tty: usb-serial krefs

Use kref in the USB serial drivers so that we don't free tty structures
from under the URB receive handlers as has historically been the case if
you were unlucky. This also gives us a framework for general tty drivers to
use tty_port objects and refcount.

Contains two err->dev_err changes merged together to fix clashes in the
-next tree.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

35 files changed, 269 insertions, 208 deletions

diff --git a/drivers/usb/serial/aircable.c b/drivers/usb/serial/aircable.c
index 79ea98c66fa8..99fb7dc59c45 100644
--- a/drivers/usb/serial/aircable.c
+++ b/drivers/usb/serial/aircable.c
@@ -272,7 +272,7 @@ static void aircable_read(struct work_struct *work)
 	 * 64 bytes, to ensure I do not get throttled.
 	 * Ask USB mailing list for better aproach.
 	 */
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 
 	if (!tty) {
 		schedule_work(&priv->rx_work);
@@ -283,12 +283,13 @@ static void aircable_read(struct work_struct *work)
 	count = min(64, serial_buf_data_avail(priv->rx_buf));
 
 	if (count <= 0)
-		return; /* We have finished sending everything. */
+		goto out; /* We have finished sending everything. */
 
 	tty_prepare_flip_string(tty, &data, count);
 	if (!data) {
-		err("%s- kzalloc(%d) failed.", __func__, count);
-		return;
+		dev_err(&port->dev, "%s- kzalloc(%d) failed.",
+							__func__, count);
+		goto out;
 	}
 
 	serial_buf_get(priv->rx_buf, data, count);
@@ -297,7 +298,8 @@ static void aircable_read(struct work_struct *work)
 
 	if (serial_buf_data_avail(priv->rx_buf))
 		schedule_work(&priv->rx_work);
-
+out:		
+	tty_kref_put(tty);
 	return;
 }
 /* End of private methods */
@@ -495,7 +497,7 @@ static void aircable_read_bulk_callback(struct urb *urb)
 	usb_serial_debug_data(debug, &port->dev, __func__,
 				urb->actual_length, urb->transfer_buffer);
 
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (tty && urb->actual_length) {
 		if (urb->actual_length <= 2) {
 			/* This is an incomplete package */
@@ -527,6 +529,7 @@ static void aircable_read_bulk_callback(struct urb *urb)
 		}
 		aircable_read(&priv->rx_work);
 	}
+	tty_kref_put(tty);
 
 	/* Schedule the next read _if_ we are still open */
 	if (port->port.count) {
diff --git a/drivers/usb/serial/belkin_sa.c b/drivers/usb/serial/belkin_sa.c
index 2ebe06c3405a..1913bc7c5f0b 100644
--- a/drivers/usb/serial/belkin_sa.c
+++ b/drivers/usb/serial/belkin_sa.c
@@ -322,7 +322,7 @@ static void belkin_sa_read_int_callback(struct urb *urb)
 	 * to look in to this before committing any code.
 	 */
 	if (priv->last_lsr & BELKIN_SA_LSR_ERR) {
-		tty = port->port.tty;
+		tty = tty_port_tty_get(&port->port);
 		/* Overrun Error */
 		if (priv->last_lsr & BELKIN_SA_LSR_OE) {
 		}
@@ -335,6 +335,7 @@ static void belkin_sa_read_int_callback(struct urb *urb)
 		/* Break Indicator */
 		if (priv->last_lsr & BELKIN_SA_LSR_BI) {
 		}
+		tty_kref_put(tty);
 	}
 #endif
 	spin_unlock_irqrestore(&priv->lock, flags);
diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
index e980766bb84b..5b20de130e08 100644
--- a/drivers/usb/serial/console.c
+++ b/drivers/usb/serial/console.c
@@ -117,7 +117,7 @@ static int usb_console_setup(struct console *co, char *options)
 	}
 
 	port = serial->port[0];
-	port->port.tty = NULL;
+	tty_port_tty_set(&port->port, NULL);
 
 	info->port = port;
 
@@ -143,7 +143,7 @@ static int usb_console_setup(struct console *co, char *options)
 			}
 			memset(&dummy, 0, sizeof(struct ktermios));
 			tty->termios = termios;
-			port->port.tty = tty;
+			tty_port_tty_set(&port->port, tty);
 		}
 
