Merge branch 'net-speedup-netns-dismantles'

Eric Dumazet says:

====================
net: speedup netns dismantles

From: Eric Dumazet <edumazet@google.com>

In this series, I made network namespace deletions more scalable,
by 4x on the little benchmark described in this cover letter.

- Remove bottleneck on ipv6 addrconf, by replacing a global
  hash table to a per netns one.

- Rework many (struct pernet_operations)->exit() handlers to
  exit_batch() ones. This removes many rtnl acquisitions,
  and gives to cleanup_net() kind of a priority over rtnl
  ownership.

Tested on a host with 24 cpus (48 HT)

Test script:

for nr in {1..10}
do
  (for i in {1..10000}; do unshare -n /bin/bash -c "ifconfig lo up"; done) &
done
wait

for i in {1..10}
do
  sleep 1
  echo 3 >/proc/sys/vm/drop_caches
  grep net_namespace /proc/slabinfo
done

Before: We can see host struggles to clean the netns, even after there are no new creations.
Memory cost is high, because each netns consumes a good amount of memory.

time ./unshare10.sh
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      82634  82634   3968    1    1 : tunables   24   12    8 : slabdata  82634  82634      0
net_namespace      37214  37792   3968    1    1 : tunables   24   12    8 : slabdata  37214  37792    192

real	6m57.766s
user	3m37.277s
sys	40m4.826s

After: We can see the script completes much faster,
the kernel thread doing the cleanup_net() keeps up just fine.
Memory cost is not too big.

time ./unshare10.sh
net_namespace       9945   9945   4096    1    1 : tunables   24   12    8 : slabdata   9945   9945      0
net_namespace       4087   4665   4096    1    1 : tunables   24   12    8 : slabdata   4087   4665    192
net_namespace       4082   4607   4096    1    1 : tunables   24   12    8 : slabdata   4082   4607    192
net_namespace        234    761   4096    1    1 : tunables   24   12    8 : slabdata    234    761    192
net_namespace        224    751   4096    1    1 : tunables   24   12    8 : slabdata    224    751    192
net_namespace        218    745   4096    1    1 : tunables   24   12    8 : slabdata    218    745    192
net_namespace        193    667   4096    1    1 : tunables   24   12    8 : slabdata    193    667    172
net_namespace        167    609   4096    1    1 : tunables   24   12    8 : slabdata    167    609    152
net_namespace        167    609   4096    1    1 : tunables   24   12    8 : slabdata    167    609    152
net_namespace        157    609   4096    1    1 : tunables   24   12    8 : slabdata    157    609    152

real    1m43.876s
user    3m39.728s
sys 7m36.342s
====================

Link: https://lore.kernel.org/r/20220208045038.2635826-1-eric.dumazet@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/bonding/bond_main.c

@@ -6048,27 +6048,38 @@ static int __net_init bond_net_init(struct net *net)
 	return 0;
 }
 
-static void __net_exit bond_net_exit(struct net *net)
+static void __net_exit bond_net_exit_batch(struct list_head *net_list)
 {
-	struct bond_net *bn = net_generic(net, bond_net_id);
-	struct bonding *bond, *tmp_bond;
+	struct bond_net *bn;
+	struct net *net;
 	LIST_HEAD(list);
 
-	bond_destroy_sysfs(bn);
+	list_for_each_entry(net, net_list, exit_list) {
+		bn = net_generic(net, bond_net_id);
+		bond_destroy_sysfs(bn);
+	}
 
 	/* Kill off any bonds created after unregistering bond rtnl ops */
 	rtnl_lock();
-	list_for_each_entry_safe(bond, tmp_bond, &bn->dev_list, bond_list)
-		unregister_netdevice_queue(bond->dev, &list);
+	list_for_each_entry(net, net_list, exit_list) {
+		struct bonding *bond, *tmp_bond;
+
+		bn = net_generic(net, bond_net_id);
+		list_for_each_entry_safe(bond, tmp_bond, &bn->dev_list, bond_list)
+			unregister_netdevice_queue(bond->dev, &list);
+	}
 	unregister_netdevice_many(&list);
 	rtnl_unlock();
 
