Merge tag 'v3.10.90' into update

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / core / datagram.c

diff --git a/net/core/datagram.c b/net/core/datagram.c
index b71423db77851eed9bd91f06a6ac0630f967a3e5..052b71c5b1b4ce2864cf195357dda0ef787eb32a 100644 (file)
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -128,6 +128,35 @@ 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
@@ -162,7 +191,9 @@ 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()
@@ -181,8 +212,6 @@ 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;
@@ -196,7 +225,12 @@ 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);
@@ -216,6 +250,8 @@ 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;
@@ -665,7 +701,8 @@ __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
        if (likely(!sum)) {
                if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
                        netdev_rx_csum_fault(skb->dev);
-               skb->ip_summed = CHECKSUM_UNNECESSARY;
+               if (!skb_shared(skb))
+                       skb->ip_summed = CHECKSUM_UNNECESSARY;
        }
        return sum;
 }