From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756069AbZDHXCU (ORCPT ); Wed, 8 Apr 2009 19:02:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755848AbZDHXBp (ORCPT ); Wed, 8 Apr 2009 19:01:45 -0400 Received: from sh.osrg.net ([192.16.179.4]:41584 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755885AbZDHXBo (ORCPT ); Wed, 8 Apr 2009 19:01:44 -0400 Date: Thu, 9 Apr 2009 08:01:18 +0900 To: jeremy@goop.org Cc: fujita.tomonori@lab.ntt.co.jp, galak@kernel.crashing.org, hch@infradead.org, linux-kernel@vger.kernel.org, mingo@elte.hu, ian.campbell@citrix.com, beckyb@kernel.crashing.org Subject: Re: [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping From: FUJITA Tomonori In-Reply-To: <49DD270A.6060506@goop.org> References: <49DD1D6B.6030001@goop.org> <20090409071032M.fujita.tomonori@lab.ntt.co.jp> <49DD270A.6060506@goop.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20090409080143C.fujita.tomonori@lab.ntt.co.jp> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (sh.osrg.net [192.16.179.4]); Thu, 09 Apr 2009 08:01:19 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 08 Apr 2009 15:36:58 -0700 Jeremy Fitzhardinge wrote: > FUJITA Tomonori wrote: > >> Some architectures need non-trivial bus<->phys conversion routines, etc, > >> > > > > Only Xen needs such conversion for swiotlb. > > > > Becky's patches of last week also added __weak annotations to > swiotlb_bus_to_virt, virt_to_bus and bus_to_phys; added the hwdev > parameter to swiotlb_bus_to_phys; and added a weak > swiotlb_arch_address_needs_mapping. I assume that was needed because > powerpc needs non-trivial implementations for those functions. Hmm, what she added are wrappers of virt_to_bus and bus_to_virt. We can remove these and directly use virt_to_bus and bus_to_virt. About __weak address_needs_mapping function, as I said, removing it and using dma_map_ops is a proper solution. > >> so either we can require it that all architectures wishing to use > >> swiotlb define these functions, or have weak default functions that can > >> be overridden by architectures where necessary. > >> > > > > Can you give an example? I don't think IA64, X86_64 or POWER (which > > will use swiotlb) need any __weak functions. If you say other archs > > could use swiotlb, please tell me how they need these __weak. > > > > As I said, Becky's patches added hooks in many of the places we added > them for Xen. I assume that's because powerpc needs them; I have not > seen the arch/powerpc side of those changes. > > J > -- > 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/