Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754449Ab0AIMjQ (ORCPT ); Sat, 9 Jan 2010 07:39:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754099Ab0AIMjO (ORCPT ); Sat, 9 Jan 2010 07:39:14 -0500 Received: from mail-out.m-online.net ([212.18.0.9]:38854 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754089Ab0AIMjL (ORCPT ); Sat, 9 Jan 2010 07:39:11 -0500 X-Auth-Info: R0ktkecH2e2vLiPLMEuCLeQsd9mCUAjxts53GMTnKiM= From: Andreas Schwab To: Wu Fengguang Cc: Eric Dumazet , Andrew Morton , David Miller , Stephen Rothwell , Al Viro , Christoph Hellwig , Eric Paris , LKML , "linux-fsdevel\@vger.kernel.org" Subject: Re: [PATCH] fs: O_* bit numbers uniqueness check References: <20100106065526.GB11368@localhost> <4B443695.5090301@gmail.com> <20100106072029.GA25169@localhost> X-Yow: The FALAFEL SANDWICH lands on my HEAD and I become a VEGETARIAN... Date: Wed, 06 Jan 2010 10:13:54 +0100 In-Reply-To: <20100106072029.GA25169@localhost> (Wu Fengguang's message of "Wed, 6 Jan 2010 15:20:29 +0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1.91 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1727 Lines: 45 Wu Fengguang writes: > On Wed, Jan 06, 2010 at 03:07:01PM +0800, Eric Dumazet wrote: >> Le 06/01/2010 07:55, Wu Fengguang a écrit : >> > The O_* bit numbers are defined in 20+ arch/*, and hence can silently >> > overlap. Add a boot time check to ensure the uniqueness as suggested >> > by David Miller. >> > >> > CC: David Miller >> > CC: Stephen Rothwell >> > CC: Al Viro >> > CC: Christoph Hellwig >> > CC: Eric Paris >> > Signed-off-by: Wu Fengguang >> > --- >> > { >> > + /* please add new bits here to ensure allocation uniqueness */ >> > + BUG_ON(20 != hweight32( >> > + O_RDONLY | O_WRONLY | O_RDWR | >> > + O_CREAT | O_EXCL | O_NOCTTY | >> > + O_TRUNC | O_APPEND | O_NONBLOCK | >> > + O_SYNC | FASYNC | O_DIRECT | >> > + O_LARGEFILE | O_DIRECTORY | O_NOFOLLOW | >> > + O_NOATIME | O_CLOEXEC | O_RANDOM | >> > + FMODE_EXEC | FMODE_NONOTIFY)); >> > + >> >> I cannot test it, but given O_RDONLY is 0, are you sure 20 bits are actually set ? > > Yes, I tested it. The tricky one is O_SYNC, which actually has two bits.. What if a new architecture wants to use a single bit value (since it does not need backwards compatibility)? Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." -- 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/