From 70bc126471af30bb115e635512dcf6d86fe6e29a Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@hurleysoftware.com>
Date: Wed, 6 Mar 2013 08:20:52 -0500
Subject: tty: Add safe tty throttle/unthrottle functions

The tty driver can become stuck throttled due to race conditions
between throttle and unthrottle, when the decision to throttle
or unthrottle is conditional. The following example helps to
illustrate the race:

  CPU 0                        |  CPU 1
                               |
if (condition A)               |
                               | <processing such that A not true>
                               | if (!condition A)
                               |     unthrottle()
    throttle()                 |
                               |

Note the converse is also possible; ie.,

  CPU 0                        |  CPU 1
                               |
                               | if (!condition A)
<processing such that A true>  |
if (condition A)               |
    throttle()                 |
                               |     unthrottle()
                               |

Add new throttle/unthrottle functions based on the familiar model
of task state and schedule/wake. For example,

    while (1) {
        tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
        if (!condition)
            break;
        if (!tty_throttle_safe(tty))
            break;
    }
    __tty_set_flow_change(tty, 0);

In this example, if an unthrottle occurs after the condition is
evaluated but before tty_throttle_safe(), then tty_throttle_safe()
will return non-zero, looping and forcing the re-evaluation of
condition.

Reported-by: Vincent Pillet <vincentx.pillet@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/tty.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'include/linux/tty.h')

diff --git a/include/linux/tty.h b/include/linux/tty.h
index c75d886b0307..189ca80494d1 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -258,6 +258,7 @@ struct tty_struct {
 	unsigned char warned:1;
 	unsigned char ctrl_status;	/* ctrl_lock */
 	unsigned int receive_room;	/* Bytes free for queue */
+	int flow_change;
 
 	struct tty_struct *link;
 	struct fasync_struct *fasync;
@@ -318,6 +319,21 @@ struct tty_file_private {
 
 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
 
+/* Values for tty->flow_change */
+#define TTY_THROTTLE_SAFE 1
+#define TTY_UNTHROTTLE_SAFE 2
+
+static inline void __tty_set_flow_change(struct tty_struct *tty, int val)
+{
+	tty->flow_change = val;
+}
+
+static inline void tty_set_flow_change(struct tty_struct *tty, int val)
+{
+	tty->flow_change = val;
+	smp_mb();
+}
+
 #ifdef CONFIG_TTY
 extern void console_init(void);
 extern void tty_kref_put(struct tty_struct *tty);
@@ -400,6 +416,8 @@ extern int tty_write_room(struct tty_struct *tty);
 extern void tty_driver_flush_buffer(struct tty_struct *tty);
 extern void tty_throttle(struct tty_struct *tty);
 extern void tty_unthrottle(struct tty_struct *tty);
+extern int tty_throttle_safe(struct tty_struct *tty);
+extern int tty_unthrottle_safe(struct tty_struct *tty);
 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
 extern void tty_driver_remove_tty(struct tty_driver *driver,
 				  struct tty_struct *tty);
-- 
cgit v1.2.3


From 6865ff222ccab371c04afce17aec1f7d70b17dbc Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Thu, 7 Mar 2013 13:12:27 +0100
Subject: TTY: do not warn about setting speed via SPD_*

The warning is there since 2.1.69 and we have not seen anybody
reporting it in the past decade. Remove the warning now.

tty_get_baud_rate can now be inline. This gives us one less
EXPORT_SYMBOL.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/tty_ioctl.c | 28 ----------------------------
 include/linux/tty.h     | 18 ++++++++++++++++--
 2 files changed, 16 insertions(+), 30 deletions(-)

(limited to 'include/linux/tty.h')

diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 132d452578bb..28715e48b2f7 100644
--- a/drivers/tty/tty_ioctl.c
+++ b/drivers/tty/tty_ioctl.c
@@ -478,34 +478,6 @@ void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud)
 }
 EXPORT_SYMBOL_GPL(tty_encode_baud_rate);
 
-/**
- *	tty_get_baud_rate	-	get tty bit rates
- *	@tty: tty to query
- *
- *	Returns the baud rate as an integer for this terminal. The
- *	termios lock must be held by the caller and the terminal bit
- *	flags may be updated.
- *
- *	Locking: none
- */
-
-speed_t tty_get_baud_rate(struct tty_struct *tty)
-{
-	speed_t baud = tty_termios_baud_rate(&tty->termios);
-
-	if (baud == 38400 && tty->alt_speed) {
-		if (!tty->warned) {
-			printk(KERN_WARNING "Use of setserial/setrocket to "
-					    "set SPD_* flags is deprecated\n");
-			tty->warned = 1;
-		}
-		baud = tty->alt_speed;
-	}
-
-	return baud;
-}
-EXPORT_SYMBOL(tty_get_baud_rate);
-
 /**
  *	tty_termios_copy_hw	-	copy hardware settings
  *	@new: New termios
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 189ca80494d1..63b62865c8e9 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -255,7 +255,6 @@ struct tty_struct {
 	int count;
 	struct winsize winsize;		/* termios mutex */
 	unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
-	unsigned char warned:1;
 	unsigned char ctrl_status;	/* ctrl_lock */
 	unsigned int receive_room;	/* Bytes free for queue */
 	int flow_change;
@@ -437,13 +436,28 @@ extern void tty_flush_to_ldisc(struct tty_struct *tty);
 extern void tty_buffer_free_all(struct tty_port *port);
 extern void tty_buffer_flush(struct tty_struct *tty);
 extern void tty_buffer_init(struct tty_port *port);
-extern speed_t tty_get_baud_rate(struct tty_struct *tty);
 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
 extern void tty_termios_encode_baud_rate(struct ktermios *termios,
 						speed_t ibaud, speed_t obaud);
 extern void tty_encode_baud_rate(struct tty_struct *tty,
 						speed_t ibaud, speed_t obaud);
+
+/**
+ *	tty_get_baud_rate	-	get tty bit rates
+ *	@tty: tty to query
+ *
+ *	Returns the baud rate as an integer for this terminal. The
+ *	termios lock must be held by the caller and the terminal bit
+ *	flags may be updated.
+ *
+ *	Locking: none
+ */
+static inline speed_t tty_get_baud_rate(struct tty_struct *tty)
+{
+	return tty_termios_baud_rate(&tty->termios);
+}
+
 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
 extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
-- 
cgit v1.2.3


From 6aad04f21374633bd8cecf25024553d1e11a9522 Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Thu, 7 Mar 2013 13:12:29 +0100
Subject: TTY: add tty_port_tty_wakeup helper

It allows for cleaning up on a considerable amount of places. They did
port_get, wakeup, kref_put. Now the only thing needed is to call
tty_port_tty_wakeup which does exactly that.

