Re: [PATCH] nvme-fabrics: fix kato initialization

[Hannes Reinecke <hare@suse.de>]

On 2/20/21 9:41 AM, George, Martin wrote:
> On Fri, 2021-02-19 at 17:42 +0100, Hannes Reinecke wrote:
>> On 2/18/21 11:04 AM, Martin George wrote:
>>> Currently kato is initialized to NVME_DEFAULT_KATO for both
>>> discovery & i/o controllers. This is a problem specifically
>>> for non-persistent discovery controllers since it always ends
>>> up with a non-zero kato value. Fix this by initializing kato
>>> to zero instead, and ensuring various controllers are assigned
>>> appropriate kato values as follows:
>>>
>>> non-persistent controllers  - kato set to zero
>>> persistent controllers      - kato set to NVMF_DEV_DISC_TMO
>>>                                 (or any positive int via nvme-cli)
>>> i/o controllers             - kato set to NVME_DEFAULT_KATO
>>>                                 (or any positive int via nvme-cli)
>>>
>>> Signed-off-by: Martin George <marting@netapp.com>
>>> ---
>>>    drivers/nvme/host/fabrics.c | 5 ++++-
>>>    1 file changed, 4 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/nvme/host/fabrics.c
>>> b/drivers/nvme/host/fabrics.c
>>> index 5dfd806fc2d2..604ab0e5a2ad 100644
>>> --- a/drivers/nvme/host/fabrics.c
>>> +++ b/drivers/nvme/host/fabrics.c
>>> @@ -630,7 +630,7 @@ static int nvmf_parse_options(struct
>>> nvmf_ctrl_options *opts,
>>>        opts->queue_size = NVMF_DEF_QUEUE_SIZE;
>>>        opts->nr_io_queues = num_online_cpus();
>>>        opts->reconnect_delay = NVMF_DEF_RECONNECT_DELAY;
>>> -     opts->kato = NVME_DEFAULT_KATO;
>>> +     opts->kato = 0;
>>>        opts->duplicate_connect = false;
>>>        opts->fast_io_fail_tmo = NVMF_DEF_FAIL_FAST_TMO;
>>>        opts->hdr_digest = false;
>>> @@ -893,6 +893,9 @@ static int nvmf_parse_options(struct
>>> nvmf_ctrl_options *opts,
>>>                opts->nr_write_queues = 0;
>>>                opts->nr_poll_queues = 0;
>>>                opts->duplicate_connect = true;
>>> +     } else {
>>> +             if (!opts->kato)
>>> +                     opts->kato = NVME_DEFAULT_KATO;
>>>        }
>>>        if (ctrl_loss_tmo < 0) {
>>>                opts->max_reconnects = -1;
>>>
>> Can't you merge this with the previous patch 'ensure zero-kato ..'?
>>
> 
> Well, you are right that both the previous patch (i.e. 'ensure zero
> kato for non-persistent controllers') & this current patch are jointly
> required for assigning proper kato values to the various controllers,
> so it would have made sense to merge the two. But the previous one is a
> nvme-cli patch, whereas this current one is a kernel patch. That's why
> I chose to create separate individual patches itself here.
> 
> So I hope this is good enough. If not, please let me know what's the
> right way to proceed here.
> 
Argl. Of course you are correct.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

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