linux-toradex.git/drivers/tty/tty_ldisc.c, branch v3.7.3

Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2012-10-02T16:54:49+00:00

Pull workqueue changes from Tejun Heo:
 "This is workqueue updates for v3.7-rc1.  A lot of activities this
  round including considerable API and behavior cleanups.

   * delayed_work combines a timer and a work item.  The handling of the
     timer part has always been a bit clunky leading to confusing
     cancelation API with weird corner-case behaviors.  delayed_work is
     updated to use new IRQ safe timer and cancelation now works as
     expected.

   * Another deficiency of delayed_work was lack of the counterpart of
     mod_timer() which led to cancel+queue combinations or open-coded
     timer+work usages.  mod_delayed_work[_on]() are added.

     These two delayed_work changes make delayed_work provide interface
     and behave like timer which is executed with process context.

   * A work item could be executed concurrently on multiple CPUs, which
     is rather unintuitive and made flush_work() behavior confusing and
     half-broken under certain circumstances.  This problem doesn't
     exist for non-reentrant workqueues.  While non-reentrancy check
     isn't free, the overhead is incurred only when a work item bounces
     across different CPUs and even in simulated pathological scenario
     the overhead isn't too high.

     All workqueues are made non-reentrant.  This removes the
     distinction between flush_[delayed_]work() and
     flush_[delayed_]_work_sync().  The former is now as strong as the
     latter and the specified work item is guaranteed to have finished
     execution of any previous queueing on return.

   * In addition to the various bug fixes, Lai redid and simplified CPU
     hotplug handling significantly.

   * Joonsoo introduced system_highpri_wq and used it during CPU
     hotplug.

  There are two merge commits - one to pull in IRQ safe timer from
  tip/timers/core and the other to pull in CPU hotplug fixes from
  wq/for-3.6-fixes as Lai's hotplug restructuring depended on them."

Fixed a number of trivial conflicts, but the more interesting conflicts
were silent ones where the deprecated interfaces had been used by new
code in the merge window, and thus didn't cause any real data conflicts.

Tejun pointed out a few of them, I fixed a couple more.

* 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits)
  workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending()
  workqueue: use cwq_set_max_active() helper for workqueue_set_max_active()
  workqueue: introduce cwq_set_max_active() helper for thaw_workqueues()
  workqueue: remove @delayed from cwq_dec_nr_in_flight()
  workqueue: fix possible stall on try_to_grab_pending() of a delayed work item
  workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback()
  workqueue: use __cpuinit instead of __devinit for cpu callbacks
  workqueue: rename manager_mutex to assoc_mutex
  workqueue: WORKER_REBIND is no longer necessary for idle rebinding
  workqueue: WORKER_REBIND is no longer necessary for busy rebinding
  workqueue: reimplement idle worker rebinding
  workqueue: deprecate __cancel_delayed_work()
  workqueue: reimplement cancel_delayed_work() using try_to_grab_pending()
  workqueue: use mod_delayed_work() instead of __cancel + queue
  workqueue: use irqsafe timer for delayed_work
  workqueue: clean up delayed_work initializers and add missing one
  workqueue: make deferrable delayed_work initializer names consistent
  workqueue: cosmetic whitespace updates for macro definitions
  workqueue: deprecate system_nrt[_freezable]_wq
  workqueue: deprecate flush[_delayed]_work_sync()
  ...

workqueue: deprecate flush[_delayed]_work_sync()

2012-08-20T21:51:24+00:00

flush[_delayed]_work_sync() are now spurious.  Mark them deprecated
and convert all users to flush[_delayed]_work().

If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant and the regular flushes guarantee that the work item is
not pending or running on any CPU on return, so there's no reason to
use the sync flushes at all and they're going away.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo 
Cc: Russell King 
Cc: Paul Mundt 
Cc: Ian Campbell 
Cc: Jens Axboe 
Cc: Mattia Dongili 
Cc: Kent Yoder 
Cc: David Airlie 
Cc: Jiri Kosina 
Cc: Karsten Keil 
Cc: Bryan Wu 
Cc: Benjamin Herrenschmidt 
Cc: Alasdair Kergon 
Cc: Mauro Carvalho Chehab 
Cc: Florian Tobias Schandinat 
Cc: David Woodhouse 
Cc: "David S. Miller" 
Cc: linux-wireless@vger.kernel.org
Cc: Anton Vorontsov 
Cc: Sangbeom Kim 
Cc: "James E.J. Bottomley" 
Cc: Greg Kroah-Hartman 
Cc: Eric Van Hensbergen 
Cc: Takashi Iwai 
Cc: Steven Whitehouse 
Cc: Petr Vandrovec 
Cc: Mark Fasheh 
Cc: Christoph Hellwig 
Cc: Avi Kivity

tty: localise the lock

2012-08-10T19:55:47+00:00

The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.

