1 files changed, 144 insertions, 120 deletions

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index 6d126faf145..8e385a0ae60 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -40,6 +40,7 @@
 #define RFCOMM_TTY_MAJOR 216		/* device node major id of the usb/bluetooth.c driver */
 #define RFCOMM_TTY_MINOR 0
 
+static DEFINE_MUTEX(rfcomm_ioctl_mutex);
 static struct tty_driver *rfcomm_tty_driver;
 
 struct rfcomm_dev {
@@ -51,6 +52,8 @@ struct rfcomm_dev {
 	unsigned long		flags;
 	int			err;
 
+	unsigned long		status;		/* don't export to userspace */
+
 	bdaddr_t		src;
 	bdaddr_t		dst;
 	u8			channel;
@@ -67,7 +70,7 @@ struct rfcomm_dev {
 };
 
 static LIST_HEAD(rfcomm_dev_list);
-static DEFINE_SPINLOCK(rfcomm_dev_lock);
+static DEFINE_MUTEX(rfcomm_dev_lock);
 
 static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb);
 static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err);
@@ -82,10 +85,6 @@ static void rfcomm_dev_destruct(struct tty_port *port)
 
 	BT_DBG("dev %p dlc %p", dev, dlc);
 
-	spin_lock(&rfcomm_dev_lock);
-	list_del(&dev->list);
-	spin_unlock(&rfcomm_dev_lock);
-
 	rfcomm_dlc_lock(dlc);
 	/* Detach DLC if it's owned by this dev */
 	if (dlc->owner == dev)
@@ -94,7 +93,12 @@ static void rfcomm_dev_destruct(struct tty_port *port)
 
 	rfcomm_dlc_put(dlc);
 
-	tty_unregister_device(rfcomm_tty_driver, dev->id);
+	if (dev->tty_dev)
+		tty_unregister_device(rfcomm_tty_driver, dev->id);
+
+	mutex_lock(&rfcomm_dev_lock);
+	list_del(&dev->list);
+	mutex_unlock(&rfcomm_dev_lock);
 
 	kfree(dev);
 
@@ -107,8 +111,12 @@ static void rfcomm_dev_destruct(struct tty_port *port)
 static int rfcomm_dev_activate(struct tty_port *port, struct tty_struct *tty)
 {
 	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+	int err;
 
-	return rfcomm_dlc_open(dev->dlc, &dev->src, &dev->dst, dev->channel);
+	err = rfcomm_dlc_open(dev->dlc, &dev->src, &dev->dst, dev->channel);
+	if (err)
+		set_bit(TTY_IO_ERROR, &tty->flags);
+	return err;
 }
 
 /* we block the open until the dlc->state becomes BT_CONNECTED */
@@ -138,7 +146,7 @@ static const struct tty_port_operations rfcomm_port_ops = {
 	.carrier_raised = rfcomm_dev_carrier_raised,
 };
 
-static struct rfcomm_dev *__rfcomm_dev_get(int id)
+static struct rfcomm_dev *__rfcomm_dev_lookup(int id)
 {
 	struct rfcomm_dev *dev;
 
@@ -153,36 +161,41 @@ static struct rfcomm_dev *rfcomm_dev_get(int id)
 {
 	struct rfcomm_dev *dev;
 
-	spin_lock(&rfcomm_dev_lock);
+	mutex_lock(&rfcomm_dev_lock);
 
-	dev = __rfcomm_dev_get(id);
+	dev = __rfcomm_dev_lookup(id);
 
-	if (dev) {
-		if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags))
-			dev = NULL;
-		else
-			tty_port_get(&dev->port);
-	}
+	if (dev && !tty_port_get(&dev->port))
+		dev = NULL;
 
