Merge branch 'netns-speedup-dismantle'

Eric Dumazet says:

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

netns are dismantled by a single thread, from cleanup_net()

On hosts with many TCP sockets, and/or many cpus, this thread
is spending too many cpu cycles, and can not keep up with some
workloads.

- Removing 3*num_possible_cpus() sockets per netns, for icmp and tcp protocols.
- Iterating over all TCP sockets to remove stale timewait sockets.

This patch series removes ~50% of cleanup_net() cpu costs on
hosts with 256 cpus. It also reduces per netns memory footprint.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/inet_timewait_sock.h

@@ -65,13 +65,13 @@ struct inet_timewait_sock {
 	/* these three are in inet_sock */
 	__be16			tw_sport;
 	/* And these are ours. */
-	unsigned int		tw_kill		: 1,
-				tw_transparent  : 1,
+	unsigned int		tw_transparent  : 1,
 				tw_flowlabel	: 20,
-				tw_pad		: 2,	/* 2 bits hole */
+				tw_pad		: 3,	/* 3 bits hole */
 				tw_tos		: 8;
 	u32			tw_txhash;
 	u32			tw_priority;
+	u32			tw_bslot; /* bind bucket slot */
 	struct timer_list	tw_timer;
 	struct inet_bind_bucket	*tw_tb;
 };
@@ -110,8 +110,6 @@ static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo
 
 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
 
-void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
-
 static inline
 struct net *twsk_net(const struct inet_timewait_sock *twsk)
 {

include/net/netns/ipv4.h

@@ -70,11 +70,9 @@ struct netns_ipv4 {
 	struct hlist_head	*fib_table_hash;
 	struct sock		*fibnl;
 
-	struct sock  * __percpu	*icmp_sk;
 	struct sock		*mc_autojoin_sk;
 
 	struct inet_peer_base	*peers;
-	struct sock  * __percpu	*tcp_sk;
 	struct fqdir		*fqdir;
 
 	u8 sysctl_icmp_echo_ignore_all;

include/net/netns/ipv6.h

@@ -88,7 +88,6 @@ struct netns_ipv6 {
 	struct fib6_table       *fib6_local_tbl;
 	struct fib_rules_ops    *fib6_rules_ops;
 #endif
-	struct sock * __percpu	*icmp_sk;
 	struct sock             *ndisc_sk;
 	struct sock             *tcp_sk;
 	struct sock             *igmp_sk;

net/dccp/ipv4.c

@@ -1030,15 +1030,9 @@ static void __net_exit dccp_v4_exit_net(struct net *net)
 	inet_ctl_sock_destroy(pn->v4_ctl_sk);
 }
 
-static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
-{
-	inet_twsk_purge(&dccp_hashinfo, AF_INET);
-}
-
 static struct pernet_operations dccp_v4_ops = {
 	.init	= dccp_v4_init_net,
 	.exit	= dccp_v4_exit_net,
-	.exit_batch = dccp_v4_exit_batch,
 	.id	= &dccp_v4_pernet_id,
 	.size   = sizeof(struct dccp_v4_pernet),
 };

net/dccp/ipv6.c

@@ -1115,15 +1115,9 @@ static void __net_exit dccp_v6_exit_net(struct net *net)
 	inet_ctl_sock_destroy(pn->v6_ctl_sk);
 }
 
-static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
-{
-	inet_twsk_purge(&dccp_hashinfo, AF_INET6);
-}
-
 static struct pernet_operations dccp_v6_ops = {
 	.init   = dccp_v6_init_net,
 	.exit   = dccp_v6_exit_net,
-	.exit_batch = dccp_v6_exit_batch,
 	.id	= &dccp_v6_pernet_id,
 	.size   = sizeof(struct dccp_v6_pernet),
 };

net/ipv4/icmp.c

@@ -192,24 +192,14 @@ struct icmp_control {
 
 static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1];
 
-/*
- *	The ICMP socket(s). This is the most convenient way to flow control
- *	our ICMP output as well as maintain a clean interface throughout
- *	all layers. All Socketless IP sends will soon be gone.
- *
- *	On SMP we have one ICMP socket per-cpu.
- */
-static struct sock *icmp_sk(struct net *net)
-{
-	return this_cpu_read(*net->ipv4.icmp_sk);
-}
+static DEFINE_PER_CPU(struct sock *, ipv4_icmp_sk);
 
