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scsi: ufs: read door bell register after clearing interrupt aggregation

PATCH In review Dolev Raviv 3 participants 4 messages Aug 25, 2013 – Aug 30, 2013

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Dolev Raviv

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#0 lore raw

PATCH 1/1 scsi: ufs: read door bell register after clearing interrupt aggregation

In interrupt context, after reading and comparing the UTRLDBR to hba->outstanding_request and before resetting the interrupt aggregation, there might be completion of another transfer request (TR). Such TRs might get stuck, pending, until the next interrupt is generated.

The fix reads the UTRLDBR after resetting the interrupt aggregation and handles completed TRs.

Signed-off-by Dolev Raviv <[email protected]>
drivers/scsi/ufs/ufshcd.c +35 -33
index 4dca9b4..30c84d8 100644
@@ -1915,6 +1915,13 @@ static void ufshcd_uic_cmd_compl(struct ufs_hba *hba)
 /**
  * ufshcd_transfer_req_compl - handle SCSI and query command completion
  * @hba: per adapter instance
+ *
+ * Resetting interrupt aggregation counters first and reading the DOOR_BELL
+ * afterward , allows us to handle all the completed requests.
+ * In order to prevent other interrupts starvation the DB is read once
+ * after reset. The down side of this solution is the possibility of false
+ * interrupt if device completes another request after resetting aggregation
+ * and before reading the DB.
  */
 static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
 {

@@ -1924,47 +1931,36 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
 	u32 tr_doorbell;
 	int result;
 	int index;
-	bool int_aggr_reset = false;
+
+	/* Reset interrupt aggregation counters */
+	ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
 
 	tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
 	completed_reqs = tr_doorbell ^ hba->outstanding_reqs;
 
-	for (index = 0; index < hba->nutrs; index++) {
-		if (test_bit(index, &completed_reqs)) {
-			lrbp = &hba->lrb[index];
-			cmd = lrbp->cmd;
-			/*
-			 * Don't skip resetting interrupt aggregation counters
-			 * if a regular command is present.
-			 */
-			int_aggr_reset |= !lrbp->intr_cmd;
-
-			if (cmd) {
-				result = ufshcd_transfer_rsp_status(hba, lrbp);
-				scsi_dma_unmap(cmd);
-				cmd->result = result;
-				/* Mark completed command as NULL in LRB */
-				lrbp->cmd = NULL;
-				clear_bit_unlock(index, &hba->lrb_in_use);
-				/* Do not touch lrbp after scsi done */
-				cmd->scsi_done(cmd);
-			} else if (lrbp->command_type ==
-					UTP_CMD_TYPE_DEV_MANAGE) {
-				if (hba->dev_cmd.complete)
-					complete(hba->dev_cmd.complete);
-			}
-		} /* end of if */
-	} /* end of for */
+	for_each_set_bit(index, &completed_reqs, hba->nutrs) {
+		lrbp = &hba->lrb[index];
+		cmd = lrbp->cmd;
+		if (cmd) {
+			result = ufshcd_transfer_rsp_status(hba, lrbp);
+			scsi_dma_unmap(cmd);
+			cmd->result = result;
+			/* Mark completed command as NULL in LRB */
+			lrbp->cmd = NULL;
+			clear_bit_unlock(index, &hba->lrb_in_use);
+			/* Do not touch lrbp after scsi done */
+			cmd->scsi_done(cmd);
+		} else if (lrbp->command_type == UTP_CMD_TYPE_DEV_MANAGE) {
+			if (hba->dev_cmd.complete)
+				complete(hba->dev_cmd.complete);
+		}
+	} /* end of for_each_set_bit */
 
 	/* clear corresponding bits of completed commands */
 	hba->outstanding_reqs ^= completed_reqs;
 
 	/* we might have free'd some tags above */
 	wake_up(&hba->dev_cmd.tag_wq);
-
-	/* Reset interrupt aggregation counters */
-	if (int_aggr_reset)
-		ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
 }
 
 /**

@@ -2569,6 +2565,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	int poll_cnt;
 	u8 resp = 0xF;
 	struct ufshcd_lrb *lrbp;
+	u32 reg;
 
 	host = cmd->device->host;
 	hba = shost_priv(host);

@@ -2578,6 +2575,13 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	if (!(test_bit(tag, &hba->outstanding_reqs)))
 		goto out;
 
