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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * net/sched/cls_api.c  Packet classifier API.
  *
  * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  *
  * Changes:
  *
  * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
  */
 
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/skbuff.h>
 #include <linux/init.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
 #include <linux/jhash.h>
 #include <linux/rculist.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/netlink.h>
 #include <net/pkt_sched.h>
 #include <net/pkt_cls.h>
 #include <net/tc_act/tc_pedit.h>
 #include <net/tc_act/tc_mirred.h>
 #include <net/tc_act/tc_vlan.h>
 #include <net/tc_act/tc_tunnel_key.h>
 #include <net/tc_act/tc_csum.h>
 #include <net/tc_act/tc_gact.h>
 #include <net/tc_act/tc_police.h>
 #include <net/tc_act/tc_sample.h>
 #include <net/tc_act/tc_skbedit.h>
 #include <net/tc_act/tc_ct.h>
 #include <net/tc_act/tc_mpls.h>
 #include <net/tc_act/tc_gate.h>
 #include <net/flow_offload.h>
 
 extern const struct nla_policy rtm_tca_policy[TCA_MAX + 1];
 
 /* The list of all installed classifier types */
 static LIST_HEAD(tcf_proto_base);
 
 /* Protects list of registered TC modules. It is pure SMP lock. */
 static DEFINE_RWLOCK(cls_mod_lock);
 
 #ifdef CONFIG_NET_CLS_ACT
 DEFINE_STATIC_KEY_FALSE(tc_skb_ext_tc);
 EXPORT_SYMBOL(tc_skb_ext_tc);
 
 void tc_skb_ext_tc_enable(void)
 {
     static_branch_inc(&tc_skb_ext_tc);
 }
 EXPORT_SYMBOL(tc_skb_ext_tc_enable);
 
 void tc_skb_ext_tc_disable(void)
 {
     static_branch_dec(&tc_skb_ext_tc);
 }
 EXPORT_SYMBOL(tc_skb_ext_tc_disable);
 #endif
 
 static u32 destroy_obj_hashfn(const struct tcf_proto *tp)
 {
     return jhash_3words(tp->chain->index, tp->prio,
                 (__force __u32)tp->protocol, 0);
 }
 
 static void tcf_proto_signal_destroying(struct tcf_chain *chain,
                     struct tcf_proto *tp)
 {
     struct tcf_block *block = chain->block;
 
     mutex_lock(&block->proto_destroy_lock);
     hash_add_rcu(block->proto_destroy_ht, &tp->destroy_ht_node,
              destroy_obj_hashfn(tp));
     mutex_unlock(&block->proto_destroy_lock);
 }
 
 static bool tcf_proto_cmp(const struct tcf_proto *tp1,
               const struct tcf_proto *tp2)
 {
     return tp1->chain->index == tp2->chain->index &&
            tp1->prio == tp2->prio &&
            tp1->protocol == tp2->protocol;
 }
 
 static bool tcf_proto_exists_destroying(struct tcf_chain *chain,
                     struct tcf_proto *tp)
 {
     u32 hash = destroy_obj_hashfn(tp);
     struct tcf_proto *iter;
     bool found = false;
 
     rcu_read_lock();
     hash_for_each_possible_rcu(chain->block->proto_destroy_ht, iter,
                    destroy_ht_node, hash) {
         if (tcf_proto_cmp(tp, iter)) {
             found = true;
             break;
         }
     }
     rcu_read_unlock();
 
     return found;
 }
 
 static void
 tcf_proto_signal_destroyed(struct tcf_chain *chain, struct tcf_proto *tp)
 {
     struct tcf_block *block = chain->block;
 
     mutex_lock(&block->proto_destroy_lock);
     if (hash_hashed(&tp->destroy_ht_node))
         hash_del_rcu(&tp->destroy_ht_node);
     mutex_unlock(&block->proto_destroy_lock);
 }
 
 /* Find classifier type by string name */
 
 static const struct tcf_proto_ops *__tcf_proto_lookup_ops(const char *kind)
 {
     const struct tcf_proto_ops *t, *res = NULL;
 
     if (kind) {
         read_lock(&cls_mod_lock);
         list_for_each_entry(t, &tcf_proto_base, head) {
             if (strcmp(kind, t->kind) == 0) {
                 if (try_module_get(t->owner))
                     res = t;
                 break;
             }
         }
         read_unlock(&cls_mod_lock);
     }
     return res;
 }
 
 static const struct tcf_proto_ops *
 tcf_proto_lookup_ops(const char *kind, bool rtnl_held,
              struct netlink_ext_ack *extack)
 {
     const struct tcf_proto_ops *ops;
 
     ops = __tcf_proto_lookup_ops(kind);
     if (ops)
         return ops;
 #ifdef CONFIG_MODULES
     if (rtnl_held)
         rtnl_unlock();
     request_module("cls_%s", kind);
     if (rtnl_held)
         rtnl_lock();
     ops = __tcf_proto_lookup_ops(kind);
     /* We dropped the RTNL semaphore in order to perform
      * the module load. So, even if we succeeded in loading
      * the module we have to replay the request. We indicate
      * this using -EAGAIN.
      */
     if (ops) {
         module_put(ops->owner);
         return ERR_PTR(-EAGAIN);
     }
 #endif
     NL_SET_ERR_MSG(extack, "TC classifier not found");
     return ERR_PTR(-ENOENT);
 }
 
 /* Register(unregister) new classifier type */
 
 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
 {
     struct tcf_proto_ops *t;
     int rc = -EEXIST;
 
     write_lock(&cls_mod_lock);
     list_for_each_entry(t, &tcf_proto_base, head)
         if (!strcmp(ops->kind, t->kind))
             goto out;
 
     list_add_tail(&ops->head, &tcf_proto_base);
     rc = 0;
 out:
     write_unlock(&cls_mod_lock);
     return rc;
 }
 EXPORT_SYMBOL(register_tcf_proto_ops);
 
 static struct workqueue_struct *tc_filter_wq;
 
 void unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
 {
     struct tcf_proto_ops *t;
     int rc = -ENOENT;
 
     /* Wait for outstanding call_rcu()s, if any, from a
      * tcf_proto_ops's destroy() handler.
      */
     rcu_barrier();
     flush_workqueue(tc_filter_wq);
 
     write_lock(&cls_mod_lock);
     list_for_each_entry(t, &tcf_proto_base, head) {
         if (t == ops) {
             list_del(&t->head);
             rc = 0;
             break;
         }
     }
     write_unlock(&cls_mod_lock);
 
     WARN(rc, "unregister tc filter kind(%s) failed %d\n", ops->kind, rc);
 }
 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 
 bool tcf_queue_work(struct rcu_work *rwork, work_func_t func)
 {
     INIT_RCU_WORK(rwork, func);
     return queue_rcu_work(tc_filter_wq, rwork);
 }
 EXPORT_SYMBOL(tcf_queue_work);
 
 /* Select new prio value from the range, managed by kernel. */
 
 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 {
     u32 first = TC_H_MAKE(0xC0000000U, 0U);
 
     if (tp)
         first = tp->prio - 1;
 
     return TC_H_MAJ(first);
 }
 
 static bool tcf_proto_check_kind(struct nlattr *kind, char *name)
 {
     if (kind)
         return nla_strscpy(name, kind, IFNAMSIZ) < 0;
     memset(name, 0, IFNAMSIZ);
     return false;
 }
 
 static bool tcf_proto_is_unlocked(const char *kind)
 {
     const struct tcf_proto_ops *ops;
     bool ret;
 
     if (strlen(kind) == 0)
         return false;
 
     ops = tcf_proto_lookup_ops(kind, false, NULL);
     /* On error return false to take rtnl lock. Proto lookup/create
      * functions will perform lookup again and properly handle errors.
      */
     if (IS_ERR(ops))
         return false;
 
     ret = !!(ops->flags & TCF_PROTO_OPS_DOIT_UNLOCKED);
     module_put(ops->owner);
     return ret;
 }
 
 static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
                       u32 prio, struct tcf_chain *chain,
                       bool rtnl_held,
                       struct netlink_ext_ack *extack)
 {
     struct tcf_proto *tp;
     int err;
 
     tp = kzalloc(sizeof(*tp), GFP_KERNEL);
     if (!tp)
         return ERR_PTR(-ENOBUFS);
 
     tp->ops = tcf_proto_lookup_ops(kind, rtnl_held, extack);
     if (IS_ERR(tp->ops)) {
         err = PTR_ERR(tp->ops);
         goto errout;
     }
     tp->classify = tp->ops->classify;
     tp->protocol = protocol;
     tp->prio = prio;
     tp->chain = chain;
     spin_lock_init(&tp->lock);
     refcount_set(&tp->refcnt, 1);
 
     err = tp->ops->init(tp);
     if (err) {
         module_put(tp->ops->owner);
         goto errout;
     }
     return tp;
 
 errout:
     kfree(tp);
     return ERR_PTR(err);
 }
 
 static void tcf_proto_get(struct tcf_proto *tp)
 {
     refcount_inc(&tp->refcnt);
 }
 
 static void tcf_chain_put(struct tcf_chain *chain);
 
 static void tcf_proto_destroy(struct tcf_proto *tp, bool rtnl_held,
                   bool sig_destroy, struct netlink_ext_ack *extack)
 {
     tp->ops->destroy(tp, rtnl_held, extack);
     if (sig_destroy)
         tcf_proto_signal_destroyed(tp->chain, tp);
     tcf_chain_put(tp->chain);
     module_put(tp->ops->owner);
     kfree_rcu(tp, rcu);
 }
 
 static void tcf_proto_put(struct tcf_proto *tp, bool rtnl_held,
               struct netlink_ext_ack *extack)
 {
     if (refcount_dec_and_test(&tp->refcnt))
         tcf_proto_destroy(tp, rtnl_held, true, extack);
 }
 
 static bool tcf_proto_check_delete(struct tcf_proto *tp)
 {
     if (tp->ops->delete_empty)
         return tp->ops->delete_empty(tp);
 
     tp->deleting = true;
     return tp->deleting;
 }
 
 static void tcf_proto_mark_delete(struct tcf_proto *tp)
 {
     spin_lock(&tp->lock);
     tp->deleting = true;
     spin_unlock(&tp->lock);
 }
 
 static bool tcf_proto_is_deleting(struct tcf_proto *tp)
 {
     bool deleting;
 
     spin_lock(&tp->lock);
     deleting = tp->deleting;
     spin_unlock(&tp->lock);
 
     return deleting;
 }
 
 #define ASSERT_BLOCK_LOCKED(block)                  \
     lockdep_assert_held(&(block)->lock)
 
 struct tcf_filter_chain_list_item {
     struct list_head list;
     tcf_chain_head_change_t *chain_head_change;
     void *chain_head_change_priv;
 };
 
 static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
                       u32 chain_index)
 {
     struct tcf_chain *chain;
 
     ASSERT_BLOCK_LOCKED(block);
 
     chain = kzalloc(sizeof(*chain), GFP_KERNEL);
     if (!chain)
         return NULL;
     list_add_tail_rcu(&chain->list, &block->chain_list);
     mutex_init(&chain->filter_chain_lock);
     chain->block = block;
     chain->index = chain_index;
     chain->refcnt = 1;
     if (!chain->index)
         block->chain0.chain = chain;
     return chain;
 }
 
 static void tcf_chain_head_change_item(struct tcf_filter_chain_list_item *item,
                        struct tcf_proto *tp_head)
 {
     if (item->chain_head_change)
         item->chain_head_change(tp_head, item->chain_head_change_priv);
 }
 
 static void tcf_chain0_head_change(struct tcf_chain *chain,
                    struct tcf_proto *tp_head)
 {
     struct tcf_filter_chain_list_item *item;
     struct tcf_block *block = chain->block;
 
     if (chain->index)
         return;
 
     mutex_lock(&block->lock);
     list_for_each_entry(item, &block->chain0.filter_chain_list, list)
         tcf_chain_head_change_item(item, tp_head);
     mutex_unlock(&block->lock);
 }
 
 /* Returns true if block can be safely freed. */
 
 static bool tcf_chain_detach(struct tcf_chain *chain)
 {
     struct tcf_block *block = chain->block;
 
     ASSERT_BLOCK_LOCKED(block);
 
     list_del_rcu(&chain->list);
     if (!chain->index)
         block->chain0.chain = NULL;
 
     if (list_empty(&block->chain_list) &&
         refcount_read(&block->refcnt) == 0)
         return true;
 
     return false;
 }
 
 static void tcf_block_destroy(struct tcf_block *block)
 {
     mutex_destroy(&block->lock);
     mutex_destroy(&block->proto_destroy_lock);
     kfree_rcu(block, rcu);
 }
 
 static void tcf_chain_destroy(struct tcf_chain *chain, bool free_block)
 {
     struct tcf_block *block = chain->block;
 
     mutex_destroy(&chain->filter_chain_lock);
     kfree_rcu(chain, rcu);
     if (free_block)
         tcf_block_destroy(block);
 }
 
 static void tcf_chain_hold(struct tcf_chain *chain)
 {
     ASSERT_BLOCK_LOCKED(chain->block);
 
     ++chain->refcnt;
 }
 
 static bool tcf_chain_held_by_acts_only(struct tcf_chain *chain)
 {
     ASSERT_BLOCK_LOCKED(chain->block);
 
     /* In case all the references are action references, this
      * chain should not be shown to the user.
      */
     return chain->refcnt == chain->action_refcnt;
 }
 
 static struct tcf_chain *tcf_chain_lookup(struct tcf_block *block,
                       u32 chain_index)
 {
     struct tcf_chain *chain;
 
     ASSERT_BLOCK_LOCKED(block);
 
     list_for_each_entry(chain, &block->chain_list, list) {
         if (chain->index == chain_index)
             return chain;
     }
     return NULL;
 }
 
 #if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
 static struct tcf_chain *tcf_chain_lookup_rcu(const struct tcf_block *block,
                           u32 chain_index)
 {
     struct tcf_chain *chain;
 
     list_for_each_entry_rcu(chain, &block->chain_list, list) {
         if (chain->index == chain_index)
             return chain;
     }
     return NULL;
 }
 #endif
 
 static int tc_chain_notify(struct tcf_chain *chain, struct sk_buff *oskb,
                u32 seq, u16 flags, int event, bool unicast);
 
 static struct tcf_chain *__tcf_chain_get(struct tcf_block *block,
                      u32 chain_index, bool create,
                      bool by_act)
 {
     struct tcf_chain *chain = NULL;
     bool is_first_reference;
 
     mutex_lock(&block->lock);
     chain = tcf_chain_lookup(block, chain_index);
     if (chain) {
         tcf_chain_hold(chain);
     } else {
         if (!create)
             goto errout;
         chain = tcf_chain_create(block, chain_index);
         if (!chain)
             goto errout;
     }
 
     if (by_act)
         ++chain->action_refcnt;
     is_first_reference = chain->refcnt - chain->action_refcnt == 1;
     mutex_unlock(&block->lock);
 
