mpls: Protect net->mpls.platform_label with a per-netns mutex.
MPLS (re)uses RTNL to protect net->mpls.platform_label, but the lock does not need to be RTNL at all. Let's protect net->mpls.platform_label with a dedicated per-netns mutex. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Link: https://patch.msgid.link/20251029173344.2934622-13-kuniyu@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>pull/1354/merge
Kuniyuki Iwashima
Jakub Kicinski
parent
fb2b77b9b1
commit
e833eb2516
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@ -16,6 +16,7 @@ struct netns_mpls {
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int default_ttl;
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size_t platform_labels;
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struct mpls_route __rcu * __rcu *platform_label;
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struct mutex platform_mutex;
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struct ctl_table_header *ctl;
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};
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@ -79,8 +79,8 @@ static struct mpls_route *mpls_route_input(struct net *net, unsigned int index)
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{
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struct mpls_route __rcu **platform_label;
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platform_label = rtnl_dereference(net->mpls.platform_label);
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return rtnl_dereference(platform_label[index]);
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platform_label = mpls_dereference(net, net->mpls.platform_label);
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return mpls_dereference(net, platform_label[index]);
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}
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static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned int index)
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@ -578,10 +578,8 @@ static void mpls_route_update(struct net *net, unsigned index,
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struct mpls_route __rcu **platform_label;
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struct mpls_route *rt;
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ASSERT_RTNL();
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platform_label = rtnl_dereference(net->mpls.platform_label);
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rt = rtnl_dereference(platform_label[index]);
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platform_label = mpls_dereference(net, net->mpls.platform_label);
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rt = mpls_dereference(net, platform_label[index]);
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rcu_assign_pointer(platform_label[index], new);
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mpls_notify_route(net, index, rt, new, info);
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@ -1472,8 +1470,6 @@ static struct mpls_dev *mpls_add_dev(struct net_device *dev)
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int err = -ENOMEM;
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int i;
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ASSERT_RTNL();
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mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
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if (!mdev)
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return ERR_PTR(err);
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@ -1633,6 +1629,8 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
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unsigned int flags;
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int err;
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mutex_lock(&net->mpls.platform_mutex);
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if (event == NETDEV_REGISTER) {
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mdev = mpls_add_dev(dev);
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if (IS_ERR(mdev)) {
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@ -1695,9 +1693,11 @@ static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
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}
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out:
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mutex_unlock(&net->mpls.platform_mutex);
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return NOTIFY_OK;
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err:
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mutex_unlock(&net->mpls.platform_mutex);
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return notifier_from_errno(err);
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}
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@ -1973,6 +1973,7 @@ errout:
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static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct netlink_ext_ack *extack)
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{
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struct net *net = sock_net(skb->sk);
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struct mpls_route_config *cfg;
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int err;
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@ -1984,7 +1985,9 @@ static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
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if (err < 0)
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goto out;
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mutex_lock(&net->mpls.platform_mutex);
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err = mpls_route_del(cfg, extack);
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mutex_unlock(&net->mpls.platform_mutex);
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out:
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kfree(cfg);
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@ -1995,6 +1998,7 @@ out:
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static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct netlink_ext_ack *extack)
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{
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struct net *net = sock_net(skb->sk);
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struct mpls_route_config *cfg;
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int err;
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@ -2006,7 +2010,9 @@ static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
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if (err < 0)
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goto out;
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mutex_lock(&net->mpls.platform_mutex);
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err = mpls_route_add(cfg, extack);
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mutex_unlock(&net->mpls.platform_mutex);
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out:
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kfree(cfg);
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@ -2407,6 +2413,8 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
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u8 n_labels;
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int err;
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mutex_lock(&net->mpls.platform_mutex);
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err = mpls_valid_getroute_req(in_skb, in_nlh, tb, extack);
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if (err < 0)
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goto errout;
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@ -2450,7 +2458,8 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
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goto errout_free;
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}
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return rtnl_unicast(skb, net, portid);
