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Subject: Re: [PATCH v4 RFC 14/14] dm-raid: remove mddev_suspend/resume()
To: Yu Kuai <yukuai1@huaweicloud.com>, mpatocka@redhat.com,
 heinzm@redhat.com, xni@redhat.com, agk@redhat.com, snitzer@kernel.org,
 dm-devel@lists.linux.dev, song@kernel.org, jbrassow@f14.redhat.com,
 neilb@suse.de, shli@fb.com, akpm@osdl.org
Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
 yi.zhang@huawei.com, yangerkun@huawei.com, "yukuai (C)" <yukuai3@huawei.com>
References: <20240130021843.3608859-1-yukuai1@huaweicloud.com>
 <20240130021843.3608859-15-yukuai1@huaweicloud.com>
From: Yu Kuai <yukuai1@huaweicloud.com>
Message-ID: <57ec6c2d-f5bb-10fc-39e8-097704daa96c@huaweicloud.com>
Date: Wed, 31 Jan 2024 10:51:38 +0800
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Hi,

?? 2024/01/30 10:18, Yu Kuai д??:
> From: Yu Kuai <yukuai3@huawei.com>
> 
> dm_suspend() already make sure that no new IO can be issued and will
> wait for all dispatched IO to be done. There is no need to call
> mddev_suspend() to make sure that again.
> 

I'm about to send the final version(I hope), please let me know if
anyone thinks this patch should not be included.

Thanks,
Kuai
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
>   drivers/md/dm-raid.c |  8 +++-----
>   drivers/md/md.c      | 11 +++++++++++
>   2 files changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> index 5f78cc19d6f3..ed8c28952b14 100644
> --- a/drivers/md/dm-raid.c
> +++ b/drivers/md/dm-raid.c
> @@ -3241,7 +3241,7 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
>   	rs->md.in_sync = 1;
>   
>   	/* Has to be held on running the array */
> -	mddev_suspend_and_lock_nointr(&rs->md);
> +	mddev_lock_nointr(&rs->md);
>   
>   	/* Keep array frozen until resume. */
>   	md_frozen_sync_thread(&rs->md);
> @@ -3829,11 +3829,9 @@ static void raid_postsuspend(struct dm_target *ti)
>   {
>   	struct raid_set *rs = ti->private;
>   
> -	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags)) {
> +	if (!test_and_set_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
>   		/* Writes have to be stopped before suspending to avoid deadlocks. */
>   		md_stop_writes(&rs->md);
> -		mddev_suspend(&rs->md, false);
> -	}
>   }
>   
>   static void attempt_restore_of_faulty_devices(struct raid_set *rs)
> @@ -4091,7 +4089,7 @@ static void raid_resume(struct dm_target *ti)
>   		mddev->ro = 0;
>   		mddev->in_sync = 0;
>   		md_unfrozen_sync_thread(mddev);
> -		mddev_unlock_and_resume(mddev);
> +		mddev_unlock(mddev);
>   	}
>   }
>   
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 093abf3ce27b..e3a56a958b47 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -437,6 +437,10 @@ int mddev_suspend(struct mddev *mddev, bool interruptible)
>   {
>   	int err = 0;
>   
> +	/* Array is supended from dm_suspend() for dm-raid. */
> +	if (!mddev->gendisk)
> +		return 0;
> +
>   	/*
>   	 * hold reconfig_mutex to wait for normal io will deadlock, because
>   	 * other context can't update super_block, and normal io can rely on
> @@ -488,6 +492,13 @@ EXPORT_SYMBOL_GPL(mddev_suspend);
>   
>   static void __mddev_resume(struct mddev *mddev, bool recovery_needed)
>   {
> +	/*
> +	 * Array is supended from dm_suspend() and resumed from dm_resume() for
> +	 * dm-raid.
> +	 */
> +	if (!mddev->gendisk)
> +		return;
> +
>   	lockdep_assert_not_held(&mddev->reconfig_mutex);
>   
>   	mutex_lock(&mddev->suspend_mutex);
>