Merge branch '20120221_isdn' of git://repo.or.cz/linux-2.6/trivial-mods
diff --git a/arch/alpha/include/asm/socket.h b/arch/alpha/include/asm/socket.h
index 082355f..16449d3 100644
--- a/arch/alpha/include/asm/socket.h
+++ b/arch/alpha/include/asm/socket.h
@@ -71,6 +71,7 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 /* O_NONBLOCK clashes with the bits used for socket types.  Therefore we
  * have to define SOCK_NONBLOCK to a different value here.
diff --git a/arch/arm/include/asm/socket.h b/arch/arm/include/asm/socket.h
index dec6f9a..d958c74 100644
--- a/arch/arm/include/asm/socket.h
+++ b/arch/arm/include/asm/socket.h
@@ -64,5 +64,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/avr32/include/asm/socket.h b/arch/avr32/include/asm/socket.h
index 247b88c..30078f9 100644
--- a/arch/avr32/include/asm/socket.h
+++ b/arch/avr32/include/asm/socket.h
@@ -64,5 +64,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* __ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/asm/socket.h b/arch/cris/include/asm/socket.h
index e269264..048aba6 100644
--- a/arch/cris/include/asm/socket.h
+++ b/arch/cris/include/asm/socket.h
@@ -66,6 +66,7 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/frv/include/asm/socket.h b/arch/frv/include/asm/socket.h
index ce80fda..7a361810f3 100644
--- a/arch/frv/include/asm/socket.h
+++ b/arch/frv/include/asm/socket.h
@@ -64,6 +64,7 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/h8300/include/asm/socket.h b/arch/h8300/include/asm/socket.h
index cf1daab..e7bbfce 100644
--- a/arch/h8300/include/asm/socket.h
+++ b/arch/h8300/include/asm/socket.h
@@ -64,5 +64,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/ia64/include/asm/socket.h b/arch/ia64/include/asm/socket.h
index 4b03664..ced62de 100644
--- a/arch/ia64/include/asm/socket.h
+++ b/arch/ia64/include/asm/socket.h
@@ -73,5 +73,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/asm/socket.h b/arch/m32r/include/asm/socket.h
index e8b8c5b..696cb4c 100644
--- a/arch/m32r/include/asm/socket.h
+++ b/arch/m32r/include/asm/socket.h
@@ -64,5 +64,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/m68k/include/asm/socket.h b/arch/m68k/include/asm/socket.h
index d4708ce..e8b41a6 100644
--- a/arch/m68k/include/asm/socket.h
+++ b/arch/m68k/include/asm/socket.h
@@ -64,5 +64,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/mips/include/asm/socket.h b/arch/mips/include/asm/socket.h
index ad5c0a7..5210487 100644
--- a/arch/mips/include/asm/socket.h
+++ b/arch/mips/include/asm/socket.h
@@ -84,6 +84,7 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #ifdef __KERNEL__
 
diff --git a/arch/mn10300/include/asm/socket.h b/arch/mn10300/include/asm/socket.h
index 876356d..013fcc5 100644
--- a/arch/mn10300/include/asm/socket.h
+++ b/arch/mn10300/include/asm/socket.h
@@ -64,5 +64,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/asm/socket.h b/arch/parisc/include/asm/socket.h
index d28c51b..f717c9b 100644
--- a/arch/parisc/include/asm/socket.h
+++ b/arch/parisc/include/asm/socket.h
@@ -63,6 +63,7 @@
 
 #define SO_WIFI_STATUS		0x4022
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		0x4023
 
 /* O_NONBLOCK clashes with the bits used for socket types.  Therefore we
  * have to define SOCK_NONBLOCK to a different value here.
diff --git a/arch/powerpc/include/asm/socket.h b/arch/powerpc/include/asm/socket.h
index 2fc2af8..fe1c0b4 100644
--- a/arch/powerpc/include/asm/socket.h
+++ b/arch/powerpc/include/asm/socket.h
@@ -71,5 +71,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif	/* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/asm/socket.h b/arch/s390/include/asm/socket.h
index 67b5c1b..581702f 100644
--- a/arch/s390/include/asm/socket.h
+++ b/arch/s390/include/asm/socket.h
@@ -72,5 +72,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/asm/socket.h b/arch/sparc/include/asm/socket.h
index 8af1b64..68e2e27 100644
--- a/arch/sparc/include/asm/socket.h
+++ b/arch/sparc/include/asm/socket.h
@@ -60,6 +60,7 @@
 
