Re: SET_MODULE_OWNER?

Jeff Garzik (jgarzik@pobox.com)
Mon, 07 Apr 2003 22:27:28 -0400


Rusty Russell wrote:
> In message <3E91C398.9070400@pobox.com> you write:
>
>>Rusty Russell wrote:
>>
>>>I thought it was completely useless, hence deprecated.
>>>
>>>Anyone have any reason to defend it?
>>
>>
>>It's used to allow source compatibility with all kernels, old or new.
>>
>>Thus it is in active use, and should not be removed.
>
>
> Inside individual drivers, or a set of compat macros, it makes sense.
> But as a general module.h primitive it doesn't.
>
> Imagine a structure adds an owner field in 2.5. This macro doesn't
> help you, you need a specific compat macro for that struct.

no, SET_MODULE_OWNER is quite intentionally independent of the struct.
It only requires a consisnent naming in the source, between structures
that may use the macro.

That's a feature.

> ie. AFAICT it only buys you 2.2 compatibility, and even then only if
> you #define it at the top of your driver.

no, farther back than that, to infinity and beyond :) The idea of the
macro is that on earlier kernels, it is simply a no-op, and module
refcounting is handled by other means.

> I still don't understand: please demonstrate a use in existing source.

demonstrate? grep for it. It's used quite a bit. Removal of
SET_MODULE_OWNER looks to me to be pointless churn for negative gain.
If if you wish to pointedly ignore the old-source compatibility angle,
it is a nice convenience macro.

Jeff

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