Merge branch 'net-bridge-convert-multicast-to-generic-rhashtable'

Nikolay Aleksandrov says:

====================
net: bridge: convert multicast to generic rhashtable

The current bridge multicast code uses a custom rhashtable
implementation which predates the generic rhashtable API. Patch 01
converts it to use the generic kernel rhashtable which simplifies the
code a lot and removes duplicated functionality. The convert also makes
hash_elasticity obsolete as the generic rhashtable already has such
checks and has a fixed elasticity of RHT_ELASTICITY (16 currently) so we
emit a warning whenever elasticity is set and return RHT_ELASTICITY when
read (patch 03). Patch 02 converts the multicast code to use non-bh RCU
flavor as it was mixing bh and non-bh. Since now we have the generic
rhashtable which autoshrinks we can be more liberal with the default
hash maximum so patch 04 increases it to 4096 and moves it to a define in
br_private.h.

v3: add non-rcu br_mdb_get variant and use it where we have
    multicast_lock, drop special hash_max handling and just set it where
    needed and use non-bh RCU consistently (patch 02, new)
v2: send the latest version of the set which handles when IGMP snooping
    is not defined, changes are in patch 01
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_device.c

@@ -131,9 +131,17 @@ static int br_dev_init(struct net_device *dev)
 		return err;
 	}
 
+	err = br_mdb_hash_init(br);
+	if (err) {
+		free_percpu(br->stats);
+		br_fdb_hash_fini(br);
+		return err;
+	}
+
 	err = br_vlan_init(br);
 	if (err) {
 		free_percpu(br->stats);
+		br_mdb_hash_fini(br);
 		br_fdb_hash_fini(br);
 		return err;
 	}
@@ -142,6 +150,7 @@ static int br_dev_init(struct net_device *dev)
 	if (err) {
 		free_percpu(br->stats);
 		br_vlan_flush(br);
+		br_mdb_hash_fini(br);
 		br_fdb_hash_fini(br);
 	}
 	br_set_lockdep_class(dev);
@@ -156,6 +165,7 @@ static void br_dev_uninit(struct net_device *dev)
 	br_multicast_dev_del(br);
 	br_multicast_uninit_stats(br);
 	br_vlan_flush(br);
+	br_mdb_hash_fini(br);
 	br_fdb_hash_fini(br);
 	free_percpu(br->stats);
 }

net/bridge/br_mdb.c

@@ -78,41 +78,33 @@ static void __mdb_entry_to_br_ip(struct br_mdb_entry *entry, struct br_ip *ip)
 static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
 			    struct net_device *dev)
 {
+	int idx = 0, s_idx = cb->args[1], err = 0;
 	struct net_bridge *br = netdev_priv(dev);
-	struct net_bridge_mdb_htable *mdb;
+	struct net_bridge_mdb_entry *mp;
 	struct nlattr *nest, *nest2;
-	int i, err = 0;
-	int idx = 0, s_idx = cb->args[1];
 
 	if (!br_opt_get(br, BROPT_MULTICAST_ENABLED))
 		return 0;
 
-	mdb = rcu_dereference(br->mdb);
-	if (!mdb)
-		return 0;
-
 	nest = nla_nest_start(skb, MDBA_MDB);
 	if (nest == NULL)
 		return -EMSGSIZE;
 
-	for (i = 0; i < mdb->max; i++) {
-		struct net_bridge_mdb_entry *mp;
+	hlist_for_each_entry_rcu(mp, &br->mdb_list, mdb_node) {
 		struct net_bridge_port_group *p;
 		struct net_bridge_port_group __rcu **pp;
 		struct net_bridge_port *port;
 
-		hlist_for_each_entry_rcu(mp, &mdb->mhash[i], hlist[mdb->ver]) {
 		if (idx < s_idx)
 			goto skip;
 
 		nest2 = nla_nest_start(skb, MDBA_MDB_ENTRY);
-			if (nest2 == NULL) {
+		if (!nest2) {
 			err = -EMSGSIZE;
-				goto out;
+			break;
 		}
 
-			for (pp = &mp->ports;
-			     (p = rcu_dereference(*pp)) != NULL;
+		for (pp = &mp->ports; (p = rcu_dereference(*pp)) != NULL;
 		      pp = &p->next) {
 			struct nlattr *nest_ent;
 			struct br_mdb_entry e;
@@ -132,8 +124,7 @@ static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
 				e.addr.u.ip6 = p->addr.u.ip6;
 #endif
 			e.addr.proto = p->addr.proto;
-				nest_ent = nla_nest_start(skb,
-							  MDBA_MDB_ENTRY_INFO);
+			nest_ent = nla_nest_start(skb, MDBA_MDB_ENTRY_INFO);
 			if (!nest_ent) {
 				nla_nest_cancel(skb, nest2);
 				err = -EMSGSIZE;
@@ -151,10 +142,9 @@ static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
 			nla_nest_end(skb, nest_ent);
 		}
 		nla_nest_end(skb, nest2);
-		skip:
+skip:
 		idx++;
 	}
-	}
 
 out:
 	cb->args[1] = idx;
@@ -203,8 +193,7 @@ static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
 	rcu_read_lock();
 
