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

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Date: Fri, 23 Feb 2024 12:58:53 +0100
From: Hannes Reinecke <hare@...e.de>
To: Daniel Wagner <dwagner@...e.de>
Cc: James Smart <james.smart@...adcom.com>, Keith Busch <kbusch@...nel.org>,
 Christoph Hellwig <hch@....de>, Sagi Grimberg <sagi@...mberg.me>,
 linux-nvme@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/5] nvme-fc: do not retry when auth fails or
 connection is refused

On 2/22/24 18:02, Daniel Wagner wrote:
> On Thu, Feb 22, 2024 at 08:45:04AM +0100, Daniel Wagner wrote:
>> On Thu, Feb 22, 2024 at 07:46:12AM +0100, Hannes Reinecke wrote:
>>> On 2/21/24 17:37, Daniel Wagner wrote:
>>>> On Wed, Feb 21, 2024 at 04:53:44PM +0100, Hannes Reinecke wrote:
>>>> 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?
>>
>> Why? If the key is wrong/missing it will be likely wrong/missing the
>> next retry again. So what's the point in retrying?
>>
>>> 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.
>>
>> Okay, in this case there is a bug in the auth code somewhere.
> 
> With the change below nvme/041 also passes:
> 
> modified   drivers/nvme/host/fabrics.c
> @@ -467,7 +467,7 @@ int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl)
>   		if (result & NVME_CONNECT_AUTHREQ_ASCR) {
>   			dev_warn(ctrl->device,
>   				 "qid 0: secure concatenation is not supported\n");
> -			ret = NVME_SC_AUTH_REQUIRED;
> +			ret = NVME_SC_AUTH_REQUIRED | NVME_SC_DNR;
>   			goto out_free_data;
>   		}
>   		/* Authentication required */
> @@ -475,7 +475,7 @@ int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl)
>   		if (ret) {
>   			dev_warn(ctrl->device,
>   				 "qid 0: authentication setup failed\n");
> -			ret = NVME_SC_AUTH_REQUIRED;
> +			ret = NVME_SC_AUTH_REQUIRED | NVME_SC_DNR;
>   			goto out_free_data;
>   		}
>   		ret = nvme_auth_wait(ctrl, 0);
> @@ -540,8 +540,9 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
>   		/* Secure concatenation is not implemented */
>   		if (result & NVME_CONNECT_AUTHREQ_ASCR) {
>   			dev_warn(ctrl->device,
> -				 "qid 0: secure concatenation is not supported\n");
> -			ret = NVME_SC_AUTH_REQUIRED;
> +				 "qid %d: secure concatenation is not supported\n",
> +				 qid);
> +			ret = NVME_SC_AUTH_REQUIRED | NVME_SC_DNR;
>   			goto out_free_data;
>   		}
>   		/* Authentication required */
> @@ -549,7 +550,7 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
>   		if (ret) {
>   			dev_warn(ctrl->device,
>   				 "qid %d: authentication setup failed\n", qid);
> -			ret = NVME_SC_AUTH_REQUIRED;
> +			ret = NVME_SC_AUTH_REQUIRED | NVME_SC_DNR;
>   		} else {
>   			ret = nvme_auth_wait(ctrl, qid);
>   			if (ret)
> 
> Is this what you had in mind?

Which, incidentally, is basically the patch I just posted.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@...e.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich