osc/rdma: Simplify query logic

With the change to load all btls in the alternate case and the
removal of the logic to change priority based on alternate or
accelerated btls, there's no point in running the full btl
query in osc_rdma_component_query().  Instead, just verify
that there is some number of BTLs available, which is the
extent of testing in the alternate case.

Signed-off-by: Brian Barrett <[email protected]>

Author: bwbarrett

ompi/mca/osc/rdma/osc_rdma_component.c

@@ -387,15 +387,14 @@ static int ompi_osc_rdma_component_query (struct ompi_win_t *win, void **base, s
     }
 #endif /* OPAL_CUDA_SUPPORT */
 
-    if (OMPI_SUCCESS == ompi_osc_rdma_query_accelerated_btls (comm, NULL)) {
-        return mca_osc_rdma_component.priority;
-    }
-
-    if (OMPI_SUCCESS == ompi_osc_rdma_query_alternate_btls (comm, NULL)) {
-        return mca_osc_rdma_component.priority;
+    /* verify if we have any btls available.  Since we do not verify
+     * connectivity across all btls in the alternate case, this is as
+     * good a test as we are going to have for success. */
+    if (opal_list_is_empty(&mca_btl_base_modules_initialized)) {
+        return -1;
     }
 
-    return -1;
+    return OMPI_SUCCESS;;
 }
 
 static int ompi_osc_rdma_initialize_region (ompi_osc_rdma_module_t *module, void **base, size_t size) {
@@ -914,13 +913,7 @@ static int ompi_osc_rdma_query_alternate_btls (ompi_communicator_t *comm, ompi_o
     mca_btl_base_selected_module_t *item;
     int ret;
 
-    /* shortcut the trivial query case */
-    if (NULL == module) {
-        if (opal_list_is_empty(&mca_btl_base_modules_initialized)) {
-            return OMPI_ERR_UNREACH;
-        }
-        return OMPI_SUCCESS;
-    }
+    assert(NULL != module);
 
     module->btls_in_use = 0;
 
@@ -988,9 +981,6 @@ static bool ompi_osc_rdma_check_accelerated_btl(struct mca_btl_base_module_t *bt
  * Testing (1) is expensive, so as an optimization, the
  * ompi_osc_rdma_full_connectivity_btls list contains the list of BTL
  * components we know can achieve (1) in almost all usage scenarios.
- *
- * If module is NULL, the code acts as a query mechanism to find any
- * potential BTLs, and is used to implement osc_rdma_query().
  */
 static int ompi_osc_rdma_query_accelerated_btls (ompi_communicator_t *comm, ompi_osc_rdma_module_t *module)
 {
@@ -999,11 +989,11 @@ static int ompi_osc_rdma_query_accelerated_btls (ompi_communicator_t *comm, ompi
     mca_bml_base_endpoint_t *base_endpoint;
     char **btls_to_use;
 
-    if (module) {
-        ompi_osc_rdma_selected_btl_insert(module, NULL, 0);
-        module->btls_in_use = 0;
-        module->use_memory_registration = false;
-    }
+    assert(NULL != module);
+
+    ompi_osc_rdma_selected_btl_insert(module, NULL, 0);
+    module->btls_in_use = 0;
+    module->use_memory_registration = false;
 
     /* Check for BTLs in the list of BTLs we know can reach all peers
        in general usage. */
@@ -1116,11 +1106,9 @@ static int ompi_osc_rdma_query_accelerated_btls (ompi_communicator_t *comm, ompi
     }
 
 btl_selection_complete:
-    if (module) {
-        ompi_osc_rdma_selected_btl_insert(module, selected_btl, 0);
-        module->btls_in_use = 1;
-        module->use_memory_registration = selected_btl->btl_register_mem != NULL;
-    }
+    ompi_osc_rdma_selected_btl_insert(module, selected_btl, 0);
+    module->btls_in_use = 1;
+    module->use_memory_registration = selected_btl->btl_register_mem != NULL;
 
     opal_output_verbose(MCA_BASE_VERBOSE_INFO, ompi_osc_base_framework.framework_output,
                         "accelerated_query: selected btl: %s",