Merge tag 'tty-3.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull TTY updates from Greg Kroah-Hartman:
 "Here's the big TTY/serial driver pull request for the 3.5-rc1 merge
  window.

  Nothing major in here, just lots of incremental changes from Alan and
  Jiri reworking some tty core things to behave better and to get a more
  solid grasp on some of the nasty tty locking issues.

  There are a few tty and serial driver updates in here as well.

  All of this has been in the linux-next releases for a while with no
  problems.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'tty-3.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (115 commits)
  serial: bfin_uart: Make MMR access compatible with 32 bits bf609 style controller.
  serial: bfin_uart: RTS and CTS MMRs can be either 16-bit width or 32-bit width.
  serial: bfin_uart: narrow the reboot condition in DMA tx interrupt
  serial: bfin_uart: Adapt bf5xx serial driver to bf60x serial4 controller.
  Revert "serial_core: Update buffer overrun statistics."
  tty: hvc_xen: NULL dereference on allocation failure
  tty: Fix LED error return
  tty: Allow uart_register/unregister/register
  tty: move global ldisc idle waitqueue to the individual ldisc
  serial8250-em: Add DT support
  serial8250-em: clk_get() IS_ERR() error handling fix
  serial_core: Update buffer overrun statistics.
  tty: drop the pty lock during hangup
  cris: fix missing tty arg in wait_event_interruptible_tty call
  tty/amiserial: Add missing argument for tty_unlock()
  tty_lock: Localise the lock
  pty: Lock the devpts bits privately
  tty_lock: undo the old tty_lock use on the ctty
  serial8250-em: Emma Mobile UART driver V2
  Add missing call to uart_update_timeout()
  ...

41 files changed, 1316 insertions, 1217 deletions

diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 6cc4358f68c..35819e31262 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1033,7 +1033,7 @@ static int get_serial_info(struct tty_struct *tty, struct serial_state *state,
 	if (!retinfo)
 		return -EFAULT;
 	memset(&tmp, 0, sizeof(tmp));
-	tty_lock();
+	tty_lock(tty);
 	tmp.line = tty->index;
 	tmp.port = state->port;
 	tmp.flags = state->tport.flags;
@@ -1042,7 +1042,7 @@ static int get_serial_info(struct tty_struct *tty, struct serial_state *state,
 	tmp.close_delay = state->tport.close_delay;
 	tmp.closing_wait = state->tport.closing_wait;
 	tmp.custom_divisor = state->custom_divisor;
-	tty_unlock();
+	tty_unlock(tty);
 	if (copy_to_user(retinfo,&tmp,sizeof(*retinfo)))
 		return -EFAULT;
 	return 0;
@@ -1059,12 +1059,12 @@ static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
 	if (copy_from_user(&new_serial,new_info,sizeof(new_serial)))
 		return -EFAULT;
 
-	tty_lock();
+	tty_lock(tty);
 	change_spd = ((new_serial.flags ^ port->flags) & ASYNC_SPD_MASK) ||
 		new_serial.custom_divisor != state->custom_divisor;
 	if (new_serial.irq || new_serial.port != state->port ||
 			new_serial.xmit_fifo_size != state->xmit_fifo_size) {
-		tty_unlock();
+		tty_unlock(tty);
 		return -EINVAL;
 	}
   
@@ -1074,7 +1074,7 @@ static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
 		    (new_serial.xmit_fifo_size != state->xmit_fifo_size) ||
 		    ((new_serial.flags & ~ASYNC_USR_MASK) !=
 		     (port->flags & ~ASYNC_USR_MASK))) {
-			tty_unlock();
+			tty_unlock(tty);
 			return -EPERM;
 		}
 		port->flags = ((port->flags & ~ASYNC_USR_MASK) |
@@ -1084,7 +1084,7 @@ static int set_serial_info(struct tty_struct *tty, struct serial_state *state,
 	}
 
 	if (new_serial.baud_base < 9600) {
-		tty_unlock();
+		tty_unlock(tty);
 		return -EINVAL;
 	}
 
