Re: [PATCH] md: raid0: account for split bio in iostat accounting

[Laurence Oberman <loberman@xxxxxxxxxx>]

On Wed, 2023-08-09 at 13:16 -0400, David Jeffery wrote:
> When a bio is split by md raid0, the newly created bio will not be
> tracked
> by md for I/O accounting. Only the portion of I/O still assigned to
> the
> original bio which was reduced by the split will be accounted for.
> This
> results in md iostat data sometimes showing I/O values far below the
> actual
> amount of data being sent through md.
> 
> md_account_bio() needs to be called for all bio generated by the bio
> split.
> 
> Signed-off-by: David Jeffery <djeffery@xxxxxxxxxx>
> Tested-by: Laurence Oberman <loberman@xxxxxxxxxx>
> ---
>  drivers/md/raid0.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index d1ac73fcd852..1fd559ac8c68 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -597,8 +597,7 @@ static bool raid0_make_request(struct mddev
> *mddev, struct bio *bio)
>                 bio = split;
>         }
>  
> -       if (bio->bi_pool != &mddev->bio_set)
> -               md_account_bio(mddev, &bio);
> +       md_account_bio(mddev, &bio);
>  
>         orig_sector = sector;
>         zone = find_zone(mddev->private, &sector);

Works well, looks good.
Reviewed-by: Laurence Oberman <loberman@xxxxxxxxxx>