LXR linux/drivers/tty/tty

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/tty.h>
   3#include <linux/module.h>
   4#include <linux/kallsyms.h>
   5#include <linux/semaphore.h>
   6#include <linux/sched.h>
   7
   8/* Legacy tty mutex glue */
   9
  10/*
  11 * Getting the big tty mutex.
  12 */
  13
  14void tty_lock(struct tty_struct *tty)
  15{
  16        if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
  17                return;
  18        tty_kref_get(tty);
  19        mutex_lock(&tty->legacy_mutex);
  20}
  21EXPORT_SYMBOL(tty_lock);
  22
  23int tty_lock_interruptible(struct tty_struct *tty)
  24{
  25        int ret;
  26
  27        if (WARN(tty->magic != TTY_MAGIC, "L Bad %p\n", tty))
  28                return -EIO;
  29        tty_kref_get(tty);
  30        ret = mutex_lock_interruptible(&tty->legacy_mutex);
  31        if (ret)
  32                tty_kref_put(tty);
  33        return ret;
  34}
  35
  36void tty_unlock(struct tty_struct *tty)
  37{
  38        if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty))
  39                return;
  40        mutex_unlock(&tty->legacy_mutex);
  41        tty_kref_put(tty);
  42}
  43EXPORT_SYMBOL(tty_unlock);
  44
  45void tty_lock_slave(struct tty_struct *tty)
  46{
  47        if (tty && tty != tty->link)
  48                tty_lock(tty);
  49}
  50
  51void tty_unlock_slave(struct tty_struct *tty)
  52{
  53        if (tty && tty != tty->link)
  54                tty_unlock(tty);
  55}
  56
  57void tty_set_lock_subclass(struct tty_struct *tty)
  58{
  59        lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);
  60}
  61