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From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Andreas Dilger <adilger@sun.com>
Subject: [PATCH 3/3] vfs: O_* bit numbers uniqueness check fix 2
Date: Tue, 16 Mar 2010 09:08:54 +0800	[thread overview]
Message-ID: <20100316011118.822047386@intel.com> (raw)
In-Reply-To: 20100316010851.331048488@intel.com

[-- Attachment #1: fcntl_init-O_RDONLY-2 --]
[-- Type: text/plain, Size: 980 bytes --]

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 <adilger@sun.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 fs/fcntl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-mm.orig/fs/fcntl.c	2010-03-12 23:11:46.000000000 +0800
+++ linux-mm/fs/fcntl.c	2010-03-12 23:12:05.000000000 +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(18 != HWEIGHT32(
+	BUILD_BUG_ON(19 - 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	|



  parent reply	other threads:[~2010-03-16  1:12 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-16  1:08 [PATCH 0/3] O_* bit numbers uniqueness check patches Wu Fengguang
2010-03-16  1:08 ` [PATCH 1/3] vfs: O_* bit numbers uniqueness check Wu Fengguang
2010-03-16  1:08 ` [PATCH 2/3] vfs: O_* bit numbers uniqueness check fix Wu Fengguang
2010-03-16  1:08 ` Wu Fengguang [this message]
  -- strict thread matches above, loose matches on Subject: below --
2010-03-16  1:36 [PATCH 0/3] O_* bit numbers uniqueness check patches (V2) Wu Fengguang
2010-03-16  1:36 ` [PATCH 3/3] vfs: O_* bit numbers uniqueness check fix 2 Wu Fengguang

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