@@ -1116,7 +1116,7 @@ check_and_exit:
 		}
 	} else
 		retval = startup(tty, state);
-	tty_unlock();
+	tty_unlock(tty);
 	return retval;
 }
 
diff --git a/drivers/tty/bfin_jtag_comm.c b/drivers/tty/bfin_jtag_comm.c
index 946f799861f..61fc74fe174 100644
--- a/drivers/tty/bfin_jtag_comm.c
+++ b/drivers/tty/bfin_jtag_comm.c
@@ -62,9 +62,7 @@ static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d)
 
 static struct tty_driver *bfin_jc_driver;
 static struct task_struct *bfin_jc_kthread;
-static struct tty_struct * volatile bfin_jc_tty;
-static unsigned long bfin_jc_count;
-static DEFINE_MUTEX(bfin_jc_tty_mutex);
+static struct tty_port port;
 static volatile struct circ_buf bfin_jc_write_buf;
 
 static int
@@ -73,18 +71,21 @@ bfin_jc_emudat_manager(void *arg)
 	uint32_t inbound_len = 0, outbound_len = 0;
 
 	while (!kthread_should_stop()) {
+		struct tty_struct *tty = tty_port_tty_get(&port);
 		/* no one left to give data to, so sleep */
-		if (bfin_jc_tty == NULL && circ_empty(&bfin_jc_write_buf)) {
+		if (tty == NULL && circ_empty(&bfin_jc_write_buf)) {
 			pr_debug("waiting for readers\n");
 			__set_current_state(TASK_UNINTERRUPTIBLE);
 			schedule();
 			__set_current_state(TASK_RUNNING);
+			continue;
 		}
 
 		/* no data available, so just chill */
 		if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) {
 			pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n",
 				inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head);
+			tty_kref_put(tty);
 			if (inbound_len)
 				schedule();
 			else
@@ -94,9 +95,6 @@ bfin_jc_emudat_manager(void *arg)
 
 		/* if incoming data is ready, eat it */
 		if (bfin_read_DBGSTAT() & EMUDIF) {
-			struct tty_struct *tty;
-			mutex_lock(&bfin_jc_tty_mutex);
-			tty = (struct tty_struct *)bfin_jc_tty;
 			if (tty != NULL) {
 				uint32_t emudat = bfin_read_emudat();
 				if (inbound_len == 0) {
@@ -110,7 +108,6 @@ bfin_jc_emudat_manager(void *arg)
 					tty_flip_buffer_push(tty);
 				}
 			}
-			mutex_unlock(&bfin_jc_tty_mutex);
 		}
 
 		/* if outgoing data is ready, post it */
@@ -120,7 +117,6 @@ bfin_jc_emudat_manager(void *arg)
 				bfin_write_emudat(outbound_len);
 				pr_debug("outgoing length: 0x%08x\n", outbound_len);
 			} else {
-				struct tty_struct *tty;
 				int tail = bfin_jc_write_buf.tail;
 				size_t ate = (4 <= outbound_len ? 4 : outbound_len);
 				uint32_t emudat =
@@ -132,14 +128,12 @@ bfin_jc_emudat_manager(void *arg)
 				);
 				bfin_jc_write_buf.tail += ate;
 				outbound_len -= ate;
-				mutex_lock(&bfin_jc_tty_mutex);
-				tty = (struct tty_struct *)bfin_jc_tty;
 				if (tty)
 					tty_wakeup(tty);
-				mutex_unlock(&bfin_jc_tty_mutex);
 				pr_debug("  outgoing data: 0x%08x (pushing %zu)\n", emudat, ate);
 			}
 		}
+		tty_kref_put(tty);
 	}
 
 	__set_current_state(TASK_RUNNING);
@@ -149,24 +143,28 @@ bfin_jc_emudat_manager(void *arg)
 static int
 bfin_jc_open(struct tty_struct *tty, struct file *filp)
 {
-	mutex_lock(&bfin_jc_tty_mutex);
-	pr_debug("open %lu\n", bfin_jc_count);
-	++bfin_jc_count;
-	bfin_jc_tty = tty;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port.lock, flags);
+	port.count++;
+	spin_unlock_irqrestore(&port.lock, flags);
+	tty_port_tty_set(&port, tty);
 	wake_up_process(bfin_jc_kthread);
-	mutex_unlock(&bfin_jc_tty_mutex);
 	return 0;
 }
 
