Using Rust for kernel development

As "fake Linus" I can just acknowledge the protocol here: I am happy about Rust when done right (read: with true grit) and don't mind to go first.

However during review I did point out that the security hurdles that Rust can help to solve are not in drivers, and I pointed to filesystems and suggested that the developers look at reimplementing the (then out-of-tree) ksmbd in Rust. ksmbd was then merged unbeknownst to me and my worries confirmed to be true as some out-of-bounds bugs (which are impossible in Rust) surfaced immediately.