[PATCH v2 net-next 10/13] neighbour: Namespacify neigh_tables.

[Kuniyuki Iwashima <kuniyu@google.com>]

Now, neigh_table is ready to be namespacified.

Let's allocate per-netns neigh_table in neigh_table_register()
and call neigh_table_init() and neigh_sysctl_register() for it.

proc_create_seq_data() is changed to proc_create_net_data().

neigh_flush_one() calls timer_shutdown_sync() outside of n->lock
if its netns is dying because neigh_del_timer() uses timer_delete()
and there might be running timer and its neigh_release() might
be executed after neigh_table_clear() frees neigh_table.

The next patch will remove other unnecessary net_eq().

Note that CONFIG_SYSCTL cannot be enabled without CONFIG_PROC_FS.

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
v2:
  * panic() when register_pernet_subsys(&arp_net_ops) fails
  * Add timer_shutdown_sync() in neigh_flush_one()
---
 include/net/neighbour.h |  2 --
 net/core/neighbour.c    | 45 ++++++++++++++++++++++++++++-------------
 net/ipv4/arp.c          | 20 +++++++++++++-----
 net/ipv6/ndisc.c        | 43 ++++++++++++++-------------------------
 4 files changed, 61 insertions(+), 49 deletions(-)

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 3e31eebf8663..b4e89533e1e6 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -341,8 +341,6 @@ static inline void neigh_confirm(struct neighbour *n)
 
 int neigh_table_register(struct net *net, struct neigh_table *tbl, int index);
 void neigh_table_unregister(struct net *net, int index);
-void neigh_table_init(struct neigh_table *tbl);
-int neigh_table_clear(struct neigh_table *tbl);
 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
 			       struct net_device *dev);
 struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 36488dbd1512..71aadcf9626d 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -397,6 +397,9 @@ static void neigh_flush_one(struct neighbour *n)
 
 	write_unlock(&n->lock);
 
+	if (!check_net(neigh_parms_net(n->parms)))
+		timer_shutdown_sync(&n->timer);
+
 	neigh_cleanup_and_release(n);
 }
 
@@ -1807,10 +1810,9 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
 
 static struct lock_class_key neigh_table_proxy_queue_class;
 
-void neigh_table_init(struct neigh_table *tbl)
+static int neigh_table_init(struct net *net, struct neigh_table *tbl)
 {
 	unsigned long now = jiffies;
-	struct net *net = &init_net;
 	unsigned long phsize;
 
 	RCU_INIT_POINTER(tbl->nht, neigh_hash_alloc(3));
@@ -1830,8 +1832,9 @@ void neigh_table_init(struct neigh_table *tbl)
 		goto err_stats;
 
 #ifdef CONFIG_PROC_FS
-	if (!proc_create_seq_data(tbl->id, 0, net->proc_net_stat,
-				  &neigh_stat_seq_ops, tbl))
+	if (!proc_create_net_data(tbl->id, 0, net->proc_net_stat,
+				  &neigh_stat_seq_ops,
+				  sizeof(struct seq_net_private), tbl))
 		goto err_proc;
 #endif
 
@@ -1860,7 +1863,7 @@ void neigh_table_init(struct neigh_table *tbl)
 	INIT_DEFERRABLE_WORK(&tbl->managed_work, neigh_managed_work);
 	queue_delayed_work(system_power_efficient_wq, &tbl->managed_work, 0);
 
-	return;
+	return 0;
 
 #ifdef CONFIG_PROC_FS
 err_proc:
@@ -1871,16 +1874,11 @@ void neigh_table_init(struct neigh_table *tbl)
 err_phash:
 	neigh_hash_free_rcu(&rcu_dereference_protected(tbl->nht, 1)->rcu);
 err_hash:
-	panic("cannot allocate memory");
+	return -ENOMEM;
 }
 
-/*
- * Only called from ndisc_cleanup(), which means this is dead code
- * because we no longer can unload IPv6 module.
- */
-int neigh_table_clear(struct neigh_table *tbl)
+static void neigh_table_clear(struct net *net, struct neigh_table *tbl)
 {
-	struct net *net __maybe_unused = &init_net;
 	struct neigh_hash_table *nht;
 
 	cancel_delayed_work_sync(&tbl->managed_work);
@@ -1901,20 +1899,39 @@ int neigh_table_clear(struct neigh_table *tbl)
 	nht = rcu_dereference_protected(tbl->nht, 1);
 	tbl->nht = NULL;
 	neigh_hash_free_rcu(&nht->rcu);
-
-	return 0;
 }
 
 int neigh_table_register(struct net *net, struct neigh_table *tbl, int index)
 {
+	int err;
+
+	tbl = kmemdup(tbl, sizeof(*tbl), GFP_KERNEL);
+	if (!tbl) {
+		err = -ENOMEM;
+		goto err;
+	}
+
+	err = neigh_table_init(net, tbl);
+	if (err)
+		goto free_table;
+
 	net->neigh_tables[index] = tbl;
 
 	return 0;
+
+free_table:
+	kfree(tbl);
+err:
+	return err;
 }
 
 void neigh_table_unregister(struct net *net, int index)
 {
+	struct neigh_table *tbl = net->neigh_tables[index];
+
 	net->neigh_tables[index] = NULL;
+	neigh_table_clear(net, tbl);
+	kfree(tbl);
 }
 
 static struct neigh_table *neigh_find_table(struct net *net, int family)
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index a44fa68fdd07..f197051d3aa7 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -1518,6 +1518,12 @@ static int __net_init arp_net_init(struct net *net)
 		goto err;
 
