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Date:   Mon, 25 Jul 2022 09:35:17 -0700
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Subject: Re: [PATCH 1/2] scsi: ufs: Add Multi-Circular Queue support
To:     Avri Altman <Avri.Altman@wdc.com>, Can Guo <quic_cang@quicinc.com>,
        "bvanassche@acm.org" <bvanassche@acm.org>,
        "stanley.chu@mediatek.com" <stanley.chu@mediatek.com>,
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        "beanhuo@micron.com" <beanhuo@micron.com>,
        "quic_nguyenb@quicinc.com" <quic_nguyenb@quicinc.com>,
        "quic_ziqichen@quicinc.com" <quic_ziqichen@quicinc.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "kernel-team@android.com" <kernel-team@android.com>
CC:     "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Daejun Park <daejun7.park@samsung.com>,
        Jinyoung Choi <j-young.choi@samsung.com>,
        Kiwoong Kim <kwmad.kim@samsung.com>,
        open list <linux-kernel@vger.kernel.org>
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From:   "Asutosh Das (asd)" <quic_asutoshd@quicinc.com>
In-Reply-To: <DM6PR04MB65756C5A6C5F674B19091F7DFC939@DM6PR04MB6575.namprd04.prod.outlook.com>
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On 7/23/2022 2:23 PM, Avri Altman wrote:
>>   static inline
>> -void ufshcd_send_command(struct ufs_hba *hba, unsigned int task_tag)
>> +void ufshcd_send_command(struct ufs_hba *hba, struct ufshcd_lrb *lrbp,
>> +                        struct ufs_hw_queue *hwq)
>>   {
>> -       struct ufshcd_lrb *lrbp = &hba->lrb[task_tag];
>>          unsigned long flags;
>>
>>          lrbp->issue_time_stamp = ktime_get();
>>          lrbp->compl_time_stamp = ktime_set(0, 0);
>> -       ufshcd_add_command_trace(hba, task_tag, UFS_CMD_SEND);
>> +       ufshcd_add_command_trace(hba, lrbp, UFS_CMD_SEND);
>>          ufshcd_clk_scaling_start_busy(hba);
>>          if (unlikely(ufshcd_should_inform_monitor(hba, lrbp)))
>>                  ufshcd_start_monitor(hba, lrbp);
>>
>> -       spin_lock_irqsave(&hba->outstanding_lock, flags);
>> -       if (hba->vops && hba->vops->setup_xfer_req)
>> -               hba->vops->setup_xfer_req(hba, task_tag, !!lrbp->cmd);
>> -       __set_bit(task_tag, &hba->outstanding_reqs);
>> -       ufshcd_writel(hba, 1 << task_tag,
>> REG_UTP_TRANSFER_REQ_DOOR_BELL);
>> -       spin_unlock_irqrestore(&hba->outstanding_lock, flags);
>> +       if (is_mcq_enabled(hba)) {
>> +               int utrd_size = sizeof(struct utp_transfer_req_desc);
> Maybe we can map some designated ops, so all those if (is_mcq) can be avoided in the data-path.
Umm, I couldn't find any ops in scsi_host_template {...}. Do you have 
any further insight into how this check can be avoided?
> Also maybe we can constify sizeof(struct utp_transfer_req_desc) which is used now few times.
> 
Ok, agree to make sizeof(struct utp_transfer_req_desc) a constant in the 
next version.

-asd