Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v3 3/3] scsi: ufs: Fix wrong Task Tag used in task
 management request UPIUs
To:     Can Guo <cang@codeaurora.org>
Cc:     jaegeuk@kernel.org, asutoshd@codeaurora.org,
        nguyenb@codeaurora.org, hongwus@codeaurora.org,
        linux-scsi@vger.kernel.org, kernel-team@android.com,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Sujit Reddy Thumma <sthumma@codeaurora.org>,
        Vinayak Holikatti <vinholikatti@gmail.com>,
        Yaniv Gardi <ygardi@codeaurora.org>,
        open list <linux-kernel@vger.kernel.org>
References: <1611807365-35513-1-git-send-email-cang@codeaurora.org>
 <1611807365-35513-4-git-send-email-cang@codeaurora.org>
 <8351747f-0ec9-3c66-1bdf-b4b73fcee698@acm.org>
 <f0d1c6a196a044198647df6ca4b06efb@codeaurora.org>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <cd83aa1d-444e-d4ba-c363-517dbf07891a@acm.org>
Date:   Sun, 31 Jan 2021 18:39:19 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.6.1
MIME-Version: 1.0
In-Reply-To: <f0d1c6a196a044198647df6ca4b06efb@codeaurora.org>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 1/28/21 9:57 PM, Can Guo wrote:
> On 2021-01-29 11:15, Bart Van Assche wrote:
>> On 1/27/21 8:16 PM, Can Guo wrote:
>>> In __ufshcd_issue_tm_cmd(), it is not right to use hba->nutrs +
>>> req->tag as
>>> the Task Tag in one TMR UPIU. Directly use req->tag as the Task Tag.
>>
>> Why is the current code wrong and why is this patch the proper fix?
>> Please explain this in the patch description.
> 
> req->tag is the tag allocated for one TMR, no?

Hi Can,
 Commit e293313262d3 ("scsi: ufs: Fix broken task management command
implementation") includes the following changes:

+       task_tag = hba->nutrs + free_slot;
        task_req_upiup->header.dword_0 =
                UPIU_HEADER_DWORD(UPIU_TRANSACTION_TASK_REQ, 0,
-                                            lrbp->lun, lrbp->task_tag);
+                                            lun_id, task_tag);
        task_req_upiup->header.dword_1 =
                UPIU_HEADER_DWORD(0, tm_function, 0, 0);

As one can see the value written in dword_0 starts at hba->nutrs. Was
that code correct? If that code was correct, does your patch perhaps
break task management support?

Thanks,

Bart.