net: Pre-COW metrics for TCP.

TCP is going to record metrics for the connection,
so pre-COW the route metrics at route cache entry
creation time.

This avoids several atomic operations that have to
occur if we COW the metrics after the entry reaches
global visibility.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 1 deletions

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 8181498fa96c..6e6dfd757682 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -219,7 +219,13 @@ static inline struct request_sock *inet_reqsk_alloc(struct request_sock_ops *ops
 
 static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
 {
-        return inet_sk(sk)->transparent ? FLOWI_FLAG_ANYSRC : 0;
+        __u8 flags = 0;
+
+        if (inet_sk(sk)->transparent)
+                flags |= FLOWI_FLAG_ANYSRC;
+        if (sk->sk_protocol == IPPROTO_TCP)
+                flags |= FLOWI_FLAG_PRECOW_METRICS;
+        return flags;
 }
 
 #endif  /* _INET_SOCK_H */