usb_serial: API all change

USB serial likes to use port->tty back pointers for the real work it does and
to do so without any actual locking. Unfortunately when you consider hangup
events, hangup/parallel reopen or even worse hangup followed by parallel close
events the tty->port and port->tty pointers are not guaranteed to be the same
as port->tty is the active tty while tty->port is the port the tty may or
may not still be attached to.

So rework the entire API to pass the tty struct. For console cases we need
to pass both for now. This shows up multiple drivers that immediately crash
with USB console some of which have been fixed in the process.

Longer term we need a proper tty as console abstraction

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 35 insertions, 52 deletions

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 50f1fe2..d47f081 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -218,7 +218,7 @@ static void mos7720_bulk_in_callback(struct urb *urb)
 
 	data = urb->transfer_buffer;
 
-	tty = port->tty;
+	tty = port->port.tty;
 	if (tty && urb->actual_length) {
 		tty_buffer_request_room(tty, urb->actual_length);
 		tty_insert_flip_string(tty, data, urb->actual_length);
@@ -264,7 +264,7 @@ static void mos7720_bulk_out_data_callback(struct urb *urb)
 
 	dbg("Entering .........");
 
-	tty = mos7720_port->port->tty;
+	tty = mos7720_port->port->port.tty;
 
 	if (tty && mos7720_port->open)
 		tty_wakeup(tty);
@@ -320,7 +320,8 @@ static int send_mos_cmd(struct usb_serial *serial, __u8 request, __u16 value,
 	return status;
 }
 
-static int mos7720_open(struct usb_serial_port *port, struct file * filp)
+static int mos7720_open(struct tty_struct *tty,
+			struct usb_serial_port *port, struct file * filp)
 {
 	struct usb_serial *serial;
 	struct usb_serial_port *port0;
@@ -443,14 +444,12 @@ static int mos7720_open(struct usb_serial_port *port, struct file * filp)
 	data = 0x0c;
 	send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
 
-//Matrix
-
 	/* force low_latency on so that our tty_push actually forces *
 	 * the data through,otherwise it is scheduled, and with      *
 	 * high data rates (like with OHCI) data can get lost.       */
 
-	if (port->tty)
-		port->tty->low_latency = 1;
+	if (tty)
+		tty->low_latency = 1;
 
 	/* see if we've set up our endpoint info yet   *
 	 * (can't set it up in mos7720_startup as the  *
@@ -515,8 +514,9 @@ static int mos7720_open(struct usb_serial_port *port, struct file * filp)
  *	system,
  *	Otherwise we return a negative error number.
  */
-static int mos7720_chars_in_buffer(struct usb_serial_port *port)
+static int mos7720_chars_in_buffer(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	int i;
 	int chars = 0;
 	struct moschip_port *mos7720_port;
@@ -537,7 +537,8 @@ static int mos7720_chars_in_buffer(struct usb_serial_port *port)
 	return chars;
 }
 
-static void mos7720_close(struct usb_serial_port *port, struct file *filp)
+static void mos7720_close(struct tty_struct *tty,
+			struct usb_serial_port *port, struct file *filp)
 {
 	struct usb_serial *serial;
 	struct moschip_port *mos7720_port;
@@ -588,8 +589,9 @@ static void mos7720_close(struct usb_serial_port *port, struct file *filp)
 	dbg("Leaving %s", __func__);
 }
 
-static void mos7720_break(struct usb_serial_port *port, int break_state)
+static void mos7720_break(struct tty_struct *tty, int break_state)
 {
+	struct usb_serial_port *port = tty->driver_data;
         unsigned char data;
 	struct usb_serial *serial;
 	struct moschip_port *mos7720_port;
@@ -621,8 +623,9 @@ static void mos7720_break(struct usb_serial_port *port, int break_state)
  *	If successful, we return the amount of room that we have for this port
  *	Otherwise we return a negative error number.
  */
-static int mos7720_write_room(struct usb_serial_port *port)
+static int mos7720_write_room(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct moschip_port *mos7720_port;
 	int room = 0;
 	int i;
@@ -645,8 +648,8 @@ static int mos7720_write_room(struct usb_serial_port *port)
 	return room;
 }
 
-static int mos7720_write(struct usb_serial_port *port,
-			 const unsigned char *data, int count)
+static int mos7720_write(struct tty_struct *tty, struct usb_serial_port *port,
+				 const unsigned char *data, int count)
 {
 	int status;
 	int i;
@@ -719,10 +722,10 @@ exit:
 	return bytes_sent;
 }
 
-static void mos7720_throttle(struct usb_serial_port *port)
+static void mos7720_throttle(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct moschip_port *mos7720_port;
-	struct tty_struct *tty;
 	int status;
 
 	dbg("%s- port %d\n", __func__, port->number);
@@ -739,16 +742,10 @@ static void mos7720_throttle(struct usb_serial_port *port)
 
 	dbg("%s: Entering ..........", __func__);
 
-	tty = port->tty;
-	if (!tty) {
-		dbg("%s - no tty available", __func__);
-		return;
-	}
-
 	/* if we are implementing XON/XOFF, send the stop character */
 	if (I_IXOFF(tty)) {
 		unsigned char stop_char = STOP_CHAR(tty);
-		status = mos7720_write(port, &stop_char, 1);
+		status = mos7720_write(tty, port, &stop_char, 1);
 		if (status <= 0)
 			return;
 	}
@@ -764,11 +761,11 @@ static void mos7720_throttle(struct usb_serial_port *port)
 	}
 }
 
