Kernel prepatch 4.1-rc1

Oh I see. I was thinking in terms of of consumers of an API that don't care about the implementation details beyond "it does what I need, as quickly as I need", in the same way that when I link against glibc I don't care whether or not it has to do some song and dance to get some function to work on some particular kernel (does that happen? I've never had to care).
But that was rather short-sighted - some software will of course end up calling the kernel's own interfaces directly you would at least need an ABI shim to stay around forever.