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: David 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

@@ -78,82 +78,72 @@ 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;
+		if (idx < s_idx)
+			goto skip;
 
-			nest2 = nla_nest_start(skb, MDBA_MDB_ENTRY);
-			if (nest2 == NULL) {
-				err = -EMSGSIZE;
-				goto out;
-			}
+		nest2 = nla_nest_start(skb, MDBA_MDB_ENTRY);
+		if (!nest2) {
+			err = -EMSGSIZE;
+			break;
+		}
 
-			for (pp = &mp->ports;
-			     (p = rcu_dereference(*pp)) != NULL;
-			      pp = &p->next) {
-				struct nlattr *nest_ent;
-				struct br_mdb_entry e;
-
-				port = p->port;
-				if (!port)
-					continue;
-
-				memset(&e, 0, sizeof(e));
-				e.ifindex = port->dev->ifindex;
-				e.vid = p->addr.vid;
-				__mdb_entry_fill_flags(&e, p->flags);
-				if (p->addr.proto == htons(ETH_P_IP))
-					e.addr.u.ip4 = p->addr.u.ip4;
+		for (pp = &mp->ports; (p = rcu_dereference(*pp)) != NULL;
+		      pp = &p->next) {
+			struct nlattr *nest_ent;
+			struct br_mdb_entry e;
+
+			port = p->port;
+			if (!port)
+				continue;
+
+			memset(&e, 0, sizeof(e));
+			e.ifindex = port->dev->ifindex;
+			e.vid = p->addr.vid;
+			__mdb_entry_fill_flags(&e, p->flags);
+			if (p->addr.proto == htons(ETH_P_IP))
+				e.addr.u.ip4 = p->addr.u.ip4;
 #if IS_ENABLED(CONFIG_IPV6)
-				if (p->addr.proto == htons(ETH_P_IPV6))
-					e.addr.u.ip6 = p->addr.u.ip6;
+			if (p->addr.proto == htons(ETH_P_IPV6))
+				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);
-				if (!nest_ent) {
-					nla_nest_cancel(skb, nest2);
-					err = -EMSGSIZE;
-					goto out;
-				}
-				if (nla_put_nohdr(skb, sizeof(e), &e) ||
-				    nla_put_u32(skb,
-						MDBA_MDB_EATTR_TIMER,
-						br_timer_value(&p->timer))) {
-					nla_nest_cancel(skb, nest_ent);
-					nla_nest_cancel(skb, nest2);
-					err = -EMSGSIZE;
-					goto out;
-				}
-				nla_nest_end(skb, nest_ent);
+			e.addr.proto = p->addr.proto;
+			nest_ent = nla_nest_start(skb, MDBA_MDB_ENTRY_INFO);
+			if (!nest_ent) {
+				nla_nest_cancel(skb, nest2);
+				err = -EMSGSIZE;
+				goto out;
 			}
-			nla_nest_end(skb, nest2);
-		skip:
-			idx++;
+			if (nla_put_nohdr(skb, sizeof(e), &e) ||
+			    nla_put_u32(skb,
+					MDBA_MDB_EATTR_TIMER,
+					br_timer_value(&p->timer))) {
+				nla_nest_cancel(skb, nest_ent);
+				nla_nest_cancel(skb, nest2);
+				err = -EMSGSIZE;
+				goto out;
+			}
+			nla_nest_end(skb, nest_ent);
 		}
+		nla_nest_end(skb, nest2);
+skip:
+		idx++;
 	}
 
 out:
@@ -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_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);