In order to backport the Linux kernel we must divide and conquer the tasks at hand.
There are currently two components to the backports effort.
compat is a shared module / headers that implements newer features for usage on older kernels.
compat-drivers is the framework that pulls code from the Linux kernel, adds the compat module and backports features that compat could not backport within its module / headers.
Getting all required code
To be able to make releases and test building releases however you need quite a bit more code. The setup is simplified with scripts from the compat.git tree. To set your system up for the first time you can run:
wget https://github.com/mcgrof/compat/raw/master/bin/get-compat-trees wget https://github.com/mcgrof/compat/raw/master/bin/get-compat-kernels chmod 755 get-compat-trees get-compat-kernels ./get-compat-trees ./get-compat-kernels