Re: [PATCH v2 16/51] block: bounce: avoid direct access to bvec table

Matthew Wilcox
2017-06-27T06:12:11Z

On Mon, Jun 26, 2017 at 08:09:59PM +0800, Ming Lei wrote:
> bio_for_each_segment_all(bvec, bio, i) {
> - org_vec = bio_orig->bi_io_vec + i + start;
> -
> - if (bvec->bv_page == org_vec->bv_page)
> - continue;
> + orig_vec = bio_iter_iovec(bio_orig, orig_iter);
> + if (bvec->bv_page == orig_vec.bv_page)
> + goto next;
>
> dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
> mempool_free(bvec->bv_page, pool);
> + next:
> + bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len);
> }
>

I think this might be written more clearly as:

bio_for_each_segment_all(bvec, bio, i) {
orig_vec = bio_iter_iovec(bio_orig, orig_iter);
if (bvec->bv_page != orig_vec.bv_page) {
dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
mempool_free(bvec->bv_page, pool);
}
bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len);
}

What do you think?