+	reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+	if (!(reg & (1 << tag))) {
+		dev_err(hba->dev,
+		"%s: cmd was completed, but without a notifying intr, tag = %d",
+		__func__, tag);
+	}
+
 	lrbp = &hba->lrb[tag];
 	for (poll_cnt = 100; poll_cnt; poll_cnt--) {
 		err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,

@@ -2586,8 +2590,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 			/* cmd pending in the device */
 			break;
 		} else if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
-			u32 reg;
-
 			/*
 			 * cmd not pending in the device, check if it is
 			 * in transition.
Signature · 4 lines
1.7.6
-- 
QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
Reviewed-by on v1 1/1
#1 lore raw

Looks good to me.

Reviewed-by Subhash Jadavani <[email protected]>
Quoted 127 lines · Dolev Raviv

In interrupt context, after reading and comparing the UTRLDBR to hba->outstanding_request and before resetting the interrupt aggregation, there might be completion of another transfer request (TR). Such TRs might get stuck, pending, until the next interrupt is generated.

The fix reads the UTRLDBR after resetting the interrupt aggregation and handles completed TRs.

Signed-off-by Dolev Raviv <[email protected]>
drivers/scsi/ufs/ufshcd.c +35 -33
index 4dca9b4..30c84d8 100644
@@ -1915,6 +1915,13 @@ static void ufshcd_uic_cmd_compl(struct ufs_hba *hba)
  /**
   * ufshcd_transfer_req_compl - handle SCSI and query command completion
   * @hba: per adapter instance
+ *
+ * Resetting interrupt aggregation counters first and reading the DOOR_BELL
+ * afterward , allows us to handle all the completed requests.
+ * In order to prevent other interrupts starvation the DB is read once
+ * after reset. The down side of this solution is the possibility of false
+ * interrupt if device completes another request after resetting aggregation
+ * and before reading the DB.
   */
  static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
  {

@@ -1924,47 +1931,36 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
  	u32 tr_doorbell;
  	int result;
  	int index;
-	bool int_aggr_reset = false;
+
+	/* Reset interrupt aggregation counters */
+	ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
 
  	tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
  	completed_reqs = tr_doorbell ^ hba->outstanding_reqs;
 
-	for (index = 0; index < hba->nutrs; index++) {
-		if (test_bit(index, &completed_reqs)) {
-			lrbp = &hba->lrb[index];
-			cmd = lrbp->cmd;
-			/*
-			 * Don't skip resetting interrupt aggregation counters
-			 * if a regular command is present.
-			 */
-			int_aggr_reset |= !lrbp->intr_cmd;
-
-			if (cmd) {
-				result = ufshcd_transfer_rsp_status(hba, lrbp);
-				scsi_dma_unmap(cmd);
-				cmd->result = result;
-				/* Mark completed command as NULL in LRB */
-				lrbp->cmd = NULL;
-				clear_bit_unlock(index, &hba->lrb_in_use);
-				/* Do not touch lrbp after scsi done */
-				cmd->scsi_done(cmd);
-			} else if (lrbp->command_type ==
-					UTP_CMD_TYPE_DEV_MANAGE) {
-				if (hba->dev_cmd.complete)
-					complete(hba->dev_cmd.complete);
-			}
-		} /* end of if */
-	} /* end of for */
+	for_each_set_bit(index, &completed_reqs, hba->nutrs) {
+		lrbp = &hba->lrb[index];
+		cmd = lrbp->cmd;
+		if (cmd) {
+			result = ufshcd_transfer_rsp_status(hba, lrbp);
+			scsi_dma_unmap(cmd);
+			cmd->result = result;
+			/* Mark completed command as NULL in LRB */
+			lrbp->cmd = NULL;
+			clear_bit_unlock(index, &hba->lrb_in_use);
+			/* Do not touch lrbp after scsi done */
+			cmd->scsi_done(cmd);
+		} else if (lrbp->command_type == UTP_CMD_TYPE_DEV_MANAGE) {
+			if (hba->dev_cmd.complete)
+				complete(hba->dev_cmd.complete);
+		}
+	} /* end of for_each_set_bit */
 
  	/* clear corresponding bits of completed commands */
  	hba->outstanding_reqs ^= completed_reqs;
 
