megaraid_sas: Do not allow PCI access during OCR

This patch will do synhronization between OCR function and AEN function
using "reset_mutex" lock.  reset_mutex will be acquired only in the
first half of the AEN function which issues a DCMD. Second half of the
function which calls SCSI API (scsi_add_device/scsi_remove_device)
should be out of reset_mutex to avoid deadlock between scsi_eh thread
and driver.

During chip reset (inside OCR function), there should not be any PCI
access and AEN function (which is called in delayed context) may be
firing DCMDs (doing PCI writes) when chip reset is happening in parallel
which will cause FW fault. This patch will solve the problem by making
AEN thread and OCR thread mutually exclusive.
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/megaraid/megaraid_sas.h

@@ -1083,6 +1083,8 @@ struct megasas_ctrl_info {
 
 #define VD_EXT_DEBUG 0
 
+#define SCAN_PD_CHANNEL	0x1
+#define SCAN_VD_CHANNEL	0x2
 
 enum MR_SCSI_CMD_TYPE {
 	READ_WRITE_LDIO = 0,

drivers/scsi/megaraid/megaraid_sas_base.c

@@ -5476,7 +5476,6 @@ static int megasas_probe_one(struct pci_dev *pdev,
 	spin_lock_init(&instance->hba_lock);
 	spin_lock_init(&instance->completion_lock);
 
-	mutex_init(&instance->aen_mutex);
 	mutex_init(&instance->reset_mutex);
 
 	/*
@@ -6442,10 +6441,10 @@ static int megasas_mgmt_ioctl_aen(struct file *file, unsigned long arg)
 	}
 	spin_unlock_irqrestore(&instance->hba_lock, flags);
 
-	mutex_lock(&instance->aen_mutex);
+	mutex_lock(&instance->reset_mutex);
 	error = megasas_register_aen(instance, aen.seq_num,
 				     aen.class_locale_word);
-	mutex_unlock(&instance->aen_mutex);
+	mutex_unlock(&instance->reset_mutex);
 	return error;
 }
 
@@ -6647,6 +6646,7 @@ megasas_aen_polling(struct work_struct *work)
 	int     i, j, doscan = 0;
 	u32 seq_num, wait_time = MEGASAS_RESET_WAIT_TIME;
 	int error;
+	u8  dcmd_ret = 0;
 
 	if (!instance) {
 		printk(KERN_ERR "invalid instance!\n");
@@ -6659,16 +6659,7 @@ megasas_aen_polling(struct work_struct *work)
 		wait_time = MEGASAS_ROUTINE_WAIT_TIME_VF;
 
 	/* Don't run the event workqueue thread if OCR is running */
-	for (i = 0; i < wait_time; i++) {
-		if (instance->adprecovery == MEGASAS_HBA_OPERATIONAL)
-			break;
-		if (!(i % MEGASAS_RESET_NOTICE_INTERVAL)) {
-			dev_notice(&instance->pdev->dev, "%s waiting for "
-			       "controller reset to finish for scsi%d\n",
-			       __func__, instance->host->host_no);
-		}
-		msleep(1000);
-	}
+	mutex_lock(&instance->reset_mutex);
 
 	instance->ev = NULL;
 	host = instance->host;
@@ -6676,212 +6667,127 @@ megasas_aen_polling(struct work_struct *work)
 		megasas_decode_evt(instance);
 
 		switch (le32_to_cpu(instance->evt_detail->code)) {
-		case MR_EVT_PD_INSERTED:
-			if (megasas_get_pd_list(instance) == 0) {
-			for (i = 0; i < MEGASAS_MAX_PD_CHANNELS; i++) {
-				for (j = 0;
-				j < MEGASAS_MAX_DEV_PER_CHANNEL;
-				j++) {
-
-				pd_index =
-				(i * MEGASAS_MAX_DEV_PER_CHANNEL) + j;
-
-				sdev1 = scsi_device_lookup(host, i, j, 0);
-
-				if (instance->pd_list[pd_index].driveState
-						== MR_PD_STATE_SYSTEM) {
-					if (!sdev1)
-						scsi_add_device(host, i, j, 0);
-
-					if (sdev1)
-						scsi_device_put(sdev1);
-					}
-				}
-			}
-			}
-			doscan = 0;
-			break;
 
