From: Keith Owens <kaos@ocs.com.au>
To: lkml <linux-kernel@vger.kernel.org>
Subject: Re: Registering for notifier chains in modules (was Linux 2.4.21-rc3 - ipmi unresolved) 
In-reply-to: Your message of "Mon, 26 May 2003 23:45:39 EST."
             <3ED2ED73.7090300@acm.org> 
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Date: Tue, 27 May 2003 15:30:43 +1000
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On Mon, 26 May 2003 23:45:39 -0500, 
Corey Minyard <minyard@acm.org> wrote:
>Keith Owens wrote:
>>>Why can't you have a module id in the notifier chain, and use a boolean
>>>to tell if it is set, or something similar to that?  That way you could
>>>mix them, if the bool is set then do the try_in_module_count thing, if
>>>not then just call the function.  It does add some components to the
>>>register structure, but that shouldn't hurt anything besides taking a
>>>little more memory.
>>
>>It is a change of API in a 2.4 kernel.  Not a good idea.
>>
>Does adding a field to a structure (where the user does not have to do
>anything with the
>field) change the API?  That would be the only API change here.

The user does have to do something.  Every piece of code that calls
notify_register has to set the new field to __THIS_MODULE.  WIthout
that field being set, you are no better off, the race still exists.

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