Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764083AbXJEWdJ (ORCPT ); Fri, 5 Oct 2007 18:33:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754092AbXJEWc4 (ORCPT ); Fri, 5 Oct 2007 18:32:56 -0400 Received: from gw.goop.org ([64.81.55.164]:56937 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754074AbXJEWcz (ORCPT ); Fri, 5 Oct 2007 18:32:55 -0400 Message-ID: <4706BB8D.9070408@goop.org> Date: Fri, 05 Oct 2007 15:32:45 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.5 (X11/20070727) MIME-Version: 1.0 To: Andrew Morton CC: schwab@suse.de, rpjday@mindspring.com, bbpetkov@yahoo.de, linux-kernel@vger.kernel.org, muli@il.ibm.com, satyam@infradead.org, amitkale@netxen.com, achim_leubner@adaptec.com Subject: Re: [PATCH 1/1] unify DMA_..BIT_MASK definitions: v3.1 References: <20070918194647.GA23800@gollum.tnic> <20071005124705.6584e2f9.akpm@linux-foundation.org> <4706A20A.5060603@goop.org> <20071005140050.655b7727.akpm@linux-foundation.org> <4706AC8D.1030100@goop.org> <20071005152450.a7652b75.akpm@linux-foundation.org> In-Reply-To: <20071005152450.a7652b75.akpm@linux-foundation.org> X-Enigmail-Version: 0.95.3 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: 804 Lines: 19 Andrew Morton wrote: > Well yes, but DMA_BIT_MASK(0) invokes undefined behaviour, generates a > compiler warning and evaluates to 0xffffffffffffffff (with my setup). > > That won't be a problem in practice, but it is strictly wrong and doesn't set > a good exmaple for the children ;) > It's interesting that it doesn't seem to be possible to define this without invoking some undefined behaviour. But a device that supports 0 bits of DMA address probably isn't terribly concerned about this - it's certainly better than making 64 bit masks warty. 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/