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Two fixes for task management request implementation

PATCH Applied Can Guo 3 participants 5 messages Apr 1, 2021 – Apr 2, 2021 SCSI

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Can Guo

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#0 lore raw

v5 cover Two fixes for task management request implementation

These fixes are based on Jaegeuk's change - https://git.kernel.org/mkp/scsi/c/eeb1b55b6e25

Change since v4:
- Incorporated Daejun's comments

Change since v3:
- Deleted the 2nd change
- Incorporated Bart's comments

Change since v2:
- Split one change into 3 changes

Change since v1:
- Typo fixed

Can Guo (2):
scsi: ufs: Fix task management request completion timeout
scsi: ufs: Fix wrong Task Tag used in task management request UPIUs

 drivers/scsi/ufs/ufshcd.c | 31 ++++++++++++++-----------------
 1 file changed, 14 insertions(+), 17 deletions(-)
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Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
author
#1 lore raw

PATCH v5 1/2 scsi: ufs: Fix task management request completion timeout

ufshcd_tmc_handler() calls blk_mq_tagset_busy_iter(fn = ufshcd_compl_tm()), but since blk_mq_tagset_busy_iter() only iterates over all reserved tags and requests which are not in IDLE state, ufshcd_compl_tm() never gets a chance to run. Thus, TMR always ends up with completion timeout. Fix it by calling blk_mq_start_request() in __ufshcd_issue_tm_cmd().

Fixes 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to allocate and free TMFs")
Signed-off-by Can Guo <[email protected]>
---
 drivers/scsi/ufs/ufshcd.c | 1 +
 1 file changed, 1 insertion(+)
drivers/scsi/ufs/ufshcd.c +1 -0
index b49555fa..d4f8cb2 100644
@@ -6464,6 +6464,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
 
 	spin_lock_irqsave(host->host_lock, flags);
 	task_tag = hba->nutrs + free_slot;
+	blk_mq_start_request(req);
 
 	treq->req_header.dword_0 |= cpu_to_be32(task_tag);
Signature · 1 line
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
Reviewed-by on v5 1/2
#2 lore raw

Re: [PATCH v5 1/2] scsi: ufs: Fix task management request completion timeout

Quoted 5 lines · Can Guo

ufshcd_tmc_handler() calls blk_mq_tagset_busy_iter(fn = ufshcd_compl_tm()), but since blk_mq_tagset_busy_iter() only iterates over all reserved tags and requests which are not in IDLE state, ufshcd_compl_tm() never gets a chance to run. Thus, TMR always ends up with completion timeout. Fix it by calling blk_mq_start_request() in __ufshcd_issue_tm_cmd().

Reviewed-by Bart Van Assche <[email protected]>
author
#3 lore raw

PATCH v5 2/2 scsi: ufs: Fix wrong Task Tag used in task management request UPIUs

In reply to 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 <[email protected]>
Signed-off-by Can Guo <[email protected]>
---
 drivers/scsi/ufs/ufshcd.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)
drivers/scsi/ufs/ufshcd.c +13 -17
index d4f8cb2..ce5f3fea 100644
@@ -6446,38 +6446,34 @@ 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 +6493,24 @@ 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;
 }
Signature · 1 line
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
Applied
#4 lore raw
In reply to Can Guo
Quoted 10 lines · Can Guo

These fixes are based on Jaegeuk's change - https://git.kernel.org/mkp/scsi/c/eeb1b55b6e25

Change since v4:
- Incorporated Daejun's comments

Change since v3:
- Deleted the 2nd change
- Incorporated Bart's comments

[...]

Applied to 5.12/scsi-fixes, thanks!

[1/2] scsi: ufs: Fix task management request completion timeout

      https://git.kernel.org/mkp/scsi/c/1235fc569e0b
[2/2] scsi: ufs: Fix wrong Task Tag used in task management request UPIUs
      https://git.kernel.org/mkp/scsi/c/4b42d557a8ad
Signature · 1 line
Martin K. Petersen	Oracle Linux Engineering