 static void
 bfin_jc_close(struct tty_struct *tty, struct file *filp)
 {
-	mutex_lock(&bfin_jc_tty_mutex);
-	pr_debug("close %lu\n", bfin_jc_count);
-	if (--bfin_jc_count == 0)
-		bfin_jc_tty = NULL;
+	unsigned long flags;
+	bool last;
+
+	spin_lock_irqsave(&port.lock, flags);
+	last = --port.count == 0;
+	spin_unlock_irqrestore(&port.lock, flags);
+	if (last)
+		tty_port_tty_set(&port, NULL);
 	wake_up_process(bfin_jc_kthread);
-	mutex_unlock(&bfin_jc_tty_mutex);
 }
 
 /* XXX: we dont handle the put_char() case where we must handle count = 1 */
@@ -242,6 +240,8 @@ static int __init bfin_jc_init(void)
 {
 	int ret;
 
+	tty_port_init(&port);
+
 	bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME);
 	if (IS_ERR(bfin_jc_kthread))
 		return PTR_ERR(bfin_jc_kthread);
diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index e61cabdd69d..6984e1a2686 100644
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -1599,7 +1599,7 @@ static int cy_open(struct tty_struct *tty, struct file *filp)
 	 * If the port is the middle of closing, bail out now
 	 */
 	if (tty_hung_up_p(filp) || (info->port.flags & ASYNC_CLOSING)) {
-		wait_event_interruptible_tty(info->port.close_wait,
+		wait_event_interruptible_tty(tty, info->port.close_wait,
 				!(info->port.flags & ASYNC_CLOSING));
 		return (info->port.flags & ASYNC_HUP_NOTIFY) ? -EAGAIN: -ERESTARTSYS;
 	}
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index 8880adf5fc6..2d691eb7c40 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -107,7 +107,7 @@ static struct hvc_struct *hvc_get_by_index(int index)
 	list_for_each_entry(hp, &hvc_structs, next) {
 		spin_lock_irqsave(&hp->lock, flags);
 		if (hp->index == index) {
-			kref_get(&hp->kref);
+			tty_port_get(&hp->port);
 			spin_unlock_irqrestore(&hp->lock, flags);
 			spin_unlock(&hvc_structs_lock);
 			return hp;
@@ -229,9 +229,9 @@ static int __init hvc_console_init(void)
 console_initcall(hvc_console_init);
 
 /* callback when the kboject ref count reaches zero. */
-static void destroy_hvc_struct(struct kref *kref)
+static void hvc_port_destruct(struct tty_port *port)
 {
-	struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref);
+	struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
 	unsigned long flags;
 
 	spin_lock(&hvc_structs_lock);
@@ -264,7 +264,7 @@ int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
 	/* make sure no no tty has been registered in this index */
 	hp = hvc_get_by_index(index);
 	if (hp) {
-		kref_put(&hp->kref, destroy_hvc_struct);
+		tty_port_put(&hp->port);
 		return -1;
 	}
 
@@ -313,20 +313,17 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
 	if (!(hp = hvc_get_by_index(tty->index)))
 		return -ENODEV;
 
-	spin_lock_irqsave(&hp->lock, flags);
+	spin_lock_irqsave(&hp->port.lock, flags);
 	/* Check and then increment for fast path open. */
-	if (hp->count++ > 0) {
-		tty_kref_get(tty);
-		spin_unlock_irqrestore(&hp->lock, flags);
+	if (hp->port.count++ > 0) {
+		spin_unlock_irqrestore(&hp->port.lock, flags);
 		hvc_kick();
 		return 0;
 	} /* else count == 0 */
+	spin_unlock_irqrestore(&hp->port.lock, flags);
 
 	tty->driver_data = hp;
-
-	hp->tty = tty_kref_get(tty);
-
-	spin_unlock_irqrestore(&hp->lock, flags);
+	tty_port_tty_set(&hp->port, tty);
 
 	if (hp->ops->notifier_add)
 		rc = hp->ops->notifier_add(hp, hp->data);
@@ -338,12 +335,9 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
 	 * tty fields and return the kref reference.
 	 */
 	if (rc) {
-		spin_lock_irqsave(&hp->lock, flags);
-		hp->tty = NULL;
-		spin_unlock_irqrestore(&hp->lock, flags);
-		tty_kref_put(tty);
+		tty_port_tty_set(&hp->port, NULL);
 		tty->driver_data = NULL;
-		kref_put(&hp->kref, destroy_hvc_struct);
+		tty_port_put(&hp->port);
 		printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
 	}
 	/* Force wakeup of the polling thread */
@@ -370,12 +364,12 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
 
 	hp = tty->driver_data;
 
