bio_advance_iter
bio_advance_iter(bio, &bio->bi_iter, bytes);
bio_advance_iter(bio, &iter, iter.bi_size);
bio_advance_iter(buf->bio, &buf->iter, f->iter.bi_size);
bio_advance_iter(check, &citer, bv.bv_len);
bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
bio_advance_iter(bio, &bio->bi_iter, bv.bv_len);
bio_advance_iter((it)->bio, &(it)->iter, __cur_n); \
bio_advance_iter(it->bio, &it->iter, bytes);