bridge: add RCU annotation to bridge multicast table

Add modern __rcu annotatations to bridge multicast table.
Use newer hlist macros to avoid direct access to hlist internals.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 56 insertions, 32 deletions

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index cbfe87f0f34a..2bd11ec6d166 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -223,7 +223,7 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
         struct net_bridge_port_group *p;
         struct hlist_node *rp;
 
-        rp = rcu_dereference(br->router_list.first);
+        rp = rcu_dereference(hlist_first_rcu(&br->router_list));
         p = mdst ? rcu_dereference(mdst->ports) : NULL;
         while (p || rp) {
                 struct net_bridge_port *port, *lport, *rport;
@@ -242,7 +242,7 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
                 if ((unsigned long)lport >= (unsigned long)port)
                         p = rcu_dereference(p->next);
                 if ((unsigned long)rport >= (unsigned long)port)
-                        rp = rcu_dereference(rp->next);
+                        rp = rcu_dereference(hlist_next_rcu(rp));
         }
 
         if (!prev)
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index eb5b256ffc88..326e599f83fb 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -33,6 +33,9 @@
 
 #include "br_private.h"
 
+#define mlock_dereference(X, br) \
+        rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock))
+
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 static inline int ipv6_is_local_multicast(const struct in6_addr *addr)
 {
@@ -135,7 +138,7 @@ static struct net_bridge_mdb_entry *br_mdb_ip6_get(
 struct net_bridge_mdb_entry *br_mdb_get(struct net_bridge *br,
                                         struct sk_buff *skb)
 {
-        struct net_bridge_mdb_htable *mdb = br->mdb;
+        struct net_bridge_mdb_htable *mdb = rcu_dereference(br->mdb);
         struct br_ip ip;
 
         if (br->multicast_disabled)
@@ -235,7 +238,8 @@ static void br_multicast_group_expired(unsigned long data)
         if (mp->ports)
                 goto out;
 
-        mdb = br->mdb;
+        mdb = mlock_dereference(br->mdb, br);
+
         hlist_del_rcu(&mp->hlist[mdb->ver]);
         mdb->size--;
 
@@ -249,16 +253,20 @@ out:
 static void br_multicast_del_pg(struct net_bridge *br,
                                 struct net_bridge_port_group *pg)
 {
-        struct net_bridge_mdb_htable *mdb = br->mdb;
+        struct net_bridge_mdb_htable *mdb;
         struct net_bridge_mdb_entry *mp;
         struct net_bridge_port_group *p;
-        struct net_bridge_port_group **pp;
+        struct net_bridge_port_group __rcu **pp;
+
+        mdb = mlock_dereference(br->mdb, br);
 
         mp = br_mdb_ip_get(mdb, &pg->addr);
         if (WARN_ON(!mp))
                 return;
 
-        for (pp = &mp->ports; (p = *pp); pp = &p->next) {
+        for (pp = &mp->ports;
+             (p = mlock_dereference(*pp, br)) != NULL;
+             pp = &p->next) {
                 if (p != pg)
                         continue;
 
@@ -294,10 +302,10 @@ out:
         spin_unlock(&br->multicast_lock);
 }
 
-static int br_mdb_rehash(struct net_bridge_mdb_htable **mdbp, int max,
+static int br_mdb_rehash(struct net_bridge_mdb_htable __rcu **mdbp, int max,
                          int elasticity)
 {
-        struct net_bridge_mdb_htable *old = *mdbp;
+        struct net_bridge_mdb_htable *old = rcu_dereference_protected(*mdbp, 1);
         struct net_bridge_mdb_htable *mdb;
         int err;
 
@@ -569,7 +577,7 @@ 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 = br->mdb;
+        struct net_bridge_mdb_htable *mdb;
         struct net_bridge_mdb_entry *mp;
         struct hlist_node *p;
         unsigned count = 0;
@@ -577,6 +585,7 @@ static struct net_bridge_mdb_entry *br_multicast_get_group(
         int elasticity;
         int err;
 
+        mdb = rcu_dereference_protected(br->mdb, 1);
         hlist_for_each_entry(mp, p, &mdb->mhash[hash], hlist[mdb->ver]) {
                 count++;
                 if (unlikely(br_ip_equal(group, &mp->addr)))
@@ -642,10 +651,11 @@ static struct net_bridge_mdb_entry *br_multicast_new_group(
         struct net_bridge *br, struct net_bridge_port *port,
         struct br_ip *group)
 {
-        struct net_bridge_mdb_htable *mdb = br->mdb;
+        struct net_bridge_mdb_htable *mdb;
         struct net_bridge_mdb_entry *mp;
         int hash;
 
