linux-kernel - Re: [PATCH V5 0/2] nvme-pci: fix the timeout case when reset is ongoing

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Message-ID: <3cc0d180-0b7e-e71f-66ce-43f4dfffb701@oracle.com>
Date:   Fri, 19 Jan 2018 21:56:48 +0800
From:   "jianchao.wang" <jianchao.w.wang@...cle.com>
To:     Keith Busch <keith.busch@...el.com>
Cc:     axboe@...com, hch@....de, sagi@...mberg.me, maxg@...lanox.com,
        james.smart@...adcom.com, linux-nvme@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V5 0/2] nvme-pci: fix the timeout case when reset is
 ongoing

Hi Keith

Thanks for your kindly response.

On 01/19/2018 07:52 PM, Keith Busch wrote:
> On Fri, Jan 19, 2018 at 05:02:06PM +0800, jianchao.wang wrote:
>> We should not use blk_sync_queue here, the requeue_work and run_work will be canceled.
>> Just flush_work(&q->timeout_work) should be ok.
> 
> I agree flushing timeout_work is sufficient. All the other work had
> already better not be running either, so it doesn't hurt to call the
> sync API.
In nvme_dev_disable, the outstanding requests will be requeued finally.
I'm afraid the requests requeued on the q->requeue_list will be blocked until another requeue
occurs, if we cancel the requeue work before it get scheduled.

>  
>> In addition, we could check NVME_CC_ENABLE in nvme_dev_disable to avoid redundant invoking.
>> :)
> 
> That should already be inferred through reading back the CSTS register.
> 
Yes, the "dead"  in nvme_dev_disable looks enough for these uncommon cases.

Thanks
Jianchao