Re: Module Refcount & Stuff mini-FAQ

[Werner Almesberger <wa@almesberger.net>]

Rusty Russell wrote:
> Q: When does try_module_get(owner) fail?
> A: When the module is not ready to be entered (ie. still in
>    init_module) or it is being removed.  It fails to prevent you
>    entering the module as it is being discarded (init might fail, or
>    it's being removed).

I'd suggest "It fails in order to [...]" to avoid the "does work
exactly NOT as advertised" ambiguity ;-)

> Q: But modules call my register() routine which wants to call back
>    into one of the function pointers immediately, and so
>    try_module_get() fails!
> A: You're being called from the module, so someone already has a
>    reference (unless there's a bug), so you don't need a
>    try_module_get().

Hmm, I haven't really looked at your new code, but this sounds as
if try_module_get gets an exclusive lock. Is this true ? Doesn't
seem to make sense to me.

> Hope that helps?

Don't you want to repeat the golden rule at the end, just as a
polite reminder ? :-) (Just kidding.)

- Werner

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 / Werner Almesberger, Buenos Aires, Argentina         wa@almesberger.net /
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