+		case MR_EVT_PD_INSERTED:
 		case MR_EVT_PD_REMOVED:
-			if (megasas_get_pd_list(instance) == 0) {
-			for (i = 0; i < MEGASAS_MAX_PD_CHANNELS; i++) {
-				for (j = 0;
-				j < MEGASAS_MAX_DEV_PER_CHANNEL;
-				j++) {
-
-				pd_index =
-				(i * MEGASAS_MAX_DEV_PER_CHANNEL) + j;
-
-				sdev1 = scsi_device_lookup(host, i, j, 0);
-
-				if (instance->pd_list[pd_index].driveState
-					== MR_PD_STATE_SYSTEM) {
-					if (sdev1)
-						scsi_device_put(sdev1);
-				} else {
-					if (sdev1) {
-						scsi_remove_device(sdev1);
-						scsi_device_put(sdev1);
-					}
-				}
-				}
-			}
-			}
-			doscan = 0;
+			dcmd_ret = megasas_get_pd_list(instance);
+			if (dcmd_ret == 0)
+				doscan = SCAN_PD_CHANNEL;
 			break;
 
 		case MR_EVT_LD_OFFLINE:
 		case MR_EVT_CFG_CLEARED:
 		case MR_EVT_LD_DELETED:
-			if (!instance->requestorId ||
-			    megasas_get_ld_vf_affiliation(instance, 0)) {
-				if (megasas_ld_list_query(instance,
-							  MR_LD_QUERY_TYPE_EXPOSED_TO_HOST))
-					megasas_get_ld_list(instance);
-				for (i = 0; i < MEGASAS_MAX_LD_CHANNELS; i++) {
-					for (j = 0;
-					     j < MEGASAS_MAX_DEV_PER_CHANNEL;
-					     j++) {
-
-						ld_index =
-							(i * MEGASAS_MAX_DEV_PER_CHANNEL) + j;
-
-						sdev1 = scsi_device_lookup(host, MEGASAS_MAX_PD_CHANNELS + i, j, 0);
-
-						if (instance->ld_ids[ld_index]
-						    != 0xff) {
-							if (sdev1)
-								scsi_device_put(sdev1);
-						} else {
-							if (sdev1) {
-								scsi_remove_device(sdev1);
-								scsi_device_put(sdev1);
-							}
-						}
-					}
-				}
-				doscan = 0;
-			}
-			break;
 		case MR_EVT_LD_CREATED:
 			if (!instance->requestorId ||
-			    megasas_get_ld_vf_affiliation(instance, 0)) {
-				if (megasas_ld_list_query(instance,
-							  MR_LD_QUERY_TYPE_EXPOSED_TO_HOST))
-					megasas_get_ld_list(instance);
-				for (i = 0; i < MEGASAS_MAX_LD_CHANNELS; i++) {
-					for (j = 0;
-					     j < MEGASAS_MAX_DEV_PER_CHANNEL;
-					     j++) {
-						ld_index =
-							(i * MEGASAS_MAX_DEV_PER_CHANNEL) + j;
-
-						sdev1 = scsi_device_lookup(host, MEGASAS_MAX_PD_CHANNELS + i, j, 0);
-
-						if (instance->ld_ids[ld_index]
-						    != 0xff) {
-							if (!sdev1)
-								scsi_add_device(host, MEGASAS_MAX_PD_CHANNELS + i, j, 0);
-						}
-						if (sdev1)
-							scsi_device_put(sdev1);
-					}
-				}
-				doscan = 0;
-			}
+				(instance->requestorId && megasas_get_ld_vf_affiliation(instance, 0)))
+				dcmd_ret = megasas_ld_list_query(instance, MR_LD_QUERY_TYPE_EXPOSED_TO_HOST);
+
+			if (dcmd_ret == 0)
+				doscan = SCAN_VD_CHANNEL;
+
 			break;
+
 		case MR_EVT_CTRL_HOST_BUS_SCAN_REQUESTED:
 		case MR_EVT_FOREIGN_CFG_IMPORTED:
 		case MR_EVT_LD_STATE_CHANGE:
-			doscan = 1;
+			dcmd_ret = megasas_get_pd_list(instance);
+
+			if (dcmd_ret != 0)
+				break;
+
+			if (!instance->requestorId ||
+				(instance->requestorId && megasas_get_ld_vf_affiliation(instance, 0)))
+				dcmd_ret = megasas_ld_list_query(instance, MR_LD_QUERY_TYPE_EXPOSED_TO_HOST);
+
+			if (dcmd_ret != 0)
+				break;
+
+			doscan = SCAN_VD_CHANNEL | SCAN_PD_CHANNEL;
+			dev_info(&instance->pdev->dev, "scanning for scsi%d...\n",
+				instance->host->host_no);
 			break;
+
 		case MR_EVT_CTRL_PROP_CHANGED:
-			megasas_get_ctrl_info(instance);
-			break;
+				dcmd_ret = megasas_get_ctrl_info(instance);
+				break;
 		default:
 			doscan = 0;
 			break;
 		}
 	} else {
 		dev_err(&instance->pdev->dev, "invalid evt_detail!\n");
+		mutex_unlock(&instance->reset_mutex);
 		kfree(ev);
 		return;
 	}
 
