Fix for buglet #1423.

Any non-blocking P2P function should set the request to something else
then MPI_REQUEST_NULL, when passed a source/dest of MPI_PROC_NULL.

Introduce a new ompi_request_empty, which returns the
MPI_SOURCE=MPI_PROC_NULL, MPI_TAG=MPI_ANY_TAG, count=0 as specified by
the MPI-standard.

This commit was SVN r6611.

ompi/mpi/c/bsend_init.c

@@ -37,7 +37,7 @@ int MPI_Bsend_init(void *buf, int count, MPI_Datatype type,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
     

ompi/mpi/c/ibsend.c

@@ -38,7 +38,7 @@ int MPI_Ibsend(void *buf, int count, MPI_Datatype type, int dest,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/mpi/c/irecv.c

@@ -37,7 +37,7 @@ int MPI_Irecv(void *buf, int count, MPI_Datatype type, int source,
 {
     int rc;
     if (source == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return OMPI_SUCCESS;
     }
 

ompi/mpi/c/irsend.c

@@ -37,7 +37,7 @@ int MPI_Irsend(void *buf, int count, MPI_Datatype type, int dest,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/mpi/c/isend.c

@@ -37,7 +37,7 @@ int MPI_Isend(void *buf, int count, MPI_Datatype type, int dest,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/mpi/c/issend.c

@@ -38,7 +38,7 @@ int MPI_Issend(void *buf, int count, MPI_Datatype type, int dest,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/mpi/c/recv_init.c

@@ -37,7 +37,7 @@ int MPI_Recv_init(void *buf, int count, MPI_Datatype type, int source,
 {
     int rc;
     if (source == MPI_PROC_NULL) { 
-        *request = &ompi_request_null;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/mpi/c/rsend_init.c

@@ -38,7 +38,7 @@ int MPI_Rsend_init(void *buf, int count, MPI_Datatype type,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/mpi/c/send_init.c

@@ -38,7 +38,7 @@ int MPI_Send_init(void *buf, int count, MPI_Datatype type,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/mpi/c/ssend_init.c

@@ -38,7 +38,7 @@ int MPI_Ssend_init(void *buf, int count, MPI_Datatype type,
 {
     int rc;
     if (dest == MPI_PROC_NULL) {
-        *request = MPI_REQUEST_NULL;
+        *request = &ompi_request_empty;
         return MPI_SUCCESS;
     }
 

ompi/request/request.c

@@ -26,6 +26,7 @@ int                   ompi_request_poll_iterations = 20000;
 OMPI_DECLSPEC opal_mutex_t          ompi_request_lock;
 OMPI_DECLSPEC opal_condition_t      ompi_request_cond;
 OMPI_DECLSPEC ompi_request_t        ompi_request_null;
+OMPI_DECLSPEC ompi_request_t        ompi_request_empty;
 ompi_status_public_t  ompi_status_empty;
 
 
@@ -67,6 +68,7 @@ int ompi_request_init(void)
     OBJ_CONSTRUCT(&ompi_request_lock, opal_mutex_t);
     OBJ_CONSTRUCT(&ompi_request_cond, opal_condition_t);
     OBJ_CONSTRUCT(&ompi_request_null, ompi_request_t);
+    OBJ_CONSTRUCT(&ompi_request_empty, ompi_request_t);
 
     ompi_request_null.req_status.MPI_SOURCE = MPI_PROC_NULL;
     ompi_request_null.req_status.MPI_TAG = MPI_ANY_TAG;
@@ -87,6 +89,33 @@ int ompi_request_init(void)
         return OMPI_ERR_REQUEST;
     }
 
+    /* We need a way to distinguish between the user provided
+     * MPI_REQUEST_NULL to MPI_Wait* and a non-active (MPI_PROC_NULL)
+     * request passed to any P2P non-blocking function.
+     *
+     * The main difference to ompi_request_null is
+     * req_state being OMPI_REQUEST_ACTIVE, so that MPI_Waitall
+     * does not set the status to ompi_status_empty.
+     */
+    ompi_request_empty.req_status.MPI_SOURCE = MPI_PROC_NULL;
+    ompi_request_empty.req_status.MPI_TAG = MPI_ANY_TAG;
+    ompi_request_empty.req_status.MPI_ERROR = MPI_SUCCESS;
+    ompi_request_empty.req_status._count = 0;
+    ompi_request_empty.req_status._cancelled = 0;
+
+    ompi_request_empty.req_state = OMPI_REQUEST_ACTIVE;
+    ompi_request_empty.req_complete = true;
+    ompi_request_empty.req_type = OMPI_REQUEST_NULL;
+    ompi_request_empty.req_fini = ompi_request_null_free;
+    ompi_request_empty.req_free = ompi_request_null_free;
+    ompi_request_empty.req_cancel = ompi_request_null_cancel;
+    ompi_request_empty.req_f_to_c_index =
+        ompi_pointer_array_add(&ompi_request_f_to_c_table, &ompi_request_empty);
+
+    if (1 != ompi_request_empty.req_f_to_c_index) {
+        return OMPI_ERR_REQUEST;
+    }
+
     ompi_status_empty.MPI_SOURCE = MPI_ANY_SOURCE;
     ompi_status_empty.MPI_TAG = MPI_ANY_TAG;
     ompi_status_empty.MPI_ERROR = MPI_SUCCESS;

ompi/request/request.h

@@ -142,6 +142,7 @@ OMPI_DECLSPEC extern opal_mutex_t          ompi_request_lock;
 OMPI_DECLSPEC extern opal_condition_t      ompi_request_cond;
 OMPI_DECLSPEC extern int                   ompi_request_poll_iterations;
 OMPI_DECLSPEC extern ompi_request_t        ompi_request_null;
+OMPI_DECLSPEC extern ompi_request_t        ompi_request_empty;
 OMPI_DECLSPEC extern ompi_status_public_t  ompi_status_empty;