ipv6: use RCU in inet6_csk_xmit()

Use RCU to avoid changing dst_entry refcount in fast path.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 8a58e8cf6646b2bbe886bde46cdb72c7b548822a..2916200f90c1d21541e43012c5346929831b89c9 100644 (file)
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -211,6 +211,7 @@ int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
        struct flowi6 fl6;
        struct dst_entry *dst;
        struct in6_addr *final_p, final;
+       int res;
 
        memset(&fl6, 0, sizeof(fl6));
        fl6.flowi6_proto = sk->sk_protocol;
@@ -241,12 +242,14 @@ int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
                __inet6_csk_dst_store(sk, dst, NULL, NULL);
        }
 
-       skb_dst_set(skb, dst_clone(dst));
+       rcu_read_lock();
+       skb_dst_set_noref(skb, dst);
 
        /* Restore final destination back after routing done */
        ipv6_addr_copy(&fl6.daddr, &np->daddr);
 
-       return ip6_xmit(sk, skb, &fl6, np->opt);
+       res = ip6_xmit(sk, skb, &fl6, np->opt);
+       rcu_read_unlock();
+       return res;
 }
-
 EXPORT_SYMBOL_GPL(inet6_csk_xmit);