     /* Send notification only in case we got the first
      * non-action reference. Until then, the chain acts only as
      * a placeholder for actions pointing to it and user ought
      * not know about them.
      */
     if (is_first_reference && !by_act)
         tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
                 RTM_NEWCHAIN, false);
 
     return chain;
 
 errout:
     mutex_unlock(&block->lock);
     return chain;
 }
 
 static struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
                        bool create)
 {
     return __tcf_chain_get(block, chain_index, create, false);
 }
 
 struct tcf_chain *tcf_chain_get_by_act(struct tcf_block *block, u32 chain_index)
 {
     return __tcf_chain_get(block, chain_index, true, true);
 }
 EXPORT_SYMBOL(tcf_chain_get_by_act);
 
 static void tc_chain_tmplt_del(const struct tcf_proto_ops *tmplt_ops,
                    void *tmplt_priv);
 static int tc_chain_notify_delete(const struct tcf_proto_ops *tmplt_ops,
                   void *tmplt_priv, u32 chain_index,
                   struct tcf_block *block, struct sk_buff *oskb,
                   u32 seq, u16 flags, bool unicast);
 
 static void __tcf_chain_put(struct tcf_chain *chain, bool by_act,
                 bool explicitly_created)
 {
     struct tcf_block *block = chain->block;
     const struct tcf_proto_ops *tmplt_ops;
     bool free_block = false;
     unsigned int refcnt;
     void *tmplt_priv;
 
     mutex_lock(&block->lock);
     if (explicitly_created) {
         if (!chain->explicitly_created) {
             mutex_unlock(&block->lock);
             return;
         }
         chain->explicitly_created = false;
     }
 
     if (by_act)
         chain->action_refcnt--;
 
     /* tc_chain_notify_delete can't be called while holding block lock.
      * However, when block is unlocked chain can be changed concurrently, so
      * save these to temporary variables.
      */
     refcnt = --chain->refcnt;
     tmplt_ops = chain->tmplt_ops;
     tmplt_priv = chain->tmplt_priv;
 
     /* The last dropped non-action reference will trigger notification. */
     if (refcnt - chain->action_refcnt == 0 && !by_act) {
         tc_chain_notify_delete(tmplt_ops, tmplt_priv, chain->index,
                        block, NULL, 0, 0, false);
         /* Last reference to chain, no need to lock. */
         chain->flushing = false;
     }
 
     if (refcnt == 0)
         free_block = tcf_chain_detach(chain);
     mutex_unlock(&block->lock);
 
     if (refcnt == 0) {
         tc_chain_tmplt_del(tmplt_ops, tmplt_priv);
         tcf_chain_destroy(chain, free_block);
     }
 }
 
 static void tcf_chain_put(struct tcf_chain *chain)
 {
     __tcf_chain_put(chain, false, false);
 }
 
 void tcf_chain_put_by_act(struct tcf_chain *chain)
 {
     __tcf_chain_put(chain, true, false);
 }
 EXPORT_SYMBOL(tcf_chain_put_by_act);
 
 static void tcf_chain_put_explicitly_created(struct tcf_chain *chain)
 {
     __tcf_chain_put(chain, false, true);
 }
 
 static void tcf_chain_flush(struct tcf_chain *chain, bool rtnl_held)
 {
     struct tcf_proto *tp, *tp_next;
 
     mutex_lock(&chain->filter_chain_lock);
     tp = tcf_chain_dereference(chain->filter_chain, chain);
     while (tp) {
         tp_next = rcu_dereference_protected(tp->next, 1);
         tcf_proto_signal_destroying(chain, tp);
         tp = tp_next;
     }
     tp = tcf_chain_dereference(chain->filter_chain, chain);
     RCU_INIT_POINTER(chain->filter_chain, NULL);
     tcf_chain0_head_change(chain, NULL);
     chain->flushing = true;
     mutex_unlock(&chain->filter_chain_lock);
 
     while (tp) {
         tp_next = rcu_dereference_protected(tp->next, 1);
         tcf_proto_put(tp, rtnl_held, NULL);
         tp = tp_next;
     }
 }
 
 static int tcf_block_setup(struct tcf_block *block,
                struct flow_block_offload *bo);
 
 static void tcf_block_offload_init(struct flow_block_offload *bo,
                    struct net_device *dev, struct Qdisc *sch,
                    enum flow_block_command command,
                    enum flow_block_binder_type binder_type,
                    struct flow_block *flow_block,
                    bool shared, struct netlink_ext_ack *extack)
 {
     bo->net = dev_net(dev);
     bo->command = command;
     bo->binder_type = binder_type;
     bo->block = flow_block;
     bo->block_shared = shared;
     bo->extack = extack;
     bo->sch = sch;
     bo->cb_list_head = &flow_block->cb_list;
     INIT_LIST_HEAD(&bo->cb_list);
 }
 
 static void tcf_block_unbind(struct tcf_block *block,
                  struct flow_block_offload *bo);
 
 static void tc_block_indr_cleanup(struct flow_block_cb *block_cb)
 {
     struct tcf_block *block = block_cb->indr.data;
     struct net_device *dev = block_cb->indr.dev;
     struct Qdisc *sch = block_cb->indr.sch;
     struct netlink_ext_ack extack = {};
     struct flow_block_offload bo = {};
 
     tcf_block_offload_init(&bo, dev, sch, FLOW_BLOCK_UNBIND,
                    block_cb->indr.binder_type,
                    &block->flow_block, tcf_block_shared(block),
                    &extack);
     rtnl_lock();
     down_write(&block->cb_lock);
     list_del(&block_cb->driver_list);
     list_move(&block_cb->list, &bo.cb_list);
     tcf_block_unbind(block, &bo);
     up_write(&block->cb_lock);
     rtnl_unlock();
 }
 
 static bool tcf_block_offload_in_use(struct tcf_block *block)
 {
     return atomic_read(&block->offloadcnt);
 }
 
 static int tcf_block_offload_cmd(struct tcf_block *block,
                  struct net_device *dev, struct Qdisc *sch,
                  struct tcf_block_ext_info *ei,
                  enum flow_block_command command,
                  struct netlink_ext_ack *extack)
 {
     struct flow_block_offload bo = {};
 
     tcf_block_offload_init(&bo, dev, sch, command, ei->binder_type,
                    &block->flow_block, tcf_block_shared(block),
                    extack);
 
     if (dev->netdev_ops->ndo_setup_tc) {
         int err;
 
         err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_BLOCK, &bo);
         if (err < 0) {
             if (err != -EOPNOTSUPP)
                 NL_SET_ERR_MSG(extack, "Driver ndo_setup_tc failed");
             return err;
         }
 
         return tcf_block_setup(block, &bo);
     }
 
     flow_indr_dev_setup_offload(dev, sch, TC_SETUP_BLOCK, block, &bo,
                     tc_block_indr_cleanup);
     tcf_block_setup(block, &bo);
 
     return -EOPNOTSUPP;
 }
 
 static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
                   struct tcf_block_ext_info *ei,
                   struct netlink_ext_ack *extack)
 {
     struct net_device *dev = q->dev_queue->dev;
     int err;
 
     down_write(&block->cb_lock);
 
     /* If tc offload feature is disabled and the block we try to bind
      * to already has some offloaded filters, forbid to bind.
      */
     if (dev->netdev_ops->ndo_setup_tc &&
         !tc_can_offload(dev) &&
         tcf_block_offload_in_use(block)) {
         NL_SET_ERR_MSG(extack, "Bind to offloaded block failed as dev has offload disabled");
         err = -EOPNOTSUPP;
         goto err_unlock;
     }
 
     err = tcf_block_offload_cmd(block, dev, q, ei, FLOW_BLOCK_BIND, extack);
     if (err == -EOPNOTSUPP)
         goto no_offload_dev_inc;
     if (err)
         goto err_unlock;
 
     up_write(&block->cb_lock);
     return 0;
 
 no_offload_dev_inc:
     if (tcf_block_offload_in_use(block))
         goto err_unlock;
 
     err = 0;
     block->nooffloaddevcnt++;
 err_unlock:
     up_write(&block->cb_lock);
     return err;
 }
 
 static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
                      struct tcf_block_ext_info *ei)
 {
     struct net_device *dev = q->dev_queue->dev;
     int err;
 
     down_write(&block->cb_lock);
     err = tcf_block_offload_cmd(block, dev, q, ei, FLOW_BLOCK_UNBIND, NULL);
     if (err == -EOPNOTSUPP)
         goto no_offload_dev_dec;
     up_write(&block->cb_lock);
     return;
 
 no_offload_dev_dec:
     WARN_ON(block->nooffloaddevcnt-- == 0);
     up_write(&block->cb_lock);
 }
 
 static int
 tcf_chain0_head_change_cb_add(struct tcf_block *block,
                   struct tcf_block_ext_info *ei,
                   struct netlink_ext_ack *extack)
 {
     struct tcf_filter_chain_list_item *item;
     struct tcf_chain *chain0;
 
     item = kmalloc(sizeof(*item), GFP_KERNEL);
     if (!item) {
         NL_SET_ERR_MSG(extack, "Memory allocation for head change callback item failed");
         return -ENOMEM;
     }
     item->chain_head_change = ei->chain_head_change;
     item->chain_head_change_priv = ei->chain_head_change_priv;
 
     mutex_lock(&block->lock);
     chain0 = block->chain0.chain;
     if (chain0)
         tcf_chain_hold(chain0);
     else
         list_add(&item->list, &block->chain0.filter_chain_list);
     mutex_unlock(&block->lock);
 
     if (chain0) {
         struct tcf_proto *tp_head;
 
         mutex_lock(&chain0->filter_chain_lock);
 
         tp_head = tcf_chain_dereference(chain0->filter_chain, chain0);
         if (tp_head)
             tcf_chain_head_change_item(item, tp_head);
 
         mutex_lock(&block->lock);
         list_add(&item->list, &block->chain0.filter_chain_list);
         mutex_unlock(&block->lock);
 
         mutex_unlock(&chain0->filter_chain_lock);
         tcf_chain_put(chain0);
     }
 
     return 0;
 }
 
 static void
 tcf_chain0_head_change_cb_del(struct tcf_block *block,
                   struct tcf_block_ext_info *ei)
 {
     struct tcf_filter_chain_list_item *item;
 
     mutex_lock(&block->lock);
     list_for_each_entry(item, &block->chain0.filter_chain_list, list) {
         if ((!ei->chain_head_change && !ei->chain_head_change_priv) ||
             (item->chain_head_change == ei->chain_head_change &&
              item->chain_head_change_priv == ei->chain_head_change_priv)) {
             if (block->chain0.chain)
                 tcf_chain_head_change_item(item, NULL);
             list_del(&item->list);
             mutex_unlock(&block->lock);
 
             kfree(item);
             return;
         }
     }
     mutex_unlock(&block->lock);
     WARN_ON(1);
 }
 
 struct tcf_net {
     spinlock_t idr_lock; /* Protects idr */
     struct idr idr;
 };
 
 static unsigned int tcf_net_id;
 
 static int tcf_block_insert(struct tcf_block *block, struct net *net,
                 struct netlink_ext_ack *extack)
 {
     struct tcf_net *tn = net_generic(net, tcf_net_id);
     int err;
 
     idr_preload(GFP_KERNEL);
     spin_lock(&tn->idr_lock);
     err = idr_alloc_u32(&tn->idr, block, &block->index, block->index,
                 GFP_NOWAIT);
     spin_unlock(&tn->idr_lock);
     idr_preload_end();
 
     return err;
 }
 
 static void tcf_block_remove(struct tcf_block *block, struct net *net)
 {
     struct tcf_net *tn = net_generic(net, tcf_net_id);
 
     spin_lock(&tn->idr_lock);
     idr_remove(&tn->idr, block->index);
     spin_unlock(&tn->idr_lock);
 }
 
 static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
                       u32 block_index,
                       struct netlink_ext_ack *extack)
 {
     struct tcf_block *block;
 
     block = kzalloc(sizeof(*block), GFP_KERNEL);
     if (!block) {
         NL_SET_ERR_MSG(extack, "Memory allocation for block failed");
         return ERR_PTR(-ENOMEM);
     }
     mutex_init(&block->lock);
     mutex_init(&block->proto_destroy_lock);
     init_rwsem(&block->cb_lock);
     flow_block_init(&block->flow_block);
     INIT_LIST_HEAD(&block->chain_list);
     INIT_LIST_HEAD(&block->owner_list);
     INIT_LIST_HEAD(&block->chain0.filter_chain_list);
 
     refcount_set(&block->refcnt, 1);
     block->net = net;
     block->index = block_index;
 
     /* Don't store q pointer for blocks which are shared */
     if (!tcf_block_shared(block))
         block->q = q;
     return block;
 }
 
 static struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index)
 {
     struct tcf_net *tn = net_generic(net, tcf_net_id);
 
     return idr_find(&tn->idr, block_index);
 }
 
 static struct tcf_block *tcf_block_refcnt_get(struct net *net, u32 block_index)
 {
     struct tcf_block *block;
 
     rcu_read_lock();
     block = tcf_block_lookup(net, block_index);
     if (block && !refcount_inc_not_zero(&block->refcnt))
         block = NULL;
     rcu_read_unlock();
 
     return block;
 }
 
 static struct tcf_chain *
 __tcf_get_next_chain(struct tcf_block *block, struct tcf_chain *chain)
 {
     mutex_lock(&block->lock);
     if (chain)
         chain = list_is_last(&chain->list, &block->chain_list) ?
             NULL : list_next_entry(chain, list);
     else
         chain = list_first_entry_or_null(&block->chain_list,
                          struct tcf_chain, list);
 
     /* skip all action-only chains */
     while (chain && tcf_chain_held_by_acts_only(chain))
         chain = list_is_last(&chain->list, &block->chain_list) ?
             NULL : list_next_entry(chain, list);
 
     if (chain)
         tcf_chain_hold(chain);
     mutex_unlock(&block->lock);
 
     return chain;
 }
 
 /* Function to be used by all clients that want to iterate over all chains on
  * block. It properly obtains block->lock and takes reference to chain before
  * returning it. Users of this function must be tolerant to concurrent chain
  * insertion/deletion or ensure that no concurrent chain modification is
  * possible. Note that all netlink dump callbacks cannot guarantee to provide
  * consistent dump because rtnl lock is released each time skb is filled with
  * data and sent to user-space.
  */
 
 struct tcf_chain *
 tcf_get_next_chain(struct tcf_block *block, struct tcf_chain *chain)
 {
     struct tcf_chain *chain_next = __tcf_get_next_chain(block, chain);
 
     if (chain)
         tcf_chain_put(chain);
 
     return chain_next;
 }
 EXPORT_SYMBOL(tcf_get_next_chain);
 
 static struct tcf_proto *
 __tcf_get_next_proto(struct tcf_chain *chain, struct tcf_proto *tp)
 {
     u32 prio = 0;
 
