On Thu, Apr 11, 2019 at 08:23:30AM +0200, Christoph Hellwig wrote:
> Instead of needing a special macro to iterate over all pages in
> a bvec just do a second passs over the whole bio. This also matches
> what we do on the release side. The release side helper is moved
> up to where we need the get helper to clearly express the symmetry.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> block/bio.c | 51 ++++++++++++++++++++++----------------------
> include/linux/bvec.h | 5 -----
> 2 files changed, 25 insertions(+), 31 deletions(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index c2a389b1509a..d3490aeb1a7e 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -861,6 +861,26 @@ int bio_add_page(struct bio *bio, struct page *page,
> }
> EXPORT_SYMBOL(bio_add_page);
>
> +static void bio_get_pages(struct bio *bio)
> +{
> + struct bvec_iter_all iter_all;
> + struct bio_vec *bvec;
> + int i;
> +
> + bio_for_each_segment_all(bvec, bio, i, iter_all)
> + get_page(bvec->bv_page);
> +}
> +
> +static void bio_release_pages(struct bio *bio)
> +{
> + struct bvec_iter_all iter_all;
> + struct bio_vec *bvec;
> + int i;
> +
> + bio_for_each_segment_all(bvec, bio, i, iter_all)
> + put_page(bvec->bv_page);
> +}
> +
> static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
> {
> const struct bio_vec *bv = iter->bvec;
> @@ -875,15 +895,6 @@ static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
> bv->bv_offset + iter->iov_offset);
> if (unlikely(size != len))
> return -EINVAL;
> -
> - if (!bio_flagged(bio, BIO_NO_PAGE_REF)) {
> - struct page *page;
> - int i;
> -
> - mp_bvec_for_each_page(page, bv, i)
> - get_page(page);
> - }
> -
> iov_iter_advance(iter, size);
> return 0;
> }
> @@ -963,13 +974,6 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
> if (WARN_ON_ONCE(bio->bi_vcnt))
> return -EINVAL;
>
> - /*
> - * If this is a BVEC iter, then the pages are kernel pages. Don't
> - * release them on IO completion, if the caller asked us to.
> - */
> - if (is_bvec && iov_iter_bvec_no_ref(iter))
> - bio_set_flag(bio, BIO_NO_PAGE_REF);
> -
> do {
> if (is_bvec)
> ret = __bio_iov_bvec_add_pages(bio, iter);
> @@ -977,6 +981,11 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
> ret = __bio_iov_iter_get_pages(bio, iter);
> } while (!ret && iov_iter_count(iter) && !bio_full(bio));
>
> + if (iov_iter_bvec_no_ref(iter))
> + bio_set_flag(bio, BIO_NO_PAGE_REF);
> + else
> + bio_get_pages(bio);
> +
> return bio->bi_vcnt ? 0 : ret;
> }
>
> @@ -1670,16 +1679,6 @@ void bio_set_pages_dirty(struct bio *bio)
> }
> }
>
> -static void bio_release_pages(struct bio *bio)
> -{
> - struct bio_vec *bvec;
> - int i;
> - struct bvec_iter_all iter_all;
> -
> - bio_for_each_segment_all(bvec, bio, i, iter_all)
> - put_page(bvec->bv_page);
> -}
> -
> /*
> * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
> * If they are, then fine. If, however, some pages are clean then they must
> diff --git a/include/linux/bvec.h b/include/linux/bvec.h
> index f6275c4da13a..307bbda62b7b 100644
> --- a/include/linux/bvec.h
> +++ b/include/linux/bvec.h
> @@ -189,9 +189,4 @@ static inline void mp_bvec_last_segment(const struct bio_vec *bvec,
> }
> }
>
> -#define mp_bvec_for_each_page(pg, bv, i) \
> - for (i = (bv)->bv_offset / PAGE_SIZE; \
> - (i <= (((bv)->bv_offset + (bv)->bv_len - 1) / PAGE_SIZE)) && \
> - (pg = bvec_nth_page((bv)->bv_page, i)); i += 1)
> -
> #endif /* __LINUX_BVEC_ITER_H */
> --
> 2.20.1
>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
--
Ming
