neighbour: Remove neigh_tables[].

Now, &arp_tbl and &nd_tbl are stored in net->neigh_tables[].

Let's use net->neigh_tables[] in neighbour.c and remove the
global neigh_tables[].

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260902203722.926528-8-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 20 insertions, 24 deletions

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 700d62605fab..3e31eebf8663 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -341,8 +341,8 @@ 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(int index, struct neigh_table *tbl);
-int neigh_table_clear(int index, struct neigh_table *tbl);
+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 286acb7cd504..34da4cdc813d 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1807,9 +1807,7 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms)
 
 static struct lock_class_key neigh_table_proxy_queue_class;
 
-static struct neigh_table *neigh_tables[NEIGH_NR_TABLES] __read_mostly;
-
-void neigh_table_init(int index, struct neigh_table *tbl)
+void neigh_table_init(struct neigh_table *tbl)
 {
 	unsigned long now = jiffies;
 	unsigned long phsize;
@@ -1863,18 +1861,14 @@ void neigh_table_init(int index, struct neigh_table *tbl)
 
 	tbl->last_flush = now;
 	tbl->last_rand	= now + tbl->parms.reachable_time * 20;
-
-	neigh_tables[index] = tbl;
 }
 
 /*
  * Only called from ndisc_cleanup(), which means this is dead code
  * because we no longer can unload IPv6 module.
  */
-int neigh_table_clear(int index, struct neigh_table *tbl)
+int neigh_table_clear(struct neigh_table *tbl)
 {
-	neigh_tables[index] = NULL;
-
 	/* It is not clean... Fix it to unload IPv6 module safely */
 	cancel_delayed_work_sync(&tbl->managed_work);
 	cancel_delayed_work_sync(&tbl->gc_work);
@@ -1911,16 +1905,16 @@ void neigh_table_unregister(struct net *net, int index)
 	net->neigh_tables[index] = NULL;
 }
 
-static struct neigh_table *neigh_find_table(int family)
+static struct neigh_table *neigh_find_table(struct net *net, int family)
 {
 	struct neigh_table *tbl = NULL;
 
 	switch (family) {
 	case AF_INET:
-		tbl = neigh_tables[NEIGH_ARP_TABLE];
+		tbl = net->neigh_tables[NEIGH_ARP_TABLE];
 		break;
 	case AF_INET6:
-		tbl = neigh_tables[NEIGH_ND_TABLE];
+		tbl = net->neigh_tables[NEIGH_ND_TABLE];
 		break;
 	}
 
@@ -1974,7 +1968,7 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh,
 		}
 	}
 
-	tbl = neigh_find_table(ndm->ndm_family);
+	tbl = neigh_find_table(net, ndm->ndm_family);
 	if (tbl == NULL)
 		return -EAFNOSUPPORT;
 
@@ -2060,7 +2054,7 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 		}
 	}
 
-	tbl = neigh_find_table(ndm->ndm_family);
+	tbl = neigh_find_table(net, ndm->ndm_family);
 	if (tbl == NULL)
 		return -EAFNOSUPPORT;
 
@@ -2403,7 +2397,7 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh,
 	ndtmsg = nlmsg_data(nlh);
 
 	for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
-		tbl = neigh_tables[tidx];
+		tbl = net->neigh_tables[tidx];
 		if (!tbl)
 			continue;
 
@@ -2596,7 +2590,7 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 	for (tidx = 0; tidx < NEIGH_NR_TABLES; tidx++) {
 		struct neigh_parms *p;
 
-		tbl = neigh_tables[tidx];
+		tbl = net->neigh_tables[tidx];
 		if (!tbl)
 			continue;
 
@@ -2933,6 +2927,7 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	const struct nlmsghdr *nlh = cb->nlh;
 	struct neigh_dump_filter filter = {};
+	struct net *net = sock_net(skb->sk);
 	struct neigh_table *tbl;
 	int t, family, s_t;
 	int proxy = 0;
@@ -2956,8 +2951,7 @@ static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 
 	rcu_read_lock();
 	for (t = 0; t < NEIGH_NR_TABLES; t++) {
-		tbl = neigh_tables[t];
-
+		tbl = net->neigh_tables[t];
 		if (!tbl)
 			continue;
 		if (t < s_t || (family && tbl->family != family))
@@ -3079,7 +3073,7 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 
 	rcu_read_lock();
 
-	tbl = neigh_find_table(ndm->ndm_family);
+	tbl = neigh_find_table(net, ndm->ndm_family);
 	if (!tbl) {
 		NL_SET_ERR_MSG(extack, "Unsupported family in header for neighbor get request");
 		err = -EAFNOSUPPORT;
@@ -3167,9 +3161,11 @@ int neigh_xmit(int index, struct net_device *dev,
 	if (likely(index < NEIGH_NR_TABLES)) {
 		struct neigh_table *tbl;
 		struct neighbour *neigh;
+		struct net *net;
 
 		rcu_read_lock();
-		tbl = neigh_tables[index];
+		net = dev_net_rcu(dev);
+		tbl = net->neigh_tables[index];
 		if (!tbl) {
 			rcu_read_unlock();
 			goto out_kfree_skb;
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index bad17d5aeafc..824c65c70408 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -1532,7 +1532,7 @@ static struct pernet_operations arp_net_ops = {
 
 void __init arp_init(void)
 {
-	neigh_table_init(NEIGH_ARP_TABLE, &arp_tbl);
+	neigh_table_init(&arp_tbl);
 
 	dev_add_pack(&arp_packet_type);
 	register_pernet_subsys(&arp_net_ops);
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index dc4c083fe27a..ed07cf78d223 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -2022,7 +2022,7 @@ int __init ndisc_init(void)
 	/*
 	 * Initialize the neighbour table
 	 */
-	neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
+	neigh_table_init(&nd_tbl);
 
 #ifdef CONFIG_SYSCTL
 	err = neigh_sysctl_register(NULL, &nd_tbl.parms,
@@ -2055,6 +2055,6 @@ void ndisc_cleanup(void)
 #ifdef CONFIG_SYSCTL
 	neigh_sysctl_unregister(&nd_tbl.parms);
 #endif
-	neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl);
+	neigh_table_clear(&nd_tbl);
 	unregister_pernet_subsys(&ndisc_net_ops);
 }