Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262663AbVDYQY7 (ORCPT ); Mon, 25 Apr 2005 12:24:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262654AbVDYQXS (ORCPT ); Mon, 25 Apr 2005 12:23:18 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:36766 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S262669AbVDYQOY (ORCPT ); Mon, 25 Apr 2005 12:14:24 -0400 Date: Mon, 25 Apr 2005 17:14:11 +0100 From: Christoph Hellwig To: Luben Tuikov Cc: SCSI Mailing List , Linux Kernel Mailing List , andrew.patterson@hp.com, Eric.Moore@lsil.com, mike.miller@hp.com, dougg@torque.net, Madhuresh_Nagshain@adaptec.com Subject: Re: [RFC] SAS domain layout for Linux sysfs Message-ID: <20050425161411.GA11938@infradead.org> Mail-Followup-To: Christoph Hellwig , Luben Tuikov , SCSI Mailing List , Linux Kernel Mailing List , andrew.patterson@hp.com, Eric.Moore@lsil.com, mike.miller@hp.com, dougg@torque.net, Madhuresh_Nagshain@adaptec.com References: <425D392F.2080702@adaptec.com> <20050424111908.GA23010@infradead.org> <426D1572.70508@adaptec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <426D1572.70508@adaptec.com> User-Agent: Mutt/1.4.1i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1823 Lines: 45 On Mon, Apr 25, 2005 at 12:06:10PM -0400, Luben Tuikov wrote: > On 04/24/05 07:19, Christoph Hellwig wrote: > > > > This is contrary to any sysfs topology I know about, especially any > > existing transport class (SPI, FC, iSCSI). > > This RFC is about SAS. But our SAS transport class should be consistant with the other transport classes. > > We only ever care about what's seen from a HA, > > Imagine you could connect to the same device via two > different PCI controllers on the same host. Which is exactly the case in the examples I've mentioned. > > > e.g. if you have muliple SPI cards that are > > on a single parallel bus you'll have the same bus represented twice, > > similarly if you have two fibre channel HBAs connected to the same > > SAN you'll have the SAN topology duplicated in both sub-topologies. > > Hmm, this proposal is for SAS only, Christoph. > > If you have multiple SAS host adapters connected to the same > SAS domain, the _path_ they connect to a SAS device may be _different_. > But what is the same is the SAS domain (topology) itself *regardless of > how you connect to it.* > > In order to eliminate duplication of sysfs entries (directories > and files) to describe the same SAS device, we split up the > representation into a "flat" directory with just a bunch > of SAS devices, this is /sys/bus/sas/. And the way you _connect_ > to those SAS devices is represented in sys/class/sas_ha/. Please read the previous mail again, you're not getting it at all. If you don't understand the problems it's not worth talking about more. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/