Linux Module Stacking Example

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What is module stacking?

New modules using the symbols exported by old modules.

Examples of modules stacking in Linux Kernel?


  • Msdos filesystem relies on symbols exported by fat module
  • Parallel port printer driver (lp) relies on symbols exported by generic parallel port driver (parport)

Let's write a sample device driver code which exports a function myadd performing addition of two numbers:


Code:


Now, we will write another module which uses the exported function:

Code:

Makefile to Compile two modules:


Build the modules by running "make", Load the first module and then second module using insmod.

 Output:



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