Make multiple passes over RLC to get all data

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c

@@ -822,10 +822,15 @@ void nr_schedule_ue_spec(module_id_t module_id,
                                           NULL); // contention res id
       buf += written;
       int size = TBS - written;
-
-      DevAssert(size > 3);
+      DevAssert(size >= 0);
 
       /* next, get RLC data */
+
+      const int lcid = DL_SCH_LCID_DTCH;
+      int dlsch_total_bytes = 0;
+      if (sched_ctrl->num_total_bytes > 0) {
+        tbs_size_t len = 0;
+        while (size > 3) {
           // we do not know how much data we will get from RLC, i.e., whether it
           // will be longer than 256B or not. Therefore, reserve space for long header, then
           // fetch data, then fill real length
@@ -833,13 +838,10 @@ void nr_schedule_ue_spec(module_id_t module_id,
           buf += 3;
           size -= 3;
 
-      const int lcid = DL_SCH_LCID_DTCH;
-      int dlsch_total_bytes = 0;
-      if (sched_ctrl->num_total_bytes > 0) {
-        /* this is the data from the RLC we would like to request (e.g., only
-         * some bytes for first LC and some more from a second one */
+          /* limit requested number of bytes to what preprocessor specified, or
+           * such that TBS is full */
           const rlc_buffer_occupancy_t ndata = min(sched_ctrl->rlc_status[lcid].bytes_in_buffer, size);
-        const tbs_size_t len = mac_rlc_data_req(module_id,
+          len = mac_rlc_data_req(module_id,
                                  rnti,
                                  module_id,
                                  frame,
@@ -860,6 +862,8 @@ void nr_schedule_ue_spec(module_id_t module_id,
                 lcid,
                 ndata,
                 size);
+          if (len == 0)
+            break;
 
           header->R = 0;
           header->F = 1;
@@ -870,7 +874,19 @@ void nr_schedule_ue_spec(module_id_t module_id,
           buf += len;
           dlsch_total_bytes += len;
         }
+        if (len == 0) {
+          /* RLC did not have data anymore, mark buffer as unused */
+          buf -= 3;
+          size += 3;
+        }
+      }
       else if (get_softmodem_params()->phy_test || get_softmodem_params()->do_ra) {
+        /* we will need the large header, phy-test typically allocates all
+         * resources and fills to the last byte below */
+        NR_MAC_SUBHEADER_LONG *header = (NR_MAC_SUBHEADER_LONG *) buf;
+        buf += 3;
+        size -= 3;
+        DevAssert(size > 0);
         LOG_D(MAC, "Configuring DL_TX in %d.%d: TBS %d with %d B of random data\n", frame, slot, TBS, size);
         // fill dlsch_buffer with random data
         for (int i = 0; i < size; i++)