Re: Modules loading modules?

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> We have a modular device driver, let's call it xxxmod.  [...]  It []
> might attempt to use an optional module (e.g., zzzverbose) to print
> some device attachment messages.

> First, a required module cannot be optional.  If the desired module
> is not present, or if it is present but its own
> xxx_modcmd(MODULE_CMD_INIT, ...) fails, the failure is propagated
> back to the original "outer" call to module_load() which will also
> fail.

> The second reason why this is not suitable is that the "outer" load
> will add a reference to the module, preventing it from being
> auto-unloaded.

Surely the right answer here is to provide a way to say "refer to this
module, but it's ok for its load to fail, and it's ok for it to get
auto-unloaded", including passing up whatever information is necessary
for the calling module to do something useful in failure cases?

It really seems to me that the module system is there to help us, not
to shackle us, and that if it has properties which are leading to
problems, one of the options we should at the very least be considering
is changing those properties.

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