I think they resist that mainly because it makes it easier for companies that don't want to upstream their drivers, and nobody else. Currently, if there is say

I think they resist that mainly because it makes it easier for companies that don't want to upstream their drivers, and nobody else. Currently, if there is say a better, more efficient way to do some common task ,say storage drivers, do, you can just go in and refactor all of that. With common interface, you're doomed. You might implement the better way and give it in API, but you can't force anyone to use it, and you can't deprecate the old one. You also have to keep the old behaviour *forever*, even for things that "do not break userspace" so it's even bigger maintenance burden. And what if your API is wrong ? Still gotta keep it... and someone might still use it and trip on the wrongness