 		/* only call the device specific open if this
@@ -163,7 +163,7 @@ static int usb_console_setup(struct console *co, char *options)
 			tty_termios_encode_baud_rate(termios, baud, baud);
 			serial->type->set_termios(tty, port, &dummy);
 
-			port->port.tty = NULL;
+			tty_port_tty_set(&port->port, NULL);
 			kfree(termios);
 			kfree(tty);
 		}
@@ -176,7 +176,7 @@ out:
 	return retval;
 free_termios:
 	kfree(termios);
-	port->port.tty = NULL;
+	tty_port_tty_set(&port->port, NULL);
 free_tty:
 	kfree(tty);
 reset_open_count:
diff --git a/drivers/usb/serial/cyberjack.c b/drivers/usb/serial/cyberjack.c
index b4d72351cb96..94ef36c4764b 100644
--- a/drivers/usb/serial/cyberjack.c
+++ b/drivers/usb/serial/cyberjack.c
@@ -384,7 +384,7 @@ static void cyberjack_read_bulk_callback(struct urb *urb)
 		return;
 	}
 
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (!tty) {
 		dbg("%s - ignoring since device not open\n", __func__);
 		return;
@@ -394,6 +394,7 @@ static void cyberjack_read_bulk_callback(struct urb *urb)
 		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 	}
+	tty_kref_put(tty);
 
 	spin_lock(&priv->lock);
 
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 22837a3f2f89..f3514a91f915 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -1286,7 +1286,7 @@ static void cypress_read_int_callback(struct urb *urb)
 	}
 	spin_unlock_irqrestore(&priv->lock, flags);
 
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (!tty) {
 		dbg("%s - bad tty pointer - exiting", __func__);
 		return;
@@ -1362,7 +1362,7 @@ static void cypress_read_int_callback(struct urb *urb)
 					data[i]);
 			tty_insert_flip_char(tty, data[i], tty_flag);
 		}
-		tty_flip_buffer_push(port->port.tty);
+		tty_flip_buffer_push(tty);
 	}
 
 	spin_lock_irqsave(&priv->lock, flags);
@@ -1371,6 +1371,7 @@ static void cypress_read_int_callback(struct urb *urb)
 	spin_unlock_irqrestore(&priv->lock, flags);
 
 continue_read:
+	tty_kref_put(tty);
 
 	/* Continue trying to always read... unless the port has closed. */
 
diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index 240aad1acaab..5756ac6d6c92 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -604,7 +604,9 @@ static void digi_wakeup_write_lock(struct work_struct *work)
 
 static void digi_wakeup_write(struct usb_serial_port *port)
 {
-	tty_wakeup(port->port.tty);
+	struct tty_struct *tty = tty_port_tty_get(&port->port);
+	tty_wakeup(tty);
+	tty_kref_put(tty);
 }
 
 
@@ -1668,7 +1670,7 @@ static int digi_read_inb_callback(struct urb *urb)
 {
 
 	struct usb_serial_port *port = urb->context;
-	struct tty_struct *tty = port->port.tty;
+	struct tty_struct *tty;
 	struct digi_port *priv = usb_get_serial_port_data(port);
 	int opcode = ((unsigned char *)urb->transfer_buffer)[0];
 	int len = ((unsigned char *)urb->transfer_buffer)[1];
@@ -1692,6 +1694,7 @@ static int digi_read_inb_callback(struct urb *urb)
 		return -1;
 	}
 
+	tty = tty_port_tty_get(&port->port);
 	spin_lock(&priv->dp_port_lock);
 
 	/* check for throttle; if set, do not resubmit read urb */
@@ -1735,6 +1738,7 @@ static int digi_read_inb_callback(struct urb *urb)
 		}
 	}
 	spin_unlock(&priv->dp_port_lock);
+	tty_kref_put(tty);
 
 	if (opcode == DIGI_CMD_RECEIVE_DISABLE)
 		dbg("%s: got RECEIVE_DISABLE", __func__);
@@ -1760,6 +1764,7 @@ static int digi_read_oob_callback(struct urb *urb)
 
 	struct usb_serial_port *port = urb->context;
 	struct usb_serial *serial = port->serial;
+	struct tty_struct *tty;
 	struct digi_port *priv = usb_get_serial_port_data(port);
 	int opcode, line, status, val;
 	int i;
@@ -1787,10 +1792,11 @@ static int digi_read_oob_callback(struct urb *urb)
 		if (priv == NULL)
 			return -1;
 
