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#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_SLAVE,
};
/*
* Getting the big tty mutex.
*/
void __lockfunc tty_lock(struct tty_struct *tty)
{
if (tty->magic != TTY_MAGIC) {
pr_err("L Bad %p\n", tty);
WARN_ON(1);
return;
}
tty_kref_get(tty);
mutex_lock(&tty->legacy_mutex);
}
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(tty);
}
}
void __lockfunc tty_unlock_slave(struct tty_struct *tty)
{
if (tty && tty != tty->link)
tty_unlock(tty);
}
void tty_set_lock_subclass(struct tty_struct *tty)
{
lockdep_set_subclass(&tty->legacy_mutex, TTY_MUTEX_SLAVE);
}
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