-	bond_destroy_proc_dir(bn);
+	list_for_each_entry(net, net_list, exit_list) {
+		bn = net_generic(net, bond_net_id);
+		bond_destroy_proc_dir(bn);
+	}
 }
 
 static struct pernet_operations bond_net_ops = {
 	.init = bond_net_init,
-	.exit = bond_net_exit,
+	.exit_batch = bond_net_exit_batch,
 	.id   = &bond_net_id,
 	.size = sizeof(struct bond_net),
 };

drivers/net/bonding/bond_procfs.c

@@ -307,7 +307,6 @@ void __net_init bond_create_proc_dir(struct bond_net *bn)
 }
 
 /* Destroy the bonding directory under /proc/net, if empty.
- * Caller must hold rtnl_lock.
  */
 void __net_exit bond_destroy_proc_dir(struct bond_net *bn)
 {

include/net/netns/ipv6.h

@@ -92,6 +92,11 @@ struct netns_ipv6 {
 	struct sock             *tcp_sk;
 	struct sock             *igmp_sk;
 	struct sock		*mc_autojoin_sk;
+
+	struct hlist_head	*inet6_addr_lst;
+	spinlock_t		addrconf_hash_lock;
+	struct delayed_work	addr_chk_work;
+
 #ifdef CONFIG_IPV6_MROUTE
 #ifndef CONFIG_IPV6_MROUTE_MULTIPLE_TABLES
 	struct mr_table		*mrt6;

net/can/gw.c

@@ -1239,16 +1239,19 @@ static int __net_init cangw_pernet_init(struct net *net)
 	return 0;
 }
 
-static void __net_exit cangw_pernet_exit(struct net *net)
+static void __net_exit cangw_pernet_exit_batch(struct list_head *net_list)
 {
+	struct net *net;
+
 	rtnl_lock();
-	cgw_remove_all_jobs(net);
+	list_for_each_entry(net, net_list, exit_list)
+		cgw_remove_all_jobs(net);
 	rtnl_unlock();
 }
 
 static struct pernet_operations cangw_pernet_ops = {
 	.init = cangw_pernet_init,
-	.exit = cangw_pernet_exit,
+	.exit_batch = cangw_pernet_exit_batch,
 };
 
 static __init int cgw_module_init(void)

net/core/dev.c

@@ -10850,14 +10850,14 @@ static struct pernet_operations __net_initdata netdev_net_ops = {
 	.exit = netdev_exit,
 };
 
-static void __net_exit default_device_exit(struct net *net)
+static void __net_exit default_device_exit_net(struct net *net)
 {
 	struct net_device *dev, *aux;
 	/*
 	 * Push all migratable network devices back to the
 	 * initial network namespace
 	 */
-	rtnl_lock();
+	ASSERT_RTNL();
 	for_each_netdev_safe(net, dev, aux) {
 		int err;
 		char fb_name[IFNAMSIZ];
@@ -10881,22 +10881,22 @@ static void __net_exit default_device_exit(struct net *net)
 			BUG();
 		}
 	}
-	rtnl_unlock();
 }
 
 static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
 {
-	/* Return with the rtnl_lock held when there are no network
+	/* Return (with the rtnl_lock held) when there are no network
 	 * devices unregistering in any network namespace in net_list.
 	 */
-	struct net *net;
-	bool unregistering;
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	bool unregistering;
+	struct net *net;
 
+	ASSERT_RTNL();
 	add_wait_queue(&netdev_unregistering_wq, &wait);
 	for (;;) {
 		unregistering = false;
-		rtnl_lock();
+
 		list_for_each_entry(net, net_list, exit_list) {
 			if (net->dev_unreg_count > 0) {
 				unregistering = true;
@@ -10908,6 +10908,7 @@ static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
 		__rtnl_unlock();
 
 		wait_woken(&wait, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+		rtnl_lock();
 	}
 	remove_wait_queue(&netdev_unregistering_wq, &wait);
 }
@@ -10923,6 +10924,11 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
 	struct net *net;
 	LIST_HEAD(dev_kill_list);
 
+	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list) {
+		default_device_exit_net(net);
+		cond_resched();
+	}
 	/* To prevent network device cleanup code from dereferencing
 	 * loopback devices or network devices that have been freed
 	 * wait here for all pending unregistrations to complete,
@@ -10935,6 +10941,7 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
 	 * default_device_exit_batch.
 	 */
 	rtnl_lock_unregistering(net_list);
+
 	list_for_each_entry(net, net_list, exit_list) {
 		for_each_netdev_reverse(net, dev) {
 			if (dev->rtnl_link_ops && dev->rtnl_link_ops->dellink)
@@ -10948,7 +10955,6 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
 }
 
 static struct pernet_operations __net_initdata default_device_ops = {
-	.exit = default_device_exit,
 	.exit_batch = default_device_exit_batch,
 };
 

net/ipv4/fib_frontend.c

@@ -1556,7 +1556,7 @@ static void ip_fib_net_exit(struct net *net)
 {
 	int i;
 
