Re: Registering for notifier chains in modules (was Linux 2.4.21-rc3 - ipmi unresolved)

[Keith Owens]

On Mon, 26 May 2003 23:45:39 -0500, 
Corey Minyard <[e-mail]> 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.