 #ifdef CONFIG_PROC_FS
+#ifdef CONFIG_SYSCTL
+	err = neigh_sysctl_register(NULL, &arp_table(net)->parms, NULL);
+	if (err)
+		goto err_sysctl;
+#endif
+
 	if (!proc_create_net("arp", 0444, net->proc_net, &arp_seq_ops,
 			     sizeof(struct neigh_seq_state))) {
 		err = -ENOMEM;
@@ -1529,6 +1535,10 @@ static int __net_init arp_net_init(struct net *net)
 
 #ifdef CONFIG_PROC_FS
 err_proc_create:
+#ifdef CONFIG_SYSCTL
+	neigh_sysctl_unregister(&arp_table(net)->parms);
+err_sysctl:
+#endif
 	neigh_table_unregister(net, NEIGH_ARP_TABLE);
 #endif
 err:
@@ -1538,6 +1548,9 @@ static int __net_init arp_net_init(struct net *net)
 static void __net_exit arp_net_exit(struct net *net)
 {
 	remove_proc_entry("arp", net->proc_net);
+#ifdef CONFIG_SYSCTL
+	neigh_sysctl_unregister(&arp_table(net)->parms);
+#endif
 	neigh_table_unregister(net, NEIGH_ARP_TABLE);
 }
 
@@ -1548,12 +1561,9 @@ static struct pernet_operations arp_net_ops = {
 
 void __init arp_init(void)
 {
-	neigh_table_init(&arp_tbl);
+	if (register_pernet_subsys(&arp_net_ops))
+		panic("Cannot allocate arp table\n");
 
 	dev_add_pack(&arp_packet_type);
-	register_pernet_subsys(&arp_net_ops);
-#ifdef CONFIG_SYSCTL
-	neigh_sysctl_register(NULL, &arp_tbl.parms, NULL);
-#endif
 	register_netdevice_notifier(&arp_netdev_notifier);
 }
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 3a458b188595..13e24c64dcdc 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1984,6 +1984,13 @@ static int __net_init ndisc_net_init(struct net *net)
 	if (err)
 		goto err;
 
+#ifdef CONFIG_SYSCTL
+	err = neigh_sysctl_register(NULL, &nd_table(net)->parms,
+				    ndisc_ifinfo_sysctl_change);
+	if (err)
+		goto err_sysctl;
+#endif
+
 	err = inet_ctl_sock_create(&sk, PF_INET6,
 				   SOCK_RAW, IPPROTO_ICMPV6, net);
 	if (err < 0) {
@@ -2002,6 +2009,10 @@ static int __net_init ndisc_net_init(struct net *net)
 	return 0;
 
 err_sock_create:
+#ifdef CONFIG_SYSCTL
+	neigh_sysctl_unregister(&nd_table(net)->parms);
+err_sysctl:
+#endif
 	neigh_table_unregister(net, NEIGH_ND_TABLE);
 err:
 	return err;
@@ -2010,6 +2021,9 @@ static int __net_init ndisc_net_init(struct net *net)
 static void __net_exit ndisc_net_exit(struct net *net)
 {
 	inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
+#ifdef CONFIG_SYSCTL
+	neigh_sysctl_unregister(&nd_table(net)->parms);
+#endif
 	neigh_table_unregister(net, NEIGH_ND_TABLE);
 }
 
@@ -2020,30 +2034,7 @@ static struct pernet_operations ndisc_net_ops = {
 
 int __init ndisc_init(void)
 {
-	int err;
-
-	err = register_pernet_subsys(&ndisc_net_ops);
-	if (err)
-		return err;
-	/*
-	 * Initialize the neighbour table
-	 */
-	neigh_table_init(&nd_tbl);
-
-#ifdef CONFIG_SYSCTL
-	err = neigh_sysctl_register(NULL, &nd_tbl.parms,
-				    ndisc_ifinfo_sysctl_change);
-	if (err)
-		goto out_unregister_pernet;
-out:
-#endif
-	return err;
-
-#ifdef CONFIG_SYSCTL
-out_unregister_pernet:
-	unregister_pernet_subsys(&ndisc_net_ops);
-	goto out;
-#endif
+	return register_pernet_subsys(&ndisc_net_ops);
 }
 
 int __init ndisc_late_init(void)
@@ -2058,9 +2049,5 @@ void ndisc_late_cleanup(void)
 
 void ndisc_cleanup(void)
 {
-#ifdef CONFIG_SYSCTL
-	neigh_sysctl_unregister(&nd_tbl.parms);
-#endif
-	neigh_table_clear(&nd_tbl);
 	unregister_pernet_subsys(&ndisc_net_ops);
 }
-- 
2.55.0.679.g6767b8d81c-goog