-	spin_lock_irqsave(&hp->lock, flags);
+	spin_lock_irqsave(&hp->port.lock, flags);
 
-	if (--hp->count == 0) {
+	if (--hp->port.count == 0) {
+		spin_unlock_irqrestore(&hp->port.lock, flags);
 		/* We are done with the tty pointer now. */
-		hp->tty = NULL;
-		spin_unlock_irqrestore(&hp->lock, flags);
+		tty_port_tty_set(&hp->port, NULL);
 
 		if (hp->ops->notifier_del)
 			hp->ops->notifier_del(hp, hp->data);
@@ -390,14 +384,13 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
 		 */
 		tty_wait_until_sent_from_close(tty, HVC_CLOSE_WAIT);
 	} else {
-		if (hp->count < 0)
+		if (hp->port.count < 0)
 			printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
-				hp->vtermno, hp->count);
-		spin_unlock_irqrestore(&hp->lock, flags);
+				hp->vtermno, hp->port.count);
+		spin_unlock_irqrestore(&hp->port.lock, flags);
 	}
 
-	tty_kref_put(tty);
-	kref_put(&hp->kref, destroy_hvc_struct);
+	tty_port_put(&hp->port);
 }
 
 static void hvc_hangup(struct tty_struct *tty)
@@ -412,32 +405,31 @@ static void hvc_hangup(struct tty_struct *tty)
 	/* cancel pending tty resize work */
 	cancel_work_sync(&hp->tty_resize);
 
-	spin_lock_irqsave(&hp->lock, flags);
+	spin_lock_irqsave(&hp->port.lock, flags);
 
 	/*
 	 * The N_TTY line discipline has problems such that in a close vs
 	 * open->hangup case this can be called after the final close so prevent
 	 * that from happening for now.
 	 */
-	if (hp->count <= 0) {
-		spin_unlock_irqrestore(&hp->lock, flags);
+	if (hp->port.count <= 0) {
+		spin_unlock_irqrestore(&hp->port.lock, flags);
 		return;
 	}
 
-	temp_open_count = hp->count;
-	hp->count = 0;
-	hp->n_outbuf = 0;
-	hp->tty = NULL;
+	temp_open_count = hp->port.count;
+	hp->port.count = 0;
+	spin_unlock_irqrestore(&hp->port.lock, flags);
+	tty_port_tty_set(&hp->port, NULL);
 
-	spin_unlock_irqrestore(&hp->lock, flags);
+	hp->n_outbuf = 0;
 
 	if (hp->ops->notifier_hangup)
 		hp->ops->notifier_hangup(hp, hp->data);
 
 	while(temp_open_count) {
 		--temp_open_count;
-		tty_kref_put(tty);
-		kref_put(&hp->kref, destroy_hvc_struct);
+		tty_port_put(&hp->port);
 	}
 }
 
@@ -478,7 +470,8 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
 	if (!hp)
 		return -EPIPE;
 
-	if (hp->count <= 0)
+	/* FIXME what's this (unprotected) check for? */
+	if (hp->port.count <= 0)
 		return -EIO;
 
 	spin_lock_irqsave(&hp->lock, flags);
@@ -526,13 +519,12 @@ static void hvc_set_winsz(struct work_struct *work)
 
 	hp = container_of(work, struct hvc_struct, tty_resize);
 
-	spin_lock_irqsave(&hp->lock, hvc_flags);
-	if (!hp->tty) {
-		spin_unlock_irqrestore(&hp->lock, hvc_flags);
+	tty = tty_port_tty_get(&hp->port);
+	if (!tty)
 		return;
-	}
-	ws  = hp->ws;
-	tty = tty_kref_get(hp->tty);
+
+	spin_lock_irqsave(&hp->lock, hvc_flags);
+	ws = hp->ws;
 	spin_unlock_irqrestore(&hp->lock, hvc_flags);
 
 	tty_do_resize(tty, &ws);
@@ -601,7 +593,7 @@ int hvc_poll(struct hvc_struct *hp)
 	}
 
