net: Convert pernet_subsys, registered from inet_init()

arp_net_ops just addr/removes /proc entry.

devinet_ops allocates and frees duplicate of init_net tables
and (un)registers sysctl entries.

fib_net_ops allocates and frees pernet tables, creates/destroys
netlink socket and (un)initializes /proc entries. Foreign
pernet_operations do not touch them.

ip_rt_proc_ops only modifies pernet /proc entries.

xfrm_net_ops creates/destroys /proc entries, allocates/frees
pernet statistics, hashes and tables, and (un)initializes
sysctl files. These are not touched by foreigh pernet_operations

xfrm4_net_ops allocates/frees private pernet memory, and
configures sysctls.

sysctl_route_ops creates/destroys sysctls.

rt_genid_ops only initializes fields of just allocated net.

ipv4_inetpeer_ops allocated/frees net private memory.

igmp_net_ops just creates/destroys /proc files and socket,
noone else interested in.

tcp_sk_ops seems to be safe, because tcp_sk_init() does not
depend on any other pernet_operations modifications. Iteration
over hash table in inet_twsk_purge() is made under RCU lock,
and it's safe to iterate the table this way. Removing from
the table happen from inet_twsk_deschedule_put(), but this
function is safe without any extern locks, as it's synchronized
inside itself. There are many examples, it's used in different
context. So, it's safe to leave tcp_sk_exit_batch() unlocked.

tcp_net_metrics_ops is synchronized on tcp_metrics_lock and safe.

udplite4_net_ops only creates/destroys pernet /proc file.

icmp_sk_ops creates percpu sockets, not touched by foreign
pernet_operations.

ipmr_net_ops creates/destroys pernet fib tables, (un)registers
fib rules and /proc files. This seem to be safe to execute
in parallel with foreign pernet_operations.

af_inet_ops just sets up default parameters of newly created net.

ipv4_mib_ops creates and destroys pernet percpu statistics.

raw_net_ops, tcp4_net_ops, udp4_net_ops, ping_v4_net_ops
and ip_proc_ops only create/destroy pernet /proc files.

ip4_frags_ops creates and destroys sysctl file.

So, it's safe to make the pernet_operations async.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/af_inet.c

@@ -1735,6 +1735,7 @@ static __net_exit void ipv4_mib_exit_net(struct net *net)
 static __net_initdata struct pernet_operations ipv4_mib_ops = {
 	.init = ipv4_mib_init_net,
 	.exit = ipv4_mib_exit_net,
+	.async = true,
 };
 
 static int __init init_ipv4_mibs(void)
@@ -1788,6 +1789,7 @@ static __net_exit void inet_exit_net(struct net *net)
 static __net_initdata struct pernet_operations af_inet_ops = {
 	.init = inet_init_net,
 	.exit = inet_exit_net,
+	.async = true,
 };
 
 static int __init init_inet_pernet_ops(void)

net/ipv4/arp.c

@@ -1447,6 +1447,7 @@ static void __net_exit arp_net_exit(struct net *net)
 static struct pernet_operations arp_net_ops = {
 	.init = arp_net_init,
 	.exit = arp_net_exit,
+	.async = true,
 };
 
 static int __init arp_proc_init(void)

net/ipv4/devinet.c

@@ -2469,6 +2469,7 @@ static __net_exit void devinet_exit_net(struct net *net)
 static __net_initdata struct pernet_operations devinet_ops = {
 	.init = devinet_init_net,
 	.exit = devinet_exit_net,
+	.async = true,
 };
 
 static struct rtnl_af_ops inet_af_ops __read_mostly = {

net/ipv4/fib_frontend.c

@@ -1362,6 +1362,7 @@ static void __net_exit fib_net_exit(struct net *net)
 static struct pernet_operations fib_net_ops = {
 	.init = fib_net_init,
 	.exit = fib_net_exit,
+	.async = true,
 };
 
 void __init ip_fib_init(void)

net/ipv4/icmp.c

@@ -1257,6 +1257,7 @@ static int __net_init icmp_sk_init(struct net *net)
 static struct pernet_operations __net_initdata icmp_sk_ops = {
        .init = icmp_sk_init,
        .exit = icmp_sk_exit,
+       .async = true,
 };
 
 int __init icmp_init(void)

net/ipv4/igmp.c

@@ -3028,6 +3028,7 @@ static void __net_exit igmp_net_exit(struct net *net)
 static struct pernet_operations igmp_net_ops = {
 	.init = igmp_net_init,
 	.exit = igmp_net_exit,
+	.async = true,
 };
 #endif
 

net/ipv4/ip_fragment.c

@@ -885,6 +885,7 @@ static void __net_exit ipv4_frags_exit_net(struct net *net)
 static struct pernet_operations ip4_frags_ops = {
 	.init = ipv4_frags_init_net,
 	.exit = ipv4_frags_exit_net,
+	.async = true,
 };
 
 void __init ipfrag_init(void)

net/ipv4/ipmr.c

@@ -3327,6 +3327,7 @@ static void __net_exit ipmr_net_exit(struct net *net)
 static struct pernet_operations ipmr_net_ops = {
 	.init = ipmr_net_init,
 	.exit = ipmr_net_exit,
+	.async = true,
 };
 
