scsi: pm8001: Fix tag values handling

The function pm8001_tag_alloc() determines free tags using the function
find_first_zero_bit() which can return 0 when the first bit of the bitmap
being inspected is 0. As such, tag 0 is a valid tag value that should not
be dismissed as invalid. Fix the functions pm8001_work_fn(),
mpi_sata_completion(), pm8001_mpi_task_abort_resp() and
pm8001_open_reject_retry() to not dismiss 0 tags as invalid.

The value 0xffffffff is used for invalid tags for unused ccb information
structures. Add the macro definition PM8001_INVALID_TAG to define this
value.

Link: https://lore.kernel.org/r/20220220031810.738362-20-damien.lemoal@opensource.wdc.comReviewed-by: NJack Wang <jinpu.wang@ionos.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/pm8001/pm8001_hwi.c

@@ -1522,7 +1522,6 @@ void pm8001_work_fn(struct work_struct *work)
 	case IO_XFER_ERROR_BREAK:
 	{	/* This one stashes the sas_task instead */
 		struct sas_task *t = (struct sas_task *)pm8001_dev;
-		u32 tag;
 		struct pm8001_ccb_info *ccb;
 		struct pm8001_hba_info *pm8001_ha = pw->pm8001_ha;
 		unsigned long flags, flags1;
@@ -1544,8 +1543,8 @@ void pm8001_work_fn(struct work_struct *work)
 		/* Search for a possible ccb that matches the task */
 		for (i = 0; ccb = NULL, i < PM8001_MAX_CCB; i++) {
 			ccb = &pm8001_ha->ccb_info[i];
-			tag = ccb->ccb_tag;
-			if ((tag != 0xFFFFFFFF) && (ccb->task == t))
+			if ((ccb->ccb_tag != PM8001_INVALID_TAG) &&
+			    (ccb->task == t))
 				break;
 		}
 		if (!ccb) {
@@ -1566,11 +1565,11 @@ void pm8001_work_fn(struct work_struct *work)
 			spin_unlock_irqrestore(&t->task_state_lock, flags1);
 			pm8001_dbg(pm8001_ha, FAIL, "task 0x%p done with event 0x%x resp 0x%x stat 0x%x but aborted by upper layer!\n",
 				   t, pw->handler, ts->resp, ts->stat);
-			pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
+			pm8001_ccb_task_free(pm8001_ha, t, ccb, ccb->ccb_tag);
 			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
 		} else {
 			spin_unlock_irqrestore(&t->task_state_lock, flags1);
-			pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
+			pm8001_ccb_task_free(pm8001_ha, t, ccb, ccb->ccb_tag);
 			mb();/* in order to force CPU ordering */
 			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
 			t->task_done(t);
@@ -1579,7 +1578,6 @@ void pm8001_work_fn(struct work_struct *work)
 	case IO_XFER_OPEN_RETRY_TIMEOUT:
 	{	/* This one stashes the sas_task instead */
 		struct sas_task *t = (struct sas_task *)pm8001_dev;
-		u32 tag;
 		struct pm8001_ccb_info *ccb;
 		struct pm8001_hba_info *pm8001_ha = pw->pm8001_ha;
 		unsigned long flags, flags1;
@@ -1613,8 +1611,8 @@ void pm8001_work_fn(struct work_struct *work)
 		/* Search for a possible ccb that matches the task */
 		for (i = 0; ccb = NULL, i < PM8001_MAX_CCB; i++) {
 			ccb = &pm8001_ha->ccb_info[i];
-			tag = ccb->ccb_tag;
-			if ((tag != 0xFFFFFFFF) && (ccb->task == t))
+			if ((ccb->ccb_tag != PM8001_INVALID_TAG) &&
+			    (ccb->task == t))
 				break;
 		}
 		if (!ccb) {
@@ -1685,19 +1683,13 @@ void pm8001_work_fn(struct work_struct *work)
 		struct task_status_struct *ts;
 		struct sas_task *task;
 		int i;
-		u32 tag, device_id;
+		u32 device_id;
 
