[PATCH v1 net-next 1/3] geneve: Unlink geneve->sock[46].hlist[46].hlist in __geneve_sock_release().

[Kuniyuki Iwashima <kuniyu@google.com>]

Currently, geneve->sock[46].hlist[46] is unliked from
geneve_sock.vni_list in geneve_stop() and geneve_sock.refcnt is
decremented for each socket later in __geneve_sock_release().

The following patch will introduce a mutex in geneve_net to
protect geneve_sock.{refcnt,vni_list}.

However, udp_tunnel_notify_del_rx_port() must be outside of the
lock to avoid AB-BA deadlock.

To make the change cleaner, let's move hlist_del_init_rcu()
from geneve_stop() to __geneve_sock_release().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 drivers/net/geneve.c | 42 +++++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 542e53f9dc3e..bd4fc6dba2fa 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1052,9 +1052,30 @@ static struct geneve_sock *geneve_socket_create(struct net *net,
 	return gs;
 }
 
-static void __geneve_sock_release(struct geneve_sock *gs)
+static void __geneve_sock_release(struct geneve_dev *geneve, bool ipv6)
 {
-	if (!gs || --gs->refcnt)
+	struct geneve_dev_node *node;
+	struct geneve_sock *gs;
+
+#if IS_ENABLED(CONFIG_IPV6)
+	if (ipv6) {
+		gs = rtnl_dereference(geneve->sock6);
+		rcu_assign_pointer(geneve->sock6, NULL);
+		node = &geneve->hlist6;
+	} else
+#endif
+	{
+		gs = rtnl_dereference(geneve->sock4);
+		rcu_assign_pointer(geneve->sock4, NULL);
+		node = &geneve->hlist4;
+	}
+
+	if (!gs)
+		return;
+
+	hlist_del_init_rcu(&node->hlist);
+
+	if (--gs->refcnt)
 		return;
 
 	list_del(&gs->list);
@@ -1065,19 +1086,10 @@ static void __geneve_sock_release(struct geneve_sock *gs)
 
 static void geneve_sock_release(struct geneve_dev *geneve)
 {
-	struct geneve_sock *gs4 = rtnl_dereference(geneve->sock4);
 #if IS_ENABLED(CONFIG_IPV6)
-	struct geneve_sock *gs6 = rtnl_dereference(geneve->sock6);
-
-	rcu_assign_pointer(geneve->sock6, NULL);
-#endif
-
-	rcu_assign_pointer(geneve->sock4, NULL);
-
-	__geneve_sock_release(gs4);
-#if IS_ENABLED(CONFIG_IPV6)
-	__geneve_sock_release(gs6);
+	__geneve_sock_release(geneve, true);
 #endif
+	__geneve_sock_release(geneve, false);
 }
 
 static struct geneve_sock *geneve_find_sock(struct net *net,
@@ -1187,10 +1199,6 @@ static int geneve_stop(struct net_device *dev)
 {
 	struct geneve_dev *geneve = netdev_priv(dev);
 
-	hlist_del_init_rcu(&geneve->hlist4.hlist);
-#if IS_ENABLED(CONFIG_IPV6)
-	hlist_del_init_rcu(&geneve->hlist6.hlist);
-#endif
 	geneve_sock_release(geneve);
 	return 0;
 }
-- 
2.55.0.571.g244d577d93-goog