     ASSERT_RTNL();
     mutex_lock(&chain->filter_chain_lock);
 
     if (!tp) {
         tp = tcf_chain_dereference(chain->filter_chain, chain);
     } else if (tcf_proto_is_deleting(tp)) {
         /* 'deleting' flag is set and chain->filter_chain_lock was
          * unlocked, which means next pointer could be invalid. Restart
          * search.
          */
         prio = tp->prio + 1;
         tp = tcf_chain_dereference(chain->filter_chain, chain);
 
         for (; tp; tp = tcf_chain_dereference(tp->next, chain))
             if (!tp->deleting && tp->prio >= prio)
                 break;
     } else {
         tp = tcf_chain_dereference(tp->next, chain);
     }
 
     if (tp)
         tcf_proto_get(tp);
 
     mutex_unlock(&chain->filter_chain_lock);
 
     return tp;
 }
 
 /* Function to be used by all clients that want to iterate over all tp's on
  * chain. Users of this function must be tolerant to concurrent tp
  * insertion/deletion or ensure that no concurrent chain modification is
  * possible. Note that all netlink dump callbacks cannot guarantee to provide
  * consistent dump because rtnl lock is released each time skb is filled with
  * data and sent to user-space.
  */
 
 struct tcf_proto *
 tcf_get_next_proto(struct tcf_chain *chain, struct tcf_proto *tp)
 {
     struct tcf_proto *tp_next = __tcf_get_next_proto(chain, tp);
 
     if (tp)
         tcf_proto_put(tp, true, NULL);
 
     return tp_next;
 }
 EXPORT_SYMBOL(tcf_get_next_proto);
 
 static void tcf_block_flush_all_chains(struct tcf_block *block, bool rtnl_held)
 {
     struct tcf_chain *chain;
 
     /* Last reference to block. At this point chains cannot be added or
      * removed concurrently.
      */
     for (chain = tcf_get_next_chain(block, NULL);
          chain;
          chain = tcf_get_next_chain(block, chain)) {
         tcf_chain_put_explicitly_created(chain);
         tcf_chain_flush(chain, rtnl_held);
     }
 }
 
 /* Lookup Qdisc and increments its reference counter.
  * Set parent, if necessary.
  */
 
 static int __tcf_qdisc_find(struct net *net, struct Qdisc **q,
                 u32 *parent, int ifindex, bool rtnl_held,
                 struct netlink_ext_ack *extack)
 {
     const struct Qdisc_class_ops *cops;
     struct net_device *dev;
     int err = 0;
 
     if (ifindex == TCM_IFINDEX_MAGIC_BLOCK)
         return 0;
 
     rcu_read_lock();
 
     /* Find link */
     dev = dev_get_by_index_rcu(net, ifindex);
     if (!dev) {
         rcu_read_unlock();
         return -ENODEV;
     }
 
     /* Find qdisc */
     if (!*parent) {
         *q = rcu_dereference(dev->qdisc);
         *parent = (*q)->handle;
     } else {
         *q = qdisc_lookup_rcu(dev, TC_H_MAJ(*parent));
         if (!*q) {
             NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");
             err = -EINVAL;
             goto errout_rcu;
         }
     }
 
     *q = qdisc_refcount_inc_nz(*q);
     if (!*q) {
         NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");
         err = -EINVAL;
         goto errout_rcu;
     }
 
     /* Is it classful? */
     cops = (*q)->ops->cl_ops;
     if (!cops) {
         NL_SET_ERR_MSG(extack, "Qdisc not classful");
         err = -EINVAL;
         goto errout_qdisc;
     }
 
     if (!cops->tcf_block) {
         NL_SET_ERR_MSG(extack, "Class doesn't support blocks");
         err = -EOPNOTSUPP;
         goto errout_qdisc;
     }
 
 errout_rcu:
     /* At this point we know that qdisc is not noop_qdisc,
      * which means that qdisc holds a reference to net_device
      * and we hold a reference to qdisc, so it is safe to release
      * rcu read lock.
      */
     rcu_read_unlock();
     return err;
 
 errout_qdisc:
     rcu_read_unlock();
 
     if (rtnl_held)
         qdisc_put(*q);
     else
         qdisc_put_unlocked(*q);
     *q = NULL;
 
     return err;
 }
 
 static int __tcf_qdisc_cl_find(struct Qdisc *q, u32 parent, unsigned long *cl,
                    int ifindex, struct netlink_ext_ack *extack)
 {
     if (ifindex == TCM_IFINDEX_MAGIC_BLOCK)
         return 0;
 
     /* Do we search for filter, attached to class? */
     if (TC_H_MIN(parent)) {
         const struct Qdisc_class_ops *cops = q->ops->cl_ops;
 
         *cl = cops->find(q, parent);
         if (*cl == 0) {
             NL_SET_ERR_MSG(extack, "Specified class doesn't exist");
             return -ENOENT;
         }
     }
 
     return 0;
 }
 
 static struct tcf_block *__tcf_block_find(struct net *net, struct Qdisc *q,
                       unsigned long cl, int ifindex,
                       u32 block_index,
                       struct netlink_ext_ack *extack)
 {
     struct tcf_block *block;
 
     if (ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
         block = tcf_block_refcnt_get(net, block_index);
         if (!block) {
             NL_SET_ERR_MSG(extack, "Block of given index was not found");
             return ERR_PTR(-EINVAL);
         }
     } else {
         const struct Qdisc_class_ops *cops = q->ops->cl_ops;
 
         block = cops->tcf_block(q, cl, extack);
         if (!block)
             return ERR_PTR(-EINVAL);
 
         if (tcf_block_shared(block)) {
             NL_SET_ERR_MSG(extack, "This filter block is shared. Please use the block index to manipulate the filters");
             return ERR_PTR(-EOPNOTSUPP);
         }
 
         /* Always take reference to block in order to support execution
          * of rules update path of cls API without rtnl lock. Caller
          * must release block when it is finished using it. 'if' block
          * of this conditional obtain reference to block by calling
          * tcf_block_refcnt_get().
          */
         refcount_inc(&block->refcnt);
     }
 
     return block;
 }
 
 static void __tcf_block_put(struct tcf_block *block, struct Qdisc *q,
                 struct tcf_block_ext_info *ei, bool rtnl_held)
 {
     if (refcount_dec_and_mutex_lock(&block->refcnt, &block->lock)) {
         /* Flushing/putting all chains will cause the block to be
          * deallocated when last chain is freed. However, if chain_list
          * is empty, block has to be manually deallocated. After block
          * reference counter reached 0, it is no longer possible to
          * increment it or add new chains to block.
          */
         bool free_block = list_empty(&block->chain_list);
 
         mutex_unlock(&block->lock);
         if (tcf_block_shared(block))
             tcf_block_remove(block, block->net);
 
         if (q)
             tcf_block_offload_unbind(block, q, ei);
 
         if (free_block)
             tcf_block_destroy(block);
         else
             tcf_block_flush_all_chains(block, rtnl_held);
     } else if (q) {
         tcf_block_offload_unbind(block, q, ei);
     }
 }
 
 static void tcf_block_refcnt_put(struct tcf_block *block, bool rtnl_held)
 {
     __tcf_block_put(block, NULL, NULL, rtnl_held);
 }
 
 /* Find tcf block.
  * Set q, parent, cl when appropriate.
  */
 
 static struct tcf_block *tcf_block_find(struct net *net, struct Qdisc **q,
                     u32 *parent, unsigned long *cl,
                     int ifindex, u32 block_index,
                     struct netlink_ext_ack *extack)
 {
     struct tcf_block *block;
     int err = 0;
 
     ASSERT_RTNL();
 
     err = __tcf_qdisc_find(net, q, parent, ifindex, true, extack);
     if (err)
         goto errout;
 
     err = __tcf_qdisc_cl_find(*q, *parent, cl, ifindex, extack);
     if (err)
         goto errout_qdisc;
 
     block = __tcf_block_find(net, *q, *cl, ifindex, block_index, extack);
     if (IS_ERR(block)) {
         err = PTR_ERR(block);
         goto errout_qdisc;
     }
 
     return block;
 
 errout_qdisc:
     if (*q)
         qdisc_put(*q);
 errout:
     *q = NULL;
     return ERR_PTR(err);
 }
 
 static void tcf_block_release(struct Qdisc *q, struct tcf_block *block,
                   bool rtnl_held)
 {
     if (!IS_ERR_OR_NULL(block))
         tcf_block_refcnt_put(block, rtnl_held);
 
     if (q) {
         if (rtnl_held)
             qdisc_put(q);
         else
             qdisc_put_unlocked(q);
     }
 }
 
 struct tcf_block_owner_item {
     struct list_head list;
     struct Qdisc *q;
     enum flow_block_binder_type binder_type;
 };
 
 static void
 tcf_block_owner_netif_keep_dst(struct tcf_block *block,
                    struct Qdisc *q,
                    enum flow_block_binder_type binder_type)
 {
     if (block->keep_dst &&
         binder_type != FLOW_BLOCK_BINDER_TYPE_CLSACT_INGRESS &&
         binder_type != FLOW_BLOCK_BINDER_TYPE_CLSACT_EGRESS)
         netif_keep_dst(qdisc_dev(q));
 }
 
 void tcf_block_netif_keep_dst(struct tcf_block *block)
 {
     struct tcf_block_owner_item *item;
 
     block->keep_dst = true;
     list_for_each_entry(item, &block->owner_list, list)
         tcf_block_owner_netif_keep_dst(block, item->q,
                            item->binder_type);
 }
 EXPORT_SYMBOL(tcf_block_netif_keep_dst);
 
 static int tcf_block_owner_add(struct tcf_block *block,
                    struct Qdisc *q,
                    enum flow_block_binder_type binder_type)
 {
     struct tcf_block_owner_item *item;
 
     item = kmalloc(sizeof(*item), GFP_KERNEL);
     if (!item)
         return -ENOMEM;
     item->q = q;
     item->binder_type = binder_type;
     list_add(&item->list, &block->owner_list);
     return 0;
 }
 
 static void tcf_block_owner_del(struct tcf_block *block,
                 struct Qdisc *q,
                 enum flow_block_binder_type binder_type)
 {
     struct tcf_block_owner_item *item;
 
     list_for_each_entry(item, &block->owner_list, list) {
         if (item->q == q && item->binder_type == binder_type) {
             list_del(&item->list);
             kfree(item);
             return;
         }
     }
     WARN_ON(1);
 }
 
 int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
               struct tcf_block_ext_info *ei,
               struct netlink_ext_ack *extack)
 {
     struct net *net = qdisc_net(q);
     struct tcf_block *block = NULL;
     int err;
 
     if (ei->block_index)
         /* block_index not 0 means the shared block is requested */
         block = tcf_block_refcnt_get(net, ei->block_index);
 
     if (!block) {
         block = tcf_block_create(net, q, ei->block_index, extack);
         if (IS_ERR(block))
             return PTR_ERR(block);
         if (tcf_block_shared(block)) {
             err = tcf_block_insert(block, net, extack);
             if (err)
                 goto err_block_insert;
         }
     }
 
     err = tcf_block_owner_add(block, q, ei->binder_type);
     if (err)
         goto err_block_owner_add;
 
     tcf_block_owner_netif_keep_dst(block, q, ei->binder_type);
 
     err = tcf_chain0_head_change_cb_add(block, ei, extack);
     if (err)
         goto err_chain0_head_change_cb_add;
 
     err = tcf_block_offload_bind(block, q, ei, extack);
     if (err)
         goto err_block_offload_bind;
 
     *p_block = block;
     return 0;
 
 err_block_offload_bind:
     tcf_chain0_head_change_cb_del(block, ei);
 err_chain0_head_change_cb_add:
     tcf_block_owner_del(block, q, ei->binder_type);
 err_block_owner_add:
 err_block_insert:
     tcf_block_refcnt_put(block, true);
     return err;
 }
 EXPORT_SYMBOL(tcf_block_get_ext);
 
 static void tcf_chain_head_change_dflt(struct tcf_proto *tp_head, void *priv)
 {
     struct tcf_proto __rcu **p_filter_chain = priv;
 
     rcu_assign_pointer(*p_filter_chain, tp_head);
 }
 
 int tcf_block_get(struct tcf_block **p_block,
           struct tcf_proto __rcu **p_filter_chain, struct Qdisc *q,
           struct netlink_ext_ack *extack)
 {
     struct tcf_block_ext_info ei = {
         .chain_head_change = tcf_chain_head_change_dflt,
         .chain_head_change_priv = p_filter_chain,
     };
 
     WARN_ON(!p_filter_chain);
     return tcf_block_get_ext(p_block, q, &ei, extack);
 }
 EXPORT_SYMBOL(tcf_block_get);
 
 /* XXX: Standalone actions are not allowed to jump to any chain, and bound
  * actions should be all removed after flushing.
  */
 void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q,
                struct tcf_block_ext_info *ei)
 {
     if (!block)
         return;
     tcf_chain0_head_change_cb_del(block, ei);
     tcf_block_owner_del(block, q, ei->binder_type);
 
