Merge pull request #3833 from yosefe/topic/pml-yalla-dt-size-fix

pml/yalla: fix getting size of a continuous type.

ompi/mca/pml/yalla/pml_yalla_datatype.h

@@ -26,14 +26,13 @@ OBJ_CLASS_DECLARATION(mca_pml_yalla_convertor_t);
 
 #define PML_YALLA_INIT_MXM_REQ_DATA(_req_base, _buf, _count, _dtype, _stream_type, ...) \
     { \
-        size_t size; \
-        ptrdiff_t lb; \
+        ptrdiff_t span, gap; \
         \
         if (opal_datatype_is_contiguous_memory_layout(&(_dtype)->super, _count)) { \
-            ompi_datatype_get_true_extent(_dtype, &lb, &size); \
+            span = opal_datatype_span(&(_dtype)->super, (_count), &gap); \
             (_req_base)->data_type          = MXM_REQ_DATA_BUFFER; \
-            (_req_base)->data.buffer.ptr    = (char *)_buf + lb; \
-            (_req_base)->data.buffer.length = size * (_count); \
+            (_req_base)->data.buffer.ptr    = (char *)_buf + gap; \
+            (_req_base)->data.buffer.length = span; \
         } else { \
             mca_pml_yalla_set_noncontig_data_ ## _stream_type(_req_base, \
                                                               _buf, _count, \