 /* Called with BH disabled */
 static inline struct sock *icmp_xmit_lock(struct net *net)
 {
 	struct sock *sk;
 
-	sk = icmp_sk(net);
+	sk = this_cpu_read(ipv4_icmp_sk);
 
 	if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
 		/* This can happen if the output path signals a
@@ -217,11 +207,13 @@ static inline struct sock *icmp_xmit_lock(struct net *net)
 		 */
 		return NULL;
 	}
+	sock_net_set(sk, net);
 	return sk;
 }
 
 static inline void icmp_xmit_unlock(struct sock *sk)
 {
+	sock_net_set(sk, &init_net);
 	spin_unlock(&sk->sk_lock.slock);
 }
 
@@ -363,14 +355,13 @@ static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd,
 	return 0;
 }
 
-static void icmp_push_reply(struct icmp_bxm *icmp_param,
+static void icmp_push_reply(struct sock *sk,
+			    struct icmp_bxm *icmp_param,
 			    struct flowi4 *fl4,
 			    struct ipcm_cookie *ipc, struct rtable **rt)
 {
-	struct sock *sk;
 	struct sk_buff *skb;
 
-	sk = icmp_sk(dev_net((*rt)->dst.dev));
 	if (ip_append_data(sk, fl4, icmp_glue_bits, icmp_param,
 			   icmp_param->data_len+icmp_param->head_len,
 			   icmp_param->head_len,
@@ -452,7 +443,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
 	if (IS_ERR(rt))
 		goto out_unlock;
 	if (icmpv4_xrlim_allow(net, rt, &fl4, type, code))
-		icmp_push_reply(icmp_param, &fl4, &ipc, &rt);
+		icmp_push_reply(sk, icmp_param, &fl4, &ipc, &rt);
 	ip_rt_put(rt);
 out_unlock:
 	icmp_xmit_unlock(sk);
@@ -766,7 +757,7 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
 	if (!fl4.saddr)
 		fl4.saddr = htonl(INADDR_DUMMY);
 
-	icmp_push_reply(&icmp_param, &fl4, &ipc, &rt);
+	icmp_push_reply(sk, &icmp_param, &fl4, &ipc, &rt);
 ende:
 	ip_rt_put(rt);
 out_unlock:
@@ -1434,46 +1425,8 @@ static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = {
 	},
 };
 
-static void __net_exit icmp_sk_exit(struct net *net)
-{
-	int i;
-
-	for_each_possible_cpu(i)
-		inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.icmp_sk, i));
-	free_percpu(net->ipv4.icmp_sk);
-	net->ipv4.icmp_sk = NULL;
-}
-
 static int __net_init icmp_sk_init(struct net *net)
 {
-	int i, err;
-
-	net->ipv4.icmp_sk = alloc_percpu(struct sock *);
-	if (!net->ipv4.icmp_sk)
-		return -ENOMEM;
-
-	for_each_possible_cpu(i) {
-		struct sock *sk;
-
-		err = inet_ctl_sock_create(&sk, PF_INET,
-					   SOCK_RAW, IPPROTO_ICMP, net);
-		if (err < 0)
-			goto fail;
-
-		*per_cpu_ptr(net->ipv4.icmp_sk, i) = sk;
-
-		/* Enough space for 2 64K ICMP packets, including
-		 * sk_buff/skb_shared_info struct overhead.
-		 */
-		sk->sk_sndbuf =	2 * SKB_TRUESIZE(64 * 1024);
-
-		/*
-		 * Speedup sock_wfree()
-		 */
-		sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
-		inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
-	}
-
 	/* Control parameters for ECHO replies. */
 	net->ipv4.sysctl_icmp_echo_ignore_all = 0;
 	net->ipv4.sysctl_icmp_echo_enable_probe = 0;
@@ -1499,18 +1452,36 @@ static int __net_init icmp_sk_init(struct net *net)
 	net->ipv4.sysctl_icmp_errors_use_inbound_ifaddr = 0;
 
 	return 0;
-
-fail:
-	icmp_sk_exit(net);
-	return err;
 }
 
 static struct pernet_operations __net_initdata icmp_sk_ops = {
        .init = icmp_sk_init,
-       .exit = icmp_sk_exit,
 };
 
