[RFC v2 2/3] nvme: add error logging opt-in

[alan.adamson at oracle.com]

On 3/28/23 11:37 PM, Sagi Grimberg wrote:
>
>>>> Commit d7ac8dca938c ("nvme: quiet user passthrough command errors") 
>>>> disabled error
>>>> logging for user passthrough commands.  This commit adds the 
>>>> ability to opt-in
>>>> to passthrough error logging.
>>>>
>>>> To enable passthrough error logging:
>>>>          echo 1 > /sys/kernel/debug/nvme0/error-logging
>>>>
>>>> To disable passthrough error logging:
>>>>          echo 0 > /sys/kernel/debug/nvme0/error-logging
>>>>
>>>> By default, passthrough error logging will remain disabled.
>>>>
>>>> CONFIG_NVME_ERROR_LOGGING_DEBUG_FS needs to be enabled to
>>>> to enable passthrough error logging.
>>> Any reason to do this in debugfs vs sysfs which is someting
>>> that we can a handle too much more easily?
>>>
>>> Also why do we need a config option for a trivial mount of code?
>>>
>> Putting it in sysfs may make more sense and not require debugfs to be 
>> configured.  See below.
>>
>> Alan
>>
>>
>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>> index 53ef028596c6..24b4dcbfe819 100644
>> --- a/drivers/nvme/host/core.c
>> +++ b/drivers/nvme/host/core.c
>> @@ -337,6 +337,49 @@ static void nvme_log_error(struct request *req)
>>                  nr->status & NVME_SC_DNR  ? "DNR "  : "");
>>   }
>>
>> +static void nvme_log_error_passthrough(struct request *req)
>> +{
>> +    struct nvme_ns *ns = req->q->queuedata;
>> +    struct nvme_request *nr = nvme_req(req);
>> +
>> +    if (ns) {
>> +        pr_err_ratelimited("%s: %s(0x%x), %s (sct 0x%x / sc 0x%x) 
>> %s%s: "
>> +               "cdw10=0x%x cdw11=0x%x cdw12=0x%x cdw13=0x%x 
>> cdw14=0x%x cdw15=0x%x\n",
>> +               ns->disk ? ns->disk->disk_name : "?",
>> + nvme_get_opcode_str(nr->cmd->common.opcode),
>> +               nr->cmd->common.opcode,
>> +               nvme_get_error_status_str(nr->status),
>> +               nr->status >> 8 & 7,    /* Status Code Type */
>> +               nr->status & 0xff,    /* Status Code */
>> +               nr->status & NVME_SC_MORE ? "MORE " : "",
>> +               nr->status & NVME_SC_DNR  ? "DNR "  : "",
>> +               nr->cmd->common.cdw10,
>> +               nr->cmd->common.cdw11,
>> +               nr->cmd->common.cdw12,
>> +               nr->cmd->common.cdw13,
>> +               nr->cmd->common.cdw14,
>> +               nr->cmd->common.cdw15);
>> +        return;
>> +    }
>> +
>> +    pr_err_ratelimited("%s: %s(0x%x), %s (sct 0x%x / sc 0x%x) %s%s: "
>> +               "cdw10=0x%x cdw11=0x%x cdw12=0x%x cdw13=0x%x 
>> cdw14=0x%x cdw15=0x%x\n",
>> +               dev_name(nr->ctrl->device),
>> + nvme_get_admin_opcode_str(nr->cmd->common.opcode),
>> +               nr->cmd->common.opcode,
>> +               nvme_get_error_status_str(nr->status),
>> +               nr->status >> 8 & 7,    /* Status Code Type */
>> +               nr->status & 0xff,    /* Status Code */
>> +               nr->status & NVME_SC_MORE ? "MORE " : "",
>> +               nr->status & NVME_SC_DNR  ? "DNR "  : "",
>> +                   nr->cmd->common.cdw10,
>> +                   nr->cmd->common.cdw11,
>> +                   nr->cmd->common.cdw12,