One exception is ifx6x60 where tty_wakeup was open-coded. We now call
tty_wakeup properly there.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/um/drivers/line.c                  |  8 +-------
 drivers/isdn/capi/capi.c                |  7 +------
 drivers/isdn/gigaset/interface.c        |  6 +-----
 drivers/net/usb/hso.c                   | 13 ++-----------
 drivers/s390/char/sclp_tty.c            |  9 ++-------
 drivers/s390/char/sclp_vt220.c          |  8 +-------
 drivers/staging/fwserial/fwserial.c     | 10 ++--------
 drivers/staging/serqt_usb2/serqt_usb2.c |  7 +------
 drivers/tty/ehv_bytechan.c              |  6 +-----
 drivers/tty/hvc/hvsi.c                  |  7 +------
 drivers/tty/nozomi.c                    |  6 +-----
 drivers/tty/serial/ifx6x60.c            | 33 ++-------------------------------
 drivers/tty/tty_port.c                  | 16 ++++++++++++++++
 drivers/usb/class/cdc-acm.c             |  7 +------
 drivers/usb/serial/digi_acceleport.c    | 17 +++--------------
 drivers/usb/serial/io_edgeport.c        | 28 +++++-----------------------
 drivers/usb/serial/keyspan_pda.c        |  6 ++----
 drivers/usb/serial/mos7720.c            |  8 ++------
 drivers/usb/serial/mos7840.c            |  7 ++-----
 drivers/usb/serial/ti_usb_3410_5052.c   |  7 ++-----
 drivers/usb/serial/usb-serial.c         | 10 +---------
 include/linux/tty.h                     |  1 +
 22 files changed, 51 insertions(+), 176 deletions(-)

(limited to 'include/linux/tty.h')

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index f1b38571f94e..cc206eda245c 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -248,7 +248,6 @@ static irqreturn_t line_write_interrupt(int irq, void *data)
 {
 	struct chan *chan = data;
 	struct line *line = chan->line;
-	struct tty_struct *tty;
 	int err;
 
 	/*
@@ -267,12 +266,7 @@ static irqreturn_t line_write_interrupt(int irq, void *data)
 	}
 	spin_unlock(&line->lock);
 
-	tty = tty_port_tty_get(&line->port);
-	if (tty == NULL)
-		return IRQ_NONE;
-
-	tty_wakeup(tty);
-	tty_kref_put(tty);
+	tty_port_tty_wakeup(&line->port);
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 89562a845f6a..ac6f72b455d1 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -569,7 +569,6 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
 {
 	struct capidev *cdev = ap->private;
 #ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
-	struct tty_struct *tty;
 	struct capiminor *mp;
 	u16 datahandle;
 	struct capincci *np;
@@ -627,11 +626,7 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
 			 CAPIMSG_U16(skb->data, CAPIMSG_BASELEN + 4 + 2));
 		kfree_skb(skb);
 		capiminor_del_ack(mp, datahandle);
-		tty = tty_port_tty_get(&mp->port);
-		if (tty) {
-			tty_wakeup(tty);
-			tty_kref_put(tty);
-		}
+		tty_port_tty_wakeup(&mp->port);
 		handle_minor_send(mp);
 
 	} else {
diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index e2b539675b66..600c79b030cd 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -487,12 +487,8 @@ static const struct tty_operations if_ops = {
 static void if_wake(unsigned long data)
 {
 	struct cardstate *cs = (struct cardstate *)data;
-	struct tty_struct *tty = tty_port_tty_get(&cs->port);
 
-	if (tty) {
-		tty_wakeup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_wakeup(&cs->port);
 }
 
 /*** interface to common ***/
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index e2dd3249b6bd..a7714b4f29ad 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1925,7 +1925,6 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 {
 	struct hso_serial *serial = urb->context;
 	int status = urb->status;
-	struct tty_struct *tty;
 
 	/* sanity check */
 	if (!serial) {
@@ -1941,11 +1940,7 @@ static void hso_std_serial_write_bulk_callback(struct urb *urb)
 		return;
 	}
 	hso_put_activity(serial->parent);
-	tty = tty_port_tty_get(&serial->port);
-	if (tty) {
-		tty_wakeup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_wakeup(&serial->port);
 	hso_kick_transmit(serial);
 
 	D1(" ");
@@ -2008,12 +2003,8 @@ static void ctrl_callback(struct urb *urb)
 		put_rxbuf_data_and_resubmit_ctrl_urb(serial);
 		spin_unlock(&serial->serial_lock);
 	} else {
-		struct tty_struct *tty = tty_port_tty_get(&serial->port);
 		hso_put_activity(serial->parent);
-		if (tty) {
-			tty_wakeup(tty);
-			tty_kref_put(tty);
-		}
+		tty_port_tty_wakeup(&serial->port);
 		/* response to a write command */
 		hso_kick_transmit(serial);
 	}
diff --git a/drivers/s390/char/sclp_tty.c b/drivers/s390/char/sclp_tty.c
index 14b4cb8abcc8..7ed7a5987816 100644
--- a/drivers/s390/char/sclp_tty.c
+++ b/drivers/s390/char/sclp_tty.c
@@ -107,7 +107,6 @@ sclp_tty_write_room (struct tty_struct *tty)
 static void
 sclp_ttybuf_callback(struct sclp_buffer *buffer, int rc)
 {
-	struct tty_struct *tty;
 	unsigned long flags;
 	void *page;
 
@@ -125,12 +124,8 @@ sclp_ttybuf_callback(struct sclp_buffer *buffer, int rc)
 					    struct sclp_buffer, list);
 		spin_unlock_irqrestore(&sclp_tty_lock, flags);
 	} while (buffer && sclp_emit_buffer(buffer, sclp_ttybuf_callback));
-	/* check if the tty needs a wake up call */
-	tty = tty_port_tty_get(&sclp_port);
-	if (tty != NULL) {
-		tty_wakeup(tty);
-		tty_kref_put(tty);
-	}
+
+	tty_port_tty_wakeup(&sclp_port);
 }
 
 static inline void
diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index 6c92f62623be..5aaaa2ec8df4 100644
--- a/drivers/s390/char/sclp_vt220.c
+++ b/drivers/s390/char/sclp_vt220.c
@@ -114,7 +114,6 @@ static struct sclp_register sclp_vt220_register = {
 static void
 sclp_vt220_process_queue(struct sclp_vt220_request *request)
 {
-	struct tty_struct *tty;
 	unsigned long flags;
 	void *page;
 
@@ -139,12 +138,7 @@ sclp_vt220_process_queue(struct sclp_vt220_request *request)
 	} while (__sclp_vt220_emit(request));
 	if (request == NULL && sclp_vt220_flush_later)
 		sclp_vt220_emit_current();
-	/* Check if the tty needs a wake up call */
-	tty = tty_port_tty_get(&sclp_vt220_port);
-	if (tty) {
-		tty_wakeup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_wakeup(&sclp_vt220_port);
 }
 
 #define SCLP_BUFFER_MAX_RETRY		1
diff --git a/drivers/staging/fwserial/fwserial.c b/drivers/staging/fwserial/fwserial.c
index 5a6fb44f38a8..5c64e3a35b28 100644
--- a/drivers/staging/fwserial/fwserial.c
+++ b/drivers/staging/fwserial/fwserial.c
@@ -744,7 +744,6 @@ static void fwtty_tx_complete(struct fw_card *card, int rcode,
 			      struct fwtty_transaction *txn)
 {
 	struct fwtty_port *port = txn->port;
-	struct tty_struct *tty;
 	int len;
 
 	fwtty_dbg(port, "rcode: %d", rcode);
@@ -769,13 +768,8 @@ static void fwtty_tx_complete(struct fw_card *card, int rcode,
 		port->stats.dropped += txn->dma_pended.len;
 	}
 