 int __init icmp_init(void)
 {
+	int err, i;
+
+	for_each_possible_cpu(i) {
+		struct sock *sk;
+
+		err = inet_ctl_sock_create(&sk, PF_INET,
+					   SOCK_RAW, IPPROTO_ICMP, &init_net);
+		if (err < 0)
+			return err;
+
+		per_cpu(ipv4_icmp_sk, i) = sk;
+
+		/* Enough space for 2 64K ICMP packets, including
+		 * sk_buff/skb_shared_info struct overhead.
+		 */
+		sk->sk_sndbuf =	2 * SKB_TRUESIZE(64 * 1024);
+
+		/*
+		 * Speedup sock_wfree()
+		 */
+		sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
+		inet_sk(sk)->pmtudisc = IP_PMTUDISC_DONT;
+	}
 	return register_pernet_subsys(&icmp_sk_ops);
 }

net/ipv4/inet_timewait_sock.c

@@ -52,8 +52,7 @@ static void inet_twsk_kill(struct inet_timewait_sock *tw)
 	spin_unlock(lock);
 
 	/* Disassociate with bind bucket. */
-	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num,
-			hashinfo->bhash_size)];
+	bhead = &hashinfo->bhash[tw->tw_bslot];
 
 	spin_lock(&bhead->lock);
 	inet_twsk_bind_unhash(tw, hashinfo);
@@ -110,8 +109,12 @@ void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 	   Note, that any socket with inet->num != 0 MUST be bound in
 	   binding cache, even if it is closed.
 	 */
-	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num,
-			hashinfo->bhash_size)];
+	/* Cache inet_bhashfn(), because 'struct net' might be no longer
+	 * available later in inet_twsk_kill().
+	 */
+	tw->tw_bslot = inet_bhashfn(twsk_net(tw), inet->inet_num,
+				    hashinfo->bhash_size);
+	bhead = &hashinfo->bhash[tw->tw_bslot];
 	spin_lock(&bhead->lock);
 	tw->tw_tb = icsk->icsk_bind_hash;
 	WARN_ON(!icsk->icsk_bind_hash);
@@ -145,10 +148,6 @@ static void tw_timer_handler(struct timer_list *t)
 {
 	struct inet_timewait_sock *tw = from_timer(tw, t, tw_timer);
 
-	if (tw->tw_kill)
-		__NET_INC_STATS(twsk_net(tw), LINUX_MIB_TIMEWAITKILLED);
-	else
-		__NET_INC_STATS(twsk_net(tw), LINUX_MIB_TIMEWAITED);
 	inet_twsk_kill(tw);
 }
 
@@ -244,8 +243,11 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
 	 * of PAWS.
 	 */
 
-	tw->tw_kill = timeo <= 4*HZ;
 	if (!rearm) {
+		bool kill = timeo <= 4*HZ;
+
+		__NET_INC_STATS(twsk_net(tw), kill ? LINUX_MIB_TIMEWAITKILLED :
+						     LINUX_MIB_TIMEWAITED);
 		BUG_ON(mod_timer(&tw->tw_timer, jiffies + timeo));
 		atomic_inc(&tw->tw_dr->tw_count);
 	} else {
@@ -253,50 +255,3 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
 	}
 }
 EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
-
-void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
-{
-	struct inet_timewait_sock *tw;
-	struct sock *sk;
-	struct hlist_nulls_node *node;
-	unsigned int slot;
-
-	for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
-		struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
-restart_rcu:
-		cond_resched();
-		rcu_read_lock();
-restart:
-		sk_nulls_for_each_rcu(sk, node, &head->chain) {
-			if (sk->sk_state != TCP_TIME_WAIT)
-				continue;
-			tw = inet_twsk(sk);
-			if ((tw->tw_family != family) ||
-				refcount_read(&twsk_net(tw)->ns.count))
-				continue;
-
-			if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))
-				continue;
-
-			if (unlikely((tw->tw_family != family) ||
-				     refcount_read(&twsk_net(tw)->ns.count))) {
-				inet_twsk_put(tw);
-				goto restart;
-			}
-
-			rcu_read_unlock();
-			local_bh_disable();
-			inet_twsk_deschedule_put(tw);
-			local_bh_enable();
-			goto restart_rcu;
-		}
-		/* If the nulls value we got at the end of this lookup is
-		 * not the expected one, we must restart lookup.
-		 * We probably met an item that was moved to another chain.
-		 */
-		if (get_nulls_value(node) != slot)
-			goto restart;
-		rcu_read_unlock();
-	}
-}
-EXPORT_SYMBOL_GPL(inet_twsk_purge);

net/ipv4/tcp_ipv4.c

@@ -91,6 +91,8 @@ static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
 struct inet_hashinfo tcp_hashinfo;
 EXPORT_SYMBOL(tcp_hashinfo);
 
