2014-09-15 19:39 GMT+09:00 Dolev Raviv <draviv@xxxxxxxxxxxxxx>:
>
>> 2014-09-10 20:54 GMT+09:00 Dolev Raviv <draviv@xxxxxxxxxxxxxx>:
>>> +static void ufshcd_set_queue_depth(struct scsi_device *sdev)
>>> +{
>>> + int ret = 0;
>>> + u8 lun_qdepth;
>>> + struct ufs_hba *hba;
>>> +
>>> + hba = shost_priv(sdev->host);
>>> +
>>> + lun_qdepth = hba->nutrs;
>>> + ret = ufshcd_read_unit_desc_param(hba,
>>> +
>>> ufshcd_scsi_to_upiu_lun(sdev->lun),
>>> + UNIT_DESC_PARAM_LU_Q_DEPTH,
>>> + &lun_qdepth,
>>> + sizeof(lun_qdepth));
>>> +
>>> + /* Some WLUN doesn't support unit descriptor */
>>> + if (ret == -EOPNOTSUPP)
>>> + lun_qdepth = 1;
>>> + else if (!lun_qdepth)
>>> + /* eventually, we can figure out the real queue depth */
>>> + lun_qdepth = hba->nutrs;
>>> + else
>>> + lun_qdepth = min_t(int, lun_qdepth, hba->nutrs);
>>
>> If ufshcd_read_unit_desc_param() failed and its error code was not
>> -EOPNOTSUPP, lun_qdepth is undefined. In such cases lun_qdepth
>> should be 1?
>
> I'm not sure I follow your concern.
> If this lun does not support command queuing (ret == -EOPNOTSUPP)
> obviously, lun_qdepth should be 1.
> If there was an error and lun_qdepth, was returned as 0, hba->nutrs will
> be our default choice.
> last, even if the query succeed we want to make sure we don't exceed the
> hba->nutrs.
I missed that the local variable lun_qdepth is initialized to
hba->nutrs just before calling ufshcd_read_unit_desc_param(). So what
I said undefined in the last message was just wrong. Thanks for the
clarification.
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