+		tty = tty_port_tty_get(&port->port);
 		rts = 0;
 		if (port->port.count)
-			rts = port->port.tty->termios->c_cflag & CRTSCTS;
-
+			rts = tty->termios->c_cflag & CRTSCTS;
+		
 		if (opcode == DIGI_CMD_READ_INPUT_SIGNALS) {
 			spin_lock(&priv->dp_port_lock);
 			/* convert from digi flags to termiox flags */
@@ -1798,14 +1804,14 @@ static int digi_read_oob_callback(struct urb *urb)
 				priv->dp_modem_signals |= TIOCM_CTS;
 				/* port must be open to use tty struct */
 				if (rts) {
-					port->port.tty->hw_stopped = 0;
+					tty->hw_stopped = 0;
 					digi_wakeup_write(port);
 				}
 			} else {
 				priv->dp_modem_signals &= ~TIOCM_CTS;
 				/* port must be open to use tty struct */
 				if (rts)
-					port->port.tty->hw_stopped = 1;
+					tty->hw_stopped = 1;
 			}
 			if (val & DIGI_READ_INPUT_SIGNALS_DSR)
 				priv->dp_modem_signals |= TIOCM_DSR;
@@ -1830,6 +1836,7 @@ static int digi_read_oob_callback(struct urb *urb)
 		} else if (opcode == DIGI_CMD_IFLUSH_FIFO) {
 			wake_up_interruptible(&priv->dp_flush_wait);
 		}
+		tty_kref_put(tty);
 	}
 	return 0;
 
diff --git a/drivers/usb/serial/empeg.c b/drivers/usb/serial/empeg.c
index a6ab5b58d9ca..1072e847280f 100644
--- a/drivers/usb/serial/empeg.c
+++ b/drivers/usb/serial/empeg.c
@@ -33,9 +33,8 @@
  *	Moved MOD_DEC_USE_COUNT to end of empeg_close().
  *
  * (12/03/2000) gb
- *	Added port->port.tty->ldisc.set_termios(port->port.tty, NULL) to
- *	empeg_open(). This notifies the tty driver that the termios have
- *	changed.
+ *	Added tty->ldisc.set_termios(port, tty, NULL) to empeg_open().
+ *	This notifies the tty driver that the termios have changed.
  *
  * (11/13/2000) gb
  *	Moved tty->low_latency = 1 from empeg_read_bulk_callback() to
@@ -354,7 +353,7 @@ static void empeg_read_bulk_callback(struct urb *urb)
 
 	usb_serial_debug_data(debug, &port->dev, __func__,
 						urb->actual_length, data);
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 
 	if (urb->actual_length) {
 		tty_buffer_request_room(tty, urb->actual_length);
@@ -362,6 +361,7 @@ static void empeg_read_bulk_callback(struct urb *urb)
 		tty_flip_buffer_push(tty);
 		bytes_in += urb->actual_length;
 	}
+	tty_kref_put(tty);
 
 	/* Continue trying to always read  */
 	usb_fill_bulk_urb(
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 1ac7e802b4b6..c2ac129557aa 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1808,7 +1808,7 @@ static void ftdi_read_bulk_callback(struct urb *urb)
 	if (port->port.count <= 0)
 		return;
 
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (!tty) {
 		dbg("%s - bad tty pointer - exiting", __func__);
 		return;
@@ -1817,7 +1817,7 @@ static void ftdi_read_bulk_callback(struct urb *urb)
 	priv = usb_get_serial_port_data(port);
 	if (!priv) {
 		dbg("%s - bad port private data pointer - exiting", __func__);
-		return;
+		goto out;
 	}
 
 	if (urb != port->read_urb)
@@ -1827,7 +1827,7 @@ static void ftdi_read_bulk_callback(struct urb *urb)
 		/* This will happen at close every time so it is a dbg not an
 		   err */
 		dbg("(this is ok on close) nonzero read bulk status received: %d", status);
-		return;
+		goto out;
 	}
 
 	/* count data bytes, but not status bytes */
@@ -1838,7 +1838,8 @@ static void ftdi_read_bulk_callback(struct urb *urb)
 	spin_unlock_irqrestore(&priv->rx_lock, flags);
 
 	ftdi_process_read(&priv->rx_work.work);
-
+out:
+	tty_kref_put(tty);
 } /* ftdi_read_bulk_callback */
 
