--- net/ipv4/ip_output.c

+++ net/ipv4/ip_output.c

@@ -867,8 +867,10 @@ int ip_append_data(struct sock *sk,

!exthdrlen)

csummode = CHECKSUM_PARTIAL;

+ skb = skb_peek_tail(&sk->sk_write_queue);

+

inet->cork.length += length;

- if (((length> mtu) || !skb_queue_empty(&sk->sk_write_queue)) &&

+ if (((length > mtu) || (skb && skb_is_gso(skb))) &&

(sk->sk_protocol == IPPROTO_UDP) &&

(rt->u.dst.dev->features & NETIF_F_UFO)) {

err = ip_ufo_append_data(sk, getfrag, from, length, hh_len,

@@ -886,7 +888,7 @@ int ip_append_data(struct sock *sk,

* adding appropriate IP header.

*/

- if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL)

+ if (!skb)

goto alloc_new_skb;

while (length > 0) {

@@ -1115,7 +1117,8 @@ ssize_t ip_append_page(struct sock *sk,

return -EINVAL;

inet->cork.length += size;

- if ((sk->sk_protocol == IPPROTO_UDP) &&

+ if ((size + skb->len > mtu) &&

+ (sk->sk_protocol == IPPROTO_UDP) &&

(rt->u.dst.dev->features & NETIF_F_UFO)) {

skb_shinfo(skb)->gso_size = mtu - fragheaderlen;

skb_shinfo(skb)->gso_type = SKB_GSO_UDP;