Re: [PATCH v3 3/3] scsi: ufs: Fix wrong Task Tag used in task management request UPIUs

[Bart Van Assche <bvanassche@acm.org>]

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.