-	if (len < WAKEUP_CHARS) {
-		tty = tty_port_tty_get(&port->port);
-		if (tty) {
-			tty_wakeup(tty);
-			tty_kref_put(tty);
-		}
-	}
+	if (len < WAKEUP_CHARS)
+		tty_port_tty_wakeup(&port->port);
 }
 
 static int fwtty_tx(struct fwtty_port *port, bool drain)
diff --git a/drivers/staging/serqt_usb2/serqt_usb2.c b/drivers/staging/serqt_usb2/serqt_usb2.c
index b1bb1a6abe81..8a6e5ea476e1 100644
--- a/drivers/staging/serqt_usb2/serqt_usb2.c
+++ b/drivers/staging/serqt_usb2/serqt_usb2.c
@@ -264,7 +264,6 @@ static void ProcessRxChar(struct usb_serial_port *port, unsigned char data)
 
 static void qt_write_bulk_callback(struct urb *urb)
 {
-	struct tty_struct *tty;
 	int status;
 	struct quatech_port *quatech_port;
 
@@ -278,11 +277,7 @@ static void qt_write_bulk_callback(struct urb *urb)
 
 	quatech_port = urb->context;
 
-	tty = tty_port_tty_get(&quatech_port->port->port);
-
-	if (tty)
-		tty_wakeup(tty);
-	tty_kref_put(tty);
+	tty_port_tty_wakeup(&quatech_port->port->port);
 }
 
 static void qt_interrupt_callback(struct urb *urb)
diff --git a/drivers/tty/ehv_bytechan.c b/drivers/tty/ehv_bytechan.c
index ed92622b8949..6d0c27cd03da 100644
--- a/drivers/tty/ehv_bytechan.c
+++ b/drivers/tty/ehv_bytechan.c
@@ -472,13 +472,9 @@ static void ehv_bc_tx_dequeue(struct ehv_bc_data *bc)
 static irqreturn_t ehv_bc_tty_tx_isr(int irq, void *data)
 {
 	struct ehv_bc_data *bc = data;
-	struct tty_struct *ttys = tty_port_tty_get(&bc->port);
 
 	ehv_bc_tx_dequeue(bc);
-	if (ttys) {
-		tty_wakeup(ttys);
-		tty_kref_put(ttys);
-	}
+	tty_port_tty_wakeup(&bc->port);
 
 	return IRQ_HANDLED;
 }
diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c
index ef95a154854a..41901997c0d6 100644
--- a/drivers/tty/hvc/hvsi.c
+++ b/drivers/tty/hvc/hvsi.c
@@ -861,7 +861,6 @@ static void hvsi_write_worker(struct work_struct *work)
 {
 	struct hvsi_struct *hp =
 		container_of(work, struct hvsi_struct, writer.work);
-	struct tty_struct *tty;
 	unsigned long flags;
 #ifdef DEBUG
 	static long start_j = 0;
@@ -895,11 +894,7 @@ static void hvsi_write_worker(struct work_struct *work)
 		start_j = 0;
 #endif /* DEBUG */
 		wake_up_all(&hp->emptyq);
-		tty = tty_port_tty_get(&hp->port);
-		if (tty) {
-			tty_wakeup(tty);
-			tty_kref_put(tty);
-		}
+		tty_port_tty_wakeup(&hp->port);
 	}
 
 out:
diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index 2dff19796157..2e5bbdc09e1c 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -791,7 +791,6 @@ static int send_data(enum port_type index, struct nozomi *dc)
 	const u8 toggle = port->toggle_ul;
 	void __iomem *addr = port->ul_addr[toggle];
 	const u32 ul_size = port->ul_size[toggle];
-	struct tty_struct *tty = tty_port_tty_get(&port->port);
 
 	/* Get data from tty and place in buf for now */
 	size = kfifo_out(&port->fifo_ul, dc->send_buf,
@@ -799,7 +798,6 @@ static int send_data(enum port_type index, struct nozomi *dc)
 
 	if (size == 0) {
 		DBG4("No more data to send, disable link:");
-		tty_kref_put(tty);
 		return 0;
 	}
 
@@ -809,10 +807,8 @@ static int send_data(enum port_type index, struct nozomi *dc)
 	write_mem32(addr, (u32 *) &size, 4);
 	write_mem32(addr + 4, (u32 *) dc->send_buf, size);
 
-	if (tty)
-		tty_wakeup(tty);
+	tty_port_tty_wakeup(&port->port);
 
-	tty_kref_put(tty);
 	return 1;
 }
 
diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c
index 68d7ce997ede..d723d4193b90 100644
--- a/drivers/tty/serial/ifx6x60.c
+++ b/drivers/tty/serial/ifx6x60.c
@@ -442,25 +442,6 @@ static void ifx_spi_setup_spi_header(unsigned char *txbuffer, int tx_count,
 	txbuffer[1] |= (more << IFX_SPI_MORE_BIT) & IFX_SPI_MORE_MASK;
 }
 
-/**
- *	ifx_spi_wakeup_serial	-	SPI space made
- *	@port_data: our SPI device
- *
- *	We have emptied the FIFO enough that we want to get more data
- *	queued into it. Poke the line discipline via tty_wakeup so that
- *	it will feed us more bits
- */
-static void ifx_spi_wakeup_serial(struct ifx_spi_device *ifx_dev)
-{
-	struct tty_struct *tty;
-
-	tty = tty_port_tty_get(&ifx_dev->tty_port);
-	if (!tty)
-		return;
-	tty_wakeup(tty);
-	tty_kref_put(tty);
-}
-
 /**
  *	ifx_spi_prepare_tx_buffer	-	prepare transmit frame
  *	@ifx_dev: our SPI device
@@ -506,7 +487,7 @@ static int ifx_spi_prepare_tx_buffer(struct ifx_spi_device *ifx_dev)
 			tx_count += temp_count;
 			if (temp_count == queue_length)
 				/* poke port to get more data */
-				ifx_spi_wakeup_serial(ifx_dev);
+				tty_port_tty_wakeup(&ifx_dev->tty_port);
 			else /* more data in port, use next SPI message */
 				ifx_dev->spi_more = 1;
 		}
@@ -683,8 +664,6 @@ static void ifx_spi_insert_flip_string(struct ifx_spi_device *ifx_dev,
 static void ifx_spi_complete(void *ctx)
 {
 	struct ifx_spi_device *ifx_dev = ctx;
-	struct tty_struct *tty;
-	struct tty_ldisc *ldisc = NULL;
 	int length;
 	int actual_length;
 	unsigned char more;
@@ -762,15 +741,7 @@ complete_exit:
 			 */
 			ifx_spi_power_state_clear(ifx_dev,
 						  IFX_SPI_POWER_DATA_PENDING);
-			tty = tty_port_tty_get(&ifx_dev->tty_port);
-			if (tty) {
-				ldisc = tty_ldisc_ref(tty);
-				if (ldisc) {
-					ldisc->ops->write_wakeup(tty);
-					tty_ldisc_deref(ldisc);
-				}
-				tty_kref_put(tty);
-			}
+			tty_port_tty_wakeup(&ifx_dev->tty_port);
 		}
 	}
 }
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index b7ff59d3db88..8bb757c62ee2 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -232,6 +232,22 @@ void tty_port_hangup(struct tty_port *port)
 }
 EXPORT_SYMBOL(tty_port_hangup);
 
