You have misunderstood. No, it wasn't an existing thing. This is the code that implements it. That's the point.
The change to fs/namei.c is the code to handle not following symlinks; the rest is some necessary code to create the option and expose it to userland.
(Edit: Rereading I do see a little better what you were saying - I actually looked it up and the code that “originally” implemented not following symlinks, that you’re saying we're now adding an or statement to activate, was 2 lines to expose the option, 2 lines of white space, and 2 lines to implement not following symlinks).