-	/* In theory this could be wrapped to 0... */
-	cb->seq = net->dev_base_seq + br_mdb_rehash_seq;
+	cb->seq = net->dev_base_seq;
 
 	for_each_netdev_rcu(net, dev) {
 		if (dev->priv_flags & IFF_EBRIDGE) {
@@ -297,7 +286,6 @@ static void br_mdb_complete(struct net_device *dev, int err, void *priv)
 	struct br_mdb_complete_info *data = priv;
 	struct net_bridge_port_group __rcu **pp;
 	struct net_bridge_port_group *p;
-	struct net_bridge_mdb_htable *mdb;
 	struct net_bridge_mdb_entry *mp;
 	struct net_bridge_port *port = data->port;
 	struct net_bridge *br = port->br;
@@ -306,8 +294,7 @@ static void br_mdb_complete(struct net_device *dev, int err, void *priv)
 		goto err;
 
 	spin_lock_bh(&br->multicast_lock);
-	mdb = mlock_dereference(br->mdb, br);
-	mp = br_mdb_ip_get(mdb, &data->ip);
+	mp = br_mdb_ip_get(br, &data->ip);
 	if (!mp)
 		goto out;
 	for (pp = &mp->ports; (p = mlock_dereference(*pp, br)) != NULL;
@@ -588,14 +575,12 @@ static int br_mdb_add_group(struct net_bridge *br, struct net_bridge_port *port,
 	struct net_bridge_mdb_entry *mp;
 	struct net_bridge_port_group *p;
 	struct net_bridge_port_group __rcu **pp;
-	struct net_bridge_mdb_htable *mdb;
 	unsigned long now = jiffies;
 	int err;
 
-	mdb = mlock_dereference(br->mdb, br);
-	mp = br_mdb_ip_get(mdb, group);
+	mp = br_mdb_ip_get(br, group);
 	if (!mp) {
-		mp = br_multicast_new_group(br, port, group);
+		mp = br_multicast_new_group(br, group);
 		err = PTR_ERR_OR_ZERO(mp);
 		if (err)
 			return err;
@@ -696,7 +681,6 @@ static int br_mdb_add(struct sk_buff *skb, struct nlmsghdr *nlh,
 
 static int __br_mdb_del(struct net_bridge *br, struct br_mdb_entry *entry)
 {
-	struct net_bridge_mdb_htable *mdb;
 	struct net_bridge_mdb_entry *mp;
 	struct net_bridge_port_group *p;
 	struct net_bridge_port_group __rcu **pp;
@@ -709,9 +693,7 @@ static int __br_mdb_del(struct net_bridge *br, struct br_mdb_entry *entry)
 	__mdb_entry_to_br_ip(entry, &ip);
 
 	spin_lock_bh(&br->multicast_lock);
-	mdb = mlock_dereference(br->mdb, br);
-
-	mp = br_mdb_ip_get(mdb, &ip);
+	mp = br_mdb_ip_get(br, &ip);
 	if (!mp)
 		goto unlock;
 
@@ -728,7 +710,7 @@ static int __br_mdb_del(struct net_bridge *br, struct br_mdb_entry *entry)
 		rcu_assign_pointer(*pp, p->next);
 		hlist_del_init(&p->mglist);
 		del_timer(&p->timer);
-		call_rcu_bh(&p->rcu, br_multicast_free_pg);
+		kfree_rcu(p, rcu);
 		err = 0;
 
 		if (!mp->ports && !mp->host_joined &&

net/bridge/br_multicast.c

@@ -37,6 +37,14 @@
 
 #include "br_private.h"
 
+static const struct rhashtable_params br_mdb_rht_params = {
+	.head_offset = offsetof(struct net_bridge_mdb_entry, rhnode),
+	.key_offset = offsetof(struct net_bridge_mdb_entry, addr),
+	.key_len = sizeof(struct br_ip),
+	.automatic_shrinking = true,
+	.locks_mul = 1,
+};
+
 static void br_multicast_start_querier(struct net_bridge *br,
 				       struct bridge_mcast_own_query *query);
 static void br_multicast_add_router(struct net_bridge *br,
@@ -54,7 +62,6 @@ static void br_ip6_multicast_leave_group(struct net_bridge *br,
 					 const struct in6_addr *group,
 					 __u16 vid, const unsigned char *src);
 #endif
-unsigned int br_mdb_rehash_seq;
 
 static inline int br_ip_equal(const struct br_ip *a, const struct br_ip *b)
 {
@@ -73,89 +80,58 @@ static inline int br_ip_equal(const struct br_ip *a, const struct br_ip *b)
 	return 0;
 }
 