 #define SO_WIFI_STATUS		0x0025
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		0x0026
 
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION		0x5001
diff --git a/arch/xtensa/include/asm/socket.h b/arch/xtensa/include/asm/socket.h
index bb06968..74818b1 100644
--- a/arch/xtensa/include/asm/socket.h
+++ b/arch/xtensa/include/asm/socket.h
@@ -75,5 +75,6 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS		SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 
 #endif	/* _XTENSA_SOCKET_H */
diff --git a/include/asm-generic/socket.h b/include/asm-generic/socket.h
index 49c1704..d9aaac0 100644
--- a/include/asm-generic/socket.h
+++ b/include/asm-generic/socket.h
@@ -67,4 +67,5 @@
 
 #define SO_WIFI_STATUS		41
 #define SCM_WIFI_STATUS	SO_WIFI_STATUS
+#define SO_PEEK_OFF		42
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/include/linux/net.h b/include/linux/net.h
index b299230..be60c7f 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -206,6 +206,7 @@
 				      int offset, size_t size, int flags);
 	ssize_t 	(*splice_read)(struct socket *sock,  loff_t *ppos,
 				       struct pipe_inode_info *pipe, size_t len, unsigned int flags);
+	void		(*set_peek_off)(struct sock *sk, int val);
 };
 
 #define DECLARE_SOCKADDR(type, dst, src)	\
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2b7317f..c11a44e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -877,6 +877,24 @@
 }
 
 /**
+ *	skb_peek_next - peek skb following the given one from a queue
+ *	@skb: skb to start from
+ *	@list_: list to peek at
+ *
+ *	Returns %NULL when the end of the list is met or a pointer to the
+ *	next element. The reference count is not incremented and the
+ *	reference is therefore volatile. Use with caution.
+ */
+static inline struct sk_buff *skb_peek_next(struct sk_buff *skb,
+		const struct sk_buff_head *list_)
+{
+	struct sk_buff *next = skb->next;
+	if (next == (struct sk_buff *)list_)
+		next = NULL;
+	return next;
+}
+
+/**
  *	skb_peek_tail - peek at the tail of an &sk_buff_head
  *	@list_: list to peek at
  *
@@ -2046,7 +2064,7 @@
 	for (iter = skb_shinfo(skb)->frag_list; iter; iter = iter->next)
 
 extern struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned flags,
-					   int *peeked, int *err);
+					   int *peeked, int *off, int *err);
 extern struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
 					 int noblock, int *err);
 extern unsigned int    datagram_poll(struct file *file, struct socket *sock,
diff --git a/include/net/sock.h b/include/net/sock.h
index 91c1c8b..9c0553b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -357,6 +357,7 @@
 	struct page		*sk_sndmsg_page;
 	struct sk_buff		*sk_send_head;
 	__u32			sk_sndmsg_off;
+	__s32			sk_peek_off;
 	int			sk_write_pending;
 #ifdef CONFIG_SECURITY
 	void			*sk_security;
@@ -373,6 +374,30 @@
 	void                    (*sk_destruct)(struct sock *sk);
 };
 
