1. Set segments length in prepare_src() after packing because actual size may be

smaller then allocated size.

2. If reserve zero don't allocate coalesced frag since it will be RDMAed, not
send.  The logic was other way around.

This commit was SVN r16928.

ompi/mca/btl/openib/btl_openib.c

@@ -785,8 +785,9 @@ mca_btl_base_descriptor_t* mca_btl_openib_prepare_src(
     }
   
     frag = (mca_btl_openib_com_frag_t*)(reserve ?
-            ib_frag_alloc(openib_btl, max_data + reserve, order, flags) :
-            mca_btl_openib_alloc(btl, endpoint, order, max_data, flags));
+            mca_btl_openib_alloc(btl, endpoint, order, max_data + reserve,
+                flags) :
+            ib_frag_alloc(openib_btl, max_data, order, flags));
 
     if(NULL == frag)
         return NULL;
@@ -798,6 +799,9 @@ mca_btl_base_descriptor_t* mca_btl_openib_prepare_src(
     
     *size = max_data;
 
+    /* not all upper layer users set this */
+    to_base_frag(frag)->segment.seg_len = max_data + reserve;
+
     return &to_base_frag(frag)->base;
 }