Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 17 Feb 2003 14:04:23 -0300 | From | Werner Almesberger <> | Subject | Re: [RFC] Migrating net/sched to new module interface |
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Roman Zippel wrote: > Let's stay at the main problem, we have find out when it's safe to delete > an object. For dynamic objects you have the following options: [...] > Static objects and functions are freed by the module code and usually we [...]
Okay so far.
> If we exclude the possibly-wait-forever-option, do you see the problem > for dynamic objects which also contain references to static data/ > functions?
You mean that two locking mechanisms are used, where one of them shouldn't be doing all that much ? Well, yes.
Now, is this a problem, or just a symptom ? I'd say it's a symptom: we already have a perfectly good locking/synchronization method, and that's through the register/unregister interface, so the module-specific part is unnecessary.
That much about the theory. Of course, in real life, we have to face a few more problems:
- if callbacks can happen after apparently successful "unregister", we die - if accesses to other static data owned by a module can happen after apparently successful "unregister", we may die - if a module doesn't "unregister" at all, we die too
But all these problems equally affect code that does other things that can break a callback/access, e.g. if we destroy *de->data immediately after remove_proc_entry returns.
So this is not a module-specific problem.
Agreed ?
- Werner
-- _________________________________________________________________________ / Werner Almesberger, Buenos Aires, Argentina wa@almesberger.net / /_http://www.almesberger.net/____________________________________________/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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