drivers/tty/tty_mutex.c

   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
  13 void __lockfunc 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 }
  20 EXPORT_SYMBOL(tty_lock);
  21
  22 void __lockfunc tty_unlock(struct tty_struct *tty)
  23 {
  24         if (WARN(tty->magic != TTY_MAGIC, "U Bad %p\n", tty))
  25                 return;
  26         mutex_unlock(&tty->legacy_mutex);
  27         tty_kref_put(tty);
  28 }
  29 EXPORT_SYMBOL(tty_unlock);
  30
  31 void __lockfunc tty_lock_slave(struct tty_struct *tty)
  32 {
  33         if (tty && tty != tty->link)
  34                 tty_lock(tty);
  35 }
  36
  37 void __lockfunc tty_unlock_slave(struct tty_struct *tty)
  38 {
  39         if (tty && tty != tty->link)
  40                 tty_unlock(tty);
  41 }
  42
  43 void tty_set_lock_subclass(struct tty_struct *tty)
  44 {
  45         lockdep_set_subclass(&tty->legacy_mutex, TTY_LOCK_SLAVE);
  46 }