From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752284AbbLVHKu (ORCPT ); Tue, 22 Dec 2015 02:10:50 -0500 Received: from mx2.suse.de ([195.135.220.15]:42122 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750729AbbLVHKs (ORCPT ); Tue, 22 Dec 2015 02:10:48 -0500 Subject: Re: [PATCH v3 20/77] ncr5380: Introduce unbound workqueue To: Finn Thain , "James E.J. Bottomley" , Michael Schmitz , linux-m68k@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, "Martin K. Petersen" , Russell King , linux-arm-kernel@lists.infradead.org References: <20151222011737.980475848@telegraphics.com.au> <20151222011743.455500361@telegraphics.com.au> From: Hannes Reinecke Message-ID: <5678F776.8080305@suse.de> Date: Tue, 22 Dec 2015 08:10:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <20151222011743.455500361@telegraphics.com.au> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/22/2015 02:17 AM, Finn Thain wrote: > Allocate a work queue that will permit busy waiting and sleeping. This > means NCR5380_init() can potentially fail, so add this error path. > > Signed-off-by: Finn Thain > > --- > > In subsequent patches, the work function adopts this work queue so it > can sleep while polling, which allows the removal of some flawed and > complicated code in NCR5380_select() in NCR5380.c. > > Changed since v1: > - Dropped WQ_CPU_INTENSIVE flag because Documentation/workqueue.txt says it > "is meaningless for unbound wq". > > --- > drivers/scsi/NCR5380.c | 15 +++++++++++---- > drivers/scsi/NCR5380.h | 1 + > drivers/scsi/arm/cumana_1.c | 8 ++++++-- > drivers/scsi/arm/oak.c | 8 ++++++-- > drivers/scsi/atari_NCR5380.c | 8 +++++++- > drivers/scsi/atari_scsi.c | 5 ++++- > drivers/scsi/dmx3191d.c | 17 +++++++++++------ > drivers/scsi/dtc.c | 11 +++++++++-- > drivers/scsi/g_NCR5380.c | 31 +++++++++++++++---------------- > drivers/scsi/mac_scsi.c | 5 ++++- > drivers/scsi/pas16.c | 10 ++++++++-- > drivers/scsi/sun3_scsi.c | 5 ++++- > drivers/scsi/t128.c | 13 ++++++++++--- > 13 files changed, 96 insertions(+), 41 deletions(-) > > Index: linux/drivers/scsi/NCR5380.c > =================================================================== > --- linux.orig/drivers/scsi/NCR5380.c 2015-12-22 12:15:52.000000000 +1100 > +++ linux/drivers/scsi/NCR5380.c 2015-12-22 12:15:56.000000000 +1100 > @@ -514,7 +514,7 @@ static int should_disconnect(unsigned ch > static void NCR5380_set_timer(struct NCR5380_hostdata *hostdata, unsigned long timeout) > { > hostdata->time_expires = jiffies + timeout; > - schedule_delayed_work(&hostdata->coroutine, timeout); > + queue_delayed_work(hostdata->work_q, &hostdata->coroutine, timeout); > } > > > @@ -791,7 +791,12 @@ static int NCR5380_init(struct Scsi_Host > hostdata->disconnected_queue = NULL; > > INIT_DELAYED_WORK(&hostdata->coroutine, NCR5380_main); > - > + hostdata->work_q = alloc_workqueue("ncr5380_%d", > + WQ_UNBOUND | WQ_MEM_RECLAIM, > + 1, instance->host_no); > + if (!hostdata->work_q) > + return -ENOMEM; > + > /* The CHECK code seems to break the 53C400. Will check it later maybe */ > if (flags & FLAG_NCR53C400) > hostdata->flags = FLAG_HAS_LAST_BYTE_SENT | flags; Wouldn't it be better to use a normal (ie bound) workqueue here? SCSI-2 is pretty much single-threaded, so shifting things onto arbitrary CPUs don't sound very appealing. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)