     __tcf_block_put(block, q, ei, true);
 }
 EXPORT_SYMBOL(tcf_block_put_ext);
 
 void tcf_block_put(struct tcf_block *block)
 {
     struct tcf_block_ext_info ei = {0, };
 
     if (!block)
         return;
     tcf_block_put_ext(block, block->q, &ei);
 }
 
 EXPORT_SYMBOL(tcf_block_put);
 
 static int
 tcf_block_playback_offloads(struct tcf_block *block, flow_setup_cb_t *cb,
                 void *cb_priv, bool add, bool offload_in_use,
                 struct netlink_ext_ack *extack)
 {
     struct tcf_chain *chain, *chain_prev;
     struct tcf_proto *tp, *tp_prev;
     int err;
 
     lockdep_assert_held(&block->cb_lock);
 
     for (chain = __tcf_get_next_chain(block, NULL);
          chain;
          chain_prev = chain,
              chain = __tcf_get_next_chain(block, chain),
              tcf_chain_put(chain_prev)) {
         for (tp = __tcf_get_next_proto(chain, NULL); tp;
              tp_prev = tp,
                  tp = __tcf_get_next_proto(chain, tp),
                  tcf_proto_put(tp_prev, true, NULL)) {
             if (tp->ops->reoffload) {
                 err = tp->ops->reoffload(tp, add, cb, cb_priv,
                              extack);
                 if (err && add)
                     goto err_playback_remove;
             } else if (add && offload_in_use) {
                 err = -EOPNOTSUPP;
                 NL_SET_ERR_MSG(extack, "Filter HW offload failed - classifier without re-offloading support");
                 goto err_playback_remove;
             }
         }
     }
 
     return 0;
 
 err_playback_remove:
     tcf_proto_put(tp, true, NULL);
     tcf_chain_put(chain);
     tcf_block_playback_offloads(block, cb, cb_priv, false, offload_in_use,
                     extack);
     return err;
 }
 
 static int tcf_block_bind(struct tcf_block *block,
               struct flow_block_offload *bo)
 {
     struct flow_block_cb *block_cb, *next;
     int err, i = 0;
 
     lockdep_assert_held(&block->cb_lock);
 
     list_for_each_entry(block_cb, &bo->cb_list, list) {
         err = tcf_block_playback_offloads(block, block_cb->cb,
                           block_cb->cb_priv, true,
                           tcf_block_offload_in_use(block),
                           bo->extack);
         if (err)
             goto err_unroll;
         if (!bo->unlocked_driver_cb)
             block->lockeddevcnt++;
 
         i++;
     }
     list_splice(&bo->cb_list, &block->flow_block.cb_list);
 
     return 0;
 
 err_unroll:
     list_for_each_entry_safe(block_cb, next, &bo->cb_list, list) {
         if (i-- > 0) {
             list_del(&block_cb->list);
             tcf_block_playback_offloads(block, block_cb->cb,
                             block_cb->cb_priv, false,
                             tcf_block_offload_in_use(block),
                             NULL);
             if (!bo->unlocked_driver_cb)
                 block->lockeddevcnt--;
         }
         flow_block_cb_free(block_cb);
     }
 
     return err;
 }
 
 static void tcf_block_unbind(struct tcf_block *block,
                  struct flow_block_offload *bo)
 {
     struct flow_block_cb *block_cb, *next;
 
     lockdep_assert_held(&block->cb_lock);
 
     list_for_each_entry_safe(block_cb, next, &bo->cb_list, list) {
         tcf_block_playback_offloads(block, block_cb->cb,
                         block_cb->cb_priv, false,
                         tcf_block_offload_in_use(block),
                         NULL);
         list_del(&block_cb->list);
         flow_block_cb_free(block_cb);
         if (!bo->unlocked_driver_cb)
             block->lockeddevcnt--;
     }
 }
 
 static int tcf_block_setup(struct tcf_block *block,
                struct flow_block_offload *bo)
 {
     int err;
 
     switch (bo->command) {
     case FLOW_BLOCK_BIND:
         err = tcf_block_bind(block, bo);
         break;
     case FLOW_BLOCK_UNBIND:
         err = 0;
         tcf_block_unbind(block, bo);
         break;
     default:
         WARN_ON_ONCE(1);
         err = -EOPNOTSUPP;
     }
 
     return err;
 }
 
 /* Main classifier routine: scans classifier chain attached
  * to this qdisc, (optionally) tests for protocol and asks
  * specific classifiers.
  */
 static inline int __tcf_classify(struct sk_buff *skb,
                  const struct tcf_proto *tp,
                  const struct tcf_proto *orig_tp,
                  struct tcf_result *res,
                  bool compat_mode,
                  u32 *last_executed_chain)
 {
 #ifdef CONFIG_NET_CLS_ACT
     const int max_reclassify_loop = 16;
     const struct tcf_proto *first_tp;
     int limit = 0;
 
 reclassify:
 #endif
     for (; tp; tp = rcu_dereference_bh(tp->next)) {
         __be16 protocol = skb_protocol(skb, false);
         int err;
 
         if (tp->protocol != protocol &&
             tp->protocol != htons(ETH_P_ALL))
             continue;
 
         err = tp->classify(skb, tp, res);
 #ifdef CONFIG_NET_CLS_ACT
         if (unlikely(err == TC_ACT_RECLASSIFY && !compat_mode)) {
             first_tp = orig_tp;
             *last_executed_chain = first_tp->chain->index;
             goto reset;
         } else if (unlikely(TC_ACT_EXT_CMP(err, TC_ACT_GOTO_CHAIN))) {
             first_tp = res->goto_tp;
             *last_executed_chain = err & TC_ACT_EXT_VAL_MASK;
             goto reset;
         }
 #endif
         if (err >= 0)
             return err;
     }
 
     return TC_ACT_UNSPEC; /* signal: continue lookup */
 #ifdef CONFIG_NET_CLS_ACT
 reset:
     if (unlikely(limit++ >= max_reclassify_loop)) {
         net_notice_ratelimited("%u: reclassify loop, rule prio %u, protocol %02x\n",
                        tp->chain->block->index,
                        tp->prio & 0xffff,
                        ntohs(tp->protocol));
         return TC_ACT_SHOT;
     }
 
     tp = first_tp;
     goto reclassify;
 #endif
 }
 
 int tcf_classify(struct sk_buff *skb,
          const struct tcf_block *block,
          const struct tcf_proto *tp,
          struct tcf_result *res, bool compat_mode)
 {
 #if !IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
     u32 last_executed_chain = 0;
 
     return __tcf_classify(skb, tp, tp, res, compat_mode,
                   &last_executed_chain);
 #else
     u32 last_executed_chain = tp ? tp->chain->index : 0;
     const struct tcf_proto *orig_tp = tp;
     struct tc_skb_ext *ext;
     int ret;
 
     if (block) {
         ext = skb_ext_find(skb, TC_SKB_EXT);
 
         if (ext && ext->chain) {
             struct tcf_chain *fchain;
 
             fchain = tcf_chain_lookup_rcu(block, ext->chain);
             if (!fchain)
                 return TC_ACT_SHOT;
 
             /* Consume, so cloned/redirect skbs won't inherit ext */
             skb_ext_del(skb, TC_SKB_EXT);
 
             tp = rcu_dereference_bh(fchain->filter_chain);
             last_executed_chain = fchain->index;
         }
     }
 
     ret = __tcf_classify(skb, tp, orig_tp, res, compat_mode,
                  &last_executed_chain);
 
     if (tc_skb_ext_tc_enabled()) {
         /* If we missed on some chain */
         if (ret == TC_ACT_UNSPEC && last_executed_chain) {
             struct tc_skb_cb *cb = tc_skb_cb(skb);
 
             ext = tc_skb_ext_alloc(skb);
             if (WARN_ON_ONCE(!ext))
                 return TC_ACT_SHOT;
             ext->chain = last_executed_chain;
             ext->mru = cb->mru;
             ext->post_ct = cb->post_ct;
             ext->post_ct_snat = cb->post_ct_snat;
             ext->post_ct_dnat = cb->post_ct_dnat;
             ext->zone = cb->zone;
         }
     }
 
     return ret;
 #endif
 }
 EXPORT_SYMBOL(tcf_classify);
 
 struct tcf_chain_info {
     struct tcf_proto __rcu **pprev;
     struct tcf_proto __rcu *next;
 };
 
 static struct tcf_proto *tcf_chain_tp_prev(struct tcf_chain *chain,
                        struct tcf_chain_info *chain_info)
 {
     return tcf_chain_dereference(*chain_info->pprev, chain);
 }
 
 static int tcf_chain_tp_insert(struct tcf_chain *chain,
                    struct tcf_chain_info *chain_info,
                    struct tcf_proto *tp)
 {
     if (chain->flushing)
         return -EAGAIN;
 
     RCU_INIT_POINTER(tp->next, tcf_chain_tp_prev(chain, chain_info));
     if (*chain_info->pprev == chain->filter_chain)
         tcf_chain0_head_change(chain, tp);
     tcf_proto_get(tp);
     rcu_assign_pointer(*chain_info->pprev, tp);
 
     return 0;
 }
 
 static void tcf_chain_tp_remove(struct tcf_chain *chain,
                 struct tcf_chain_info *chain_info,
                 struct tcf_proto *tp)
 {
     struct tcf_proto *next = tcf_chain_dereference(chain_info->next, chain);
 
     tcf_proto_mark_delete(tp);
     if (tp == chain->filter_chain)
         tcf_chain0_head_change(chain, next);
     RCU_INIT_POINTER(*chain_info->pprev, next);
 }
 
 static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
                        struct tcf_chain_info *chain_info,
                        u32 protocol, u32 prio,
                        bool prio_allocate);
 
 /* Try to insert new proto.
  * If proto with specified priority already exists, free new proto
  * and return existing one.
  */
 
 static struct tcf_proto *tcf_chain_tp_insert_unique(struct tcf_chain *chain,
                             struct tcf_proto *tp_new,
                             u32 protocol, u32 prio,
                             bool rtnl_held)
 {
     struct tcf_chain_info chain_info;
     struct tcf_proto *tp;
     int err = 0;
 
     mutex_lock(&chain->filter_chain_lock);
 
     if (tcf_proto_exists_destroying(chain, tp_new)) {
         mutex_unlock(&chain->filter_chain_lock);
         tcf_proto_destroy(tp_new, rtnl_held, false, NULL);
         return ERR_PTR(-EAGAIN);
     }
 
     tp = tcf_chain_tp_find(chain, &chain_info,
                    protocol, prio, false);
     if (!tp)
         err = tcf_chain_tp_insert(chain, &chain_info, tp_new);
     mutex_unlock(&chain->filter_chain_lock);
 
     if (tp) {
         tcf_proto_destroy(tp_new, rtnl_held, false, NULL);
         tp_new = tp;
     } else if (err) {
         tcf_proto_destroy(tp_new, rtnl_held, false, NULL);
         tp_new = ERR_PTR(err);
     }
 
     return tp_new;
 }
 
 static void tcf_chain_tp_delete_empty(struct tcf_chain *chain,
                       struct tcf_proto *tp, bool rtnl_held,
                       struct netlink_ext_ack *extack)
 {
     struct tcf_chain_info chain_info;
     struct tcf_proto *tp_iter;
     struct tcf_proto **pprev;
     struct tcf_proto *next;
 
     mutex_lock(&chain->filter_chain_lock);
 
     /* Atomically find and remove tp from chain. */
     for (pprev = &chain->filter_chain;
          (tp_iter = tcf_chain_dereference(*pprev, chain));
          pprev = &tp_iter->next) {
         if (tp_iter == tp) {
             chain_info.pprev = pprev;
             chain_info.next = tp_iter->next;
             WARN_ON(tp_iter->deleting);
             break;
         }
     }
     /* Verify that tp still exists and no new filters were inserted
      * concurrently.
      * Mark tp for deletion if it is empty.
      */
     if (!tp_iter || !tcf_proto_check_delete(tp)) {
         mutex_unlock(&chain->filter_chain_lock);
         return;
     }
 
     tcf_proto_signal_destroying(chain, tp);
     next = tcf_chain_dereference(chain_info.next, chain);
     if (tp == chain->filter_chain)
         tcf_chain0_head_change(chain, next);
     RCU_INIT_POINTER(*chain_info.pprev, next);
     mutex_unlock(&chain->filter_chain_lock);
 
     tcf_proto_put(tp, rtnl_held, extack);
 }
 
 static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
                        struct tcf_chain_info *chain_info,
                        u32 protocol, u32 prio,
                        bool prio_allocate)
 {
     struct tcf_proto **pprev;
     struct tcf_proto *tp;
 
     /* Check the chain for existence of proto-tcf with this priority */
     for (pprev = &chain->filter_chain;
          (tp = tcf_chain_dereference(*pprev, chain));
          pprev = &tp->next) {
         if (tp->prio >= prio) {
             if (tp->prio == prio) {
                 if (prio_allocate ||
                     (tp->protocol != protocol && protocol))
                     return ERR_PTR(-EINVAL);
             } else {
                 tp = NULL;
             }
             break;
         }
     }
     chain_info->pprev = pprev;
     if (tp) {
         chain_info->next = tp->next;
         tcf_proto_get(tp);
     } else {
         chain_info->next = NULL;
     }
     return tp;
 }
 
 static int tcf_fill_node(struct net *net, struct sk_buff *skb,
              struct tcf_proto *tp, struct tcf_block *block,
              struct Qdisc *q, u32 parent, void *fh,
              u32 portid, u32 seq, u16 flags, int event,
              bool terse_dump, bool rtnl_held)
 {
     struct tcmsg *tcm;
     struct nlmsghdr  *nlh;
     unsigned char *b = skb_tail_pointer(skb);
 
     nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
     if (!nlh)
         goto out_nlmsg_trim;
     tcm = nlmsg_data(nlh);
     tcm->tcm_family = AF_UNSPEC;
     tcm->tcm__pad1 = 0;
     tcm->tcm__pad2 = 0;
     if (q) {
         tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
         tcm->tcm_parent = parent;
     } else {
         tcm->tcm_ifindex = TCM_IFINDEX_MAGIC_BLOCK;
         tcm->tcm_block_index = block->index;
     }
     tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
     if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
         goto nla_put_failure;
     if (nla_put_u32(skb, TCA_CHAIN, tp->chain->index))
         goto nla_put_failure;
     if (!fh) {
         tcm->tcm_handle = 0;
     } else if (terse_dump) {
         if (tp->ops->terse_dump) {
             if (tp->ops->terse_dump(net, tp, fh, skb, tcm,
                         rtnl_held) < 0)
                 goto nla_put_failure;
         } else {
             goto cls_op_not_supp;
         }
     } else {
         if (tp->ops->dump &&
             tp->ops->dump(net, tp, fh, skb, tcm, rtnl_held) < 0)
             goto nla_put_failure;
     }
     nlh->nlmsg_len = skb_tail_pointer(skb) - b;
     return skb->len;
 
 out_nlmsg_trim:
 nla_put_failure:
 cls_op_not_supp:
     nlmsg_trim(skb, b);
     return -1;
 }
 
