Re: [PATCH -next 1/8] md: move initialization and destruction of 'io_acct_set' to md.c

[Xiao Ni <xni@redhat.com>]

On Mon, Jun 19, 2023 at 8:50 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>
> From: Yu Kuai <yukuai3@huawei.com>
>
> 'io_acct_set' is only used for raid0 and raid456, prepare to use it for
> raid1 and raid10, so that io accounting from different levels can be
> consistent.
>
> By the way, follow up patches will also use this io clone mechanism to
> make sure 'active_io' represents in flight io, not io that is dispatching,
> so that mddev_suspend will wait for io to be done as desgined.

Hi Kuai

typo error: s/desgined/designed/g

Before this patch the personality uses ->quiesce method to wait until
all inflight ios come back. But I like this solution. It makes the
codes simpler. Not sure if it can cause problems because it changes
the meaning of ->active_io. I'm doing regression tests to check.

>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
>  drivers/md/md.c    | 27 ++++++++++-----------------
>  drivers/md/md.h    |  2 --
>  drivers/md/raid0.c | 16 ++--------------
>  drivers/md/raid5.c | 41 +++++++++++------------------------------
>  4 files changed, 23 insertions(+), 63 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 8d62f85d2ab0..42347289195a 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -5886,6 +5886,13 @@ int md_run(struct mddev *mddev)
>                         goto exit_bio_set;
>         }
>
> +       if (!bioset_initialized(&mddev->io_acct_set)) {
> +               err = bioset_init(&mddev->io_acct_set, BIO_POOL_SIZE,
> +                                 offsetof(struct md_io_acct, bio_clone), 0);
> +               if (err)
> +                       goto exit_sync_set;
> +       }
> +
>         spin_lock(&pers_lock);
>         pers = find_pers(mddev->level, mddev->clevel);
>         if (!pers || !try_module_get(pers->owner)) {
> @@ -6063,6 +6070,8 @@ int md_run(struct mddev *mddev)
>         module_put(pers->owner);
>         md_bitmap_destroy(mddev);
>  abort:
> +       bioset_exit(&mddev->io_acct_set);
> +exit_sync_set:
>         bioset_exit(&mddev->sync_set);
>  exit_bio_set:
>         bioset_exit(&mddev->bio_set);
> @@ -6286,6 +6295,7 @@ static void __md_stop(struct mddev *mddev)
>         percpu_ref_exit(&mddev->active_io);
>         bioset_exit(&mddev->bio_set);
>         bioset_exit(&mddev->sync_set);
> +       bioset_exit(&mddev->io_acct_set);
>  }
>
>  void md_stop(struct mddev *mddev)
> @@ -8651,23 +8661,6 @@ void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
>  }
>  EXPORT_SYMBOL_GPL(md_submit_discard_bio);
>
> -int acct_bioset_init(struct mddev *mddev)
> -{
> -       int err = 0;
> -
> -       if (!bioset_initialized(&mddev->io_acct_set))
> -               err = bioset_init(&mddev->io_acct_set, BIO_POOL_SIZE,
> -                       offsetof(struct md_io_acct, bio_clone), 0);
> -       return err;
> -}
> -EXPORT_SYMBOL_GPL(acct_bioset_init);
> -
> -void acct_bioset_exit(struct mddev *mddev)
> -{
> -       bioset_exit(&mddev->io_acct_set);
> -}
> -EXPORT_SYMBOL_GPL(acct_bioset_exit);
> -
>  static void md_end_io_acct(struct bio *bio)
>  {
>         struct md_io_acct *md_io_acct = bio->bi_private;
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 7cab9c7c45b8..11299d94b239 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -776,8 +776,6 @@ extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
>  extern void md_finish_reshape(struct mddev *mddev);
>  void md_submit_discard_bio(struct mddev *mddev, struct md_rdev *rdev,
>                         struct bio *bio, sector_t start, sector_t size);
> -int acct_bioset_init(struct mddev *mddev);
> -void acct_bioset_exit(struct mddev *mddev);
>  void md_account_bio(struct mddev *mddev, struct bio **bio);
>
>  extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio);
> diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
> index f8ee9a95e25d..38d9209cada1 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -365,7 +365,6 @@ static void raid0_free(struct mddev *mddev, void *priv)
>         struct r0conf *conf = priv;
>
>         free_conf(mddev, conf);
> -       acct_bioset_exit(mddev);
>  }
>
>  static int raid0_run(struct mddev *mddev)
> @@ -380,16 +379,11 @@ static int raid0_run(struct mddev *mddev)
>         if (md_check_no_bitmap(mddev))
>                 return -EINVAL;
>
> -       if (acct_bioset_init(mddev)) {
> -               pr_err("md/raid0:%s: alloc acct bioset failed.\n", mdname(mddev));
> -               return -ENOMEM;
> -       }
> -
>         /* if private is not null, we are here after takeover */
>         if (mddev->private == NULL) {
>                 ret = create_strip_zones(mddev, &conf);
>                 if (ret < 0)
> -                       goto exit_acct_set;
> +                       return ret;
>                 mddev->private = conf;
>         }
>         conf = mddev->private;
> @@ -420,15 +414,9 @@ static int raid0_run(struct mddev *mddev)
>
>         ret = md_integrity_register(mddev);
>         if (ret)
> -               goto free;
> +               free_conf(mddev, conf);
>
>         return ret;
