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#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);
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