Hash table implementation

Hi,

This commit shows that jenkins hash
function(http://en.wikipedia.org/wiki/Jenkins_hash_function) is
implemented in kernel :

commit 60d509c823cca21e77d537bd356785f7cfe8f0d1
Author: Jozsef Kadlecsik [off-list ref]
Date:   Fri Dec 3 02:39:01 2010 +0000

    The new jhash implementation
 <snip>

I could not find any good documentation describing how to use it. Only
thing i could do is to read codes which uses it, like 

/net/netfilter/xt_NFQUEUE.c. I have got some idea about how it works.
But a good documentation would have been better. Like this one
describing linux's implementation of doubly linked list :

http://isis.poly.edu/kulesh/stuff/src/klist/ 

It describes how i can use this even in user land code. If i could do
this for jhash then the understanding would have been better.

Cheers.