  	/* we might have free'd some tags above */
  	wake_up(&hba->dev_cmd.tag_wq);
-
-	/* Reset interrupt aggregation counters */
-	if (int_aggr_reset)
-		ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
  }
 
  /**

@@ -2569,6 +2565,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
  	int poll_cnt;
  	u8 resp = 0xF;
  	struct ufshcd_lrb *lrbp;
+	u32 reg;
 
  	host = cmd->device->host;
  	hba = shost_priv(host);

@@ -2578,6 +2575,13 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
  	if (!(test_bit(tag, &hba->outstanding_reqs)))
  		goto out;
 
+	reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+	if (!(reg & (1 << tag))) {
+		dev_err(hba->dev,
+		"%s: cmd was completed, but without a notifying intr, tag = %d",
+		__func__, tag);
+	}
+
  	lrbp = &hba->lrb[tag];
  	for (poll_cnt = 100; poll_cnt; poll_cnt--) {
  		err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,

@@ -2586,8 +2590,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
  			/* cmd pending in the device */
  			break;
  		} else if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
-			u32 reg;
-
  			/*
  			 * cmd not pending in the device, check if it is
  			 * in transition.
#2 lore raw
Quoted 40 lines · Subhash Jadavani

Looks good to me.

Reviewed-by Subhash Jadavani <[email protected]>
Quoted 34 lines · Dolev Raviv

In interrupt context, after reading and comparing the UTRLDBR to hba->outstanding_request and before resetting the interrupt aggregation, there might be completion of another transfer request (TR). Such TRs might get stuck, pending, until the next interrupt is generated.

The fix reads the UTRLDBR after resetting the interrupt aggregation and handles completed TRs.

Signed-off-by Dolev Raviv <[email protected]>
drivers/scsi/ufs/ufshcd.c +0 -0
index 4dca9b4..30c84d8 100644
@@ -1915,6 +1915,13 @@ static void ufshcd_uic_cmd_compl(struct 
 ufs_hba *hba)
  /**
   * ufshcd_transfer_req_compl - handle SCSI and query command

completion
* @hba: per adapter instance
+ *
+ * Resetting interrupt aggregation counters first and reading the DOOR_BELL
+ * afterward , allows us to handle all the completed requests.
+ * In order to prevent other interrupts starvation the DB is read once
+ * after reset. The down side of this solution is the possibility of false
+ * interrupt if device completes another request after resetting aggregation
+ * and before reading the DB.
*/
static void ufshcd_transfer_req_compl(struct ufs_hba *hba) {

drivers/scsi/ufs/ufshcd.c +0 -0
@@ -1924,47 +1931,36 @@ static void ufshcd_transfer_req_compl(struct
Quoted 8 lines

drivers/scsi/ufs/ufshcd.c static void ufshcd_transfer_req_compl(struct ufs_hba *hba) · line 1936

Quoted 8 lines
drivers/scsi/ufs/ufshcd.c +3 -1
 ufs_hba *hba)
      u32 tr_doorbell;
      int result;
      int index;
-    bool int_aggr_reset = false;
+
+    /* Reset interrupt aggregation counters */
+    ufshcd_config_int_aggr(hba, INT_AGGR_RESET);

You may have to rebase your change on top of "[PATCH v3 2/6] scsi: ufs: fix the setting interrupt aggregation counter" patch. Once you do that, you will be calling ufshcd_reset_intr_aggr() (instead of ufshscd_config_int_aggr()) to reset the interrupt aggregation counters.

