[PATCH 3.19 112/175] tty: Remove warning in tty_lock_slave()

[Greg Kroah-Hartman]

3.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>

commit eef15e2a54fad4c2ce3f0a81485dc591ce678f4f upstream.

Commit 2aff5e2bc62db43e05c814461a08aff0fc2b7fe5 ('tty: Change
tty lock order to master->slave') added a warning which is broken
and unnecessary now that the tty lock has fixed lock subclasses,
added in commit 2febdb632bb96235b94b8fccaf882a78f8f4b2bb
('tty: Preset lock subclass for nested tty locks').

Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/tty/tty_mutex.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

--- a/drivers/tty/tty_mutex.c
+++ b/drivers/tty/tty_mutex.c
@@ -46,12 +46,8 @@ EXPORT_SYMBOL(tty_unlock);
 
 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)


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