}
  
        /* We now decide whether we can put our special header into the sk_buff */
-       if (skb_cloned(skb) || skb_headroom(skb) < 2) {
-               /* no such luck - we make our own */
-               struct sk_buff *copied_skb;
-               copied_skb = skb_copy_expand(skb, 2, 0, GFP_ATOMIC);
-               dev_kfree_skb_irq(skb);
-               skb = copied_skb;
-               if (!copied_skb) {
-                       net->stats.tx_errors++;
-                       netif_start_queue(net);
-                       spin_unlock_irq(&kaweth->device_lock);
-                       return NETDEV_TX_OK;
-               }
+       if (skb_cow_head(skb, 2)) {
 -              kaweth->stats.tx_errors++;
++              net->stats.tx_errors++;
+               netif_start_queue(net);
+               spin_unlock_irq(&kaweth->device_lock);
+               dev_kfree_skb_any(skb);
+               return NETDEV_TX_OK;
        }
  
        private_header = (__le16 *)__skb_push(skb, 2);
 
                        return NULL;
                }
  
 -              return remove_monitor_info(local, origskb, rtap_vendor_space);
 +              remove_monitor_info(origskb, present_fcs_len,
 +                                  rtap_vendor_space);
 +              return origskb;
        }
  
+       ieee80211_handle_mu_mimo_mon(monitor_sdata, origskb, rtap_vendor_space);
+ 
        /* room for the radiotap header based on driver features */
        rt_hdrlen = ieee80211_rx_radiotap_hdrlen(local, status, origskb);
        needed_headroom = rt_hdrlen - rtap_vendor_space;