+static inline int sk_peek_offset(struct sock *sk, int flags)
+{
+	if ((flags & MSG_PEEK) && (sk->sk_peek_off >= 0))
+		return sk->sk_peek_off;
+	else
+		return 0;
+}
+
+static inline void sk_peek_offset_bwd(struct sock *sk, int val)
+{
+	if (sk->sk_peek_off >= 0) {
+		if (sk->sk_peek_off >= val)
+			sk->sk_peek_off -= val;
+		else
+			sk->sk_peek_off = 0;
+	}
+}
+
+static inline void sk_peek_offset_fwd(struct sock *sk, int val)
+{
+	if (sk->sk_peek_off >= 0)
+		sk->sk_peek_off += val;
+}
+
 /*
  * Hashed lists helper routines
  */
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 68bbf9f..d3cf12f 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -132,6 +132,8 @@
  *	__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 +160,7 @@
  *	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 +182,25 @@
 		 * 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 +220,10 @@
 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);
 
diff --git a/net/core/sock.c b/net/core/sock.c
index 02f8dfe..19942d4 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -793,6 +793,12 @@
 		sock_valbool_flag(sk, SOCK_WIFI_STATUS, valbool);
 		break;
 
+	case SO_PEEK_OFF:
+		if (sock->ops->set_peek_off)
+			sock->ops->set_peek_off(sk, val);
+		else
+			ret = -EOPNOTSUPP;
+		break;
 	default:
 		ret = -ENOPROTOOPT;
 		break;
@@ -1018,6 +1024,12 @@
 		v.val = !!sock_flag(sk, SOCK_WIFI_STATUS);
 		break;
 
+	case SO_PEEK_OFF:
+		if (!sock->ops->set_peek_off)
+			return -EOPNOTSUPP;
+
+		v.val = sk->sk_peek_off;
+		break;
 	default:
 		return -ENOPROTOOPT;
 	}
@@ -2092,6 +2104,7 @@
 
 	sk->sk_sndmsg_page	=	NULL;
 	sk->sk_sndmsg_off	=	0;
+	sk->sk_peek_off		=	-1;
 
 	sk->sk_peer_pid 	=	NULL;
 	sk->sk_peer_cred	=	NULL;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index cd99f1a..7c41ab8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1167,7 +1167,7 @@
 	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
 	struct sk_buff *skb;
 	unsigned int ulen, copied;
-	int peeked;
+	int peeked, off = 0;
 	int err;
 	int is_udplite = IS_UDPLITE(sk);
 	bool slow;
@@ -1183,7 +1183,7 @@
 
 try_again:
 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
-				  &peeked, &err);
+				  &peeked, &off, &err);
 	if (!skb)
 		goto out;
 
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 8aebf8f..37b0699 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -342,7 +342,7 @@
 	struct inet_sock *inet = inet_sk(sk);
 	struct sk_buff *skb;
 	unsigned int ulen, copied;
-	int peeked;
+	int peeked, off = 0;
 	int err;
 	int is_udplite = IS_UDPLITE(sk);
 	int is_udp4;
@@ -359,7 +359,7 @@
 
 try_again:
 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
-				  &peeked, &err);
+				  &peeked, &off, &err);
 	if (!skb)
 		goto out;
 
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 85d3bb7..0be4d24 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -530,6 +530,16 @@
 static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
 				  struct msghdr *, size_t, int);
 
+static void unix_set_peek_off(struct sock *sk, int val)
+{
+	struct unix_sock *u = unix_sk(sk);
+
+	mutex_lock(&u->readlock);
+	sk->sk_peek_off = val;
+	mutex_unlock(&u->readlock);
+}
+
+
 static const struct proto_ops unix_stream_ops = {
 	.family =	PF_UNIX,
 	.owner =	THIS_MODULE,
@@ -549,6 +559,7 @@
 	.recvmsg =	unix_stream_recvmsg,
 	.mmap =		sock_no_mmap,
 	.sendpage =	sock_no_sendpage,
+	.set_peek_off =	unix_set_peek_off,
 };
 
 static const struct proto_ops unix_dgram_ops = {
@@ -570,6 +581,7 @@
 	.recvmsg =	unix_dgram_recvmsg,
 	.mmap =		sock_no_mmap,
 	.sendpage =	sock_no_sendpage,
+	.set_peek_off =	unix_set_peek_off,
 };
 
 static const struct proto_ops unix_seqpacket_ops = {
@@ -591,6 +603,7 @@
 	.recvmsg =	unix_seqpacket_recvmsg,
 	.mmap =		sock_no_mmap,
 	.sendpage =	sock_no_sendpage,
+	.set_peek_off =	unix_set_peek_off,
 };
 
