On 2021/2/24 15:06, Hannes Reinecke wrote:

On 2/24/21 7:42 AM, Chao Leng wrote:

quoted

On 2021/2/23 20:07, Hannes Reinecke wrote:

quoted

Hi all,

one of our customer had been running into a deadlock trying to terminate
outstanding KATO commands during reset.
Looking closer at it, I found that we never actually _track_ if a KATO
command is submitted, so we might happily be sending several KATO commands
to the same controller simultaneously.

Can you explain how can send KATO commands simultaneously?

Sure.
Call nvme_start_keep_alive() on a dead connection.
Just _after_ the KATO request has been sent,
call nvme_start_keep_alive() again.

Call nvme_start_keep_alive() again? why?
Now just nvme_start_ctrl call nvme_start_keep_alive().
The ka_work will be canceled sync before start reconnection.
Did I miss something?

You now have an expired KATO command, and the new KATO command, both are active and sent to the controller.

Cheers,

Hannes

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