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/* Legacy tty mutex glue */
 8
 9enum {
10	TTY_MUTEX_NORMAL,
11	TTY_MUTEX_NESTED,
12};
 
 
 
 
 
 
 
13
14/*
15 * Getting the big tty mutex.
16 */
17
18static void __lockfunc tty_lock_nested(struct tty_struct *tty,
19				       unsigned int subclass)
20{
21	if (tty->magic != TTY_MAGIC) {
22		pr_err("L Bad %p\n", tty);
23		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);
 
33}
34EXPORT_SYMBOL(tty_lock);
35
36void __lockfunc tty_unlock(struct tty_struct *tty)
37{
38	if (tty->magic != TTY_MAGIC) {
39		pr_err("U Bad %p\n", tty);
40		WARN_ON(1);
41		return;
42	}
43	mutex_unlock(&tty->legacy_mutex);
44	tty_kref_put(tty);
45}
46EXPORT_SYMBOL(tty_unlock);
47
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);

 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);