+static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
+
 static u32 tcp_v4_init_seq(const struct sk_buff *skb)
 {
 	return secure_tcp_seq(ip_hdr(skb)->daddr,
@@ -810,7 +812,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 	arg.tos = ip_hdr(skb)->tos;
 	arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
 	local_bh_disable();
-	ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
+	ctl_sk = this_cpu_read(ipv4_tcp_sk);
+	sock_net_set(ctl_sk, net);
 	if (sk) {
 		ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
 				   inet_twsk(sk)->tw_mark : sk->sk_mark;
@@ -825,6 +828,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
 			      transmit_time);
 
 	ctl_sk->sk_mark = 0;
+	sock_net_set(ctl_sk, &init_net);
 	__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 	__TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
 	local_bh_enable();
@@ -908,7 +912,8 @@ static void tcp_v4_send_ack(const struct sock *sk,
 	arg.tos = tos;
 	arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
 	local_bh_disable();
-	ctl_sk = this_cpu_read(*net->ipv4.tcp_sk);
+	ctl_sk = this_cpu_read(ipv4_tcp_sk);
+	sock_net_set(ctl_sk, net);
 	ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
 			   inet_twsk(sk)->tw_mark : sk->sk_mark;
 	ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?
@@ -921,6 +926,7 @@ static void tcp_v4_send_ack(const struct sock *sk,
 			      transmit_time);
 
 	ctl_sk->sk_mark = 0;
+	sock_net_set(ctl_sk, &init_net);
 	__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
 	local_bh_enable();
 }
@@ -3111,41 +3117,14 @@ EXPORT_SYMBOL(tcp_prot);
 
 static void __net_exit tcp_sk_exit(struct net *net)
 {
-	int cpu;
-
 	if (net->ipv4.tcp_congestion_control)
 		bpf_module_put(net->ipv4.tcp_congestion_control,
 			       net->ipv4.tcp_congestion_control->owner);
-
-	for_each_possible_cpu(cpu)
-		inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
-	free_percpu(net->ipv4.tcp_sk);
 }
 
 static int __net_init tcp_sk_init(struct net *net)
 {
-	int res, cpu, cnt;
-
-	net->ipv4.tcp_sk = alloc_percpu(struct sock *);
-	if (!net->ipv4.tcp_sk)
-		return -ENOMEM;
-
-	for_each_possible_cpu(cpu) {
-		struct sock *sk;
-
-		res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
-					   IPPROTO_TCP, net);
-		if (res)
-			goto fail;
-		sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
-
-		/* Please enforce IP_DF and IPID==0 for RST and
-		 * ACK sent in SYN-RECV and TIME-WAIT state.
-		 */
-		inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
-
-		*per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk;
-	}
+	int cnt;
 
 	net->ipv4.sysctl_tcp_ecn = 2;
 	net->ipv4.sysctl_tcp_ecn_fallback = 1;
@@ -3229,18 +3208,12 @@ static int __net_init tcp_sk_init(struct net *net)
 		net->ipv4.tcp_congestion_control = &tcp_reno;
 
 	return 0;
-fail:
-	tcp_sk_exit(net);
-
-	return res;
 }
 
 static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
 {
 	struct net *net;
 
-	inet_twsk_purge(&tcp_hashinfo, AF_INET);
-
 	list_for_each_entry(net, net_exit_list, exit_list)
 		tcp_fastopen_ctx_destroy(net);
 }
@@ -3326,6 +3299,24 @@ static void __init bpf_iter_register(void)
 
 void __init tcp_v4_init(void)
 {
+	int cpu, res;
+
+	for_each_possible_cpu(cpu) {
+		struct sock *sk;
+
+		res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW,
+					   IPPROTO_TCP, &init_net);
+		if (res)
+			panic("Failed to create the TCP control socket.\n");
+		sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
+
+		/* Please enforce IP_DF and IPID==0 for RST and
+		 * ACK sent in SYN-RECV and TIME-WAIT state.
+		 */
+		inet_sk(sk)->pmtudisc = IP_PMTUDISC_DO;
+
+		per_cpu(ipv4_tcp_sk, cpu) = sk;
+	}
 	if (register_pernet_subsys(&tcp_sk_ops))
 		panic("Failed to create the TCP control socket.\n");
 

