bridge: use rx_handler_data pointer to store net_bridge_port pointer

Register net_bridge_port pointer as rx_handler data pointer. As br_port is
removed from struct net_device, another netdev priv_flag is added to indicate
the device serves as a bridge port. Also rcuized pointers are now correctly
dereferenced in br_fdb.c and in netfilter parts.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

11 files changed, 55 insertions, 38 deletions

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 26637439965b..6818e609b2c0 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -242,11 +242,11 @@ int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
         struct net_bridge_fdb_entry *fdb;
         int ret;
 
-        if (!dev->br_port)
+        if (!br_port_exists(dev))
                 return 0;
 
         rcu_read_lock();
-        fdb = __br_fdb_get(dev->br_port->br, addr);
+        fdb = __br_fdb_get(br_port_get_rcu(dev)->br, addr);
         ret = fdb && fdb->dst->dev != dev &&
                 fdb->dst->state == BR_STATE_FORWARDING;
         rcu_read_unlock();
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 0d142ed0bbe3..c03d2c3ff03e 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -147,8 +147,9 @@ static void del_nbp(struct net_bridge_port *p)
 
         list_del_rcu(&p->list);
 
+        dev->priv_flags &= ~IFF_BRIDGE_PORT;
+
         netdev_rx_handler_unregister(dev);
-        rcu_assign_pointer(dev->br_port, NULL);
 
         br_multicast_del_port(p);
 
@@ -400,7 +401,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
                 return -ELOOP;
 
         /* Device is already being bridged */
-        if (dev->br_port != NULL)
+        if (br_port_exists(dev))
                 return -EBUSY;
 
         /* No bridging devices that dislike that (e.g. wireless) */
@@ -431,11 +432,11 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
         if (br_netpoll_info(br) && ((err = br_netpoll_enable(p))))
                 goto err3;
 
-        rcu_assign_pointer(dev->br_port, p);
-
-        err = netdev_rx_handler_register(dev, br_handle_frame, NULL);
+        err = netdev_rx_handler_register(dev, br_handle_frame, p);
         if (err)
-                goto err4;
+                goto err3;
+
+        dev->priv_flags |= IFF_BRIDGE_PORT;
 
         dev_disable_lro(dev);
 
@@ -457,8 +458,6 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
         kobject_uevent(&p->kobj, KOBJ_ADD);
 
         return 0;
-err4:
-        rcu_assign_pointer(dev->br_port, NULL);
 err3:
         sysfs_remove_link(br->ifobj, p->dev->name);
 err2:
@@ -477,9 +476,13 @@ put_back:
 /* called with RTNL */
 int br_del_if(struct net_bridge *br, struct net_device *dev)
 {
-        struct net_bridge_port *p = dev->br_port;
+        struct net_bridge_port *p;
+
+        if (!br_port_exists(dev))
+                return -EINVAL;
 
-        if (!p || p->br != br)
+        p = br_port_get(dev);
+        if (p->br != br)
                 return -EINVAL;
 
         del_nbp(p);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 99647d8f95c8..f076c9d79d5e 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -41,7 +41,7 @@ static int br_pass_frame_up(struct sk_buff *skb)
 int br_handle_frame_finish(struct sk_buff *skb)
 {
         const unsigned char *dest = eth_hdr(skb)->h_dest;
-        struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
+        struct net_bridge_port *p = br_port_get_rcu(skb->dev);
         struct net_bridge *br;
         struct net_bridge_fdb_entry *dst;
         struct net_bridge_mdb_entry *mdst;
@@ -111,10 +111,9 @@ drop:
 /* note: already called with rcu_read_lock (preempt_disabled) */
 static int br_handle_local_finish(struct sk_buff *skb)
 {
-        struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);
+        struct net_bridge_port *p = br_port_get_rcu(skb->dev);
 
-        if (p)
-                br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
+        br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
         return 0;        /* process further */
 }
 
