LXR linux/drivers/tty/tty

   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/* Legacy tty mutex glue */
   8
   9/*
  10 * Getting the big tty mutex.
  11 */
  12
  13void tty_lock(struct tty_struct *tty)
  14{
  15        if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
  16                return;
  17        tty_kref_get(tty);
  18        mutex_lock(&tty->legacy_mutex);
  19}
  20EXPORT_SYMBOL(tty_lock);
  21
  22int tty_lock_interruptible(struct tty_struct *tty)
  23{
  24        int ret;
  25
  26        if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
  27                return -EIO;
  28        tty_kref_get(tty);
  29        ret = mutex_lock_interruptible(&tty->legacy_mutex);
  30        if (ret)
  31                tty_kref_put(tty);
  32        return ret;
  33}
  34
  35void tty_unlock(struct tty_struct *tty)
  36{
  37        if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty))
  38                return;
  39        mutex_unlock(&tty->legacy_mutex);
  40        tty_kref_put(tty);
  41}
  42EXPORT_SYMBOL(tty_unlock);
  43
  44void tty_lock_slave(struct tty_struct *tty)
  45{
  46        if (tty && tty != tty->link)
  47                tty_lock(tty);
  48}
  49
  50void tty_unlock_slave(struct tty_struct *tty)
  51{
  52        if (tty && tty != tty->link)
  53                tty_unlock(tty);
  54}
  55
  56void tty_set_lock_subclass(struct tty_struct *tty)
  57{
  58        lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);
  59}
  60