Re: [PATCH v2 2/5] nvme-fc: do not retry when auth fails or connection is refused

[Hannes Reinecke]

On 2/21/24 17:37, Daniel Wagner wrote:
> On Wed, Feb 21, 2024 at 04:53:44PM +0100, Hannes Reinecke wrote:
> > On 2/21/24 14:24, Daniel Wagner wrote:
> > > There is no point in retrying to connect if the authentication fails.
> > >
> > > Connection refused is also issued from the authentication path, thus
> > > also do not retry.
> > >
> > > Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> > > Signed-off-by: Daniel Wagner <dwagner@xxxxxxx>
> > > ---
> > >    drivers/nvme/host/fc.c | 2 ++
> > >    1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> > > index a5b29e9ad342..b81046c9f171 100644
> > > --- a/drivers/nvme/host/fc.c
> > > +++ b/drivers/nvme/host/fc.c
> > > @@ -3312,6 +3312,8 @@ nvme_fc_reconnect_or_delete(struct nvme_fc_ctrl *ctrl, int status)
> > >    			ctrl->cnum, status);
> > >    		if (status > 0 && (status & NVME_SC_DNR))
> > >    			recon = false;
> > > +		if (status == NVME_SC_AUTH_REQUIRED || status == -ECONNREFUSED)
> > > +			recon = false;
> > >    	} else if (time_after_eq(jiffies, rport->dev_loss_end))
> > >    		recon = false;
> > Is this still required after the patchset to retry authentication errors?
>
> Do you mean
>
>    48dae46676d1 ("nvme: enable retries for authentication commands")
>
> ?
Yes.

> In this case yes, I've tested on top of this patch. This breaks the loop
> where the provided key is invalid or is missing. The loop would happy
> retry until reaching max of retries.

But that's to be expected, no? After all, that's _precisely_ what 
NVME_SC_DNR is for; if you shouldn't retry, that bit is set.
If it's not set, you should.
So why is NVME_SC_AUTH_REQUIRED an exception?

Cheers,

Hannes
--
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@xxxxxxx                                +49 911 74053 688
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