vxlan: Store struct sock in struct vxlan_sock.

Commit 3cf7203ca620 ("net/tunnel: wait until all sk_user_data
reader finish before releasing the sock") added synchronize_rcu()
in udp_tunnel_sock_release().

This was intended to protect the fast path of a dying vxlan device
from dereferencing vxlan_sock->sock->sk after sock_orphan() has set
sock->sk to NULL.

However, vxlan 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 vxlan_sock.

In the next patch, we will free vxlan_sock with kfree_rcu(), then
vxlan no longer needs synchronize_rcu() in udp_tunnel_sock_release().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260502031401.3557229-8-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index abf3ae04d75b97f81f7c4501e41a5e13bb7e389f..ce99da44ea7d834f784489eae78ba59afa86812d 100644 (file)
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -88,10 +88,10 @@ static struct vxlan_sock *vxlan_find_sock(struct net *net, sa_family_t family,
        flags &= VXLAN_F_RCV_FLAGS;
 
        hlist_for_each_entry_rcu(vs, vs_head(net, port), hlist) {
-               if (inet_sk(vs->sock->sk)->inet_sport == port &&
+               if (inet_sk(vs->sk)->inet_sport == port &&
                    vxlan_get_sk_family(vs) == family &&
                    vs->flags == flags &&
-                   vs->sock->sk->sk_bound_dev_if == ifindex)
+                   vs->sk->sk_bound_dev_if == ifindex)
                        return vs;
        }
        return NULL;
@@ -1497,7 +1497,7 @@ static bool __vxlan_sock_release_prep(struct vxlan_sock *vs)
                return false;
 
        hlist_del_rcu(&vs->hlist);
-       udp_tunnel_notify_del_rx_port(vs->sock->sk,
+       udp_tunnel_notify_del_rx_port(vs->sk,
                                      (vs->flags & VXLAN_F_GPE) ?
                                      UDP_TUNNEL_TYPE_VXLAN_GPE :
                                      UDP_TUNNEL_TYPE_VXLAN);
@@ -1523,13 +1523,13 @@ static void vxlan_sock_release(struct vxlan_dev *vxlan)
                vxlan_vs_del_dev(vxlan);
 
        if (__vxlan_sock_release_prep(sock4)) {
-               udp_tunnel_sock_release(sock4->sock->sk);
+               udp_tunnel_sock_release(sock4->sk);
                kfree(sock4);
        }
 
 #if IS_ENABLED(CONFIG_IPV6)
        if (__vxlan_sock_release_prep(sock6)) {
-               udp_tunnel_sock_release(sock6->sock->sk);
+               udp_tunnel_sock_release(sock6->sk);
                kfree(sock6);
        }
 #endif
@@ -2477,7 +2477,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                }
 
                if (!ifindex)
-                       ifindex = sock4->sock->sk->sk_bound_dev_if;
+                       ifindex = sock4->sk->sk_bound_dev_if;
 
                rt = udp_tunnel_dst_lookup(skb, dev, vxlan->net, ifindex,
                                           &saddr, pkey, src_port, dst_port,
@@ -2544,7 +2544,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                        goto tx_error;
                }
 
-               udp_tunnel_xmit_skb(rt, sock4->sock->sk, skb, saddr,
+               udp_tunnel_xmit_skb(rt, sock4->sk, skb, saddr,
                                    pkey->u.ipv4.dst, tos, ttl, df,
                                    src_port, dst_port, xnet, !udp_sum,
                                    ipcb_flags);
@@ -2561,9 +2561,9 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                }
 
                if (!ifindex)
-                       ifindex = sock6->sock->sk->sk_bound_dev_if;
+                       ifindex = sock6->sk->sk_bound_dev_if;
 
-               ndst = udp_tunnel6_dst_lookup(skb, dev, vxlan->net, sock6->sock->sk,
+               ndst = udp_tunnel6_dst_lookup(skb, dev, vxlan->net, sock6->sk,
                                              ifindex, &saddr, pkey,
                                              src_port, dst_port, tos,
                                              use_cache ? dst_cache : NULL);
@@ -2619,7 +2619,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                        goto tx_error;
                }
 
-               udp_tunnel6_xmit_skb(ndst, sock6->sock->sk, skb, dev,
+               udp_tunnel6_xmit_skb(ndst, sock6->sk, skb, dev,
                                     &saddr, &pkey->u.ipv6.dst, tos, ttl,
                                     pkey->label, src_port, dst_port, !udp_sum,
                                     ip6cb_flags);
@@ -3258,7 +3258,7 @@ static int vxlan_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
                if (!sock6)
                        return -EIO;
 
-               ndst = udp_tunnel6_dst_lookup(skb, dev, vxlan->net, sock6->sock->sk,
+               ndst = udp_tunnel6_dst_lookup(skb, dev, vxlan->net, sock6->sk,
                                              0, &info->key.u.ipv6.src,
                                              &info->key,
                                              sport, dport, info->key.tos,
@@ -3336,9 +3336,9 @@ static void vxlan_offload_rx_ports(struct net_device *dev, bool push)
                                type = UDP_TUNNEL_TYPE_VXLAN;
 
                        if (push)
-                               udp_tunnel_push_rx_port(dev, vs->sock->sk, type);
+                               udp_tunnel_push_rx_port(dev, vs->sk, type);
                        else
-                               udp_tunnel_drop_rx_port(dev, vs->sock->sk, type);
+                               udp_tunnel_drop_rx_port(dev, vs->sk, type);
                }
        }
 }
@@ -3544,8 +3544,8 @@ static const struct ethtool_ops vxlan_ethtool_ops = {
        .get_link_ksettings     = vxlan_get_link_ksettings,
 };
 
