Tv Guide Spoilers Inbound:

The actor playing Red John was stunned and flattered when he
learned that his character "one of seven final suspects" was the shows big
bad. "Earning this little place in pop culture history was the last
thing I ever expected, he admits "truth be told, I thought I was a red
herring."

McAllister or Smith it seems......
Hopefully that puts to end that someone outside the "seven suspect list"
being red john, sadly Patridge is/was Red John theories will be around
even after the reveal.....
You can also read up on what happens after the red john reveal, story wise.