1 files changed, 16 insertions, 11 deletions

diff --git a/net/core/datagram.c b/net/core/datagram.c
index 68bbf9f65cb0..e4fbfd6e2bd4 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -37,7 +37,6 @@
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <asm/uaccess.h>
-#include <asm/system.h>
 #include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/errno.h>
@@ -132,6 +131,8 @@ out_noerr:
  *	__skb_recv_datagram - Receive a datagram skbuff
  *	@sk: socket
  *	@flags: MSG_ flags
+ *	@off: an offset in bytes to peek skb from. Returns an offset
+ *	      within an skb where data actually starts
  *	@peeked: returns non-zero if this packet has been seen before
  *	@err: error code returned
  *
@@ -158,7 +159,7 @@ out_noerr:
  *	the standard around please.
  */
 struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
-				    int *peeked, int *err)
+				    int *peeked, int *off, int *err)
 {
 	struct sk_buff *skb;
 	long timeo;
@@ -180,21 +181,25 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
 		 * 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(&sk->sk_receive_queue.lock, cpu_flags);
-		skb = skb_peek(&sk->sk_receive_queue);
-		if (skb) {
+		spin_lock_irqsave(&queue->lock, cpu_flags);
+		skb_queue_walk(queue, skb) {
 			*peeked = skb->peeked;
 			if (flags & MSG_PEEK) {
+				if (*off >= skb->len) {
+					*off -= skb->len;
+					continue;
+				}
 				skb->peeked = 1;
 				atomic_inc(&skb->users);
 			} else
-				__skb_unlink(skb, &sk->sk_receive_queue);
-		}
-		spin_unlock_irqrestore(&sk->sk_receive_queue.lock, cpu_flags);
+				__skb_unlink(skb, queue);
 
-		if (skb)
+			spin_unlock_irqrestore(&queue->lock, cpu_flags);
 			return skb;
+		}
+		spin_unlock_irqrestore(&queue->lock, cpu_flags);
 
 		/* User doesn't want to wait */
 		error = -EAGAIN;
@@ -214,10 +219,10 @@ EXPORT_SYMBOL(__skb_recv_datagram);
 struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
 				  int noblock, int *err)
 {
-	int peeked;
+	int peeked, off = 0;
 
 	return __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
-				   &peeked, err);
+				   &peeked, &off, err);
 }
 EXPORT_SYMBOL(skb_recv_datagram);