[PATCH 4/4] nvme: redirect commands on dying queue

[Mike Snitzer]

On Mon, Aug 17 2020 at  4:15am -0400,
Christoph Hellwig <hch at lst.de> wrote:

> From: Chao Leng <lengchao at huawei.com>
> 
> If a command send through nvme-multipath failed on a dying queue, resend it
> on another path.
> 
> Signed-off-by: Chao Leng <lengchao at huawei.com>
> [hch: rebased on top of the completion refactoring]
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Sagi Grimberg <sagi at grimberg.me>

Did we ever learn from Chao what the original issue was?  Deciding to
failover on completion because blk_queue_dying(), without any other
insight, is definitely new to me.

But this looks fine, just in general such blk_queue_dying() checks are
pretty racey right?  Feels like this might paper over something else but
without knowing more:

Reviewed-by: Mike Snitzer <snitzer at redhat.com>