Allow MPI_ANY_SOURCE in MPI_Sendrecv_replace.

Signed-off-by: George Bosilca <bosilca@icl.utk.edu>

ompi/mpi/c/sendrecv_replace.c

@@ -2,7 +2,7 @@
  * Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
- * Copyright (c) 2004-2010 The University of Tennessee and The University
+ * Copyright (c) 2004-2017 The University of Tennessee and The University
  *                         of Tennessee Research Foundation.  All rights
  *                         reserved.
  * Copyright (c) 2004-2008 High Performance Computing Center Stuttgart,
@@ -80,15 +80,24 @@ int MPI_Sendrecv_replace(void * buf, int count, MPI_Datatype datatype,
 
         OPAL_CR_EXIT_LIBRARY();
         return rc;
-    } else {
+    }
 
+    /**
+     * If we look for an optimal solution, then we should receive the data into a temporary buffer
+     * and once the send completes we would unpack back into the original buffer. However, if the
+     * sender is unknown, this approach can only be implementing by receiving with the recv datatype
+     * (potentially non-contiguous) and thus the allocated memory will be larger than the size of the
+     * datatype. A simpler, but potentially less efficient approach is to work on the data we have
+     * control of, aka the sent data, and pack it into a contiguous buffer before posting the receive.
+     * Once the send completes, we free it.
+     */
     opal_convertor_t convertor;
-        struct iovec iov;
+    unsigned char packed_data[2048];
-        unsigned char recv_data[2048];
+    struct iovec iov = { .iov_base = packed_data, .iov_len = sizeof(packed_data) };
     size_t packed_size, max_data;
     uint32_t iov_count;
     ompi_status_public_t recv_status;
-        ompi_proc_t* proc = ompi_comm_peer_lookup(comm,source);
+    ompi_proc_t* proc = ompi_comm_peer_lookup(comm, dest);
     if(proc == NULL) {
         rc = MPI_ERR_RANK;
         OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);
@@ -96,48 +105,38 @@ int MPI_Sendrecv_replace(void * buf, int count, MPI_Datatype datatype,
 
     /* initialize convertor to unpack recv buffer */
     OBJ_CONSTRUCT(&convertor, opal_convertor_t);
-        opal_convertor_copy_and_prepare_for_recv( proc->super.proc_convertor, &(datatype->super),
+    opal_convertor_copy_and_prepare_for_send( proc->super.proc_convertor, &(datatype->super),
                                               count, buf, 0, &convertor );
 
     /* setup a buffer for recv */
     opal_convertor_get_packed_size( &convertor, &packed_size );
-        if( packed_size > sizeof(recv_data) ) {
+    if( packed_size > sizeof(packed_data) ) {
         rc = PMPI_Alloc_mem(packed_size, MPI_INFO_NULL, &iov.iov_base);
         if(OMPI_SUCCESS != rc) {
-                OMPI_ERRHANDLER_RETURN(OMPI_ERR_OUT_OF_RESOURCE, comm, MPI_ERR_BUFFER, FUNC_NAME);
+            rc = OMPI_ERR_OUT_OF_RESOURCE;
+            goto cleanup_and_return;
         }
-        } else {
-            iov.iov_base = (caddr_t)recv_data;
     }
+    max_data = packed_size;
+    iov_count = 1;
+    rc = opal_convertor_pack(&convertor, &iov, &iov_count, &max_data);
     
     /* recv into temporary buffer */
-        rc = PMPI_Sendrecv( buf, count, datatype, dest, sendtag, iov.iov_base, packed_size,
+    rc = PMPI_Sendrecv( iov.iov_base, packed_size, MPI_PACKED, dest, sendtag, buf, count,
-                           MPI_BYTE, source, recvtag, comm, &recv_status );
+                        datatype, source, recvtag, comm, &recv_status );
-        if (rc != MPI_SUCCESS) {
-            if(packed_size > sizeof(recv_data))
-                PMPI_Free_mem(iov.iov_base);
-            OBJ_DESTRUCT(&convertor);
-            OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);
-        }
-
-        /* unpack into users buffer */
-        iov.iov_len = recv_status._ucount;
-        iov_count = 1;
-        max_data = recv_status._ucount;
-        opal_convertor_unpack(&convertor, &iov, &iov_count, &max_data );
 
+ cleanup_and_return:
     /* return status to user */
     if(status != MPI_STATUS_IGNORE) {
         *status = recv_status;
     }
 
     /* release resources */
-        if(packed_size > sizeof(recv_data)) {
+    if(packed_size > sizeof(packed_data)) {
         PMPI_Free_mem(iov.iov_base);
     }
     OBJ_DESTRUCT(&convertor);
 
     OPAL_CR_EXIT_LIBRARY();
-        return MPI_SUCCESS;
+    OMPI_ERRHANDLER_RETURN(rc, comm, rc, FUNC_NAME);
-    }
 }