From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erez Zilber Subject: Re: [PATCH 1/3 v2] iscsi iser: remove DMA alignment restriction Date: Mon, 05 May 2008 16:19:02 +0300 Message-ID: <481F0946.4020505@Voltaire.COM> References: <20080214211029.GA21073@osc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from fwil.voltaire.com ([193.47.165.2]:43341 "EHLO exil.voltaire.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754973AbYEENST (ORCPT ); Mon, 5 May 2008 09:18:19 -0400 In-Reply-To: <20080214211029.GA21073@osc.edu> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Pete Wyckoff Cc: Mike Christie , Roland Dreier , James Bottomley , linux-scsi Pete Wyckoff wrote: > Thanks to James pointing out the problems with the BLK_BOUNCE_ANY > for IB devices, this revised patch contains only the DMA alignment > fix for iSER. > > Mike, can you take care of this and the other two patches in the > series: > > [PATCH 2/3] iscsi iser: increase max_sectors > [PATCH 3/3] iscsi iser: increase sg_tablesize > > -- Pete > > > From 255e73b67ec1458af18395981fddebdc958e8fe9 Mon Sep 17 00:00:00 2001 > From: Pete Wyckoff > Date: Thu, 14 Feb 2008 16:09:27 -0500 > Subject: [PATCH] iscsi iser: remove DMA alignment restriction > > iscsi_iser does not require any particular DMA aligement > requirement. Add a slave_configure function to set the alignment > to zero, allowing the use of direct IO from arbitrary offsets > within a page. > We had a long discussion about it, and I'm ok with this patch. However, I would change the description: iSER has DMA alignment requirements that are too complex to express with q->dma_alignment. Therefore, if necessary, bouncing should be done by the iSER driver. Add a slave_configure function to set the alignment to zero, allowing the use of direct IO from arbitrary offsets within a page. Erez