On 8/28/25 15:57, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> On the one hand unify bio split code, prepare to fix disordered split
> IO; On the other hand fix missing blkcg_bio_issue_init() and
> trace_block_split() for split IO.
Hmmm... Shouldn't that be a prep patch with a fixes tag for backport ?
Because that "fix" here is not done directly but is the result of calling
bio_submit_split_bioset().
>
> Noted commit 319ff40a5427 ("md/raid0: Fix performance regression for large
> sequential writes") already fix disordered split IO by converting bio to
> underlying disks before submit_bio_noacct(), with the respect
> md_submit_bio() already split by sectors, and raid0_make_request() will
> split at most once for unaligned IO. This is a bit hacky and we'll convert
> this to solution in general later.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> ---
> drivers/md/raid0.c | 19 +++++++------------
> 1 file changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index f1d8811a542a..4dcc5133d679 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -463,21 +463,16 @@ static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
> zone = find_zone(conf, &start);
>
> if (bio_end_sector(bio) > zone->zone_end) {
> - struct bio *split = bio_split(bio,
> - zone->zone_end - bio->bi_iter.bi_sector, GFP_NOIO,
> - &mddev->bio_set);
> -
> - if (IS_ERR(split)) {
> - bio->bi_status = errno_to_blk_status(PTR_ERR(split));
> - bio_endio(bio);
> + bio = bio_submit_split_bioset(bio,
> + zone->zone_end - bio->bi_iter.bi_sector,
Can this ever be negative (of course not I think)? But if
bio_submit_split_bioset() is changed to have an unsigned int sectors count,
maybe add a sanity check before calling bio_submit_split_bioset() ?
> + &mddev->bio_set);
> + if (!bio)
> return;
> - }
> - bio_chain(split, bio);
> - submit_bio_noacct(bio);
> - bio = split;
> +
> end = zone->zone_end;
> - } else
> + } else {
> end = bio_end_sector(bio);
> + }
>
> orig_end = end;
> if (zone != conf->strip_zone)
--
Damien Le Moal
Western Digital Research
