Since n_tty_check_unthrottle() is only called from n_tty_read()
which only originates from a userspace read(), the tty count cannot
be 0; the read() guarantees the file descriptor has not yet been
released.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
        if (tty->driver->type == TTY_DRIVER_TYPE_PTY) {
                if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
                        return;
-               if (!tty->count)
-                       return;
                n_tty_kick_worker(tty);
                tty_wakeup(tty->link);
                return;
                tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
                if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
                        break;
-               if (!tty->count)
-                       break;
                n_tty_kick_worker(tty);
                unthrottled = tty_unthrottle_safe(tty);
                if (!unthrottled)