[ovs-dev] [PATCH v2 3/3] datapath: vxlan: Optimize vxlan rcv

[Pravin B Shelar]

vxlan-udp-recv function lookup vxlan_sock struct on every packet
recv by using udp-port number. we can use sk->sk_user_data to
store vxlan_sock and avoid lookup.
I have open coded rcu-api to store and read vxlan_sock from
sk_user_data to avoid sparse warning as sk_user_data is not
__rcu pointer.

backport of upstream commit 430eda6d6d56 (vxlan: Optimize
vxlan rcv).

Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
---
v2:
Use ACCESS_ONCE() to read vs.
---
 datapath/linux/compat/vxlan.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/datapath/linux/compat/vxlan.c b/datapath/linux/compat/vxlan.c
index db14f2f..0b6fd36 100644
--- a/datapath/linux/compat/vxlan.c
+++ b/datapath/linux/compat/vxlan.c
@@ -124,7 +124,8 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 	if (iptunnel_pull_header(skb, VXLAN_HLEN, htons(ETH_P_TEB)))
 		goto drop;
 
-	vs = vxlan_find_sock(sock_net(sk), inet_sport(sk));
+	vs = (struct vxlan_sock *)ACCESS_ONCE(sk->sk_user_data);
+	smp_read_barrier_depends();
 	if (!vs)
 		goto drop;
 
@@ -322,6 +323,8 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, __be16 port,
 	}
 	vs->rcv = rcv;
 	vs->data = data;
+	smp_wmb();
+	vs->sock->sk->sk_user_data = vs;
 
 	/* Disable multicast loopback */
 	inet_sk(sk)->mc_loop = 0;
@@ -359,6 +362,8 @@ void vxlan_sock_release(struct vxlan_sock *vs)
 
 	spin_lock(&vn->sock_lock);
 	hlist_del_rcu(&vs->hlist);
+	smp_wmb();
+	vs->sock->sk->sk_user_data = NULL;
 	spin_unlock(&vn->sock_lock);
 
 	queue_work(&vs->del_work);
-- 
1.7.1