-static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
-                                       __be16 port, u32 flags, int ifindex)
+static struct sock *vxlan_create_sock(struct net *net, bool ipv6,
+                                     __be16 port, u32 flags, int ifindex)
 {
        struct socket *sock;
        struct udp_port_cfg udp_conf;
@@ -3571,7 +3571,7 @@ static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
                return ERR_PTR(err);
 
        udp_allow_gso(sock->sk);
-       return sock;
+       return sock->sk;
 }
 
 /* Create new listen socket if needed */
@@ -3579,10 +3579,10 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
                                              __be16 port, u32 flags,
                                              int ifindex)
 {
+       struct udp_tunnel_sock_cfg tunnel_cfg;
        struct vxlan_sock *vs;
-       struct socket *sock;
+       struct sock *sk;
        unsigned int h;
-       struct udp_tunnel_sock_cfg tunnel_cfg;
 
        ASSERT_RTNL();
 
@@ -3593,18 +3593,18 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
        for (h = 0; h < VNI_HASH_SIZE; ++h)
                INIT_HLIST_HEAD(&vs->vni_list[h]);
 
-       sock = vxlan_create_sock(net, ipv6, port, flags, ifindex);
-       if (IS_ERR(sock)) {
+       sk = vxlan_create_sock(net, ipv6, port, flags, ifindex);
+       if (IS_ERR(sk)) {
                kfree(vs);
-               return ERR_CAST(sock);
+               return ERR_CAST(sk);
        }
 
-       vs->sock = sock;
+       vs->sk = sk;
        refcount_set(&vs->refcnt, 1);
        vs->flags = (flags & VXLAN_F_RCV_FLAGS);
 
        hlist_add_head_rcu(&vs->hlist, vs_head(net, port));
-       udp_tunnel_notify_add_rx_port(sock->sk,
+       udp_tunnel_notify_add_rx_port(sk,
                                      (vs->flags & VXLAN_F_GPE) ?
                                      UDP_TUNNEL_TYPE_VXLAN_GPE :
                                      UDP_TUNNEL_TYPE_VXLAN);
@@ -3624,7 +3624,7 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
                tunnel_cfg.gro_complete = vxlan_gro_complete;
        }
 
-       setup_udp_tunnel_sock(net, sock->sk, &tunnel_cfg);
+       setup_udp_tunnel_sock(net, sk, &tunnel_cfg);
 
        return vs;
 }

diff --git a/drivers/net/vxlan/vxlan_multicast.c b/drivers/net/vxlan/vxlan_multicast.c
index b0e80bca855cc03ada9be9a0a391595a932f109e..3b75b48dc726df40cebb233095a8a046ee274c30 100644 (file)
--- a/drivers/net/vxlan/vxlan_multicast.c
+++ b/drivers/net/vxlan/vxlan_multicast.c
@@ -29,7 +29,7 @@ int vxlan_igmp_join(struct vxlan_dev *vxlan, union vxlan_addr *rip,
                        .imr_ifindex            = ifindex,
                };
 
-               sk = sock4->sock->sk;
+               sk = sock4->sk;
                lock_sock(sk);
                ret = ip_mc_join_group(sk, &mreq);
                release_sock(sk);
@@ -37,7 +37,7 @@ int vxlan_igmp_join(struct vxlan_dev *vxlan, union vxlan_addr *rip,
        } else {
                struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);
 
-               sk = sock6->sock->sk;
+               sk = sock6->sk;
                lock_sock(sk);
                ret = ipv6_sock_mc_join(sk, ifindex, &ip->sin6.sin6_addr);
                release_sock(sk);
@@ -62,7 +62,7 @@ int vxlan_igmp_leave(struct vxlan_dev *vxlan, union vxlan_addr *rip,
                        .imr_ifindex            = ifindex,
                };
 
-               sk = sock4->sock->sk;
+               sk = sock4->sk;
                lock_sock(sk);
                ret = ip_mc_leave_group(sk, &mreq);
                release_sock(sk);
@@ -70,7 +70,7 @@ int vxlan_igmp_leave(struct vxlan_dev *vxlan, union vxlan_addr *rip,
        } else {
                struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);
 
-               sk = sock6->sock->sk;
+               sk = sock6->sk;
                lock_sock(sk);
                ret = ipv6_sock_mc_drop(sk, ifindex, &ip->sin6.sin6_addr);
                release_sock(sk);

diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 0ee50785f4f1c26894f05b5e1ae52aad781bd062..8b52294b2902714bbbf833c96eca99f09ef26a4d 100644 (file)
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -185,7 +185,7 @@ struct vxlan_metadata {
 /* per UDP socket information */
 struct vxlan_sock {
        struct hlist_node hlist;
-       struct socket    *sock;
+       struct sock       *sk;
        struct hlist_head vni_list[VNI_HASH_SIZE];
        refcount_t        refcnt;
        u32               flags;
@@ -448,7 +448,7 @@ static inline __be32 vxlan_compute_rco(unsigned int start, unsigned int offset)
 
 static inline unsigned short vxlan_get_sk_family(struct vxlan_sock *vs)
 {
-       return vs->sock->sk->sk_family;
+       return vs->sk->sk_family;
 }
 
 #if IS_ENABLED(CONFIG_IPV6)