 
@@ -1863,7 +1864,7 @@ static void ftdi_process_read(struct work_struct *work)
 	if (port->port.count <= 0)
 		return;
 
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (!tty) {
 		dbg("%s - bad tty pointer - exiting", __func__);
 		return;
@@ -1872,13 +1873,13 @@ static void ftdi_process_read(struct work_struct *work)
 	priv = usb_get_serial_port_data(port);
 	if (!priv) {
 		dbg("%s - bad port private data pointer - exiting", __func__);
-		return;
+		goto out;
 	}
 
 	urb = port->read_urb;
 	if (!urb) {
 		dbg("%s - bad read_urb pointer - exiting", __func__);
-		return;
+		goto out;
 	}
 
 	data = urb->transfer_buffer;
@@ -2020,7 +2021,7 @@ static void ftdi_process_read(struct work_struct *work)
 			schedule_delayed_work(&priv->rx_work, 1);
 		else
 			dbg("%s - port is closed", __func__);
-		return;
+		goto out;
 	}
 
 	/* urb is completely processed */
@@ -2041,6 +2042,8 @@ static void ftdi_process_read(struct work_struct *work)
 			err("%s - failed resubmitting read urb, error %d",
 							__func__, result);
 	}
+out:
+	tty_kref_put(tty);
 } /* ftdi_process_read */
 
 
diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
index d95382088075..2ad0569bcf19 100644
--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -276,7 +276,7 @@ static inline int isAbortTrfCmnd(const unsigned char *buf)
 static void send_to_tty(struct usb_serial_port *port,
 			char *data, unsigned int actual_length)
 {
-	struct tty_struct *tty = port->port.tty;
+	struct tty_struct *tty = tty_port_tty_get(&port->port);
 
 	if (tty && actual_length) {
 
@@ -287,6 +287,7 @@ static void send_to_tty(struct usb_serial_port *port,
 		tty_insert_flip_string(tty, data, actual_length);
 		tty_flip_buffer_push(tty);
 	}
+	tty_kref_put(tty);
 }
 
 
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index fe84c88ec20c..814909f1ee63 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -330,7 +330,7 @@ static void resubmit_read_urb(struct usb_serial_port *port, gfp_t mem_flags)
 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 {
 	struct urb *urb = port->read_urb;
-	struct tty_struct *tty = port->port.tty;
+	struct tty_struct *tty = tty_port_tty_get(&port->port);
 	int room;
 
 	/* Push data to tty */
@@ -341,6 +341,7 @@ static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 			tty_flip_buffer_push(tty);
 		}
 	}
+	tty_kref_put(tty);
 
 	resubmit_read_urb(port, GFP_ATOMIC);
 }
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index bfa508ddb0fe..611f97fd62f1 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -600,6 +600,7 @@ static void edge_interrupt_callback(struct urb *urb)
 	struct edgeport_serial	*edge_serial = urb->context;
 	struct edgeport_port *edge_port;
 	struct usb_serial_port *port;
+	struct tty_struct *tty;
 	unsigned char *data = urb->transfer_buffer;
 	int length = urb->actual_length;
 	int bytes_avail;
@@ -675,9 +676,12 @@ static void edge_interrupt_callback(struct urb *urb)
 
 					/* tell the tty driver that something
 					   has changed */
-					if (edge_port->port->port.tty)
-						tty_wakeup(edge_port->port->port.tty);
-
+					tty = tty_port_tty_get(
+						&edge_port->port->port);
+					if (tty) {
+						tty_wakeup(tty);
+						tty_kref_put(tty);
+					}
 					/* Since we have more credit, check
 					   if more data can be sent */
 					send_more_port_data(edge_serial,
@@ -778,13 +782,14 @@ static void edge_bulk_out_data_callback(struct urb *urb)
 		    __func__, status);
 	}
 
-	tty = edge_port->port->port.tty;
+	tty = tty_port_tty_get(&edge_port->port->port);
 
 	if (tty && edge_port->open) {
 		/* let the tty driver wakeup if it has a special
 		   write_wakeup function */
 		tty_wakeup(tty);
 	}
+	tty_kref_put(tty);
 
