refactor: do some internal refactor.

source/dnode/vnode/src/tq/tq.c

@@ -1415,7 +1415,10 @@ int32_t tqProcessSubmitReq(STQ* pTq, SPackedData submit) {
 
     tqDebug("data submit enqueue stream task:%d, ver: %" PRId64, pTask->taskId, submit.ver);
     if (succ) {
-      if (tAppendDataForStream(pTask, (SStreamQueueItem*)pSubmit) < 0) {
+      int32_t code = tAppendDataForStream(pTask, (SStreamQueueItem*)pSubmit);
+      if (code < 0) {
+        // let's handle the back pressure
+
         tqError("stream task:%d failed to put into queue for, too many", pTask->taskId);
         continue;
       }

source/libs/stream/src/stream.c

@@ -310,6 +310,7 @@ int32_t tAppendDataForStream(SStreamTask* pTask, SStreamQueueItem* pItem) {
   // TODO: back pressure
   atomic_store_8(&pTask->inputStatus, TASK_INPUT_STATUS__NORMAL);
 #endif
+
   return 0;
 }