+/**
+ * tty_port_tty_wakeup - helper to wake up a tty
+ *
+ * @port: tty port
+ */
+void tty_port_tty_wakeup(struct tty_port *port)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+
+	if (tty) {
+		tty_wakeup(tty);
+		tty_kref_put(tty);
+	}
+}
+EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
+
 /**
  *	tty_port_carrier_raised	-	carrier raised check
  *	@port: tty port
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 8ac25adf31b4..755766e4b756 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -475,15 +475,10 @@ static void acm_write_bulk(struct urb *urb)
 static void acm_softint(struct work_struct *work)
 {
 	struct acm *acm = container_of(work, struct acm, work);
-	struct tty_struct *tty;
 
 	dev_vdbg(&acm->data->dev, "%s\n", __func__);
 
-	tty = tty_port_tty_get(&acm->port);
-	if (!tty)
-		return;
-	tty_wakeup(tty);
-	tty_kref_put(tty);
+	tty_port_tty_wakeup(&acm->port);
 }
 
 /*
diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index ebe45fa0ed50..31191581060c 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -210,7 +210,6 @@ struct digi_port {
 
 /* Local Function Declarations */
 
-static void digi_wakeup_write(struct usb_serial_port *port);
 static void digi_wakeup_write_lock(struct work_struct *work);
 static int digi_write_oob_command(struct usb_serial_port *port,
 	unsigned char *buf, int count, int interruptible);
@@ -374,20 +373,10 @@ static void digi_wakeup_write_lock(struct work_struct *work)
 	unsigned long flags;
 
 	spin_lock_irqsave(&priv->dp_port_lock, flags);
-	digi_wakeup_write(port);
+	tty_port_tty_wakeup(&port->port);
 	spin_unlock_irqrestore(&priv->dp_port_lock, flags);
 }
 
-static void digi_wakeup_write(struct usb_serial_port *port)
-{
-	struct tty_struct *tty = tty_port_tty_get(&port->port);
-	if (tty) {
-		tty_wakeup(tty);
-		tty_kref_put(tty);
-	}
-}
-
-
 /*
  *  Digi Write OOB Command
  *
@@ -1044,7 +1033,7 @@ static void digi_write_bulk_callback(struct urb *urb)
 		}
 	}
 	/* wake up processes sleeping on writes immediately */
-	digi_wakeup_write(port);
+	tty_port_tty_wakeup(&port->port);
 	/* also queue up a wakeup at scheduler time, in case we */
 	/* lost the race in write_chan(). */
 	schedule_work(&priv->dp_wakeup_work);
@@ -1522,7 +1511,7 @@ static int digi_read_oob_callback(struct urb *urb)
 				/* port must be open to use tty struct */
 				if (rts) {
 					tty->hw_stopped = 0;
-					digi_wakeup_write(port);
+					tty_port_tty_wakeup(&port->port);
 				}
 			} else {
 				priv->dp_modem_signals &= ~TIOCM_CTS;
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index b00e5cbf741f..44e5208f7c61 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -565,7 +565,6 @@ static void edge_interrupt_callback(struct urb *urb)
 	struct device *dev;
 	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;
@@ -644,12 +643,7 @@ static void edge_interrupt_callback(struct urb *urb)
 
 					/* tell the tty driver that something
 					   has changed */
-					tty = tty_port_tty_get(
-						&edge_port->port->port);
-					if (tty) {
-						tty_wakeup(tty);
-						tty_kref_put(tty);
-					}
+					tty_port_tty_wakeup(&edge_port->port->port);
 					/* Since we have more credit, check
 					   if more data can be sent */
 					send_more_port_data(edge_serial,
@@ -738,7 +732,6 @@ static void edge_bulk_in_callback(struct urb *urb)
 static void edge_bulk_out_data_callback(struct urb *urb)
 {
 	struct edgeport_port *edge_port = urb->context;
-	struct tty_struct *tty;
 	int status = urb->status;
 
 	if (status) {
@@ -747,14 +740,8 @@ static void edge_bulk_out_data_callback(struct urb *urb)
 			__func__, status);
 	}
 
-	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);
+	if (edge_port->open)
+		tty_port_tty_wakeup(&edge_port->port->port);
 
 	/* Release the Write URB */
 	edge_port->write_in_progress = false;
@@ -773,7 +760,6 @@ static void edge_bulk_out_data_callback(struct urb *urb)
 static void edge_bulk_out_cmd_callback(struct urb *urb)
 {
 	struct edgeport_port *edge_port = urb->context;
-	struct tty_struct *tty;
 	int status = urb->status;
 
 	atomic_dec(&CmdUrbs);
@@ -794,13 +780,9 @@ static void edge_bulk_out_cmd_callback(struct urb *urb)
 		return;
 	}
 
-	/* Get pointer to 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);
+	if (edge_port->open)
+		tty_port_tty_wakeup(&edge_port->port->port);
 
 	/* we have completed the command */
 	edge_port->commandPending = false;
diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 3b17d5d13dc8..2230223978ca 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -104,10 +104,8 @@ static void keyspan_pda_wakeup_write(struct work_struct *work)
 	struct keyspan_pda_private *priv =
 		container_of(work, struct keyspan_pda_private, wakeup_work);
 	struct usb_serial_port *port = priv->port;
-	struct tty_struct *tty = tty_port_tty_get(&port->port);
-	if (tty)
-		tty_wakeup(tty);
-	tty_kref_put(tty);
+
+	tty_port_tty_wakeup(&port->port);
 }
 
 static void keyspan_pda_request_unthrottle(struct work_struct *work)
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index e0ebec3b5d6a..e956eae198fd 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -932,7 +932,6 @@ static void mos7720_bulk_in_callback(struct urb *urb)
 static void mos7720_bulk_out_data_callback(struct urb *urb)
 {
 	struct moschip_port *mos7720_port;
-	struct tty_struct *tty;
 	int status = urb->status;
 
 	if (status) {
@@ -946,11 +945,8 @@ static void mos7720_bulk_out_data_callback(struct urb *urb)
 		return ;
 	}
 
-	tty = tty_port_tty_get(&mos7720_port->port->port);
-
-	if (tty && mos7720_port->open)
-		tty_wakeup(tty);
-	tty_kref_put(tty);
+	if (mos7720_port->open)
+		tty_port_tty_wakeup(&mos7720_port->port->port);
 }
 
 /*
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 809fb329eca5..08284d28e84b 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -814,7 +814,6 @@ static void mos7840_bulk_out_data_callback(struct urb *urb)
 {
 	struct moschip_port *mos7840_port;
 	struct usb_serial_port *port;
-	struct tty_struct *tty;
 	int status = urb->status;
 	int i;
 
