[patch 0/3] Re: tty contention resulting from tty_open_by_device export

From	Okash Khawaja <okash.khawaja@gmail.com>
Newsgroups	linux.kernel
Subject	[patch 0/3] Re: tty contention resulting from tty_open_by_device export
Date	2017-07-09 13:50 +0200
Message-ID	<u1iSR-7ch-3@gated-at.bofh.it> (permalink)
References	<u0Trr-8hs-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

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

Thread

tty contention resulting from tty_open_by_device export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-07 22:30 +0200
  Re: tty contention resulting from tty_open_by_device export Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-08 10:40 +0200
    Re: tty contention resulting from tty_open_by_device export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-08 11:10 +0200
    [patch 3/3] tty: undo export of tty_open_by_driver Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-09 13:50 +0200
    [patch 0/3] Re: tty contention resulting from tty_open_by_device export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-09 13:50 +0200
      [patch 2/3] staging: speakup: use tty_kopen instead of tty_open_by_driver Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-09 13:50 +0200
        Re: [patch 2/3] staging: speakup: use tty_kopen instead of  tty_open_by_driver Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-09 14:00 +0200
          Re: [patch 2/3] staging: speakup: use tty_kopen instead of  tty_open_by_driver Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-09 14:30 +0200
      [patch 1/3] tty: resolve tty contention between kernel and user space Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-09 13:50 +0200
        Re: [patch 1/3] tty: resolve tty contention between kernel and user  space Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-09 14:00 +0200
        Re: [patch 1/3] tty: resolve tty contention between kernel and user space Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-09 17:10 +0200
          Re: [patch 1/3] tty: resolve tty contention between kernel and user  space Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-09 21:10 +0200
          Re: [patch 1/3] tty: resolve tty contention between kernel and user  space Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-10 10:40 +0200
            Re: [patch 1/3] tty: resolve tty contention between kernel and user space Andy Shevchenko <andy.shevchenko@gmail.com> - 2017-07-10 17:30 +0200
              Re: [patch 1/3] tty: resolve tty contention between kernel and user  space Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-10 18:20 +0200
      Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device  export Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-09 14:00 +0200
      [patch 4/3] tty: make tty_kopen return ENODEV in case of no TTY Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-09 14:40 +0200
      Re: [patch 0/3] Re: tty contention resulting from  tty_open_by_device export Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-07-10 14:00 +0200
        Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device  export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-10 14:40 +0200
          Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device  export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-10 18:30 +0200
          Re: [patch 0/3] Re: tty contention resulting from  tty_open_by_device export Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-07-12 20:30 +0200
            Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device  export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-13 13:40 +0200
              Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device  export Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-07-17 14:40 +0200
                Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-17 15:30 +0200
                Re: [patch 0/3] Re: tty contention resulting from  tty_open_by_device export Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-07-18 00:10 +0200
                [patch v2 1/3] tty: resolve tty contention between kernel and user space Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-17 23:10 +0200
                [patch v2 3/3] tty: undo export of tty_open_by_driver Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-17 23:10 +0200
                [patch v2 0/3] tty contention resulting from tty_open_by_driver export Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-17 23:10 +0200
                [patch v2 2/3] staging: speakup: use tty_kopen instead of tty_open_by_driver Okash Khawaja <okash.khawaja@gmail.com> - 2017-07-17 23:10 +0200

csiph-web