[Bluetooth] Add locking for bt_proto array manipulation

The bt_proto array needs to be protected by some kind of locking to
prevent a race condition between bt_sock_create and bt_sock_register.

And in addition all calls to sk_alloc need to be made GFP_ATOMIC now.
Signed-off-by: Masatake YAMATO <jet@gyve.org>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/af_bluetooth.c

@@ -53,36 +53,51 @@
 /* Bluetooth sockets */
 #define BT_MAX_PROTO	8
 static struct net_proto_family *bt_proto[BT_MAX_PROTO];
+static DEFINE_RWLOCK(bt_proto_lock);
 
 int bt_sock_register(int proto, struct net_proto_family *ops)
 {
+	int err = 0;
+
 	if (proto < 0 || proto >= BT_MAX_PROTO)
 		return -EINVAL;
 
+	write_lock(&bt_proto_lock);
+
 	if (bt_proto[proto])
-		return -EEXIST;
+		err = -EEXIST;
+	else
+		bt_proto[proto] = ops;
 
-	bt_proto[proto] = ops;
-	return 0;
+	write_unlock(&bt_proto_lock);
+
+	return err;
 }
 EXPORT_SYMBOL(bt_sock_register);
 
 int bt_sock_unregister(int proto)
 {
+	int err = 0;
+
 	if (proto < 0 || proto >= BT_MAX_PROTO)
 		return -EINVAL;
 
+	write_lock(&bt_proto_lock);
+
 	if (!bt_proto[proto])
-		return -ENOENT;
+		err = -ENOENT;
+	else
+		bt_proto[proto] = NULL;
 
-	bt_proto[proto] = NULL;
-	return 0;
+	write_unlock(&bt_proto_lock);
+
+	return err;
 }
 EXPORT_SYMBOL(bt_sock_unregister);
 
 static int bt_sock_create(struct socket *sock, int proto)
 {
-	int err = 0;
+	int err;
 
 	if (proto < 0 || proto >= BT_MAX_PROTO)
 		return -EINVAL;
@@ -92,11 +107,18 @@ static int bt_sock_create(struct socket *sock, int proto)
 		request_module("bt-proto-%d", proto);
 	}
 #endif
+
 	err = -EPROTONOSUPPORT;
+
+	read_lock(&bt_proto_lock);
+
 	if (bt_proto[proto] && try_module_get(bt_proto[proto]->owner)) {
 		err = bt_proto[proto]->create(sock, proto);
 		module_put(bt_proto[proto]->owner);
 	}
+
+	read_unlock(&bt_proto_lock);
+
 	return err; 
 }
 

net/bluetooth/bnep/sock.c

@@ -214,7 +214,7 @@ static int bnep_sock_create(struct socket *sock, int protocol)
 	if (sock->type != SOCK_RAW)
 		return -ESOCKTNOSUPPORT;
 
-	sk = sk_alloc(PF_BLUETOOTH, GFP_KERNEL, &bnep_proto, 1);
+	sk = sk_alloc(PF_BLUETOOTH, GFP_ATOMIC, &bnep_proto, 1);
 	if (!sk)
 		return -ENOMEM;
 

net/bluetooth/cmtp/sock.c

@@ -205,7 +205,7 @@ static int cmtp_sock_create(struct socket *sock, int protocol)
 	if (sock->type != SOCK_RAW)
 		return -ESOCKTNOSUPPORT;
 
-	sk = sk_alloc(PF_BLUETOOTH, GFP_KERNEL, &cmtp_proto, 1);
+	sk = sk_alloc(PF_BLUETOOTH, GFP_ATOMIC, &cmtp_proto, 1);
 	if (!sk)
 		return -ENOMEM;
 

net/bluetooth/hci_sock.c

@@ -618,7 +618,7 @@ static int hci_sock_create(struct socket *sock, int protocol)
 
 	sock->ops = &hci_sock_ops;
 
-	sk = sk_alloc(PF_BLUETOOTH, GFP_KERNEL, &hci_sk_proto, 1);
+	sk = sk_alloc(PF_BLUETOOTH, GFP_ATOMIC, &hci_sk_proto, 1);
 	if (!sk)
 		return -ENOMEM;
 

net/bluetooth/hidp/sock.c

@@ -256,7 +256,7 @@ static int hidp_sock_create(struct socket *sock, int protocol)
 	if (sock->type != SOCK_RAW)
 		return -ESOCKTNOSUPPORT;
 
-	sk = sk_alloc(PF_BLUETOOTH, GFP_KERNEL, &hidp_proto, 1);
+	sk = sk_alloc(PF_BLUETOOTH, GFP_ATOMIC, &hidp_proto, 1);
 	if (!sk)
 		return -ENOMEM;
 

net/bluetooth/l2cap.c

@@ -559,7 +559,7 @@ static int l2cap_sock_create(struct socket *sock, int protocol)
 
 	sock->ops = &l2cap_sock_ops;
 
-	sk = l2cap_sock_alloc(sock, protocol, GFP_KERNEL);
+	sk = l2cap_sock_alloc(sock, protocol, GFP_ATOMIC);
 	if (!sk)
 		return -ENOMEM;
 

net/bluetooth/rfcomm/sock.c

@@ -336,7 +336,8 @@ static int rfcomm_sock_create(struct socket *sock, int protocol)
 
 	sock->ops = &rfcomm_sock_ops;
 
-	if (!(sk = rfcomm_sock_alloc(sock, protocol, GFP_KERNEL)))
+	sk = rfcomm_sock_alloc(sock, protocol, GFP_ATOMIC);
+	if (!sk)
 		return -ENOMEM;
 
 	rfcomm_sock_init(sk, NULL);

net/bluetooth/sco.c

@@ -452,7 +452,8 @@ static int sco_sock_create(struct socket *sock, int protocol)
 
 	sock->ops = &sco_sock_ops;
 
-	if (!(sk = sco_sock_alloc(sock, protocol, GFP_KERNEL)))
+	sk = sco_sock_alloc(sock, protocol, GFP_ATOMIC);
+	if (!sk)
 		return -ENOMEM;
 
 	sco_sock_init(sk, NULL);