blob: f43e995c7a0fc8a64ae1ee41eb2c7afa418df5b4 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
#include <linux/tty.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/semaphore.h>
#include <linux/sched.h>
/*
* Nested tty locks are necessary for releasing pty pairs.
* The stable lock order is master pty first, then slave pty.
*/
/* Legacy tty mutex glue */
enum {
TTY_MUTEX_NORMAL,
TTY_MUTEX_NESTED,
};
/*
* Getting the big tty mutex.
*/
static void __lockfunc tty_lock_nested(struct tty_struct *tty,
unsigned int subclass)
{
if (tty->magic != TTY_MAGIC) {
pr_err("L Bad %p\n", tty);
WARN_ON(1);
return;
}
tty_kref_get(tty);
mutex_lock_nested(&tty->legacy_mutex, subclass);
}
void __lockfunc tty_lock(struct tty_struct *tty)
{
return tty_lock_nested(tty, TTY_MUTEX_NORMAL);
}
EXPORT_SYMBOL(tty_lock);
void __lockfunc tty_unlock(struct tty_struct *tty)
{
if (tty->magic != TTY_MAGIC) {
pr_err("U Bad %p\n", tty);
WARN_ON(1);
return;
}
mutex_unlock(&tty->legacy_mutex);
tty_kref_put(tty);
}
EXPORT_SYMBOL(tty_unlock);
void __lockfunc tty_lock_slave(struct tty_struct *tty)
{
if (tty && tty != tty->link) {
WARN_ON(!mutex_is_locked(&tty->link->legacy_mutex) ||
!tty->driver->type == TTY_DRIVER_TYPE_PTY ||
!tty->driver->type == PTY_TYPE_SLAVE);
tty_lock_nested(tty, TTY_MUTEX_NESTED);
}
}
void __lockfunc tty_unlock_slave(struct tty_struct *tty)
{
if (tty && tty != tty->link)
tty_unlock(tty);
}
|
