inet: Don't lookup the socket if there's a socket attached to the skb

Use the socket cached in the skb if it's present.

Signed-off-by: KOVACS Krisztian <hidden@sch.bme.hu>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 3 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index c7a90b546b21..822c9deac83b 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -306,11 +306,15 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
                                                  __be16 sport, __be16 dport,
                                                  struct hlist_head udptable[])
 {
+        struct sock *sk;
         const struct iphdr *iph = ip_hdr(skb);
 
-        return __udp4_lib_lookup(dev_net(skb->dst->dev), iph->saddr, sport,
-                                 iph->daddr, dport, inet_iif(skb),
-                                 udptable);
+        if (unlikely(sk = skb_steal_sock(skb)))
+                return sk;
+        else
+                return __udp4_lib_lookup(dev_net(skb->dst->dev), iph->saddr, sport,
+                                         iph->daddr, dport, inet_iif(skb),
+                                         udptable);
 }
 
 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,