linux-kernel - Re: [patch 0/3] Re: tty contention resulting from tty_open_by

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Message-ID: <20170709115745.GC14769@kroah.com>
Date:   Sun, 9 Jul 2017 13:57:45 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Okash Khawaja <okash.khawaja@...il.com>
Cc:     Jiri Slaby <jslaby@...e.com>,
        Samuel Thibault <samuel.thibault@...-lyon.org>,
        Alan Cox <gnomes@...rguk.ukuu.org.uk>,
        linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
        Kirk Reiser <kirk@...sers.ca>,
        Chris Brannon <chris@...-brannons.com>,
        speakup@...ux-speakup.org
Subject: Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device
 export

On Sun, Jul 09, 2017 at 12:41:53PM +0100, Okash Khawaja wrote:
> 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

Looks great, only one tiny comment about the return value from me, and
really, it's not a big deal at all, you can send a patch 4/3 to change
that up if you want.  No one really runs without the tty layer enabled :)

If there are no other objections, I'll queue this up after 4.13-rc1 is
out, nice job.

greg k-h