xref: /openbmc/linux/drivers/tty/tty_mutex.c (revision f309532b)
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 
19 /*
20  * Getting the big tty mutex.
21  */
22 void __lockfunc tty_lock(void)
23 {
24 	mutex_lock(&big_tty_mutex);
25 }
26 EXPORT_SYMBOL(tty_lock);
27 
28 void __lockfunc tty_unlock(void)
29 {
30 	mutex_unlock(&big_tty_mutex);
31 }
32 EXPORT_SYMBOL(tty_unlock);
33