X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?p=kvmfornfv.git;a=blobdiff_plain;f=kernel%2Fnet%2Fcore%2Fdatagram.c;h=617088aee21d41ba98d4ef5ebee5d6c002efe029;hp=b80fb91bb3f7e8dc630663cb5e012dc97ac6924f;hb=ec0a2ed6d8a5e555edef907895c041e285fdb495;hpb=342fa5dfa053559f47caad657132522496dcf1b3

diff --git a/kernel/net/core/datagram.c b/kernel/net/core/datagram.c
index b80fb91bb..617088aee 100644
--- 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;
 }