Merge pull request open-mpi#8471 from hjelmn/btl_vader_allow_null_cbfunc_for_btl_send

btl/sm: do not set always callback frag when there is none

Author: hjelmn

opal/mca/btl/sm/btl_sm_send.c

@@ -14,6 +14,7 @@
  * Copyright (c) 2009      Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2010-2014 Los Alamos National Security, LLC. All rights
  *                         reserved.
+ * Copyright (c) 2021      Google, LLC. All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -42,18 +43,25 @@ int mca_btl_sm_send (struct mca_btl_base_module_t *btl,
     mca_btl_sm_frag_t *frag = (mca_btl_sm_frag_t *) descriptor;
     const size_t total_size = frag->segments[0].seg_len;
 
-    /* in order to work around a long standing ob1 bug (see #3845) we have to always
-     * make the callback. once this is fixed in ob1 we can restore the code below. */
-    frag->base.des_flags |= MCA_BTL_DES_SEND_ALWAYS_CALLBACK;
+    if (frag->base.des_cbfunc) {
+        /* in order to work around a long standing ob1 bug (see #3845) we have to always
+         * make the callback. once this is fixed in ob1 we can restore the code below. */
+        frag->base.des_flags |= MCA_BTL_DES_SEND_ALWAYS_CALLBACK;
+    }
 
     /* header (+ optional inline data) */
     frag->hdr->len = total_size;
     /* type of message, pt-2-pt, one-sided, etc */
     frag->hdr->tag = tag;
 
+    /* clear the complete flag if it has been set */
+    frag->hdr->flags &= ~MCA_BTL_SM_FLAG_COMPLETE;
+
     /* post the relative address of the descriptor into the peer's fifo */
     if (opal_list_get_size (&endpoint->pending_frags) || !sm_fifo_write_ep (frag->hdr, endpoint)) {
-        frag->base.des_flags |= MCA_BTL_DES_SEND_ALWAYS_CALLBACK;
+        if (frag->base.des_cbfunc) {
+            frag->base.des_flags |= MCA_BTL_DES_SEND_ALWAYS_CALLBACK;
+        }
         OPAL_THREAD_LOCK(&endpoint->pending_frags_lock);
         opal_list_append (&endpoint->pending_frags, (opal_list_item_t *) frag);
         if (!endpoint->waiting) {
@@ -69,8 +77,9 @@ int mca_btl_sm_send (struct mca_btl_base_module_t *btl,
     return OPAL_SUCCESS;
 
 #if 0
-    if ((frag->hdr->flags & MCA_BTL_SM_FLAG_SINGLE_COPY) ||
-        !(frag->base.des_flags & MCA_BTL_DES_FLAGS_BTL_OWNERSHIP)) {
+    if (((frag->hdr->flags & MCA_BTL_SM_FLAG_SINGLE_COPY) ||
+        !(frag->base.des_flags & MCA_BTL_DES_FLAGS_BTL_OWNERSHIP)) &&
+        frag->base.des_cbfunc) {
         frag->base.des_flags |= MCA_BTL_DES_SEND_ALWAYS_CALLBACK;
 
         return OPAL_SUCCESS;