From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 12 Aug 2001 23:29:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 12 Aug 2001 23:29:25 -0400 Received: from pizda.ninka.net ([216.101.162.242]:24966 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id ; Sun, 12 Aug 2001 23:29:15 -0400 Date: Sun, 12 Aug 2001 20:29:18 -0700 (PDT) Message-Id: <20010812.202918.48532196.davem@redhat.com> To: torvalds@transmeta.com Cc: andrea@suse.de, eyal@eyal.emu.id.au, linux-kernel@vger.kernel.org Subject: Re: 2.4.8aa1 From: "David S. Miller" In-Reply-To: In-Reply-To: <20010812190202.H737@athlon.random> X-Mailer: Mew version 2.0 on Emacs 21.0 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds Date: Sun, 12 Aug 2001 10:21:58 -0700 (PDT) On Sun, 12 Aug 2001, Andrea Arcangeli wrote: > So I believe a kind of page_to_bus64 should be implemented, and it should > possibly return dma64_addr_t typedeffed as 'unsigned long long'. Fair enough, that sounds like a good idea too. I agree with the dma64_addr_t type, but I don't know if I agree with the logistics of how drivers go about doing things and what the interfaces are that an architecture implements. First, maybe I'm confused about intent. Are we trying to just hack together something quick for 2.4.x that allows PCI drivers on highmem machines to get at the complete low 4GB of physical memory, even the highmem parts? If this is the case, then I have no strong opinions about what you do because I know I will be able to retrofit my ports into whatever interfaces you come up with for that (f.e. the pci_kmap()/pci_kunmap() stuff). But if this is more far reaching, ie. a 64-bit addressing API for drivers, my thinking is that this is a larger problem to solve. For example, if you're talking seriously about sending page/off/len triplets to the drivers (which is what we want in the end), then with that I can whip together something really nice and portable in about a weekend of thinking and hacking. The only reason I haven't done this work yet is strictly because the drivers aren't getting pages yet (well, the zerocopy aware networking drivers are). It was my understanding that this is the bit that Jens Axboe and Andrea are working on. Later, David S. Miller davem@redhat.com