@@ -151,7 +150,7 @@ struct sk_buff *br_handle_frame(struct sk_buff *skb)
         if (!skb)
                 return NULL;
 
-        p = rcu_dereference(skb->dev->br_port);
+        p = br_port_get_rcu(skb->dev);
 
         if (unlikely(is_link_local(dest))) {
                 /* Pause frames shouldn't be passed up by driver anyway */
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 0685b2558ab5..f54404ddee53 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -127,16 +127,17 @@ void br_netfilter_rtable_init(struct net_bridge *br)
 
 static inline struct rtable *bridge_parent_rtable(const struct net_device *dev)
 {
-        struct net_bridge_port *port = rcu_dereference(dev->br_port);
-
-        return port ? &port->br->fake_rtable : NULL;
+        if (!br_port_exists(dev))
+                return NULL;
+        return &br_port_get_rcu(dev)->br->fake_rtable;
 }
 
 static inline struct net_device *bridge_parent(const struct net_device *dev)
 {
-        struct net_bridge_port *port = rcu_dereference(dev->br_port);
+        if (!br_port_exists(dev))
+                return NULL;
 
-        return port ? port->br->dev : NULL;
+        return br_port_get_rcu(dev)->br->dev;
 }
 
 static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index fe0a79018ab2..4a6a378c84e3 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -120,10 +120,11 @@ static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
         idx = 0;
         for_each_netdev(net, dev) {
                 /* not a bridge port */
-                if (dev->br_port == NULL || idx < cb->args[0])
+                if (!br_port_exists(dev) || idx < cb->args[0])
                         goto skip;
 
-                if (br_fill_ifinfo(skb, dev->br_port, NETLINK_CB(cb->skb).pid,
+                if (br_fill_ifinfo(skb, br_port_get(dev),
+                                   NETLINK_CB(cb->skb).pid,
                                    cb->nlh->nlmsg_seq, RTM_NEWLINK,
                                    NLM_F_MULTI) < 0)
                         break;
@@ -168,9 +169,9 @@ static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
         if (!dev)
                 return -ENODEV;
 
-        p = dev->br_port;
-        if (!p)
+        if (!br_port_exists(dev))
                 return -EINVAL;
+        p = br_port_get(dev);
 
         /* if kernel STP is running, don't allow changes */
         if (p->br->stp_enabled == BR_KERNEL_STP)
diff --git a/net/bridge/br_notify.c b/net/bridge/br_notify.c
index 717e1fd6133c..404d4e14c6a7 100644
--- a/net/bridge/br_notify.c
+++ b/net/bridge/br_notify.c
@@ -32,14 +32,15 @@ struct notifier_block br_device_notifier = {
 static int br_device_event(struct notifier_block *unused, unsigned long event, void *ptr)
 {
         struct net_device *dev = ptr;
-        struct net_bridge_port *p = dev->br_port;
+        struct net_bridge_port *p = br_port_get(dev);
         struct net_bridge *br;
         int err;
 
         /* not a port of a bridge */
-        if (p == NULL)
+        if (!br_port_exists(dev))
                 return NOTIFY_DONE;
 
+        p = br_port_get(dev);
         br = p->br;
 
         switch (event) {
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 0f5394c4f2f1..f6bc979b1135 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -150,6 +150,11 @@ struct net_bridge_port
 #endif
 };
 
+#define br_port_get_rcu(dev) \
+        ((struct net_bridge_port *) rcu_dereference(dev->rx_handler_data))
+#define br_port_get(dev) ((struct net_bridge_port *) dev->rx_handler_data)
+#define br_port_exists(dev) (dev->priv_flags & IFF_BRIDGE_PORT)
+
 struct br_cpu_netstats {
         unsigned long   rx_packets;
         unsigned long   rx_bytes;
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
index 217bd225a42f..70aecb48fb69 100644
--- a/net/bridge/br_stp_bpdu.c
+++ b/net/bridge/br_stp_bpdu.c
@@ -137,12 +137,13 @@ void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
                 struct net_device *dev)
 {
         const unsigned char *dest = eth_hdr(skb)->h_dest;
-        struct net_bridge_port *p = rcu_dereference(dev->br_port);
+        struct net_bridge_port *p;
         struct net_bridge *br;
         const unsigned char *buf;
 
