We have been told by Linus that we're not allowed to break userland API once the code gets
merged to the linux kernel. We've got mistakes made 8 years ago, and fixed in better API 5
years ago, that we still have to implement because we're not allowed to break API.
It means that if you're unsure of maintaining an API today, you're really scared of merging it
and having to maintain it 5 years down the line when you've added better APIs and nobody in
their right mind is using the old software stack.