title: how sys_open works?
body: <p>I have write a simple char device driver (mydev) with "open" file operation in it.</p>
  
  <p>In user space application I open this driver node. using open("/dev/mydev", O_RDONLY);
  The open() system call internally calls the sys_open().</p>
  
  <p>I just want to know the follow of how sys_open() function call my driver's open file operation. How VFS handles this, which function it internally calls.</p>