RE: [RFC] staging: unisys: visorbus: visorchipset: Remove create_singlethread_workqueue()

From: Kershner, David A
Date: Sun Feb 28 2016 - 17:06:13 EST


> -----Original Message-----
> From: Amitoj Kaur Chawla [mailto:amitoj1606@xxxxxxxxx]
> Sent: Sunday, February 28, 2016 7:44 AM
> To: Romer, Benjamin M <Benjamin.Romer@xxxxxxxxxx>;
> Jes.Sorensen@xxxxxxxxxx; Arfvidson, Erik <Erik.Arfvidson@xxxxxxxxxx>;
> Kershner, David A <David.Kershner@xxxxxxxxxx>; jkc@xxxxxxxxxx; Sell,
> Timothy C <Timothy.Sell@xxxxxxxxxx>; Thompson, Bryan E.
> <bryan.thompson@xxxxxxxxxx>; dzickus@xxxxxxxxxx;
> kenneth.depro@xxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; *S-Par-
> Maintainer <SParMaintainer@xxxxxxxxxx>; devel@xxxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Cc: tj@xxxxxxxxxx; outreachy-kernel@xxxxxxxxxxxxxxxx
> Subject: [RFC] staging: unisys: visorbus: visorchipset: Remove
> create_singlethread_workqueue()
>
> With concurrency managed workqueues, use of dedicated workqueues
> can be replaced by using system_wq. Drop periodic_controlvm_workqueue
> by using system_wq.
>
> Since there is only one work item periodic_controlvm_work and
> different periodic_controlvm_works do not need to be ordered, increase
> of concurrency level by switching to system_wq should not break anything.
>
> cancel_delayed_work_sync() is used to ensure that work is not pending
> or executing on any CPU.
>
> Signed-off-by: Amitoj Kaur Chawla <amitoj1606@xxxxxxxxx>
> Acked-by: Tejun Heo <tj@xxxxxxxxxx>

Tested on s-Par system, no issues found.

Tested-by: David Kershner <david.kershner@xxxxxxxxxx>

> ---
> Only compile tested.
>
> drivers/staging/unisys/visorbus/visorchipset.c | 23 ++++-------------------
> 1 file changed, 4 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/staging/unisys/visorbus/visorchipset.c
> b/drivers/staging/unisys/visorbus/visorchipset.c
> index b75b063..c4c71c6 100644
> --- a/drivers/staging/unisys/visorbus/visorchipset.c
> +++ b/drivers/staging/unisys/visorbus/visorchipset.c
> @@ -102,7 +102,6 @@ struct parser_context {
> };
>
> static struct delayed_work periodic_controlvm_work;
> -static struct workqueue_struct *periodic_controlvm_workqueue;
> static DEFINE_SEMAPHORE(notifier_lock);
>
> static struct cdev file_cdev;
> @@ -1913,8 +1912,7 @@ cleanup:
> poll_jiffies =
> POLLJIFFIES_CONTROLVMCHANNEL_FAST;
> }
>
> - queue_delayed_work(periodic_controlvm_workqueue,
> - &periodic_controlvm_work, poll_jiffies);
> + schedule_delayed_work(&periodic_controlvm_work, poll_jiffies);
> }
>
> static void
> @@ -2011,8 +2009,7 @@ cleanup:
>
> poll_jiffies = POLLJIFFIES_CONTROLVMCHANNEL_SLOW;
>
> - queue_delayed_work(periodic_controlvm_workqueue,
> - &periodic_controlvm_work, poll_jiffies);
> + schedule_delayed_work(&periodic_controlvm_work, poll_jiffies);
> }
>
> static void
> @@ -2299,19 +2296,10 @@ visorchipset_init(struct acpi_device
> *acpi_device)
> else
> INIT_DELAYED_WORK(&periodic_controlvm_work,
> controlvm_periodic_work);
> - periodic_controlvm_workqueue =
> - create_singlethread_workqueue("visorchipset_controlvm");
>
> - if (!periodic_controlvm_workqueue) {
> - POSTCODE_LINUX_2(CREATE_WORKQUEUE_FAILED_PC,
> - DIAG_SEVERITY_ERR);
> - rc = -ENOMEM;
> - goto cleanup;
> - }
> most_recent_message_jiffies = jiffies;
> poll_jiffies = POLLJIFFIES_CONTROLVMCHANNEL_FAST;
> - queue_delayed_work(periodic_controlvm_workqueue,
> - &periodic_controlvm_work, poll_jiffies);
> + schedule_delayed_work(&periodic_controlvm_work, poll_jiffies);
>
> visorchipset_platform_device.dev.devt = major_dev;
> if (platform_device_register(&visorchipset_platform_device) < 0) {
> @@ -2346,10 +2334,7 @@ visorchipset_exit(struct acpi_device *acpi_device)
>
> visorbus_exit();
>
> - cancel_delayed_work(&periodic_controlvm_work);
> - flush_workqueue(periodic_controlvm_workqueue);
> - destroy_workqueue(periodic_controlvm_workqueue);
> - periodic_controlvm_workqueue = NULL;
> + cancel_delayed_work_sync(&periodic_controlvm_work);
> destroy_controlvm_payload_info(&controlvm_payload_info);
>
> memset(&g_chipset_msg_hdr, 0, sizeof(struct
> controlvm_message_header));
> --
> 1.9.1