[media] gspca: sonixj: Remove deprecated create_singlethread_workqueue
authorBhaktipriya Shridhar <bhaktipriya96@gmail.com>
Sat, 16 Jul 2016 08:50:28 +0000 (05:50 -0300)
committerMauro Carvalho Chehab <mchehab@s-opensource.com>
Wed, 24 Aug 2016 12:29:09 +0000 (09:29 -0300)
commitc994be4a7c8471b950ed9baf4558ff488b127ec8
tree2f272057b79a10250c40e989c64befecd497387f
parent29a3006e5209b5dde2d370b8de1e8c18c14040e7
[media] gspca: sonixj: Remove deprecated create_singlethread_workqueue

The workqueue "work_thread" is involved in updating the JPEG quality
of the gspca_dev. It has a single work item(&sd->work) 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>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
drivers/media/usb/gspca/sonixj.c