On Tue, 26 Sep 2023 10:58:26 +0800
Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> There are no functional changes, the new helper will still hold
> 'all_mddevs_lock' after putting mddev, and it will be used to simplify
> md_seq_ops.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> ---
> drivers/md/md.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 10cb4dfbf4ae..a5ef6f7da8ec 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -616,10 +616,15 @@ static inline struct mddev *mddev_get(struct mddev
> *mddev)
> static void mddev_delayed_delete(struct work_struct *ws);
>
> -void mddev_put(struct mddev *mddev)
> +static void __mddev_put(struct mddev *mddev, bool locked)
> {
> - if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
> + if (locked) {
> + spin_lock(&all_mddevs_lock);
> + if (!atomic_dec_and_test(&mddev->active))
> + return;
It is "locked" and we are taking lock? It seems weird to me. Perhaps "do_lock"
would be better? Do you meant "lockdep_assert_held(&all_mddevs_lock);"
Something is wrong here, we have two paths and in both cases we are
taking lock.
> + } else if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock))
> return;
> +
> if (!mddev->raid_disks && list_empty(&mddev->disks) &&
> mddev->ctime == 0 && !mddev->hold_active) {
> /* Array is not configured at all, and not held active,
> @@ -633,7 +638,14 @@ void mddev_put(struct mddev *mddev)
> */
> queue_work(md_misc_wq, &mddev->del_work);
> }
> - spin_unlock(&all_mddevs_lock);
> +
> + if (!locked)
> + spin_unlock(&all_mddevs_lock);
As above, I'm not sure if it is correct.
Thanks,
Mariusz