> -
> -free:
> -       free_conf(mddev, conf);
> -exit_acct_set:
> -       acct_bioset_exit(mddev);
> -       return ret;
>  }
>
>  static void raid0_handle_discard(struct mddev *mddev, struct bio *bio)
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index f8bc74e16811..29cf5455d7a5 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -7787,19 +7787,12 @@ static int raid5_run(struct mddev *mddev)
>         struct md_rdev *rdev;
>         struct md_rdev *journal_dev = NULL;
>         sector_t reshape_offset = 0;
> -       int i, ret = 0;
> +       int i;
>         long long min_offset_diff = 0;
>         int first = 1;
>
> -       if (acct_bioset_init(mddev)) {
> -               pr_err("md/raid456:%s: alloc acct bioset failed.\n", mdname(mddev));
> +       if (mddev_init_writes_pending(mddev) < 0)
>                 return -ENOMEM;
> -       }
> -
> -       if (mddev_init_writes_pending(mddev) < 0) {
> -               ret = -ENOMEM;
> -               goto exit_acct_set;
> -       }
>
>         if (mddev->recovery_cp != MaxSector)
>                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
> @@ -7830,8 +7823,7 @@ static int raid5_run(struct mddev *mddev)
>             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
>                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
>                           mdname(mddev));
> -               ret = -EINVAL;
> -               goto exit_acct_set;
> +               return -EINVAL;
>         }
>
>         if (mddev->reshape_position != MaxSector) {
> @@ -7856,15 +7848,13 @@ static int raid5_run(struct mddev *mddev)
>                 if (journal_dev) {
>                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
>                                 mdname(mddev));
> -                       ret = -EINVAL;
> -                       goto exit_acct_set;
> +                       return -EINVAL;
>                 }
>
>                 if (mddev->new_level != mddev->level) {
>                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
>                                 mdname(mddev));
> -                       ret = -EINVAL;
> -                       goto exit_acct_set;
> +                       return -EINVAL;
>                 }
>                 old_disks = mddev->raid_disks - mddev->delta_disks;
>                 /* reshape_position must be on a new-stripe boundary, and one
> @@ -7880,8 +7870,7 @@ static int raid5_run(struct mddev *mddev)
>                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
>                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
>                                 mdname(mddev));
> -                       ret = -EINVAL;
> -                       goto exit_acct_set;
> +                       return -EINVAL;
>                 }
>                 reshape_offset = here_new * chunk_sectors;
>                 /* here_new is the stripe we will write to */
> @@ -7903,8 +7892,7 @@ static int raid5_run(struct mddev *mddev)
>                         else if (mddev->ro == 0) {
>                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
>                                         mdname(mddev));
> -                               ret = -EINVAL;
> -                               goto exit_acct_set;
> +                               return -EINVAL;
>                         }
>                 } else if (mddev->reshape_backwards
>                     ? (here_new * chunk_sectors + min_offset_diff <=
> @@ -7914,8 +7902,7 @@ static int raid5_run(struct mddev *mddev)
>                         /* Reading from the same stripe as writing to - bad */
>                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
>                                 mdname(mddev));
> -                       ret = -EINVAL;
> -                       goto exit_acct_set;
> +                       return -EINVAL;
>                 }
>                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
>                 /* OK, we should be able to continue; */
> @@ -7939,10 +7926,8 @@ static int raid5_run(struct mddev *mddev)
>         else
>                 conf = mddev->private;
>
> -       if (IS_ERR(conf)) {
> -               ret = PTR_ERR(conf);
> -               goto exit_acct_set;
> -       }
> +       if (IS_ERR(conf))
> +               return PTR_ERR(conf);
>
>         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
>                 if (!journal_dev) {
> @@ -8140,10 +8125,7 @@ static int raid5_run(struct mddev *mddev)
>         free_conf(conf);
>         mddev->private = NULL;
>         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
> -       ret = -EIO;
> -exit_acct_set:
> -       acct_bioset_exit(mddev);
> -       return ret;
> +       return -EIO;
>  }
>
>  static void raid5_free(struct mddev *mddev, void *priv)
> @@ -8151,7 +8133,6 @@ static void raid5_free(struct mddev *mddev, void *priv)
>         struct r5conf *conf = priv;
>
>         free_conf(conf);
> -       acct_bioset_exit(mddev);
>         mddev->to_remove = &raid5_attrs_group;
>  }
>
> --
> 2.39.2
>

The patch is good for me.

Reviewed-by: Xiao Ni <xni@redhat.com>