visibility of symbols defined in a kld module ?

I have the following problem while building a compat layer for compiling
linux drivers on FreeBSD:
a piece of code (let's restrict to a kld if it makes things simpler)
needs to register some information to the system calling a function:

        usb_register(&some_data)

where some_data is a structure containing various info (callbacks etc)
for the code.
The problem is, i need to hook the argument of usb_register() to the kld.

If i write

   /* in linux_module_header.h */
        extern void *my_module_info;

        #define usb_register(p)         my_module_info = p

   /* in linux_driver_stub.c, linked together with the rest of the code */

        #include "linux_module_header.h"
        void *my_module_info;

I get what i want, but then my_module_info is present in all modules
compiled with the same trick, so what happens when the modules are
kldloaded ? Does this symbol conflict (i.e. is this equivalent to RTLD_GLOBAL)
or each one sees its own symbols (i.e. like RTLD_LOCAL) ?

And besides, this would almost surely fail if i compile these things
not as modules but as part of the kernel.

The other trick i can think of is using some preprocessor-magic to
create unique names for the symbol, e.g. compile each kld with  
-DDRIVER_NAME=pwc, -DDRIVER_NAME=gspca, -DDRIVER_NAME=dvb and then have

   /* in linux_module_header.h */
        #define MODINFO_NAME    module_ ## DRIVER_NAME ## _info

        extern void *MODINFO_NAME;  
 
        #define usb_register(p)         MODINFO_NAME = p
   
   /* in linux_driver_stub.c, linked together with the rest of the code */
 
        #include "linux_module_header.h"
        void *MODINFO_NAME;
 
This way each module has a different symbol and there are no conflict.
Other ideas ?

	cheers
	luigi