On 7/20/22 23:24, Christoph Hellwig wrote:
> Prepare for reusing blk_bio_segment_split for (file system controlled)
> splits of REQ_OP_ZONE_APPEND bios by letting the caller control the
> maximum size of the bio.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Looks good. Though I think this patch could wait for the actual users of
this change.
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> ---
> block/blk-merge.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index e657f1dc824cb..1676a835b16e7 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -252,11 +252,12 @@ static bool bvec_split_segs(const struct request_queue *q,
> * @bio: [in] bio to be split
> * @bs: [in] bio set to allocate the clone from
> * @segs: [out] number of segments in the bio with the first half of the sectors
> + * @max_bytes: [in] maximum number of bytes per bio
> *
> * Clone @bio, update the bi_iter of the clone to represent the first sectors
> * of @bio and update @bio->bi_iter to represent the remaining sectors. The
> * following is guaranteed for the cloned bio:
> - * - That it has at most get_max_io_size(@q, @bio) sectors.
> + * - That it has at most @max_bytes worth of data
> * - That it has at most queue_max_segments(@q) segments.
> *
> * Except for discard requests the cloned bio will point at the bi_io_vec of
> @@ -266,14 +267,12 @@ static bool bvec_split_segs(const struct request_queue *q,
> * split bio has finished.
> */
> static struct bio *blk_bio_segment_split(struct request_queue *q,
> - struct bio *bio,
> - struct bio_set *bs,
> - unsigned *segs)
> + struct bio *bio, struct bio_set *bs, unsigned *segs,
> + unsigned max_bytes)
> {
> struct bio_vec bv, bvprv, *bvprvp = NULL;
> struct bvec_iter iter;
> unsigned nsegs = 0, bytes = 0;
> - const unsigned max_bytes = get_max_io_size(q, bio) << 9;
> const unsigned max_segs = queue_max_segments(q);
>
> bio_for_each_bvec(bv, bio, iter) {
> @@ -347,7 +346,8 @@ void __blk_queue_split(struct request_queue *q, struct bio **bio,
> split = blk_bio_write_zeroes_split(q, *bio, bs, nr_segs);
> break;
> default:
> - split = blk_bio_segment_split(q, *bio, bs, nr_segs);
> + split = blk_bio_segment_split(q, *bio, bs, nr_segs,
> + get_max_io_size(q, *bio) << SECTOR_SHIFT);
> break;
> }
>
--
Damien Le Moal
Western Digital Research