 	/* Release the Write URB */
 	edge_port->write_in_progress = false;
@@ -826,11 +831,12 @@ static void edge_bulk_out_cmd_callback(struct urb *urb)
 	}
 
 	/* Get pointer to tty */
-	tty = edge_port->port->port.tty;
+	tty = tty_port_tty_get(&edge_port->port->port);
 
 	/* tell the tty driver that something has changed */
 	if (tty && edge_port->open)
 		tty_wakeup(tty);
+	tty_kref_put(tty);
 
 	/* we have completed the command */
 	edge_port->commandPending = false;
@@ -1932,11 +1938,13 @@ static void process_rcvd_data(struct edgeport_serial *edge_serial,
 							edge_serial->rxPort];
 				edge_port = usb_get_serial_port_data(port);
 				if (edge_port->open) {
-					tty = edge_port->port->port.tty;
+					tty = tty_port_tty_get(
+						&edge_port->port->port);
 					if (tty) {
 						dbg("%s - Sending %d bytes to TTY for port %d",
 							__func__, rxLen, edge_serial->rxPort);
 						edge_tty_recv(&edge_serial->serial->dev->dev, tty, buffer, rxLen);
+						tty_kref_put(tty);
 					}
 					edge_port->icount.rx += rxLen;
 				}
@@ -1971,6 +1979,7 @@ static void process_rcvd_status(struct edgeport_serial *edge_serial,
 {
 	struct usb_serial_port *port;
 	struct edgeport_port *edge_port;
+	struct tty_struct *tty;
 	__u8 code = edge_serial->rxStatusCode;
 
 	/* switch the port pointer to the one being currently talked about */
@@ -2020,10 +2029,12 @@ static void process_rcvd_status(struct edgeport_serial *edge_serial,
 
 		/* send the current line settings to the port so we are
 		   in sync with any further termios calls */
-		/* FIXME: locking on tty */
-		if (edge_port->port->port.tty)
-			change_port_settings(edge_port->port->port.tty,
-				edge_port, edge_port->port->port.tty->termios);
+		tty = tty_port_tty_get(&edge_port->port->port);
+		if (tty) {
+			change_port_settings(tty,
+				edge_port, tty->termios);
+			tty_kref_put(tty);
+		}
 
 		/* we have completed the open */
 		edge_port->openPending = false;
@@ -2163,10 +2174,14 @@ static void handle_new_lsr(struct edgeport_port *edge_port, __u8 lsrData,
 	}
 
 	/* Place LSR data byte into Rx buffer */
-	if (lsrData && edge_port->port->port.tty)
-		edge_tty_recv(&edge_port->port->dev,
-					edge_port->port->port.tty, &data, 1);
-
+	if (lsrData) {
+		struct tty_struct *tty =
+				tty_port_tty_get(&edge_port->port->port);
+		if (tty) {
+			edge_tty_recv(&edge_port->port->dev, tty, &data, 1);
+			tty_kref_put(tty);
+		}
+	}
 	/* update input line counters */
 	icount = &edge_port->icount;
 	if (newLsr & LSR_BREAK)
diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index cb4c54316cf5..541dd8e6e7a2 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -572,7 +572,7 @@ static void chase_port(struct edgeport_port *port, unsigned long timeout,
 								int flush)
 {
 	int baud_rate;
-	struct tty_struct *tty = port->port->port.tty;
+	struct tty_struct *tty = tty_port_tty_get(&port->port->port);
 	wait_queue_t wait;
 	unsigned long flags;
 
@@ -599,6 +599,7 @@ static void chase_port(struct edgeport_port *port, unsigned long timeout,
 	if (flush)
 		edge_buf_clear(port->ep_out_buf);
 	spin_unlock_irqrestore(&port->ep_lock, flags);
+	tty_kref_put(tty);
 
 	/* wait for data to drain from the device */
 	timeout += jiffies;
@@ -1554,7 +1555,7 @@ static void handle_new_msr(struct edgeport_port *edge_port, __u8 msr)
 	/* Save the new modem status */
 	edge_port->shadow_msr = msr & 0xf0;
 
