RE: [PATCH v4 2/2] scsi: ufs: Fix wrong Task Tag used in task management request UPIUs

RE: [PATCH v4 2/2] scsi: ufs: Fix wrong Task Tag used in task management request UPIUs

[Daejun Park]

Hi, Can Guo

> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
...
>  
>  	req->end_io_data = &wait;
> -	free_slot = req->tag;
>  	WARN_ON_ONCE(free_slot < 0 || free_slot >= hba->nutmrs);
I think this line should be removed.

Thanks,
Daejun

Re: [PATCH v4 2/2] scsi: ufs: Fix wrong Task Tag used in task management request UPIUs

[Can Guo]

On 2021-04-01 14:44, Daejun Park wrote:
> Hi, Can Guo
> 
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> ...
>> 
>>  	req->end_io_data = &wait;
>> -	free_slot = req->tag;
>>  	WARN_ON_ONCE(free_slot < 0 || free_slot >= hba->nutmrs);
> I think this line should be removed.
> 

Oh, yes, will remove it in next version.

Thanks,
Can Guo.

> Thanks,
> Daejun

[PATCH v4 2/2] scsi: ufs: Fix wrong Task Tag used in task management request UPIUs

[Can Guo]

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.

Fixes: e293313262d3 ("scsi: ufs: Fix broken task management command implementation")

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index d4f8cb2..cdd8c3d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6446,38 +6446,35 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
 	DECLARE_COMPLETION_ONSTACK(wait);
 	struct request *req;
 	unsigned long flags;
-	int free_slot, task_tag, err;
+	int task_tag, err;
 
 	/*
-	 * Get free slot, sleep if slots are unavailable.
-	 * Even though we use wait_event() which sleeps indefinitely,
-	 * the maximum wait time is bounded by %TM_CMD_TIMEOUT.
+	 * blk_get_request() is used here only to get a free tag.
 	 */
 	req = blk_get_request(q, REQ_OP_DRV_OUT, 0);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
 	req->end_io_data = &wait;
-	free_slot = req->tag;
 	WARN_ON_ONCE(free_slot < 0 || free_slot >= hba->nutmrs);
 	ufshcd_hold(hba, false);
 
 	spin_lock_irqsave(host->host_lock, flags);
-	task_tag = hba->nutrs + free_slot;
 	blk_mq_start_request(req);
 
+	task_tag = req->tag;
 	treq->req_header.dword_0 |= cpu_to_be32(task_tag);
 
-	memcpy(hba->utmrdl_base_addr + free_slot, treq, sizeof(*treq));
-	ufshcd_vops_setup_task_mgmt(hba, free_slot, tm_function);
+	memcpy(hba->utmrdl_base_addr + task_tag, treq, sizeof(*treq));
+	ufshcd_vops_setup_task_mgmt(hba, task_tag, tm_function);
 
 	/* send command to the controller */
-	__set_bit(free_slot, &hba->outstanding_tasks);
+	__set_bit(task_tag, &hba->outstanding_tasks);
 
 	/* Make sure descriptors are ready before ringing the task doorbell */
 	wmb();
 
-	ufshcd_writel(hba, 1 << free_slot, REG_UTP_TASK_REQ_DOOR_BELL);
+	ufshcd_writel(hba, 1 << task_tag, REG_UTP_TASK_REQ_DOOR_BELL);
 	/* Make sure that doorbell is committed immediately */
 	wmb();
 
@@ -6497,24 +6494,24 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
 		ufshcd_add_tm_upiu_trace(hba, task_tag, UFS_TM_ERR);
 		dev_err(hba->dev, "%s: task management cmd 0x%.2x timed-out\n",
 				__func__, tm_function);
-		if (ufshcd_clear_tm_cmd(hba, free_slot))
-			dev_WARN(hba->dev, "%s: unable clear tm cmd (slot %d) after timeout\n",
-					__func__, free_slot);
+		if (ufshcd_clear_tm_cmd(hba, task_tag))
+			dev_WARN(hba->dev, "%s: unable to clear tm cmd (slot %d) after timeout\n",
+					__func__, task_tag);
 		err = -ETIMEDOUT;
 	} else {
 		err = 0;
-		memcpy(treq, hba->utmrdl_base_addr + free_slot, sizeof(*treq));
+		memcpy(treq, hba->utmrdl_base_addr + task_tag, sizeof(*treq));
 
 		ufshcd_add_tm_upiu_trace(hba, task_tag, UFS_TM_COMP);
 	}
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
-	__clear_bit(free_slot, &hba->outstanding_tasks);
+	__clear_bit(task_tag, &hba->outstanding_tasks);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 
+	ufshcd_release(hba);
 	blk_put_request(req);
 
-	ufshcd_release(hba);
 	return err;
 }
 
-- 
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