From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: aic7xxx sets CDR offline, how to reset? Date: Tue, 03 Sep 2002 14:09:44 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <200209031909.g83J9iG07312@localhost.localdomain> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: (from root@localhost) by pogo.mtv1.steeleye.com (8.9.3/8.9.3) id MAA20210 for ; Tue, 3 Sep 2002 12:09:58 -0700 In-Reply-To: Message from Doug Ledford of "Tue, 03 Sep 2002 14:23:53 EDT." <20020903142353.A12157@redhat.com> List-Id: linux-scsi@vger.kernel.org To: James Bottomley , "Justin T. Gibbs" , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org dledford@redhat.com said: > Leave abort active. It does actually work in certain scenarios. The > CD burner scenario that started this thread is an example of > somewhere that an abort should actually do the job. Unfortunately, it would destroy the REQ_BARRIER approach in the block layer. At best, abort probably causes a command to overtake a barrier it shouldn't, at worst we abort the ordered tag that is the barrier and transactional integrity is lost. When error correction is needed, we have to return all the commands for that device to the block layer so that ordering and barrier issues can be taken care of in the reissue. This makes LUN RESET (for those that support it) the minimum level of error correction we can apply. James