> 2014-09-10 20:54 GMT+09:00 Dolev Raviv <dra...@codeaurora.org>:
>> +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.
Thanks,
Dolev
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