[$] Red-black trees for BPF programs

Most of the kernel's code is written in C and intended to be run directlyon the underlying hardware. That situation is changing in a few ways,though; one of those is the ability to write kernel code for the BPFvirtual machine. The 6.3 kernel release will include a new API making the red-black tree data structure available to BPFprograms. Beyond being an interesting feature in its own right, this newAPI shows how BPF is bringing a different approach to kernel programming -and to the C language in general.