[PATCH 00/12] Rework tty_reopen()

[Peter Hurley]

Hi Greg,

This patch series implements two important improvements to tty open()
behavior: interruptible open() and automatic retry when tty teardown
has already commenced.

Interruptible open() allows signals to cancel the open wait if stalled
waiting for tty teardown to complete.

Automatic retry of tty open() when racing a tty teardown now makes tty
open() fully POSIX compliant. For some time, the Linux kernel has
returned EIO from open() under certain circumstances. This happens when
tty_open() observes a valid tty from driver lookup but the tty is
being released (in final close) and teardown is about to commence.

The observable userspace change is that userspace will no longer need
to retry open() on EIO error.

This series also continues the ongoing effort to cleanup and reduce the
kernel tty interface.

Lastly, this series lays important groundwork for implementing ptmx_open()
in tty_open(), trivially with driver lookup (still a work-in-progress).

Regards,

Peter Hurley (12):
  tty: Fix ldisc leak in failed tty_init_dev()
  tty: Remove !tty check from free_tty_struct()
  tty: Fix tty_init_termios() declaration
  tty: Re-declare tty_driver_remove_tty() file scope
  pty: Remove pty_unix98_shutdown()
  tty: Remove __lockfunc annotation from tty lock functions
  tty: Wait interruptibly for tty lock on reopen
  pty: Prepare to redefine tty driver remove() interface
  tty: Re-define tty driver remove() interface
  tty: Consolidate noctty checks in tty_open()
  tty: Refactor tty_open()
  tty: Retry failed reopen if tty teardown in-progress

 drivers/tty/pty.c            |  40 +++-------
 drivers/tty/tty_io.c         | 180 +++++++++++++++++++++----------------------
 drivers/tty/tty_ldisc.c      |  21 +++--
 drivers/tty/tty_mutex.c      |  16 +++-
 drivers/usb/serial/console.c |   6 +-
 include/linux/tty.h          |  19 ++---
 include/linux/tty_driver.h   |   4 +-
 7 files changed, 128 insertions(+), 158 deletions(-)

-- 
2.6.3

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