[SCSI] qla4xxx: Fix multiple conn login event issue during session recovery.

During iscsid session recovery driver sends multiple ISCSI_CONN_STATE_LOGGED_IN
event from qla4xxx_conn_start() and qla4xxx_ddb_change(), which causes iscsid
to crash.

Signed-off-by: Manish Rangankar <manish.rangankar@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/qla4xxx/ql4_os.c

@@ -3168,6 +3168,7 @@ int qla4xxx_unblock_ddb(struct iscsi_cls_session *cls_session)
 	struct iscsi_session *sess;
 	struct ddb_entry *ddb_entry;
 	struct scsi_qla_host *ha;
+	int status = QLA_SUCCESS;
 
 	sess = cls_session->dd_data;
 	ddb_entry = sess->dd_data;
@@ -3175,11 +3176,20 @@ int qla4xxx_unblock_ddb(struct iscsi_cls_session *cls_session)
 	ql4_printk(KERN_INFO, ha, "scsi%ld: %s: ddb[%d]"
 		   " unblock user space session\n", ha->host_no, __func__,
 		   ddb_entry->fw_ddb_index);
-	iscsi_conn_start(ddb_entry->conn);
-	iscsi_conn_login_event(ddb_entry->conn,
-			       ISCSI_CONN_STATE_LOGGED_IN);
 
-	return QLA_SUCCESS;
+	if (!iscsi_is_session_online(cls_session)) {
+		iscsi_conn_start(ddb_entry->conn);
+		iscsi_conn_login_event(ddb_entry->conn,
+				       ISCSI_CONN_STATE_LOGGED_IN);
+	} else {
+		ql4_printk(KERN_INFO, ha,
+			   "scsi%ld: %s: ddb[%d] session [%d] already logged in\n",
+			   ha->host_no, __func__, ddb_entry->fw_ddb_index,
+			   cls_session->sid);
+		status = QLA_ERROR;
+	}
+
+	return status;
 }
 
 static void qla4xxx_relogin_all_devices(struct scsi_qla_host *ha)