diff options
| -rw-r--r-- | net/core/datagram.c | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c index 6f54d0a..eaa1d32 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -128,6 +128,35 @@ out_noerr: goto out; } +static int skb_set_peeked(struct sk_buff *skb) +{ + struct sk_buff *nskb; + + if (skb->peeked) + return 0; + + /* We have to unshare an skb before modifying it. */ + if (!skb_shared(skb)) + goto done; + + nskb = skb_clone(skb, GFP_ATOMIC); + if (!nskb) + return -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 0; +} + /** * __skb_recv_datagram - Receive a datagram skbuff * @sk: socket @@ -160,7 +189,9 @@ out_noerr: struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags, int *peeked, int *err) { + struct sk_buff_head *queue = &sk->sk_receive_queue; struct sk_buff *skb; + unsigned long cpu_flags; long timeo; /* * Caller is allowed not to check sk->sk_err before skb_recv_datagram() @@ -179,15 +210,16 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned 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; - spin_lock_irqsave(&queue->lock, cpu_flags); skb = skb_peek(queue); if (skb) { *peeked = skb->peeked; if (flags & MSG_PEEK) { - skb->peeked = 1; + + error = skb_set_peeked(skb); + if (error) + goto unlock_err; + atomic_inc(&skb->users); } else __skb_unlink(skb, queue); @@ -206,6 +238,8 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags, return NULL; +unlock_err: + spin_unlock_irqrestore(&queue->lock, cpu_flags); no_packet: *err = error; return NULL; |