tty: Remove warning in tty_lock_slave()

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@oracle.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c
index 4486741190c47d52d8079f360081d99085ce82c4..a872389dc0bcd8309c6138057c90c9c0abf1f089 100644 (file)
--- 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)