As NVIDIA still seem to be unable to produce an up-to-date driver, there are a bewildering number of ‘patches’ out for various kernel versions and driver combinations..

I have found a good link to a ‘3.11’ patch for NVIDIA driver 331.17 and kernel 3.12 (patching just nv-linux.h)  here:
http://pastebin.com/gxKDqu9N
I would normally credit the author, but it is posted by ‘A Guest’, so I will just mention that the link was from the linuxsysconfig site..

I have been using driver 331.17 on kernel 3.12 since it was released, and – so far – it seems to be working OK..    I should mention that I am not using it for gaming!

Robert Gadsdon.  November 6, 2013.