[media] gspca: finepix: Remove deprecated create_singlethread_workqueue
authorBhaktipriya Shridhar <bhaktipriya96@gmail.com>
Sat, 16 Jul 2016 08:55:56 +0000 (05:55 -0300)
committerMauro Carvalho Chehab <mchehab@s-opensource.com>
Wed, 24 Aug 2016 12:30:21 +0000 (09:30 -0300)
commit53eebd84c3ac2a81da94535594dba6ff637311dd
tree9fb9da06aff94efe243344aebac11d319bdad7a4
parente59646895778f1e645b4e2f02d99aaec7a144ce1
[media] gspca: finepix: Remove deprecated create_singlethread_workqueue

The workqueue "work_thread" is involved in streaming the camera data.
It has a single work item(&dev->work_struct) and hence doesn't require
ordering. Also, it is not being used on a memory reclaim path.
Hence, the singlethreaded workqueue has been replaced with the use of
system_wq.

System workqueues have been able to handle high level of concurrency
for a long time now and hence it's not required to have a singlethreaded
workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
created with create_singlethread_workqueue(), system_wq allows multiple
work items to overlap executions even on the same CPU; however, a
per-cpu workqueue doesn't have any CPU locality or global ordering
guarantee unless the target CPU is explicitly specified and thus the
increase of local concurrency shouldn't make any difference.

Work item has been flushed in sd_stop0() to ensure that there are no
pending tasks while disconnecting the driver.

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Frank Zago <frank@zago.net>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
drivers/media/usb/gspca/finepix.c