RE: [RFC] staging: unisys: visornic: Remove create_singlethread_workqueue()

From: Kershner, David A
Date: Sun Feb 28 2016 - 17:07:18 EST


> -----Original Message-----
> From: Amitoj Kaur Chawla [mailto:amitoj1606@xxxxxxxxx]
> Sent: Sunday, February 28, 2016 7:57 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;
> gregkh@xxxxxxxxxxxxxxxxxxx; *S-Par-Maintainer
> <SParMaintainer@xxxxxxxxxx>; devel@xxxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: tj@xxxxxxxxxx; outreachy-kernel@xxxxxxxxxxxxxxxx
> Subject: [RFC] staging: unisys: visornic: Remove
> create_singlethread_workqueue()
>
> With concurrency managed workqueues, use of dedicated workqueues
> can be replaced by using system_wq.
> Drop visornic_timeout_reset_workqueue by using system_wq.
>
> Since there is only one work item per devdata and different
> devdatas do not need to be ordered, increase of concurrency
> level by switching to system_wq should not break anything.
>
> cancel_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/visornic/visornic_main.c | 21 ++-------------------
> 1 file changed, 2 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/staging/unisys/visornic/visornic_main.c
> b/drivers/staging/unisys/visornic/visornic_main.c
> index df4f688..6749c4e 100644
> --- a/drivers/staging/unisys/visornic/visornic_main.c
> +++ b/drivers/staging/unisys/visornic/visornic_main.c
> @@ -59,8 +59,6 @@ static const struct file_operations
> debugfs_enable_ints_fops = {
> .write = enable_ints_write,
> };
>
> -static struct workqueue_struct *visornic_timeout_reset_workqueue;
> -
> /* GUIDS for director channel type supported by this driver. */
> static struct visor_channeltype_descriptor visornic_channel_types[] = {
> /* Note that the only channel type we expect to be reported by the
> @@ -1070,7 +1068,7 @@ visornic_xmit_timeout(struct net_device *netdev)
> spin_unlock_irqrestore(&devdata->priv_lock, flags);
> return;
> }
> - queue_work(visornic_timeout_reset_workqueue, &devdata-
> >timeout_reset);
> + schedule_work(&devdata->timeout_reset);
> spin_unlock_irqrestore(&devdata->priv_lock, flags);
> }
>
> @@ -1998,7 +1996,7 @@ static void visornic_remove(struct visor_device
> *dev)
> }
>
> /* going_away prevents new items being added to the workqueues
> */
> - flush_workqueue(visornic_timeout_reset_workqueue);
> + cancel_work_sync(&devdata->timeout_reset);
>
> debugfs_remove_recursive(devdata->eth_debugfs_dir);
>
> @@ -2117,21 +2115,10 @@ static int visornic_init(void)
> if (!ret)
> goto cleanup_debugfs;
>
> - /* create workqueue for tx timeout reset */
> - visornic_timeout_reset_workqueue =
> - create_singlethread_workqueue("visornic_timeout_reset");
> - if (!visornic_timeout_reset_workqueue)
> - goto cleanup_workqueue;
> -
> err = visorbus_register_visor_driver(&visornic_driver);
> if (!err)
> return 0;
>
> -cleanup_workqueue:
> - if (visornic_timeout_reset_workqueue) {
> - flush_workqueue(visornic_timeout_reset_workqueue);
> - destroy_workqueue(visornic_timeout_reset_workqueue);
> - }
> cleanup_debugfs:
> debugfs_remove_recursive(visornic_debugfs_dir);
>
> @@ -2147,10 +2134,6 @@ static void visornic_cleanup(void)
> {
> visorbus_unregister_visor_driver(&visornic_driver);
>
> - if (visornic_timeout_reset_workqueue) {
> - flush_workqueue(visornic_timeout_reset_workqueue);
> - destroy_workqueue(visornic_timeout_reset_workqueue);
> - }
> debugfs_remove_recursive(visornic_debugfs_dir);
> }
>
> --
> 1.9.1