-	spin_unlock(&rfcomm_dev_lock);
+	mutex_unlock(&rfcomm_dev_lock);
 
 	return dev;
 }
 
-static struct device *rfcomm_get_device(struct rfcomm_dev *dev)
+static void rfcomm_reparent_device(struct rfcomm_dev *dev)
 {
 	struct hci_dev *hdev;
 	struct hci_conn *conn;
 
 	hdev = hci_get_route(&dev->dst, &dev->src);
 	if (!hdev)
-		return NULL;
+		return;
 
+	/* The lookup results are unsafe to access without the
+	 * hci device lock (FIXME: why is this not documented?)
+	 */
+	hci_dev_lock(hdev);
 	conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, &dev->dst);
 
-	hci_dev_put(hdev);
+	/* Just because the acl link is in the hash table is no
+	 * guarantee the sysfs device has been added ...
+	 */
+	if (conn && device_is_registered(&conn->dev))
+		device_move(dev->tty_dev, &conn->dev, DPM_ORDER_DEV_AFTER_PARENT);
 
-	return conn ? &conn->dev : NULL;
+	hci_dev_unlock(hdev);
+	hci_dev_put(hdev);
 }
 
 static ssize_t show_address(struct device *tty_dev, struct device_attribute *attr, char *buf)
@@ -200,19 +213,18 @@ static ssize_t show_channel(struct device *tty_dev, struct device_attribute *att
 static DEVICE_ATTR(address, S_IRUGO, show_address, NULL);
 static DEVICE_ATTR(channel, S_IRUGO, show_channel, NULL);
 
-static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc)
+static struct rfcomm_dev *__rfcomm_dev_add(struct rfcomm_dev_req *req,
+					   struct rfcomm_dlc *dlc)
 {
 	struct rfcomm_dev *dev, *entry;
 	struct list_head *head = &rfcomm_dev_list;
 	int err = 0;
 
-	BT_DBG("id %d channel %d", req->dev_id, req->channel);
-
 	dev = kzalloc(sizeof(struct rfcomm_dev), GFP_KERNEL);
 	if (!dev)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	spin_lock(&rfcomm_dev_lock);
+	mutex_lock(&rfcomm_dev_lock);
 
 	if (req->dev_id < 0) {
 		dev->id = 0;
@@ -293,22 +305,37 @@ static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc)
 	   holds reference to this module. */
 	__module_get(THIS_MODULE);
 
+	mutex_unlock(&rfcomm_dev_lock);
+	return dev;
+
 out:
-	spin_unlock(&rfcomm_dev_lock);
+	mutex_unlock(&rfcomm_dev_lock);
+	kfree(dev);
+	return ERR_PTR(err);
+}
+
+static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc)
+{
+	struct rfcomm_dev *dev;
+	struct device *tty;
 
-	if (err < 0)
-		goto free;
+	BT_DBG("id %d channel %d", req->dev_id, req->channel);
 
-	dev->tty_dev = tty_port_register_device(&dev->port, rfcomm_tty_driver,
+	dev = __rfcomm_dev_add(req, dlc);
+	if (IS_ERR(dev)) {
+		rfcomm_dlc_put(dlc);
+		return PTR_ERR(dev);
+	}
+
+	tty = tty_port_register_device(&dev->port, rfcomm_tty_driver,
 			dev->id, NULL);
-	if (IS_ERR(dev->tty_dev)) {
-		err = PTR_ERR(dev->tty_dev);
-		spin_lock(&rfcomm_dev_lock);
-		list_del(&dev->list);
-		spin_unlock(&rfcomm_dev_lock);
-		goto free;
+	if (IS_ERR(tty)) {
+		tty_port_put(&dev->port);
+		return PTR_ERR(tty);
 	}
 
