On Mon, Aug 10, 2020 at 11:19:15AM +0800, Ming Lei wrote:
> +++ b/include/linux/bvec.h
> @@ -117,11 +117,18 @@ static inline bool bvec_iter_advance(const struct bio_vec *bv,
> return true;
> }
>
> +static inline void bvec_iter_skip_zero_bvec(struct bvec_iter *iter)
> +{
> + iter->bi_bvec_done = 0;
> + iter->bi_idx++;
> +}
> +
> #define for_each_bvec(bvl, bio_vec, iter, start) \
> for (iter = (start); \
> (iter).bi_size && \
> ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
> - bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
> + (bvl).bv_len ? bvec_iter_advance((bio_vec), &(iter), \
> + (bvl).bv_len) : bvec_iter_skip_zero_bvec(&(iter)))
>
What if you have two zero-length bvecs in a row? Won't this just skip
the first one?
It would seem better to me to put the bv_len test in bvec_iter_advance()
instead of making the macro more complicated.
