From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH] vfs: O_* bit numbers uniqueness check fix 2 Date: Fri, 12 Mar 2010 21:42:03 +0800 Message-ID: <20100312134203.GB6502@localhost> References: <201003112211.o2BMBLfm013822@imap1.linux-foundation.org> <6DD92A2F-63EB-44A5-A0B7-DCAD21A9BD2B@sun.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "akpm@linux-foundation.org" , "viro@zeniv.linux.org.uk" , "linux-fsdevel@vger.kernel.org" , "davem@davemloft.net" , "eparis@redhat.com" , "hch@infradead.org" , "jamie@shareable.org" , "rdreier@cisco.com" , "schwab@linux-m68k.org" , "sfr@canb.auug.org.au" To: Andreas Dilger Return-path: Received: from mga14.intel.com ([143.182.124.37]:5360 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751182Ab0CLOfP (ORCPT ); Fri, 12 Mar 2010 09:35:15 -0500 Content-Disposition: inline In-Reply-To: <6DD92A2F-63EB-44A5-A0B7-DCAD21A9BD2B@sun.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Follow the comment by Andreas: It's non-obvious why there are 18 flags listed here, but the hweight is only 17? Presumably this is because O_RDONLY has value 0, but that should at least be listed in a comment, or the test could be written more explicitly, like: BUILD_BUG_ON(18 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( CC: Andreas Dilger Signed-off-by: Wu Fengguang --- fs/fcntl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- linux-mm.orig/fs/fcntl.c 2010-03-12 21:39:01.000000000 +0800 +++ linux-mm/fs/fcntl.c 2010-03-12 21:38:42.000000000 +0800 @@ -742,7 +742,7 @@ EXPORT_SYMBOL(kill_fasync); static int __init fcntl_init(void) { /* please add new bits here to ensure allocation uniqueness */ - BUILD_BUG_ON(17 != HWEIGHT32( + BUILD_BUG_ON(18 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC | O_APPEND | O_NONBLOCK |