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Date:   Fri, 2 Feb 2018 11:46:05 -0700
From:   Keith Busch <keith.busch@intel.com>
To:     Jianchao Wang <jianchao.w.wang@oracle.com>
Cc:     axboe@fb.com, hch@lst.de, sagi@grimberg.me,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/6] nvme-pci: move clearing host mem behind stopping
 queues
Message-ID: <20180202184605.GJ24417@localhost.localdomain>
References: <1517554849-7802-1-git-send-email-jianchao.w.wang@oracle.com>
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On Fri, Feb 02, 2018 at 03:00:44PM +0800, Jianchao Wang wrote:
> Move clearing host mem behind stopping queues. Prepare for
> following patch which will grab all the outstanding requests.
> 
> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>

This one makes sense, though I would alter the change log to something
like:

  This patch quiecses new IO prior to disabling device HMB access.
  A controller using HMB may be relying on it to efficiently complete
  IO commands.

Reviewed-by: Keith Busch <keith.busch@intel.com>

> ---
>  drivers/nvme/host/pci.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 6fe7af0..00cffed 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2186,7 +2186,10 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
>  	if (!dead) {
>  		if (shutdown)
>  			nvme_wait_freeze_timeout(&dev->ctrl, NVME_IO_TIMEOUT);
> +	}
> +	nvme_stop_queues(&dev->ctrl);
>  
> +	if (!dead) {
>  		/*
>  		 * If the controller is still alive tell it to stop using the
>  		 * host memory buffer.  In theory the shutdown / reset should
> @@ -2195,11 +2198,6 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
>  		 */
>  		if (dev->host_mem_descs)
>  			nvme_set_host_mem(dev, 0);
> -
> -	}
> -	nvme_stop_queues(&dev->ctrl);
> -
> -	if (!dead) {
>  		nvme_disable_io_queues(dev);
>  		nvme_disable_admin_queue(dev, shutdown);
>  	}
> -- 
> 2.7.4