Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753950Ab0AINeI (ORCPT ); Sat, 9 Jan 2010 08:34:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752410Ab0AINeH (ORCPT ); Sat, 9 Jan 2010 08:34:07 -0500 Received: from mga01.intel.com ([192.55.52.88]:36576 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751853Ab0AINeG (ORCPT ); Sat, 9 Jan 2010 08:34:06 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.49,246,1262592000"; d="scan'208";a="529869597" Date: Sat, 9 Jan 2010 21:33:42 +0800 From: Wu Fengguang To: Andreas Schwab 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 Message-ID: <20100109133342.GB20015@localhost> References: <20100106065526.GB11368@localhost> <4B443695.5090301@gmail.com> <20100106072029.GA25169@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1741 Lines: 41 On Wed, Jan 06, 2010 at 05:13:54PM +0800, Andreas Schwab wrote: > 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)? You mean to test __O_SYNC | O_DSYNC instead of O_SYNC? -- 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/