Re: [Qemu-devel] [PATCH v10 5/8] module: implement module loading

[Paolo Bonzini]

Il 16/09/2013 12:14, Daniel P. Berrange ha scritto:
> On Mon, Sep 16, 2013 at 12:09:47PM +0200, Paolo Bonzini wrote:
>> Il 16/09/2013 11:51, Fam Zheng ha scritto:
>>> On Mon, 09/16 11:44, Paolo Bonzini wrote:
>>>> Il 16/09/2013 10:59, Daniel P. Berrange ha scritto:
>>>>>> The init function of dynamic module is no longer with
>>>>>> __attribute__((constructor)) as static linked version, and need to be
>>>>>> explicitly called once loaded. The function name is mangled with per
>>>>>> configure fingerprint as:
>>>>>>
>>>>>>     init_$(date +%s$$$RANDOM)
>>>>
>>>> Does this work for a module that calls module_init multiple times?
>>>
>>> Why should a module calls module_init, instead of the main function?
>>
>> I think you mean "why should a module calls register_module_init", and I
>> agree that with this patch a module will not call register_module_init.
>>
>> But a module is still using the module_init macro.
>>
>> With this patch, a module will not be able to use the module_init macro
>> twice.  I am not sure this is an acceptable limitation, especially if we
>> do not have a dependency system within modules and/or load them with
>> G_MODULE_LOCAL/RTLD_LOCAL.
> 
> Why would a module ever want to use the module_init macro twice ?

Because our coding standard is to have each source file do its own
one-time initialization, using static functions and an invocation of
module_init per source file.

The reason is that otherwise you risk having function name conflicts in
the static-link case.

Paolo

> IIUC
> this function is supposed todo one-time initialization work for the .so
> module. Surely any place where a module wanted to use module_init twice
> could be solved by having that module put all its init logic into just
> one function. So I'm not sure I see where the problem is.