@@ -837,10 +836,8 @@ static void mos7840_bulk_out_data_callback(struct urb *urb)
 	if (mos7840_port_paranoia_check(port, __func__))
 		return;
 
-	tty = tty_port_tty_get(&port->port);
-	if (tty && mos7840_port->open)
-		tty_wakeup(tty);
-	tty_kref_put(tty);
+	if (mos7840_port->open)
+		tty_port_tty_wakeup(&port->port);
 
 }
 
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 39cb9b807c3c..437f2d579cde 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -1227,7 +1227,6 @@ static void ti_send(struct ti_port *tport)
 {
 	int count, result;
 	struct usb_serial_port *port = tport->tp_port;
-	struct tty_struct *tty = tty_port_tty_get(&port->port);	/* FIXME */
 	unsigned long flags;
 
 	spin_lock_irqsave(&tport->tp_lock, flags);
@@ -1268,14 +1267,12 @@ static void ti_send(struct ti_port *tport)
 	}
 
 	/* more room in the buffer for new writes, wakeup */
-	if (tty)
-		tty_wakeup(tty);
-	tty_kref_put(tty);
+	tty_port_tty_wakeup(&port->port);
+
 	wake_up_interruptible(&tport->tp_write_wait);
 	return;
 unlock:
 	spin_unlock_irqrestore(&tport->tp_lock, flags);
-	tty_kref_put(tty);
 	return;
 }
 
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index a19ed74d770d..2df84845bafb 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -541,16 +541,8 @@ static void usb_serial_port_work(struct work_struct *work)
 {
 	struct usb_serial_port *port =
 		container_of(work, struct usb_serial_port, work);
-	struct tty_struct *tty;
 
-	tty = tty_port_tty_get(&port->port);
-	if (!tty)
-		return;
-
-	dev_dbg(tty->dev, "%s - port %d\n", __func__, port->number);
-
-	tty_wakeup(tty);
-	tty_kref_put(tty);
+	tty_port_tty_wakeup(&port->port);
 }
 
 static void kill_traffic(struct usb_serial_port *port)
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 63b62865c8e9..b6e890a87eb1 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -534,6 +534,7 @@ extern int tty_port_carrier_raised(struct tty_port *port);
 extern void tty_port_raise_dtr_rts(struct tty_port *port);
 extern void tty_port_lower_dtr_rts(struct tty_port *port);
 extern void tty_port_hangup(struct tty_port *port);
+extern void tty_port_tty_wakeup(struct tty_port *port);
 extern int tty_port_block_til_ready(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp);
 extern int tty_port_close_start(struct tty_port *port,
-- 
cgit v1.2.3


From aa27a094e2c2e0cc59914e56113b860f524f4479 Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Thu, 7 Mar 2013 13:12:30 +0100
Subject: TTY: add tty_port_tty_hangup helper

It allows for cleaning up on a considerable amount of places. They did
port_get, hangup, kref_put. Now the only thing needed is to call
tty_port_tty_hangup which does exactly that. And they can also decide
whether to consider CLOCAL or completely ignore that.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/um/drivers/chan_kern.c         |  6 +-----
 drivers/mmc/card/sdio_uart.c        | 13 ++---------
 drivers/net/usb/hso.c               |  7 +-----
 drivers/tty/cyclades.c              | 10 ++-------
 drivers/tty/moxa.c                  | 19 ++++++----------
 drivers/tty/n_gsm.c                 |  6 +-----
 drivers/tty/nozomi.c                |  9 +++-----
 drivers/tty/rocket.c                |  7 +-----
 drivers/tty/serial/ifx6x60.c        | 21 ++----------------
 drivers/tty/tty_port.c              | 17 +++++++++++++++
 drivers/usb/class/cdc-acm.c         | 24 ++++++---------------
 drivers/usb/serial/keyspan.c        | 43 +++++++++----------------------------
 drivers/usb/serial/option.c         |  9 ++------
 drivers/usb/serial/sierra.c         |  8 ++-----
 include/linux/tty.h                 |  1 +
 net/irda/ircomm/ircomm_tty_attach.c |  6 +-----
 16 files changed, 58 insertions(+), 148 deletions(-)

(limited to 'include/linux/tty.h')

diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
index 15c553c239a1..bf42825ba54f 100644
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -568,11 +568,7 @@ void chan_interrupt(struct line *line, int irq)
 		reactivate_fd(chan->fd, irq);
 	if (err == -EIO) {
 		if (chan->primary) {
-			struct tty_struct *tty = tty_port_tty_get(&line->port);
-			if (tty != NULL) {
-				tty_hangup(tty);
-				tty_kref_put(tty);
-			}
+			tty_port_tty_hangup(&line->port, false);
 			if (line->chan_out != chan)
 				close_one_chan(line->chan_out, 1);
 		}
diff --git a/drivers/mmc/card/sdio_uart.c b/drivers/mmc/card/sdio_uart.c
index c931dfe6a59c..f093cea0d060 100644
--- a/drivers/mmc/card/sdio_uart.c
+++ b/drivers/mmc/card/sdio_uart.c
@@ -134,7 +134,6 @@ static void sdio_uart_port_put(struct sdio_uart_port *port)
 static void sdio_uart_port_remove(struct sdio_uart_port *port)
 {
 	struct sdio_func *func;
-	struct tty_struct *tty;
 
 	BUG_ON(sdio_uart_table[port->index] != port);
 
@@ -155,12 +154,8 @@ static void sdio_uart_port_remove(struct sdio_uart_port *port)
 	sdio_claim_host(func);
 	port->func = NULL;
 	mutex_unlock(&port->func_lock);
-	tty = tty_port_tty_get(&port->port);
 	/* tty_hangup is async so is this safe as is ?? */
-	if (tty) {
-		tty_hangup(tty);
-		tty_kref_put(tty);
-	}
+	tty_port_tty_hangup(&port->port, false);
 	mutex_unlock(&port->port.mutex);
 	sdio_release_irq(func);
 	sdio_disable_func(func);
@@ -492,11 +487,7 @@ static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
 			wake_up_interruptible(&port->port.open_wait);
 		else {
 			/* DCD drop - hang up if tty attached */
-			tty = tty_port_tty_get(&port->port);
-			if (tty) {
-				tty_hangup(tty);
-				tty_kref_put(tty);
-			}
+			tty_port_tty_hangup(&port->port, false);
 		}
 	}
 	if (status & UART_MSR_DCTS) {
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index a7714b4f29ad..cba1d46e672e 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -3124,18 +3124,13 @@ static void hso_serial_ref_free(struct kref *ref)
 static void hso_free_interface(struct usb_interface *interface)
 {
 	struct hso_serial *hso_dev;
-	struct tty_struct *tty;
 	int i;
 