 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
               struct nlmsghdr *n, struct tcf_proto *tp,
               struct tcf_block *block, struct Qdisc *q,
               u32 parent, void *fh, int event, bool unicast,
               bool rtnl_held)
 {
     struct sk_buff *skb;
     u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
     int err = 0;
 
     skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
     if (!skb)
         return -ENOBUFS;
 
     if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
               n->nlmsg_seq, n->nlmsg_flags, event,
               false, rtnl_held) <= 0) {
         kfree_skb(skb);
         return -EINVAL;
     }
 
     if (unicast)
         err = rtnl_unicast(skb, net, portid);
     else
         err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
                      n->nlmsg_flags & NLM_F_ECHO);
     return err;
 }
 
 static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
                   struct nlmsghdr *n, struct tcf_proto *tp,
                   struct tcf_block *block, struct Qdisc *q,
                   u32 parent, void *fh, bool unicast, bool *last,
                   bool rtnl_held, struct netlink_ext_ack *extack)
 {
     struct sk_buff *skb;
     u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
     int err;
 
     skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
     if (!skb)
         return -ENOBUFS;
 
     if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
               n->nlmsg_seq, n->nlmsg_flags, RTM_DELTFILTER,
               false, rtnl_held) <= 0) {
         NL_SET_ERR_MSG(extack, "Failed to build del event notification");
         kfree_skb(skb);
         return -EINVAL;
     }
 
     err = tp->ops->delete(tp, fh, last, rtnl_held, extack);
     if (err) {
         kfree_skb(skb);
         return err;
     }
 
     if (unicast)
         err = rtnl_unicast(skb, net, portid);
     else
         err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
                      n->nlmsg_flags & NLM_F_ECHO);
     if (err < 0)
         NL_SET_ERR_MSG(extack, "Failed to send filter delete notification");
 
     return err;
 }
 
 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
                  struct tcf_block *block, struct Qdisc *q,
                  u32 parent, struct nlmsghdr *n,
                  struct tcf_chain *chain, int event)
 {
     struct tcf_proto *tp;
 
     for (tp = tcf_get_next_proto(chain, NULL);
          tp; tp = tcf_get_next_proto(chain, tp))
         tfilter_notify(net, oskb, n, tp, block,
                    q, parent, NULL, event, false, true);
 }
 
 static void tfilter_put(struct tcf_proto *tp, void *fh)
 {
     if (tp->ops->put && fh)
         tp->ops->put(tp, fh);
 }
 
 static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
               struct netlink_ext_ack *extack)
 {
     struct net *net = sock_net(skb->sk);
     struct nlattr *tca[TCA_MAX + 1];
     char name[IFNAMSIZ];
     struct tcmsg *t;
     u32 protocol;
     u32 prio;
     bool prio_allocate;
     u32 parent;
     u32 chain_index;
     struct Qdisc *q;
     struct tcf_chain_info chain_info;
     struct tcf_chain *chain;
     struct tcf_block *block;
     struct tcf_proto *tp;
     unsigned long cl;
     void *fh;
     int err;
     int tp_created;
     bool rtnl_held = false;
     u32 flags;
 
     if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
         return -EPERM;
 
 replay:
     tp_created = 0;
 
     err = nlmsg_parse_deprecated(n, sizeof(*t), tca, TCA_MAX,
                      rtm_tca_policy, extack);
     if (err < 0)
         return err;
 
     t = nlmsg_data(n);
     protocol = TC_H_MIN(t->tcm_info);
     prio = TC_H_MAJ(t->tcm_info);
     prio_allocate = false;
     parent = t->tcm_parent;
     tp = NULL;
     cl = 0;
     block = NULL;
     q = NULL;
     chain = NULL;
     flags = 0;
 
     if (prio == 0) {
         /* If no priority is provided by the user,
          * we allocate one.
          */
         if (n->nlmsg_flags & NLM_F_CREATE) {
             prio = TC_H_MAKE(0x80000000U, 0U);
             prio_allocate = true;
         } else {
             NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");
             return -ENOENT;
         }
     }
 
     /* Find head of filter chain. */
 
     err = __tcf_qdisc_find(net, &q, &parent, t->tcm_ifindex, false, extack);
     if (err)
         return err;
 
     if (tcf_proto_check_kind(tca[TCA_KIND], name)) {
         NL_SET_ERR_MSG(extack, "Specified TC filter name too long");
         err = -EINVAL;
         goto errout;
     }
 
     /* Take rtnl mutex if rtnl_held was set to true on previous iteration,
      * block is shared (no qdisc found), qdisc is not unlocked, classifier
      * type is not specified, classifier is not unlocked.
      */
     if (rtnl_held ||
         (q && !(q->ops->cl_ops->flags & QDISC_CLASS_OPS_DOIT_UNLOCKED)) ||
         !tcf_proto_is_unlocked(name)) {
         rtnl_held = true;
         rtnl_lock();
     }
 
     err = __tcf_qdisc_cl_find(q, parent, &cl, t->tcm_ifindex, extack);
     if (err)
         goto errout;
 
     block = __tcf_block_find(net, q, cl, t->tcm_ifindex, t->tcm_block_index,
                  extack);
     if (IS_ERR(block)) {
         err = PTR_ERR(block);
         goto errout;
     }
     block->classid = parent;
 
     chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
     if (chain_index > TC_ACT_EXT_VAL_MASK) {
         NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
         err = -EINVAL;
         goto errout;
     }
     chain = tcf_chain_get(block, chain_index, true);
     if (!chain) {
         NL_SET_ERR_MSG(extack, "Cannot create specified filter chain");
         err = -ENOMEM;
         goto errout;
     }
 
     mutex_lock(&chain->filter_chain_lock);
     tp = tcf_chain_tp_find(chain, &chain_info, protocol,
                    prio, prio_allocate);
     if (IS_ERR(tp)) {
         NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
         err = PTR_ERR(tp);
         goto errout_locked;
     }
 
     if (tp == NULL) {
         struct tcf_proto *tp_new = NULL;
 
         if (chain->flushing) {
             err = -EAGAIN;
             goto errout_locked;
         }
 
         /* Proto-tcf does not exist, create new one */
 
         if (tca[TCA_KIND] == NULL || !protocol) {
             NL_SET_ERR_MSG(extack, "Filter kind and protocol must be specified");
             err = -EINVAL;
             goto errout_locked;
         }
 
         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
             NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
             err = -ENOENT;
             goto errout_locked;
         }
 
         if (prio_allocate)
             prio = tcf_auto_prio(tcf_chain_tp_prev(chain,
                                    &chain_info));
 
         mutex_unlock(&chain->filter_chain_lock);
         tp_new = tcf_proto_create(name, protocol, prio, chain,
                       rtnl_held, extack);
         if (IS_ERR(tp_new)) {
             err = PTR_ERR(tp_new);
             goto errout_tp;
         }
 
         tp_created = 1;
         tp = tcf_chain_tp_insert_unique(chain, tp_new, protocol, prio,
                         rtnl_held);
         if (IS_ERR(tp)) {
             err = PTR_ERR(tp);
             goto errout_tp;
         }
     } else {
         mutex_unlock(&chain->filter_chain_lock);
     }
 
     if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
         NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
         err = -EINVAL;
         goto errout;
     }
 
     fh = tp->ops->get(tp, t->tcm_handle);
 
     if (!fh) {
         if (!(n->nlmsg_flags & NLM_F_CREATE)) {
             NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
             err = -ENOENT;
             goto errout;
         }
     } else if (n->nlmsg_flags & NLM_F_EXCL) {
         tfilter_put(tp, fh);
         NL_SET_ERR_MSG(extack, "Filter already exists");
         err = -EEXIST;
         goto errout;
     }
 
     if (chain->tmplt_ops && chain->tmplt_ops != tp->ops) {
         tfilter_put(tp, fh);
         NL_SET_ERR_MSG(extack, "Chain template is set to a different filter kind");
         err = -EINVAL;
         goto errout;
     }
 
     if (!(n->nlmsg_flags & NLM_F_CREATE))
         flags |= TCA_ACT_FLAGS_REPLACE;
     if (!rtnl_held)
         flags |= TCA_ACT_FLAGS_NO_RTNL;
     err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
                   flags, extack);
     if (err == 0) {
         tfilter_notify(net, skb, n, tp, block, q, parent, fh,
                    RTM_NEWTFILTER, false, rtnl_held);
         tfilter_put(tp, fh);
         /* q pointer is NULL for shared blocks */
         if (q)
             q->flags &= ~TCQ_F_CAN_BYPASS;
     }
 
 errout:
     if (err && tp_created)
         tcf_chain_tp_delete_empty(chain, tp, rtnl_held, NULL);
 errout_tp:
     if (chain) {
         if (tp && !IS_ERR(tp))
             tcf_proto_put(tp, rtnl_held, NULL);
         if (!tp_created)
             tcf_chain_put(chain);
     }
     tcf_block_release(q, block, rtnl_held);
 
     if (rtnl_held)
         rtnl_unlock();
 
     if (err == -EAGAIN) {
         /* Take rtnl lock in case EAGAIN is caused by concurrent flush
          * of target chain.
          */
         rtnl_held = true;
         /* Replay the request. */
         goto replay;
     }
     return err;
 
 errout_locked:
     mutex_unlock(&chain->filter_chain_lock);
     goto errout;
 }
 
 static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
               struct netlink_ext_ack *extack)
 {
     struct net *net = sock_net(skb->sk);
     struct nlattr *tca[TCA_MAX + 1];
     char name[IFNAMSIZ];
     struct tcmsg *t;
     u32 protocol;
     u32 prio;
     u32 parent;
     u32 chain_index;
     struct Qdisc *q = NULL;
     struct tcf_chain_info chain_info;
     struct tcf_chain *chain = NULL;
     struct tcf_block *block = NULL;
     struct tcf_proto *tp = NULL;
     unsigned long cl = 0;
     void *fh = NULL;
     int err;
     bool rtnl_held = false;
 
     if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
         return -EPERM;
 
     err = nlmsg_parse_deprecated(n, sizeof(*t), tca, TCA_MAX,
                      rtm_tca_policy, extack);
     if (err < 0)
         return err;
 
     t = nlmsg_data(n);
     protocol = TC_H_MIN(t->tcm_info);
     prio = TC_H_MAJ(t->tcm_info);
     parent = t->tcm_parent;
 
     if (prio == 0 && (protocol || t->tcm_handle || tca[TCA_KIND])) {
         NL_SET_ERR_MSG(extack, "Cannot flush filters with protocol, handle or kind set");
         return -ENOENT;
     }
 
     /* Find head of filter chain. */
 
     err = __tcf_qdisc_find(net, &q, &parent, t->tcm_ifindex, false, extack);
     if (err)
         return err;
 
     if (tcf_proto_check_kind(tca[TCA_KIND], name)) {
         NL_SET_ERR_MSG(extack, "Specified TC filter name too long");
         err = -EINVAL;
         goto errout;
     }
     /* Take rtnl mutex if flushing whole chain, block is shared (no qdisc
      * found), qdisc is not unlocked, classifier type is not specified,
      * classifier is not unlocked.
      */
     if (!prio ||
         (q && !(q->ops->cl_ops->flags & QDISC_CLASS_OPS_DOIT_UNLOCKED)) ||
         !tcf_proto_is_unlocked(name)) {
         rtnl_held = true;
         rtnl_lock();
     }
 
     err = __tcf_qdisc_cl_find(q, parent, &cl, t->tcm_ifindex, extack);
     if (err)
         goto errout;
 
     block = __tcf_block_find(net, q, cl, t->tcm_ifindex, t->tcm_block_index,
                  extack);
     if (IS_ERR(block)) {
         err = PTR_ERR(block);
         goto errout;
     }
 
     chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
     if (chain_index > TC_ACT_EXT_VAL_MASK) {
         NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
         err = -EINVAL;
         goto errout;
     }
     chain = tcf_chain_get(block, chain_index, false);
     if (!chain) {
         /* User requested flush on non-existent chain. Nothing to do,
          * so just return success.
          */
         if (prio == 0) {
             err = 0;
             goto errout;
         }
         NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
         err = -ENOENT;
         goto errout;
     }
 
     if (prio == 0) {
         tfilter_notify_chain(net, skb, block, q, parent, n,
                      chain, RTM_DELTFILTER);
         tcf_chain_flush(chain, rtnl_held);
         err = 0;
         goto errout;
     }
 
     mutex_lock(&chain->filter_chain_lock);
     tp = tcf_chain_tp_find(chain, &chain_info, protocol,
                    prio, false);
     if (!tp || IS_ERR(tp)) {
         NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
         err = tp ? PTR_ERR(tp) : -ENOENT;
         goto errout_locked;
     } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
         NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
         err = -EINVAL;
         goto errout_locked;
     } else if (t->tcm_handle == 0) {
         tcf_proto_signal_destroying(chain, tp);
         tcf_chain_tp_remove(chain, &chain_info, tp);
         mutex_unlock(&chain->filter_chain_lock);
 
         tcf_proto_put(tp, rtnl_held, NULL);
         tfilter_notify(net, skb, n, tp, block, q, parent, fh,
                    RTM_DELTFILTER, false, rtnl_held);
         err = 0;
         goto errout;
     }
     mutex_unlock(&chain->filter_chain_lock);
 
     fh = tp->ops->get(tp, t->tcm_handle);
 
     if (!fh) {
         NL_SET_ERR_MSG(extack, "Specified filter handle not found");
         err = -ENOENT;
     } else {
         bool last;
 
         err = tfilter_del_notify(net, skb, n, tp, block,
                      q, parent, fh, false, &last,
                      rtnl_held, extack);
 
         if (err)
             goto errout;
         if (last)
             tcf_chain_tp_delete_empty(chain, tp, rtnl_held, extack);
     }
 
 errout:
     if (chain) {
         if (tp && !IS_ERR(tp))
             tcf_proto_put(tp, rtnl_held, NULL);
         tcf_chain_put(chain);
     }
     tcf_block_release(q, block, rtnl_held);
 
     if (rtnl_held)
         rtnl_unlock();
 
     return err;
 
 errout_locked:
     mutex_unlock(&chain->filter_chain_lock);
     goto errout;
 }
 
 static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
               struct netlink_ext_ack *extack)
 {
     struct net *net = sock_net(skb->sk);
     struct nlattr *tca[TCA_MAX + 1];
     char name[IFNAMSIZ];
     struct tcmsg *t;
     u32 protocol;
     u32 prio;
     u32 parent;
     u32 chain_index;
     struct Qdisc *q = NULL;
     struct tcf_chain_info chain_info;
     struct tcf_chain *chain = NULL;
     struct tcf_block *block = NULL;
     struct tcf_proto *tp = NULL;
     unsigned long cl = 0;
     void *fh = NULL;
     int err;
     bool rtnl_held = false;
 
     err = nlmsg_parse_deprecated(n, sizeof(*t), tca, TCA_MAX,
                      rtm_tca_policy, extack);
     if (err < 0)
         return err;
 
     t = nlmsg_data(n);
     protocol = TC_H_MIN(t->tcm_info);
     prio = TC_H_MAJ(t->tcm_info);
     parent = t->tcm_parent;
 
     if (prio == 0) {
         NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");
         return -ENOENT;
     }
 