-	tty = edge_port->port->port.tty;
+	tty = tty_port_tty_get(&edge_port->port->port);
 	/* handle CTS flow control */
 	if (tty && C_CRTSCTS(tty)) {
 		if (msr & EDGEPORT_MSR_CTS) {
@@ -1564,6 +1565,7 @@ static void handle_new_msr(struct edgeport_port *edge_port, __u8 msr)
 			tty->hw_stopped = 1;
 		}
 	}
+	tty_kref_put(tty);
 
 	return;
 }
@@ -1574,6 +1576,7 @@ static void handle_new_lsr(struct edgeport_port *edge_port, int lsr_data,
 	struct async_icount *icount;
 	__u8 new_lsr = (__u8)(lsr & (__u8)(LSR_OVER_ERR | LSR_PAR_ERR |
 						LSR_FRM_ERR | LSR_BREAK));
+	struct tty_struct *tty;
 
 	dbg("%s - %02x", __func__, new_lsr);
 
@@ -1587,8 +1590,13 @@ static void handle_new_lsr(struct edgeport_port *edge_port, int lsr_data,
 		new_lsr &= (__u8)(LSR_OVER_ERR | LSR_BREAK);
 
 	/* Place LSR data byte into Rx buffer */
-	if (lsr_data && edge_port->port->port.tty)
-		edge_tty_recv(&edge_port->port->dev, edge_port->port->port.tty, &data, 1);
+	if (lsr_data) {
+		tty = tty_port_tty_get(&edge_port->port->port);
+		if (tty) {
+			edge_tty_recv(&edge_port->port->dev, tty, &data, 1);
+			tty_kref_put(tty);
+		}
+	}
 
 	/* update input line counters */
 	icount = &edge_port->icount;
@@ -1749,7 +1757,7 @@ static void edge_bulk_in_callback(struct urb *urb)
 		++data;
 	}
 
-	tty = edge_port->port->port.tty;
+	tty = tty_port_tty_get(&edge_port->port->port);
 	if (tty && urb->actual_length) {
 		usb_serial_debug_data(debug, &edge_port->port->dev,
 					__func__, urb->actual_length, data);
@@ -1761,6 +1769,7 @@ static void edge_bulk_in_callback(struct urb *urb)
 							urb->actual_length);
 		edge_port->icount.rx += urb->actual_length;
 	}
+	tty_kref_put(tty);
 
 exit:
 	/* continue read unless stopped */
@@ -1796,6 +1805,7 @@ static void edge_bulk_out_callback(struct urb *urb)
 	struct usb_serial_port *port = urb->context;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	int status = urb->status;
+	struct tty_struct *tty;
 
 	dbg("%s - port %d", __func__, port->number);
 
@@ -1818,7 +1828,9 @@ static void edge_bulk_out_callback(struct urb *urb)
 	}
 
 	/* send any buffered data */
-	edge_send(port->port.tty);
+	tty = tty_port_tty_get(&port->port);
+	edge_send(tty);
+	tty_kref_put(tty);
 }
 
 static int edge_open(struct tty_struct *tty,
@@ -1876,7 +1888,7 @@ static int edge_open(struct tty_struct *tty,
 
 	/* set up the port settings */
 	if (tty)
-		edge_set_termios(tty, port, port->port.tty->termios);
+		edge_set_termios(tty, port, tty->termios);
 
 	/* open up the port */
 
diff --git a/drivers/usb/serial/ipaq.c b/drivers/usb/serial/ipaq.c
index cd9a2e138c8b..2affa9c118b2 100644
--- a/drivers/usb/serial/ipaq.c
+++ b/drivers/usb/serial/ipaq.c
@@ -764,13 +764,14 @@ static void ipaq_read_bulk_callback(struct urb *urb)
 	usb_serial_debug_data(debug, &port->dev, __func__,
 						urb->actual_length, data);
 
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (tty && urb->actual_length) {
 		tty_buffer_request_room(tty, urb->actual_length);
 		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 		bytes_in += urb->actual_length;
 	}
+	tty_kref_put(tty);
 
 	/* Continue trying to always read  */
 	usb_fill_bulk_urb(port->read_urb, port->serial->dev,
diff --git a/drivers/usb/serial/ipw.c b/drivers/usb/serial/ipw.c
index a842025b9b57..480cac27d646 100644
--- a/drivers/usb/serial/ipw.c
+++ b/drivers/usb/serial/ipw.c
@@ -170,12 +170,13 @@ static void ipw_read_bulk_callback(struct urb *urb)
 	usb_serial_debug_data(debug, &port->dev, __func__,
 					urb->actual_length, data);
 
