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Date:   Mon, 5 Feb 2018 08:13:14 -0700
From:   Keith Busch <keith.busch@intel.com>
To:     "jianchao.wang" <jianchao.w.wang@oracle.com>
Cc:     axboe@fb.com, linux-kernel@vger.kernel.org, hch@lst.de,
        linux-nvme@lists.infradead.org, sagi@grimberg.me
Subject: Re: [PATCH 2/6] nvme-pci: fix the freeze and quiesce for shutdown
 and reset case
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On Mon, Feb 05, 2018 at 10:26:03AM +0800, jianchao.wang wrote:
> > Freezing is not just for shutdown. It's also used so
> > blk_mq_update_nr_hw_queues will work if the queue count changes across
> > resets.
> blk_mq_update_nr_hw_queues will freeze the queue itself. Please refer to.
> static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,

Yes, but how many requests are you letting enter to their demise by
freezing on the wrong side of the reset? We don't use the nuclear option
out of convenience.