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err = rtnl_unicast(skb, net, portid);
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goto errout;
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}
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if (tb[RTA_NEWDST]) {
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@ -2542,12 +2551,14 @@ static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
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err = rtnl_unicast(skb, net, portid);
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errout:
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mutex_unlock(&net->mpls.platform_mutex);
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return err;
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nla_put_failure:
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nlmsg_cancel(skb, nlh);
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err = -EMSGSIZE;
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errout_free:
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mutex_unlock(&net->mpls.platform_mutex);
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kfree_skb(skb);
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return err;
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}
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@ -2603,9 +2614,10 @@ static int resize_platform_label_table(struct net *net, size_t limit)
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lo->addr_len);
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}
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rtnl_lock();
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mutex_lock(&net->mpls.platform_mutex);
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/* Remember the original table */
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old = rtnl_dereference(net->mpls.platform_label);
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old = mpls_dereference(net, net->mpls.platform_label);
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old_limit = net->mpls.platform_labels;
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/* Free any labels beyond the new table */
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@ -2636,7 +2648,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
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net->mpls.platform_labels = limit;
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rcu_assign_pointer(net->mpls.platform_label, labels);
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rtnl_unlock();
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mutex_unlock(&net->mpls.platform_mutex);
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mpls_rt_free(rt2);
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mpls_rt_free(rt0);
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@ -2709,12 +2721,13 @@ static const struct ctl_table mpls_table[] = {
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},
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};
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static int mpls_net_init(struct net *net)
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static __net_init int mpls_net_init(struct net *net)
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{
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size_t table_size = ARRAY_SIZE(mpls_table);
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struct ctl_table *table;
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int i;
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mutex_init(&net->mpls.platform_mutex);
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net->mpls.platform_labels = 0;
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net->mpls.platform_label = NULL;
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net->mpls.ip_ttl_propagate = 1;
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@ -2740,7 +2753,7 @@ static int mpls_net_init(struct net *net)
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return 0;
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}
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static void mpls_net_exit(struct net *net)
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static __net_exit void mpls_net_exit(struct net *net)
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{
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struct mpls_route __rcu **platform_label;
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size_t platform_labels;
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@ -2760,16 +2773,20 @@ static void mpls_net_exit(struct net *net)
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* As such no additional rcu synchronization is necessary when
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* freeing the platform_label table.
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*/
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rtnl_lock();
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platform_label = rtnl_dereference(net->mpls.platform_label);
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mutex_lock(&net->mpls.platform_mutex);
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platform_label = mpls_dereference(net, net->mpls.platform_label);
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platform_labels = net->mpls.platform_labels;
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for (index = 0; index < platform_labels; index++) {
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struct mpls_route *rt = rtnl_dereference(platform_label[index]);
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RCU_INIT_POINTER(platform_label[index], NULL);
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struct mpls_route *rt;
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rt = mpls_dereference(net, platform_label[index]);
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mpls_notify_route(net, index, rt, NULL, NULL);
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mpls_rt_free(rt);
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}
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rtnl_unlock();
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mutex_unlock(&net->mpls.platform_mutex);
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kvfree(platform_label);
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}
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@ -185,6 +185,11 @@ static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr *
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return result;
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}
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#define mpls_dereference(net, p) \
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rcu_dereference_protected( \
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(p), \
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lockdep_is_held(&(net)->mpls.platform_mutex))
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static inline struct mpls_dev *mpls_dev_rcu(const struct net_device *dev)
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{
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return rcu_dereference(dev->mpls_ptr);
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@ -193,7 +198,7 @@ static inline struct mpls_dev *mpls_dev_rcu(const struct net_device *dev)
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static inline struct mpls_dev *mpls_dev_get(const struct net *net,
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const struct net_device *dev)
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{
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return rcu_dereference_rtnl(dev->mpls_ptr);
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return mpls_dereference(net, dev->mpls_ptr);
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}
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int nla_put_labels(struct sk_buff *skb, int attrtype, u8 labels,
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