[ipoib] Attempt the broadcast group join only if the link is up

Attempting the broadcast group join while the link is down is
harmless, but can generate annoying volumes of debug messages.

src/drivers/net/ipoib.c

@@ -535,17 +535,11 @@ static int ipoib_open ( struct net_device *netdev ) {
 	/* Fill receive rings */
 	ib_refill_recv ( ibdev, ipoib->qp );
 
-	/* Join broadcast group */
-	if ( ( rc = ipoib_join_broadcast_group ( ipoib ) ) != 0 ) {
-		DBGC ( ipoib, "IPoIB %p could not join broadcast group: %s\n",
-		       ipoib, strerror ( rc ) );
-		goto err_join_broadcast;
-	}
+	/* Fake a link status change to join the broadcast group */
+	ipoib_link_state_changed ( ibdev );
 
 	return 0;
 
-	ipoib_leave_broadcast_group ( ipoib );
- err_join_broadcast:
 	ib_destroy_qp ( ibdev, ipoib->qp );
  err_create_qp:
 	ib_destroy_cq ( ibdev, ipoib->cq );
@@ -639,7 +633,8 @@ void ipoib_link_state_changed ( struct ib_device *ibdev ) {
 	ipoib_set_ib_params ( ipoib );
 
 	/* Join new broadcast group */
-	if ( ( rc = ipoib_join_broadcast_group ( ipoib ) ) != 0 ) {
+	if ( ib_link_ok ( ibdev ) &&
+	     ( ( rc = ipoib_join_broadcast_group ( ipoib ) ) != 0 ) ) {
 		DBGC ( ipoib, "IPoIB %p could not rejoin broadcast group: "
 		       "%s\n", ipoib, strerror ( rc ) );
 		return;