 	/* No tty attached, just skip */
-	tty = tty_kref_get(hp->tty);
+	tty = tty_port_tty_get(&hp->port);
 	if (tty == NULL)
 		goto bail;
 
@@ -681,8 +673,7 @@ int hvc_poll(struct hvc_struct *hp)
 
 		tty_flip_buffer_push(tty);
 	}
-	if (tty)
-		tty_kref_put(tty);
+	tty_kref_put(tty);
 
 	return poll_mask;
 }
@@ -817,6 +808,10 @@ static const struct tty_operations hvc_ops = {
 #endif
 };
 
+static const struct tty_port_operations hvc_port_ops = {
+	.destruct = hvc_port_destruct,
+};
+
 struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
 			     const struct hv_ops *ops,
 			     int outbuf_size)
@@ -842,7 +837,8 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
 	hp->outbuf_size = outbuf_size;
 	hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
 
-	kref_init(&hp->kref);
+	tty_port_init(&hp->port);
+	hp->port.ops = &hvc_port_ops;
 
 	INIT_WORK(&hp->tty_resize, hvc_set_winsz);
 	spin_lock_init(&hp->lock);
@@ -875,9 +871,9 @@ int hvc_remove(struct hvc_struct *hp)
 	unsigned long flags;
 	struct tty_struct *tty;
 
-	spin_lock_irqsave(&hp->lock, flags);
-	tty = tty_kref_get(hp->tty);
+	tty = tty_port_tty_get(&hp->port);
 
+	spin_lock_irqsave(&hp->lock, flags);
 	if (hp->index < MAX_NR_HVC_CONSOLES)
 		vtermnos[hp->index] = -1;
 
@@ -891,7 +887,7 @@ int hvc_remove(struct hvc_struct *hp)
 	 * kref cause it to be removed, which will probably be the tty_vhangup
 	 * below.
 	 */
-	kref_put(&hp->kref, destroy_hvc_struct);
+	tty_port_put(&hp->port);
 
 	/*
 	 * This function call will auto chain call hvc_hangup.
diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h
index c335a1492a5..674d23cb919 100644
--- a/drivers/tty/hvc/hvc_console.h
+++ b/drivers/tty/hvc/hvc_console.h
@@ -46,10 +46,9 @@
 #define HVC_ALLOC_TTY_ADAPTERS	8
 
 struct hvc_struct {
+	struct tty_port port;
 	spinlock_t lock;
 	int index;
-	struct tty_struct *tty;
-	int count;
 	int do_wakeup;
 	char *outbuf;
 	int outbuf_size;
@@ -61,7 +60,6 @@ struct hvc_struct {
 	struct winsize ws;
 	struct work_struct tty_resize;
 	struct list_head next;
-	struct kref kref; /* ref count & hvc_struct lifetime */
 };
 
 /* implemented by a low level driver */
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 83d5c88e716..d3d91dae065 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -430,9 +430,9 @@ static int __devinit xencons_probe(struct xenbus_device *dev,
 	if (devid == 0)
 		return -ENODEV;
 
-	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL | __GFP_ZERO);
+	info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
 	if (!info)
-		goto error_nomem;
+		return -ENOMEM;
 	dev_set_drvdata(&dev->dev, info);
 	info->xbdev = dev;
 	info->vtermno = xenbus_devid_to_vtermno(devid);
diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c
index 3436436fe2d..d56788c8397 100644
--- a/drivers/tty/hvc/hvcs.c
+++ b/drivers/tty/hvc/hvcs.c
@@ -261,6 +261,7 @@ static DEFINE_SPINLOCK(hvcs_pi_lock);
 
 /* One vty-server per hvcs_struct */
 struct hvcs_struct {
+	struct tty_port port;
 	spinlock_t lock;
 
 	/*
@@ -269,9 +270,6 @@ struct hvcs_struct {
 	 */
 	unsigned int index;
 