 		for (i = 0; ccb = NULL, i < PM8001_MAX_CCB; i++) {
 			ccb = &pm8001_ha->ccb_info[i];
 			task = ccb->task;
 			ts = &task->task_status;
-			tag = ccb->ccb_tag;
-			/* check if tag is NULL */
-			if (!tag) {
-				pm8001_dbg(pm8001_ha, FAIL,
-					"tag Null\n");
-				continue;
-			}
+
 			if (task != NULL) {
 				dev = task->dev;
 				if (!dev) {
@@ -1706,10 +1698,11 @@ void pm8001_work_fn(struct work_struct *work)
 					continue;
 				}
 				/*complete sas task and update to top layer */
-				pm8001_ccb_task_free(pm8001_ha, task, ccb, tag);
+				pm8001_ccb_task_free(pm8001_ha, task, ccb,
+						     ccb->ccb_tag);
 				ts->resp = SAS_TASK_COMPLETE;
 				task->task_done(task);
-			} else if (tag != 0xFFFFFFFF) {
+			} else if (ccb->ccb_tag != PM8001_INVALID_TAG) {
 				/* complete the internal commands/non-sas task */
 				pm8001_dev = ccb->device;
 				if (pm8001_dev->dcompletion) {
@@ -1717,7 +1710,7 @@ void pm8001_work_fn(struct work_struct *work)
 					pm8001_dev->dcompletion = NULL;
 				}
 				complete(pm8001_ha->nvmd_completion);
-				pm8001_tag_free(pm8001_ha, tag);
+				pm8001_tag_free(pm8001_ha, ccb->ccb_tag);
 			}
 		}
 		/* Deregister all the device ids  */
@@ -2313,11 +2306,6 @@ mpi_sata_completion(struct pm8001_hba_info *pm8001_ha, void *piomb)
 	param = le32_to_cpu(psataPayload->param);
 	tag = le32_to_cpu(psataPayload->tag);
 
-	if (!tag) {
-		pm8001_dbg(pm8001_ha, FAIL, "tag null\n");
-		return;
-	}
-
 	ccb = &pm8001_ha->ccb_info[tag];
 	t = ccb->task;
 	pm8001_dev = ccb->device;
@@ -3051,7 +3039,7 @@ void pm8001_mpi_set_dev_state_resp(struct pm8001_hba_info *pm8001_ha,
 		   device_id, pds, nds, status);
 	complete(pm8001_dev->setds_completion);
 	ccb->task = NULL;
-	ccb->ccb_tag = 0xFFFFFFFF;
+	ccb->ccb_tag = PM8001_INVALID_TAG;
 	pm8001_tag_free(pm8001_ha, tag);
 }
 
@@ -3069,7 +3057,7 @@ void pm8001_mpi_set_nvmd_resp(struct pm8001_hba_info *pm8001_ha, void *piomb)
 				dlen_status);
 	}
 	ccb->task = NULL;
-	ccb->ccb_tag = 0xFFFFFFFF;
+	ccb->ccb_tag = PM8001_INVALID_TAG;
 	pm8001_tag_free(pm8001_ha, tag);
 }
 
@@ -3096,7 +3084,7 @@ pm8001_mpi_get_nvmd_resp(struct pm8001_hba_info *pm8001_ha, void *piomb)
 		 * freed by requesting path anywhere.
 		 */
 		ccb->task = NULL;
-		ccb->ccb_tag = 0xFFFFFFFF;
+		ccb->ccb_tag = PM8001_INVALID_TAG;
 		pm8001_tag_free(pm8001_ha, tag);
 		return;
 	}
@@ -3142,7 +3130,7 @@ pm8001_mpi_get_nvmd_resp(struct pm8001_hba_info *pm8001_ha, void *piomb)
 	complete(pm8001_ha->nvmd_completion);
 	pm8001_dbg(pm8001_ha, MSG, "Get nvmd data complete!\n");
 	ccb->task = NULL;
-	ccb->ccb_tag = 0xFFFFFFFF;
+	ccb->ccb_tag = PM8001_INVALID_TAG;
 	pm8001_tag_free(pm8001_ha, tag);
 }
 
@@ -3555,7 +3543,7 @@ int pm8001_mpi_reg_resp(struct pm8001_hba_info *pm8001_ha, void *piomb)
 	}
 	complete(pm8001_dev->dcompletion);
 	ccb->task = NULL;
-	ccb->ccb_tag = 0xFFFFFFFF;
+	ccb->ccb_tag = PM8001_INVALID_TAG;
 	pm8001_tag_free(pm8001_ha, htag);
 	return 0;
 }
@@ -3627,7 +3615,7 @@ int pm8001_mpi_fw_flash_update_resp(struct pm8001_hba_info *pm8001_ha,
 	}
 	kfree(ccb->fw_control_context);
 	ccb->task = NULL;
-	ccb->ccb_tag = 0xFFFFFFFF;
+	ccb->ccb_tag = PM8001_INVALID_TAG;
 	pm8001_tag_free(pm8001_ha, tag);
 	complete(pm8001_ha->nvmd_completion);
 	return 0;
@@ -3663,10 +3651,6 @@ int pm8001_mpi_task_abort_resp(struct pm8001_hba_info *pm8001_ha, void *piomb)
 