-	rtnl_lock();
+	ASSERT_RTNL();
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
 	RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
@@ -1581,7 +1581,7 @@ static void ip_fib_net_exit(struct net *net)
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	fib4_rules_exit(net);
 #endif
-	rtnl_unlock();
+
 	kfree(net->ipv4.fib_table_hash);
 	fib4_notifier_exit(net);
 }
@@ -1608,7 +1608,9 @@ static int __net_init fib_net_init(struct net *net)
 out_proc:
 	nl_fib_lookup_exit(net);
 out_nlfl:
+	rtnl_lock();
 	ip_fib_net_exit(net);
+	rtnl_unlock();
 	goto out;
 }
 
@@ -1616,12 +1618,23 @@ static void __net_exit fib_net_exit(struct net *net)
 {
 	fib_proc_exit(net);
 	nl_fib_lookup_exit(net);
-	ip_fib_net_exit(net);
+}
+
+static void __net_exit fib_net_exit_batch(struct list_head *net_list)
+{
+	struct net *net;
+
+	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list)
+		ip_fib_net_exit(net);
+
+	rtnl_unlock();
 }
 
 static struct pernet_operations fib_net_ops = {
 	.init = fib_net_init,
 	.exit = fib_net_exit,
+	.exit_batch = fib_net_exit_batch,
 };
 
 void __init ip_fib_init(void)

net/ipv4/ipmr.c

@@ -266,13 +266,12 @@ static void __net_exit ipmr_rules_exit(struct net *net)
 {
 	struct mr_table *mrt, *next;
 
-	rtnl_lock();
+	ASSERT_RTNL();
 	list_for_each_entry_safe(mrt, next, &net->ipv4.mr_tables, list) {
 		list_del(&mrt->list);
 		ipmr_free_table(mrt);
 	}
 	fib_rules_unregister(net->ipv4.mr_rules_ops);
-	rtnl_unlock();
 }
 
 static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
@@ -328,10 +327,9 @@ static int __net_init ipmr_rules_init(struct net *net)
 
 static void __net_exit ipmr_rules_exit(struct net *net)
 {
-	rtnl_lock();
+	ASSERT_RTNL();
 	ipmr_free_table(net->ipv4.mrt);
 	net->ipv4.mrt = NULL;
-	rtnl_unlock();
 }
 
 static int ipmr_rules_dump(struct net *net, struct notifier_block *nb,
@@ -3075,7 +3073,9 @@ static int __net_init ipmr_net_init(struct net *net)
 proc_cache_fail:
 	remove_proc_entry("ip_mr_vif", net->proc_net);
 proc_vif_fail:
+	rtnl_lock();
 	ipmr_rules_exit(net);
+	rtnl_unlock();
 #endif
 ipmr_rules_fail:
 	ipmr_notifier_exit(net);
@@ -3090,12 +3090,22 @@ static void __net_exit ipmr_net_exit(struct net *net)
 	remove_proc_entry("ip_mr_vif", net->proc_net);
 #endif
 	ipmr_notifier_exit(net);
-	ipmr_rules_exit(net);
+}
+
+static void __net_exit ipmr_net_exit_batch(struct list_head *net_list)
+{
+	struct net *net;
+
+	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list)
+		ipmr_rules_exit(net);
+	rtnl_unlock();
 }
 
 static struct pernet_operations ipmr_net_ops = {
 	.init = ipmr_net_init,
 	.exit = ipmr_net_exit,
+	.exit_batch = ipmr_net_exit_batch,
 };
 
 int __init ip_mr_init(void)

net/ipv4/nexthop.c

@@ -3733,12 +3733,16 @@ void nexthop_res_grp_activity_update(struct net *net, u32 id, u16 num_buckets,
 }
 EXPORT_SYMBOL(nexthop_res_grp_activity_update);
 
