C interop is excellent and has been for years. The one piece that still needs unstable is defining/exposing varargs functions (support for calling them was stabilized many years ago). You can write almost anything you can write in C in (partly unsafe) Rust, in fact there are projects like c2rust that automate this translation.
These new features are all about making things that the kernel devs need possible in safe Rust. This often requires support for some quite fancy abstractions, some of which cannot be expressed in current stable Rust.
These new features are all about making things that the kernel devs need possible in safe Rust. This often requires support for some quite fancy abstractions, some of which cannot be expressed in current stable Rust.