Re: [PATCH v2 1/2] md: factor out a new helper to put mddev
From: Song Liu <song@kernel.org>
Date: 2023-09-27 03:00:49
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On Mon, Sep 25, 2023 at 8:04 PM Yu Kuai [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Yu Kuai <redacted> 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 <redacted> --- 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; + } else if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock)) return; +
This condition is indeed very confusing. No matter whether we call the
flag "locked" or "do_lock", it is not really accurate.
How about we factor out a helper with the following logic:
if (!mddev->raid_disks && list_empty(&mddev->disks) &&
mddev->ctime == 0 && !mddev->hold_active) {
/* Array is not configured at all, and not held active,
* so destroy it */
set_bit(MD_DELETED, &mddev->flags);
/*
* Call queue_work inside the spinlock so that
* flush_workqueue() after mddev_find will succeed in waiting
* for the work to be done.
*/
queue_work(md_misc_wq, &mddev->del_work);
}
and then use it at the two callers?
Does this make sense?
Thanks,
Song