-	struct tty_struct *tty;
-	int open_count;
-
 	/*
 	 * Used to tell the driver kernel_thread what operations need to take
 	 * place upon this hvcs_struct instance.
@@ -290,12 +288,11 @@ struct hvcs_struct {
 	int chars_in_buffer;
 
 	/*
-	 * Any variable below the kref is valid before a tty is connected and
+	 * Any variable below is valid before a tty is connected and
 	 * stays valid after the tty is disconnected.  These shouldn't be
 	 * whacked until the kobject refcount reaches zero though some entries
 	 * may be changed via sysfs initiatives.
 	 */
-	struct kref kref; /* ref count & hvcs_struct lifetime */
 	int connected; /* is the vty-server currently connected to a vty? */
 	uint32_t p_unit_address; /* partner unit address */
 	uint32_t p_partition_ID; /* partner partition ID */
@@ -304,9 +301,6 @@ struct hvcs_struct {
 	struct vio_dev *vdev;
 };
 
-/* Required to back map a kref to its containing object */
-#define from_kref(k) container_of(k, struct hvcs_struct, kref)
-
 static LIST_HEAD(hvcs_structs);
 static DEFINE_SPINLOCK(hvcs_structs_lock);
 static DEFINE_MUTEX(hvcs_init_mutex);
@@ -422,7 +416,7 @@ static ssize_t hvcs_vterm_state_store(struct device *dev, struct device_attribut
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
 
-	if (hvcsd->open_count > 0) {
+	if (hvcsd->port.count > 0) {
 		spin_unlock_irqrestore(&hvcsd->lock, flags);
 		printk(KERN_INFO "HVCS: vterm state unchanged.  "
 				"The hvcs device node is still in use.\n");
@@ -564,7 +558,7 @@ static irqreturn_t hvcs_handle_interrupt(int irq, void *dev_instance)
 static void hvcs_try_write(struct hvcs_struct *hvcsd)
 {
 	uint32_t unit_address = hvcsd->vdev->unit_address;
-	struct tty_struct *tty = hvcsd->tty;
+	struct tty_struct *tty = hvcsd->port.tty;
 	int sent;
 
 	if (hvcsd->todo_mask & HVCS_TRY_WRITE) {
@@ -602,7 +596,7 @@ static int hvcs_io(struct hvcs_struct *hvcsd)
 	spin_lock_irqsave(&hvcsd->lock, flags);
 
 	unit_address = hvcsd->vdev->unit_address;
-	tty = hvcsd->tty;
+	tty = hvcsd->port.tty;
 
 	hvcs_try_write(hvcsd);
 
@@ -701,10 +695,9 @@ static void hvcs_return_index(int index)
 		hvcs_index_list[index] = -1;
 }
 
-/* callback when the kref ref count reaches zero */
-static void destroy_hvcs_struct(struct kref *kref)
+static void hvcs_destruct_port(struct tty_port *p)
 {
-	struct hvcs_struct *hvcsd = from_kref(kref);
+	struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port);
 	struct vio_dev *vdev;
 	unsigned long flags;
 
@@ -741,6 +734,10 @@ static void destroy_hvcs_struct(struct kref *kref)
 	kfree(hvcsd);
 }
 
+static const struct tty_port_operations hvcs_port_ops = {
+	.destruct = hvcs_destruct_port,
+};
+
 static int hvcs_get_index(void)
 {
 	int i;
@@ -789,10 +786,9 @@ static int __devinit hvcs_probe(
 	if (!hvcsd)
 		return -ENODEV;
 
-
+	tty_port_init(&hvcsd->port);
+	hvcsd->port.ops = &hvcs_port_ops;
 	spin_lock_init(&hvcsd->lock);
-	/* Automatically incs the refcount the first time */
-	kref_init(&hvcsd->kref);
 
 	hvcsd->vdev = dev;
 	dev_set_drvdata(&dev->dev, hvcsd);
@@ -852,7 +848,7 @@ static int __devexit hvcs_remove(struct vio_dev *dev)
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
 
-	tty = hvcsd->tty;
+	tty = hvcsd->port.tty;
 
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
 
@@ -860,7 +856,7 @@ static int __devexit hvcs_remove(struct vio_dev *dev)
 	 * Let the last holder of this object cause it to be removed, which
 	 * would probably be tty_hangup below.
 	 */
-	kref_put(&hvcsd->kref, destroy_hvcs_struct);
+	tty_port_put(&hvcsd->port);
 
