scsi: smartpqi: Correct device removal for multi-actuator devices

Correct device count for multi-actuator drives which can cause kernel
panics.
Reviewed-by: Scott Benesh <scott.benesh@microchip.com>
Reviewed-by: Scott Teel <scott.teel@microchip.com>
Reviewed-by: Mike Mcgowan <mike.mcgowan@microchip.com>
Reviewed-by: Kevin Barnett <kevin.barnett@microchip.com>
Signed-off-by: Kumar Meiyappan <Kumar.Meiyappan@microchip.com>
Signed-off-by: Don Brace <don.brace@microchip.com>
Link: https://lore.kernel.org/r/166793531872.322537.9003385780343419275.stgit@brunhildaSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/smartpqi/smartpqi.h

@@ -1130,7 +1130,7 @@ struct pqi_scsi_dev {
 	u8	phy_id;
 	u8	ncq_prio_enable;
 	u8	ncq_prio_support;
-	u8	multi_lun_device_lun_count;
+	u8	lun_count;
 	bool	raid_bypass_configured;	/* RAID bypass configured */
 	bool	raid_bypass_enabled;	/* RAID bypass enabled */
 	u32	next_bypass_group[RAID_MAP_MAX_DATA_DISKS_PER_ROW];

drivers/scsi/smartpqi/smartpqi_init.c

@@ -1623,9 +1623,7 @@ static int pqi_get_physical_device_info(struct pqi_ctrl_info *ctrl_info,
 		&id_phys->alternate_paths_phys_connector,
 		sizeof(device->phys_connector));
 	device->bay = id_phys->phys_bay_in_box;
-	device->multi_lun_device_lun_count = id_phys->multi_lun_device_lun_count;
-	if (!device->multi_lun_device_lun_count)
-		device->multi_lun_device_lun_count = 1;
+	device->lun_count = id_phys->multi_lun_device_lun_count;
 	if ((id_phys->even_more_flags & PQI_DEVICE_PHY_MAP_SUPPORTED) &&
 		id_phys->phy_count)
 		device->phy_id =
@@ -1759,7 +1757,7 @@ static bool pqi_keep_device_offline(struct pqi_ctrl_info *ctrl_info,
 	return offline;
 }
 
-static int pqi_get_device_info(struct pqi_ctrl_info *ctrl_info,
+static int pqi_get_device_info_phys_logical(struct pqi_ctrl_info *ctrl_info,
 	struct pqi_scsi_dev *device,
 	struct bmic_identify_physical_device *id_phys)
 {
@@ -1776,6 +1774,20 @@ static int pqi_get_device_info(struct pqi_ctrl_info *ctrl_info,
 	return rc;
 }
 
+static int pqi_get_device_info(struct pqi_ctrl_info *ctrl_info,
+	struct pqi_scsi_dev *device,
+	struct bmic_identify_physical_device *id_phys)
+{
+	int rc;
+
+	rc = pqi_get_device_info_phys_logical(ctrl_info, device, id_phys);
+
+	if (rc == 0 && device->lun_count == 0)
+		device->lun_count = 1;
+
+	return rc;
+}
+
 static void pqi_show_volume_status(struct pqi_ctrl_info *ctrl_info,
 	struct pqi_scsi_dev *device)
 {
@@ -1910,7 +1922,7 @@ static inline void pqi_remove_device(struct pqi_ctrl_info *ctrl_info, struct pqi
 	int rc;
 	int lun;
 
-	for (lun = 0; lun < device->multi_lun_device_lun_count; lun++) {
+	for (lun = 0; lun < device->lun_count; lun++) {
 		rc = pqi_device_wait_for_pending_io(ctrl_info, device, lun,
 			PQI_REMOVE_DEVICE_PENDING_IO_TIMEOUT_MSECS);
 		if (rc)
@@ -2089,6 +2101,7 @@ static void pqi_scsi_update_device(struct pqi_ctrl_info *ctrl_info,
 	existing_device->sas_address = new_device->sas_address;
 	existing_device->queue_depth = new_device->queue_depth;
 	existing_device->device_offline = false;
+	existing_device->lun_count = new_device->lun_count;
 
 	if (pqi_is_logical_device(existing_device)) {
 		existing_device->is_external_raid_device = new_device->is_external_raid_device;
@@ -2121,10 +2134,6 @@ static void pqi_scsi_update_device(struct pqi_ctrl_info *ctrl_info,
 		existing_device->phy_connected_dev_type = new_device->phy_connected_dev_type;
 		memcpy(existing_device->box, new_device->box, sizeof(existing_device->box));
 		memcpy(existing_device->phys_connector, new_device->phys_connector, sizeof(existing_device->phys_connector));
-
-		existing_device->multi_lun_device_lun_count = new_device->multi_lun_device_lun_count;
-		if (existing_device->multi_lun_device_lun_count == 0)
-			existing_device->multi_lun_device_lun_count = 1;
 	}
 }
 
@@ -6502,6 +6511,12 @@ static void pqi_slave_destroy(struct scsi_device *sdev)
 		return;
 	}
 
+	device->lun_count--;
+	if (device->lun_count > 0) {
+		mutex_unlock(&ctrl_info->scan_mutex);
+		return;
+	}
+
 	spin_lock_irqsave(&ctrl_info->scsi_device_list_lock, flags);
 	list_del(&device->scsi_device_list_entry);
 	spin_unlock_irqrestore(&ctrl_info->scsi_device_list_lock, flags);