-static inline int __br_ip4_hash(struct net_bridge_mdb_htable *mdb, __be32 ip,
-				__u16 vid)
-{
-	return jhash_2words((__force u32)ip, vid, mdb->secret) & (mdb->max - 1);
-}
-
-#if IS_ENABLED(CONFIG_IPV6)
-static inline int __br_ip6_hash(struct net_bridge_mdb_htable *mdb,
-				const struct in6_addr *ip,
-				__u16 vid)
-{
-	return jhash_2words(ipv6_addr_hash(ip), vid,
-			    mdb->secret) & (mdb->max - 1);
-}
-#endif
-
-static inline int br_ip_hash(struct net_bridge_mdb_htable *mdb,
-			     struct br_ip *ip)
+static struct net_bridge_mdb_entry *br_mdb_ip_get_rcu(struct net_bridge *br,
+						      struct br_ip *dst)
 {
-	switch (ip->proto) {
-	case htons(ETH_P_IP):
-		return __br_ip4_hash(mdb, ip->u.ip4, ip->vid);
-#if IS_ENABLED(CONFIG_IPV6)
-	case htons(ETH_P_IPV6):
-		return __br_ip6_hash(mdb, &ip->u.ip6, ip->vid);
-#endif
-	}
-	return 0;
+	return rhashtable_lookup(&br->mdb_hash_tbl, dst, br_mdb_rht_params);
 }
 
-static struct net_bridge_mdb_entry *__br_mdb_ip_get(
-	struct net_bridge_mdb_htable *mdb, struct br_ip *dst, int hash)
+struct net_bridge_mdb_entry *br_mdb_ip_get(struct net_bridge *br,
+					   struct br_ip *dst)
 {
-	struct net_bridge_mdb_entry *mp;
+	struct net_bridge_mdb_entry *ent;
 
-	hlist_for_each_entry_rcu(mp, &mdb->mhash[hash], hlist[mdb->ver]) {
-		if (br_ip_equal(&mp->addr, dst))
-			return mp;
-	}
+	lockdep_assert_held_once(&br->multicast_lock);
 
-	return NULL;
-}
-
-struct net_bridge_mdb_entry *br_mdb_ip_get(struct net_bridge_mdb_htable *mdb,
-					   struct br_ip *dst)
-{
-	if (!mdb)
-		return NULL;
+	rcu_read_lock();
+	ent = rhashtable_lookup(&br->mdb_hash_tbl, dst, br_mdb_rht_params);
+	rcu_read_unlock();
 
-	return __br_mdb_ip_get(mdb, dst, br_ip_hash(mdb, dst));
+	return ent;
 }
 
-static struct net_bridge_mdb_entry *br_mdb_ip4_get(
-	struct net_bridge_mdb_htable *mdb, __be32 dst, __u16 vid)
+static struct net_bridge_mdb_entry *br_mdb_ip4_get(struct net_bridge *br,
+						   __be32 dst, __u16 vid)
 {
 	struct br_ip br_dst;
 
+	memset(&br_dst, 0, sizeof(br_dst));
 	br_dst.u.ip4 = dst;
 	br_dst.proto = htons(ETH_P_IP);
 	br_dst.vid = vid;
 
-	return br_mdb_ip_get(mdb, &br_dst);
+	return br_mdb_ip_get(br, &br_dst);
 }
 
 #if IS_ENABLED(CONFIG_IPV6)
-static struct net_bridge_mdb_entry *br_mdb_ip6_get(
-	struct net_bridge_mdb_htable *mdb, const struct in6_addr *dst,
+static struct net_bridge_mdb_entry *br_mdb_ip6_get(struct net_bridge *br,
+						   const struct in6_addr *dst,
 						   __u16 vid)
 {
 	struct br_ip br_dst;
 
+	memset(&br_dst, 0, sizeof(br_dst));
 	br_dst.u.ip6 = *dst;
 	br_dst.proto = htons(ETH_P_IPV6);
 	br_dst.vid = vid;
 
-	return br_mdb_ip_get(mdb, &br_dst);
+	return br_mdb_ip_get(br, &br_dst);
 }
 #endif
 
 struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge *br,
 					struct sk_buff *skb, u16 vid)
 {
-	struct net_bridge_mdb_htable *mdb = rcu_dereference(br->mdb);
 	struct br_ip ip;
 
 	if (!br_opt_get(br, BROPT_MULTICAST_ENABLED))
@@ -164,6 +140,7 @@ struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge *br,
 	if (BR_INPUT_SKB_CB(skb)->igmp)
 		return NULL;
 
+	memset(&ip, 0, sizeof(ip));
 	ip.proto = skb->protocol;
 	ip.vid = vid;
 
@@ -180,70 +157,13 @@ struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge *br,
 		return NULL;
 	}
 