-static void __net_exit nexthop_net_exit(struct net *net)
+static void __net_exit nexthop_net_exit_batch(struct list_head *net_list)
 {
+	struct net *net;
+
 	rtnl_lock();
-	flush_all_nexthops(net);
+	list_for_each_entry(net, net_list, exit_list) {
+		flush_all_nexthops(net);
+		kfree(net->nexthop.devhash);
+	}
 	rtnl_unlock();
-	kfree(net->nexthop.devhash);
 }
 
 static int __net_init nexthop_net_init(struct net *net)
@@ -3756,7 +3760,7 @@ static int __net_init nexthop_net_init(struct net *net)
 
 static struct pernet_operations nexthop_net_ops = {
 	.init = nexthop_net_init,
-	.exit = nexthop_net_exit,
+	.exit_batch = nexthop_net_exit_batch,
 };
 
 static int __init nexthop_init(void)

net/ipv6/addrconf.c

@@ -146,18 +146,11 @@ static int ipv6_generate_stable_address(struct in6_addr *addr,
 
 #define IN6_ADDR_HSIZE_SHIFT	8
 #define IN6_ADDR_HSIZE		(1 << IN6_ADDR_HSIZE_SHIFT)
-/*
- *	Configured unicast address hash table
- */
-static struct hlist_head inet6_addr_lst[IN6_ADDR_HSIZE];
-static DEFINE_SPINLOCK(addrconf_hash_lock);
 
-static void addrconf_verify(void);
-static void addrconf_verify_rtnl(void);
-static void addrconf_verify_work(struct work_struct *);
+static void addrconf_verify(struct net *net);
+static void addrconf_verify_rtnl(struct net *net);
 
 static struct workqueue_struct *addrconf_wq;
-static DECLARE_DELAYED_WORK(addr_chk_work, addrconf_verify_work);
 
 static void addrconf_join_anycast(struct inet6_ifaddr *ifp);
 static void addrconf_leave_anycast(struct inet6_ifaddr *ifp);
@@ -1011,9 +1004,7 @@ static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
 {
 	struct inet6_ifaddr *ifp;
 
-	hlist_for_each_entry(ifp, &inet6_addr_lst[hash], addr_lst) {
-		if (!net_eq(dev_net(ifp->idev->dev), net))
-			continue;
+	hlist_for_each_entry(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
 		if (ipv6_addr_equal(&ifp->addr, addr)) {
 			if (!dev || ifp->idev->dev == dev)
 				return true;
@@ -1024,20 +1015,21 @@ static bool ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
 
 static int ipv6_add_addr_hash(struct net_device *dev, struct inet6_ifaddr *ifa)
 {
-	unsigned int hash = inet6_addr_hash(dev_net(dev), &ifa->addr);
+	struct net *net = dev_net(dev);
+	unsigned int hash = inet6_addr_hash(net, &ifa->addr);
 	int err = 0;
 
-	spin_lock(&addrconf_hash_lock);
+	spin_lock(&net->ipv6.addrconf_hash_lock);
 
 	/* Ignore adding duplicate addresses on an interface */
-	if (ipv6_chk_same_addr(dev_net(dev), &ifa->addr, dev, hash)) {
+	if (ipv6_chk_same_addr(net, &ifa->addr, dev, hash)) {
 		netdev_dbg(dev, "ipv6_add_addr: already assigned\n");
 		err = -EEXIST;
 	} else {
-		hlist_add_head_rcu(&ifa->addr_lst, &inet6_addr_lst[hash]);
+		hlist_add_head_rcu(&ifa->addr_lst, &net->ipv6.inet6_addr_lst[hash]);
 	}
 
-	spin_unlock(&addrconf_hash_lock);
+	spin_unlock(&net->ipv6.addrconf_hash_lock);
 
 	return err;
 }
@@ -1261,9 +1253,10 @@ cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires,
 
 static void ipv6_del_addr(struct inet6_ifaddr *ifp)
 {
-	int state;
 	enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_NOP;
+	struct net *net = dev_net(ifp->idev->dev);
 	unsigned long expires;
+	int state;
 
 	ASSERT_RTNL();
 
@@ -1275,9 +1268,9 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
 	if (state == INET6_IFADDR_STATE_DEAD)
 		goto out;
 
-	spin_lock_bh(&addrconf_hash_lock);
+	spin_lock_bh(&net->ipv6.addrconf_hash_lock);
 	hlist_del_init_rcu(&ifp->addr_lst);
-	spin_unlock_bh(&addrconf_hash_lock);
+	spin_unlock_bh(&net->ipv6.addrconf_hash_lock);
 
 	write_lock_bh(&ifp->idev->lock);
 
