Since kernel version 3.2 my network driver doesn’t compile anymore. I downloaded the latest version from Realtek and made the following change in r8168_n.c:
addr = ((void *) page_address(frag->page)) + frag->page_offset;
to
addr = ((void *) page_address(&frag->page)) + frag->page_offset;
After this change the driver compiled and worked again.