Support reconfiguration of number of HARQ processes

In F1, the time until the serving cell config comes from CU can be
longer than when we want to schedule a particular UE. Then, if we don't
configure the default number of HARQ processes, we can have a segfault.

In this commit, we initially configure 8 HARQ processes. When we get the
right number from RRC, we reconfigure.

openair2/LAYER2/NR_MAC_gNB/config.c

@@ -628,16 +628,10 @@ int rrc_mac_config_req_gNB(module_id_t Mod_idP,
       const NR_ServingCellConfig_t *servingCellConfig = CellGroup ? CellGroup->spCellConfig->spCellConfigDedicated : NULL;
       NR_UE_sched_ctrl_t *sched_ctrl = &UE_info->UE_sched_ctrl[UE_id];
       const NR_PDSCH_ServingCellConfig_t *pdsch = servingCellConfig ? servingCellConfig->pdsch_ServingCellConfig->choice.setup : NULL;
-      if (sched_ctrl->available_dl_harq.len == 0) {
+      if (get_softmodem_params()->sa) {
         // add all available DL HARQ processes for this UE in SA
         create_dl_harq_list(sched_ctrl, pdsch);
       }
-      else {
-        const int nrofHARQ = pdsch && pdsch->nrofHARQ_ProcessesForPDSCH ?
-                             get_nrofHARQ_ProcessesForPDSCH(*pdsch->nrofHARQ_ProcessesForPDSCH) : 8;
-        AssertFatal(sched_ctrl->available_dl_harq.len==nrofHARQ,
-                    "Reconfiguration of available harq processes not yet supported\n");
-      }
       // update coreset/searchspace
       void *bwpd = NULL;
       NR_BWP_t *genericParameters = NULL;

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c

@@ -1942,14 +1942,46 @@ void dump_nr_list(NR_list_t *listP)
 void create_nr_list(NR_list_t *list, int len)
 {
   list->head = -1;
-  list->next = calloc(len, sizeof(*list->next));
-  AssertFatal(list, "cannot calloc() memory for NR_list_t->next\n");
+  list->next = malloc(len * sizeof(*list->next));
+  LOG_W(NR_MAC, "NR list->next %p\n", list->next);
+  AssertFatal(list->next, "cannot calloc() memory for NR_list_t->next\n");
   for (int i = 0; i < len; ++i)
     list->next[i] = -1;
   list->tail = -1;
   list->len = len;
 }
 
+/*
+ * Resize an NR_list
+ */
+void resize_nr_list(NR_list_t *list, int new_len)
+{
+  if (new_len == list->len)
+    return;
+  if (new_len > list->len) {
+    /* list->head remains */
+    const int old_len = list->len;
+    int* n = realloc(list->next, new_len * sizeof(*list->next));
+    AssertFatal(n, "cannot realloc() memory for NR_list_t->next\n");
+    list->next = n;
+    for (int i = old_len; i < new_len; ++i)
+      list->next[i] = -1;
+    /* list->tail remains */
+    list->len = new_len;
+  } else { /* new_len < len */
+    AssertFatal(list->head < new_len, "shortened list head out of index %d (new len %d)\n", list->head, new_len);
+    AssertFatal(list->tail < new_len, "shortened list tail out of index %d (new len %d)\n", list->head, new_len);
+    for (int i = 0; i < list->len; ++i)
+      AssertFatal(list->next[i] < new_len, "shortened list entry out of index %d (new len %d)\n", list->next[i], new_len);
+    /* list->head remains */
+    int *n = realloc(list->next, new_len * sizeof(*list->next));
+    AssertFatal(n, "cannot realloc() memory for NR_list_t->next\n");
+    list->next = n;
+    /* list->tail remains */
+    list->len = new_len;
+  }
+}
+
 /*
  * Destroy an NR_list
  */
@@ -2205,10 +2237,8 @@ int add_new_nr_ue(module_id_t mod_idP, rnti_t rntiP, NR_CellGroupConfig_t *CellG
 				       "no pdsch-ServingCellConfig found for UE %d\n",
 				       UE_id);
     const NR_PDSCH_ServingCellConfig_t *pdsch = servingCellConfig ? servingCellConfig->pdsch_ServingCellConfig->choice.setup : NULL;
-    // add DL HARQ processes for this UE only in NSA
-    // (SA still doesn't have information on nrofHARQ_ProcessesForPDSCH at this stage)
-    if (!get_softmodem_params()->sa)
-      create_dl_harq_list(sched_ctrl,pdsch);
+    // pdsch == NULL in SA -> will create default (8) number of HARQ processes
+    create_dl_harq_list(sched_ctrl, pdsch);
     // add all available UL HARQ processes for this UE
     // nb of ul harq processes not configurable
     create_nr_list(&sched_ctrl->available_ul_harq, 16);
@@ -2236,11 +2266,23 @@ void create_dl_harq_list(NR_UE_sched_ctrl_t *sched_ctrl,
   const int nrofHARQ = pdsch && pdsch->nrofHARQ_ProcessesForPDSCH ?
                        get_nrofHARQ_ProcessesForPDSCH(*pdsch->nrofHARQ_ProcessesForPDSCH) : 8;
   // add all available DL HARQ processes for this UE
+  AssertFatal(sched_ctrl->available_dl_harq.len == sched_ctrl->feedback_dl_harq.len
+              && sched_ctrl->available_dl_harq.len == sched_ctrl->retrans_dl_harq.len,
+              "HARQ lists have different lengths (%d/%d/%d)\n",
+              sched_ctrl->available_dl_harq.len,
+              sched_ctrl->feedback_dl_harq.len,
+              sched_ctrl->retrans_dl_harq.len);
+  if (sched_ctrl->available_dl_harq.len == 0) {
     create_nr_list(&sched_ctrl->available_dl_harq, nrofHARQ);
     for (int harq = 0; harq < nrofHARQ; harq++)
       add_tail_nr_list(&sched_ctrl->available_dl_harq, harq);
     create_nr_list(&sched_ctrl->feedback_dl_harq, nrofHARQ);
     create_nr_list(&sched_ctrl->retrans_dl_harq, nrofHARQ);
+  } else {
+    resize_nr_list(&sched_ctrl->available_dl_harq, nrofHARQ);
+    resize_nr_list(&sched_ctrl->feedback_dl_harq, nrofHARQ);
+    resize_nr_list(&sched_ctrl->retrans_dl_harq, nrofHARQ);
+  }
 }
 
 /* hack data to remove UE in the phy */

openair2/LAYER2/NR_MAC_gNB/mac_proto.h

@@ -351,6 +351,7 @@ int NRRIV2PRBOFFSET(int locationAndBandwidth,int N_RB);
 /* Functions to manage an NR_list_t */
 void dump_nr_list(NR_list_t *listP);
 void create_nr_list(NR_list_t *listP, int len);
+void resize_nr_list(NR_list_t *list, int new_len);
 void destroy_nr_list(NR_list_t *list);
 void add_nr_list(NR_list_t *listP, int id);
 void remove_nr_list(NR_list_t *listP, int id);