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vxlan: move IGMP join/leave to work queue
Do join/leave from work queue to avoid lock inversion problems between normal socket and RTNL. The code comes out cleaner as well. Uses Cong Wang's suggestion to turn refcnt into a real atomic since now need to handle case where last use of socket is IGMP worker. Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
This commit is contained in:
Stephen Hemminger
parent
758c57d16a
commit
7c47cedf43
@ -85,7 +85,7 @@ struct vxlan_sock {
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struct hlist_node hlist;
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struct rcu_head rcu;
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struct work_struct del_work;
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unsigned int refcnt;
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atomic_t refcnt;
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struct socket *sock;
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struct hlist_head vni_list[VNI_HASH_SIZE];
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};
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@ -131,6 +131,7 @@ struct vxlan_dev {
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__u8 ttl;
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u32 flags; /* VXLAN_F_* below */
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struct work_struct igmp_work;
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unsigned long age_interval;
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struct timer_list age_timer;
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spinlock_t hash_lock;
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@ -648,76 +649,58 @@ static bool vxlan_snoop(struct net_device *dev,
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/* See if multicast group is already in use by other ID */
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static bool vxlan_group_used(struct vxlan_net *vn,
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const struct vxlan_dev *this)
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static bool vxlan_group_used(struct vxlan_net *vn, __be32 remote_ip)
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{
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struct vxlan_dev *vxlan;
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list_for_each_entry(vxlan, &vn->vxlan_list, next) {
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if (vxlan == this)
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continue;
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if (!netif_running(vxlan->dev))
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continue;
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if (vxlan->default_dst.remote_ip == this->default_dst.remote_ip)
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if (vxlan->default_dst.remote_ip == remote_ip)
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return true;
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}
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return false;
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}
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/* kernel equivalent to IP_ADD_MEMBERSHIP */
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static int vxlan_join_group(struct net_device *dev)
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static void vxlan_sock_hold(struct vxlan_sock *vs)
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{
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struct vxlan_dev *vxlan = netdev_priv(dev);
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struct vxlan_net *vn = net_generic(dev_net(dev), vxlan_net_id);
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struct sock *sk = vxlan->vn_sock->sock->sk;
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struct ip_mreqn mreq = {
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.imr_multiaddr.s_addr = vxlan->default_dst.remote_ip,
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.imr_ifindex = vxlan->default_dst.remote_ifindex,
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};
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int err;
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/* Already a member of group */
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if (vxlan_group_used(vn, vxlan))
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return 0;
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/* Need to drop RTNL to call multicast join */
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rtnl_unlock();
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lock_sock(sk);
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err = ip_mc_join_group(sk, &mreq);
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release_sock(sk);
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rtnl_lock();
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return err;
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atomic_inc(&vs->refcnt);
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}
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/* kernel equivalent to IP_DROP_MEMBERSHIP */
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static int vxlan_leave_group(struct net_device *dev)
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static void vxlan_sock_release(struct vxlan_sock *vs)
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{
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struct vxlan_dev *vxlan = netdev_priv(dev);
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struct vxlan_net *vn = net_generic(dev_net(dev), vxlan_net_id);
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int err = 0;
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struct sock *sk = vxlan->vn_sock->sock->sk;
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if (!atomic_dec_and_test(&vs->refcnt))
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return;
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hlist_del_rcu(&vs->hlist);
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queue_work(vxlan_wq, &vs->del_work);
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}
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/* Callback to update multicast group membership.
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* Scheduled when vxlan goes up/down.
