Re: [PATCH v3] md/raid10: don't call bio_start_io_acct twice for bio which experienced read error

[Song Liu]

On Mon, Mar 13, 2023 at 6:23 PM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
>
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> handle_read_error() will resumit r10_bio by raid10_read_request(), which
> will call bio_start_io_acct() again, while bio_end_io_acct() will only
> be called once.
>
> Fix the problem by don't account io again from handle_read_error().
>
> Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting")
> Suggested-by: Song Liu <song@xxxxxxxxxx>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>

Applied to md-next.

Thanks!
Song

> ---
> Changes in v3:
>  - use r10_bo->start_time instead of adding a new paramater.
> Changes in v3:
>  - Change the patch title
>
>  drivers/md/raid10.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 6c66357f92f5..3483fdf796ec 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -1244,7 +1244,8 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio,
>         }
>         slot = r10_bio->read_slot;
>
> -       if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
> +       if (!r10_bio->start_time &&
> +           blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
>                 r10_bio->start_time = bio_start_io_acct(bio);
>         read_bio = bio_alloc_clone(rdev->bdev, bio, gfp, &mddev->bio_set);
>
> @@ -1574,6 +1575,7 @@ static void __make_request(struct mddev *mddev, struct bio *bio, int sectors)
>         r10_bio->sector = bio->bi_iter.bi_sector;
>         r10_bio->state = 0;
>         r10_bio->read_slot = -1;
> +       r10_bio->start_time = 0;
>         memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) *
>                         conf->geo.raid_disks);
>
> --
> 2.31.1
>