linux-stable.git/kernel/workqueue.c, branch v3.4.5

workqueue: skip nr_running sanity check in worker_enter_idle() if trustee is active

2012-06-01T07:18:19+00:00

commit 544ecf310f0e7f51fa057ac2a295fc1b3b35a9d3 upstream.

worker_enter_idle() has WARN_ON_ONCE() which triggers if nr_running
isn't zero when every worker is idle.  This can trigger spuriously
while a cpu is going down due to the way trustee sets %WORKER_ROGUE
and zaps nr_running.

It first sets %WORKER_ROGUE on all workers without updating
nr_running, releases gcwq->lock, schedules, regrabs gcwq->lock and
then zaps nr_running.  If the last running worker enters idle
inbetween, it would see stale nr_running which hasn't been zapped yet
and trigger the WARN_ON_ONCE().

Fix it by performing the sanity check iff the trustee is idle.

Signed-off-by: Tejun Heo 
Reported-by: "Paul E. McKenney" 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2012-03-21T01:13:22+00:00

Pull workqueue changes from Tejun Heo:
 "This contains only one commit which cleans up UP allocation path a
  bit."

* 'for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: use percpu allocator for cwq on UP

workqueue: use percpu allocator for cwq on UP

2012-03-12T16:21:17+00:00

I notice that the commit bbddff makes percpu allocator can work on UP,
So we don't need the magic way for UP.

Signed-off-by: Lai Jiangshan 
Signed-off-by: Tejun Heo

Block: use a freezable workqueue for disk-event polling

2012-03-02T09:51:00+00:00

This patch (as1519) fixes a bug in the block layer's disk-events
polling.  The polling is done by a work routine queued on the
system_nrt_wq workqueue.  Since that workqueue isn't freezable, the
polling continues even in the middle of a system sleep transition.

Obviously, polling a suspended drive for media changes and such isn't
a good thing to do; in the case of USB mass-storage devices it can
lead to real problems requiring device resets and even re-enumeration.

The patch fixes things by creating a new system-wide, non-reentrant,
freezable workqueue and using it for disk-events polling.

Signed-off-by: Alan Stern 
CC: 
Acked-by: Tejun Heo 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Jens Axboe

workqueue: make alloc_workqueue() take printf fmt and args for name

2012-01-11T00:30:54+00:00

alloc_workqueue() currently expects the passed in @name pointer to remain
accessible.  This is inconvenient and a bit silly given that the whole wq
is being dynamically allocated.  This patch updates alloc_workqueue() and
friends to take printf format string instead of opaque string and matching
varargs at the end.  The name is allocated together with the wq and
formatted.

alloc_ordered_workqueue() is converted to a macro to unify varargs
handling with alloc_workqueue(), and, while at it, add comment to
alloc_workqueue().

None of the current in-kernel users pass in string with '%' as constant
name and this change shouldn't cause any problem.

[akpm@linux-foundation.org: use __printf]
Signed-off-by: Tejun Heo 
Suggested-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel: Map most files to use export.h instead of module.h

2011-10-31T13:20:12+00:00

The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else.  Revector them
onto the isolated export header for faster compile times.

Nothing to see here but a whole lot of instances of:

  -#include 
  +#include 

This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.

Signed-off-by: Paul Gortmaker

workqueue: lock cwq access in drain_workqueue

2011-09-15T01:09:38+00:00

Take cwq->gcwq->lock to avoid racing between drain_workqueue checking to
make sure the workqueues are empty and cwq_dec_nr_in_flight decrementing
and then incrementing nr_active when it activates a delayed work.

We discovered this when a corner case in one of our drivers resulted in
us trying to destroy a workqueue in which the remaining work would
always requeue itself again in the same workqueue.  We would hit this
race condition and trip the BUG_ON on workqueue.c:3080.

Signed-off-by: Thomas Tuttle 
Acked-by: Tejun Heo 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-3.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2011-07-22T22:07:15+00:00

* 'for-3.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: separate out drain_workqueue() from destroy_workqueue()
  workqueue: remove cancel_rearming_delayed_work[queue]()

Merge branch 'for-2.6.40' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2011-05-24T18:53:42+00:00

* 'for-2.6.40' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: Unify input section names
  percpu: Avoid extra NOP in percpu_cmpxchg16b_double
  percpu: Cast away printk format warning
  percpu: Always align percpu output section to PAGE_SIZE

Fix up fairly trivial conflict in arch/x86/include/asm/percpu.h as per Tejun

workqueue: separate out drain_workqueue() from destroy_workqueue()

2011-05-20T11:54:46+00:00

There are users which want to drain workqueues without destroying it.
Separate out drain functionality from destroy_workqueue() into
drain_workqueue() and make it accessible to workqueue users.

To guarantee forward-progress, only chain queueing is allowed while
drain is in progress.  If a new work item which isn't chained from the
running or pending work items is queued while draining is in progress,
WARN_ON_ONCE() is triggered.

Signed-off-by: Tejun Heo 
Cc: James Bottomley