[PATCH v1 net-next 13/15] pfcp: Store struct sock in struct pfcp_dev.

[Kuniyuki Iwashima <kuniyu@google.com>]

pfcp does not need to access struct socket itself in the fast
path; it only reads struct sock, and struct socket is only used
for tunnel setup and teardown.

Let's store struct sock directly in struct pfcp_dev.

pfcp_del_sock() is called from dev->netdev_ops->ndo_uninit().
The 2nd synchronize_net() in unregister_netdevice_many_notify()
ensures that inflight pfcp RX fast paths finish before pfcp_dev
is freed.

Note that synchronize_rcu() is added in the error path of
pfcp_newlink() since free_netdev() will free pfcp_dev immediately
once we remove synchronize_rcu() in udp_tunnel_sock_release().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 drivers/net/pfcp.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/pfcp.c b/drivers/net/pfcp.c
index 870137695e8a..5f1c9d2c0b49 100644
--- a/drivers/net/pfcp.c
+++ b/drivers/net/pfcp.c
@@ -18,7 +18,7 @@
 struct pfcp_dev {
 	struct list_head	list;
 
-	struct socket		*sock;
+	struct sock		*sk;
 	struct net_device	*dev;
 	struct net		*net;
 
@@ -104,8 +104,8 @@ static int pfcp_encap_recv(struct sock *sk, struct sk_buff *skb)
 
 static void pfcp_del_sock(struct pfcp_dev *pfcp)
 {
-	udp_tunnel_sock_release(pfcp->sock->sk);
-	pfcp->sock = NULL;
+	udp_tunnel_sock_release(pfcp->sk);
+	pfcp->sk = NULL;
 }
 
 static void pfcp_dev_uninit(struct net_device *dev)
@@ -151,7 +151,7 @@ static void pfcp_link_setup(struct net_device *dev)
 	netif_keep_dst(dev);
 }
 
-static struct socket *pfcp_create_sock(struct pfcp_dev *pfcp)
+static struct sock *pfcp_create_sock(struct pfcp_dev *pfcp)
 {
 	struct udp_tunnel_sock_cfg tuncfg = {};
 	struct udp_port_cfg udp_conf = {
@@ -174,14 +174,14 @@ static struct socket *pfcp_create_sock(struct pfcp_dev *pfcp)
 
 	setup_udp_tunnel_sock(net, sock->sk, &tuncfg);
 
-	return sock;
+	return sock->sk;
 }
 
 static int pfcp_add_sock(struct pfcp_dev *pfcp)
 {
-	pfcp->sock = pfcp_create_sock(pfcp);
+	pfcp->sk = pfcp_create_sock(pfcp);
 
-	return PTR_ERR_OR_ZERO(pfcp->sock);
+	return PTR_ERR_OR_ZERO(pfcp->sk);
 }
 
 static int pfcp_newlink(struct net_device *dev,
@@ -216,6 +216,7 @@ static int pfcp_newlink(struct net_device *dev,
 
 exit_del_pfcp_sock:
 	pfcp_del_sock(pfcp);
+	synchronize_rcu();
 exit_err:
 	pfcp->net = NULL;
 	return err;
-- 
2.54.0.545.g6539524ca2-goog