+	dev->tty_dev = tty;
+	rfcomm_reparent_device(dev);
 	dev_set_drvdata(dev->tty_dev, dev);
 
 	if (device_create_file(dev->tty_dev, &dev_attr_address) < 0)
@@ -318,24 +345,23 @@ out:
 		BT_ERR("Failed to create channel attribute");
 
 	return dev->id;
-
-free:
-	kfree(dev);
-	return err;
 }
 
 /* ---- Send buffer ---- */
-static inline unsigned int rfcomm_room(struct rfcomm_dlc *dlc)
+static inline unsigned int rfcomm_room(struct rfcomm_dev *dev)
 {
-	/* We can't let it be zero, because we don't get a callback
-	   when tx_credits becomes nonzero, hence we'd never wake up */
-	return dlc->mtu * (dlc->tx_credits?:1);
+	struct rfcomm_dlc *dlc = dev->dlc;
+
+	/* Limit the outstanding number of packets not yet sent to 40 */
+	int pending = 40 - atomic_read(&dev->wmem_alloc);
+
+	return max(0, pending) * dlc->mtu;
 }
 
 static void rfcomm_wfree(struct sk_buff *skb)
 {
 	struct rfcomm_dev *dev = (void *) skb->sk;
-	atomic_sub(skb->truesize, &dev->wmem_alloc);
+	atomic_dec(&dev->wmem_alloc);
 	if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags))
 		tty_port_tty_wakeup(&dev->port);
 	tty_port_put(&dev->port);
@@ -344,28 +370,24 @@ static void rfcomm_wfree(struct sk_buff *skb)
 static void rfcomm_set_owner_w(struct sk_buff *skb, struct rfcomm_dev *dev)
 {
 	tty_port_get(&dev->port);
-	atomic_add(skb->truesize, &dev->wmem_alloc);
+	atomic_inc(&dev->wmem_alloc);
 	skb->sk = (void *) dev;
 	skb->destructor = rfcomm_wfree;
 }
 
 static struct sk_buff *rfcomm_wmalloc(struct rfcomm_dev *dev, unsigned long size, gfp_t priority)
 {
-	if (atomic_read(&dev->wmem_alloc) < rfcomm_room(dev->dlc)) {
-		struct sk_buff *skb = alloc_skb(size, priority);
-		if (skb) {
-			rfcomm_set_owner_w(skb, dev);
-			return skb;
-		}
-	}
-	return NULL;
+	struct sk_buff *skb = alloc_skb(size, priority);
+	if (skb)
+		rfcomm_set_owner_w(skb, dev);
+	return skb;
 }
 
 /* ---- Device IOCTLs ---- */
 
 #define NOCAP_FLAGS ((1 << RFCOMM_REUSE_DLC) | (1 << RFCOMM_RELEASE_ONHUP))
 
-static int rfcomm_create_dev(struct sock *sk, void __user *arg)
+static int __rfcomm_create_dev(struct sock *sk, void __user *arg)
 {
 	struct rfcomm_dev_req req;
 	struct rfcomm_dlc *dlc;
@@ -387,16 +409,22 @@ static int rfcomm_create_dev(struct sock *sk, void __user *arg)
 		dlc = rfcomm_pi(sk)->dlc;
 		rfcomm_dlc_hold(dlc);
 	} else {
+		/* Validate the channel is unused */
+		dlc = rfcomm_dlc_exists(&req.src, &req.dst, req.channel);
+		if (IS_ERR(dlc))
+			return PTR_ERR(dlc);
+		else if (dlc) {
+			rfcomm_dlc_put(dlc);
+			return -EBUSY;
+		}
 		dlc = rfcomm_dlc_alloc(GFP_KERNEL);
 		if (!dlc)
 			return -ENOMEM;
 	}
 
 	id = rfcomm_dev_add(&req, dlc);
-	if (id < 0) {
-		rfcomm_dlc_put(dlc);
+	if (id < 0)
 		return id;
-	}
 
 	if (req.flags & (1 << RFCOMM_REUSE_DLC)) {
 		/* DLC is now used by device.
@@ -407,7 +435,7 @@ static int rfcomm_create_dev(struct sock *sk, void __user *arg)
 	return id;
 }
 
