[PATCH 3/3] vfs: O_* bit numbers uniqueness check fix 2

[PATCH 3/3] vfs: O_* bit numbers uniqueness check fix 2

[Wu Fengguang]

[-- 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	|

[PATCH 0/3] O_* bit numbers uniqueness check patches (V2)

[Wu Fengguang]

Andrew,

Please take these 3 patches. They are against todays's mmotm.

Sorry for the confusion!

Note that the FMODE_EXEC change is moved as the last one, so that when
removing FMODE_EXEC from the O_* namespace, the commit can be simply
reverted.

Thanks,
Fengguang

[PATCH 1/3] vfs: O_* bit numbers uniqueness check

[Wu Fengguang]

[-- Attachment #1: mutt-wfg-t61-1000-6194-5 --]
[-- Type: text/plain, Size: 1909 bytes --]

The O_* bit numbers are defined in 20+ arch/*, and can silently overlap.
Add a compile time check to ensure the uniqueness as suggested by David
Miller.

Cc: David Miller <davem@davemloft.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Jamie Lokier <jamie@shareable.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---

 fs/fcntl.c                  |   14 ++++++++++++--
 include/asm-generic/fcntl.h |    4 ++++
 2 files changed, 16 insertions(+), 2 deletions(-)

--- linux-mm.orig/fs/fcntl.c	2010-03-16 09:18:28.000000000 +0800
+++ linux-mm/fs/fcntl.c	2010-03-16 09:32:17.000000000 +0800
@@ -739,11 +739,21 @@ void kill_fasync(struct fasync_struct **
 }
 EXPORT_SYMBOL(kill_fasync);
 
-static int __init fasync_init(void)
+static int __init fcntl_init(void)
 {
+	/* please add new bits here to ensure allocation uniqueness */
+	BUILD_BUG_ON(17 != HWEIGHT32(
+		O_RDONLY	| O_WRONLY	| O_RDWR	|
+		O_CREAT		| O_EXCL	| O_NOCTTY	|
+		O_TRUNC		| O_APPEND	| O_NONBLOCK	|
+		__O_SYNC	| O_DSYNC	| FASYNC	|
+		O_DIRECT	| O_LARGEFILE	| O_DIRECTORY	|
+		O_NOFOLLOW	| O_NOATIME	| O_CLOEXEC
+		));
+
 	fasync_cache = kmem_cache_create("fasync_cache",
 		sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
 	return 0;
 }
 
-module_init(fasync_init)
+module_init(fcntl_init)
--- linux-mm.orig/include/asm-generic/fcntl.h	2010-03-16 09:31:16.000000000 +0800
+++ linux-mm/include/asm-generic/fcntl.h	2010-03-16 09:33:30.000000000 +0800
@@ -3,6 +3,10 @@
 
 #include <linux/types.h>
 
+/*
+ * When introducing new O_* bits, please check its uniqueness in fcntl_init().
+ */
+
 #define O_ACCMODE	00000003
 #define O_RDONLY	00000000
 #define O_WRONLY	00000001

[PATCH 2/3] vfs: O_* bit numbers uniqueness check fix

[Wu Fengguang]

[-- 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	2010-03-16 09:35:47.000000000 +0800
+++ linux-mm/fs/fcntl.c	2010-03-16 09:36:01.000000000 +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	|

[PATCH 3/3] vfs: O_* bit numbers uniqueness check fix 2

[Wu Fengguang]

[-- Attachment #1: fcntl_init-O_RDONLY --]
[-- Type: text/plain, Size: 1170 bytes --]

Follow the comment by Eric:

	Until the FMODE_ and O_ bits do not overload I think we need to check
	FMODE_EXEC and FMODE_NONOTIFY (if you have that one) inside fcntl_init()
	as well.  I guess I'll send a patch to someone ?Al? to add FMODE_EXEC to
	the list....

CC: Eric Paris <eparis@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 fs/fcntl.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- linux-mm.orig/fs/fcntl.c	2010-03-16 09:36:01.000000000 +0800
+++ linux-mm/fs/fcntl.c	2010-03-16 09:36:23.000000000 +0800
@@ -742,13 +742,14 @@ EXPORT_SYMBOL(kill_fasync);
 static int __init fcntl_init(void)
 {
 	/* please add new bits here to ensure allocation uniqueness */
-	BUILD_BUG_ON(18 - 1 /* for O_RDONLY being 0 */ != 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	|
 		__O_SYNC	| O_DSYNC	| FASYNC	|
 		O_DIRECT	| O_LARGEFILE	| O_DIRECTORY	|
-		O_NOFOLLOW	| O_NOATIME	| O_CLOEXEC
+		O_NOFOLLOW	| O_NOATIME	| O_CLOEXEC	|
+		FMODE_EXEC
 		));
 
 	fasync_cache = kmem_cache_create("fasync_cache",