/*
15 * Getting the big tty mutex.
16 */
Alan Cox89c8d912012-08-08 16:30:13 +010017
18static void __lockfunc tty_lock_nested(struct tty_struct *tty,
19 unsigned int subclass)
Arnd Bergmannb07471f2010-08-06 21:40:30 +020020{
Alan Cox89c8d912012-08-08 16:30:13 +010021 if (tty->magic != TTY_MAGIC) {
Sangho Yi7a0c4ed2012-10-18 00:15:13 +090022 pr_err("L Bad %p\n", tty);
Alan Cox89c8d912012-08-08 16:30:13 +010023 WARN_ON(1);
24 return;
25 }
26 tty_kref_get(tty);
27 mutex_lock_nested(&tty->legacy_mutex, subclass);
28}
29
30void __lockfunc tty_lock(struct tty_struct *tty)
31{
32 return tty_lock_nested(tty, TTY_MUTEX_NORMAL);
Arnd Bergmannb07471f2010-08-06 21:40:30 +020033}
34EXPORT_SYMBOL(tty_lock);
35
Alan Cox89c8d912012-08-08 16:30:13 +010036void __lockfunc tty_unlock(struct tty_struct *tty)
Arnd Bergmannb07471f2010-08-06 21:40:30 +020037{
Alan Cox89c8d912012-08-08 16:30:13 +010038 if (tty->magic != TTY_MAGIC) {
Sangho Yi7a0c4ed2012-10-18 00:15:13 +090039 pr_err("U Bad %p\n", tty);
Alan Cox89c8d912012-08-08 16:30:13 +010040 WARN_ON(1);
41 return;
42 }
43 mutex_unlock(&tty->legacy_mutex);
44 tty_kref_put(tty);
Arnd Bergmannb07471f2010-08-06 21:40:30 +020045}
46EXPORT_SYMBOL(tty_unlock);
Alan Cox89c8d912012-08-08 16:30:13 +010047
48/*
49 * Getting the big tty mutex for a pair of ttys with lock ordering
50 * On a non pty/tty pair tty2 can be NULL which is just fine.
51 */
52void __lockfunc tty_lock_pair(struct tty_struct *tty,
53 struct tty_struct *tty2)
54{
55 if (tty < tty2) {
56 tty_lock(tty);
57 tty_lock_nested(tty2, TTY_MUTEX_NESTED);
58 } else {
59 if (tty2 && tty2 != tty)
60 tty_lock(tty2);
61 tty_lock_nested(tty, TTY_MUTEX_NESTED);
62 }
63}
64EXPORT_SYMBOL(tty_lock_pair);
65
66void __lockfunc tty_unlock_pair(struct tty_struct *tty,
67 struct tty_struct *tty2)
68{
69 tty_unlock(tty);
70 if (tty2 && tty2 != tty)
71 tty_unlock(tty2);
72}
73EXPORT_SYMBOL(tty_unlock_pair);