scsi: hpsa: update queue depth for externals

Preserve external device queue depth during a scan operation.

Reviewed-by: Scott Benesh <scott.benesh@microsemi.com>
Reviewed-by: Scott Teel <scott.teel@microsemi.com>
Reviewed-by: Kevin Barnett <kevin.barnett@microsemi.com>
Signed-off-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 6a998b0..27a1aca 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -1765,8 +1765,12 @@ static void hpsa_figure_phys_disk_ptrs(struct ctlr_info *h,
 		 * way too high for partial stripe writes
 		 */
 		logical_drive->queue_depth = qdepth;
-	else
-		logical_drive->queue_depth = h->nr_cmds;
+	else {
+		if (logical_drive->external)
+			logical_drive->queue_depth = EXTERNAL_QD;
+		else
+			logical_drive->queue_depth = h->nr_cmds;
+	}
 }
 
 static void hpsa_update_log_drive_phys_drive_ptrs(struct ctlr_info *h,