ofi/common: fix code that broke sessions

With sessions initialization model (section 11.3 of MPI 4 standard)
MPI may be initialized and finalized any number of times.

This patch refactors code that was assuming a one shot init/finalize
sequence for initializing Open MPI and its MCA param space

The underlying problem with the replaced code was that an app call MPI_Session_finalize
and if there are no more instances active, the MCA param space is
destroyed.  So if one does not build Open MPI to use dynamically load frameworks,
and are using static variables in a way that assumes the MCA param
space is always preserved if a static variable is set to some value,
then things break if a subsequent MPI_Session_init is invoked.

Related to open-mpi#12869

Signed-off-by: Howard Pritchard <[email protected]>

Author: hppritcha

opal/mca/common/ofi/common_ofi.c

@@ -324,10 +324,11 @@ int opal_common_ofi_providers_subset_of_list(struct fi_info *provider_list, char
 
 int opal_common_ofi_mca_register(const mca_base_component_t *component)
 {
-    static int include_index = -1;
-    static int exclude_index = -1;
-    static int verbose_index = -1;
-    static int accelerator_rank_index = -1;
+    static int include_index;
+    static int exclude_index;
+    static int verbose_index;
+    static int accelerator_rank_index;
+    int param;
     int ret;
 
     if (fi_version() < FI_VERSION(1, 0)) {
@@ -336,7 +337,8 @@ int opal_common_ofi_mca_register(const mca_base_component_t *component)
 
     OPAL_THREAD_LOCK(&opal_common_ofi_mutex);
 
-    if (0 > include_index) {
+    param = mca_base_var_find("opal", "opal_common", "ofi", "provider_include");
+    if (0 > param) {
         /*
          * this monkey business is needed because of the way the MCA VARs stuff tries to handle
          * pointers to strings when when destructing the MCA var database.  If you don't do
@@ -359,9 +361,12 @@ int opal_common_ofi_mca_register(const mca_base_component_t *component)
             ret = include_index;
             goto err;
         }
+    } else {
+       include_index = param;
     }
 
-    if (0 > exclude_index) {
+    param = mca_base_var_find("opal", "opal_common", "ofi", "provider_exclude");
+    if (0 > param) {
         if (NULL == opal_common_ofi.prov_exclude) {
             opal_common_ofi.prov_exclude = (char **) malloc(sizeof(char *));
             assert(NULL != opal_common_ofi.prov_exclude);
@@ -378,9 +383,12 @@ int opal_common_ofi_mca_register(const mca_base_component_t *component)
             ret = exclude_index;
             goto err;
         }
+    } else {
+        exclude_index = param;
     }
 
-    if (0 > verbose_index) {
+    param = mca_base_var_find("opal", "opal_common", "ofi", "verbose");
+    if (0 > param) {
         verbose_index = mca_base_var_register("opal", "opal_common", "ofi", "verbose",
                                               "Verbose level of the OFI components",
                                               MCA_BASE_VAR_TYPE_INT, NULL, 0,
@@ -391,9 +399,13 @@ int opal_common_ofi_mca_register(const mca_base_component_t *component)
             ret = verbose_index;
             goto err;
         }
+    } else {
+        verbose_index = param;
     }
 
-    if (0 > accelerator_rank_index) {
+
+    param = mca_base_var_find("opal", "opal_common", "ofi", "accelerator_rank");
+    if (0 > param) {
         accelerator_rank_index
             = mca_base_var_register("opal", "opal_common", "ofi", "accelerator_rank",
                                     "Process rank(non-negative) on the selected accelerator device",
@@ -404,6 +416,8 @@ int opal_common_ofi_mca_register(const mca_base_component_t *component)
             ret = accelerator_rank_index;
             goto err;
         }
+    } else {
+        accelerator_rank_index = param;
     }
 
     if (component) {