coll/libnbc: do not recursively call opal_progress()

instead of invoking ompi_request_test_all(), that will end up
calling opal_progress() recursively, manually check the status
of the requests.

the same method is used in ompi_comm_request_progress()

Refs open-mpi/ompi#3901

Signed-off-by: Gilles Gouaillardet <gilles@rist.or.jp>

ompi/mca/coll/libnbc/nbc.c

@@ -10,7 +10,7 @@
  *                         rights reserved.
  * Copyright (c) 2015      Los Alamos National Security, LLC.  All rights
  *                         reserved.
- * Copyright (c) 2015-2017 Research Organization for Information Science
+ * Copyright (c) 2015-2018 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  *
  * Author(s): Torsten Hoefler <htor@cs.indiana.edu>
@@ -315,7 +315,8 @@ static inline void NBC_Free (NBC_Handle* handle) {
  *
  * to be called *only* from the progress thread !!! */
 int NBC_Progress(NBC_Handle *handle) {
-  int flag, res, ret=NBC_CONTINUE;
+  int res, ret=NBC_CONTINUE;
+  bool flag;
   unsigned long size = 0;
   char *delim;
   int i;
@@ -325,43 +326,27 @@ int NBC_Progress(NBC_Handle *handle) {
     return NBC_OK;
   }
 
+  flag = true;
+
   if ((handle->req_count > 0) && (handle->req_array != NULL)) {
     NBC_DEBUG(50, "NBC_Progress: testing for %i requests\n", handle->req_count);
 #ifdef NBC_TIMING
     Test_time -= MPI_Wtime();
 #endif
-    res = ompi_request_test_all(handle->req_count, handle->req_array, &flag, MPI_STATUSES_IGNORE);
-    if(res != OMPI_SUCCESS) {
-      // Attempt to cancel outstanding requests
-      for(i = 0; i < handle->req_count; ++i ) {
-        // If the request is complete, then try to report the error code
-        if( handle->req_array[i]->req_complete ) {
-          if( OMPI_SUCCESS != handle->req_array[i]->req_status.MPI_ERROR ) {
-            NBC_Error ("MPI Error in MPI_Testall() (req %d = %d)", i, handle->req_array[i]->req_status.MPI_ERROR);
-          }
+    /* don't call ompi_request_test_all as it causes a recursive call into opal_progress */
+    while (handle->req_count) {
+        ompi_request_t *subreq = handle->req_array[handle->req_count - 1];
+        if (REQUEST_COMPLETE(subreq)) {
+            ompi_request_free(&subreq);
+            handle->req_count--;
+        } else {
+            flag = false;
+            break;
         }
-        else {
-          ompi_request_cancel(handle->req_array[i]);
-          // If the PML actually canceled the request, then wait on it
-          if( handle->req_array[i]->req_status._cancelled) {
-            ompi_request_wait(&handle->req_array[i], &status);
-          }
-          // Warn the user that we had to leave a PML message outstanding so
-          // bad things could happen if they continue using nonblocking collectives
-          else {
-            NBC_Error ("MPI Error: Not able to cancel the internal request %d. "
-                       "Be aware that continuing to use nonblocking collectives on this communicator may result in undefined behavior.", i);
-          }
-        }
-      }
-
-      return OMPI_ERROR;
     }
 #ifdef NBC_TIMING
     Test_time += MPI_Wtime();
 #endif
-  } else {
-    flag = 1; /* we had no open requests -> proceed to next round */
   }
 
   /* a round is finished */