You followed a link to a place that I don't keep anything any more.

Depending on what you are looking for (/source/mdadm/patch), you might like to try:

http://neil.brown.name/
http://neil.brown.name/mdadm/
http://neil.brown.name/git/mdadm/
http://neil.brown.name/git/
http://www.kernel.org/pub/linux/utils/mdadm/