From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH] QStor SATA/RAID driver for 2.6.9-rc3 Date: Fri, 08 Oct 2004 11:38:54 -0400 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <4166B48E.3020006@rtr.ca> References: <4161A06D.8010601@rtr.ca> <416547B6.5080505@rtr.ca> <20041007150709.B12688@infradead.org> <4165624C.5060405@rtr.ca> <416565DB.4050006@pobox.com> <4165A45D.2090200@rtr.ca> <4165A766.1040104@pobox.com> <4165A85D.7080704@rtr.ca> <4165AB1B.8000204@pobox.com> <4165ACF8.8060208@rtr.ca> <20041007221537.A17712@infradead.org> <1097241583.2412.15.camel@mulgrave> <4166AF2F.6070904@rtr.ca> <1097249266.1678.40.camel@mulgrave> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from cpu1185.adsl.bellglobal.com ([207.236.110.166]:63166 "EHLO mail.rtr.ca") by vger.kernel.org with ESMTP id S270040AbUJHPkp (ORCPT ); Fri, 8 Oct 2004 11:40:45 -0400 In-Reply-To: <1097249266.1678.40.camel@mulgrave> List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Christoph Hellwig , Jeff Garzik , Mark Lord , Linux Kernel , SCSI Mailing List James Bottomley wrote: > On Fri, 2004-10-08 at 10:15, Mark Lord wrote: > >>>Actually, the driver has no need for a thread at all. Since you're >>>simply using it to fire hotplug events, use schedule_work instead. >> >>That worries me some, because the mid-layer will perform blocking I/O >>and the like, and I'm not sure how much that stuff may depend on its >>own usage (any?) of workqueues. If you believe it to be safe, >>then I'll nuke the kthread entirely. > > > We use this already for other entities that require user context like > domain validation. It seems to work as advertised. Can deadlock occur here, since qstor.c is already using schedule_work() as part of it's internal bottom-half handling for abnormal conditions? Eg. hotplug event -> schedule_work -> mid-layer -> queuecommand --> sleep :: interrupt -> schedule_work -> deadlock? Just checking.. we all want this to function well. -- Mark Lord (hdparm keeper & the original "Linux IDE Guy")