title: How to implement a new system call that returns 2*(integer passed) in linux 4.19.20?
body: <p>All the online tutorials are for the system calls that do not return anything. I want a system call that prints twice the argument passed in printk.</p>
  
  <p>Someone please provide a step by step approach. </p>
  
  <p>Thank you for giving your time!</p>