From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] SCSI Core patches Date: Sat, 11 Jan 2003 18:12:24 +0000 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20030111181224.B3178@infradead.org> References: <3E1ADC9A.6090800@splentec.com> <20030107102127.B15528@beaverton.ibm.com> <3E1B2934.8060805@splentec.com> <20030107123301.A16378@beaverton.ibm.com> <3E1B513B.2090409@splentec.com> <20030107173633.A17825@beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20030107173633.A17825@beaverton.ibm.com>; from patmans@us.ibm.com on Tue, Jan 07, 2003 at 05:36:33PM -0800 List-Id: linux-scsi@vger.kernel.org To: Patrick Mansfield Cc: Luben Tuikov , linux-scsi@vger.kernel.org On Tue, Jan 07, 2003 at 05:36:33PM -0800, Patrick Mansfield wrote: > Having the LLDD use more data structures does not imply a better > abstraction. Again, a better abstraction would be to use interfaces to > get the host/channel/target/lun. This could add overhead depending on the > implementation. Not having the cmnd replicate information in the device implies a better abstraction :) The LLDD knows about struct scsi_device anyway. > > For this reason you might consider the suggestions by Doug, or research moving > > multipathing higher up into the char/block layer, or thereabouts. > > I have looked into putting multipath in the block layer, I've looked at > md, at the T3 code, and at the qlogic multi-path code. Code in the block > layer would be interesting, but might not solve problems with char > devices, Scsi character drivers _do_ go through the block layer. (through scsi_do_req).