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Commit 63d8cb3f authored by Peter Hurley's avatar Peter Hurley Committed by Greg Kroah-Hartman
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tty: Simplify tty_set_ldisc() exit handling 



Perform common exit for both successful and error exit handling
in tty_set_ldisc(). Fixes unlikely possibility of failing to restart
input kworker when switching to the same line discipline (noop case).

Signed-off-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5841fc4b

drivers/tty/tty_ldisc.c

+13 −29
Original line number Diff line number Diff line
@@ -529,34 +529,21 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) 


	tty_lock(tty);

	retval = tty_ldisc_lock(tty, 5 * HZ);

	if (retval) {

		tty_ldisc_put(new_ldisc);

		tty_unlock(tty);

		return retval;

	}

	if (retval)

		goto err;



	/*

	 *	Check the no-op case

	 */

	/* Check the no-op case */

	if (tty->ldisc->ops->num == ldisc)

		goto out;



	if (tty->ldisc->ops->num == ldisc) {

		tty_ldisc_unlock(tty);

		tty_ldisc_put(new_ldisc);

		tty_unlock(tty);

		return 0;

	if (test_bit(TTY_HUPPED, &tty->flags)) {

		/* We were raced by hangup */

		retval = -EIO;

		goto out;

	}



	old_ldisc = tty->ldisc;



	if (test_bit(TTY_HUPPED, &tty->flags)) {

		/* We were raced by the hangup method. It will have stomped

		   the ldisc data and closed the ldisc down */

		tty_ldisc_unlock(tty);

		tty_ldisc_put(new_ldisc);

		tty_unlock(tty);

		return -EIO;

	}



	/* Shutdown the old discipline. */

	tty_ldisc_close(tty, old_ldisc);
@@ -582,18 +569,15 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc) 
	   the old ldisc (if it was restored as part of error cleanup

	   above). In either case, releasing a single reference from

	   the old ldisc is correct. */



	tty_ldisc_put(old_ldisc);



	/*

	 *	Allow ldisc referencing to occur again

	 */

	new_ldisc = old_ldisc;

out:

	tty_ldisc_unlock(tty);



	/* Restart the work queue in case no characters kick it off. Safe if

	   already running */

	tty_buffer_restart_work(tty->port);



err:

	tty_ldisc_put(new_ldisc);	/* drop the extra reference */

	tty_unlock(tty);

	return retval;

}