-        if (!p)
+        if (!br_port_exists(dev))
                 goto err;
+        p = br_port_get_rcu(dev);
 
         if (!pskb_may_pull(skb, 4))
                 goto err;
diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c
index 9e19166ba453..46624bb6d9be 100644
--- a/net/bridge/netfilter/ebt_redirect.c
+++ b/net/bridge/netfilter/ebt_redirect.c
@@ -24,8 +24,9 @@ ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par)
                 return EBT_DROP;
 
         if (par->hooknum != NF_BR_BROUTING)
+                /* rcu_read_lock()ed by nf_hook_slow */
                 memcpy(eth_hdr(skb)->h_dest,
-                       par->in->br_port->br->dev->dev_addr, ETH_ALEN);
+                       br_port_get_rcu(par->in)->br->dev->dev_addr, ETH_ALEN);
         else
                 memcpy(eth_hdr(skb)->h_dest, par->in->dev_addr, ETH_ALEN);
         skb->pkt_type = PACKET_HOST;
diff --git a/net/bridge/netfilter/ebt_ulog.c b/net/bridge/netfilter/ebt_ulog.c
index ae3c7cef1484..26377e96fa1c 100644
--- a/net/bridge/netfilter/ebt_ulog.c
+++ b/net/bridge/netfilter/ebt_ulog.c
@@ -177,8 +177,9 @@ static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb,
         if (in) {
                 strcpy(pm->physindev, in->name);
                 /* If in isn't a bridge, then physindev==indev */
-                if (in->br_port)
-                        strcpy(pm->indev, in->br_port->br->dev->name);
+                if (br_port_exists(in))
+                        /* rcu_read_lock()ed by nf_hook_slow */
+                        strcpy(pm->indev, br_port_get_rcu(in)->br->dev->name);
                 else
                         strcpy(pm->indev, in->name);
         } else
@@ -187,7 +188,8 @@ static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb,
         if (out) {
                 /* If out exists, then out is a bridge port */
                 strcpy(pm->physoutdev, out->name);
-                strcpy(pm->outdev, out->br_port->br->dev->name);
+                /* rcu_read_lock()ed by nf_hook_slow */
+                strcpy(pm->outdev, br_port_get_rcu(out)->br->dev->name);
         } else
                 pm->outdev[0] = pm->physoutdev[0] = '\0';
 
diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 59ca00e40dec..bcc102e3be4d 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -140,11 +140,14 @@ ebt_basic_match(const struct ebt_entry *e, const struct ethhdr *h,
                 return 1;
         if (FWINV2(ebt_dev_check(e->out, out), EBT_IOUT))
                 return 1;
-        if ((!in || !in->br_port) ? 0 : FWINV2(ebt_dev_check(
-           e->logical_in, in->br_port->br->dev), EBT_ILOGICALIN))
+        /* rcu_read_lock()ed by nf_hook_slow */
+        if (in && br_port_exists(in) &&
+            FWINV2(ebt_dev_check(e->logical_in, br_port_get_rcu(in)->br->dev),
+                   EBT_ILOGICALIN))
                 return 1;
-        if ((!out || !out->br_port) ? 0 : FWINV2(ebt_dev_check(
-           e->logical_out, out->br_port->br->dev), EBT_ILOGICALOUT))
+        if (out && br_port_exists(out) &&
+            FWINV2(ebt_dev_check(e->logical_out, br_port_get_rcu(out)->br->dev),
+                   EBT_ILOGICALOUT))
                 return 1;
 
         if (e->bitmask & EBT_SOURCEMAC) {