@@ -1920,10 +1913,8 @@ __ipv6_chk_addr_and_flags(struct net *net, const struct in6_addr *addr,
 	if (skip_dev_check)
 		dev = NULL;
 
-	hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
+	hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
 		ndev = ifp->idev->dev;
-		if (!net_eq(dev_net(ndev), net))
-			continue;
 
 		if (l3mdev_master_dev_rcu(ndev) != l3mdev)
 			continue;
@@ -2027,9 +2018,7 @@ struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *add
 	struct inet6_ifaddr *ifp, *result = NULL;
 
 	rcu_read_lock();
-	hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
-		if (!net_eq(dev_net(ifp->idev->dev), net))
-			continue;
+	hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
 		if (ipv6_addr_equal(&ifp->addr, addr)) {
 			if (!dev || ifp->idev->dev == dev ||
 			    !(ifp->scope&(IFA_LINK|IFA_HOST) || strict)) {
@@ -2096,7 +2085,7 @@ static int addrconf_dad_end(struct inet6_ifaddr *ifp)
 void addrconf_dad_failure(struct sk_buff *skb, struct inet6_ifaddr *ifp)
 {
 	struct inet6_dev *idev = ifp->idev;
-	struct net *net = dev_net(ifp->idev->dev);
+	struct net *net = dev_net(idev->dev);
 
 	if (addrconf_dad_end(ifp)) {
 		in6_ifa_put(ifp);
@@ -2675,7 +2664,7 @@ int addrconf_prefix_rcv_add_addr(struct net *net, struct net_device *dev,
 				 create, now);
 
 		in6_ifa_put(ifp);
-		addrconf_verify();
+		addrconf_verify(net);
 	}
 
 	return 0;
@@ -2987,7 +2976,7 @@ static int inet6_addr_add(struct net *net, int ifindex,
 			manage_tempaddrs(idev, ifp, cfg->valid_lft,
 					 cfg->preferred_lft, true, jiffies);
 		in6_ifa_put(ifp);
-		addrconf_verify_rtnl();
+		addrconf_verify_rtnl(net);
 		return 0;
 	} else if (cfg->ifa_flags & IFA_F_MCAUTOJOIN) {
 		ipv6_mc_config(net->ipv6.mc_autojoin_sk, false,
@@ -3027,7 +3016,7 @@ static int inet6_addr_del(struct net *net, int ifindex, u32 ifa_flags,
 				manage_tempaddrs(idev, ifp, 0, 0, false,
 						 jiffies);
 			ipv6_del_addr(ifp);
-			addrconf_verify_rtnl();
+			addrconf_verify_rtnl(net);
 			if (ipv6_addr_is_multicast(pfx)) {
 				ipv6_mc_config(net->ipv6.mc_autojoin_sk,
 					       false, pfx, dev->ifindex);
@@ -3772,9 +3761,9 @@ static int addrconf_ifdown(struct net_device *dev, bool unregister)
 
 	/* Step 2: clear hash table */
 	for (i = 0; i < IN6_ADDR_HSIZE; i++) {
-		struct hlist_head *h = &inet6_addr_lst[i];
+		struct hlist_head *h = &net->ipv6.inet6_addr_lst[i];
 
-		spin_lock_bh(&addrconf_hash_lock);
+		spin_lock_bh(&net->ipv6.addrconf_hash_lock);
 restart:
 		hlist_for_each_entry_rcu(ifa, h, addr_lst) {
 			if (ifa->idev == idev) {
@@ -3790,7 +3779,7 @@ static int addrconf_ifdown(struct net_device *dev, bool unregister)
 				}
 			}
 		}
-		spin_unlock_bh(&addrconf_hash_lock);
+		spin_unlock_bh(&net->ipv6.addrconf_hash_lock);
 	}
 
 	write_lock_bh(&idev->lock);
@@ -4246,7 +4235,7 @@ static void addrconf_dad_completed(struct inet6_ifaddr *ifp, bool bump_id,
 	 * before this temporary address becomes deprecated.
 	 */
 	if (ifp->flags & IFA_F_TEMPORARY)
-		addrconf_verify_rtnl();
+		addrconf_verify_rtnl(dev_net(dev));
 }
 
 static void addrconf_dad_run(struct inet6_dev *idev, bool restart)
@@ -4288,10 +4277,8 @@ static struct inet6_ifaddr *if6_get_first(struct seq_file *seq, loff_t pos)
 	}
 
