1 files changed, 126 insertions, 145 deletions

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index b6e44ad6cca6..6d126faf145f 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -58,7 +58,6 @@ struct rfcomm_dev {
 	uint			modem_status;
 
 	struct rfcomm_dlc	*dlc;
-	wait_queue_head_t       wait;
 
 	struct device		*tty_dev;
 
@@ -76,13 +75,6 @@ static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig);
 
 /* ---- Device functions ---- */
 
-/*
- * The reason this isn't actually a race, as you no doubt have a little voice
- * screaming at you in your head, is that the refcount should never actually
- * reach zero unless the device has already been taken off the list, in
- * rfcomm_dev_del(). And if that's not true, we'll hit the BUG() in
- * rfcomm_dev_destruct() anyway.
- */
 static void rfcomm_dev_destruct(struct tty_port *port)
 {
 	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
@@ -90,10 +82,9 @@ static void rfcomm_dev_destruct(struct tty_port *port)
 
 	BT_DBG("dev %p dlc %p", dev, dlc);
 
-	/* Refcount should only hit zero when called from rfcomm_dev_del()
-	   which will have taken us off the list. Everything else are
-	   refcounting bugs. */
-	BUG_ON(!list_empty(&dev->list));
+	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 */
@@ -112,8 +103,39 @@ static void rfcomm_dev_destruct(struct tty_port *port)
 	module_put(THIS_MODULE);
 }
 
+/* device-specific initialization: open the dlc */
+static int rfcomm_dev_activate(struct tty_port *port, struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+
+	return rfcomm_dlc_open(dev->dlc, &dev->src, &dev->dst, dev->channel);
+}
+
+/* we block the open until the dlc->state becomes BT_CONNECTED */
+static int rfcomm_dev_carrier_raised(struct tty_port *port)
+{
+	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+
+	return (dev->dlc->state == BT_CONNECTED);
+}
+
+/* device-specific cleanup: close the dlc */
+static void rfcomm_dev_shutdown(struct tty_port *port)
+{
+	struct rfcomm_dev *dev = container_of(port, struct rfcomm_dev, port);
+
+	if (dev->tty_dev->parent)
+		device_move(dev->tty_dev, NULL, DPM_ORDER_DEV_LAST);
+
+	/* close the dlc */
+	rfcomm_dlc_close(dev->dlc, 0);
+}
+
 static const struct tty_port_operations rfcomm_port_ops = {
 	.destruct = rfcomm_dev_destruct,
+	.activate = rfcomm_dev_activate,
+	.shutdown = rfcomm_dev_shutdown,
+	.carrier_raised = rfcomm_dev_carrier_raised,
 };
 
 static struct rfcomm_dev *__rfcomm_dev_get(int id)
@@ -236,7 +258,6 @@ static int rfcomm_dev_add(struct rfcomm_dev_req *req, struct rfcomm_dlc *dlc)
 
 	tty_port_init(&dev->port);
 	dev->port.ops = &rfcomm_port_ops;
-	init_waitqueue_head(&dev->wait);
 
 	skb_queue_head_init(&dev->pending);
 
@@ -282,7 +303,9 @@ out:
 			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;
 	}
 
@@ -301,27 +324,6 @@ free:
 	return err;
 }
 
-static void rfcomm_dev_del(struct rfcomm_dev *dev)
-{
-	unsigned long flags;
-	BT_DBG("dev %p", dev);
-
-	BUG_ON(test_and_set_bit(RFCOMM_TTY_RELEASED, &dev->flags));
-
-	spin_lock_irqsave(&dev->port.lock, flags);
-	if (dev->port.count > 0) {
-		spin_unlock_irqrestore(&dev->port.lock, flags);
-		return;
-	}
-	spin_unlock_irqrestore(&dev->port.lock, flags);
-
-	spin_lock(&rfcomm_dev_lock);
-	list_del_init(&dev->list);
-	spin_unlock(&rfcomm_dev_lock);
-
-	tty_port_put(&dev->port);
-}
-
 /* ---- Send buffer ---- */
 static inline unsigned int rfcomm_room(struct rfcomm_dlc *dlc)
 {
@@ -333,10 +335,9 @@ static inline unsigned int rfcomm_room(struct rfcomm_dlc *dlc)
 static void rfcomm_wfree(struct sk_buff *skb)
 {
 	struct rfcomm_dev *dev = (void *) skb->sk;
-	struct tty_struct *tty = dev->port.tty;
 	atomic_sub(skb->truesize, &dev->wmem_alloc);
-	if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags) && tty)
-		tty_wakeup(tty);
+	if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags))
+		tty_port_tty_wakeup(&dev->port);
 	tty_port_put(&dev->port);
 }
 
@@ -410,6 +411,7 @@ static int rfcomm_release_dev(void __user *arg)
 {
 	struct rfcomm_dev_req req;
 	struct rfcomm_dev *dev;
+	struct tty_struct *tty;
 
 	if (copy_from_user(&req, arg, sizeof(req)))
 		return -EFAULT;
@@ -429,11 +431,15 @@ static int rfcomm_release_dev(void __user *arg)
 		rfcomm_dlc_close(dev->dlc, 0);
 
