npersocket should not be recomputed in odls_default_fork_local_procs: segfault might occur in some particular cases

diff -r ce3749a94a9e orte/mca/odls/base/odls_base_default_fns.c
--- a/orte/mca/odls/base/odls_base_default_fns.c	Fri Nov 04 13:31:18 2011 +0100
+++ b/orte/mca/odls/base/odls_base_default_fns.c	Fri Nov 04 13:55:00 2011 +0100
@@ -352,6 +352,12 @@ int orte_odls_base_default_get_add_procs
         return rc;
     }
     
+    /* pack the npersocket for this job */
+    if (ORTE_SUCCESS != (rc = opal_dss.pack(data, &map->npersocket, 1, OPAL_INT32))) {
+        ORTE_ERROR_LOG(rc);
+        return rc;
+    }
+
     /* pack the cpus_per_rank for this job */
     if (ORTE_SUCCESS != (rc = opal_dss.pack(data, &map->cpus_per_rank, 1, OPAL_INT16))) {
         ORTE_ERROR_LOG(rc);
@@ -809,6 +815,12 @@ int orte_odls_base_default_construct_chi
         ORTE_ERROR_LOG(rc);
         goto REPORT_ERROR;
     }
+    /* unpack the npersocket for the job */
+    cnt=1;
+    if (ORTE_SUCCESS != (rc = opal_dss.unpack(data, &jobdat->npersocket, &cnt, OPAL_INT32))) {
+        ORTE_ERROR_LOG(rc);
+        goto REPORT_ERROR;
+    }
     /* unpack the cpus/rank for the job */
     cnt=1;
     if (ORTE_SUCCESS != (rc = opal_dss.unpack(data, &jobdat->cpus_per_rank, &cnt, OPAL_INT16))) {
diff -r ce3749a94a9e orte/mca/odls/default/odls_default_module.c
--- a/orte/mca/odls/default/odls_default_module.c	Fri Nov 04 13:31:18 2011 +0100
+++ b/orte/mca/odls/default/odls_default_module.c	Fri Nov 04 13:55:00 2011 +0100
@@ -383,7 +383,7 @@ static int odls_default_fork_local_proc(
                 OPAL_PAFFINITY_CPU_ZERO(mask);
                 if (ORTE_MAPPING_NPERXXX & jobdat->policy) {
                     /* we need to balance the children from this job across the available sockets */
-                    npersocket = jobdat->num_local_procs / orte_odls_globals.num_sockets;
+                    npersocket = jobdat->npersocket;
                     /* determine the socket to use based on those available */
                     if (npersocket < 2) {
                         /* if we only have 1/sock, or we have less procs than sockets,
@@ -578,7 +578,7 @@ static int odls_default_fork_local_proc(
                 }
                 if (ORTE_MAPPING_NPERXXX & jobdat->policy) {
                     /* we need to balance the children from this job across the available sockets */
-                    npersocket = jobdat->num_local_procs / orte_odls_globals.num_sockets;
+                    npersocket = jobdat->npersocket;
                     /* determine the socket to use based on those available */
                     if (npersocket < 2) {
                         /* if we only have 1/sock, or we have less procs than sockets,
diff -r ce3749a94a9e orte/mca/odls/odls_types.h
--- a/orte/mca/odls/odls_types.h	Fri Nov 04 13:31:18 2011 +0100
+++ b/orte/mca/odls/odls_types.h	Fri Nov 04 13:55:00 2011 +0100
@@ -116,6 +116,7 @@ typedef struct orte_odls_job_t {
     orte_app_context_t      **apps;                 /* app_contexts for this job */
     int32_t                 num_apps;               /* number of app_contexts */
     orte_mapping_policy_t   policy;                 /* mapping policy */
+    int32_t                 npersocket;             /* number of ranks/socket */
     int16_t                 cpus_per_rank;          /* number of cpus/rank */
     int16_t                 stride;                 /* step size between cores of multi-core/rank procs */
     orte_job_controls_t     controls;               /* control flags for job */