diff -uNr '--exclude=*.o' openvswitch-2.10.1/ofproto/ofproto.c openvswitch-2.10.1_modified/ofproto/ofproto.c
--- openvswitch-2.10.1/ofproto/ofproto.c    2018-10-19 15:57:46.650077822 -0700
+++ openvswitch-2.10.1_modified/ofproto/ofproto.c        2019-03-05 00:16:27.436754000 -0800
@@ -5410,6 +5410,7 @@
                         const struct ofputil_flow_mod *fm)
     OVS_EXCLUDED(ofproto_mutex)
 {
+    enum ofperr error;
     rule_criteria_init(&ofm->criteria, fm->table_id, &fm->match, 0,
                        OVS_VERSION_MAX, fm->cookie, fm->cookie_mask, OFPP_ANY,
                        OFPG_ANY);
@@ -5417,9 +5418,9 @@
                              (fm->flags & OFPUTIL_FF_NO_READONLY) != 0);
     /* Must create a new flow in advance for the case that no matches are
      * found.  Also used for template for multiple modified flows. */
-    add_flow_init(ofproto, ofm, fm);
+    error = add_flow_init(ofproto, ofm, fm);

-    return 0;
+    return error;
 }

 /* Implements OFPFC_MODIFY.  Returns 0 on success or an OpenFlow error code on
@@ -5495,6 +5496,7 @@
                         const struct ofputil_flow_mod *fm)
     OVS_EXCLUDED(ofproto_mutex)
 {
+    enum ofperr error;
     rule_criteria_init(&ofm->criteria, fm->table_id, &fm->match, fm->priority,
                        OVS_VERSION_MAX, fm->cookie, fm->cookie_mask, OFPP_ANY,
                        OFPG_ANY);
@@ -5502,9 +5504,9 @@
                              (fm->flags & OFPUTIL_FF_NO_READONLY) != 0);
     /* Must create a new flow in advance for the case that no matches are
      * found.  Also used for template for multiple modified flows. */
-    add_flow_init(ofproto, ofm, fm);
+    error = add_flow_init(ofproto, ofm, fm);

-    return 0;
+    return error;
 }

 /* Implements OFPFC_MODIFY_STRICT.  Returns 0 on success or an OpenFlow error