From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Richter Subject: Re: Proposals to change the way all drivers work with SCSI commands Date: Fri, 11 May 2007 23:20:31 +0200 Message-ID: <4644DE1F.8050107@s5r6.in-berlin.de> References: <1178908422.3692.58.camel@mulgrave.il.steeleye.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from einhorn.in-berlin.de ([192.109.42.8]:38492 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759463AbXEKVUl (ORCPT ); Fri, 11 May 2007 17:20:41 -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 Cc: linux-scsi , =?ISO-8859-1?Q?Kristian_H=F8?= =?ISO-8859-1?Q?gsberg?= James Bottomley wrote: > 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) Should be fine with the old and the new SBP-2 driver. > 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? The old SBP-2 driver needs the virtual addresses of S/G elements if compiled with a certain config option. This option is meant for use with FireWire controllers which do not implement OHCI-1394, or to run the IEEE 1394 stack in a more secure mode. However, sbp2 seems to be broken in multiple ways with this option at the moment, and I don't plan to fix it anytime soon. So in short, moving the DMA mapping into mid layer should also be fine with the old and the new SBP-2 driver. -- Stefan Richter -=====-=-=== -=-= -=-== http://arcgraph.de/sr/