+        mdb = rcu_dereference_protected(br->mdb, 1);
         if (!mdb) {
                 if (br_mdb_rehash(&br->mdb, BR_HASH_SIZE, 0))
                         return NULL;
@@ -660,7 +670,7 @@ static struct net_bridge_mdb_entry *br_multicast_new_group(
 
         case -EAGAIN:
 rehash:
-                mdb = br->mdb;
+                mdb = rcu_dereference_protected(br->mdb, 1);
                 hash = br_ip_hash(mdb, group);
                 break;
 
@@ -692,7 +702,7 @@ static int br_multicast_add_group(struct net_bridge *br,
 {
         struct net_bridge_mdb_entry *mp;
         struct net_bridge_port_group *p;
-        struct net_bridge_port_group **pp;
+        struct net_bridge_port_group __rcu **pp;
         unsigned long now = jiffies;
         int err;
 
@@ -712,7 +722,9 @@ static int br_multicast_add_group(struct net_bridge *br,
                 goto out;
         }
 
-        for (pp = &mp->ports; (p = *pp); pp = &p->next) {
+        for (pp = &mp->ports;
+             (p = mlock_dereference(*pp, br)) != NULL;
+             pp = &p->next) {
                 if (p->port == port)
                         goto found;
                 if ((unsigned long)p->port < (unsigned long)port)
@@ -1106,7 +1118,7 @@ static int br_ip4_multicast_query(struct net_bridge *br,
         struct net_bridge_mdb_entry *mp;
         struct igmpv3_query *ih3;
         struct net_bridge_port_group *p;
-        struct net_bridge_port_group **pp;
+        struct net_bridge_port_group __rcu **pp;
         unsigned long max_delay;
         unsigned long now = jiffies;
         __be32 group;
@@ -1145,7 +1157,7 @@ static int br_ip4_multicast_query(struct net_bridge *br,
         if (!group)
                 goto out;
 
-        mp = br_mdb_ip4_get(br->mdb, group);
+        mp = br_mdb_ip4_get(mlock_dereference(br->mdb, br), group);
         if (!mp)
                 goto out;
 
@@ -1157,7 +1169,9 @@ static int br_ip4_multicast_query(struct net_bridge *br,
              try_to_del_timer_sync(&mp->timer) >= 0))
                 mod_timer(&mp->timer, now + max_delay);
 
-        for (pp = &mp->ports; (p = *pp); pp = &p->next) {
+        for (pp = &mp->ports;
+             (p = mlock_dereference(*pp, br)) != NULL;
+             pp = &p->next) {
                 if (timer_pending(&p->timer) ?
                     time_after(p->timer.expires, now + max_delay) :
                     try_to_del_timer_sync(&p->timer) >= 0)
@@ -1178,7 +1192,8 @@ static int br_ip6_multicast_query(struct net_bridge *br,
         struct mld_msg *mld = (struct mld_msg *) icmp6_hdr(skb);
         struct net_bridge_mdb_entry *mp;
         struct mld2_query *mld2q;
-        struct net_bridge_port_group *p, **pp;
+        struct net_bridge_port_group *p;
+        struct net_bridge_port_group __rcu **pp;
         unsigned long max_delay;
         unsigned long now = jiffies;
         struct in6_addr *group = NULL;
@@ -1214,7 +1229,7 @@ static int br_ip6_multicast_query(struct net_bridge *br,
         if (!group)
                 goto out;
 
-        mp = br_mdb_ip6_get(br->mdb, group);
+        mp = br_mdb_ip6_get(mlock_dereference(br->mdb, br), group);
         if (!mp)
                 goto out;
 
@@ -1225,7 +1240,9 @@ static int br_ip6_multicast_query(struct net_bridge *br,
              try_to_del_timer_sync(&mp->timer) >= 0))
                 mod_timer(&mp->timer, now + max_delay);
 
