Be conservative with the array_of_indices

We were assuming that the array_of_indices has the same size as the
number of requests (incount), instead of the numberr of actually
active requests. While the patch is trivial, the question of the
size of the array_of_indices should be clarified in the MPI Forum.

cherry-picked from: a5fbfa4 (PR #4897 )

Signed-off-by: George Bosilca <[email protected]>

Author: bosilca

ompi/request/req_wait.c

@@ -3,7 +3,7 @@
  * Copyright (c) 2004-2010 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2016 The University of Tennessee and The University
+ * Copyright (c) 2004-2018 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2008 High Performance Computing Center Stuttgart,
@@ -378,13 +378,13 @@ int ompi_request_default_wait_some(size_t count,
                                    int * indices,
                                    ompi_status_public_t * statuses)
 {
-    size_t num_requests_null_inactive=0, num_requests_done=0;
+    size_t num_requests_null_inactive, num_requests_done, num_active_reqs;
     int rc = MPI_SUCCESS;
     ompi_request_t **rptr = NULL;
     ompi_request_t *request = NULL;
     ompi_wait_sync_t sync;
     size_t sync_sets = 0, sync_unsets = 0;
-    
+
     if (OPAL_UNLIKELY(0 == count)) {
         *outcount = MPI_UNDEFINED;
         return OMPI_SUCCESS;
@@ -397,6 +397,7 @@ int ompi_request_default_wait_some(size_t count,
     rptr = requests;
     num_requests_null_inactive = 0;
     num_requests_done = 0;
+    num_active_reqs = 0;
     for (size_t i = 0; i < count; i++, rptr++) {
         request = *rptr;
         /*
@@ -407,14 +408,14 @@ int ompi_request_default_wait_some(size_t count,
             num_requests_null_inactive++;
             continue;
         }
-        indices[i] = OPAL_ATOMIC_CMPSET_PTR(&request->req_complete, REQUEST_PENDING, &sync);
-        if( !indices[i] ) {
+        indices[num_active_reqs] = OPAL_ATOMIC_CMPSET_PTR(&request->req_complete, REQUEST_PENDING, &sync);
+        if( !indices[num_active_reqs] ) {
             /* If the request is completed go ahead and mark it as such */
             assert( REQUEST_COMPLETE(request) );
             num_requests_done++;
         }
+        num_active_reqs++;
     }
-    sync_sets = count - num_requests_null_inactive - num_requests_done;
 
     if(num_requests_null_inactive == count) {
         *outcount = MPI_UNDEFINED;
@@ -423,6 +424,7 @@ int ompi_request_default_wait_some(size_t count,
         return rc;
     }
 
+    sync_sets = num_active_reqs - num_requests_done;
     if( 0 == num_requests_done ) {
         /* One completed request is enough to satisfy the some condition */
         SYNC_WAIT(&sync);
@@ -433,6 +435,7 @@ int ompi_request_default_wait_some(size_t count,
 
     rptr = requests;
     num_requests_done = 0;
+    num_active_reqs = 0;
     for (size_t i = 0; i < count; i++, rptr++) {
         request = *rptr;
 
@@ -452,13 +455,14 @@ int ompi_request_default_wait_some(size_t count,
          * either slowly (in case of partial completion)
          * OR in parallel with `i` (in case of full set completion)  
          */
-        if( !indices[i] ){
+        if( !indices[num_active_reqs] ) {
             indices[num_requests_done++] = i;
         } else if( !OPAL_ATOMIC_CMPSET_PTR(&request->req_complete, &sync, REQUEST_PENDING) ) {
             indices[num_requests_done++] = i;
         }
+        num_active_reqs++;
     }
-    sync_unsets = count - num_requests_null_inactive - num_requests_done;
+    sync_unsets = num_active_reqs - num_requests_done;
 
     if( sync_sets == sync_unsets ){
         /* nobody knows about us,