From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [PATCH] tmscsim: INQUIRY always only untagged Date: Wed, 15 Sep 2004 15:30:24 +1000 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <4147D370.3040003@torque.net> References: <20040904140102.A15247@infradead.org> <20040904233835.A18659@infradead.org> <1094398979.10977.9.camel@mulgrave> <20040905173134.A31521@infradead.org> <1094422949.10977.15.camel@mulgrave> Reply-To: dougg@torque.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from borg.st.net.au ([65.23.158.22]:9956 "EHLO borg.st.net.au") by vger.kernel.org with ESMTP id S267625AbUIOFbQ (ORCPT ); Wed, 15 Sep 2004 01:31:16 -0400 In-Reply-To: <1094422949.10977.15.camel@mulgrave> List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Christoph Hellwig , Guennadi Liakhovetski , SCSI Mailing List James Bottomley wrote: > On Sun, 2004-09-05 at 12:31, Christoph Hellwig wrote: > >>Umm yes. But lets get the driver no oops first and then move forward. >>There's still a lot of work to do on the driver. > > > Well, OK. I agree to putting a palliative fix in, since what I > suggested will probably take more thought, but I don't think this one is > actually it. Mixing tagged and untagged commands is illegal under the > SCSI spec. Simply untagging the INQUIRY command may work to fix this > particular bug, but I bet it will introduce others when a scsi utility > sends an INQUIRY down to an in-use device. Seems as though INQUIRY, REPORT LUNS and READ CAPACITY are special in this respect since the task manager may (i.e. should) treat them as implicit Head Of Queue. This proposal: http://www.t10.org/ftp/t10/document.04/04-310r1.pdf advises application clients not to send the "specials" with ORDERED (i.e. tagged) task attribute. My guess is that if any data that those "specials" monitor is changed they will hit the next command status with an advisory sense_key/asc/ascq sense. Then the application client should send one of those "specials" out asap to find out what changed (and not be held up by task manager). Doug Gilbert