-        for (pp = &mp->ports; (p = *pp); pp = &p->next) {
+        for (pp = &mp->ports;
+             (p = mlock_dereference(*pp, br)) != NULL;
+             pp = &p->next) {
                 if (timer_pending(&p->timer) ?
                     time_after(p->timer.expires, now + max_delay) :
                     try_to_del_timer_sync(&p->timer) >= 0)
@@ -1254,7 +1271,7 @@ static void br_multicast_leave_group(struct net_bridge *br,
             timer_pending(&br->multicast_querier_timer))
                 goto out;
 
-        mdb = br->mdb;
+        mdb = mlock_dereference(br->mdb, br);
         mp = br_mdb_ip_get(mdb, group);
         if (!mp)
                 goto out;
@@ -1277,7 +1294,9 @@ static void br_multicast_leave_group(struct net_bridge *br,
                 goto out;
         }
 
-        for (p = mp->ports; p; p = p->next) {
+        for (p = mlock_dereference(mp->ports, br);
+             p != NULL;
+             p = mlock_dereference(p->next, br)) {
                 if (p->port != port)
                         continue;
 
@@ -1625,7 +1644,7 @@ void br_multicast_stop(struct net_bridge *br)
         del_timer_sync(&br->multicast_query_timer);
 
         spin_lock_bh(&br->multicast_lock);
-        mdb = br->mdb;
+        mdb = mlock_dereference(br->mdb, br);
         if (!mdb)
                 goto out;
 
@@ -1729,6 +1748,7 @@ int br_multicast_toggle(struct net_bridge *br, unsigned long val)
 {
         struct net_bridge_port *port;
         int err = 0;
+        struct net_bridge_mdb_htable *mdb;
 
         spin_lock(&br->multicast_lock);
         if (br->multicast_disabled == !val)
@@ -1741,15 +1761,16 @@ int br_multicast_toggle(struct net_bridge *br, unsigned long val)
         if (!netif_running(br->dev))
                 goto unlock;
 
-        if (br->mdb) {
-                if (br->mdb->old) {
+        mdb = mlock_dereference(br->mdb, br);
+        if (mdb) {
+                if (mdb->old) {
                         err = -EEXIST;
 rollback:
                         br->multicast_disabled = !!val;
                         goto unlock;
                 }
 
-                err = br_mdb_rehash(&br->mdb, br->mdb->max,
+                err = br_mdb_rehash(&br->mdb, mdb->max,
                                     br->hash_elasticity);
                 if (err)
                         goto rollback;
@@ -1774,6 +1795,7 @@ int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val)
 {
         int err = -ENOENT;
         u32 old;
+        struct net_bridge_mdb_htable *mdb;
 
         spin_lock(&br->multicast_lock);
         if (!netif_running(br->dev))
@@ -1782,7 +1804,9 @@ int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val)
         err = -EINVAL;
         if (!is_power_of_2(val))
                 goto unlock;
-        if (br->mdb && val < br->mdb->size)
+
+        mdb = mlock_dereference(br->mdb, br);
+        if (mdb && val < mdb->size)
                 goto unlock;
 
         err = 0;
@@ -1790,8 +1814,8 @@ int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val)
         old = br->hash_max;
         br->hash_max = val;
 
-        if (br->mdb) {
-                if (br->mdb->old) {
+        if (mdb) {
+                if (mdb->old) {
                         err = -EEXIST;
 rollback:
                         br->hash_max = old;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 75c90edaf7db..b862071bf601 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -72,7 +72,7 @@ struct net_bridge_fdb_entry
 
 struct net_bridge_port_group {
         struct net_bridge_port          *port;
-        struct net_bridge_port_group    *next;
+        struct net_bridge_port_group __rcu *next;
         struct hlist_node               mglist;
         struct rcu_head                 rcu;
         struct timer_list               timer;
@@ -86,7 +86,7 @@ struct net_bridge_mdb_entry
         struct hlist_node               hlist[2];
         struct hlist_node               mglist;
         struct net_bridge               *br;
-        struct net_bridge_port_group    *ports;
+        struct net_bridge_port_group __rcu *ports;
         struct rcu_head                 rcu;
         struct timer_list               timer;
         struct timer_list               query_timer;
@@ -227,7 +227,7 @@ struct net_bridge
         unsigned long                   multicast_startup_query_interval;
 
         spinlock_t                      multicast_lock;
-        struct net_bridge_mdb_htable    *mdb;
+        struct net_bridge_mdb_htable __rcu *mdb;
         struct hlist_head               router_list;
         struct hlist_head               mglist;