From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Hurley <peter@hurleysoftware.com>
Subject: Re: [Fwd: [PATCH v2 0/4] TTY: port hangup and close fixes]
Date: Tue, 05 Mar 2013 17:02:56 -0500
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	 <1362503170.18799.33.camel@thor.lan> <51366A29.2060808@suse.cz>
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To: Jiri Slaby <jslaby@suse.cz>
Cc: jhovold@gmail.com, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Alan Stern <stern@rowland.harvard.edu>, USB list <linux-usb@vger.kernel.org>, linux-serial@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>, LKML <linux-kernel@vger.kernel.org>
List-Id: linux-serial@vger.kernel.org

On Tue, 2013-03-05 at 22:56 +0100, Jiri Slaby wrote:
> On 03/05/2013 06:06 PM, Peter Hurley wrote:
> >>> @@ -225,15 +232,13 @@ void tty_port_hangup(struct tty_port *port)
> >>         spin_lock_irqsave(&port->lock, flags);
> >>         port->count = 0;
> >>         port->flags &= ~ASYNC_NORMAL_ACTIVE;
> >> -       if (port->tty) {
> >> +       if (port->tty)
> >>                 set_bit(TTY_IO_ERROR, &port->tty->flags);
> >> -               tty_kref_put(port->tty);
> >> -       }
> >> -       port->tty = NULL;
> >>         spin_unlock_irqrestore(&port->lock, flags);
> >>> +       tty_port_shutdown(port, port->tty);
> >>
> >> What prevents port->tty to be NULL here already?
> > 
> > Nothing. That's why it's tested in tty_port_shutdown() above.
> 
> I know :).

Sorry :)

> But the question is rather don't we want to pass the real
> refcounted port->tty (take a snapshot inside the lock) instead?

I think that's why he moved the kref release to after the shutdown (via
tty_port_set_tty()) -- but I'm tired and maybe I'm missing something
here?

Regards,
Peter Hurley