Commit | Line | Data |
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b07471fa AB |
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 | */ | |
17 | static DEFINE_MUTEX(big_tty_mutex); | |
18 | struct task_struct *__big_tty_mutex_owner; | |
19 | EXPORT_SYMBOL_GPL(__big_tty_mutex_owner); | |
20 | ||
21 | /* | |
22 | * Getting the big tty mutex. | |
23 | */ | |
24 | void __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 | } | |
33 | EXPORT_SYMBOL(tty_lock); | |
34 | ||
35 | void __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 | } | |
44 | EXPORT_SYMBOL(tty_unlock); |