 	for (i = 0; i < HSO_SERIAL_TTY_MINORS; i++) {
 		if (serial_table[i] &&
 		    (serial_table[i]->interface == interface)) {
 			hso_dev = dev2ser(serial_table[i]);
-			tty = tty_port_tty_get(&hso_dev->port);
-			if (tty) {
-				tty_hangup(tty);
-				tty_kref_put(tty);
-			}
+			tty_port_tty_hangup(&hso_dev->port, false);
 			mutex_lock(&hso_dev->parent->mutex);
 			hso_dev->parent->usb_gone = 1;
 			mutex_unlock(&hso_dev->parent->mutex);
diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index 345bd0e0884e..33f83fee9fae 100644
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -1124,14 +1124,8 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
 					readl(&info->u.cyz.ch_ctrl->rs_status);
 				if (dcd & C_RS_DCD)
 					wake_up_interruptible(&info->port.open_wait);
-				else {
-					struct tty_struct *tty;
-					tty = tty_port_tty_get(&info->port);
-					if (tty) {
-						tty_hangup(tty);
-						tty_kref_put(tty);
-					}
-				}
+				else
+					tty_port_tty_hangup(&info->port, false);
 			}
 			break;
 		case C_CM_MCTS:
diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c
index adeac255e526..1deaca4674e4 100644
--- a/drivers/tty/moxa.c
+++ b/drivers/tty/moxa.c
@@ -913,16 +913,12 @@ static void moxa_board_deinit(struct moxa_board_conf *brd)
 
 	/* pci hot-un-plug support */
 	for (a = 0; a < brd->numPorts; a++)
-		if (brd->ports[a].port.flags & ASYNC_INITIALIZED) {
-			struct tty_struct *tty = tty_port_tty_get(
-						&brd->ports[a].port);
-			if (tty) {
-				tty_hangup(tty);
-				tty_kref_put(tty);
-			}
-		}
+		if (brd->ports[a].port.flags & ASYNC_INITIALIZED)
+			tty_port_tty_hangup(&brd->ports[a].port, false);
+
 	for (a = 0; a < MAX_PORTS_PER_BOARD; a++)
 		tty_port_destroy(&brd->ports[a].port);
+
 	while (1) {
 		opened = 0;
 		for (a = 0; a < brd->numPorts; a++)
@@ -1365,7 +1361,6 @@ static void moxa_hangup(struct tty_struct *tty)
 
 static void moxa_new_dcdstate(struct moxa_port *p, u8 dcd)
 {
-	struct tty_struct *tty;
 	unsigned long flags;
 	dcd = !!dcd;
 
@@ -1373,10 +1368,8 @@ static void moxa_new_dcdstate(struct moxa_port *p, u8 dcd)
 	if (dcd != p->DCDState) {
         	p->DCDState = dcd;
         	spin_unlock_irqrestore(&p->port.lock, flags);
-		tty = tty_port_tty_get(&p->port);
-		if (tty && !C_CLOCAL(tty) && !dcd)
-			tty_hangup(tty);
-		tty_kref_put(tty);
+		if (!dcd)
+			tty_port_tty_hangup(&p->port, true);
 	}
 	else
 		spin_unlock_irqrestore(&p->port.lock, flags);
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 4a43ef5d7962..74d9a0258d7c 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -1418,11 +1418,7 @@ static void gsm_dlci_close(struct gsm_dlci *dlci)
 		pr_debug("DLCI %d goes closed.\n", dlci->addr);
 	dlci->state = DLCI_CLOSED;
 	if (dlci->addr != 0) {
-		struct tty_struct  *tty = tty_port_tty_get(&dlci->port);
-		if (tty) {
-			tty_hangup(tty);
-			tty_kref_put(tty);
-		}
+		tty_port_tty_hangup(&dlci->port, false);
 		kfifo_reset(dlci->fifo);
 	} else
 		dlci->gsm->dead = 1;
diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index 2e5bbdc09e1c..d6080c3831ef 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -1501,12 +1501,9 @@ static void tty_exit(struct nozomi *dc)
 
 	DBG1(" ");
 
-	for (i = 0; i < MAX_PORT; ++i) {
-		struct tty_struct *tty = tty_port_tty_get(&dc->port[i].port);
-		if (tty && list_empty(&tty->hangup_work.entry))
-			tty_hangup(tty);
-		tty_kref_put(tty);
-	}
+	for (i = 0; i < MAX_PORT; ++i)
+		tty_port_tty_hangup(&dc->port[i].port, false);
+
 	/* Racy below - surely should wait for scheduled work to be done or
 	   complete off a hangup method ? */
 	while (dc->open_ttys)
diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index 1d270034bfc3..bbffd7a431e9 100644
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -521,15 +521,10 @@ static void rp_handle_port(struct r_port *info)
 		       (ChanStatus & CD_ACT) ? "on" : "off");
 #endif
 		if (!(ChanStatus & CD_ACT) && info->cd_status) {
-			struct tty_struct *tty;
 #ifdef ROCKET_DEBUG_HANGUP
 			printk(KERN_INFO "CD drop, calling hangup.\n");
 #endif
-			tty = tty_port_tty_get(&info->port);
-			if (tty) {
-				tty_hangup(tty);
-				tty_kref_put(tty);
-			}
+			tty_port_tty_hangup(&info->port, false);
 		}
 		info->cd_status = (ChanStatus & CD_ACT) ? 1 : 0;
 		wake_up_interruptible(&info->port.open_wait);
diff --git a/drivers/tty/serial/ifx6x60.c b/drivers/tty/serial/ifx6x60.c
index d723d4193b90..2c77fed31a72 100644
--- a/drivers/tty/serial/ifx6x60.c
+++ b/drivers/tty/serial/ifx6x60.c
@@ -269,23 +269,6 @@ static void mrdy_assert(struct ifx_spi_device *ifx_dev)
 	mrdy_set_high(ifx_dev);
 }
 
-/**
- *	ifx_spi_hangup		-	hang up an IFX device
- *	@ifx_dev: our SPI device
- *
- *	Hang up the tty attached to the IFX device if one is currently
- *	open. If not take no action
- */
-static void ifx_spi_ttyhangup(struct ifx_spi_device *ifx_dev)
-{
-	struct tty_port *pport = &ifx_dev->tty_port;
-	struct tty_struct *tty = tty_port_tty_get(pport);
-	if (tty) {
-		tty_hangup(tty);
-		tty_kref_put(tty);
-	}
-}
-
 /**
  *	ifx_spi_timeout		-	SPI timeout
  *	@arg: our SPI device
@@ -298,7 +281,7 @@ static void ifx_spi_timeout(unsigned long arg)
 	struct ifx_spi_device *ifx_dev = (struct ifx_spi_device *)arg;
 
 	dev_warn(&ifx_dev->spi_dev->dev, "*** SPI Timeout ***");
-	ifx_spi_ttyhangup(ifx_dev);
+	tty_port_tty_hangup(&ifx_dev->tty_port, false);
 	mrdy_set_low(ifx_dev);
 	clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
 }
@@ -933,7 +916,7 @@ static irqreturn_t ifx_spi_reset_interrupt(int irq, void *dev)
 		set_bit(MR_INPROGRESS, &ifx_dev->mdm_reset_state);
 		if (!solreset) {
 			/* unsolicited reset  */
-			ifx_spi_ttyhangup(ifx_dev);
+			tty_port_tty_hangup(&ifx_dev->tty_port, false);
 		}
 	} else {
 		/* exited reset */
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 8bb757c62ee2..7f38eeaafac3 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -232,6 +232,23 @@ void tty_port_hangup(struct tty_port *port)
 }
 EXPORT_SYMBOL(tty_port_hangup);
 
