[infiniband] Allow completion queue operations to be optional

The send completion handler typically will just free the I/O buffer,
so allow this common case to be handled by the Infiniband core.

src/net/infiniband.c

  */
 void ib_complete_send ( struct ib_device *ibdev, struct ib_queue_pair *qp,
 			struct io_buffer *iobuf, int rc ) {
-	qp->send.cq->op->complete_send ( ibdev, qp, iobuf, rc );
+
+	if ( qp->send.cq->op->complete_send ) {
+		qp->send.cq->op->complete_send ( ibdev, qp, iobuf, rc );
+	} else {
+		free_iob ( iobuf );
+	}
 	qp->send.fill--;
 }
 
 void ib_complete_recv ( struct ib_device *ibdev, struct ib_queue_pair *qp,
 			struct ib_address_vector *av,
 			struct io_buffer *iobuf, int rc ) {
-	qp->recv.cq->op->complete_recv ( ibdev, qp, av, iobuf, rc );
+
+	if ( qp->recv.cq->op->complete_recv ) {
+		qp->recv.cq->op->complete_recv ( ibdev, qp, av, iobuf, rc );
+	} else {
+		free_iob ( iobuf );
+	}
 	qp->recv.fill--;
 }
 

src/net/infiniband/ib_gma.c

 	free_iob ( iobuf );
 }
 
-/**
- * Complete GMA send
- *
- *
- * @v ibdev		Infiniband device
- * @v qp		Queue pair
- * @v iobuf		I/O buffer
- * @v rc		Completion status code
- */
-static void ib_gma_complete_send ( struct ib_device *ibdev __unused,
-				   struct ib_queue_pair *qp,
-				   struct io_buffer *iobuf, int rc ) {
-	struct ib_gma *gma = ib_qp_get_ownerdata ( qp );
-
-	if ( rc != 0 ) {
-		DBGC ( gma, "GMA %p send completion error: %s\n",
-		       gma, strerror ( rc ) );
-	}
-	free_iob ( iobuf );
-}
-
 /** GMA completion operations */
 static struct ib_completion_queue_operations ib_gma_completion_ops = {
-	.complete_send = ib_gma_complete_send,
 	.complete_recv = ib_gma_complete_recv,
 };