2006-03-22 16:11:11

by Jes Sorensen

Subject: [patch -mm] notifier chain initialization

Hi,

This one is against the -mm tree, description below.

Cheers,
Jes

This patch goes on top of Alan Stern's
notifier-chain-update-api-changes.patch

It restructures the notifier chain initialization macros by
introducing FOO_NOTIFIER_INIT() macros which are used by the
FOO_NOTIFIER_HEAD() macros.

The benefit is that one can use the FOO_NOTIFIER_INIT() macro for
static initialization of a notifier chain.

Signed-off-by: Jes Sorensen <[email protected]>

---
include/linux/notifier.h | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)

Index: linux-2.6/include/linux/notifier.h
===================================================================
--- linux-2.6.orig/include/linux/notifier.h
+++ linux-2.6/include/linux/notifier.h
@@ -64,17 +64,24 @@
(name)->head = NULL; \
} while (0)

-#define ATOMIC_NOTIFIER_HEAD(name) \
- struct atomic_notifier_head name = { \
+#define ATOMIC_NOTIFIER_INIT(name) { \
.mutex = __MUTEX_INITIALIZER((name).mutex), \
.head = NULL }
-#define BLOCKING_NOTIFIER_HEAD(name) \
- struct blocking_notifier_head name = { \
+#define BLOCKING_NOTIFIER_INIT(name) { \
.rwsem = __RWSEM_INITIALIZER((name).rwsem), \
.head = NULL }
+#define RAW_NOTIFIER_INIT(name) { \
+ .head = NULL }
+
+#define ATOMIC_NOTIFIER_HEAD(name) \
+ struct atomic_notifier_head name = \
+ ATOMIC_NOTIFIER_INIT(name)
+#define BLOCKING_NOTIFIER_HEAD(name) \
+ struct blocking_notifier_head name = \
+ BLOCKING_NOTIFIER_INIT(name)
#define RAW_NOTIFIER_HEAD(name) \
- struct raw_notifier_head name = { \
- .head = NULL }
+ struct raw_notifier_head name = \
+ RAW_NOTIFIER_INIT(name)

#ifdef __KERNEL__

2006-03-22 17:05:50

by Alan Stern

Subject: Re: [patch -mm] notifier chain initialization

On 22 Mar 2006, Jes Sorensen wrote:

> Hi,
>
> This one is against the -mm tree, description below.
>
> Cheers,
> Jes
>
> This patch goes on top of Alan Stern's
> notifier-chain-update-api-changes.patch
>
> It restructures the notifier chain initialization macros by
> introducing FOO_NOTIFIER_INIT() macros which are used by the
> FOO_NOTIFIER_HEAD() macros.
>
> The benefit is that one can use the FOO_NOTIFIER_INIT() macro for
> static initialization of a notifier chain.

You probably mean _dynamic_ initialization of a notifier head. The
current code handles static initialization just fine.

There's nothing wrong with doing things like this. I didn't include
initialization macros originally simply because there aren't any
dynamically-initialized notifier heads in the kernel.

Alan Stern

2006-03-22 21:10:31

by Jes Sorensen

Subject: Re: [patch -mm] notifier chain initialization

Alan Stern wrote:
>> The benefit is that one can use the FOO_NOTIFIER_INIT() macro for
>> static initialization of a notifier chain.
>
> You probably mean _dynamic_ initialization of a notifier head. The
> current code handles static initialization just fine.

Actually I meant static, I have a notifier declared within a struct and
a macro that initializes it at compile time - didn't work with the old
code.

But I also use it dynamically where this also benefits it.

> There's nothing wrong with doing things like this. I didn't include
> initialization macros originally simply because there aren't any
> dynamically-initialized notifier heads in the kernel.

There probably will be :)

Cheers,
Jes