From 3ee175d9d9f9be0e345f7237ee921e58f68afdd7 Mon Sep 17 00:00:00 2001 From: Peter Hurley <peter@hurleysoftware.com> Date: Wed, 5 Nov 2014 12:12:44 -0500 Subject: [PATCH] tty: Don't hold tty_lock for ldisc release The tty->ldisc_sem write lock is sufficient for serializing changes to tty->ldisc; holding the tty lock is not required. Reviewed-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/tty/tty_ldisc.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c index 2d822aa259b2..332a622b7203 100644 --- a/drivers/tty/tty_ldisc.c +++ b/drivers/tty/tty_ldisc.c @@ -764,6 +764,8 @@ static void tty_ldisc_kill(struct tty_struct *tty) * Called during the final close of a tty/pty pair in order to shut down * the line discpline layer. On exit the ldisc assigned is N_TTY and the * ldisc has not been opened. + * + * Holding ldisc_sem write lock serializes tty->ldisc changes. */ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) @@ -776,13 +778,9 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty) tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc); tty_ldisc_lock_pair(tty, o_tty); - tty_lock_pair(tty, o_tty); - tty_ldisc_kill(tty); if (o_tty) tty_ldisc_kill(o_tty); - - tty_unlock_pair(tty, o_tty); tty_ldisc_unlock_pair(tty, o_tty); /* And the memory resources remaining (buffers, termios) will be