This reverts commit 
afe1de664ef3cb756e70938d99417dcbc6b1379a.
The series of IPoIB bug fixes that went into 3.19-rc1 introduce
regressions, and after trying to sort things out, we decided to revert
to 3.18's IPoIB driver and get things right for 3.20.
Signed-off-by: Roland Dreier <roland@purestorage.com>
 
                spin_unlock_irq(&priv->lock);
                priv->tx_wr.wr.ud.remote_qkey = priv->qkey;
                set_qkey = 1;
+
+               if (!ipoib_cm_admin_enabled(dev)) {
+                       rtnl_lock();
+                       dev_set_mtu(dev, min(priv->mcast_mtu, priv->admin_mtu));
+                       rtnl_unlock();
+               }
        }
 
        if (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
        }
 
        rtnl_lock();
-       if (!ipoib_cm_admin_enabled(priv->dev))
-               dev_set_mtu(priv->dev, min(priv->mcast_mtu, priv->admin_mtu));
        netif_carrier_on(priv->dev);
        rtnl_unlock();
 }