From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH + RFC] Beginning of some updates to scsi mid layer Date: Fri, 28 Jun 2002 03:37:04 -0400 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20020628033704.B23044@redhat.com> References: <20020619014048.B8623@redhat.com> <20020619134436.A27002@devserv.devel.redhat.com> <20020619142554.G8854@redhat.com> <10206272241.ZM1032399@classic.engr.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <10206272241.ZM1032399@classic.engr.sgi.com>; from jeremy@classic.engr.sgi.com on Thu, Jun 27, 2002 at 10:41:31PM -0700 List-Id: linux-scsi@vger.kernel.org To: Jeremy Higdon Cc: Pete Zaitcev , linux-scsi@vger.kernel.org On Thu, Jun 27, 2002 at 10:41:31PM -0700, Jeremy Higdon wrote: > Is there any accounting for the following condition: > > An array with multiple logical units can accept 256 commands (for > argument purposes) from all initiators for all luns. Therefore, > the number of commands that you can queue to sdX is dependent > on how many commands queued by this initiator to other sds, as well > as how many commands other initiators have issued to this sd and > others. That's (currently) on a per driver basis. My driver would account for this situation just fine. Others might not. That is one of the things I plan to change in the mid layer very soon now. > This may not be an issue so much with parallel SCSI RAIDs, but it does > come up with Fibrechannel. > > It is theoretically possible to get QUEUE_FULL when the host has no other > commands in progress on a logical unit. Would the host driver then believe > that it could issue 0 or 1 command only, or is there some lower limit? > > jeremy -- Doug Ledford 919-754-3700 x44233 Red Hat, Inc. 1801 Varsity Dr. Raleigh, NC 27606