+/**
+ * tty_port_tty_hangup - helper to hang up a tty
+ *
+ * @port: tty port
+ * @check_clocal: hang only ttys with CLOCAL unset?
+ */
+void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
+{
+	struct tty_struct *tty = tty_port_tty_get(port);
+
+	if (tty && (!check_clocal || !C_CLOCAL(tty))) {
+		tty_hangup(tty);
+		tty_kref_put(tty);
+	}
+}
+EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
+
 /**
  * tty_port_tty_wakeup - helper to wake up a tty
  *
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 755766e4b756..27a18743275e 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -292,7 +292,6 @@ static void acm_ctrl_irq(struct urb *urb)
 {
 	struct acm *acm = urb->context;
 	struct usb_cdc_notification *dr = urb->transfer_buffer;
-	struct tty_struct *tty;
 	unsigned char *data;
 	int newctrl;
 	int retval;
@@ -327,17 +326,12 @@ static void acm_ctrl_irq(struct urb *urb)
 		break;
 
 	case USB_CDC_NOTIFY_SERIAL_STATE:
-		tty = tty_port_tty_get(&acm->port);
 		newctrl = get_unaligned_le16(data);
 
-		if (tty) {
-			if (!acm->clocal &&
-				(acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) {
-				dev_dbg(&acm->control->dev,
-					"%s - calling hangup\n", __func__);
-				tty_hangup(tty);
-			}
-			tty_kref_put(tty);
+		if (!acm->clocal && (acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) {
+			dev_dbg(&acm->control->dev, "%s - calling hangup\n",
+					__func__);
+			tty_port_tty_hangup(&acm->port, false);
 		}
 
 		acm->ctrlin = newctrl;
@@ -1498,15 +1492,9 @@ err_out:
 static int acm_reset_resume(struct usb_interface *intf)
 {
 	struct acm *acm = usb_get_intfdata(intf);
-	struct tty_struct *tty;
 
-	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags)) {
-		tty = tty_port_tty_get(&acm->port);
-		if (tty) {
-			tty_hangup(tty);
-			tty_kref_put(tty);
-		}
-	}
+	if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags))
+		tty_port_tty_hangup(&acm->port, false);
 
 	return acm_resume(intf);
 }
diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index 1fd1935c8316..b011478d2e5f 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -378,7 +378,6 @@ 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;
 
@@ -421,12 +420,8 @@ 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 (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);
-	}
+	if (old_dcd_state != p_priv->dcd_state)
+		tty_port_tty_hangup(&port->port, true);
 
 	/* Resubmit urb so we continue receiving */
 	err = usb_submit_urb(urb, GFP_ATOMIC);
@@ -510,7 +505,6 @@ static void	usa28_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;
 	int status = urb->status;
 
@@ -551,12 +545,8 @@ static void	usa28_instat_callback(struct urb *urb)
 	p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
 	p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-	if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
-		tty = tty_port_tty_get(&port->port);
-		if (tty && !C_CLOCAL(tty))
-			tty_hangup(tty);
-		tty_kref_put(tty);
-	}
+	if (old_dcd_state != p_priv->dcd_state && old_dcd_state)
+		tty_port_tty_hangup(&port->port, true);
 
 		/* Resubmit urb so we continue receiving */
 	err = usb_submit_urb(urb, GFP_ATOMIC);
@@ -642,12 +632,8 @@ static void	usa49_instat_callback(struct urb *urb)
 	p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
 	p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-	if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
-		struct tty_struct *tty = tty_port_tty_get(&port->port);
-		if (tty && !C_CLOCAL(tty))
-			tty_hangup(tty);
-		tty_kref_put(tty);
-	}
+	if (old_dcd_state != p_priv->dcd_state && old_dcd_state)
+		tty_port_tty_hangup(&port->port, true);
 
 	/* Resubmit urb so we continue receiving */
 	err = usb_submit_urb(urb, GFP_ATOMIC);
@@ -851,7 +837,6 @@ static void	usa90_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;
 
@@ -880,12 +865,8 @@ static void	usa90_instat_callback(struct urb *urb)
 	p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
 	p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-	if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
-		tty = tty_port_tty_get(&port->port);
-		if (tty && !C_CLOCAL(tty))
-			tty_hangup(tty);
-		tty_kref_put(tty);
-	}
+	if (old_dcd_state != p_priv->dcd_state && old_dcd_state)
+		tty_port_tty_hangup(&port->port, true);
 
 	/* Resubmit urb so we continue receiving */
 	err = usb_submit_urb(urb, GFP_ATOMIC);
@@ -953,12 +934,8 @@ static void	usa67_instat_callback(struct urb *urb)
 	p_priv->cts_state = ((msg->hskia_cts) ? 1 : 0);
 	p_priv->dcd_state = ((msg->gpia_dcd) ? 1 : 0);
 
-	if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
-		struct tty_struct *tty = tty_port_tty_get(&port->port);
-		if (tty && !C_CLOCAL(tty))
-			tty_hangup(tty);
-		tty_kref_put(tty);
-	}
+	if (old_dcd_state != p_priv->dcd_state && old_dcd_state)
+		tty_port_tty_hangup(&port->port, true);
 
 	/* Resubmit urb so we continue receiving */
 	err = usb_submit_urb(urb, GFP_ATOMIC);
diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index f7d339d8187b..602d1f389a3b 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -1532,13 +1532,8 @@ static void option_instat_callback(struct urb *urb)
 			portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
 			portdata->ri_state = ((signals & 0x08) ? 1 : 0);
 
-			if (old_dcd_state && !portdata->dcd_state) {
-				struct tty_struct *tty =
-						tty_port_tty_get(&port->port);
-				if (tty && !C_CLOCAL(tty))
-					tty_hangup(tty);
-				tty_kref_put(tty);
-			}
+			if (old_dcd_state && !portdata->dcd_state)
+				tty_port_tty_hangup(&port->port, true);
 		} else {
 			dev_dbg(dev, "%s: type %x req %x\n", __func__,
 				req_pkt->bRequestType, req_pkt->bRequest);
diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index c13f6e747748..d66148a17fe3 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -628,7 +628,6 @@ static void sierra_instat_callback(struct urb *urb)
 			unsigned char signals = *((unsigned char *)
 					urb->transfer_buffer +
 					sizeof(struct usb_ctrlrequest));
-			struct tty_struct *tty;
 
 			dev_dbg(&port->dev, "%s: signal x%x\n", __func__,
 				signals);
@@ -639,11 +638,8 @@ static void sierra_instat_callback(struct urb *urb)
 			portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
 			portdata->ri_state = ((signals & 0x08) ? 1 : 0);
 