 	status = le32_to_cpu(pPayload->status);
 	tag = le32_to_cpu(pPayload->tag);
-	if (!tag) {
-		pm8001_dbg(pm8001_ha, FAIL, " TAG NULL. RETURNING !!!\n");
-		return -1;
-	}
 
 	scp = le32_to_cpu(pPayload->scp);
 	ccb = &pm8001_ha->ccb_info[tag];

drivers/scsi/pm8001/pm8001_init.c

@@ -1217,10 +1217,11 @@ pm8001_init_ccb_tag(struct pm8001_hba_info *pm8001_ha, struct Scsi_Host *shost,
 			goto err_out;
 		}
 		pm8001_ha->ccb_info[i].task = NULL;
-		pm8001_ha->ccb_info[i].ccb_tag = 0xffffffff;
+		pm8001_ha->ccb_info[i].ccb_tag = PM8001_INVALID_TAG;
 		pm8001_ha->ccb_info[i].device = NULL;
 		++pm8001_ha->tags_num;
 	}
+
 	return 0;
 
 err_out_noccb:

drivers/scsi/pm8001/pm8001_sas.c

@@ -553,7 +553,7 @@ void pm8001_ccb_task_free(struct pm8001_hba_info *pm8001_ha,
 
 	task->lldd_task = NULL;
 	ccb->task = NULL;
-	ccb->ccb_tag = 0xFFFFFFFF;
+	ccb->ccb_tag = PM8001_INVALID_TAG;
 	ccb->open_retry = 0;
 	pm8001_tag_free(pm8001_ha, ccb_idx);
 }
@@ -831,9 +831,11 @@ void pm8001_open_reject_retry(
 		struct task_status_struct *ts;
 		struct pm8001_device *pm8001_dev;
 		unsigned long flags1;
-		u32 tag;
 		struct pm8001_ccb_info *ccb = &pm8001_ha->ccb_info[i];
 
+		if (ccb->ccb_tag == PM8001_INVALID_TAG)
+			continue;
+
 		pm8001_dev = ccb->device;
 		if (!pm8001_dev || (pm8001_dev->dev_type == SAS_PHY_UNUSED))
 			continue;
@@ -845,9 +847,6 @@ void pm8001_open_reject_retry(
 				continue;
 		} else if (pm8001_dev != device_to_close)
 			continue;
-		tag = ccb->ccb_tag;
-		if (!tag || (tag == 0xFFFFFFFF))
-			continue;
 		task = ccb->task;
 		if (!task || !task->task_done)
 			continue;
@@ -867,11 +866,11 @@ void pm8001_open_reject_retry(
 				& SAS_TASK_STATE_ABORTED))) {
 			spin_unlock_irqrestore(&task->task_state_lock,
 				flags1);
-			pm8001_ccb_task_free(pm8001_ha, task, ccb, tag);
+			pm8001_ccb_task_free(pm8001_ha, task, ccb, ccb->ccb_tag);
 		} else {
 			spin_unlock_irqrestore(&task->task_state_lock,
 				flags1);
-			pm8001_ccb_task_free(pm8001_ha, task, ccb, tag);
+			pm8001_ccb_task_free(pm8001_ha, task, ccb, ccb->ccb_tag);
 			mb();/* in order to force CPU ordering */
 			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
 			task->task_done(task);

drivers/scsi/pm8001/pm8001_sas.h

@@ -732,6 +732,8 @@ void pm8001_free_dev(struct pm8001_device *pm8001_dev);
 /* ctl shared API */
 extern const struct attribute_group *pm8001_host_groups[];
 
+#define PM8001_INVALID_TAG	((u32)-1)
+
 static inline void
 pm8001_ccb_task_free_done(struct pm8001_hba_info *pm8001_ha,
 			struct sas_task *task, struct pm8001_ccb_info *ccb,

drivers/scsi/pm8001/pm80xx_hwi.c

@@ -2402,11 +2402,6 @@ mpi_sata_completion(struct pm8001_hba_info *pm8001_ha,
 	param = le32_to_cpu(psataPayload->param);
 	tag = le32_to_cpu(psataPayload->tag);
 
-	if (!tag) {
-		pm8001_dbg(pm8001_ha, FAIL, "tag null\n");
-		return;
-	}
-
 	ccb = &pm8001_ha->ccb_info[tag];
 	t = ccb->task;
 	pm8001_dev = ccb->device;