questions about backport to 3.8/3.9/4.0

Hi,

[ Sorry. This is a resend with proper tag in the subject line. ]

I want to backport the following three patches (currently in trunk 5.0)
to 3.8/3.9/4.0:

https://reviews.llvm.org/rL305560
https://reviews.llvm.org/rL305608
https://reviews.llvm.org/rL306685

Some BPF users want them since their product needs to work on
old linux distribution which has older versions of LLVM.

Could somebody (maybe Tom Stellard or others) help clarify whether it
is possible and what is the procedure/timeline for backporting?

Thanks!

Yonghong