1 files changed, 42 insertions, 27 deletions

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index ac27c86ef6d1..88cfbc189558 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -237,6 +237,30 @@ struct packet_skb_cb {
 static void __fanout_unlink(struct sock *sk, struct packet_sock *po);
 static void __fanout_link(struct sock *sk, struct packet_sock *po);
 
+static struct net_device *packet_cached_dev_get(struct packet_sock *po)
+{
+        struct net_device *dev;
+
+        rcu_read_lock();
+        dev = rcu_dereference(po->cached_dev);
+        if (likely(dev))
+                dev_hold(dev);
+        rcu_read_unlock();
+
+        return dev;
+}
+
+static void packet_cached_dev_assign(struct packet_sock *po,
+                                     struct net_device *dev)
+{
+        rcu_assign_pointer(po->cached_dev, dev);
+}
+
+static void packet_cached_dev_reset(struct packet_sock *po)
+{
+        RCU_INIT_POINTER(po->cached_dev, NULL);
+}
+
 /* register_prot_hook must be invoked with the po->bind_lock held,
  * or from a context in which asynchronous accesses to the packet
  * socket is not possible (packet_create()).
@@ -246,12 +270,10 @@ static void register_prot_hook(struct sock *sk)
         struct packet_sock *po = pkt_sk(sk);
 
         if (!po->running) {
-                if (po->fanout) {
+                if (po->fanout)
                         __fanout_link(sk, po);
-                } else {
+                else
                         dev_add_pack(&po->prot_hook);
-                        rcu_assign_pointer(po->cached_dev, po->prot_hook.dev);
-                }
 
                 sock_hold(sk);
                 po->running = 1;
@@ -270,12 +292,11 @@ static void __unregister_prot_hook(struct sock *sk, bool sync)
         struct packet_sock *po = pkt_sk(sk);
 
         po->running = 0;
-        if (po->fanout) {
+
+        if (po->fanout)
                 __fanout_unlink(sk, po);
-        } else {
+        else
                 __dev_remove_pack(&po->prot_hook);
-                RCU_INIT_POINTER(po->cached_dev, NULL);
-        }
 
         __sock_put(sk);
 
@@ -439,9 +460,9 @@ static void prb_shutdown_retire_blk_timer(struct packet_sock *po,
 
         pkc = tx_ring ? &po->tx_ring.prb_bdqc : &po->rx_ring.prb_bdqc;
 
-        spin_lock(&rb_queue->lock);
+        spin_lock_bh(&rb_queue->lock);
         pkc->delete_blk_timer = 1;
-        spin_unlock(&rb_queue->lock);
+        spin_unlock_bh(&rb_queue->lock);
 
         prb_del_retire_blk_timer(pkc);
 }
@@ -2059,19 +2080,6 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
         return tp_len;
 }
 
-static struct net_device *packet_cached_dev_get(struct packet_sock *po)
-{
-        struct net_device *dev;
-
-        rcu_read_lock();
-        dev = rcu_dereference(po->cached_dev);
-        if (dev)
-                dev_hold(dev);
-        rcu_read_unlock();
-
-        return dev;
-}
-
 static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
 {
         struct sk_buff *skb;
@@ -2088,7 +2096,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
 
         mutex_lock(&po->pg_vec_lock);
 
-        if (saddr == NULL) {
+        if (likely(saddr == NULL)) {
                 dev     = packet_cached_dev_get(po);
                 proto   = po->num;
                 addr    = NULL;
@@ -2242,7 +2250,7 @@ static int packet_snd(struct socket *sock,
          *      Get and verify the address.
          */
 
-        if (saddr == NULL) {
+        if (likely(saddr == NULL)) {
                 dev     = packet_cached_dev_get(po);
                 proto   = po->num;
                 addr    = NULL;
@@ -2451,6 +2459,8 @@ static int packet_release(struct socket *sock)
 
         spin_lock(&po->bind_lock);
         unregister_prot_hook(sk, false);
+        packet_cached_dev_reset(po);
+
         if (po->prot_hook.dev) {
                 dev_put(po->prot_hook.dev);
                 po->prot_hook.dev = NULL;
@@ -2506,14 +2516,17 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc
 
         spin_lock(&po->bind_lock);
         unregister_prot_hook(sk, true);
+
         po->num = protocol;
         po->prot_hook.type = protocol;
         if (po->prot_hook.dev)
                 dev_put(po->prot_hook.dev);
-        po->prot_hook.dev = dev;
 
+        po->prot_hook.dev = dev;
         po->ifindex = dev ? dev->ifindex : 0;
 
+        packet_cached_dev_assign(po, dev);
+
         if (protocol == 0)
                 goto out_unlock;
 
@@ -2626,7 +2639,8 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
         po = pkt_sk(sk);
         sk->sk_family = PF_PACKET;
         po->num = proto;
-        RCU_INIT_POINTER(po->cached_dev, NULL);
+
+        packet_cached_dev_reset(po);
 
         sk->sk_destruct = packet_sock_destruct;
         sk_refcnt_debug_inc(sk);
@@ -3337,6 +3351,7 @@ static int packet_notifier(struct notifier_block *this,
                                                 sk->sk_error_report(sk);
                                 }
                                 if (msg == NETDEV_UNREGISTER) {
+                                        packet_cached_dev_reset(po);
                                         po->ifindex = -1;
                                         if (po->prot_hook.dev)
                                                 dev_put(po->prot_hook.dev);