Re: [PATCH 1/4] ipv6: add a new namespace for nf_conntrack_reasm

As pointed by Michal, it is necessary to add a new
namespace for nf_conntrack_reasm code, this prepares
for the second patch.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Michal Kubeček <redacted>
Cc: David Miller <davem@davemloft.net>
Cc: Patrick McHardy <redacted>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Signed-off-by: Cong Wang <redacted>
---
 include/net/net_namespace.h             |    3 +
 include/net/netns/ipv6.h                |    8 ++
 net/ipv6/netfilter/nf_conntrack_reasm.c |  135 +++++++++++++++++++++----------
 3 files changed, 104 insertions(+), 42 deletions(-)

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 5ae57f1..d61e2b3 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h

@@ -93,6 +93,9 @@ struct net {
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 	struct netns_ct		ct;
 #endif
+#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
+	struct netns_nf_frag	nf_frag;
+#endif
 	struct sock		*nfnl;
 	struct sock		*nfnl_stash;
 #endif

diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 0318104..214cb0a 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h

@@ -71,4 +71,12 @@ struct netns_ipv6 {
 #endif
 #endif
 };
+
+#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
+struct netns_nf_frag {
+	struct netns_sysctl_ipv6 sysctl;
+	struct netns_frags	frags;
+};
+#endif
+
 #endif

diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index f94fb3a..d28c067 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c

@@ -71,27 +71,26 @@ struct nf_ct_frag6_queue
 };
 
 static struct inet_frags nf_frags;
-static struct netns_frags nf_init_frags;
 
 #ifdef CONFIG_SYSCTL
 static struct ctl_table nf_ct_frag6_sysctl_table[] = {
 	{
 		.procname	= "nf_conntrack_frag6_timeout",
-		.data		= &nf_init_frags.timeout,
+		.data		= &init_net.nf_frag.frags.timeout,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
 	{
 		.procname	= "nf_conntrack_frag6_low_thresh",
-		.data		= &nf_init_frags.low_thresh,
+		.data		= &init_net.nf_frag.frags.low_thresh,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
 	{
 		.procname	= "nf_conntrack_frag6_high_thresh",
-		.data		= &nf_init_frags.high_thresh,
+		.data		= &init_net.nf_frag.frags.high_thresh,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,

@@ -99,7 +98,54 @@ static struct ctl_table nf_ct_frag6_sysctl_table[] = {
 	{ }
 };
 
-static struct ctl_table_header *nf_ct_frag6_sysctl_header;
+static int __net_init nf_ct_frag6_sysctl_register(struct net *net)
+{
+	struct ctl_table *table;
+	struct ctl_table_header *hdr;
+
+	table = nf_ct_frag6_sysctl_table;
+	if (!net_eq(net, &init_net)) {
+		table = kmemdup(table, sizeof(nf_ct_frag6_sysctl_table), GFP_KERNEL);