net/ipv6/icmp.c

@@ -69,17 +69,7 @@
 
 #include <linux/uaccess.h>
 
-/*
- *	The ICMP socket(s). This is the most convenient way to flow control
- *	our ICMP output as well as maintain a clean interface throughout
- *	all layers. All Socketless IP sends will soon be gone.
- *
- *	On SMP we have one ICMP socket per-cpu.
- */
-static struct sock *icmpv6_sk(struct net *net)
-{
-	return this_cpu_read(*net->ipv6.icmp_sk);
-}
+static DEFINE_PER_CPU(struct sock *, ipv6_icmp_sk);
 
 static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		       u8 type, u8 code, int offset, __be32 info)
@@ -110,11 +100,11 @@ static const struct inet6_protocol icmpv6_protocol = {
 };
 
 /* Called with BH disabled */
-static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
+static struct sock *icmpv6_xmit_lock(struct net *net)
 {
 	struct sock *sk;
 
-	sk = icmpv6_sk(net);
+	sk = this_cpu_read(ipv6_icmp_sk);
 	if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
 		/* This can happen if the output path (f.e. SIT or
 		 * ip6ip6 tunnel) signals dst_link_failure() for an
@@ -122,11 +112,13 @@ static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
 		 */
 		return NULL;
 	}
+	sock_net_set(sk, net);
 	return sk;
 }
 
-static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
+static void icmpv6_xmit_unlock(struct sock *sk)
 {
+	sock_net_set(sk, &init_net);
 	spin_unlock(&sk->sk_lock.slock);
 }
 
@@ -1034,59 +1026,27 @@ void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
 	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
 }
 
-static void __net_exit icmpv6_sk_exit(struct net *net)
-{
-	int i;
-
-	for_each_possible_cpu(i)
-		inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i));
-	free_percpu(net->ipv6.icmp_sk);
-}
-
-static int __net_init icmpv6_sk_init(struct net *net)
+int __init icmpv6_init(void)
 {
 	struct sock *sk;
 	int err, i;
 
-	net->ipv6.icmp_sk = alloc_percpu(struct sock *);
-	if (!net->ipv6.icmp_sk)
-		return -ENOMEM;
-
 	for_each_possible_cpu(i) {
 		err = inet_ctl_sock_create(&sk, PF_INET6,
-					   SOCK_RAW, IPPROTO_ICMPV6, net);
+					   SOCK_RAW, IPPROTO_ICMPV6, &init_net);
 		if (err < 0) {
 			pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
 			       err);
-			goto fail;
+			return err;
 		}
 
-		*per_cpu_ptr(net->ipv6.icmp_sk, i) = sk;
+		per_cpu(ipv6_icmp_sk, i) = sk;
 
 		/* Enough space for 2 64K ICMP packets, including
 		 * sk_buff struct overhead.
 		 */
 		sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
 	}
-	return 0;
-
- fail:
-	icmpv6_sk_exit(net);
-	return err;
-}
-
-static struct pernet_operations icmpv6_sk_ops = {
-	.init = icmpv6_sk_init,
-	.exit = icmpv6_sk_exit,
-};
-
-int __init icmpv6_init(void)
-{
-	int err;
-
-	err = register_pernet_subsys(&icmpv6_sk_ops);
-	if (err < 0)
-		return err;
 
 	err = -EAGAIN;
 	if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
@@ -1101,14 +1061,12 @@ int __init icmpv6_init(void)
 	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 fail:
 	pr_err("Failed to register ICMP6 protocol\n");
-	unregister_pernet_subsys(&icmpv6_sk_ops);
 	return err;
 }
 
 void icmpv6_cleanup(void)
 {
 	inet6_unregister_icmp_sender(icmp6_send);
-	unregister_pernet_subsys(&icmpv6_sk_ops);
 	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 }
 

net/ipv6/tcp_ipv6.c

@@ -2237,15 +2237,9 @@ static void __net_exit tcpv6_net_exit(struct net *net)
 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
 }
 
-static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
-{
-	inet_twsk_purge(&tcp_hashinfo, AF_INET6);
-}
-
 static struct pernet_operations tcpv6_net_ops = {
 	.init	    = tcpv6_net_init,
 	.exit	    = tcpv6_net_exit,
-	.exit_batch = tcpv6_net_exit_batch,
 };
 
 int __init tcpv6_init(void)