linux-kernel - RE: [RFC] staging: unisys: visorbus: visorchipset: Remove create_singlethread

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4fc014dcc3dd496590e10920a9389aec@US-EXCH13-1.na.uis.unisys.com>
Date:	Sun, 28 Feb 2016 21:59:46 +0000
From:	"Kershner, David A" <David.Kershner@...sys.com>
To:	Amitoj Kaur Chawla <amitoj1606@...il.com>,
	"Jes.Sorensen@...hat.com" <Jes.Sorensen@...hat.com>,
	"Arfvidson, Erik" <Erik.Arfvidson@...sys.com>,
	"jkc@...hat.com" <jkc@...hat.com>,
	"Sell, Timothy C" <Timothy.Sell@...sys.com>,
	"Thompson, Bryan E." <bryan.thompson@...sys.com>,
	"dzickus@...hat.com" <dzickus@...hat.com>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	*S-Par-Maintainer <SParMaintainer@...sys.com>,
	"devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	"tj@...nel.org" <tj@...nel.org>,
	"outreachy-kernel@...glegroups.com" 
	<outreachy-kernel@...glegroups.com>
Subject: RE: [RFC] staging: unisys: visorbus: visorchipset: Remove
 create_singlethread_workqueue()

> -----Original Message-----
> From: Amitoj Kaur Chawla [mailto:amitoj1606@...il.com]
> Sent: Sunday, February 28, 2016 7:44 AM
> To: Romer, Benjamin M <Benjamin.Romer@...sys.com>;
> Jes.Sorensen@...hat.com; Arfvidson, Erik <Erik.Arfvidson@...sys.com>;
> Kershner, David A <David.Kershner@...sys.com>; jkc@...hat.com; Sell,
> Timothy C <Timothy.Sell@...sys.com>; Thompson, Bryan E.
> <bryan.thompson@...sys.com>; dzickus@...hat.com;
> kenneth.depro@...sys.com; gregkh@...uxfoundation.org; *S-Par-
> Maintainer <SParMaintainer@...sys.com>; devel@...verdev.osuosl.org;
> linux-kernel@...r.kernel.org
> Cc: tj@...nel.org; outreachy-kernel@...glegroups.com
> 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@...il.com>
> Acked-by: Tejun Heo <tj@...nel.org>

Tested on s-Par system, no issues found. 

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

> ---
> 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