     /* Find head of filter chain. */
 
     err = __tcf_qdisc_find(net, &q, &parent, t->tcm_ifindex, false, extack);
     if (err)
         return err;
 
     if (tcf_proto_check_kind(tca[TCA_KIND], name)) {
         NL_SET_ERR_MSG(extack, "Specified TC filter name too long");
         err = -EINVAL;
         goto errout;
     }
     /* Take rtnl mutex if block is shared (no qdisc found), qdisc is not
      * unlocked, classifier type is not specified, classifier is not
      * unlocked.
      */
     if ((q && !(q->ops->cl_ops->flags & QDISC_CLASS_OPS_DOIT_UNLOCKED)) ||
         !tcf_proto_is_unlocked(name)) {
         rtnl_held = true;
         rtnl_lock();
     }
 
     err = __tcf_qdisc_cl_find(q, parent, &cl, t->tcm_ifindex, extack);
     if (err)
         goto errout;
 
     block = __tcf_block_find(net, q, cl, t->tcm_ifindex, t->tcm_block_index,
                  extack);
     if (IS_ERR(block)) {
         err = PTR_ERR(block);
         goto errout;
     }
 
     chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
     if (chain_index > TC_ACT_EXT_VAL_MASK) {
         NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
         err = -EINVAL;
         goto errout;
     }
     chain = tcf_chain_get(block, chain_index, false);
     if (!chain) {
         NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
         err = -EINVAL;
         goto errout;
     }
 
     mutex_lock(&chain->filter_chain_lock);
     tp = tcf_chain_tp_find(chain, &chain_info, protocol,
                    prio, false);
     mutex_unlock(&chain->filter_chain_lock);
     if (!tp || IS_ERR(tp)) {
         NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
         err = tp ? PTR_ERR(tp) : -ENOENT;
         goto errout;
     } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
         NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
         err = -EINVAL;
         goto errout;
     }
 
     fh = tp->ops->get(tp, t->tcm_handle);
 
     if (!fh) {
         NL_SET_ERR_MSG(extack, "Specified filter handle not found");
         err = -ENOENT;
     } else {
         err = tfilter_notify(net, skb, n, tp, block, q, parent,
                      fh, RTM_NEWTFILTER, true, rtnl_held);
         if (err < 0)
             NL_SET_ERR_MSG(extack, "Failed to send filter notify message");
     }
 
     tfilter_put(tp, fh);
 errout:
     if (chain) {
         if (tp && !IS_ERR(tp))
             tcf_proto_put(tp, rtnl_held, NULL);
         tcf_chain_put(chain);
     }
     tcf_block_release(q, block, rtnl_held);
 
     if (rtnl_held)
         rtnl_unlock();
 
     return err;
 }
 
 struct tcf_dump_args {
     struct tcf_walker w;
     struct sk_buff *skb;
     struct netlink_callback *cb;
     struct tcf_block *block;
     struct Qdisc *q;
     u32 parent;
     bool terse_dump;
 };
 
 static int tcf_node_dump(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
 {
     struct tcf_dump_args *a = (void *)arg;
     struct net *net = sock_net(a->skb->sk);
 
     return tcf_fill_node(net, a->skb, tp, a->block, a->q, a->parent,
                  n, NETLINK_CB(a->cb->skb).portid,
                  a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
                  RTM_NEWTFILTER, a->terse_dump, true);
 }
 
 static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
                struct sk_buff *skb, struct netlink_callback *cb,
                long index_start, long *p_index, bool terse)
 {
     struct net *net = sock_net(skb->sk);
     struct tcf_block *block = chain->block;
     struct tcmsg *tcm = nlmsg_data(cb->nlh);
     struct tcf_proto *tp, *tp_prev;
     struct tcf_dump_args arg;
 
     for (tp = __tcf_get_next_proto(chain, NULL);
          tp;
          tp_prev = tp,
              tp = __tcf_get_next_proto(chain, tp),
              tcf_proto_put(tp_prev, true, NULL),
              (*p_index)++) {
         if (*p_index < index_start)
             continue;
         if (TC_H_MAJ(tcm->tcm_info) &&
             TC_H_MAJ(tcm->tcm_info) != tp->prio)
             continue;
         if (TC_H_MIN(tcm->tcm_info) &&
             TC_H_MIN(tcm->tcm_info) != tp->protocol)
             continue;
         if (*p_index > index_start)
             memset(&cb->args[1], 0,
                    sizeof(cb->args) - sizeof(cb->args[0]));
         if (cb->args[1] == 0) {
             if (tcf_fill_node(net, skb, tp, block, q, parent, NULL,
                       NETLINK_CB(cb->skb).portid,
                       cb->nlh->nlmsg_seq, NLM_F_MULTI,
                       RTM_NEWTFILTER, false, true) <= 0)
                 goto errout;
             cb->args[1] = 1;
         }
         if (!tp->ops->walk)
             continue;
         arg.w.fn = tcf_node_dump;
         arg.skb = skb;
         arg.cb = cb;
         arg.block = block;
         arg.q = q;
         arg.parent = parent;
         arg.w.stop = 0;
         arg.w.skip = cb->args[1] - 1;
         arg.w.count = 0;
         arg.w.cookie = cb->args[2];
         arg.terse_dump = terse;
         tp->ops->walk(tp, &arg.w, true);
         cb->args[2] = arg.w.cookie;
         cb->args[1] = arg.w.count + 1;
         if (arg.w.stop)
             goto errout;
     }
     return true;
 
 errout:
     tcf_proto_put(tp, true, NULL);
     return false;
 }
 
 static const struct nla_policy tcf_tfilter_dump_policy[TCA_MAX + 1] = {
     [TCA_DUMP_FLAGS] = NLA_POLICY_BITFIELD32(TCA_DUMP_FLAGS_TERSE),
 };
 
 /* called with RTNL */
 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct tcf_chain *chain, *chain_prev;
     struct net *net = sock_net(skb->sk);
     struct nlattr *tca[TCA_MAX + 1];
     struct Qdisc *q = NULL;
     struct tcf_block *block;
     struct tcmsg *tcm = nlmsg_data(cb->nlh);
     bool terse_dump = false;
     long index_start;
     long index;
     u32 parent;
     int err;
 
     if (nlmsg_len(cb->nlh) < sizeof(*tcm))
         return skb->len;
 
     err = nlmsg_parse_deprecated(cb->nlh, sizeof(*tcm), tca, TCA_MAX,
                      tcf_tfilter_dump_policy, cb->extack);
     if (err)
         return err;
 
     if (tca[TCA_DUMP_FLAGS]) {
         struct nla_bitfield32 flags =
             nla_get_bitfield32(tca[TCA_DUMP_FLAGS]);
 
         terse_dump = flags.value & TCA_DUMP_FLAGS_TERSE;
     }
 
     if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
         block = tcf_block_refcnt_get(net, tcm->tcm_block_index);
         if (!block)
             goto out;
         /* If we work with block index, q is NULL and parent value
          * will never be used in the following code. The check
          * in tcf_fill_node prevents it. However, compiler does not
          * see that far, so set parent to zero to silence the warning
          * about parent being uninitialized.
          */
         parent = 0;
     } else {
         const struct Qdisc_class_ops *cops;
         struct net_device *dev;
         unsigned long cl = 0;
 
         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
         if (!dev)
             return skb->len;
 
         parent = tcm->tcm_parent;
         if (!parent)
             q = rtnl_dereference(dev->qdisc);
         else
             q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
         if (!q)
             goto out;
         cops = q->ops->cl_ops;
         if (!cops)
             goto out;
         if (!cops->tcf_block)
             goto out;
         if (TC_H_MIN(tcm->tcm_parent)) {
             cl = cops->find(q, tcm->tcm_parent);
             if (cl == 0)
                 goto out;
         }
         block = cops->tcf_block(q, cl, NULL);
         if (!block)
             goto out;
         parent = block->classid;
         if (tcf_block_shared(block))
             q = NULL;
     }
 
     index_start = cb->args[0];
     index = 0;
 
     for (chain = __tcf_get_next_chain(block, NULL);
          chain;
          chain_prev = chain,
              chain = __tcf_get_next_chain(block, chain),
              tcf_chain_put(chain_prev)) {
         if (tca[TCA_CHAIN] &&
             nla_get_u32(tca[TCA_CHAIN]) != chain->index)
             continue;
         if (!tcf_chain_dump(chain, q, parent, skb, cb,
                     index_start, &index, terse_dump)) {
             tcf_chain_put(chain);
             err = -EMSGSIZE;
             break;
         }
     }
 
     if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK)
         tcf_block_refcnt_put(block, true);
     cb->args[0] = index;
 
 out:
     /* If we did no progress, the error (EMSGSIZE) is real */
     if (skb->len == 0 && err)
         return err;
     return skb->len;
 }
 
 static int tc_chain_fill_node(const struct tcf_proto_ops *tmplt_ops,
                   void *tmplt_priv, u32 chain_index,
                   struct net *net, struct sk_buff *skb,
                   struct tcf_block *block,
                   u32 portid, u32 seq, u16 flags, int event)
 {
     unsigned char *b = skb_tail_pointer(skb);
     const struct tcf_proto_ops *ops;
     struct nlmsghdr *nlh;
     struct tcmsg *tcm;
     void *priv;
 
     ops = tmplt_ops;
     priv = tmplt_priv;
 
     nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
     if (!nlh)
         goto out_nlmsg_trim;
     tcm = nlmsg_data(nlh);
     tcm->tcm_family = AF_UNSPEC;
     tcm->tcm__pad1 = 0;
     tcm->tcm__pad2 = 0;
     tcm->tcm_handle = 0;
     if (block->q) {
         tcm->tcm_ifindex = qdisc_dev(block->q)->ifindex;
         tcm->tcm_parent = block->q->handle;
     } else {
         tcm->tcm_ifindex = TCM_IFINDEX_MAGIC_BLOCK;
         tcm->tcm_block_index = block->index;
     }
 
     if (nla_put_u32(skb, TCA_CHAIN, chain_index))
         goto nla_put_failure;
 
     if (ops) {
         if (nla_put_string(skb, TCA_KIND, ops->kind))
             goto nla_put_failure;
         if (ops->tmplt_dump(skb, net, priv) < 0)
             goto nla_put_failure;
     }
 
     nlh->nlmsg_len = skb_tail_pointer(skb) - b;
     return skb->len;
 
 out_nlmsg_trim:
 nla_put_failure:
     nlmsg_trim(skb, b);
     return -EMSGSIZE;
 }
 
 static int tc_chain_notify(struct tcf_chain *chain, struct sk_buff *oskb,
                u32 seq, u16 flags, int event, bool unicast)
 {
     u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
     struct tcf_block *block = chain->block;
     struct net *net = block->net;
     struct sk_buff *skb;
     int err = 0;
 
     skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
     if (!skb)
         return -ENOBUFS;
 
     if (tc_chain_fill_node(chain->tmplt_ops, chain->tmplt_priv,
                    chain->index, net, skb, block, portid,
                    seq, flags, event) <= 0) {
         kfree_skb(skb);
         return -EINVAL;
     }
 
     if (unicast)
         err = rtnl_unicast(skb, net, portid);
     else
         err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
                      flags & NLM_F_ECHO);
 
     return err;
 }
 
 static int tc_chain_notify_delete(const struct tcf_proto_ops *tmplt_ops,
                   void *tmplt_priv, u32 chain_index,
                   struct tcf_block *block, struct sk_buff *oskb,
                   u32 seq, u16 flags, bool unicast)
 {
     u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
     struct net *net = block->net;
     struct sk_buff *skb;
 
     skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
     if (!skb)
         return -ENOBUFS;
 
     if (tc_chain_fill_node(tmplt_ops, tmplt_priv, chain_index, net, skb,
                    block, portid, seq, flags, RTM_DELCHAIN) <= 0) {
         kfree_skb(skb);
         return -EINVAL;
     }
 
     if (unicast)
         return rtnl_unicast(skb, net, portid);
 
     return rtnetlink_send(skb, net, portid, RTNLGRP_TC, flags & NLM_F_ECHO);
 }
 
 static int tc_chain_tmplt_add(struct tcf_chain *chain, struct net *net,
                   struct nlattr **tca,
                   struct netlink_ext_ack *extack)
 {
     const struct tcf_proto_ops *ops;
     char name[IFNAMSIZ];
     void *tmplt_priv;
 
     /* If kind is not set, user did not specify template. */
     if (!tca[TCA_KIND])
         return 0;
 
     if (tcf_proto_check_kind(tca[TCA_KIND], name)) {
         NL_SET_ERR_MSG(extack, "Specified TC chain template name too long");
         return -EINVAL;
     }
 
     ops = tcf_proto_lookup_ops(name, true, extack);
     if (IS_ERR(ops))
         return PTR_ERR(ops);
     if (!ops->tmplt_create || !ops->tmplt_destroy || !ops->tmplt_dump) {
         NL_SET_ERR_MSG(extack, "Chain templates are not supported with specified classifier");
         return -EOPNOTSUPP;
     }
 
     tmplt_priv = ops->tmplt_create(net, chain, tca, extack);
     if (IS_ERR(tmplt_priv)) {
         module_put(ops->owner);
         return PTR_ERR(tmplt_priv);
     }
     chain->tmplt_ops = ops;
     chain->tmplt_priv = tmplt_priv;
     return 0;
 }
 
 static void tc_chain_tmplt_del(const struct tcf_proto_ops *tmplt_ops,
                    void *tmplt_priv)
 {
     /* If template ops are set, no work to do for us. */
     if (!tmplt_ops)
         return;
 
     tmplt_ops->tmplt_destroy(tmplt_priv);
     module_put(tmplt_ops->owner);
 }
 
 /* Add/delete/get a chain */
 
 static int tc_ctl_chain(struct sk_buff *skb, struct nlmsghdr *n,
             struct netlink_ext_ack *extack)
 {
     struct net *net = sock_net(skb->sk);
     struct nlattr *tca[TCA_MAX + 1];
     struct tcmsg *t;
     u32 parent;
     u32 chain_index;
     struct Qdisc *q;
     struct tcf_chain *chain;
     struct tcf_block *block;
     unsigned long cl;
     int err;
 
     if (n->nlmsg_type != RTM_GETCHAIN &&
         !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
         return -EPERM;
 
 replay:
     q = NULL;
     err = nlmsg_parse_deprecated(n, sizeof(*t), tca, TCA_MAX,
                      rtm_tca_policy, extack);
     if (err < 0)
         return err;
 
     t = nlmsg_data(n);
     parent = t->tcm_parent;
     cl = 0;
 
     block = tcf_block_find(net, &q, &parent, &cl,
                    t->tcm_ifindex, t->tcm_block_index, extack);
     if (IS_ERR(block))
         return PTR_ERR(block);
 
     chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
     if (chain_index > TC_ACT_EXT_VAL_MASK) {
         NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
         err = -EINVAL;
         goto errout_block;
     }
 
     mutex_lock(&block->lock);
     chain = tcf_chain_lookup(block, chain_index);
     if (n->nlmsg_type == RTM_NEWCHAIN) {
         if (chain) {
             if (tcf_chain_held_by_acts_only(chain)) {
                 /* The chain exists only because there is
                  * some action referencing it.
                  */
                 tcf_chain_hold(chain);
             } else {
                 NL_SET_ERR_MSG(extack, "Filter chain already exists");
                 err = -EEXIST;
                 goto errout_block_locked;
             }
         } else {
             if (!(n->nlmsg_flags & NLM_F_CREATE)) {
                 NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain");
                 err = -ENOENT;
                 goto errout_block_locked;
             }
             chain = tcf_chain_create(block, chain_index);
             if (!chain) {
                 NL_SET_ERR_MSG(extack, "Failed to create filter chain");
                 err = -ENOMEM;
                 goto errout_block_locked;
             }
         }
     } else {
         if (!chain || tcf_chain_held_by_acts_only(chain)) {
             NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
             err = -EINVAL;
             goto errout_block_locked;
         }
         tcf_chain_hold(chain);
     }
 
     if (n->nlmsg_type == RTM_NEWCHAIN) {
         /* Modifying chain requires holding parent block lock. In case
          * the chain was successfully added, take a reference to the
          * chain. This ensures that an empty chain does not disappear at
          * the end of this function.
          */
         tcf_chain_hold(chain);
         chain->explicitly_created = true;
     }
     mutex_unlock(&block->lock);
 
     switch (n->nlmsg_type) {
     case RTM_NEWCHAIN:
         err = tc_chain_tmplt_add(chain, net, tca, extack);
         if (err) {
             tcf_chain_put_explicitly_created(chain);
             goto errout;
         }
 
         tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
                 RTM_NEWCHAIN, false);
         break;
     case RTM_DELCHAIN:
         tfilter_notify_chain(net, skb, block, q, parent, n,
                      chain, RTM_DELTFILTER);
         /* Flush the chain first as the user requested chain removal. */
         tcf_chain_flush(chain, true);
         /* In case the chain was successfully deleted, put a reference
          * to the chain previously taken during addition.
          */
         tcf_chain_put_explicitly_created(chain);
         break;
     case RTM_GETCHAIN:
         err = tc_chain_notify(chain, skb, n->nlmsg_seq,
                       n->nlmsg_flags, n->nlmsg_type, true);
         if (err < 0)
             NL_SET_ERR_MSG(extack, "Failed to send chain notify message");
         break;
     default:
         err = -EOPNOTSUPP;
         NL_SET_ERR_MSG(extack, "Unsupported message type");
         goto errout;
     }
 
 errout:
     tcf_chain_put(chain);
 errout_block:
     tcf_block_release(q, block, true);
     if (err == -EAGAIN)
         /* Replay the request. */
         goto replay;
     return err;
 
 errout_block_locked:
     mutex_unlock(&block->lock);
     goto errout_block;
 }
 
 /* called with RTNL */
 static int tc_dump_chain(struct sk_buff *skb, struct netlink_callback *cb)
 {
     struct net *net = sock_net(skb->sk);
     struct nlattr *tca[TCA_MAX + 1];
     struct Qdisc *q = NULL;
     struct tcf_block *block;
     struct tcmsg *tcm = nlmsg_data(cb->nlh);
     struct tcf_chain *chain;
     long index_start;
     long index;
     int err;
 
     if (nlmsg_len(cb->nlh) < sizeof(*tcm))
         return skb->len;
 
     err = nlmsg_parse_deprecated(cb->nlh, sizeof(*tcm), tca, TCA_MAX,
                      rtm_tca_policy, cb->extack);
     if (err)
         return err;
 
     if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
         block = tcf_block_refcnt_get(net, tcm->tcm_block_index);
         if (!block)
             goto out;
     } else {
         const struct Qdisc_class_ops *cops;
         struct net_device *dev;
         unsigned long cl = 0;
 
         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
         if (!dev)
             return skb->len;
 
         if (!tcm->tcm_parent)
             q = rtnl_dereference(dev->qdisc);
         else
             q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 
         if (!q)
             goto out;
         cops = q->ops->cl_ops;
         if (!cops)
             goto out;
         if (!cops->tcf_block)
             goto out;
         if (TC_H_MIN(tcm->tcm_parent)) {
             cl = cops->find(q, tcm->tcm_parent);
             if (cl == 0)
                 goto out;
         }
         block = cops->tcf_block(q, cl, NULL);
         if (!block)
             goto out;
         if (tcf_block_shared(block))
             q = NULL;
     }
 
     index_start = cb->args[0];
     index = 0;
 
     mutex_lock(&block->lock);
     list_for_each_entry(chain, &block->chain_list, list) {
         if ((tca[TCA_CHAIN] &&
              nla_get_u32(tca[TCA_CHAIN]) != chain->index))
             continue;
         if (index < index_start) {
             index++;
             continue;
         }
         if (tcf_chain_held_by_acts_only(chain))
             continue;
         err = tc_chain_fill_node(chain->tmplt_ops, chain->tmplt_priv,
                      chain->index, net, skb, block,
                      NETLINK_CB(cb->skb).portid,
                      cb->nlh->nlmsg_seq, NLM_F_MULTI,
                      RTM_NEWCHAIN);
         if (err <= 0)
             break;
         index++;
     }
     mutex_unlock(&block->lock);
 
     if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK)
         tcf_block_refcnt_put(block, true);
     cb->args[0] = index;
 
 out:
     /* If we did no progress, the error (EMSGSIZE) is real */
     if (skb->len == 0 && err)
         return err;
     return skb->len;
 }
 
 void tcf_exts_destroy(struct tcf_exts *exts)
 {
 #ifdef CONFIG_NET_CLS_ACT
     if (exts->actions) {
         tcf_action_destroy(exts->actions, TCA_ACT_UNBIND);
         kfree(exts->actions);
     }
     exts->nr_actions = 0;
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_destroy);
 
 int tcf_exts_validate_ex(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
              struct nlattr *rate_tlv, struct tcf_exts *exts,
              u32 flags, u32 fl_flags, struct netlink_ext_ack *extack)
 {
 #ifdef CONFIG_NET_CLS_ACT
     {
         int init_res[TCA_ACT_MAX_PRIO] = {};
         struct tc_action *act;
         size_t attr_size = 0;
 
         if (exts->police && tb[exts->police]) {
             struct tc_action_ops *a_o;
 
             a_o = tc_action_load_ops(tb[exts->police], true,
                          !(flags & TCA_ACT_FLAGS_NO_RTNL),
                          extack);
             if (IS_ERR(a_o))
                 return PTR_ERR(a_o);
             flags |= TCA_ACT_FLAGS_POLICE | TCA_ACT_FLAGS_BIND;
             act = tcf_action_init_1(net, tp, tb[exts->police],
                         rate_tlv, a_o, init_res, flags,
                         extack);
             module_put(a_o->owner);
             if (IS_ERR(act))
                 return PTR_ERR(act);
 
             act->type = exts->type = TCA_OLD_COMPAT;
             exts->actions[0] = act;
             exts->nr_actions = 1;
             tcf_idr_insert_many(exts->actions);
         } else if (exts->action && tb[exts->action]) {
             int err;
 
             flags |= TCA_ACT_FLAGS_BIND;
             err = tcf_action_init(net, tp, tb[exts->action],
                           rate_tlv, exts->actions, init_res,
                           &attr_size, flags, fl_flags,
                           extack);
             if (err < 0)
                 return err;
             exts->nr_actions = err;
         }
     }
 #else
     if ((exts->action && tb[exts->action]) ||
         (exts->police && tb[exts->police])) {
         NL_SET_ERR_MSG(extack, "Classifier actions are not supported per compile options (CONFIG_NET_CLS_ACT)");
         return -EOPNOTSUPP;
     }
 #endif
 
     return 0;
 }
 EXPORT_SYMBOL(tcf_exts_validate_ex);
 
 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
               struct nlattr *rate_tlv, struct tcf_exts *exts,
               u32 flags, struct netlink_ext_ack *extack)
 {
     return tcf_exts_validate_ex(net, tp, tb, rate_tlv, exts,
                     flags, 0, extack);
 }
 EXPORT_SYMBOL(tcf_exts_validate);
 
 void tcf_exts_change(struct tcf_exts *dst, struct tcf_exts *src)
 {
 #ifdef CONFIG_NET_CLS_ACT
     struct tcf_exts old = *dst;
 
     *dst = *src;
     tcf_exts_destroy(&old);
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_change);
 
 #ifdef CONFIG_NET_CLS_ACT
 static struct tc_action *tcf_exts_first_act(struct tcf_exts *exts)
 {
     if (exts->nr_actions == 0)
         return NULL;
     else
         return exts->actions[0];
 }
 #endif
 
 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 {
 #ifdef CONFIG_NET_CLS_ACT
     struct nlattr *nest;
 
     if (exts->action && tcf_exts_has_actions(exts)) {
         /*
          * again for backward compatible mode - we want
          * to work with both old and new modes of entering
          * tc data even if iproute2  was newer - jhs
          */
         if (exts->type != TCA_OLD_COMPAT) {
             nest = nla_nest_start_noflag(skb, exts->action);
             if (nest == NULL)
                 goto nla_put_failure;
 
             if (tcf_action_dump(skb, exts->actions, 0, 0, false)
                 < 0)
                 goto nla_put_failure;
             nla_nest_end(skb, nest);
         } else if (exts->police) {
             struct tc_action *act = tcf_exts_first_act(exts);
             nest = nla_nest_start_noflag(skb, exts->police);
             if (nest == NULL || !act)
                 goto nla_put_failure;
             if (tcf_action_dump_old(skb, act, 0, 0) < 0)
                 goto nla_put_failure;
             nla_nest_end(skb, nest);
         }
     }
     return 0;
 
 nla_put_failure:
     nla_nest_cancel(skb, nest);
     return -1;
 #else
     return 0;
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_dump);
 
 int tcf_exts_terse_dump(struct sk_buff *skb, struct tcf_exts *exts)
 {
 #ifdef CONFIG_NET_CLS_ACT
     struct nlattr *nest;
 
     if (!exts->action || !tcf_exts_has_actions(exts))
         return 0;
 
     nest = nla_nest_start_noflag(skb, exts->action);
     if (!nest)
         goto nla_put_failure;
 
     if (tcf_action_dump(skb, exts->actions, 0, 0, true) < 0)
         goto nla_put_failure;
     nla_nest_end(skb, nest);
     return 0;
 
 nla_put_failure:
     nla_nest_cancel(skb, nest);
     return -1;
 #else
     return 0;
 #endif
 }
 EXPORT_SYMBOL(tcf_exts_terse_dump);
 
 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
 {
 #ifdef CONFIG_NET_CLS_ACT
     struct tc_action *a = tcf_exts_first_act(exts);
     if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
         return -1;
 #endif
     return 0;
 }
 EXPORT_SYMBOL(tcf_exts_dump_stats);
 
 static void tcf_block_offload_inc(struct tcf_block *block, u32 *flags)
 {
     if (*flags & TCA_CLS_FLAGS_IN_HW)
         return;
     *flags |= TCA_CLS_FLAGS_IN_HW;
     atomic_inc(&block->offloadcnt);
 }
 
 static void tcf_block_offload_dec(struct tcf_block *block, u32 *flags)
 {
     if (!(*flags & TCA_CLS_FLAGS_IN_HW))
         return;
     *flags &= ~TCA_CLS_FLAGS_IN_HW;
     atomic_dec(&block->offloadcnt);
 }
 
 static void tc_cls_offload_cnt_update(struct tcf_block *block,
                       struct tcf_proto *tp, u32 *cnt,
                       u32 *flags, u32 diff, bool add)
 {
     lockdep_assert_held(&block->cb_lock);
 
     spin_lock(&tp->lock);
     if (add) {
         if (!*cnt)
             tcf_block_offload_inc(block, flags);
         *cnt += diff;
     } else {
         *cnt -= diff;
         if (!*cnt)
             tcf_block_offload_dec(block, flags);
     }
     spin_unlock(&tp->lock);
 }
 
 static void
 tc_cls_offload_cnt_reset(struct tcf_block *block, struct tcf_proto *tp,
              u32 *cnt, u32 *flags)
 {
     lockdep_assert_held(&block->cb_lock);
 
     spin_lock(&tp->lock);
     tcf_block_offload_dec(block, flags);
     *cnt = 0;
     spin_unlock(&tp->lock);
 }
 
 static int
 __tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type,
            void *type_data, bool err_stop)
 {
     struct flow_block_cb *block_cb;
     int ok_count = 0;
     int err;
 
     list_for_each_entry(block_cb, &block->flow_block.cb_list, list) {
         err = block_cb->cb(type, type_data, block_cb->cb_priv);
         if (err) {
             if (err_stop)
                 return err;
         } else {
             ok_count++;
         }
     }
     return ok_count;
 }
 
 int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type,
              void *type_data, bool err_stop, bool rtnl_held)
 {
     bool take_rtnl = READ_ONCE(block->lockeddevcnt) && !rtnl_held;
     int ok_count;
 
 retry:
     if (take_rtnl)
         rtnl_lock();
     down_read(&block->cb_lock);
     /* Need to obtain rtnl lock if block is bound to devs that require it.
      * In block bind code cb_lock is obtained while holding rtnl, so we must
      * obtain the locks in same order here.
      */
     if (!rtnl_held && !take_rtnl && block->lockeddevcnt) {
         up_read(&block->cb_lock);
         take_rtnl = true;
         goto retry;
     }
 
     ok_count = __tc_setup_cb_call(block, type, type_data, err_stop);
 
     up_read(&block->cb_lock);
     if (take_rtnl)
         rtnl_unlock();
     return ok_count;
 }
 EXPORT_SYMBOL(tc_setup_cb_call);
 
 /* Non-destructive filter add. If filter that wasn't already in hardware is
  * successfully offloaded, increment block offloads counter. On failure,
  * previously offloaded filter is considered to be intact and offloads counter
  * is not decremented.
  */
 
 int tc_setup_cb_add(struct tcf_block *block, struct tcf_proto *tp,
             enum tc_setup_type type, void *type_data, bool err_stop,
             u32 *flags, unsigned int *in_hw_count, bool rtnl_held)
 {
     bool take_rtnl = READ_ONCE(block->lockeddevcnt) && !rtnl_held;
     int ok_count;
 
 retry:
     if (take_rtnl)
         rtnl_lock();
     down_read(&block->cb_lock);
     /* Need to obtain rtnl lock if block is bound to devs that require it.
      * In block bind code cb_lock is obtained while holding rtnl, so we must
      * obtain the locks in same order here.
      */
     if (!rtnl_held && !take_rtnl && block->lockeddevcnt) {
         up_read(&block->cb_lock);
         take_rtnl = true;
         goto retry;
     }
 
