Re: [PATCH v4] nvmet: force reconnect when number of queue changes

[Chaitanya Kulkarni <chaitanyak@nvidia.com>]

On 10/25/2022 8:50 AM, Daniel Wagner wrote:
> In order to test queue number changes we need to make sure that the
> host reconnects. Because only when the host disconnects from the
> target the number of queues are allowed to change according the spec.
> 
> The initial idea was to disable and re-enable the ports and have the
> host wait until the KATO timer expires, triggering error
> recovery. Though the host would see a DNR reply when trying to
> reconnect. Because of the DNR bit the connection is dropped
> completely. There is no point in trying to reconnect with the same
> parameters according the spec.
> 
> We can force to reconnect the host is by deleting all controllers. The
> host will observe any newly posted request to fail and thus starts the
> error recovery but this time without the DNR bit set.
> 

Without looking into the spec, isn't some sort of AEN should be used for
this ? please correct me if I'm wrong but deleting all the controllers 
and relaying on reconnect maybe overkill ? if it doesn't exists in
the NVMe spec then perhaps we should think/work on it to update the
spec ? Is it worth it ?

> Reviewed-by: Hannes Reinecke <hare@suse.de>
> Acked-by: Sagi Grimberg <sagi@grimberg.me>
> Signed-off-by: Daniel Wagner <dwagner@suse.de>
> ---


Reviewed-by: Chaitanya Kulkarni  <kch@nvidia.com>

-ck