Message-Id: <20170709114153.157783481@gmail.com>
User-Agent: quilt/0.65
Date: Sun, 09 Jul 2017 12:41:53 +0100
From: Okash Khawaja <okash.khawaja@gmail.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>,
        Samuel Thibault <samuel.thibault@ens-lyon.org>,
        Alan Cox <gnomes@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org
Cc: William Hubbs <w.d.hubbs@gmail.com>,
        Chris Brannon <chris@the-brannons.com>, Kirk Reiser <kirk@reisers.ca>,
        speakup@linux-speakup.org, devel@driverdev.osuosl.org
Subject: [patch 0/3] Re: tty contention resulting from tty_open_by_device export
In-Reply-To: <20170708083803.GA23080@kroah.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 868
Lines: 20

On Sat, Jul 08, 2017 at 10:38:03AM +0200, Greg Kroah-Hartman wrote:
> Overall, the idea looks sane to me.  Keeping userspace from opening a
> tty that the kernel has opened internally makes sense, hopefully
> userspace doesn't get too confused when that happens.  I don't think we
> normally return -EBUSY from an open call, have you seen what happens
> with apps when you do this (like minicom?)
>
I tested this wil minincom, picocom and commands like "echo foo >
/dev/ttyS0". They all correctly report "Device or resource busy".

I have addressed all the comments you made. I have also split the patch
into three. Following is summary of each.

Patch 1: introduces the tty_kopen function and checks for TTY_KOPENED
Patch 2: updates speakup code to use tty_kopen instead of
        tty_open_by_driver
Patch 3: reverses the export of tty_open_by_driver

Thanks,
Okash