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Commit 80e5c4dd authored by Sasha Levin's avatar Sasha Levin
Browse files

Revert "tty: fix stall caused by missing memory barrier in drivers/tty/n_tty.c" 



This reverts commit af32cc7b.

The commit was incorrectly backported and was causing hangs.

Reported-by: default avatarCorey Wright <undefined@pobox.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 8341455f

drivers/tty/n_tty.c

+10 −6
Original line number Original line Diff line number Diff line
@@ -364,7 +364,7 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty) 
	spin_lock_irqsave(&tty->ctrl_lock, flags);

	spin_lock_irqsave(&tty->ctrl_lock, flags);

	if (tty->link->packet) {

	if (tty->link->packet) {

		tty->ctrl_status |= TIOCPKT_FLUSHREAD;

		tty->ctrl_status |= TIOCPKT_FLUSHREAD;

		spin_unlock_irqrestore(&tty->ctrl_lock, flags);

		if (waitqueue_active(&tty->link->read_wait))

			wake_up_interruptible(&tty->link->read_wait);

			wake_up_interruptible(&tty->link->read_wait);

	}

	}

	spin_unlock_irqrestore(&tty->ctrl_lock, flags);

	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
@@ -1387,6 +1387,7 @@ handle_newline: 
			put_tty_queue(c, ldata);

			put_tty_queue(c, ldata);

			ldata->canon_head = ldata->read_head;

			ldata->canon_head = ldata->read_head;

			kill_fasync(&tty->fasync, SIGIO, POLL_IN);

			kill_fasync(&tty->fasync, SIGIO, POLL_IN);

			if (waitqueue_active(&tty->read_wait))

				wake_up_interruptible_poll(&tty->read_wait, POLLIN);

				wake_up_interruptible_poll(&tty->read_wait, POLLIN);

			return 0;

			return 0;

		}

		}
@@ -1670,6 +1671,7 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, 
	if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) ||

	if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) ||

		L_EXTPROC(tty)) {

		L_EXTPROC(tty)) {

		kill_fasync(&tty->fasync, SIGIO, POLL_IN);

		kill_fasync(&tty->fasync, SIGIO, POLL_IN);

		if (waitqueue_active(&tty->read_wait))

			wake_up_interruptible_poll(&tty->read_wait, POLLIN);

			wake_up_interruptible_poll(&tty->read_wait, POLLIN);

	}

	}

}

}
@@ -1889,7 +1891,9 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) 
	}

	}





	/* The termios change make the tty ready for I/O */

	/* The termios change make the tty ready for I/O */

	if (waitqueue_active(&tty->write_wait))

		wake_up_interruptible(&tty->write_wait);

		wake_up_interruptible(&tty->write_wait);

	if (waitqueue_active(&tty->read_wait))

		wake_up_interruptible(&tty->read_wait);

		wake_up_interruptible(&tty->read_wait);

}

}