-	if (doscan) {
-		dev_info(&instance->pdev->dev, "scanning for scsi%d...\n",
-		       instance->host->host_no);
-		if (megasas_get_pd_list(instance) == 0) {
-			for (i = 0; i < MEGASAS_MAX_PD_CHANNELS; i++) {
-				for (j = 0; j < MEGASAS_MAX_DEV_PER_CHANNEL; j++) {
-					pd_index = i*MEGASAS_MAX_DEV_PER_CHANNEL + j;
-					sdev1 = scsi_device_lookup(host, i, j, 0);
-					if (instance->pd_list[pd_index].driveState ==
-					    MR_PD_STATE_SYSTEM) {
-						if (!sdev1) {
-							scsi_add_device(host, i, j, 0);
-						}
-						if (sdev1)
-							scsi_device_put(sdev1);
-					} else {
-						if (sdev1) {
-							scsi_remove_device(sdev1);
-							scsi_device_put(sdev1);
-						}
+	mutex_unlock(&instance->reset_mutex);
+
+	if (doscan & SCAN_PD_CHANNEL) {
+		for (i = 0; i < MEGASAS_MAX_PD_CHANNELS; i++) {
+			for (j = 0; j < MEGASAS_MAX_DEV_PER_CHANNEL; j++) {
+				pd_index = i*MEGASAS_MAX_DEV_PER_CHANNEL + j;
+				sdev1 = scsi_device_lookup(host, i, j, 0);
+				if (instance->pd_list[pd_index].driveState ==
+							MR_PD_STATE_SYSTEM) {
+					if (!sdev1)
+						scsi_add_device(host, i, j, 0);
+					else
+						scsi_device_put(sdev1);
+				} else {
+					if (sdev1) {
+						scsi_remove_device(sdev1);
+						scsi_device_put(sdev1);
 					}
 				}
 			}
 		}
+	}
 
-		if (!instance->requestorId ||
-		    megasas_get_ld_vf_affiliation(instance, 0)) {
-			if (megasas_ld_list_query(instance,
-						  MR_LD_QUERY_TYPE_EXPOSED_TO_HOST))
-				megasas_get_ld_list(instance);
-			for (i = 0; i < MEGASAS_MAX_LD_CHANNELS; i++) {
-				for (j = 0; j < MEGASAS_MAX_DEV_PER_CHANNEL;
-				     j++) {
-					ld_index =
-						(i * MEGASAS_MAX_DEV_PER_CHANNEL) + j;
-
-					sdev1 = scsi_device_lookup(host,
-								   MEGASAS_MAX_PD_CHANNELS + i, j, 0);
-					if (instance->ld_ids[ld_index]
-					    != 0xff) {
-						if (!sdev1)
-							scsi_add_device(host, MEGASAS_MAX_PD_CHANNELS + i, j, 0);
-						else
-							scsi_device_put(sdev1);
-					} else {
-						if (sdev1) {
-							scsi_remove_device(sdev1);
-							scsi_device_put(sdev1);
-						}
+	if (doscan & SCAN_VD_CHANNEL) {
+		for (i = 0; i < MEGASAS_MAX_LD_CHANNELS; i++) {
+			for (j = 0; j < MEGASAS_MAX_DEV_PER_CHANNEL; j++) {
+				ld_index = (i * MEGASAS_MAX_DEV_PER_CHANNEL) + j;
+				sdev1 = scsi_device_lookup(host, MEGASAS_MAX_PD_CHANNELS + i, j, 0);
+				if (instance->ld_ids[ld_index] != 0xff) {
+					if (!sdev1)
+						scsi_add_device(host, MEGASAS_MAX_PD_CHANNELS + i, j, 0);
+					else
+						scsi_device_put(sdev1);
+				} else {
+					if (sdev1) {
+						scsi_remove_device(sdev1);
+						scsi_device_put(sdev1);
 					}
 				}
 			}
 		}
 	}
 
-	if (instance->aen_cmd != NULL) {
-		kfree(ev);
-		return ;
-	}
-
-	seq_num = le32_to_cpu(instance->evt_detail->seq_num) + 1;
+	if (dcmd_ret == 0)
+		seq_num = le32_to_cpu(instance->evt_detail->seq_num) + 1;
+	else
+		seq_num = instance->last_seq_num;
 
 	/* Register AEN with FW for latest sequence number plus 1 */
 	class_locale.members.reserved = 0;
 	class_locale.members.locale = MR_EVT_LOCALE_ALL;
 	class_locale.members.class = MR_EVT_CLASS_DEBUG;
-	mutex_lock(&instance->aen_mutex);
+
+	if (instance->aen_cmd != NULL) {
+		kfree(ev);
+		return;
+	}
+
+	mutex_lock(&instance->reset_mutex);
 	error = megasas_register_aen(instance, seq_num,
 					class_locale.word);
-	mutex_unlock(&instance->aen_mutex);
-
 	if (error)
-		dev_err(&instance->pdev->dev, "register aen failed error %x\n", error);
+		dev_err(&instance->pdev->dev,
+			"register aen failed error %x\n", error);
 
+	mutex_unlock(&instance->reset_mutex);
 	kfree(ev);
 }