[PATCH v3 03/10] block: handle split correctly for user meta bounce buffer

[Christoph Hellwig]

On Fri, Aug 23, 2024 at 04:08:03PM +0530, Anuj Gupta wrote:
> Copy back the bounce buffer to user-space in entirety when the parent
> bio completes.

This looks odd to me.  The usual way to handle iterating the entire
submitter controlled data is to just iterate over the bvec array, as
done by bio_for_each_segment_all/bio_for_each_bvec_all for the bio
data.  I think you want to do the same here, probably with a
similar bip_for_each_bvec_all or similar helper.  That way you don't
need to stash away the iter.  Currently we have the field for that,
but I really want to split up struct bio_integrity_payload into
what is actually needed for the payload and stuff only needed for
the block layer autogenerated PI (bip_bio/bio_iter/bip_work).