Also, rust is only being considered for kernel modules, not kernel core. And even then, only kernel modules that don't need to build on architectures rust doesn

Also, rust is only being considered for kernel modules, not kernel core. And even then, only kernel modules that don't need to build on architectures rust doesn't support. So if you don't need any of those particular modules you can just disable them. In the long term, LLVM/Rust support for more architectures improves, and support for older architectures is dropped, this will become a larger fraction of kernel modules, but it will be a very long time until it is considered for something like ext5.