On 03/20/2011 10:58 PM, Alan Cox wrote: >> + spin_lock_irqsave(&dc->spin_mutex, flags); >> if (port->port.count) >> room = kfifo_avail(&port->fifo_ul); >> - mutex_unlock(&port->tty_sem); >> + spin_unlock_irqrestore(&dc->spin_mutex, flags); > > dc->spin_mutex does not protect port->port.count. Neither port->tty_sem did. Anyway is the test needed at all? I.e. could tty->ops->write/chars_in_buffer/ntty_write_room be called with port->port.count == 0 at all? And the lock should not as well be needed. Kfifo assures atomicity where there is only one reader and one writer which should be the case here. Unless tty->ops->write can be called in parallel. And it should not, that's what's tty->atomic_write_lock for. thanks, -- js suse labs -- To unsubscribe from this list: send the line "unsubscribe linux-ppp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
