[LSF/MM/BPF TOPIC] State Of The Page

[Kent Overstreet]

On Fri, Jan 19, 2024 at 04:24:29PM +0000, Matthew Wilcox wrote:
>  - What are we going to do about bio_vecs?

For bios and biovecs, I think it's important to keep in mind the
distinction between the code that owns and submits the bio, and the
consumer underneath.

The code underneath could just as easily work with pfns, and the code
above got those pages from somewhere else, so it doesn't _need_ the bio
for access to those pages/folios (it would be a lot of refactoring
though).

But I've been thinking about going in a different direction - what if we
unified iov_iter and bio? We've got ~3 different scatter-gather types
that an IO passes through down the stack, and it would be lovely if we
could get it down to just one; e.g. for DIO, pinning pages right at the
copy_from_user boundary.