Merge branch 'udp_tunnel-remove-rtnl_lock-dependency'

Stanislav Fomichev says:

====================
udp_tunnel: remove rtnl_lock dependency

Recently bnxt had to grow back a bunch of rtnl dependencies because
of udp_tunnel's infra. Add separate (global) mutext to protect
udp_tunnel state.
====================

Link: https://patch.msgid.link/20250616162117.287806-1-stfomichev@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 63 insertions, 24 deletions

diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index e3c70b579095..cbd3a43074bd 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -130,22 +130,6 @@ void udp_tunnel_drop_rx_port(struct net_device *dev, struct socket *sock,
 void udp_tunnel_notify_add_rx_port(struct socket *sock, unsigned short type);
 void udp_tunnel_notify_del_rx_port(struct socket *sock, unsigned short type);
 
-static inline void udp_tunnel_get_rx_info(struct net_device *dev)
-{
-	ASSERT_RTNL();
-	if (!(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
-		return;
-	call_netdevice_notifiers(NETDEV_UDP_TUNNEL_PUSH_INFO, dev);
-}
-
-static inline void udp_tunnel_drop_rx_info(struct net_device *dev)
-{
-	ASSERT_RTNL();
-	if (!(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
-		return;
-	call_netdevice_notifiers(NETDEV_UDP_TUNNEL_DROP_INFO, dev);
-}
-
 /* Transmit the skb using UDP encapsulation. */
 void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
 			 __be32 src, __be32 dst, __u8 tos, __u8 ttl,
@@ -222,19 +206,17 @@ static inline void udp_tunnel_encap_enable(struct sock *sk)
 #define UDP_TUNNEL_NIC_MAX_TABLES	4
 
 enum udp_tunnel_nic_info_flags {
-	/* Device callbacks may sleep */
-	UDP_TUNNEL_NIC_INFO_MAY_SLEEP	= BIT(0),
 	/* Device only supports offloads when it's open, all ports
 	 * will be removed before close and re-added after open.
 	 */
-	UDP_TUNNEL_NIC_INFO_OPEN_ONLY	= BIT(1),
+	UDP_TUNNEL_NIC_INFO_OPEN_ONLY	= BIT(0),
 	/* Device supports only IPv4 tunnels */
-	UDP_TUNNEL_NIC_INFO_IPV4_ONLY	= BIT(2),
+	UDP_TUNNEL_NIC_INFO_IPV4_ONLY	= BIT(1),
 	/* Device has hard-coded the IANA VXLAN port (4789) as VXLAN.
 	 * This port must not be counted towards n_entries of any table.
 	 * Driver will not receive any callback associated with port 4789.
 	 */
-	UDP_TUNNEL_NIC_INFO_STATIC_IANA_VXLAN	= BIT(3),
+	UDP_TUNNEL_NIC_INFO_STATIC_IANA_VXLAN	= BIT(2),
 };
 
 struct udp_tunnel_nic;
@@ -325,6 +307,9 @@ struct udp_tunnel_nic_ops {
 	size_t (*dump_size)(struct net_device *dev, unsigned int table);
 	int (*dump_write)(struct net_device *dev, unsigned int table,
 			  struct sk_buff *skb);
+	void (*assert_locked)(struct net_device *dev);
+	void (*lock)(struct net_device *dev);
+	void (*unlock)(struct net_device *dev);
 };
 
 #ifdef CONFIG_INET
@@ -353,8 +338,29 @@ static inline void
 udp_tunnel_nic_set_port_priv(struct net_device *dev, unsigned int table,
 			     unsigned int idx, u8 priv)
 {
-	if (udp_tunnel_nic_ops)
+	if (udp_tunnel_nic_ops) {
+		udp_tunnel_nic_ops->lock(dev);
 		udp_tunnel_nic_ops->set_port_priv(dev, table, idx, priv);
+		udp_tunnel_nic_ops->unlock(dev);
+	}
+}
+
+static inline void udp_tunnel_nic_assert_locked(struct net_device *dev)
+{
+	if (udp_tunnel_nic_ops)
+		udp_tunnel_nic_ops->assert_locked(dev);
+}
+
+static inline void udp_tunnel_nic_lock(struct net_device *dev)
+{
+	if (udp_tunnel_nic_ops)
+		udp_tunnel_nic_ops->lock(dev);
+}
+
+static inline void udp_tunnel_nic_unlock(struct net_device *dev)
+{
+	if (udp_tunnel_nic_ops)
+		udp_tunnel_nic_ops->unlock(dev);
 }
 
 static inline void
@@ -396,17 +402,50 @@ static inline void udp_tunnel_nic_reset_ntf(struct net_device *dev)
 static inline size_t
 udp_tunnel_nic_dump_size(struct net_device *dev, unsigned int table)
 {
+	size_t ret;
+
 	if (!udp_tunnel_nic_ops)
 		return 0;
-	return udp_tunnel_nic_ops->dump_size(dev, table);
+
+	udp_tunnel_nic_ops->lock(dev);
+	ret = udp_tunnel_nic_ops->dump_size(dev, table);
+	udp_tunnel_nic_ops->unlock(dev);
+
+	return ret;
 }
 
 static inline int
 udp_tunnel_nic_dump_write(struct net_device *dev, unsigned int table,
 			  struct sk_buff *skb)
 {
+	int ret;
+
 	if (!udp_tunnel_nic_ops)
 		return 0;
-	return udp_tunnel_nic_ops->dump_write(dev, table, skb);
+
+	udp_tunnel_nic_ops->lock(dev);
+	ret = udp_tunnel_nic_ops->dump_write(dev, table, skb);
+	udp_tunnel_nic_ops->unlock(dev);
+
+	return ret;
+}
+
+static inline void udp_tunnel_get_rx_info(struct net_device *dev)
+{
+	ASSERT_RTNL();
+	if (!(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
+		return;
+	udp_tunnel_nic_assert_locked(dev);
+	call_netdevice_notifiers(NETDEV_UDP_TUNNEL_PUSH_INFO, dev);
 }
+
+static inline void udp_tunnel_drop_rx_info(struct net_device *dev)
+{
+	ASSERT_RTNL();
+	if (!(dev->features & NETIF_F_RX_UDP_TUNNEL_PORT))
+		return;
+	udp_tunnel_nic_assert_locked(dev);
+	call_netdevice_notifiers(NETDEV_UDP_TUNNEL_DROP_INFO, dev);
+}
+
 #endif