Re: [PATCH 2/3] Input: touchscreen: mc13783_ts: Remove deprecated create_singletheread_workqueue

From: Dmitry Torokhov
Date: Tue Aug 23 2016 - 16:53:20 EST


On Sun, Aug 14, 2016 at 10:55:30AM +0530, Bhaktipriya Shridhar wrote:
> The workqueue "workqueue" has a single workitem(&priv->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.
>
> Workitem is sync cancelled in mc13783_ts_remove() to ensure that there
> are no workitems pending when the driver is disconnected.
>
> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@xxxxxxxxx>

Applied, thank you. But:

> @@ -233,7 +222,7 @@ static int mc13783_ts_remove(struct platform_device *pdev)
> {
> struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
>
> - destroy_workqueue(priv->workq);
> + cancel_delayed_work_sync(&priv->work);

This is not needed, we cancel work in mc13783_ts_close(). I dropped this
bit.

> input_unregister_device(priv->idev);
> kfree(priv);
>
> --
> 2.1.4
>

--
Dmitry