-static int rfcomm_release_dev(void __user *arg)
+static int __rfcomm_release_dev(void __user *arg)
 {
 	struct rfcomm_dev_req req;
 	struct rfcomm_dev *dev;
@@ -427,6 +455,12 @@ static int rfcomm_release_dev(void __user *arg)
 		return -EPERM;
 	}
 
+	/* only release once */
+	if (test_and_set_bit(RFCOMM_DEV_RELEASED, &dev->status)) {
+		tty_port_put(&dev->port);
+		return -EALREADY;
+	}
+
 	if (req.flags & (1 << RFCOMM_HANGUP_NOW))
 		rfcomm_dlc_close(dev->dlc, 0);
 
@@ -437,13 +471,35 @@ static int rfcomm_release_dev(void __user *arg)
 		tty_kref_put(tty);
 	}
 
-	if (!test_and_set_bit(RFCOMM_TTY_RELEASED, &dev->flags))
+	if (!test_bit(RFCOMM_TTY_OWNED, &dev->status))
 		tty_port_put(&dev->port);
 
 	tty_port_put(&dev->port);
 	return 0;
 }
 
+static int rfcomm_create_dev(struct sock *sk, void __user *arg)
+{
+	int ret;
+
+	mutex_lock(&rfcomm_ioctl_mutex);
+	ret = __rfcomm_create_dev(sk, arg);
+	mutex_unlock(&rfcomm_ioctl_mutex);
+
+	return ret;
+}
+
+static int rfcomm_release_dev(void __user *arg)
+{
+	int ret;
+
+	mutex_lock(&rfcomm_ioctl_mutex);
+	ret = __rfcomm_release_dev(arg);
+	mutex_unlock(&rfcomm_ioctl_mutex);
+
+	return ret;
+}
+
 static int rfcomm_get_dev_list(void __user *arg)
 {
 	struct rfcomm_dev *dev;
@@ -468,10 +524,10 @@ static int rfcomm_get_dev_list(void __user *arg)
 
 	di = dl->dev_info;
 
-	spin_lock(&rfcomm_dev_lock);
+	mutex_lock(&rfcomm_dev_lock);
 
 	list_for_each_entry(dev, &rfcomm_dev_list, list) {
-		if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags))
+		if (!tty_port_get(&dev->port))
 			continue;
 		(di + n)->id      = dev->id;
 		(di + n)->flags   = dev->flags;
@@ -479,11 +535,12 @@ static int rfcomm_get_dev_list(void __user *arg)
 		(di + n)->channel = dev->channel;
 		bacpy(&(di + n)->src, &dev->src);
 		bacpy(&(di + n)->dst, &dev->dst);
+		tty_port_put(&dev->port);
 		if (++n >= dev_num)
 			break;
 	}
 
-	spin_unlock(&rfcomm_dev_lock);
+	mutex_unlock(&rfcomm_dev_lock);
 
 	dl->dev_num = n;
 	size = sizeof(*dl) + n * sizeof(*di);
@@ -569,7 +626,6 @@ static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb)
 static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
 {
 	struct rfcomm_dev *dev = dlc->owner;
-	struct tty_struct *tty;
 	if (!dev)
 		return;
 
@@ -577,42 +633,11 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
 
 	dev->err = err;
 	if (dlc->state == BT_CONNECTED) {
-		device_move(dev->tty_dev, rfcomm_get_device(dev),
-			    DPM_ORDER_DEV_AFTER_PARENT);
+		rfcomm_reparent_device(dev);
 