 	for (; state->bucket < IN6_ADDR_HSIZE; ++state->bucket) {
-		hlist_for_each_entry_rcu(ifa, &inet6_addr_lst[state->bucket],
+		hlist_for_each_entry_rcu(ifa, &net->ipv6.inet6_addr_lst[state->bucket],
 					 addr_lst) {
-			if (!net_eq(dev_net(ifa->idev->dev), net))
-				continue;
 			/* sync with offset */
 			if (p < state->offset) {
 				p++;
@@ -4314,8 +4301,6 @@ static struct inet6_ifaddr *if6_get_next(struct seq_file *seq,
 	struct net *net = seq_file_net(seq);
 
 	hlist_for_each_entry_continue_rcu(ifa, addr_lst) {
-		if (!net_eq(dev_net(ifa->idev->dev), net))
-			continue;
 		state->offset++;
 		return ifa;
 	}
@@ -4323,9 +4308,7 @@ static struct inet6_ifaddr *if6_get_next(struct seq_file *seq,
 	state->offset = 0;
 	while (++state->bucket < IN6_ADDR_HSIZE) {
 		hlist_for_each_entry_rcu(ifa,
-				     &inet6_addr_lst[state->bucket], addr_lst) {
-			if (!net_eq(dev_net(ifa->idev->dev), net))
-				continue;
+				     &net->ipv6.inet6_addr_lst[state->bucket], addr_lst) {
 			return ifa;
 		}
 	}
@@ -4413,9 +4396,7 @@ int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr)
 	int ret = 0;
 
 	rcu_read_lock();
-	hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
-		if (!net_eq(dev_net(ifp->idev->dev), net))
-			continue;
+	hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
 		if (ipv6_addr_equal(&ifp->addr, addr) &&
 		    (ifp->flags & IFA_F_HOMEADDRESS)) {
 			ret = 1;
@@ -4453,9 +4434,7 @@ int ipv6_chk_rpl_srh_loop(struct net *net, const struct in6_addr *segs,
 		hash = inet6_addr_hash(net, addr);
 
 		hash_found = false;
-		hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
-			if (!net_eq(dev_net(ifp->idev->dev), net))
-				continue;
+		hlist_for_each_entry_rcu(ifp, &net->ipv6.inet6_addr_lst[hash], addr_lst) {
 
 			if (ipv6_addr_equal(&ifp->addr, addr)) {
 				hash_found = true;
@@ -4484,7 +4463,7 @@ int ipv6_chk_rpl_srh_loop(struct net *net, const struct in6_addr *segs,
  *	Periodic address status verification
  */
 
-static void addrconf_verify_rtnl(void)
+static void addrconf_verify_rtnl(struct net *net)
 {
 	unsigned long now, next, next_sec, next_sched;
 	struct inet6_ifaddr *ifp;
@@ -4496,11 +4475,11 @@ static void addrconf_verify_rtnl(void)
 	now = jiffies;
 	next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);
 
-	cancel_delayed_work(&addr_chk_work);
+	cancel_delayed_work(&net->ipv6.addr_chk_work);
 
 	for (i = 0; i < IN6_ADDR_HSIZE; i++) {
 restart:
-		hlist_for_each_entry_rcu_bh(ifp, &inet6_addr_lst[i], addr_lst) {
+		hlist_for_each_entry_rcu_bh(ifp, &net->ipv6.inet6_addr_lst[i], addr_lst) {
 			unsigned long age;
 
 			/* When setting preferred_lft to a value not zero or
@@ -4599,20 +4578,23 @@ static void addrconf_verify_rtnl(void)
 
 	pr_debug("now = %lu, schedule = %lu, rounded schedule = %lu => %lu\n",
 		 now, next, next_sec, next_sched);
-	mod_delayed_work(addrconf_wq, &addr_chk_work, next_sched - now);
+	mod_delayed_work(addrconf_wq, &net->ipv6.addr_chk_work, next_sched - now);
 	rcu_read_unlock_bh();
 }
 
 static void addrconf_verify_work(struct work_struct *w)
 {
+	struct net *net = container_of(to_delayed_work(w), struct net,
+				       ipv6.addr_chk_work);
+
 	rtnl_lock();
-	addrconf_verify_rtnl();
+	addrconf_verify_rtnl(net);
 	rtnl_unlock();
 }
 
