[SOCK]: Introduce sk_setup_caps

From tcp_v4_setup_caps, that always is preceded by a call to
__sk_dst_set, so coalesce this sequence into sk_setup_caps, removing
one call to a TCP function in the IP layer.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sock.h b/include/net/sock.h
index f91ee82..69d869e 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1025,6 +1025,16 @@
 	return dst;
 }
 
+static inline void sk_setup_caps(struct sock *sk, struct dst_entry *dst)
+{
+	__sk_dst_set(sk, dst);
+	sk->sk_route_caps = dst->dev->features;
+	if (sk->sk_route_caps & NETIF_F_TSO) {
+		if (sock_flag(sk, SOCK_NO_LARGESEND) || dst->header_len)
+			sk->sk_route_caps &= ~NETIF_F_TSO;
+	}
+}
+
 static inline void sk_charge_skb(struct sock *sk, struct sk_buff *skb)
 {
 	sk->sk_wmem_queued   += skb->truesize;