Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993173AbXEBWKf (ORCPT ); Wed, 2 May 2007 18:10:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2993188AbXEBWKf (ORCPT ); Wed, 2 May 2007 18:10:35 -0400 Received: from einhorn.in-berlin.de ([192.109.42.8]:45095 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993173AbXEBWKe (ORCPT ); Wed, 2 May 2007 18:10:34 -0400 X-Envelope-From: stefanr@s5r6.in-berlin.de Message-ID: <46390C3F.9060905@s5r6.in-berlin.de> Date: Thu, 03 May 2007 00:10:07 +0200 From: Stefan Richter User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.2) Gecko/20070408 SeaMonkey/1.1.1 MIME-Version: 1.0 To: Christoph Hellwig , Stefan Richter , linux-kernel@vger.kernel.org, Kristian H??gsberg , Linus Torvalds , Andrew Morton , linux1394-devel Subject: Re: [PATCH 5/6] firewire: SBP-2 highlevel driver References: <4637A29F.6070302@redhat.com> <20070502090007.GA28174@infradead.org> <20070502194408.GD1248@infradead.org> <4639085A.8010504@s5r6.in-berlin.de> In-Reply-To: <4639085A.8010504@s5r6.in-berlin.de> X-Enigmail-Version: 0.94.1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1423 Lines: 33 I wrote: > Christoph Hellwig wrote: >>> + /* Convert the scatterlist to an sbp2 page table. If any >>> + * scatterlist entries are too big for sbp2 we split the as we go. */ >> Please set the max_sectors value in your host template so that the >> block layer doesn't build sg entries too big for you. > > Hmm, what about this: > > James Bottomley wrote on 2007-01-15: > | Actually, there's one unfortunate case where Linux won't respect this: > | an IOMMU that can do virtual merging. This parameter is a block queue > | parameter, so block will happily make sure the request segments obey it. > | However, when you get to dma_map_rq() it doesn't see the segment limits, > | so, if the iommu merges, you can end up with SG elements the other side > | that violate this. I've been meaning to do something about this for > | ages (IDE is the other subsystem that has an absolute requirement for a > | fixed maximum segment size) but never found an excuse to fix it. > > http://marc.info/?l=linux-scsi&m=116889641203397 PS: Nonetheless, yes, fw-sbp2.c is curiously missing to set the template's max_sectors. -- Stefan Richter -=====-=-=== -=-= ---== http://arcgraph.de/sr/ - 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/