linux/drivers/tty/tty_mutex.c
Linus Torvalds f309532bf3 tty: Revert the tty locking series, it needs more work
This reverts the tty layer change to use per-tty locking, because it's
not correct yet, and fixing it will require some more deep surgery.

The main revert is d29f3ef39b ("tty_lock: Localise the lock"), but
there are several smaller commits that built upon it, they also get
reverted here. The list of reverted commits is:

  fde86d3108 - tty: add lockdep annotations
  8f6576ad47 - tty: fix ldisc lock inversion trace
  d3ca8b64b9 - pty: Fix lock inversion
  b1d679afd7 - tty: drop the pty lock during hangup
  abcefe5fc3 - tty/amiserial: Add missing argument for tty_unlock()
  fd11b42e35 - cris: fix missing tty arg in wait_event_interruptible_tty call
  d29f3ef39b - tty_lock: Localise the lock

The revert had a trivial conflict in the 68360serial.c staging driver
that got removed in the meantime.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-02 15:21:43 -07:00

33 lines
659 B
C

#include <linux/tty.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/semaphore.h>
#include <linux/sched.h>
/*
* The 'big tty mutex'
*
* This mutex is taken and released by tty_lock() and tty_unlock(),
* replacing the older big kernel lock.
* It can no longer be taken recursively, and does not get
* released implicitly while sleeping.
*
* Don't use in new code.
*/
static DEFINE_MUTEX(big_tty_mutex);
/*
* Getting the big tty mutex.
*/
void __lockfunc tty_lock(void)
{
mutex_lock(&big_tty_mutex);
}
EXPORT_SYMBOL(tty_lock);
void __lockfunc tty_unlock(void)
{
mutex_unlock(&big_tty_mutex);
}
EXPORT_SYMBOL(tty_unlock);