search for: inner_guard

This used to be a single patch, but I split it into two with the addition of struct Scatterlist. Again a bit new with Rust submissions. I was told by Gary Guo to rebase on top of rust-next, but it seems *very* behind? The first patch does not build on its own due to a dead_code warning. It is hard to not have dead code when one is adding infrastructure to be used by others at a later