Re: [PATCH v6.1] md: move initialization and destruction of 'io_acct_set' to md.c

Salvatore Bonaccorso
2025-05-06T19:16:57Z

Hi,

On Tue, May 06, 2025 at 09:24:17AM +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
>
> commit c567c86b90d4715081adfe5eb812141a5b6b4883 upstream.
>
> '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 designed.
>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> Reviewed-by: Xiao Ni <xni@redhat.com>
> Signed-off-by: Song Liu <song@kernel.org>
> Link: https://lore.kernel.org/r/20230621165110.1498313-2-yukuai1@huaweicloud.com
> [Yu Kuai: This is the relied patch for commit 4a05f7ae3371 ("md/raid10:
> fix missing discard IO accounting"), kernel will panic while issuing
> discard to raid10 without this patch]
> 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 d5fbccc72810..a9fcfcbc2d11 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -5965,6 +5965,13 @@ 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)) {
> @@ -6142,6 +6149,8 @@ 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);
> @@ -6374,6 +6383,7 @@ 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)
> @@ -8744,23 +8754,6 @@ 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 4f0b48097455..1fda5e139beb 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -746,8 +746,6 @@ 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 7c6a0b4437d8..c50a7abda744 100644
> --- a/drivers/md/raid0.c
> +++ b/drivers/md/raid0.c
> @@ -377,7 +377,6 @@ 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)
> @@ -392,16 +391,11 @@ 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;
> @@ -432,15 +426,9 @@ 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;
> }
>
> /*
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 4315dabd3202..6e80a439ec45 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -7770,19 +7770,12 @@ 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",
> @@ -7813,8 +7806,7 @@ 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) {
> @@ -7839,15 +7831,13 @@ 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
> @@ -7863,8 +7853,7 @@ 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 */
> @@ -7886,8 +7875,7 @@ 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 <=
> @@ -7897,8 +7885,7 @@ 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; */
> @@ -7922,10 +7909,8 @@ 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) {
> @@ -8125,10 +8110,7 @@ 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)
> @@ -8136,7 +8118,6 @@ 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

FWIW, this was tested for people in Debian affected by
https://bugs.debian.org/1104460 .

Regards,
Salvatore