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Date:   Tue, 21 Apr 2020 09:55:33 -0400
From:   Dan Schatzberg <schatzberg.dan@gmail.com>
To:     Hillf Danton <hdanton@sina.com>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/4] loop: Use worker per cgroup instead of kworker
Message-ID: <20200421135533.GA9623@dschatzberg-fedora-PC0Y6AEN>
References: <20200420223936.6773-1-schatzberg.dan@gmail.com>
 <20200421024845.6948-1-hdanton@sina.com>
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On Tue, Apr 21, 2020 at 10:48:45AM +0800, Hillf Danton wrote:
> 
> On Mon, 20 Apr 2020 18:39:29 -0400 Dan Schatzberg wrote:
> > 
> > @@ -1140,8 +1215,17 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
> >  	blk_mq_freeze_queue(lo->lo_queue);
> >  
> >  	spin_lock_irq(&lo->lo_lock);
> > +	destroy_workqueue(lo->workqueue);
> 
> Destruct it out of atomic context.

I may as well do this, but it doesn't matter, does it? The
blk_mq_freeze_queue above should drain all I/O so the workqueue will
be idle.