bio_chain_and_submit
return bio_chain_and_submit(bio, bio_alloc(bdev, nr_pages, opf, gfp));
*biop = bio_chain_and_submit(*biop, bio);
*biop = bio_chain_and_submit(*biop, bio);
*biop = bio_chain_and_submit(*biop, bio);
prev = bio_chain_and_submit(prev, bio);
prev = bio_chain_and_submit(prev, bio);
struct bio *bio_chain_and_submit(struct bio *prev, struct bio *new);