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (tty && urb->actual_length) {
 		tty_buffer_request_room(tty, urb->actual_length);
 		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 	}
+	tty_kref_put(tty);
 
 	/* Continue trying to always read  */
 	usb_fill_bulk_urb(port->read_urb, port->serial->dev,
diff --git a/drivers/usb/serial/ir-usb.c b/drivers/usb/serial/ir-usb.c
index e59155c6607d..45d4043e04ab 100644
--- a/drivers/usb/serial/ir-usb.c
+++ b/drivers/usb/serial/ir-usb.c
@@ -465,11 +465,12 @@ static void ir_read_bulk_callback(struct urb *urb)
 			ir_baud = *data & 0x0f;
 		usb_serial_debug_data(debug, &port->dev, __func__,
 						urb->actual_length, data);
- 		tty = port->port.tty;
+		tty = tty_port_tty_get(&port->port);
 		if (tty_buffer_request_room(tty, urb->actual_length - 1)) {
 			tty_insert_flip_string(tty, data+1, urb->actual_length - 1);
 			tty_flip_buffer_push(tty);
 		}
+		tty_kref_put(tty);
 
 		/*
 		 * No break here.
diff --git a/drivers/usb/serial/iuu_phoenix.c b/drivers/usb/serial/iuu_phoenix.c
index ddff37fa6339..53710aa7eadd 100644
--- a/drivers/usb/serial/iuu_phoenix.c
+++ b/drivers/usb/serial/iuu_phoenix.c
@@ -629,13 +629,14 @@ static void read_buf_callback(struct urb *urb)
 	}
 
 	dbg("%s - %i chars to write", __func__, urb->actual_length);
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (data == NULL)
 		dbg("%s - data is NULL !!!", __func__);
 	if (tty && urb->actual_length && data) {
 		tty_insert_flip_string(tty, data, urb->actual_length);
 		tty_flip_buffer_push(tty);
 	}
+	tty_kref_put(tty);
 	iuu_led_activity_on(urb);
 }
 
diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index 704716f6f6d3..15447af48691 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -430,7 +430,7 @@ static void	usa26_indat_callback(struct urb *urb)
 	}
 
 	port =  urb->context;
-	tty = port->port.tty;
+	tty = tty_port_tty_get(&port->port);
 	if (tty && urb->actual_length) {
 		/* 0x80 bit is error flag */
 		if ((data[0] & 0x80) == 0) {
@@ -459,6 +459,7 @@ static void	usa26_indat_callback(struct urb *urb)
 		}
 		tty_flip_buffer_push(tty);
 	}
+	tty_kref_put(tty);
 
 	/* Resubmit urb so we continue receiving */
 	urb->dev = port->serial->dev;
@@ -513,6 +514,7 @@ static void	usa26_instat_callback(struct urb *urb)
 	struct usb_serial			*serial;
 	struct usb_serial_port			*port;
 	struct keyspan_port_private	 	*p_priv;
+	struct tty_struct			*tty;
 	int old_dcd_state, err;
 	int status = urb->status;
 
@@ -553,12 +555,11 @@ static void	usa26_instat_callback(struct urb *urb)
 	p_priv->dcd_state = ((msg->gpia_dcd) ? 1 : 0);
 	p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-	if (port->port.tty && !C_CLOCAL(port->port.tty)
-	    && old_dcd_state != p_priv->dcd_state) {
-		if (old_dcd_state)
-			tty_hangup(port->port.tty);
-		/*  else */
-		/*	wake_up_interruptible(&p_priv->open_wait); */
+	if (old_dcd_state != p_priv->dcd_state) {
+		tty = tty_port_tty_get(&port->port);
+		if (tty && !C_CLOCAL(tty))
+			tty_hangup(tty);
+		tty_kref_put(tty);
 	}
 
 	/* Resubmit urb so we continue receiving */
@@ -604,11 +605,12 @@ static void usa28_indat_callback(struct urb *urb)
 		p_priv = usb_get_serial_port_data(port);
 		data = urb->transfer_buffer;
 
-		tty = port->port.tty;
-		if (urb->actual_length) {
+		tty =tty_port_tty_get(&port->port);
+		if (tty && urb->actual_length) {
 			tty_insert_flip_string(tty, data, urb->actual_length);
 			tty_flip_buffer_push(tty);
 		}
+