-			tty = tty_port_tty_get(&port->port);
-			if (tty && !C_CLOCAL(tty) &&
-					old_dcd_state && !portdata->dcd_state)
-				tty_hangup(tty);
-			tty_kref_put(tty);
+			if (old_dcd_state && !portdata->dcd_state)
+				tty_port_tty_hangup(&port->port, true);
 		} else {
 			dev_dbg(&port->dev, "%s: type %x req %x\n",
 				__func__, req_pkt->bRequestType,
diff --git a/include/linux/tty.h b/include/linux/tty.h
index b6e890a87eb1..d3548f871968 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -534,6 +534,7 @@ extern int tty_port_carrier_raised(struct tty_port *port);
 extern void tty_port_raise_dtr_rts(struct tty_port *port);
 extern void tty_port_lower_dtr_rts(struct tty_port *port);
 extern void tty_port_hangup(struct tty_port *port);
+extern void tty_port_tty_hangup(struct tty_port *port, bool check_clocal);
 extern void tty_port_tty_wakeup(struct tty_port *port);
 extern int tty_port_block_til_ready(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp);
diff --git a/net/irda/ircomm/ircomm_tty_attach.c b/net/irda/ircomm/ircomm_tty_attach.c
index edab393e0c82..a2a508f5f268 100644
--- a/net/irda/ircomm/ircomm_tty_attach.c
+++ b/net/irda/ircomm/ircomm_tty_attach.c
@@ -997,12 +997,8 @@ static int ircomm_tty_state_ready(struct ircomm_tty_cb *self,
 			self->settings.dce = IRCOMM_DELTA_CD;
 			ircomm_tty_check_modem_status(self);
 		} else {
-			struct tty_struct *tty = tty_port_tty_get(&self->port);
 			IRDA_DEBUG(0, "%s(), hanging up!\n", __func__ );
-			if (tty) {
-				tty_hangup(tty);
-				tty_kref_put(tty);
-			}
+			tty_port_tty_hangup(&self->port, false);
 		}
 		break;
 	default:
-- 
cgit v1.2.3


From 21622939fc452c7fb739464b8e49368c3ceaa0ee Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@hurleysoftware.com>
Date: Mon, 11 Mar 2013 16:44:21 -0400
Subject: tty: Add diagnostic for halted line discipline

Flip buffer work must not be scheduled by the line discipline
after the line discipline has been halted; issue warning.

Note: drivers can still schedule flip buffer work.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/n_tty.c     | 8 ++++++++
 drivers/tty/tty_ldisc.c | 7 ++++++-
 include/linux/tty.h     | 1 +
 3 files changed, 15 insertions(+), 1 deletion(-)

(limited to 'include/linux/tty.h')

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 68865d9af8a0..16793eccc6ae 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -153,6 +153,12 @@ static void n_tty_set_room(struct tty_struct *tty)
 	if (left && !old_left) {
 		WARN_RATELIMIT(tty->port->itty == NULL,
 				"scheduling with invalid itty\n");
+		/* see if ldisc has been killed - if so, this means that
+		 * even though the ldisc has been halted and ->buf.work
+		 * cancelled, ->buf.work is about to be rescheduled
+		 */
+		WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
+			       "scheduling buffer work for halted ldisc\n");
 		schedule_work(&tty->port->buf.work);
 	}
 }
@@ -1624,6 +1630,8 @@ static int n_tty_open(struct tty_struct *tty)
 		goto err_free_bufs;
 
 	tty->disc_data = ldata;
+	/* indicate buffer work may resume */
+	clear_bit(TTY_LDISC_HALTED, &tty->flags);
 	reset_buffer_flags(tty);
 	tty_unthrottle(tty);
 	ldata->column = 0;
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index d794087c327e..c641321b9404 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -375,6 +375,7 @@ static inline void tty_ldisc_put(struct tty_ldisc *ld)
 
 void tty_ldisc_enable(struct tty_struct *tty)
 {
+	clear_bit(TTY_LDISC_HALTED, &tty->flags);
 	set_bit(TTY_LDISC, &tty->flags);
 	clear_bit(TTY_LDISC_CHANGING, &tty->flags);
 	wake_up(&tty_ldisc_wait);
@@ -513,8 +514,11 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
 
 static int tty_ldisc_halt(struct tty_struct *tty)
 {
+	int scheduled;
 	clear_bit(TTY_LDISC, &tty->flags);
-	return cancel_work_sync(&tty->port->buf.work);
+	scheduled = cancel_work_sync(&tty->port->buf.work);
+	set_bit(TTY_LDISC_HALTED, &tty->flags);
+	return scheduled;
 }
 
 /**
@@ -820,6 +824,7 @@ void tty_ldisc_hangup(struct tty_struct *tty)
 	clear_bit(TTY_LDISC, &tty->flags);
 	tty_unlock(tty);
 	cancel_work_sync(&tty->port->buf.work);
+	set_bit(TTY_LDISC_HALTED, &tty->flags);
 	mutex_unlock(&tty->ldisc_mutex);
 retry:
 	tty_lock(tty);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index d3548f871968..66ae020e8a98 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -315,6 +315,7 @@ struct tty_file_private {
 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
 #define TTY_HUPPED 		18	/* Post driver->hangup() */
 #define TTY_HUPPING 		21	/* ->hangup() in progress */
+#define TTY_LDISC_HALTED	22	/* Line discipline is halted */
 
 #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
 
-- 
cgit v1.2.3


From d912156605b0eb3b3070dc7eabc43db6379aa43b Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@hurleysoftware.com>
Date: Mon, 11 Mar 2013 16:44:33 -0400
Subject: tty: Don't reenable already enabled ldisc

tty_ldisc_hangup() guarantees the ldisc is enabled (or that there
is no ldisc). Since __tty_hangup() was the only user, re-define
tty_ldisc_enable() in file-scope.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/tty_io.c    | 1 -
 drivers/tty/tty_ldisc.c | 2 +-
 include/linux/tty.h     | 2 --
 3 files changed, 1 insertion(+), 4 deletions(-)

(limited to 'include/linux/tty.h')

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index d3ddb31e363e..e6ee0f459a20 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -693,7 +693,6 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
 	 */
 	set_bit(TTY_HUPPED, &tty->flags);
 	clear_bit(TTY_HUPPING, &tty->flags);
-	tty_ldisc_enable(tty);
 
 	tty_unlock(tty);
 
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 37671fcc7e4c..9c727da59fac 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -373,7 +373,7 @@ static inline void tty_ldisc_put(struct tty_ldisc *ld)
  *	Clearing directly is allowed.
  */
 
-void tty_ldisc_enable(struct tty_struct *tty)
+static void tty_ldisc_enable(struct tty_struct *tty)
 {
 	clear_bit(TTY_LDISC_HALTED, &tty->flags);
 	set_bit(TTY_LDISC, &tty->flags);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 66ae020e8a98..367a9dfc4ea2 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -561,8 +561,6 @@ extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty);
 extern void tty_ldisc_init(struct tty_struct *tty);
 extern void tty_ldisc_deinit(struct tty_struct *tty);
 extern void tty_ldisc_begin(void);
-/* This last one is just for the tty layer internals and shouldn't be used elsewhere */
-extern void tty_ldisc_enable(struct tty_struct *tty);
 
 
 /* n_tty.c */
-- 
cgit v1.2.3