RieserFS isn't distributed as a kernel patch any more; it finally made it into the official stable kernel.
In general, you will need to at least unpack and configure the kernel before you can compile anything against the kernel headers (various #defines get set up by the configuration stage). If you have a distro's standard kernel then you can probably just install a package.
An RPM search for kernel-headers yields quite a few entries, in quite a few configurations:
http://www.rpmfind.net/linux/rpm2htm...mit=Search+...
