Description
===========
    A simple message passing mechanism across processes using Char driver. This is only for learining kernel interanls.

1. Char device driver module is created for sudo device. 

2. Application can read and write msg from/to the device in the following structure format 

struct sb_msg {
    unsigned short type:3;
    unsigned short len:13;
    unsigned char  data[0];
};

3. Driver will keep the messages in linked list and returns message sequencially on read.

4. Blocking and non-blocking read modes are supported.

5. Synchronozation is taken care.


TODO List
========
1. Create a proc entry to read number of message in the list and print messages.

2. Create a worker to reverse the message in in-list and add to out-list. Read will happen from out-list and write will write to in-list.
  i. worker can be a tasklet, work queue, delayed work queue or kernel thread. 
  ii. type of thread will be passed as module param.