Quoted 90 lines
Quoted 85 lines
drivers/scsi/ufs/ufshcd.c +24 -31
        tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
      completed_reqs = tr_doorbell ^ hba->outstanding_reqs;
  -    for (index = 0; index < hba->nutrs; index++) {
-        if (test_bit(index, &completed_reqs)) {
-            lrbp = &hba->lrb[index];
-            cmd = lrbp->cmd;
-            /*
-             * Don't skip resetting interrupt aggregation counters
-             * if a regular command is present.
-             */
-            int_aggr_reset |= !lrbp->intr_cmd;
-
-            if (cmd) {
-                result = ufshcd_transfer_rsp_status(hba, lrbp);
-                scsi_dma_unmap(cmd);
-                cmd->result = result;
-                /* Mark completed command as NULL in LRB */
-                lrbp->cmd = NULL;
-                clear_bit_unlock(index, &hba->lrb_in_use);
-                /* Do not touch lrbp after scsi done */
-                cmd->scsi_done(cmd);
-            } else if (lrbp->command_type ==
-                    UTP_CMD_TYPE_DEV_MANAGE) {
-                if (hba->dev_cmd.complete)
-                    complete(hba->dev_cmd.complete);
-            }
-        } /* end of if */
-    } /* end of for */
+    for_each_set_bit(index, &completed_reqs, hba->nutrs) {
+        lrbp = &hba->lrb[index];
+        cmd = lrbp->cmd;
+        if (cmd) {
+            result = ufshcd_transfer_rsp_status(hba, lrbp);
+            scsi_dma_unmap(cmd);
+            cmd->result = result;
+            /* Mark completed command as NULL in LRB */
+            lrbp->cmd = NULL;
+            clear_bit_unlock(index, &hba->lrb_in_use);
+            /* Do not touch lrbp after scsi done */
+            cmd->scsi_done(cmd);
+        } else if (lrbp->command_type == UTP_CMD_TYPE_DEV_MANAGE) {
+            if (hba->dev_cmd.complete)
+                complete(hba->dev_cmd.complete);
+        }
+    } /* end of for_each_set_bit */
        /* clear corresponding bits of completed commands */
      hba->outstanding_reqs ^= completed_reqs;
        /* we might have free'd some tags above */
      wake_up(&hba->dev_cmd.tag_wq);
-
-    /* Reset interrupt aggregation counters */
-    if (int_aggr_reset)
-        ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
  }
    /**

@@ -2569,6 +2565,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
      int poll_cnt;
      u8 resp = 0xF;
      struct ufshcd_lrb *lrbp;
+    u32 reg;
        host = cmd->device->host;
      hba = shost_priv(host);

@@ -2578,6 +2575,13 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
      if (!(test_bit(tag, &hba->outstanding_reqs)))
          goto out;
  +    reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+    if (!(reg & (1 << tag))) {
+        dev_err(hba->dev,
+        "%s: cmd was completed, but without a notifying intr, tag = 
 %d",
+        __func__, tag);
+    }
+
      lrbp = &hba->lrb[tag];
      for (poll_cnt = 100; poll_cnt; poll_cnt--) {
          err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,

@@ -2586,8 +2590,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
              /* cmd pending in the device */
              break;
          } else if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
-            u32 reg;
-
              /*
               * cmd not pending in the device, check if it is
               * in transition.
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Tested-by
#3 lore raw
Tested-by Yaniv Gardi <[email protected]>

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Subhash Jadavani
Sent: Tuesday, August 27, 2013 11:59 AM
To: Dolev Raviv
Cc: [email protected]; [email protected]; open list
Subject: Re: [PATCH] scsi: ufs: read door bell register after clearing interrupt aggregation

Quoted 42 lines · Subhash Jadavani

Looks good to me.

Reviewed-by Subhash Jadavani <[email protected]>
Quoted 36 lines · Dolev Raviv

In interrupt context, after reading and comparing the UTRLDBR to hba->outstanding_request and before resetting the interrupt hba->aggregation,
there might be completion of another transfer request (TR). Such TRs might get stuck, pending, until the next interrupt is generated.

The fix reads the UTRLDBR after resetting the interrupt aggregation and handles completed TRs.

Signed-off-by Dolev Raviv <[email protected]>
drivers/scsi/ufs/ufshcd.c +0 -0
index 4dca9b4..30c84d8 100644
@@ -1915,6 +1915,13 @@ static void ufshcd_uic_cmd_compl(struct 
 ufs_hba *hba)
  /**
   * ufshcd_transfer_req_compl - handle SCSI and query command

completion
* @hba: per adapter instance
+ *
+ * Resetting interrupt aggregation counters first and reading the DOOR_BELL
+ * afterward , allows us to handle all the completed requests.
+ * In order to prevent other interrupts starvation the DB is read
+ once
+ * after reset. The down side of this solution is the possibility of false
+ * interrupt if device completes another request after resetting aggregation
+ * and before reading the DB.
*/
static void ufshcd_transfer_req_compl(struct ufs_hba *hba) {

drivers/scsi/ufs/ufshcd.c +0 -0
@@ -1924,47 +1931,36 @@ static void ufshcd_transfer_req_compl(struct
Quoted 8 lines

drivers/scsi/ufs/ufshcd.c static void ufshcd_transfer_req_compl(struct ufs_hba *hba) · line 1936