>> +                   nr->cmd->common.cdw13,
>> +                   nr->cmd->common.cdw14,
>> +                   nr->cmd->common.cdw15);
>> +}
>> +
>>   enum nvme_disposition {
>>       COMPLETE,
>>       RETRY,
>> @@ -381,8 +424,12 @@ static inline void nvme_end_req(struct request 
>> *req)
>>   {
>>       blk_status_t status = nvme_error_status(nvme_req(req)->status);
>>
>> -    if (unlikely(nvme_req(req)->status && !(req->rq_flags & 
>> RQF_QUIET)))
>> -        nvme_log_error(req);
>> +    if (unlikely(nvme_req(req)->status && !(req->rq_flags & 
>> RQF_QUIET))) {
>> +        if (blk_rq_is_passthrough(req))
>> +            nvme_log_error_passthrough(req);
>> +        else
>> +            nvme_log_error(req);
>> +    }
>>       nvme_end_req_zoned(req);
>>       nvme_trace_bio_complete(req);
>>       if (req->cmd_flags & REQ_NVME_MPATH)
>> @@ -666,6 +713,8 @@ static inline void nvme_clear_nvme_request(struct 
>> request *req)
>>   /* initialize a passthrough request */
>>   void nvme_init_request(struct request *req, struct nvme_command *cmd)
>>   {
>> +    struct nvme_request *nr = nvme_req(req);
>> +
>>       if (req->q->queuedata)
>>           req->timeout = NVME_IO_TIMEOUT;
>>       else /* no queuedata implies admin queue */
>> @@ -678,8 +727,10 @@ void nvme_init_request(struct request *req, 
>> struct nvme_command *cmd)
>>       if (req->mq_hctx->type == HCTX_TYPE_POLL)
>>           req->cmd_flags |= REQ_POLLED;
>>       nvme_clear_nvme_request(req);
>> -    req->rq_flags |= RQF_QUIET;
>> -    memcpy(nvme_req(req)->cmd, cmd, sizeof(*cmd));
>> +    if (!nr->ctrl->error_logging)
>> +        req->rq_flags |= RQF_QUIET;
>> +
>> +    memcpy(nr->cmd, cmd, sizeof(*cmd));
>>   }
>>   EXPORT_SYMBOL_GPL(nvme_init_request);
>>
>> @@ -3418,6 +3469,37 @@ static ssize_t nvme_sysfs_rescan(struct device 
>> *dev,
>>   }
>>   static DEVICE_ATTR(rescan_controller, S_IWUSR, NULL, 
>> nvme_sysfs_rescan);
>>
>> +static ssize_t nvme_passthrough_show(struct device *dev,
>> +        struct device_attribute *attr, char *buf)
>> +{
>> +    struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
>> +
>> +    if (ctrl->error_logging)
>> +        return sysfs_emit(buf, "on\n");
>> +    else
>> +        return sysfs_emit(buf, "off\n");
>> +}
>> +
>> +static ssize_t nvme_passthrough_store(struct device *dev,
>> +        struct device_attribute *attr, const char *buf, size_t count)
>> +{
>> +    struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
>> +    int passthrough_enable, err;
>> +
>> +    err = kstrtoint(buf, 10, &passthrough_enable);
>> +    if (err)
>> +        return -EINVAL;
>> +
>> +    if (passthrough_enable)
>> +        ctrl->error_logging = true;
>> +    else
>> +        ctrl->error_logging = false;
>> +
>> +    return count;
>> +}
>> +
>> +static DEVICE_ATTR(passthrough_logging, S_IRUGO | S_IWUSR, 
>> nvme_passthrough_show, nvme_passthrough_store);
>
> Is this something that we need per ctrl? My assumption is that
> if someone wants this, one would enable it for all controllers.
> Maybe this should be a modparam instead?

Maybe both?  Have the ability to set the system-wide default value via 
modparam and sysfs to change it per ctrl?


Alan