From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Date: Tue, 02 Mar 2010 13:38:31 +0000 Subject: Re: [PATCH] sparc: use asm-generic/scatterlist.h Message-Id: <201003021438.32144.arnd@arndb.de> List-Id: References: <201003011229.51399.arnd@arndb.de> <201003021303.26064.arnd@arndb.de> <20100302212513N.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20100302212513N.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: FUJITA Tomonori Cc: davem@davemloft.net, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org On Tuesday 02 March 2010, FUJITA Tomonori wrote: > Yeah, but IIRC, Alpha, x86_64 GART, parisc, and IA64 don't have > CONFIG_ option for IOMMU virtual merging. I prefer to avoid to adding > something like CONFIG_HAVE_IOMMU_VMERGE for them. If we add > CONFIG_HAVE_IOMMU_VMERGE to them, it's a bit strange not to add the > feature to disable virtual merging for them (I guess GART already has > the feature though). While I think the runtime feature (actually a workaround for broken device drivers) should be consistently used on all architectures, or removed entirely, it's orthogonal to this discussion. I'm sure you'll come up with a reasonable name for a new option if you introduce one. CONFIG_HAVE_IOMMU_VMERGE and CONFIG_NEED_SG_DMA_LENGTH both seem ok to me. > Actually, I want to use dma_length on all the architectures (if nobody > complains). Fine with me as well. It wastes a small amount of memory but makes the code more consistent. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753188Ab0CBNik (ORCPT ); Tue, 2 Mar 2010 08:38:40 -0500 Received: from moutng.kundenserver.de ([212.227.17.8]:63135 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752946Ab0CBNii (ORCPT ); Tue, 2 Mar 2010 08:38:38 -0500 From: Arnd Bergmann To: FUJITA Tomonori Subject: Re: [PATCH] sparc: use asm-generic/scatterlist.h Date: Tue, 2 Mar 2010 14:38:31 +0100 User-Agent: KMail/1.12.2 (Linux/2.6.31-14-generic; KDE/4.3.2; x86_64; ; ) Cc: davem@davemloft.net, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org References: <201003011229.51399.arnd@arndb.de> <201003021303.26064.arnd@arndb.de> <20100302212513N.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20100302212513N.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201003021438.32144.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX18kIF0ZEO+OLn0i4SscGXFQU58B4O+bTx7R0Fb PedTc4SLHRjiHopi5iC56Jr/cx0dYPfS212qL9x349lcKA0bz/ mmpwgy1gnTBam5ocPUBMA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 02 March 2010, FUJITA Tomonori wrote: > Yeah, but IIRC, Alpha, x86_64 GART, parisc, and IA64 don't have > CONFIG_ option for IOMMU virtual merging. I prefer to avoid to adding > something like CONFIG_HAVE_IOMMU_VMERGE for them. If we add > CONFIG_HAVE_IOMMU_VMERGE to them, it's a bit strange not to add the > feature to disable virtual merging for them (I guess GART already has > the feature though). While I think the runtime feature (actually a workaround for broken device drivers) should be consistently used on all architectures, or removed entirely, it's orthogonal to this discussion. I'm sure you'll come up with a reasonable name for a new option if you introduce one. CONFIG_HAVE_IOMMU_VMERGE and CONFIG_NEED_SG_DMA_LENGTH both seem ok to me. > Actually, I want to use dma_length on all the architectures (if nobody > complains). Fine with me as well. It wastes a small amount of memory but makes the code more consistent. Arnd