 	/*
 	 * The hangup is a scheduled function which will auto chain call
@@ -1094,7 +1090,7 @@ static struct hvcs_struct *hvcs_get_by_index(int index)
 	list_for_each_entry(hvcsd, &hvcs_structs, next) {
 		spin_lock_irqsave(&hvcsd->lock, flags);
 		if (hvcsd->index == index) {
-			kref_get(&hvcsd->kref);
+			tty_port_get(&hvcsd->port);
 			spin_unlock_irqrestore(&hvcsd->lock, flags);
 			spin_unlock(&hvcs_structs_lock);
 			return hvcsd;
@@ -1138,8 +1134,8 @@ static int hvcs_open(struct tty_struct *tty, struct file *filp)
 		if ((retval = hvcs_partner_connect(hvcsd)))
 			goto error_release;
 
-	hvcsd->open_count = 1;
-	hvcsd->tty = tty;
+	hvcsd->port.count = 1;
+	hvcsd->port.tty = tty;
 	tty->driver_data = hvcsd;
 
 	memset(&hvcsd->buffer[0], 0x00, HVCS_BUFF_LEN);
@@ -1160,7 +1156,7 @@ static int hvcs_open(struct tty_struct *tty, struct file *filp)
 	 * and will grab the spinlock and free the connection if it fails.
 	 */
 	if (((rc = hvcs_enable_device(hvcsd, unit_address, irq, vdev)))) {
-		kref_put(&hvcsd->kref, destroy_hvcs_struct);
+		tty_port_put(&hvcsd->port);
 		printk(KERN_WARNING "HVCS: enable device failed.\n");
 		return rc;
 	}
@@ -1171,8 +1167,8 @@ fast_open:
 	hvcsd = tty->driver_data;
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
-	kref_get(&hvcsd->kref);
-	hvcsd->open_count++;
+	tty_port_get(&hvcsd->port);
+	hvcsd->port.count++;
 	hvcsd->todo_mask |= HVCS_SCHED_READ;
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
 
@@ -1186,7 +1182,7 @@ open_success:
 
 error_release:
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
-	kref_put(&hvcsd->kref, destroy_hvcs_struct);
+	tty_port_put(&hvcsd->port);
 
 	printk(KERN_WARNING "HVCS: partner connect failed.\n");
 	return retval;
@@ -1216,7 +1212,7 @@ static void hvcs_close(struct tty_struct *tty, struct file *filp)
 	hvcsd = tty->driver_data;
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
-	if (--hvcsd->open_count == 0) {
+	if (--hvcsd->port.count == 0) {
 
 		vio_disable_interrupts(hvcsd->vdev);
 
@@ -1225,7 +1221,7 @@ static void hvcs_close(struct tty_struct *tty, struct file *filp)
 		 * execute any operations on the TTY even though it is obligated
 		 * to deliver any pending I/O to the hypervisor.
 		 */
-		hvcsd->tty = NULL;
+		hvcsd->port.tty = NULL;
 
 		irq = hvcsd->vdev->irq;
 		spin_unlock_irqrestore(&hvcsd->lock, flags);
@@ -1240,16 +1236,16 @@ static void hvcs_close(struct tty_struct *tty, struct file *filp)
 		tty->driver_data = NULL;
 
 		free_irq(irq, hvcsd);
-		kref_put(&hvcsd->kref, destroy_hvcs_struct);
+		tty_port_put(&hvcsd->port);
 		return;
-	} else if (hvcsd->open_count < 0) {
+	} else if (hvcsd->port.count < 0) {
 		printk(KERN_ERR "HVCS: vty-server@%X open_count: %d"
 				" is missmanaged.\n",
-		hvcsd->vdev->unit_address, hvcsd->open_count);
+		hvcsd->vdev->unit_address, hvcsd->port.count);
 	}
 
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
-	kref_put(&hvcsd->kref, destroy_hvcs_struct);
+	tty_port_put(&hvcsd->port);
 }
 
 static void hvcs_hangup(struct tty_struct * tty)
@@ -1261,7 +1257,7 @@ static void hvcs_hangup(struct tty_