af_packet: lock imbalance

fanout_add() might return with fanout_mutex held.

Reduce indentation level while we are at it
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

@@ -589,11 +589,14 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
 			break;
 		}
 	}
+	err = -EINVAL;
 	if (match && match->defrag != defrag)
-		return -EINVAL;
+		goto out;
 	if (!match) {
+		err = -ENOMEM;
 		match = kzalloc(sizeof(*match), GFP_KERNEL);
-		if (match) {
+		if (!match)
+			goto out;
 		write_pnet(&match->net, sock_net(sk));
 		match->id = id;
 		match->type = type;
@@ -609,9 +612,6 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
 		dev_add_pack(&match->prot_hook);
 		list_add(&match->list, &fanout_list);
 	}
-	}
-	err = -ENOMEM;
-	if (match) {
 	err = -EINVAL;
 	if (match->type == type &&
 	    match->prot_hook.type == po->prot_hook.type &&
@@ -625,7 +625,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
 			err = 0;
 		}
 	}
-	}
+out:
 	mutex_unlock(&fanout_mutex);
 	return err;
 }