Prevent failover to direct_modex if key isn't found unless direct_modex was enabled

Refs trac:4258

This commit was SVN r30865.

The following Trac tickets were found above:
  Ticket 4258 --> https://svn.open-mpi.org/trac/ompi/ticket/4258

ompi/mca/rte/orte/rte_orte_module.c

@@ -145,6 +145,8 @@ void ompi_rte_wait_for_debugger(void)
     }
 }    
 
+static bool direct_modex_enabled = false;
+
 int ompi_rte_modex(ompi_rte_collective_t *coll)
 {
     /* mark that this process reached modex */
@@ -173,6 +175,8 @@ int ompi_rte_modex(ompi_rte_collective_t *coll)
     OPAL_OUTPUT_VERBOSE((2, orte_grpcomm_base_framework.framework_output,
                          "%s using direct modex",
                          ORTE_NAME_PRINT(ORTE_PROC_MY_NAME)));
+    direct_modex_enabled = true;
+
     /* if direct modex was enabled, setup the receive for it */
     orte_rml.recv_buffer_nb(OMPI_NAME_WILDCARD,
                             ORTE_RML_TAG_DIRECT_MODEX_RESP,
@@ -270,6 +274,7 @@ int ompi_rte_db_fetch(const struct ompi_proc_t *proc,
                          ORTE_NAME_PRINT(&proc->proc_name), key));
 
     if (OPAL_SUCCESS != (rc = opal_db.fetch((opal_identifier_t*)(&proc->proc_name), key, data, type))) {
+        if (direct_modex_enabled) {
             OPAL_OUTPUT_VERBOSE((2, orte_grpcomm_base_framework.framework_output,
                                  "%s requesting direct modex from %s for %s",
                                  ORTE_NAME_PRINT(ORTE_PROC_MY_NAME),
@@ -286,6 +291,9 @@ int ompi_rte_db_fetch(const struct ompi_proc_t *proc,
                 ORTE_ERROR_LOG(rc);
                 return rc;
             }
+        } else {
+            return rc;
+        }
     }
     /* update the hostname upon first call to modex-recv for this proc */
     if (NULL == proc->proc_hostname) {
@@ -306,6 +314,7 @@ int ompi_rte_db_fetch_pointer(const struct ompi_proc_t *proc,
                          ORTE_NAME_PRINT(&proc->proc_name), key));
 
     if (OPAL_SUCCESS != (rc = opal_db.fetch_pointer((opal_identifier_t*)(&proc->proc_name), key, data, type))) {
+        if (direct_modex_enabled) {
             /* if we couldn't fetch the data via the db, then we will attempt
              * to retrieve it from the target proc
              */
@@ -322,6 +331,9 @@ int ompi_rte_db_fetch_pointer(const struct ompi_proc_t *proc,
                 ORTE_ERROR_LOG(rc);
                 return rc;
             }
+        } else {
+            return rc;
+        }
     }
     /* update the hostname upon first call to modex-recv for this proc */
     if (NULL == proc->proc_hostname) {
@@ -344,6 +356,7 @@ int ompi_rte_db_fetch_multiple(const struct ompi_proc_t *proc,
     /* MPI processes are only concerned with shared info */
     if (OPAL_SUCCESS != (rc = opal_db.fetch_multiple((opal_identifier_t*)(&proc->proc_name),
                                                      OPAL_SCOPE_GLOBAL, key, kvs))) {
+        if (direct_modex_enabled) {
             /* if we couldn't fetch the data via the db, then we will attempt
              * to retrieve it from the target proc
              */
@@ -361,6 +374,9 @@ int ompi_rte_db_fetch_multiple(const struct ompi_proc_t *proc,
                 ORTE_ERROR_LOG(rc);
                 return rc;
             }
+        } else {
+            return rc;
+        }
     }
     /* update the hostname upon first call to modex-recv for this proc */
     if (NULL == proc->proc_hostname) {