Re: [dm-devel] [PATCH -next v2 2/6] md: refactor action_store() for 'idle' and 'frozen'

From: Xiao Ni <xni@redhat.com>
To: Yu Kuai <yukuai1@huaweicloud.com>
Cc: guoqing.jiang@linux.dev, agk@redhat.com, snitzer@kernel.org,
	dm-devel@redhat.com, song@kernel.org, yi.zhang@huawei.com,
	yangerkun@huawei.com, linux-kernel@vger.kernel.org,
	linux-raid@vger.kernel.org, "yukuai (C)" <yukuai3@huawei.com>
Subject: Re: [dm-devel] [PATCH -next v2 2/6] md: refactor action_store() for 'idle' and 'frozen'
Date: Tue, 13 Jun 2023 20:25:59 +0800	[thread overview]
Message-ID: <CALTww2-ta1NUJxcT3Dq5KP7iunnVx24X7RKj1OKYTYwEPeDNrg@mail.gmail.com> (raw)
In-Reply-To: <1aaf9150-bbd3-87a8-8d54-8b5d63ab5ed3@huaweicloud.com>

On Tue, Jun 13, 2023 at 8:00 PM Yu Kuai <yukuai1@huaweicloud.com> wrote:
>
> Hi,
>
> 在 2023/06/13 16:02, Xiao Ni 写道:
> >
> > 在 2023/5/29 下午9:20, Yu Kuai 写道:
> >> From: Yu Kuai <yukuai3@huawei.com>
> >>
> >> Prepare to handle 'idle' and 'frozen' differently to fix a deadlock,
> >> there
> >> are no functional changes except that MD_RECOVERY_RUNNING is checked
> >> again after 'reconfig_mutex' is held.
> >
> >
> > Can you explain more about why it needs to check MD_RECOVERY_RUNNING
> > again here?
>
> As I explain in the following comment:

Hi

Who can clear the flag before the lock is held?

Regards
Xiao
> >> +    /*
> >> +     * Check again in case MD_RECOVERY_RUNNING is cleared before lock is
> >> +     * held.
> >> +     */
> >> +    if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
> >> +        mddev_unlock(mddev);
> >> +        return;
> >> +    }
>
> Thanks,
> Kuai
>