 static struct proto unix_proto = {
@@ -1756,6 +1769,7 @@
 	int noblock = flags & MSG_DONTWAIT;
 	struct sk_buff *skb;
 	int err;
+	int peeked, skip;
 
 	err = -EOPNOTSUPP;
 	if (flags&MSG_OOB)
@@ -1769,7 +1783,9 @@
 		goto out;
 	}
 
-	skb = skb_recv_datagram(sk, flags, noblock, &err);
+	skip = sk_peek_offset(sk, flags);
+
+	skb = __skb_recv_datagram(sk, flags, &peeked, &skip, &err);
 	if (!skb) {
 		unix_state_lock(sk);
 		/* Signal EOF on disconnected non-blocking SEQPACKET socket. */
@@ -1786,12 +1802,12 @@
 	if (msg->msg_name)
 		unix_copy_addr(msg, skb->sk);
 
-	if (size > skb->len)
-		size = skb->len;
-	else if (size < skb->len)
+	if (size > skb->len - skip)
+		size = skb->len - skip;
+	else if (size < skb->len - skip)
 		msg->msg_flags |= MSG_TRUNC;
 
-	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, size);
+	err = skb_copy_datagram_iovec(skb, skip, msg->msg_iov, size);
 	if (err)
 		goto out_free;
 
@@ -1808,6 +1824,8 @@
 	if (!(flags & MSG_PEEK)) {
 		if (UNIXCB(skb).fp)
 			unix_detach_fds(siocb->scm, skb);
+
+		sk_peek_offset_bwd(sk, skb->len);
 	} else {
 		/* It is questionable: on PEEK we could:
 		   - do not return fds - good, but too simple 8)
@@ -1821,6 +1839,9 @@
 		   clearly however!
 
 		*/
+
+		sk_peek_offset_fwd(sk, size);
+
 		if (UNIXCB(skb).fp)
 			siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
 	}
@@ -1884,6 +1905,7 @@
 	int target;
 	int err = 0;
 	long timeo;
+	int skip;
 
 	err = -EINVAL;
 	if (sk->sk_state != TCP_ESTABLISHED)
@@ -1913,12 +1935,15 @@
 		goto out;
 	}
 
+	skip = sk_peek_offset(sk, flags);
+
 	do {
 		int chunk;
 		struct sk_buff *skb;
 
 		unix_state_lock(sk);
 		skb = skb_peek(&sk->sk_receive_queue);
+again:
 		if (skb == NULL) {
 			unix_sk(sk)->recursion_level = 0;
 			if (copied >= target)
@@ -1953,6 +1978,13 @@
 			unix_state_unlock(sk);
 			break;
 		}
+
+		if (skip >= skb->len) {
+			skip -= skb->len;
+			skb = skb_peek_next(skb, &sk->sk_receive_queue);
+			goto again;
+		}
+
 		unix_state_unlock(sk);
 
 		if (check_creds) {
@@ -1972,8 +2004,8 @@
 			sunaddr = NULL;
 		}
 
-		chunk = min_t(unsigned int, skb->len, size);
-		if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
+		chunk = min_t(unsigned int, skb->len - skip, size);
+		if (memcpy_toiovec(msg->msg_iov, skb->data + skip, chunk)) {
 			if (copied == 0)
 				copied = -EFAULT;
 			break;
@@ -1985,6 +2017,8 @@
 		if (!(flags & MSG_PEEK)) {
 			skb_pull(skb, chunk);
 
+			sk_peek_offset_bwd(sk, chunk);
+
 			if (UNIXCB(skb).fp)
 				unix_detach_fds(siocb->scm, skb);
 
@@ -2002,6 +2036,8 @@
 			if (UNIXCB(skb).fp)
 				siocb->scm->fp = scm_fp_dup(UNIXCB(skb).fp);
 
+			sk_peek_offset_fwd(sk, chunk);
+
 			break;
 		}
 	} while (size);