 int __init ip_mr_init(void)

net/ipv4/ping.c

@@ -1204,6 +1204,7 @@ static void __net_exit ping_v4_proc_exit_net(struct net *net)
 static struct pernet_operations ping_v4_net_ops = {
 	.init = ping_v4_proc_init_net,
 	.exit = ping_v4_proc_exit_net,
+	.async = true,
 };
 
 int __init ping_proc_init(void)

net/ipv4/proc.c

@@ -549,6 +549,7 @@ static __net_exit void ip_proc_exit_net(struct net *net)
 static __net_initdata struct pernet_operations ip_proc_ops = {
 	.init = ip_proc_init_net,
 	.exit = ip_proc_exit_net,
+	.async = true,
 };
 
 int __init ip_misc_proc_init(void)

net/ipv4/raw.c

@@ -1156,6 +1156,7 @@ static __net_exit void raw_exit_net(struct net *net)
 static __net_initdata struct pernet_operations raw_net_ops = {
 	.init = raw_init_net,
 	.exit = raw_exit_net,
+	.async = true,
 };
 
 int __init raw_proc_init(void)

net/ipv4/route.c

@@ -417,6 +417,7 @@ static void __net_exit ip_rt_do_proc_exit(struct net *net)
 static struct pernet_operations ip_rt_proc_ops __net_initdata =  {
 	.init = ip_rt_do_proc_init,
 	.exit = ip_rt_do_proc_exit,
+	.async = true,
 };
 
 static int __init ip_rt_proc_init(void)
@@ -2994,6 +2995,7 @@ static __net_exit void sysctl_route_net_exit(struct net *net)
 static __net_initdata struct pernet_operations sysctl_route_ops = {
 	.init = sysctl_route_net_init,
 	.exit = sysctl_route_net_exit,
+	.async = true,
 };
 #endif
 
@@ -3007,6 +3009,7 @@ static __net_init int rt_genid_init(struct net *net)
 
 static __net_initdata struct pernet_operations rt_genid_ops = {
 	.init = rt_genid_init,
+	.async = true,
 };
 
 static int __net_init ipv4_inetpeer_init(struct net *net)
@@ -3032,6 +3035,7 @@ static void __net_exit ipv4_inetpeer_exit(struct net *net)
 static __net_initdata struct pernet_operations ipv4_inetpeer_ops = {
 	.init	=	ipv4_inetpeer_init,
 	.exit	=	ipv4_inetpeer_exit,
+	.async	=	true,
 };
 
 #ifdef CONFIG_IP_ROUTE_CLASSID

net/ipv4/tcp_ipv4.c

@@ -2387,6 +2387,7 @@ static void __net_exit tcp4_proc_exit_net(struct net *net)
 static struct pernet_operations tcp4_net_ops = {
 	.init = tcp4_proc_init_net,
 	.exit = tcp4_proc_exit_net,
+	.async = true,
 };
 
 int __init tcp4_proc_init(void)
@@ -2573,6 +2574,7 @@ static struct pernet_operations __net_initdata tcp_sk_ops = {
        .init	   = tcp_sk_init,
        .exit	   = tcp_sk_exit,
        .exit_batch = tcp_sk_exit_batch,
+       .async	   = true,
 };
 
 void __init tcp_v4_init(void)

net/ipv4/tcp_metrics.c

@@ -1024,6 +1024,7 @@ static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_lis
 static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
 	.init		=	tcp_net_metrics_init,
 	.exit_batch	=	tcp_net_metrics_exit_batch,
+	.async		=	true,
 };
 
 void __init tcp_metrics_init(void)

net/ipv4/udp.c

@@ -2757,6 +2757,7 @@ static void __net_exit udp4_proc_exit_net(struct net *net)
 static struct pernet_operations udp4_net_ops = {
 	.init = udp4_proc_init_net,
 	.exit = udp4_proc_exit_net,
+	.async = true,
 };
 
 int __init udp4_proc_init(void)

net/ipv4/udplite.c

@@ -104,6 +104,7 @@ static void __net_exit udplite4_proc_exit_net(struct net *net)
 static struct pernet_operations udplite4_net_ops = {
 	.init = udplite4_proc_init_net,
 	.exit = udplite4_proc_exit_net,
+	.async = true,
 };
 
 static __init int udplite4_proc_init(void)

net/ipv4/xfrm4_policy.c

@@ -365,6 +365,7 @@ static void __net_exit xfrm4_net_exit(struct net *net)
 static struct pernet_operations __net_initdata xfrm4_net_ops = {
 	.init	= xfrm4_net_init,
 	.exit	= xfrm4_net_exit,
+	.async	= true,
 };
 
 static void __init xfrm4_policy_init(void)

net/xfrm/xfrm_policy.c

@@ -2982,6 +2982,7 @@ static void __net_exit xfrm_net_exit(struct net *net)
 static struct pernet_operations __net_initdata xfrm_net_ops = {
 	.init = xfrm_net_init,
 	.exit = xfrm_net_exit,
+	.async = true,
 };
 
 void __init xfrm_init(void)