From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: Proposals to change the way all drivers work with SCSI commands Date: Fri, 11 May 2007 13:00:24 -0700 (PDT) Message-ID: <20070511.130024.104034874.davem@davemloft.net> References: <1178908422.3692.58.camel@mulgrave.il.steeleye.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:45417 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1759351AbXEKUAT (ORCPT ); Fri, 11 May 2007 16:00:19 -0400 In-Reply-To: <1178908422.3692.58.camel@mulgrave.il.steeleye.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James.Bottomley@SteelEye.com Cc: linux-scsi@vger.kernel.org From: James Bottomley Date: Fri, 11 May 2007 13:33:41 -0500 > Right at the moment, we're planning to clean up the way SCSI drivers > process commands. The proposals are essentially: > > 1. Get rid of the now unnecessary map_single path (every command is > either zero transfer or scatter/gather) > 2. use accessors to manipulate the SG lists (mainly so that we can > alter the implementation without affecting the drivers) > > It strikes me that in all of this, we could also consider doing the DMA > mapping inside the mid layer (instead of in every driver). This is > essentially what libata is already doing ... leading to confusion in > SCSI drivers that use libata for SATA. > > So what do people think about this? This would require platforms to handle all of their bus types behind the generic dma_*() and that's isn't true everywhere yet. For example, SBUS still requires explicitly using sbus_map_sg() etc. I plan to fix that of course, but we're not there now.