diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-05-10 15:31:49 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-05-18 04:18:52 +0400 |
| commit | ab6e3feba1f1bc3b9418b854da6f481408d243de (patch) | |
| tree | 18977292fa858067f7cc4d7a7df8a69dd5562a3d | |
| parent | 4a94445c9a5cf5461fb41d80040033b9a8e2a85a (diff) | |
| download | linux-ab6e3feba1f1bc3b9418b854da6f481408d243de.tar.xz | |
net: No dst refcounting in ip_queue_xmit()
TCP outgoing packets can avoid two atomic ops, and dirtying
of previously higly contended cache line using new refdst
infrastructure.
Note 1: loopback device excluded because of !IFF_XMIT_DST_RELEASE
Note 2: UDP packets dsts are built before ip_queue_xmit().
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/ip_output.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 252897443ef9..9a4a6c96cb0d 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -318,10 +318,12 @@ int ip_queue_xmit(struct sk_buff *skb) struct ip_options *opt = inet->opt; struct rtable *rt; struct iphdr *iph; + int res; /* Skip all of this if the packet is already routed, * f.e. by something like SCTP. */ + rcu_read_lock(); rt = skb_rtable(skb); if (rt != NULL) goto packet_routed; @@ -359,7 +361,7 @@ int ip_queue_xmit(struct sk_buff *skb) } sk_setup_caps(sk, &rt->u.dst); } - skb_dst_set(skb, dst_clone(&rt->u.dst)); + skb_dst_set_noref(skb, &rt->u.dst); packet_routed: if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) @@ -391,9 +393,12 @@ packet_routed: skb->priority = sk->sk_priority; skb->mark = sk->sk_mark; - return ip_local_out(skb); + res = ip_local_out(skb); + rcu_read_unlock(); + return res; no_route: + rcu_read_unlock(); IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); kfree_skb(skb); return -EHOSTUNREACH; |