     /* Make sure all netdevs sharing this block are offload-capable. */
     if (block->nooffloaddevcnt && err_stop) {
         ok_count = -EOPNOTSUPP;
         goto err_unlock;
     }
 
     ok_count = __tc_setup_cb_call(block, type, type_data, err_stop);
     if (ok_count < 0)
         goto err_unlock;
 
     if (tp->ops->hw_add)
         tp->ops->hw_add(tp, type_data);
     if (ok_count > 0)
         tc_cls_offload_cnt_update(block, tp, in_hw_count, flags,
                       ok_count, true);
 err_unlock:
     up_read(&block->cb_lock);
     if (take_rtnl)
         rtnl_unlock();
     return min(ok_count, 0);
 }
 EXPORT_SYMBOL(tc_setup_cb_add);
 
 /* Destructive filter replace. If filter that wasn't already in hardware is
  * successfully offloaded, increment block offload counter. On failure,
  * previously offloaded filter is considered to be destroyed and offload counter
  * is decremented.
  */
 
 int tc_setup_cb_replace(struct tcf_block *block, struct tcf_proto *tp,
             enum tc_setup_type type, void *type_data, bool err_stop,
             u32 *old_flags, unsigned int *old_in_hw_count,
             u32 *new_flags, unsigned int *new_in_hw_count,
             bool rtnl_held)
 {
     bool take_rtnl = READ_ONCE(block->lockeddevcnt) && !rtnl_held;
     int ok_count;
 
 retry:
     if (take_rtnl)
         rtnl_lock();
     down_read(&block->cb_lock);
     /* Need to obtain rtnl lock if block is bound to devs that require it.
      * In block bind code cb_lock is obtained while holding rtnl, so we must
      * obtain the locks in same order here.
      */
     if (!rtnl_held && !take_rtnl && block->lockeddevcnt) {
         up_read(&block->cb_lock);
         take_rtnl = true;
         goto retry;
     }
 
     /* Make sure all netdevs sharing this block are offload-capable. */
     if (block->nooffloaddevcnt && err_stop) {
         ok_count = -EOPNOTSUPP;
         goto err_unlock;
     }
 
     tc_cls_offload_cnt_reset(block, tp, old_in_hw_count, old_flags);
     if (tp->ops->hw_del)
         tp->ops->hw_del(tp, type_data);
 
     ok_count = __tc_setup_cb_call(block, type, type_data, err_stop);
     if (ok_count < 0)
         goto err_unlock;
 
     if (tp->ops->hw_add)
         tp->ops->hw_add(tp, type_data);
     if (ok_count > 0)
         tc_cls_offload_cnt_update(block, tp, new_in_hw_count,
                       new_flags, ok_count, true);
 err_unlock:
     up_read(&block->cb_lock);
     if (take_rtnl)
         rtnl_unlock();
     return min(ok_count, 0);
 }
 EXPORT_SYMBOL(tc_setup_cb_replace);
 
 /* Destroy filter and decrement block offload counter, if filter was previously
  * offloaded.
  */
 
 int tc_setup_cb_destroy(struct tcf_block *block, struct tcf_proto *tp,
             enum tc_setup_type type, void *type_data, bool err_stop,
             u32 *flags, unsigned int *in_hw_count, bool rtnl_held)
 {
     bool take_rtnl = READ_ONCE(block->lockeddevcnt) && !rtnl_held;
     int ok_count;
 
 retry:
     if (take_rtnl)
         rtnl_lock();
     down_read(&block->cb_lock);
     /* Need to obtain rtnl lock if block is bound to devs that require it.
      * In block bind code cb_lock is obtained while holding rtnl, so we must
      * obtain the locks in same order here.
      */
     if (!rtnl_held && !take_rtnl && block->lockeddevcnt) {
         up_read(&block->cb_lock);
         take_rtnl = true;
         goto retry;
     }
 
     ok_count = __tc_setup_cb_call(block, type, type_data, err_stop);
 
     tc_cls_offload_cnt_reset(block, tp, in_hw_count, flags);
     if (tp->ops->hw_del)
         tp->ops->hw_del(tp, type_data);
 
     up_read(&block->cb_lock);
     if (take_rtnl)
         rtnl_unlock();
     return min(ok_count, 0);
 }
 EXPORT_SYMBOL(tc_setup_cb_destroy);
 
 int tc_setup_cb_reoffload(struct tcf_block *block, struct tcf_proto *tp,
               bool add, flow_setup_cb_t *cb,
               enum tc_setup_type type, void *type_data,
               void *cb_priv, u32 *flags, unsigned int *in_hw_count)
 {
     int err = cb(type, type_data, cb_priv);
 
     if (err) {
         if (add && tc_skip_sw(*flags))
             return err;
     } else {
         tc_cls_offload_cnt_update(block, tp, in_hw_count, flags, 1,
                       add);
     }
 
     return 0;
 }
 EXPORT_SYMBOL(tc_setup_cb_reoffload);
 
 static int tcf_act_get_cookie(struct flow_action_entry *entry,
                   const struct tc_action *act)
 {
     struct tc_cookie *cookie;
     int err = 0;
 
     rcu_read_lock();
     cookie = rcu_dereference(act->act_cookie);
     if (cookie) {
         entry->cookie = flow_action_cookie_create(cookie->data,
                               cookie->len,
                               GFP_ATOMIC);
         if (!entry->cookie)
             err = -ENOMEM;
     }
     rcu_read_unlock();
     return err;
 }
 
 static void tcf_act_put_cookie(struct flow_action_entry *entry)
 {
     flow_action_cookie_destroy(entry->cookie);
 }
 
 void tc_cleanup_offload_action(struct flow_action *flow_action)
 {
     struct flow_action_entry *entry;
     int i;
 
     flow_action_for_each(i, entry, flow_action) {
         tcf_act_put_cookie(entry);
         if (entry->destructor)
             entry->destructor(entry->destructor_priv);
     }
 }
 EXPORT_SYMBOL(tc_cleanup_offload_action);
 
 static int tc_setup_offload_act(struct tc_action *act,
                 struct flow_action_entry *entry,
                 u32 *index_inc,
                 struct netlink_ext_ack *extack)
 {
 #ifdef CONFIG_NET_CLS_ACT
     if (act->ops->offload_act_setup) {
         return act->ops->offload_act_setup(act, entry, index_inc, true,
                            extack);
     } else {
         NL_SET_ERR_MSG(extack, "Action does not support offload");
         return -EOPNOTSUPP;
     }
 #else
     return 0;
 #endif
 }
 
 int tc_setup_action(struct flow_action *flow_action,
             struct tc_action *actions[],
             struct netlink_ext_ack *extack)
 {
     int i, j, k, index, err = 0;
     struct tc_action *act;
 
     BUILD_BUG_ON(TCA_ACT_HW_STATS_ANY != FLOW_ACTION_HW_STATS_ANY);
     BUILD_BUG_ON(TCA_ACT_HW_STATS_IMMEDIATE != FLOW_ACTION_HW_STATS_IMMEDIATE);
     BUILD_BUG_ON(TCA_ACT_HW_STATS_DELAYED != FLOW_ACTION_HW_STATS_DELAYED);
 
     if (!actions)
         return 0;
 
     j = 0;
     tcf_act_for_each_action(i, act, actions) {
         struct flow_action_entry *entry;
 
         entry = &flow_action->entries[j];
         spin_lock_bh(&act->tcfa_lock);
         err = tcf_act_get_cookie(entry, act);
         if (err)
             goto err_out_locked;
 
         index = 0;
         err = tc_setup_offload_act(act, entry, &index, extack);
         if (err)
             goto err_out_locked;
 
         for (k = 0; k < index ; k++) {
             entry[k].hw_stats = tc_act_hw_stats(act->hw_stats);
             entry[k].hw_index = act->tcfa_index;
         }
 
         j += index;
 
         spin_unlock_bh(&act->tcfa_lock);
     }
 
 err_out:
     if (err)
         tc_cleanup_offload_action(flow_action);
 
     return err;
 err_out_locked:
     spin_unlock_bh(&act->tcfa_lock);
     goto err_out;
 }
 
 int tc_setup_offload_action(struct flow_action *flow_action,
                 const struct tcf_exts *exts,
                 struct netlink_ext_ack *extack)
 {
 #ifdef CONFIG_NET_CLS_ACT
     if (!exts)
         return 0;
 
     return tc_setup_action(flow_action, exts->actions, extack);
 #else
     return 0;
 #endif
 }
 EXPORT_SYMBOL(tc_setup_offload_action);
 
 unsigned int tcf_exts_num_actions(struct tcf_exts *exts)
 {
     unsigned int num_acts = 0;
     struct tc_action *act;
     int i;
 
     tcf_exts_for_each_action(i, act, exts) {
         if (is_tcf_pedit(act))
             num_acts += tcf_pedit_nkeys(act);
         else
             num_acts++;
     }
     return num_acts;
 }
 EXPORT_SYMBOL(tcf_exts_num_actions);
 
 #ifdef CONFIG_NET_CLS_ACT
 static int tcf_qevent_parse_block_index(struct nlattr *block_index_attr,
                     u32 *p_block_index,
                     struct netlink_ext_ack *extack)
 {
     *p_block_index = nla_get_u32(block_index_attr);
     if (!*p_block_index) {
         NL_SET_ERR_MSG(extack, "Block number may not be zero");
         return -EINVAL;
     }
 
     return 0;
 }
 
 int tcf_qevent_init(struct tcf_qevent *qe, struct Qdisc *sch,
             enum flow_block_binder_type binder_type,
             struct nlattr *block_index_attr,
             struct netlink_ext_ack *extack)
 {
     u32 block_index;
     int err;
 
     if (!block_index_attr)
         return 0;
 
     err = tcf_qevent_parse_block_index(block_index_attr, &block_index, extack);
     if (err)
         return err;
 
     if (!block_index)
         return 0;
 
     qe->info.binder_type = binder_type;
     qe->info.chain_head_change = tcf_chain_head_change_dflt;
     qe->info.chain_head_change_priv = &qe->filter_chain;
     qe->info.block_index = block_index;
 
     return tcf_block_get_ext(&qe->block, sch, &qe->info, extack);
 }
 EXPORT_SYMBOL(tcf_qevent_init);
 
 void tcf_qevent_destroy(struct tcf_qevent *qe, struct Qdisc *sch)
 {
     if (qe->info.block_index)
         tcf_block_put_ext(qe->block, sch, &qe->info);
 }
 EXPORT_SYMBOL(tcf_qevent_destroy);
 
 int tcf_qevent_validate_change(struct tcf_qevent *qe, struct nlattr *block_index_attr,
                    struct netlink_ext_ack *extack)
 {
     u32 block_index;
     int err;
 
     if (!block_index_attr)
         return 0;
 
     err = tcf_qevent_parse_block_index(block_index_attr, &block_index, extack);
     if (err)
         return err;
 
     /* Bounce newly-configured block or change in block. */
     if (block_index != qe->info.block_index) {
         NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
         return -EINVAL;
     }
 
     return 0;
 }
 EXPORT_SYMBOL(tcf_qevent_validate_change);
 
 struct sk_buff *tcf_qevent_handle(struct tcf_qevent *qe, struct Qdisc *sch, struct sk_buff *skb,
                   struct sk_buff **to_free, int *ret)
 {
     struct tcf_result cl_res;
     struct tcf_proto *fl;
 
     if (!qe->info.block_index)
         return skb;
 
     fl = rcu_dereference_bh(qe->filter_chain);
 
     switch (tcf_classify(skb, NULL, fl, &cl_res, false)) {
     case TC_ACT_SHOT:
         qdisc_qstats_drop(sch);
         __qdisc_drop(skb, to_free);
         *ret = __NET_XMIT_BYPASS;
         return NULL;
     case TC_ACT_STOLEN:
     case TC_ACT_QUEUED:
     case TC_ACT_TRAP:
         __qdisc_drop(skb, to_free);
         *ret = __NET_XMIT_STOLEN;
         return NULL;
     case TC_ACT_REDIRECT:
         skb_do_redirect(skb);
         *ret = __NET_XMIT_STOLEN;
         return NULL;
     }
 
     return skb;
 }
 EXPORT_SYMBOL(tcf_qevent_handle);
 
 int tcf_qevent_dump(struct sk_buff *skb, int attr_name, struct tcf_qevent *qe)
 {
     if (!qe->info.block_index)
         return 0;
     return nla_put_u32(skb, attr_name, qe->info.block_index);
 }
 EXPORT_SYMBOL(tcf_qevent_dump);
 #endif
 
 static __net_init int tcf_net_init(struct net *net)
 {
     struct tcf_net *tn = net_generic(net, tcf_net_id);
 
     spin_lock_init(&tn->idr_lock);
     idr_init(&tn->idr);
     return 0;
 }
 
 static void __net_exit tcf_net_exit(struct net *net)
 {
     struct tcf_net *tn = net_generic(net, tcf_net_id);
 
     idr_destroy(&tn->idr);
 }
 
 static struct pernet_operations tcf_net_ops = {
     .init = tcf_net_init,
     .exit = tcf_net_exit,
     .id   = &tcf_net_id,
     .size = sizeof(struct tcf_net),
 };
 
 static int __init tc_filter_init(void)
 {
     int err;
 
     tc_filter_wq = alloc_ordered_workqueue("tc_filter_workqueue", 0);
     if (!tc_filter_wq)
         return -ENOMEM;
 
     err = register_pernet_subsys(&tcf_net_ops);
     if (err)
         goto err_register_pernet_subsys;
 
     rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_new_tfilter, NULL,
               RTNL_FLAG_DOIT_UNLOCKED);
     rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_del_tfilter, NULL,
               RTNL_FLAG_DOIT_UNLOCKED);
     rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_get_tfilter,
               tc_dump_tfilter, RTNL_FLAG_DOIT_UNLOCKED);
     rtnl_register(PF_UNSPEC, RTM_NEWCHAIN, tc_ctl_chain, NULL, 0);
     rtnl_register(PF_UNSPEC, RTM_DELCHAIN, tc_ctl_chain, NULL, 0);
     rtnl_register(PF_UNSPEC, RTM_GETCHAIN, tc_ctl_chain,
               tc_dump_chain, 0);
 
     return 0;
 
 err_register_pernet_subsys:
     destroy_workqueue(tc_filter_wq);
     return err;
 }
 
 subsys_initcall(tc_filter_init);