ipv4: prepare net initialization for IP accounting

Some places, that deal with IP statistics already have where to
get a struct net from, but use it directly, without declaring
a separate variable on the stack.

So, save this net on the stack for future IP_XXX_STATS macros.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index fdd4faa..048ef57 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -656,8 +656,10 @@
 				    .uli_u = { .ports =
 					       { .sport = inet->sport,
 						 .dport = dport } } };
+		struct net *net = sock_net(sk);
+
 		security_sk_classify_flow(sk, &fl);
-		err = ip_route_output_flow(sock_net(sk), &rt, &fl, sk, 1);
+		err = ip_route_output_flow(net, &rt, &fl, sk, 1);
 		if (err) {
 			if (err == -ENETUNREACH)
 				IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);