Quoted 8 lines
drivers/scsi/ufs/ufshcd.c +3 -1
 ufs_hba *hba)
      u32 tr_doorbell;
      int result;
      int index;
-    bool int_aggr_reset = false;
+
+    /* Reset interrupt aggregation counters */
+    ufshcd_config_int_aggr(hba, INT_AGGR_RESET);

You may have to rebase your change on top of "[PATCH v3 2/6] scsi: ufs:
fix the setting interrupt aggregation counter" patch. Once you do that, you will be calling ufshcd_reset_intr_aggr() (instead of ufshscd_config_int_aggr()) to reset the interrupt aggregation counters.

Quoted 82 lines
Quoted 82 lines
drivers/scsi/ufs/ufshcd.c +24 -31
        tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
      completed_reqs = tr_doorbell ^ hba->outstanding_reqs;
  -    for (index = 0; index < hba->nutrs; index++) {
-        if (test_bit(index, &completed_reqs)) {
-            lrbp = &hba->lrb[index];
-            cmd = lrbp->cmd;
-            /*
-             * Don't skip resetting interrupt aggregation counters
-             * if a regular command is present.
-             */
-            int_aggr_reset |= !lrbp->intr_cmd;
-
-            if (cmd) {
-                result = ufshcd_transfer_rsp_status(hba, lrbp);
-                scsi_dma_unmap(cmd);
-                cmd->result = result;
-                /* Mark completed command as NULL in LRB */
-                lrbp->cmd = NULL;
-                clear_bit_unlock(index, &hba->lrb_in_use);
-                /* Do not touch lrbp after scsi done */
-                cmd->scsi_done(cmd);
-            } else if (lrbp->command_type ==
-                    UTP_CMD_TYPE_DEV_MANAGE) {
-                if (hba->dev_cmd.complete)
-                    complete(hba->dev_cmd.complete);
-            }
-        } /* end of if */
-    } /* end of for */
+    for_each_set_bit(index, &completed_reqs, hba->nutrs) {
+        lrbp = &hba->lrb[index];
+        cmd = lrbp->cmd;
+        if (cmd) {
+            result = ufshcd_transfer_rsp_status(hba, lrbp);
+            scsi_dma_unmap(cmd);
+            cmd->result = result;
+            /* Mark completed command as NULL in LRB */
+            lrbp->cmd = NULL;
+            clear_bit_unlock(index, &hba->lrb_in_use);
+            /* Do not touch lrbp after scsi done */
+            cmd->scsi_done(cmd);
+        } else if (lrbp->command_type == UTP_CMD_TYPE_DEV_MANAGE) {
+            if (hba->dev_cmd.complete)
+                complete(hba->dev_cmd.complete);
+        }
+    } /* end of for_each_set_bit */
        /* clear corresponding bits of completed commands */
      hba->outstanding_reqs ^= completed_reqs;
        /* we might have free'd some tags above */
      wake_up(&hba->dev_cmd.tag_wq);
-
-    /* Reset interrupt aggregation counters */
-    if (int_aggr_reset)
-        ufshcd_config_int_aggr(hba, INT_AGGR_RESET);
  }
    /**

@@ -2569,6 +2565,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
      int poll_cnt;
      u8 resp = 0xF;
      struct ufshcd_lrb *lrbp;
+    u32 reg;
        host = cmd->device->host;
      hba = shost_priv(host);

@@ -2578,6 +2575,13 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
      if (!(test_bit(tag, &hba->outstanding_reqs)))
          goto out;
  +    reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+    if (!(reg & (1 << tag))) {
+        dev_err(hba->dev,
+        "%s: cmd was completed, but without a notifying intr, tag =
 %d",
+        __func__, tag);
+    }
+
      lrbp = &hba->lrb[tag];
      for (poll_cnt = 100; poll_cnt; poll_cnt--) {
          err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag, 

@@ -2586,8 +2590,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
              /* cmd pending in the device */
              break;
          } else if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
-            u32 reg;
-
Quoted 8 lines

drivers/scsi/ufs/ufshcd.c static int ufshcd_abort(struct scsi_cmnd *cmd) · line 2595

Quoted 3 lines
drivers/scsi/ufs/ufshcd.c +0 -0
              /*
               * cmd not pending in the device, check if it is
               * in transition.

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