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*/
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static void vxlan_igmp_work(struct work_struct *work)
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{
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struct vxlan_dev *vxlan = container_of(work, struct vxlan_dev, igmp_work);
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struct vxlan_net *vn = net_generic(dev_net(vxlan->dev), vxlan_net_id);
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struct vxlan_sock *vs = vxlan->vn_sock;
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struct sock *sk = vs->sock->sk;
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struct ip_mreqn mreq = {
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.imr_multiaddr.s_addr = vxlan->default_dst.remote_ip,
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.imr_ifindex = vxlan->default_dst.remote_ifindex,
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};
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/* Only leave group when last vxlan is done. */
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if (vxlan_group_used(vn, vxlan))
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return 0;
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/* Need to drop RTNL to call multicast leave */
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rtnl_unlock();
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lock_sock(sk);
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err = ip_mc_leave_group(sk, &mreq);
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if (vxlan_group_used(vn, vxlan->default_dst.remote_ip))
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ip_mc_join_group(sk, &mreq);
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else
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ip_mc_leave_group(sk, &mreq);
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release_sock(sk);
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rtnl_lock();
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return err;
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vxlan_sock_release(vs);
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dev_put(vxlan->dev);
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}
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/* Callback from net/ipv4/udp.c to receive packets */
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@ -1249,12 +1232,11 @@ static int vxlan_init(struct net_device *dev)
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static int vxlan_open(struct net_device *dev)
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{
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struct vxlan_dev *vxlan = netdev_priv(dev);
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int err;
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if (IN_MULTICAST(ntohl(vxlan->default_dst.remote_ip))) {
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err = vxlan_join_group(dev);
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if (err)
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return err;
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vxlan_sock_hold(vxlan->vn_sock);
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dev_hold(dev);
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queue_work(vxlan_wq, &vxlan->igmp_work);
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}
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if (vxlan->age_interval)
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@ -1285,8 +1267,11 @@ static int vxlan_stop(struct net_device *dev)
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{
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struct vxlan_dev *vxlan = netdev_priv(dev);
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if (IN_MULTICAST(ntohl(vxlan->default_dst.remote_ip)))
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vxlan_leave_group(dev);
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if (IN_MULTICAST(ntohl(vxlan->default_dst.remote_ip))) {
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vxlan_sock_hold(vxlan->vn_sock);
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dev_hold(dev);
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queue_work(vxlan_wq, &vxlan->igmp_work);
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}
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del_timer_sync(&vxlan->age_timer);
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@ -1355,6 +1340,7 @@ static void vxlan_setup(struct net_device *dev)
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INIT_LIST_HEAD(&vxlan->next);
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spin_lock_init(&vxlan->hash_lock);
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INIT_WORK(&vxlan->igmp_work, vxlan_igmp_work);
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init_timer_deferrable(&vxlan->age_timer);
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vxlan->age_timer.function = vxlan_cleanup;
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@ -1498,8 +1484,8 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, __be16 port)
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udp_sk(sk)->encap_type = 1;
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udp_sk(sk)->encap_rcv = vxlan_udp_encap_recv;
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udp_encap_enable();
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atomic_set(&vs->refcnt, 1);
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vs->refcnt = 1;
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return vs;
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}
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@ -1589,7 +1575,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
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vs = vxlan_find_port(net, vxlan->dst_port);
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if (vs)
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++vs->refcnt;
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atomic_inc(&vs->refcnt);
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else {
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/* Drop lock because socket create acquires RTNL lock */
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rtnl_unlock();
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@ -1606,12 +1592,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
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err = register_netdevice(dev);
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if (err) {
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if (--vs->refcnt == 0) {
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rtnl_unlock();
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sk_release_kernel(vs->sock->sk);
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kfree(vs);
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rtnl_lock();
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}
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vxlan_sock_release(vs);
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return err;
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}
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@ -1629,11 +1610,7 @@ static void vxlan_dellink(struct net_device *dev, struct list_head *head)
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hlist_del_rcu(&vxlan->hlist);
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list_del(&vxlan->next);
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unregister_netdevice_queue(dev, head);
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if (--vs->refcnt == 0) {
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hlist_del_rcu(&vs->hlist);
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queue_work(vxlan_wq, &vs->del_work);
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}
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vxlan_sock_release(vs);
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}
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static size_t vxlan_get_size(const struct net_device *dev)
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