On Tue, Dec 01, 2020 at 12:52:51PM +0000, Matthew Wilcox wrote: > But the only reason we want to know 'nr_vecs' is so we can allocate a > BIO which has that many vecs, right? But we then don't actually use the > vecs in the bio because we use the ones already present in the iter. > That was why I had it return 1, not nr_vecs. > > Did I miss something? Right now __bio_iov_bvec_add_pages does not reuse the bvecs in the iter. That being said while we are optmizing this path we might a well look into reusing them..