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

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Message-ID: <83bca01f-fc34-405b-9f2e-8079130400ce@grimberg.me>
Date: Thu, 7 Mar 2024 12:25:16 +0200
From: Sagi Grimberg <sagi@...mberg.me>
To: Hannes Reinecke <hare@...e.de>, Daniel Wagner <dwagner@...e.de>
Cc: James Smart <james.smart@...adcom.com>, Keith Busch <kbusch@...nel.org>,
 Christoph Hellwig <hch@....de>, 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 23/02/2024 13:58, Hannes Reinecke wrote:
> 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.

Reading this, the patchset from Hannes now is clearer.
Isn't the main issue is that nvme-fc tries to periodicly reconnect
when failing the first connect? This is exactly what the test expects
it to do right?