How one can define a dependency for modules in kernel,
Example:
got module1 and module2.
How do I say say kernel module2 should be loaded after module1 or module2 is dependent of module1?
Note : module2 is not using any symbol from module1, but still order is important in my use case. so don't relate with moddep in kernel.
For easy solution, you can add symbol in first module and check that symbol in second module init. If symbol is not exported using
EXPORT_SYMBOL
you can return from second module initialization itself.
For details, from header
Linux kernel modules can provide services (called "symbols") for other
modules to use (using one of the EXPORT_SYMBOL variants in the code).
If a second module uses this symbol, that second module clearly depends
on the first module. These dependencies can get quite complex.
depmod creates a list of module dependencies by reading each module
under /lib/modules/version and determining what symbols it exports and
what symbols it needs. By default, this list is written to modules.dep,
and a binary hashed version named modules.dep.bin, in the same
directory. If filenames are given on the command line, only those
modules are examined (which is rarely useful unless all modules are
listed). depmod also creates a list of symbols provided by modules in
the file named modules.symbols and its binary hashed version,
modules.symbols.bin. Finally, depmod will output a file named
modules.devname if modules supply special device names (devname) that
should be populated in /dev on boot (by a utility such as udev).
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