[PATCH 2/6] nvme-pci: fix the freeze and quiesce for shutdown and reset case

[Keith Busch]

On Thu, Feb 08, 2018 at 10:17:00PM +0800, jianchao.wang wrote:
> There is a dangerous scenario which caused by nvme_wait_freeze in nvme_reset_work.
> please consider it.
> 
> nvme_reset_work
>   -> nvme_start_queues
>   -> nvme_wait_freeze
> 
> if the controller no response, we have to rely on the timeout path.
> there are issues below:
> nvme_dev_disable need to be invoked.
> nvme_dev_disable will quiesce queues, cancel and requeue and outstanding requests.
> nvme_reset_work will hang at nvme_wait_freeze

We used to not requeue timed out commands, so that wasn't a problem
before. Oh well, I'll take a look.