74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
#include <linux/tty.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kallsyms.h>
|
|
#include <linux/semaphore.h>
|
|
#include <linux/sched.h>
|
|
|
|
/* 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);
|
|
|
|
/*
|
|
* Getting the big tty mutex for a pair of ttys with lock ordering
|
|
* On a non pty/tty pair tty2 can be NULL which is just fine.
|
|
*/
|
|
void __lockfunc tty_lock_pair(struct tty_struct *tty,
|
|
struct tty_struct *tty2)
|
|
{
|
|
if (tty < tty2) {
|
|
tty_lock(tty);
|
|
tty_lock_nested(tty2, TTY_MUTEX_NESTED);
|
|
} else {
|
|
if (tty2 && tty2 != tty)
|
|
tty_lock(tty2);
|
|
tty_lock_nested(tty, TTY_MUTEX_NESTED);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(tty_lock_pair);
|
|
|
|
void __lockfunc tty_unlock_pair(struct tty_struct *tty,
|
|
struct tty_struct *tty2)
|
|
{
|
|
tty_unlock(tty);
|
|
if (tty2 && tty2 != tty)
|
|
tty_unlock(tty2);
|
|
}
|
|
EXPORT_SYMBOL(tty_unlock_pair);
|