 		wake_up_interruptible(&dev->port.open_wait);
-	} else if (dlc->state == BT_CLOSED) {
-		tty = tty_port_tty_get(&dev->port);
-		if (!tty) {
-			if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
-				/* Drop DLC lock here to avoid deadlock
-				 * 1. rfcomm_dev_get will take rfcomm_dev_lock
-				 *    but in rfcomm_dev_add there's lock order:
-				 *    rfcomm_dev_lock -> dlc lock
-				 * 2. tty_port_put will deadlock if it's
-				 *    the last reference
-				 *
-				 * FIXME: when we release the lock anything
-				 * could happen to dev, even its destruction
-				 */
-				rfcomm_dlc_unlock(dlc);
-				if (rfcomm_dev_get(dev->id) == NULL) {
-					rfcomm_dlc_lock(dlc);
-					return;
-				}
-
-				if (!test_and_set_bit(RFCOMM_TTY_RELEASED,
-						      &dev->flags))
-					tty_port_put(&dev->port);
-
-				tty_port_put(&dev->port);
-				rfcomm_dlc_lock(dlc);
-			}
-		} else {
-			tty_hangup(tty);
-			tty_kref_put(tty);
-		}
-	}
+	} else if (dlc->state == BT_CLOSED)
+		tty_port_tty_hangup(&dev->port, false);
 }
 
 static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig)
@@ -701,10 +726,22 @@ static int rfcomm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
 
 	/* install the tty_port */
 	err = tty_port_install(&dev->port, driver, tty);
-	if (err)
+	if (err) {
 		rfcomm_tty_cleanup(tty);
+		return err;
+	}
 
-	return err;
+	/* take over the tty_port reference if the port was created with the
+	 * flag RFCOMM_RELEASE_ONHUP. This will force the release of the port
+	 * when the last process closes the tty. The behaviour is expected by
+	 * userspace.
+	 */
+	if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
+		set_bit(RFCOMM_TTY_OWNED, &dev->status);
+		tty_port_put(&dev->port);
+	}
+
+	return 0;
 }
 
 static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
@@ -748,7 +785,7 @@ static int rfcomm_tty_write(struct tty_struct *tty, const unsigned char *buf, in
 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
 	struct rfcomm_dlc *dlc = dev->dlc;
 	struct sk_buff *skb;
-	int err = 0, sent = 0, size;
+	int sent = 0, size;
 
 	BT_DBG("tty %p count %d", tty, count);
 
@@ -756,7 +793,6 @@ static int rfcomm_tty_write(struct tty_struct *tty, const unsigned char *buf, in
 		size = min_t(uint, count, dlc->mtu);
 
 		skb = rfcomm_wmalloc(dev, size + RFCOMM_SKB_RESERVE, GFP_ATOMIC);
-
 		if (!skb)
 			break;
 
@@ -764,32 +800,24 @@ static int rfcomm_tty_write(struct tty_struct *tty, const unsigned char *buf, in
 
 		memcpy(skb_put(skb, size), buf + sent, size);
 
-		err = rfcomm_dlc_send(dlc, skb);
-		if (err < 0) {
-			kfree_skb(skb);
-			break;
-		}
+		rfcomm_dlc_send_noerror(dlc, skb);
 
 		sent  += size;
 		count -= size;
 	}
 
-	return sent ? sent : err;
+	return sent;
 }
 
 static int rfcomm_tty_write_room(struct tty_struct *tty)
 {
 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
-	int room;
+	int room = 0;
 
-	BT_DBG("tty %p", tty);
+	if (dev && dev->dlc)
+		room = rfcomm_room(dev);
 
-	if (!dev || !dev->dlc)
-		return 0;
-
-	room = rfcomm_room(dev->dlc) - atomic_read(&dev->wmem_alloc);
-	if (room < 0)
-		room = 0;
+	BT_DBG("tty %p room %d", tty, room);
 
 	return room;
 }
@@ -1041,10 +1069,6 @@ static void rfcomm_tty_hangup(struct tty_struct *tty)
 	BT_DBG("tty %p dev %p", tty, dev);
 
 	tty_port_hangup(&dev->port);
-
-	if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags) &&
-	    !test_and_set_bit(RFCOMM_TTY_RELEASED, &dev->flags))
-		tty_port_put(&dev->port);
 }
 
 static int rfcomm_tty_tiocmget(struct tty_struct *tty)