[PATCHv3] nvme: Return BLK_STS_TARGET if the DNR bit is set

[hare@suse.de (Hannes Reinecke)]

On 8/13/19 6:37 PM, Sagi Grimberg wrote:
> 
>> We need to override the default nvme_error_status() to BLK_STS_TARGET
>> when DNR is set to prevent upper layers from their own retries/failover.
>> I suggested adding that check in the existing unlikely() case, but maybe
>> it's more obvious if we teach nvme_error_status() to default to return
>> BLK_STS_TARGET for this condition?
>>
>> ---
>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>> index 8f3fbe5ca937..50adcdde44d5 100644
>> --- a/drivers/nvme/host/core.c
>> +++ b/drivers/nvme/host/core.c
>> @@ -199,6 +199,9 @@ static inline bool nvme_ns_has_pi(struct nvme_ns *ns)
>> ? static blk_status_t nvme_error_status(struct request *req)
>> ? {
>> +??? if (unlikely(nvme_req(req)->status & NVME_SC_DNR))
>> +??????? return BLK_STS_TARGET;
>> +
>> ????? switch (nvme_req(req)->status & 0x7ff) {
>> ????? case NVME_SC_SUCCESS:
>> ????????? return BLK_STS_OK;
>> -- 
> 
> Makes sense to me, Hannes does this address your issue?
Oh, yes, it does.
I was slightly worried as we would override other non-retryable status 
codes, but as there is no definite mapping which status codes are 
retryable we can go with this one.

I'll be sending a patch.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke            Teamlead Storage & Networking
hare at suse.de                              +49 911 74053 688
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