Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761286AbYJJRMl (ORCPT ); Fri, 10 Oct 2008 13:12:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758642AbYJJRMc (ORCPT ); Fri, 10 Oct 2008 13:12:32 -0400 Received: from palinux.external.hp.com ([192.25.206.14]:35046 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758056AbYJJRMb (ORCPT ); Fri, 10 Oct 2008 13:12:31 -0400 Date: Fri, 10 Oct 2008 11:12:15 -0600 From: Matthew Wilcox To: Yinghai Lu Cc: Andrew Morton , Jesse Barnes , FUJITA Tomonori , grundler@parisc-linux.org, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] pci: print out DMA mask info Message-ID: <20081010171214.GG25780@parisc-linux.org> References: <1223506943-6543-1-git-send-email-yinghai@kernel.org> <20081009211837.GC18444@colo.lackof.org> <20081010114002D.fujita.tomonori@lab.ntt.co.jp> <200810100848.09557.jbarnes@virtuousgeek.org> <86802c440810100919xf79f406x403988da7988edc9@mail.gmail.com> <20081010163350.GF25780@parisc-linux.org> <48EF86E9.8030408@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48EF86E9.8030408@kernel.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1565 Lines: 40 On Fri, Oct 10, 2008 at 09:46:33AM -0700, Yinghai Lu wrote: > Matthew Wilcox wrote: > > > > By the way, commit 8f286c33f1e838d631f4a3260b33efce4bc5973c is a really > > bad idea. It is very helpful to see which bitmasks are used by real > > devices, and which ones aren't. It should be reverted, IMO. > > why? did you point to wrong commit? No, that's the commit I meant. > commit 8f286c33f1e838d631f4a3260b33efce4bc5973c > Author: Andrew Morton > Date: Thu Oct 18 03:05:07 2007 -0700 > > -#define DMA_BIT_MASK(n) ((1ULL<<(n))-1) > +#define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1)) > > -#define DMA_64BIT_MASK (~0ULL) > +/* > + * NOTE: do not use the below macros in new code and do not add new definitions > + * here. > + * > + * Instead, just open-code DMA_BIT_MASK(n) within your driver Open-coding DMA_BIT_MASK() within your driver means that we no longer have a canonical list of DMA masks in one place. Instead we have to grep the entire tree and come up with more-or-less complex scripts to figure out which bit masks are actually in use. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step." -- 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/