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

Greg Kroah-Hartman
2015-03-04T06:43:13Z

From: Peter Hurley <peter@hurleysoftware.com>

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>

---
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)