 	/* Shut down TTY synchronously before freeing rfcomm_dev */
-	if (dev->port.tty)
-		tty_vhangup(dev->port.tty);
+	tty = tty_port_tty_get(&dev->port);
+	if (tty) {
+		tty_vhangup(tty);
+		tty_kref_put(tty);
+	}
+
+	if (!test_and_set_bit(RFCOMM_TTY_RELEASED, &dev->flags))
+		tty_port_put(&dev->port);
 
-	if (!test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags))
-		rfcomm_dev_del(dev);
 	tty_port_put(&dev->port);
 	return 0;
 }
@@ -563,16 +569,21 @@ 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;
 
 	BT_DBG("dlc %p dev %p err %d", dlc, dev, err);
 
 	dev->err = err;
-	wake_up_interruptible(&dev->wait);
+	if (dlc->state == BT_CONNECTED) {
+		device_move(dev->tty_dev, rfcomm_get_device(dev),
+			    DPM_ORDER_DEV_AFTER_PARENT);
 
-	if (dlc->state == BT_CLOSED) {
-		if (!dev->port.tty) {
+		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
@@ -580,6 +591,9 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
 				 *    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) {
@@ -587,12 +601,17 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
 					return;
 				}
 
-				rfcomm_dev_del(dev);
+				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(dev->port.tty);
+		} else {
+			tty_hangup(tty);
+			tty_kref_put(tty);
+		}
 	}
 }
 
@@ -604,10 +623,8 @@ static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig)
 
 	BT_DBG("dlc %p dev %p v24_sig 0x%02x", dlc, dev, v24_sig);
 
-	if ((dev->modem_status & TIOCM_CD) && !(v24_sig & RFCOMM_V24_DV)) {
-		if (dev->port.tty && !C_CLOCAL(dev->port.tty))
-			tty_hangup(dev->port.tty);
-	}
+	if ((dev->modem_status & TIOCM_CD) && !(v24_sig & RFCOMM_V24_DV))
+		tty_port_tty_hangup(&dev->port, true);
 
 	dev->modem_status =
 		((v24_sig & RFCOMM_V24_RTC) ? (TIOCM_DSR | TIOCM_DTR) : 0) |
@@ -638,124 +655,92 @@ static void rfcomm_tty_copy_pending(struct rfcomm_dev *dev)
 		tty_flip_buffer_push(&dev->port);
 }
 
-static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
+/* do the reverse of install, clearing the tty fields and releasing the
+ * reference to tty_port
+ */
+static void rfcomm_tty_cleanup(struct tty_struct *tty)
 {
-	DECLARE_WAITQUEUE(wait, current);
-	struct rfcomm_dev *dev;
-	struct rfcomm_dlc *dlc;
-	unsigned long flags;
-	int err, id;
+	struct rfcomm_dev *dev = tty->driver_data;
 
-	id = tty->index;
+	clear_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
 
-	BT_DBG("tty %p id %d", tty, id);
+	rfcomm_dlc_lock(dev->dlc);
+	tty->driver_data = NULL;
+	rfcomm_dlc_unlock(dev->dlc);
 
-	/* We don't leak this refcount. For reasons which are not entirely
-	   clear, the TTY layer will call our ->close() method even if the
-	   open fails. We decrease the refcount there, and decreasing it
-	   here too would cause breakage. */
-	dev = rfcomm_dev_get(id);
-	if (!dev)
-		return -ENODEV;
+	/*
+	 * purge the dlc->tx_queue to avoid circular dependencies
+	 * between dev and dlc
+	 */
+	skb_queue_purge(&dev->dlc->tx_queue);
 
-	BT_DBG("dev %p dst %pMR channel %d opened %d", dev, &dev->dst,
-	       dev->channel, dev->port.count);
+	tty_port_put(&dev->port);
+}
 
-	spin_lock_irqsave(&dev->port.lock, flags);
-	if (++dev->port.count > 1) {
-		spin_unlock_irqrestore(&dev->port.lock, flags);
-		return 0;
-	}
-	spin_unlock_irqrestore(&dev->port.lock, flags);
+/* we acquire the tty_port reference since it's here the tty is first used
+ * by setting the termios. We also populate the driver_data field and install
+ * the tty port
+ */
+static int rfcomm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+	struct rfcomm_dev *dev;
+	struct rfcomm_dlc *dlc;
+	int err;
+
+	dev = rfcomm_dev_get(tty->index);
+	if (!dev)
+		return -ENODEV;
 
 	dlc = dev->dlc;
 
 	/* Attach TTY and open DLC */
-
 	rfcomm_dlc_lock(dlc);
 	tty->driver_data = dev;
-	dev->port.tty = tty;
 	rfcomm_dlc_unlock(dlc);
 	set_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
 