-static void addrconf_verify(void)
+static void addrconf_verify(struct net *net)
 {
-	mod_delayed_work(addrconf_wq, &addr_chk_work, 0);
+	mod_delayed_work(addrconf_wq, &net->ipv6.addr_chk_work, 0);
 }
 
 static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local,
@@ -4708,7 +4690,8 @@ static int modify_prefix_route(struct inet6_ifaddr *ifp,
 	return 0;
 }
 
-static int inet6_addr_modify(struct inet6_ifaddr *ifp, struct ifa6_config *cfg)
+static int inet6_addr_modify(struct net *net, struct inet6_ifaddr *ifp,
+			     struct ifa6_config *cfg)
 {
 	u32 flags;
 	clock_t expires;
@@ -4822,7 +4805,7 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, struct ifa6_config *cfg)
 				 jiffies);
 	}
 
-	addrconf_verify_rtnl();
+	addrconf_verify_rtnl(net);
 
 	return 0;
 }
@@ -4909,7 +4892,7 @@ inet6_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
 	    !(nlh->nlmsg_flags & NLM_F_REPLACE))
 		err = -EEXIST;
 	else
-		err = inet6_addr_modify(ifa, &cfg);
+		err = inet6_addr_modify(net, ifa, &cfg);
 
 	in6_ifa_put(ifa);
 
@@ -5794,7 +5777,7 @@ static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token,
 
 	write_unlock_bh(&idev->lock);
 	inet6_ifinfo_notify(RTM_NEWLINK, idev);
-	addrconf_verify_rtnl();
+	addrconf_verify_rtnl(dev_net(dev));
 	return 0;
 }
 
@@ -7111,6 +7094,14 @@ static int __net_init addrconf_init_net(struct net *net)
 	int err = -ENOMEM;
 	struct ipv6_devconf *all, *dflt;
 
+	spin_lock_init(&net->ipv6.addrconf_hash_lock);
+	INIT_DEFERRABLE_WORK(&net->ipv6.addr_chk_work, addrconf_verify_work);
+	net->ipv6.inet6_addr_lst = kcalloc(IN6_ADDR_HSIZE,
+					   sizeof(struct hlist_head),
+					   GFP_KERNEL);
+	if (!net->ipv6.inet6_addr_lst)
+		goto err_alloc_addr;
+
 	all = kmemdup(&ipv6_devconf, sizeof(ipv6_devconf), GFP_KERNEL);
 	if (!all)
 		goto err_alloc_all;
@@ -7172,11 +7163,15 @@ static int __net_init addrconf_init_net(struct net *net)
 err_alloc_dflt:
 	kfree(all);
 err_alloc_all:
+	kfree(net->ipv6.inet6_addr_lst);
+err_alloc_addr:
 	return err;
 }
 
 static void __net_exit addrconf_exit_net(struct net *net)
 {
+	int i;
+
 #ifdef CONFIG_SYSCTL
 	__addrconf_sysctl_unregister(net, net->ipv6.devconf_dflt,
 				     NETCONFA_IFINDEX_DEFAULT);
@@ -7187,6 +7182,16 @@ static void __net_exit addrconf_exit_net(struct net *net)
 	net->ipv6.devconf_dflt = NULL;
 	kfree(net->ipv6.devconf_all);
 	net->ipv6.devconf_all = NULL;
+
+	cancel_delayed_work(&net->ipv6.addr_chk_work);
+	/*
+	 *	Check hash table, then free it.
+	 */
+	for (i = 0; i < IN6_ADDR_HSIZE; i++)
+		WARN_ON_ONCE(!hlist_empty(&net->ipv6.inet6_addr_lst[i]));
+
+	kfree(net->ipv6.inet6_addr_lst);
+	net->ipv6.inet6_addr_lst = NULL;
 }
 
 static struct pernet_operations addrconf_ops = {
@@ -7209,7 +7214,7 @@ static struct rtnl_af_ops inet6_ops __read_mostly = {
 int __init addrconf_init(void)
 {
 	struct inet6_dev *idev;
-	int i, err;
+	int err;
 
 	err = ipv6_addr_label_init();
 	if (err < 0) {
@@ -7256,12 +7261,9 @@ int __init addrconf_init(void)
 
 	ip6_route_init_special_entries();
 
-	for (i = 0; i < IN6_ADDR_HSIZE; i++)
-		INIT_HLIST_HEAD(&inet6_addr_lst[i]);
-
 	register_netdevice_notifier(&ipv6_dev_notf);
 
