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>
This commit is contained in:
Peter Hurley 2014-11-05 12:12:44 -05:00 committed by Greg Kroah-Hartman
parent 1bc8cde46a
commit 3ee175d9d9

View File

@ -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