1 files changed, 17 insertions, 12 deletions

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 75703fda23e7..319aa8ed9cf8 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -362,7 +362,7 @@ try_again:
 	if (!skb)
 		return err;
 
-	ulen = skb->len;
+	ulen = udp_skb_len(skb);
 	copied = len;
 	if (copied > ulen - off)
 		copied = ulen - off;
@@ -379,14 +379,18 @@ try_again:
 
 	if (copied < ulen || peeking ||
 	    (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
-		checksum_valid = !udp_lib_checksum_complete(skb);
+		checksum_valid = udp_skb_csum_unnecessary(skb) ||
+				!__udp_lib_checksum_complete(skb);
 		if (!checksum_valid)
 			goto csum_copy_err;
 	}
 
-	if (checksum_valid || skb_csum_unnecessary(skb))
-		err = skb_copy_datagram_msg(skb, off, msg, copied);
-	else {
+	if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
+		if (udp_skb_is_linear(skb))
+			err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
+		else
+			err = skb_copy_datagram_msg(skb, off, msg, copied);
+	} else {
 		err = skb_copy_and_csum_datagram_msg(skb, off, msg);
 		if (err == -EINVAL)
 			goto csum_copy_err;
@@ -455,7 +459,8 @@ try_again:
 	return err;
 
 csum_copy_err:
-	if (!__sk_queue_drop_skb(sk, skb, flags, udp_skb_destructor)) {
+	if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
+				 udp_skb_destructor)) {
 		if (is_udp4) {
 			UDP_INC_STATS(sock_net(sk),
 				      UDP_MIB_CSUMERRORS, is_udplite);
@@ -629,6 +634,7 @@ static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		}
 	}
 
+	prefetch(&sk->sk_rmem_alloc);
 	if (rcu_access_pointer(sk->sk_filter) &&
 	    udp_lib_checksum_complete(skb))
 		goto csum_error;
@@ -920,12 +926,11 @@ static void udp_v6_early_demux(struct sk_buff *skb)
 	if (dst)
 		dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
 	if (dst) {
-		if (dst->flags & DST_NOCACHE) {
-			if (likely(atomic_inc_not_zero(&dst->__refcnt)))
-				skb_dst_set(skb, dst);
-		} else {
-			skb_dst_set_noref(skb, dst);
-		}
+		/* set noref for now.
+		 * any place which wants to hold dst has to call
+		 * dst_hold_safe()
+		 */
+		skb_dst_set_noref(skb, dst);
 	}
 }