This contains pieces folded in from the fixes made to the original patches

| From: Geert Uytterhoeven 	(fix m68k)
| From: Paul Gortmaker 	(fix cris)
| From: Jiri Kosina 			(lockdep)
| From: Eric Dumazet 		(lockdep)

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: Fix race in tty release

2012-07-27T18:55:59+00:00

Ian Abbott found that the tty layer would explode with the right set of
parallel open and close operations. This is because we race in the
handling of tty->drivers->termios[].

Correct this by
	Making tty_ldisc_release behave like nromal code (takes the lock,
			does stuff, drops the lock)
	Drop the tty lock earlier in tty_ldisc_release
	Taking the tty mutex around the driver->termios update in all cases
	Adding a WARN_ON to catch future screwups.

I also forgot to clean up the pty resources properly. With a pty pair we
need to pull both halves out of the tables.

Signed-off-by: Alan Cox 
Tested-by: Ian Abbott 
Signed-off-by: Greg Kroah-Hartman

tty ldisc: Close/Reopen race prevention should check the proper flag

2012-07-26T20:37:06+00:00

Commit acfa747b introduced the TTY_HUPPING flag to distinguish
closed TTY from currently closing ones. The test in tty_set_ldisc
still remained pointing at the old flag. This causes pppd to
sometimes lapse into uninterruptible sleep when killed and
restarted.

Signed-off-by: Shachar Shemesh 
Signed-off-by: Greg Kroah-Hartman

tty: move the termios object into the tty

2012-07-16T20:00:41+00:00

This will let us sort out a whole pile of tty related races. The
alternative would be to keep points and refcount the termios objects.
However
1. They are tiny anyway
2. Many devices don't use the stored copies
3. We can remove a pty special case

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: revert incorrectly applied lock patch

2012-07-16T19:58:12+00:00

I sent GregKH this after the pre-requisites. He dropped the pre-requesites
for good reason and unfortunately then applied this patch. Without this
reverted you get random kernel memory corruption which will make bisecting
anything between it and the properly applied patches a complete sod.

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty ldisc: Close/Reopen race prevention should check the proper flag

2012-07-12T21:54:14+00:00

Commit acfa747b introduced the TTY_HUPPING flag to distinguish
closed TTY from currently closing ones. The test in tty_set_ldisc
still remained pointing at the old flag. This causes pppd to
sometimes lapse into uninterruptible sleep when killed and
restarted.

Signed-off-by: Shachar Shemesh 
Signed-off-by: Greg Kroah-Hartman

tty: localise the lock

2012-07-06T21:24:52+00:00

The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.

This contains pieces folded in from the fixes made to the original patches

| From: Geert Uytterhoeven 	(fix m68k)
| From: Paul Gortmaker 	(fix cris)
| From: Jiri Kosina 			(lockdep)
| From: Eric Dumazet 		(lockdep)

Signed-off-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

tty: Revert the tty locking series, it needs more work

2012-06-02T22:21:43+00:00

This reverts the tty layer change to use per-tty locking, because it's
not correct yet, and fixing it will require some more deep surgery.

The main revert is d29f3ef39be4 ("tty_lock: Localise the lock"), but
there are several smaller commits that built upon it, they also get
reverted here. The list of reverted commits is:

  fde86d310886 - tty: add lockdep annotations
  8f6576ad476b - tty: fix ldisc lock inversion trace
  d3ca8b64b97e - pty: Fix lock inversion
  b1d679afd766 - tty: drop the pty lock during hangup
  abcefe5fc357 - tty/amiserial: Add missing argument for tty_unlock()
  fd11b42e3598 - cris: fix missing tty arg in wait_event_interruptible_tty call
  d29f3ef39be4 - tty_lock: Localise the lock

The revert had a trivial conflict in the 68360serial.c staging driver
that got removed in the meantime.

Signed-off-by: Linus Torvalds