-static void mos7720_unthrottle(struct usb_serial_port *port)
+static void mos7720_unthrottle(struct tty_struct *tty)
 {
-	struct tty_struct *tty;
-	int status;
+	struct usb_serial_port *port = tty->driver_data;
 	struct moschip_port *mos7720_port = usb_get_serial_port_data(port);
+	int status;
 
 	if (mos7720_port == NULL)
 		return;
@@ -780,16 +777,10 @@ static void mos7720_unthrottle(struct usb_serial_port *port)
 
 	dbg("%s: Entering ..........", __func__);
 
-	tty = port->tty;
-	if (!tty) {
-		dbg("%s - no tty available", __func__);
-		return;
-	}
-
 	/* if we are implementing XON/XOFF, send the start character */
 	if (I_IXOFF(tty)) {
 		unsigned char start_char = START_CHAR(tty);
-		status = mos7720_write(port, &start_char, 1);
+		status = mos7720_write(tty, port, &start_char, 1);
 		if (status <= 0)
 			return;
 	}
@@ -1011,12 +1002,12 @@ static int send_cmd_write_baud_rate(struct moschip_port *mos7720_port,
  *	This routine is called to set the UART on the device to match
  *      the specified new settings.
  */
-static void change_port_settings(struct moschip_port *mos7720_port,
+static void change_port_settings(struct tty_struct *tty,
+				 struct moschip_port *mos7720_port,
 				 struct ktermios *old_termios)
 {
 	struct usb_serial_port *port;
 	struct usb_serial *serial;
-	struct tty_struct *tty;
 	int baud;
 	unsigned cflag;
 	unsigned iflag;
@@ -1042,8 +1033,6 @@ static void change_port_settings(struct moschip_port *mos7720_port,
 		return;
 	}
 
-	tty = mos7720_port->port->tty;
-
 	dbg("%s: Entering ..........", __func__);
 
 	lData = UART_LCR_WLEN8;
@@ -1198,14 +1187,13 @@ static void change_port_settings(struct moschip_port *mos7720_port,
  *	this function is called by the tty driver when it wants to change the
  *	termios structure.
  */
-static void mos7720_set_termios(struct usb_serial_port *port,
-				struct ktermios *old_termios)
+static void mos7720_set_termios(struct tty_struct *tty,
+		struct usb_serial_port *port, struct ktermios *old_termios)
 {
 	int status;
 	unsigned int cflag;
 	struct usb_serial *serial;
 	struct moschip_port *mos7720_port;
-	struct tty_struct *tty;
 
 	serial = port->serial;
 
@@ -1214,9 +1202,6 @@ static void mos7720_set_termios(struct usb_serial_port *port,
 	if (mos7720_port == NULL)
 		return;
 
-	tty = port->tty;
-
-
 	if (!mos7720_port->open) {
 		dbg("%s - port not opened", __func__);
 		return;
@@ -1237,7 +1222,7 @@ static void mos7720_set_termios(struct usb_serial_port *port,
 	dbg("%s - port %d", __func__, port->number);
 
 	/* change the port settings to the new ones specified */
-	change_port_settings(mos7720_port, old_termios);
+	change_port_settings(tty, mos7720_port, old_termios);
 
 	if(!port->read_urb) {
 		dbg("%s","URB KILLED !!!!!\n");
@@ -1264,13 +1249,13 @@ static void mos7720_set_termios(struct usb_serial_port *port,
  * 	    transmit holding register is empty.  This functionality
  * 	    allows an RS485 driver to be written in user space.
  */
-static int get_lsr_info(struct moschip_port *mos7720_port,
+static int get_lsr_info(struct tty_struct *tty, struct moschip_port *mos7720_port,
 			unsigned int __user *value)
 {
 	int count;
 	unsigned int result = 0;
 
-	count = mos7720_chars_in_buffer(mos7720_port->port);
+	count = mos7720_chars_in_buffer(tty);
 	if (count == 0) {
 		dbg("%s -- Empty", __func__);
 		result = TIOCSER_TEMT;
@@ -1290,7 +1275,7 @@ static int get_number_bytes_avail(struct moschip_port *mos7720_port,
 				  unsigned int __user *value)
 {
 	unsigned int result = 0;
-	struct tty_struct *tty = mos7720_port->port->tty;
+	struct tty_struct *tty = mos7720_port->port->port.tty;
 
 	if (!tty)
 		return -ENOIOCTLCMD;
@@ -1407,9 +1392,10 @@ static int get_serial_info(struct moschip_port *mos7720_port,
 	return 0;
 }
 
-static int mos7720_ioctl(struct usb_serial_port *port, struct file *file,
+static int mos7720_ioctl(struct tty_struct *tty, struct file *file,
 			 unsigned int cmd, unsigned long arg)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct moschip_port *mos7720_port;
 	struct async_icount cnow;
 	struct async_icount cprev;
@@ -1431,9 +1417,10 @@ static int mos7720_ioctl(struct usb_serial_port *port, struct file *file,
 
 	case TIOCSERGETLSR:
 		dbg("%s (%d) TIOCSERGETLSR", __func__,  port->number);
-		return get_lsr_info(mos7720_port, (unsigned int __user *)arg);
+		return get_lsr_info(tty, mos7720_port, (unsigned int __user *)arg);
 		return 0;
 
+	/* FIXME: These should be using the mode methods */
 	case TIOCMBIS:
 	case TIOCMBIC:
 	case TIOCMSET:
@@ -1452,10 +1439,6 @@ static int mos7720_ioctl(struct usb_serial_port *port, struct file *file,
 		return get_serial_info(mos7720_port,
 				       (struct serial_struct __user *)arg);
 
-	case TIOCSSERIAL:
-		dbg("%s (%d) TIOCSSERIAL", __func__,  port->number);
-		break;
-
 	case TIOCMIWAIT:
 		dbg("%s (%d) TIOCMIWAIT", __func__,  port->number);
 		cprev = mos7720_port->icount;