-	return br_mdb_ip_get(mdb, &ip);
-}
-
-static void br_mdb_free(struct rcu_head *head)
-{
-	struct net_bridge_mdb_htable *mdb =
-		container_of(head, struct net_bridge_mdb_htable, rcu);
-	struct net_bridge_mdb_htable *old = mdb->old;
-
-	mdb->old = NULL;
-	kfree(old->mhash);
-	kfree(old);
-}
-
-static int br_mdb_copy(struct net_bridge_mdb_htable *new,
-		       struct net_bridge_mdb_htable *old,
-		       int elasticity)
-{
-	struct net_bridge_mdb_entry *mp;
-	int maxlen;
-	int len;
-	int i;
-
-	for (i = 0; i < old->max; i++)
-		hlist_for_each_entry(mp, &old->mhash[i], hlist[old->ver])
-			hlist_add_head(&mp->hlist[new->ver],
-				       &new->mhash[br_ip_hash(new, &mp->addr)]);
-
-	if (!elasticity)
-		return 0;
-
-	maxlen = 0;
-	for (i = 0; i < new->max; i++) {
-		len = 0;
-		hlist_for_each_entry(mp, &new->mhash[i], hlist[new->ver])
-			len++;
-		if (len > maxlen)
-			maxlen = len;
-	}
-
-	return maxlen > elasticity ? -EINVAL : 0;
-}
-
-void br_multicast_free_pg(struct rcu_head *head)
-{
-	struct net_bridge_port_group *p =
-		container_of(head, struct net_bridge_port_group, rcu);
-
-	kfree(p);
-}
-
-static void br_multicast_free_group(struct rcu_head *head)
-{
-	struct net_bridge_mdb_entry *mp =
-		container_of(head, struct net_bridge_mdb_entry, rcu);
-
-	kfree(mp);
+	return br_mdb_ip_get_rcu(br, &ip);
 }
 
 static void br_multicast_group_expired(struct timer_list *t)
 {
 	struct net_bridge_mdb_entry *mp = from_timer(mp, t, timer);
 	struct net_bridge *br = mp->br;
-	struct net_bridge_mdb_htable *mdb;
 
 	spin_lock(&br->multicast_lock);
 	if (!netif_running(br->dev) || timer_pending(&mp->timer))
@@ -255,12 +175,11 @@ static void br_multicast_group_expired(struct timer_list *t)
 	if (mp->ports)
 		goto out;
 
-	mdb = mlock_dereference(br->mdb, br);
-
-	hlist_del_rcu(&mp->hlist[mdb->ver]);
-	mdb->size--;
+	rhashtable_remove_fast(&br->mdb_hash_tbl, &mp->rhnode,
+			       br_mdb_rht_params);
+	hlist_del_rcu(&mp->mdb_node);
 
-	call_rcu_bh(&mp->rcu, br_multicast_free_group);
+	kfree_rcu(mp, rcu);
 
 out:
 	spin_unlock(&br->multicast_lock);
@@ -269,14 +188,11 @@ static void br_multicast_group_expired(struct timer_list *t)
 static void br_multicast_del_pg(struct net_bridge *br,
 				struct net_bridge_port_group *pg)
 {
-	struct net_bridge_mdb_htable *mdb;
 	struct net_bridge_mdb_entry *mp;
 	struct net_bridge_port_group *p;
 	struct net_bridge_port_group __rcu **pp;
 
-	mdb = mlock_dereference(br->mdb, br);
-
-	mp = br_mdb_ip_get(mdb, &pg->addr);
+	mp = br_mdb_ip_get(br, &pg->addr);
 	if (WARN_ON(!mp))
 		return;
 
@@ -291,7 +207,7 @@ static void br_multicast_del_pg(struct net_bridge *br,
 		del_timer(&p->timer);
 		br_mdb_notify(br->dev, p->port, &pg->addr, RTM_DELMDB,
 			      p->flags);
-		call_rcu_bh(&p->rcu, br_multicast_free_pg);
+		kfree_rcu(p, rcu);
 
 		if (!mp->ports && !mp->host_joined &&
 		    netif_running(br->dev))
@@ -319,53 +235,6 @@ static void br_multicast_port_group_expired(struct timer_list *t)
 	spin_unlock(&br->multicast_lock);
 }
 
-static int br_mdb_rehash(struct net_bridge_mdb_htable __rcu **mdbp, int max,
-			 int elasticity)
-{
-	struct net_bridge_mdb_htable *old = rcu_dereference_protected(*mdbp, 1);
-	struct net_bridge_mdb_htable *mdb;
-	int err;
-
-	mdb = kmalloc(sizeof(*mdb), GFP_ATOMIC);
-	if (!mdb)
-		return -ENOMEM;
-
-	mdb->max = max;
-	mdb->old = old;
-
-	mdb->mhash = kcalloc(max, sizeof(*mdb->mhash), GFP_ATOMIC);
-	if (!mdb->mhash) {
-		kfree(mdb);
-		return -ENOMEM;
-	}
-
-	mdb->size = old ? old->size : 0;
-	mdb->ver = old ? old->ver ^ 1 : 0;
-
-	if (!old || elasticity)
-		get_random_bytes(&mdb->secret, sizeof(mdb->secret));
-	else
-		mdb->secret = old->secret;
-
-	if (!old)
-		goto out;
-
-	err = br_mdb_copy(mdb, old, elasticity);
-	if (err) {
-		kfree(mdb->mhash);
-		kfree(mdb);
-		return err;
-	}
-
-	br_mdb_rehash_seq++;
-	call_rcu_bh(&mdb->rcu, br_mdb_free);
-
-out:
-	rcu_assign_pointer(*mdbp, mdb);
-
-	return 0;
-}
-
 static struct sk_buff *br_ip4_multicast_alloc_query(struct net_bridge *br,
 						    __be32 group,
 						    u8 *igmp_type)
@@ -589,111 +458,19 @@ static struct sk_buff *br_multicast_alloc_query(struct net_bridge *br,
 	return NULL;
 }
 
