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