These changes are a raw update to a vanilla kernel 4.1.10, with the

[kvmfornfv.git] / kernel / net / core / datagram.c

diff --git a/kernel/net/core/datagram.c b/kernel/net/core/datagram.c
index b80fb91..617088a 100644 (file)
--- a/kernel/net/core/datagram.c
+++ b/kernel/net/core/datagram.c
@@ -131,6 +131,35 @@ out_noerr:
        goto out;
 }
 
+static struct sk_buff *skb_set_peeked(struct sk_buff *skb)
+{
+       struct sk_buff *nskb;
+
+       if (skb->peeked)
+               return skb;
+
+       /* We have to unshare an skb before modifying it. */
+       if (!skb_shared(skb))
+               goto done;
+
+       nskb = skb_clone(skb, GFP_ATOMIC);
+       if (!nskb)
+               return ERR_PTR(-ENOMEM);
+
+       skb->prev->next = nskb;
+       skb->next->prev = nskb;
+       nskb->prev = skb->prev;
+       nskb->next = skb->next;
+
+       consume_skb(skb);
+       skb = nskb;
+
+done:
+       skb->peeked = 1;
+
+       return skb;
+}
+
 /**
  *     __skb_recv_datagram - Receive a datagram skbuff
  *     @sk: socket
@@ -165,7 +194,9 @@ out_noerr:
 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags,
                                    int *peeked, int *off, int *err)
 {
+       struct sk_buff_head *queue = &sk->sk_receive_queue;
        struct sk_buff *skb, *last;
+       unsigned long cpu_flags;
        long timeo;
        /*
         * Caller is allowed not to check sk->sk_err before skb_recv_datagram()
@@ -184,8 +215,6 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags,
                 * Look at current nfs client by the way...
                 * However, this function was correct in any case. 8)
                 */
-               unsigned long cpu_flags;
-               struct sk_buff_head *queue = &sk->sk_receive_queue;
                int _off = *off;
 
                last = (struct sk_buff *)queue;
@@ -199,7 +228,12 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags,
                                        _off -= skb->len;
                                        continue;
                                }
-                               skb->peeked = 1;
+
+                               skb = skb_set_peeked(skb);
+                               error = PTR_ERR(skb);
+                               if (IS_ERR(skb))
+                                       goto unlock_err;
+
                                atomic_inc(&skb->users);
                        } else
                                __skb_unlink(skb, queue);
@@ -223,6 +257,8 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags,
 
        return NULL;
 
+unlock_err:
+       spin_unlock_irqrestore(&queue->lock, cpu_flags);
 no_packet:
        *err = error;
        return NULL;
@@ -622,7 +658,8 @@ __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
                    !skb->csum_complete_sw)
                        netdev_rx_csum_fault(skb->dev);
        }
-       skb->csum_valid = !sum;
+       if (!skb_shared(skb))
+               skb->csum_valid = !sum;
        return sum;
 }
 EXPORT_SYMBOL(__skb_checksum_complete_head);
@@ -642,11 +679,13 @@ __sum16 __skb_checksum_complete(struct sk_buff *skb)
                        netdev_rx_csum_fault(skb->dev);
        }
 
-       /* Save full packet checksum */
-       skb->csum = csum;
-       skb->ip_summed = CHECKSUM_COMPLETE;
-       skb->csum_complete_sw = 1;
-       skb->csum_valid = !sum;
+       if (!skb_shared(skb)) {
+               /* Save full packet checksum */
+               skb->csum = csum;
+               skb->ip_summed = CHECKSUM_COMPLETE;
+               skb->csum_complete_sw = 1;
+               skb->csum_valid = !sum;
+       }
 
        return sum;
 }