-static struct net_bridge_mdb_entry *br_multicast_get_group(
-	struct net_bridge *br, struct net_bridge_port *port,
-	struct br_ip *group, int hash)
-{
-	struct net_bridge_mdb_htable *mdb;
-	struct net_bridge_mdb_entry *mp;
-	unsigned int count = 0;
-	unsigned int max;
-	int elasticity;
-	int err;
-
-	mdb = rcu_dereference_protected(br->mdb, 1);
-	hlist_for_each_entry(mp, &mdb->mhash[hash], hlist[mdb->ver]) {
-		count++;
-		if (unlikely(br_ip_equal(group, &mp->addr)))
-			return mp;
-	}
-
-	elasticity = 0;
-	max = mdb->max;
-
-	if (unlikely(count > br->hash_elasticity && count)) {
-		if (net_ratelimit())
-			br_info(br, "Multicast hash table "
-				"chain limit reached: %s\n",
-				port ? port->dev->name : br->dev->name);
-
-		elasticity = br->hash_elasticity;
-	}
-
-	if (mdb->size >= max) {
-		max *= 2;
-		if (unlikely(max > br->hash_max)) {
-			br_warn(br, "Multicast hash table maximum of %d "
-				"reached, disabling snooping: %s\n",
-				br->hash_max,
-				port ? port->dev->name : br->dev->name);
-			err = -E2BIG;
-disable:
-			br_opt_toggle(br, BROPT_MULTICAST_ENABLED, false);
-			goto err;
-		}
-	}
-
-	if (max > mdb->max || elasticity) {
-		if (mdb->old) {
-			if (net_ratelimit())
-				br_info(br, "Multicast hash table "
-					"on fire: %s\n",
-					port ? port->dev->name : br->dev->name);
-			err = -EEXIST;
-			goto err;
-		}
-
-		err = br_mdb_rehash(&br->mdb, max, elasticity);
-		if (err) {
-			br_warn(br, "Cannot rehash multicast "
-				"hash table, disabling snooping: %s, %d, %d\n",
-				port ? port->dev->name : br->dev->name,
-				mdb->size, err);
-			goto disable;
-		}
-
-		err = -EAGAIN;
-		goto err;
-	}
-
-	return NULL;
-
-err:
-	mp = ERR_PTR(err);
-	return mp;
-}
-
 struct net_bridge_mdb_entry *br_multicast_new_group(struct net_bridge *br,
-						    struct net_bridge_port *p,
 						    struct br_ip *group)
 {
-	struct net_bridge_mdb_htable *mdb;
 	struct net_bridge_mdb_entry *mp;
-	int hash;
 	int err;
 
-	mdb = rcu_dereference_protected(br->mdb, 1);
-	if (!mdb) {
-		err = br_mdb_rehash(&br->mdb, BR_HASH_SIZE, 0);
-		if (err)
-			return ERR_PTR(err);
-		goto rehash;
-	}
-
-	hash = br_ip_hash(mdb, group);
-	mp = br_multicast_get_group(br, p, group, hash);
-	switch (PTR_ERR(mp)) {
-	case 0:
-		break;
-
-	case -EAGAIN:
-rehash:
-		mdb = rcu_dereference_protected(br->mdb, 1);
-		hash = br_ip_hash(mdb, group);
-		break;
+	mp = br_mdb_ip_get(br, group);
+	if (mp)
+		return mp;
 
-	default:
-		goto out;
+	if (atomic_read(&br->mdb_hash_tbl.nelems) >= br->hash_max) {
+		br_opt_toggle(br, BROPT_MULTICAST_ENABLED, false);
+		return ERR_PTR(-E2BIG);
 	}
 
 	mp = kzalloc(sizeof(*mp), GFP_ATOMIC);
@@ -703,11 +480,15 @@ struct net_bridge_mdb_entry *br_multicast_new_group(struct net_bridge *br,
 	mp->br = br;
 	mp->addr = *group;
 	timer_setup(&mp->timer, br_multicast_group_expired, 0);
+	err = rhashtable_lookup_insert_fast(&br->mdb_hash_tbl, &mp->rhnode,
+					    br_mdb_rht_params);
+	if (err) {
+		kfree(mp);
+		mp = ERR_PTR(err);
+	} else {
+		hlist_add_head_rcu(&mp->mdb_node, &br->mdb_list);
+	}
 
-	hlist_add_head_rcu(&mp->hlist[mdb->ver], &mdb->mhash[hash]);
-	mdb->size++;
-
-out:
 	return mp;
 }
 
@@ -768,7 +549,7 @@ static int br_multicast_add_group(struct net_bridge *br,
 	    (port && port->state == BR_STATE_DISABLED))
 		goto out;
 
-	mp = br_multicast_new_group(br, port, group);
+	mp = br_multicast_new_group(br, group);
 	err = PTR_ERR(mp);
 	if (IS_ERR(mp))
 		goto err;
@@ -837,6 +618,7 @@ static int br_ip6_multicast_add_group(struct net_bridge *br,
 	if (ipv6_addr_is_ll_all_nodes(group))
 		return 0;
 
