#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.
*/
}
EXPORT_SYMBOL(tty_lock);
+int tty_lock_interruptible(struct tty_struct *tty)
+{
+ if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
+ return -EIO;
+ tty_kref_get(tty);
+ return mutex_lock_interruptible(&tty->legacy_mutex);
+}
+
void __lockfunc tty_unlock(struct tty_struct *tty)
{
if (tty->magic != TTY_MAGIC) {
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);
+ if (tty && tty != tty->link)
tty_lock(tty);
- }
}
void __lockfunc tty_unlock_slave(struct tty_struct *tty)
void tty_set_lock_subclass(struct tty_struct *tty)
{
- lockdep_set_subclass(&tty->legacy_mutex, TTY_MUTEX_SLAVE);
+ lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);
}