How to wake_up the wait_queue of a socket?

[horseriver]

On Tue, Jan 15, 2013 at 12:25:10PM -0500, Valdis.Kletnieks at vt.edu wrote:
> On Mon, 14 Jan 2013 17:50:03 +0800, horseriver said:
> 
> >    When one datagram has reached , How to wake_up the wait_queue of that socket ?
> 
> Please clarify your question - I'm not sure which of the following you mean:
> 
 1) How does the kernel wake up the waiting process when a datagram
 arrives?

  This is my mean !
  
  Thanks