+	memset(&br_group, 0, sizeof(br_group));
 	br_group.u.ip6 = *group;
 	br_group.proto = htons(ETH_P_IPV6);
 	br_group.vid = vid;
@@ -1483,7 +1265,7 @@ static void br_ip4_multicast_query(struct net_bridge *br,
 		goto out;
 	}
 
-	mp = br_mdb_ip4_get(mlock_dereference(br->mdb, br), group, vid);
+	mp = br_mdb_ip4_get(br, group, vid);
 	if (!mp)
 		goto out;
 
@@ -1567,7 +1349,7 @@ static int br_ip6_multicast_query(struct net_bridge *br,
 		goto out;
 	}
 
-	mp = br_mdb_ip6_get(mlock_dereference(br->mdb, br), group, vid);
+	mp = br_mdb_ip6_get(br, group, vid);
 	if (!mp)
 		goto out;
 
@@ -1601,7 +1383,6 @@ br_multicast_leave_group(struct net_bridge *br,
 			 struct bridge_mcast_own_query *own_query,
 			 const unsigned char *src)
 {
-	struct net_bridge_mdb_htable *mdb;
 	struct net_bridge_mdb_entry *mp;
 	struct net_bridge_port_group *p;
 	unsigned long now;
@@ -1612,8 +1393,7 @@ br_multicast_leave_group(struct net_bridge *br,
 	    (port && port->state == BR_STATE_DISABLED))
 		goto out;
 
-	mdb = mlock_dereference(br->mdb, br);
-	mp = br_mdb_ip_get(mdb, group);
+	mp = br_mdb_ip_get(br, group);
 	if (!mp)
 		goto out;
 
@@ -1629,7 +1409,7 @@ br_multicast_leave_group(struct net_bridge *br,
 			rcu_assign_pointer(*pp, p->next);
 			hlist_del_init(&p->mglist);
 			del_timer(&p->timer);
-			call_rcu_bh(&p->rcu, br_multicast_free_pg);
+			kfree_rcu(p, rcu);
 			br_mdb_notify(br->dev, port, group, RTM_DELMDB,
 				      p->flags);
 
@@ -1961,8 +1741,7 @@ static void br_ip6_multicast_query_expired(struct timer_list *t)
 
 void br_multicast_init(struct net_bridge *br)
 {
-	br->hash_elasticity = 4;
-	br->hash_max = 512;
+	br->hash_max = BR_MULTICAST_DEFAULT_HASH_MAX;
 
 	br->multicast_router = MDB_RTR_TYPE_TEMP_QUERY;
 	br->multicast_last_member_count = 2;
@@ -1999,6 +1778,7 @@ void br_multicast_init(struct net_bridge *br)
 	timer_setup(&br->ip6_own_query.timer,
 		    br_ip6_multicast_query_expired, 0);
 #endif
+	INIT_HLIST_HEAD(&br->mdb_list);
 }
 
 static void __br_multicast_open(struct net_bridge *br,
@@ -2033,40 +1813,20 @@ void br_multicast_stop(struct net_bridge *br)
 
 void br_multicast_dev_del(struct net_bridge *br)
 {
-	struct net_bridge_mdb_htable *mdb;
 	struct net_bridge_mdb_entry *mp;
-	struct hlist_node *n;
-	u32 ver;
-	int i;
+	struct hlist_node *tmp;
 
 	spin_lock_bh(&br->multicast_lock);
-	mdb = mlock_dereference(br->mdb, br);
-	if (!mdb)
-		goto out;
-
-	br->mdb = NULL;
-
-	ver = mdb->ver;
-	for (i = 0; i < mdb->max; i++) {
-		hlist_for_each_entry_safe(mp, n, &mdb->mhash[i],
-					  hlist[ver]) {
+	hlist_for_each_entry_safe(mp, tmp, &br->mdb_list, mdb_node) {
 		del_timer(&mp->timer);
-			call_rcu_bh(&mp->rcu, br_multicast_free_group);
-		}
+		rhashtable_remove_fast(&br->mdb_hash_tbl, &mp->rhnode,
+				       br_mdb_rht_params);
+		hlist_del_rcu(&mp->mdb_node);
+		kfree_rcu(mp, rcu);
 	}
-
-	if (mdb->old) {
 	spin_unlock_bh(&br->multicast_lock);
-		rcu_barrier_bh();
-		spin_lock_bh(&br->multicast_lock);
-		WARN_ON(mdb->old);
-	}
 
-	mdb->old = mdb;
-	call_rcu_bh(&mdb->rcu, br_mdb_free);
-
-out:
-	spin_unlock_bh(&br->multicast_lock);
+	rcu_barrier();
 }
 
 int br_multicast_set_router(struct net_bridge *br, unsigned long val)
@@ -2176,7 +1936,6 @@ static void br_multicast_start_querier(struct net_bridge *br,
 
 int br_multicast_toggle(struct net_bridge *br, unsigned long val)
 {
-	struct net_bridge_mdb_htable *mdb;
 	struct net_bridge_port *port;
 	int err = 0;
 