-	addrconf_verify();
+	addrconf_verify(&init_net);
 
 	rtnl_af_register(&inet6_ops);
 
@@ -7319,7 +7321,6 @@ int __init addrconf_init(void)
 void addrconf_cleanup(void)
 {
 	struct net_device *dev;
-	int i;
 
 	unregister_netdevice_notifier(&ipv6_dev_notf);
 	unregister_pernet_subsys(&addrconf_ops);
@@ -7337,14 +7338,6 @@ void addrconf_cleanup(void)
 	}
 	addrconf_ifdown(init_net.loopback_dev, true);
 
-	/*
-	 *	Check hash table.
-	 */
-	spin_lock_bh(&addrconf_hash_lock);
-	for (i = 0; i < IN6_ADDR_HSIZE; i++)
-		WARN_ON(!hlist_empty(&inet6_addr_lst[i]));
-	spin_unlock_bh(&addrconf_hash_lock);
-	cancel_delayed_work(&addr_chk_work);
 	rtnl_unlock();
 
 	destroy_workqueue(addrconf_wq);

net/ipv6/fib6_rules.c

@@ -493,16 +493,21 @@ static int __net_init fib6_rules_net_init(struct net *net)
 	goto out;
 }
 
-static void __net_exit fib6_rules_net_exit(struct net *net)
+static void __net_exit fib6_rules_net_exit_batch(struct list_head *net_list)
 {
+	struct net *net;
+
 	rtnl_lock();
-	fib_rules_unregister(net->ipv6.fib6_rules_ops);
+	list_for_each_entry(net, net_list, exit_list) {
+		fib_rules_unregister(net->ipv6.fib6_rules_ops);
+		cond_resched();
+	}
 	rtnl_unlock();
 }
 
 static struct pernet_operations fib6_rules_net_ops = {
 	.init = fib6_rules_net_init,
-	.exit = fib6_rules_net_exit,
+	.exit_batch = fib6_rules_net_exit_batch,
 };
 
 int __init fib6_rules_init(void)

net/ipv6/ip6mr.c

@@ -253,13 +253,12 @@ static void __net_exit ip6mr_rules_exit(struct net *net)
 {
 	struct mr_table *mrt, *next;
 
-	rtnl_lock();
+	ASSERT_RTNL();
 	list_for_each_entry_safe(mrt, next, &net->ipv6.mr6_tables, list) {
 		list_del(&mrt->list);
 		ip6mr_free_table(mrt);
 	}
 	fib_rules_unregister(net->ipv6.mr6_rules_ops);
-	rtnl_unlock();
 }
 
 static int ip6mr_rules_dump(struct net *net, struct notifier_block *nb,
@@ -316,10 +315,9 @@ static int __net_init ip6mr_rules_init(struct net *net)
 
 static void __net_exit ip6mr_rules_exit(struct net *net)
 {
-	rtnl_lock();
+	ASSERT_RTNL();
 	ip6mr_free_table(net->ipv6.mrt6);
 	net->ipv6.mrt6 = NULL;
-	rtnl_unlock();
 }
 
 static int ip6mr_rules_dump(struct net *net, struct notifier_block *nb,
@@ -1323,7 +1321,9 @@ static int __net_init ip6mr_net_init(struct net *net)
 proc_cache_fail:
 	remove_proc_entry("ip6_mr_vif", net->proc_net);
 proc_vif_fail:
+	rtnl_lock();
 	ip6mr_rules_exit(net);
+	rtnl_unlock();
 #endif
 ip6mr_rules_fail:
 	ip6mr_notifier_exit(net);
@@ -1336,13 +1336,23 @@ static void __net_exit ip6mr_net_exit(struct net *net)
 	remove_proc_entry("ip6_mr_cache", net->proc_net);
 	remove_proc_entry("ip6_mr_vif", net->proc_net);
 #endif
-	ip6mr_rules_exit(net);
 	ip6mr_notifier_exit(net);
 }
 
+static void __net_exit ip6mr_net_exit_batch(struct list_head *net_list)
+{
+	struct net *net;
+
+	rtnl_lock();
+	list_for_each_entry(net, net_list, exit_list)
+		ip6mr_rules_exit(net);
+	rtnl_unlock();
+}
+
 static struct pernet_operations ip6mr_net_ops = {
 	.init = ip6mr_net_init,
 	.exit = ip6mr_net_exit,
+	.exit_batch = ip6mr_net_exit_batch,
 };
 
 int __init ip6_mr_init(void)