FlexRAN: lock sc_update with mutex

Prevent sc_update from being changed by an incoming slice reconfiguration
change while writing data to the scheduler

openair2/ENB_APP/CONTROL_MODULES/MAC/flexran_agent_mac.c

@@ -61,6 +61,8 @@ int perform_slice_config_update_count = 1;
 /* queue of incoming new UE<>slice association commands */
 Protocol__FlexUeConfig *ue_slice_assoc_update[NUM_MAX_UE];
 int n_ue_slice_assoc_updates = 0;
+/* mutex for sc_update: do not receive new config and write it at the same time */
+pthread_mutex_t sc_update_mtx = PTHREAD_MUTEX_INITIALIZER;
 
 
 int flexran_agent_mac_stats_reply(mid_t mod_id,
@@ -1446,10 +1448,13 @@ void flexran_agent_slice_update(mid_t mod_id)
   if (perform_slice_config_update_count <= 0) return;
   perform_slice_config_update_count--;
 
+  pthread_mutex_lock(&sc_update_mtx);
+
   if (!slice_config[mod_id]) {
     /* if the configuration does not exist for agent, create from eNB structure
      * and exit */
     flexran_create_config_structures(mod_id);
+    pthread_mutex_unlock(&sc_update_mtx);
     return;
   }
 
@@ -1479,6 +1484,7 @@ void flexran_agent_slice_update(mid_t mod_id)
       LOG_W(FLEXRAN_AGENT, "[%d] reverting to original number of %ld UL slices\n",
             mod_id, sc_update[mod_id]->n_ul);
     }
+    pthread_mutex_unlock(&sc_update_mtx);
     return;
   }
 
@@ -1514,6 +1520,7 @@ void flexran_agent_slice_update(mid_t mod_id)
   if (changes > 0)
     LOG_I(FLEXRAN_AGENT, "[%d] slice configuration: applied %d changes\n", mod_id, changes);
 
+  pthread_mutex_unlock(&sc_update_mtx);
 }
 
 Protocol__FlexSliceConfig *flexran_agent_get_slice_config(mid_t mod_id)

openair2/ENB_APP/CONTROL_MODULES/MAC/flexran_agent_mac_internal.c

@@ -38,6 +38,7 @@ extern Protocol__FlexSliceConfig *sc_update[NUM_MAX_ENB];
 extern int perform_slice_config_update_count;
 extern Protocol__FlexUeConfig *ue_slice_assoc_update[NUM_MAX_UE];
 extern int n_ue_slice_assoc_updates;
+extern pthread_mutex_t sc_update_mtx;
 
 Protocol__FlexranMessage * flexran_agent_generate_diff_mac_stats_report(Protocol__FlexranMessage *new_message,
 									Protocol__FlexranMessage *old_message) {
@@ -1228,6 +1229,9 @@ void prepare_update_slice_config(mid_t mod_id, Protocol__FlexSliceConfig *slice)
     LOG_E(FLEXRAN_AGENT, "Can not update slice policy (no existing slice profile)\n");
     return;
   }
+
+  pthread_mutex_lock(&sc_update_mtx);
+
   if (slice->n_dl == 0)
     LOG_I(FLEXRAN_AGENT, "[%d] no DL slice configuration in flex_slice_config message\n", mod_id);
   for (int i = 0; i < slice->n_dl; i++)
@@ -1238,6 +1242,8 @@ void prepare_update_slice_config(mid_t mod_id, Protocol__FlexSliceConfig *slice)
   for (int i = 0; i < slice->n_ul; i++)
     prepare_update_slice_config_ul(mod_id, slice->ul[i]);
 
+  pthread_mutex_unlock(&sc_update_mtx);
+
   /* perform the slice configuration reads a couple of times. If there are
    * inconsistencies (i.e. the MAC refuses a configuration), we will have a
    * couple of warnings because the current configuration and the one in
@@ -1395,7 +1401,6 @@ int apply_ue_slice_assoc_update(mid_t mod_id)
 {
   int i;
   int changes = 0;
-  /* TODO should lock structure */
   for (i = 0; i < n_ue_slice_assoc_updates; i++) {
     int ue_id = find_UE_id(mod_id, ue_slice_assoc_update[i]->rnti);
     if (ue_slice_assoc_update[i]->has_dl_slice_id) {