From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752845Ab0CZV2G (ORCPT ); Fri, 26 Mar 2010 17:28:06 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:57736 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426Ab0CZV2C (ORCPT ); Fri, 26 Mar 2010 17:28:02 -0400 Date: Fri, 26 Mar 2010 14:23:34 -0700 (PDT) From: Linus Torvalds To: David Daney cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: Re: [PATCH] Protect prefetch macro arguments. In-Reply-To: <4BAD248D.7070603@caviumnetworks.com> Message-ID: References: <1269636240-8895-1-git-send-email-ddaney@caviumnetworks.com> <4BAD248D.7070603@caviumnetworks.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 26 Mar 2010, David Daney wrote: > On 03/26/2010 02:04 PM, Linus Torvalds wrote: > > > > > > On Fri, 26 Mar 2010, David Daney wrote: > > > > > > The GCC built-in __builtin_prefetch() is a vargs function. If we > > > don't wrap the macro parameter in parentheses, a comma operator in the > > > actual argument list might cause unintended parameters to be passed to > > > __builtin_prefetch(). > > > > This seems totally pointless and actively wrong. > > Pointless, perhaps. But 'actively wrong'? Are you sure about that? Yes, I'm sure about that. Your commit message was actively misleading, and the end result is worse than the original and shows a lack of understanding of the C preprocessor. IOW, very much "actively wrong". Linus