From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] minimal SAS transport class Date: Sat, 20 Aug 2005 00:57:38 -0400 Message-ID: <4306B842.6010708@pobox.com> References: <9BB4DECD4CFE6D43AA8EA8D768ED51C21D7A40@xbl3.ma.emulex.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.dvmed.net ([216.237.124.58]:5088 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1750748AbVHTE55 (ORCPT ); Sat, 20 Aug 2005 00:57:57 -0400 In-Reply-To: <9BB4DECD4CFE6D43AA8EA8D768ED51C21D7A40@xbl3.ma.emulex.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James.Smart@Emulex.Com Cc: luben_tuikov@adaptec.com, hch@lst.de, jejb@steeleye.com, ltuikov@yahoo.com, Eric.Moore@lsil.com, andrew.patterson@hp.com, linux-scsi@vger.kernel.org James.Smart@Emulex.Com wrote: > For SAS, looking at Christoph's code - > The target id comes from the LLDD. So either the LLDD maintains a > map of SAS port addresses to target ids, or the mapping could change, > same as FC. Christoph's argument is that FC's issue was historical. As James and I discussed on IRC, the FC mapping issue will crop up again, such as with SAS. A core problem is that the SCSI layer expects to address things on a host/channel/id/lun basis, when _that_ addressing is largely a legacy holdover from parallel SCSI. We need to figure out a way to move SCSI layer addressing forward, and eliminate any need for hacks such as FC's mapping. FC's mapping hacks exist because the SCSI layer addressing needs to be made more flexible. Unfortunately, as James also pointed out, changing addressing will cause lots of churn, and potentially some breakage. Jeff