-	err = rfcomm_dlc_open(dlc, &dev->src, &dev->dst, dev->channel);
-	if (err < 0)
-		return err;
-
-	/* Wait for DLC to connect */
-	add_wait_queue(&dev->wait, &wait);
-	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
+	/* install the tty_port */
+	err = tty_port_install(&dev->port, driver, tty);
+	if (err)
+		rfcomm_tty_cleanup(tty);
 
-		if (dlc->state == BT_CLOSED) {
-			err = -dev->err;
-			break;
-		}
+	return err;
+}
 
-		if (dlc->state == BT_CONNECTED)
-			break;
+static int rfcomm_tty_open(struct tty_struct *tty, struct file *filp)
+{
+	struct rfcomm_dev *dev = tty->driver_data;
+	int err;
 
-		if (signal_pending(current)) {
-			err = -EINTR;
-			break;
-		}
+	BT_DBG("tty %p id %d", tty, tty->index);
 
-		tty_unlock(tty);
-		schedule();
-		tty_lock(tty);
-	}
-	set_current_state(TASK_RUNNING);
-	remove_wait_queue(&dev->wait, &wait);
+	BT_DBG("dev %p dst %pMR channel %d opened %d", dev, &dev->dst,
+	       dev->channel, dev->port.count);
 
-	if (err == 0)
-		device_move(dev->tty_dev, rfcomm_get_device(dev),
-			    DPM_ORDER_DEV_AFTER_PARENT);
+	err = tty_port_open(&dev->port, tty, filp);
+	if (err)
+		return err;
 
+	/*
+	 * FIXME: rfcomm should use proper flow control for
+	 * received data. This hack will be unnecessary and can
+	 * be removed when that's implemented
+	 */
 	rfcomm_tty_copy_pending(dev);
 
 	rfcomm_dlc_unthrottle(dev->dlc);
 
-	return err;
+	return 0;
 }
 
 static void rfcomm_tty_close(struct tty_struct *tty, struct file *filp)
 {
 	struct rfcomm_dev *dev = (struct rfcomm_dev *) tty->driver_data;
-	unsigned long flags;
-
-	if (!dev)
-		return;
 
 	BT_DBG("tty %p dev %p dlc %p opened %d", tty, dev, dev->dlc,
 						dev->port.count);
 
-	spin_lock_irqsave(&dev->port.lock, flags);
-	if (!--dev->port.count) {
-		spin_unlock_irqrestore(&dev->port.lock, flags);
-		if (dev->tty_dev->parent)
-			device_move(dev->tty_dev, NULL, DPM_ORDER_DEV_LAST);
-
-		/* Close DLC and dettach TTY */
-		rfcomm_dlc_close(dev->dlc, 0);
-
-		clear_bit(RFCOMM_TTY_ATTACHED, &dev->flags);
-
-		rfcomm_dlc_lock(dev->dlc);
-		tty->driver_data = NULL;
-		dev->port.tty = NULL;
-		rfcomm_dlc_unlock(dev->dlc);
-
-		if (test_bit(RFCOMM_TTY_RELEASED, &dev->flags)) {
-			spin_lock(&rfcomm_dev_lock);
-			list_del_init(&dev->list);
-			spin_unlock(&rfcomm_dev_lock);
-
-			tty_port_put(&dev->port);
-		}
-	} else
-		spin_unlock_irqrestore(&dev->port.lock, flags);
-
-	tty_port_put(&dev->port);
+	tty_port_close(&dev->port, tty, filp);
 }
 
 static int rfcomm_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
@@ -1055,17 +1040,11 @@ static void rfcomm_tty_hangup(struct tty_struct *tty)
 
 	BT_DBG("tty %p dev %p", tty, dev);
 
-	if (!dev)
-		return;
-
-	rfcomm_tty_flush_buffer(tty);
+	tty_port_hangup(&dev->port);
 
-	if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
-		if (rfcomm_dev_get(dev->id) == NULL)
-			return;
-		rfcomm_dev_del(dev);
+	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)
@@ -1128,6 +1107,8 @@ static const struct tty_operations rfcomm_ops = {
 	.wait_until_sent	= rfcomm_tty_wait_until_sent,
 	.tiocmget		= rfcomm_tty_tiocmget,
 	.tiocmset		= rfcomm_tty_tiocmset,
+	.install                = rfcomm_tty_install,
+	.cleanup                = rfcomm_tty_cleanup,
 };
 
 int __init rfcomm_init_ttys(void)
@@ -1146,7 +1127,7 @@ int __init rfcomm_init_ttys(void)
 	rfcomm_tty_driver->subtype	= SERIAL_TYPE_NORMAL;
 	rfcomm_tty_driver->flags	= TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
 	rfcomm_tty_driver->init_termios	= tty_std_termios;
-	rfcomm_tty_driver->init_termios.c_cflag	= B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+	rfcomm_tty_driver->init_termios.c_cflag	= B9600 | CS8 | CREAD | HUPCL;
 	rfcomm_tty_driver->init_termios.c_lflag &= ~ICANON;
 	tty_set_operations(rfcomm_tty_driver, &rfcomm_ops);