@@ -2192,21 +1951,6 @@ int br_multicast_toggle(struct net_bridge *br, unsigned long val)
 	if (!netif_running(br->dev))
 		goto unlock;
 
-	mdb = mlock_dereference(br->mdb, br);
-	if (mdb) {
-		if (mdb->old) {
-			err = -EEXIST;
-rollback:
-			br_opt_toggle(br, BROPT_MULTICAST_ENABLED, false);
-			goto unlock;
-		}
-
-		err = br_mdb_rehash(&br->mdb, mdb->max,
-				    br->hash_elasticity);
-		if (err)
-			goto rollback;
-	}
-
 	br_multicast_open(br);
 	list_for_each_entry(port, &br->port_list, list)
 		__br_multicast_enable_port(port);
@@ -2271,45 +2015,6 @@ int br_multicast_set_querier(struct net_bridge *br, unsigned long val)
 	return 0;
 }
 
-int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val)
-{
-	int err = -EINVAL;
-	u32 old;
-	struct net_bridge_mdb_htable *mdb;
-
-	spin_lock_bh(&br->multicast_lock);
-	if (!is_power_of_2(val))
-		goto unlock;
-
-	mdb = mlock_dereference(br->mdb, br);
-	if (mdb && val < mdb->size)
-		goto unlock;
-
-	err = 0;
-
-	old = br->hash_max;
-	br->hash_max = val;
-
-	if (mdb) {
-		if (mdb->old) {
-			err = -EEXIST;
-rollback:
-			br->hash_max = old;
-			goto unlock;
-		}
-
-		err = br_mdb_rehash(&br->mdb, br->hash_max,
-				    br->hash_elasticity);
-		if (err)
-			goto rollback;
-	}
-
-unlock:
-	spin_unlock_bh(&br->multicast_lock);
-
-	return err;
-}
-
 int br_multicast_set_igmp_version(struct net_bridge *br, unsigned long val)
 {
 	/* Currently we support only version 2 and 3 */
@@ -2646,3 +2351,13 @@ void br_multicast_get_stats(const struct net_bridge *br,
 	}
 	memcpy(dest, &tdst, sizeof(*dest));
 }
+
+int br_mdb_hash_init(struct net_bridge *br)
+{
+	return rhashtable_init(&br->mdb_hash_tbl, &br_mdb_rht_params);
+}
+
+void br_mdb_hash_fini(struct net_bridge *br)
+{
+	rhashtable_destroy(&br->mdb_hash_tbl);
+}

net/bridge/br_netlink.c

@@ -1189,19 +1189,12 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 			return err;
 	}
 
-	if (data[IFLA_BR_MCAST_HASH_ELASTICITY]) {
-		u32 val = nla_get_u32(data[IFLA_BR_MCAST_HASH_ELASTICITY]);
+	if (data[IFLA_BR_MCAST_HASH_ELASTICITY])
+		br_warn(br, "the hash_elasticity option has been deprecated and is always %u\n",
+			RHT_ELASTICITY);
 
-		br->hash_elasticity = val;
-	}
-
-	if (data[IFLA_BR_MCAST_HASH_MAX]) {
-		u32 hash_max = nla_get_u32(data[IFLA_BR_MCAST_HASH_MAX]);
-
-		err = br_multicast_set_hash_max(br, hash_max);
-		if (err)
-			return err;
-	}
+	if (data[IFLA_BR_MCAST_HASH_MAX])
+		br->hash_max = nla_get_u32(data[IFLA_BR_MCAST_HASH_MAX]);
 
 	if (data[IFLA_BR_MCAST_LAST_MEMBER_CNT]) {
 		u32 val = nla_get_u32(data[IFLA_BR_MCAST_LAST_MEMBER_CNT]);
@@ -1457,8 +1450,7 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
 		       br_opt_get(br, BROPT_MULTICAST_QUERIER)) ||
 	    nla_put_u8(skb, IFLA_BR_MCAST_STATS_ENABLED,
 		       br_opt_get(br, BROPT_MULTICAST_STATS_ENABLED)) ||
-	    nla_put_u32(skb, IFLA_BR_MCAST_HASH_ELASTICITY,
-			br->hash_elasticity) ||
+	    nla_put_u32(skb, IFLA_BR_MCAST_HASH_ELASTICITY, RHT_ELASTICITY) ||
 	    nla_put_u32(skb, IFLA_BR_MCAST_HASH_MAX, br->hash_max) ||
 	    nla_put_u32(skb, IFLA_BR_MCAST_LAST_MEMBER_CNT,
 			br->multicast_last_member_count) ||

net/bridge/br_private.h

@@ -31,6 +31,8 @@
 #define BR_PORT_BITS	10
 #define BR_MAX_PORTS	(1<<BR_PORT_BITS)
 
+#define BR_MULTICAST_DEFAULT_HASH_MAX 4096
+
 #define BR_VERSION	"2.3"
 
