packet: Do not call fanout_release from atomic contexts

[pandora-kernel.git] / net / packet / af_packet.c

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index a6e5e5e..d60ca88 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1242,6 +1242,8 @@ static void __fanout_link(struct sock *sk, struct packet_sock *po)
        f->arr[f->num_members] = sk;
        smp_wmb();
        f->num_members++;
+       if (f->num_members == 1)
+               dev_add_pack(&f->prot_hook);
        spin_unlock(&f->lock);
 }
 
@@ -1258,6 +1260,8 @@ static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
        BUG_ON(i >= f->num_members);
        f->arr[i] = f->arr[f->num_members - 1];
        f->num_members--;
+       if (f->num_members == 0)
+               __dev_remove_pack(&f->prot_hook);
        spin_unlock(&f->lock);
 }
 
@@ -1325,7 +1329,6 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
                match->prot_hook.func = packet_rcv_fanout;
                match->prot_hook.af_packet_priv = match;
                match->prot_hook.id_match = match_fanout_group;
-               dev_add_pack(&match->prot_hook);
                list_add(&match->list, &fanout_list);
        }
        err = -EINVAL;
@@ -1346,7 +1349,12 @@ out:
        return err;
 }
 
-static void fanout_release(struct sock *sk)
+/* If pkt_sk(sk)->fanout->sk_ref is zero, this function removes
+ * pkt_sk(sk)->fanout from fanout_list and returns pkt_sk(sk)->fanout.
+ * It is the responsibility of the caller to call fanout_release_data() and
+ * free the returned packet_fanout (after synchronize_net())
+ */
+static struct packet_fanout *fanout_release(struct sock *sk)
 {
        struct packet_sock *po = pkt_sk(sk);
        struct packet_fanout *f;
@@ -1356,13 +1364,14 @@ static void fanout_release(struct sock *sk)
        if (f) {
                po->fanout = NULL;
 
-               if (atomic_dec_and_test(&f->sk_ref)) {
+               if (atomic_dec_and_test(&f->sk_ref))
                        list_del(&f->list);
-                       dev_remove_pack(&f->prot_hook);
-                       kfree(f);
-               }
+               else
+                       f = NULL;
        }
        mutex_unlock(&fanout_mutex);
+
+       return f;
 }
 
 static const struct proto_ops packet_ops;
@@ -2385,6 +2394,7 @@ static int packet_release(struct socket *sock)
 {
        struct sock *sk = sock->sk;
        struct packet_sock *po;
+       struct packet_fanout *f;
        struct net *net;
        union tpacket_req_u req_u;
 
@@ -2419,9 +2429,12 @@ static int packet_release(struct socket *sock)
                packet_set_ring(sk, &req_u, 1, 1);
        }
 
-       fanout_release(sk);
+       f = fanout_release(sk);
 
        synchronize_net();
+
+       kfree(f);
+
        /*
         *      Now the socket is dead. No more input will appear.
         */
@@ -3350,7 +3363,6 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
                                                sk->sk_error_report(sk);
                                }
                                if (msg == NETDEV_UNREGISTER) {
-                                       fanout_release(sk);
                                        po->ifindex = -1;
                                        if (po->prot_hook.dev)
                                                dev_put(po->prot_hook.dev);