 /* Control of forwarding link local multicast */
@@ -213,23 +215,14 @@ struct net_bridge_port_group {
 };
 
 struct net_bridge_mdb_entry {
-	struct hlist_node		hlist[2];
+	struct rhash_head		rhnode;
 	struct net_bridge		*br;
 	struct net_bridge_port_group __rcu *ports;
 	struct rcu_head			rcu;
 	struct timer_list		timer;
 	struct br_ip			addr;
 	bool				host_joined;
-};
-
-struct net_bridge_mdb_htable {
-	struct hlist_head		*mhash;
-	struct rcu_head			rcu;
-	struct net_bridge_mdb_htable	*old;
-	u32				size;
-	u32				max;
-	u32				secret;
-	u32				ver;
+	struct hlist_node		mdb_node;
 };
 
 struct net_bridge_port {
@@ -381,7 +374,6 @@ struct net_bridge {
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 
-	u32				hash_elasticity;
 	u32				hash_max;
 
 	u32				multicast_last_member_count;
@@ -400,7 +392,9 @@ struct net_bridge {
 	unsigned long			multicast_query_response_interval;
 	unsigned long			multicast_startup_query_interval;
 
-	struct net_bridge_mdb_htable __rcu *mdb;
+	struct rhashtable		mdb_hash_tbl;
+
+	struct hlist_head		mdb_list;
 	struct hlist_head		router_list;
 
 	struct timer_list		multicast_router_timer;
@@ -659,7 +653,6 @@ int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd,
 
 /* br_multicast.c */
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
-extern unsigned int br_mdb_rehash_seq;
 int br_multicast_rcv(struct net_bridge *br, struct net_bridge_port *port,
 		     struct sk_buff *skb, u16 vid);
 struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge *br,
@@ -684,17 +677,15 @@ int br_multicast_set_igmp_version(struct net_bridge *br, unsigned long val);
 int br_multicast_set_mld_version(struct net_bridge *br, unsigned long val);
 #endif
 struct net_bridge_mdb_entry *
-br_mdb_ip_get(struct net_bridge_mdb_htable *mdb, struct br_ip *dst);
+br_mdb_ip_get(struct net_bridge *br, struct br_ip *dst);
 struct net_bridge_mdb_entry *
-br_multicast_new_group(struct net_bridge *br, struct net_bridge_port *port,
-		       struct br_ip *group);
-void br_multicast_free_pg(struct rcu_head *head);
+br_multicast_new_group(struct net_bridge *br, struct br_ip *group);
 struct net_bridge_port_group *
 br_multicast_new_port_group(struct net_bridge_port *port, struct br_ip *group,
 			    struct net_bridge_port_group __rcu *next,
 			    unsigned char flags, const unsigned char *src);
-void br_mdb_init(void);
-void br_mdb_uninit(void);
+int br_mdb_hash_init(struct net_bridge *br);
+void br_mdb_hash_fini(struct net_bridge *br);
 void br_mdb_notify(struct net_device *dev, struct net_bridge_port *port,
 		   struct br_ip *group, int type, u8 flags);
 void br_rtr_notify(struct net_device *dev, struct net_bridge_port *port,
@@ -706,6 +697,8 @@ void br_multicast_uninit_stats(struct net_bridge *br);
 void br_multicast_get_stats(const struct net_bridge *br,
 			    const struct net_bridge_port *p,
 			    struct br_mcast_stats *dest);
+void br_mdb_init(void);
+void br_mdb_uninit(void);
 
 #define mlock_dereference(X, br) \
 	rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock))
@@ -831,6 +824,15 @@ static inline void br_mdb_uninit(void)
 {
 }
 
+static inline int br_mdb_hash_init(struct net_bridge *br)
+{
+	return 0;
+}
+
+static inline void br_mdb_hash_fini(struct net_bridge *br)
+{
+}
+
 static inline void br_multicast_count(struct net_bridge *br,
 				      const struct net_bridge_port *p,
 				      const struct sk_buff *skb,

net/bridge/br_sysfs_br.c

@@ -424,13 +424,13 @@ static DEVICE_ATTR_RW(multicast_querier);
 static ssize_t hash_elasticity_show(struct device *d,
 				    struct device_attribute *attr, char *buf)
 {
-	struct net_bridge *br = to_bridge(d);
-	return sprintf(buf, "%u\n", br->hash_elasticity);
+	return sprintf(buf, "%u\n", RHT_ELASTICITY);
 }
 
 static int set_elasticity(struct net_bridge *br, unsigned long val)
 {
-	br->hash_elasticity = val;
+	br_warn(br, "the hash_elasticity option has been deprecated and is always %u\n",
+		RHT_ELASTICITY);
 	return 0;
 }
 
@@ -449,10 +449,16 @@ static ssize_t hash_max_show(struct device *d, struct device_attribute *attr,
 	return sprintf(buf, "%u\n", br->hash_max);
 }
 
+static int set_hash_max(struct net_bridge *br, unsigned long val)
+{
+	br->hash_max = val;
+	return 0;
+}
+
 static ssize_t hash_max_store(struct device *d, struct device_attribute *attr,
 			      const char *buf, size_t len)
 {
-	return store_bridge_parm(d, buf, len, br_multicast_set_hash_max);
+	return store_bridge_parm(d, buf, len, set_hash_max);
 }
 static DEVICE_ATTR_RW(hash_max);