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, 62 insertions, 113 deletions

diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 2fd449bcfa35..29346d79df7b 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -206,18 +206,18 @@ static void edge_bulk_out_data_callback	(struct urb *urb);
 static void edge_bulk_out_cmd_callback	(struct urb *urb);
 
 /* function prototypes for the usbserial callbacks */
-static int  edge_open			(struct usb_serial_port *port, struct file *filp);
-static void edge_close			(struct usb_serial_port *port, struct file *filp);
-static int  edge_write			(struct usb_serial_port *port, const unsigned char *buf, int count);
-static int  edge_write_room		(struct usb_serial_port *port);
-static int  edge_chars_in_buffer	(struct usb_serial_port *port);
-static void edge_throttle		(struct usb_serial_port *port);
-static void edge_unthrottle		(struct usb_serial_port *port);
-static void edge_set_termios		(struct usb_serial_port *port, struct ktermios *old_termios);
-static int  edge_ioctl			(struct usb_serial_port *port, struct file *file, unsigned int cmd, unsigned long arg);
-static void edge_break			(struct usb_serial_port *port, int break_state);
-static int  edge_tiocmget		(struct usb_serial_port *port, struct file *file);
-static int  edge_tiocmset		(struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear);
+static int  edge_open			(struct tty_struct *tty, struct usb_serial_port *port, struct file *filp);
+static void edge_close			(struct tty_struct *tty, struct usb_serial_port *port, struct file *filp);
+static int  edge_write			(struct tty_struct *tty, struct usb_serial_port *port, const unsigned char *buf, int count);
+static int  edge_write_room		(struct tty_struct *tty);
+static int  edge_chars_in_buffer	(struct tty_struct *tty);
+static void edge_throttle		(struct tty_struct *tty);
+static void edge_unthrottle		(struct tty_struct *tty);
+static void edge_set_termios		(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios);
+static int  edge_ioctl			(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg);
+static void edge_break			(struct tty_struct *tty, int break_state);
+static int  edge_tiocmget		(struct tty_struct *tty, struct file *file);
+static int  edge_tiocmset		(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear);
 static int  edge_startup		(struct usb_serial *serial);
 static void edge_shutdown		(struct usb_serial *serial);
 
@@ -233,7 +233,8 @@ static void handle_new_lsr		(struct edgeport_port *edge_port, __u8 lsrData, __u8
 static int  send_iosp_ext_cmd		(struct edgeport_port *edge_port, __u8 command, __u8 param);
 static int  calc_baud_rate_divisor	(int baud_rate, int *divisor);
 static int  send_cmd_write_baud_rate	(struct edgeport_port *edge_port, int baudRate);
-static void change_port_settings	(struct edgeport_port *edge_port, struct ktermios *old_termios);
+static void change_port_settings	(struct tty_struct *tty, struct edgeport_port *edge_port,
+					 struct ktermios *old_termios);
 static int  send_cmd_write_uart_register	(struct edgeport_port *edge_port, __u8 regNum, __u8 regValue);
 static int  write_cmd_usb		(struct edgeport_port *edge_port, unsigned char *buffer, int writeLength);
 static void send_more_port_data		(struct edgeport_serial *edge_serial, struct edgeport_port *edge_port);
@@ -639,8 +640,8 @@ static void edge_interrupt_callback (struct urb *urb)
 					dbg("%s - txcredits for port%d = %d", __func__, portNumber, edge_port->txCredits);
 
 					/* tell the tty driver that something has changed */
-					if (edge_port->port->tty)
-						tty_wakeup(edge_port->port->tty);
+					if (edge_port->port->port.tty)
+						tty_wakeup(edge_port->port->port.tty);
 
 					// Since we have more credit, check if more data can be sent
 					send_more_port_data(edge_serial, edge_port);
@@ -737,7 +738,7 @@ static void edge_bulk_out_data_callback (struct urb *urb)
 		    __func__, status);
 	}
 
-	tty = edge_port->port->tty;
+	tty = edge_port->port->port.tty;
 
 	if (tty && edge_port->open) {
 		/* let the tty driver wakeup if it has a special write_wakeup function */
@@ -781,7 +782,7 @@ static void edge_bulk_out_cmd_callback (struct urb *urb)
 	}
 
 	/* Get pointer to tty */
-	tty = edge_port->port->tty;
+	tty = edge_port->port->port.tty;
 
 	/* tell the tty driver that something has changed */
 	if (tty && edge_port->open)
@@ -803,7 +804,8 @@ static void edge_bulk_out_cmd_callback (struct urb *urb)
  *	If successful, we return 0
  *	Otherwise we return a negative error number.
  *****************************************************************************/
-static int edge_open (struct usb_serial_port *port, struct file * filp)
+static int edge_open(struct tty_struct *tty,
+			struct usb_serial_port *port, struct file * filp)
 {
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	struct usb_serial *serial;
@@ -815,16 +817,15 @@ static int edge_open (struct usb_serial_port *port, struct file * filp)
 	if (edge_port == NULL)
 		return -ENODEV;
 
-	if (port->tty)
-		port->tty->low_latency = low_latency;
+	if (tty)
+		tty->low_latency = low_latency;
 
 	/* see if we've set up our endpoint info yet (can't set it up in edge_startup
 	   as the structures were not set up at that time.) */
 	serial = port->serial;
 	edge_serial = usb_get_serial_data(serial);
-	if (edge_serial == NULL) {
+	if (edge_serial == NULL)
 		return -ENODEV;
-	}
 	if (edge_serial->interrupt_in_buffer == NULL) {
 		struct usb_serial_port *port0 = serial->port[0];
 		
@@ -908,7 +909,7 @@ static int edge_open (struct usb_serial_port *port, struct file * filp)
 
 	if (!edge_port->txfifo.fifo) {
 		dbg("%s - no memory", __func__);
-		edge_close (port, filp);
+		edge_close (tty, port, filp);
 		return -ENOMEM;
 	}
 
@@ -918,7 +919,7 @@ static int edge_open (struct usb_serial_port *port, struct file * filp)
 
 	if (!edge_port->write_urb) {
 		dbg("%s - no memory", __func__);
-		edge_close (port, filp);
+		edge_close (tty, port, filp);
 		return -ENOMEM;
 	}
 
@@ -1038,7 +1039,8 @@ static void block_until_tx_empty (struct edgeport_port *edge_port)
  * edge_close
  *	this function is called by the tty driver when a port is closed
  *****************************************************************************/
-static void edge_close (struct usb_serial_port *port, struct file * filp)
+static void edge_close(struct tty_struct *tty,
+			struct usb_serial_port *port, struct file * filp)
 {
 	struct edgeport_serial *edge_serial;
 	struct edgeport_port *edge_port;
@@ -1106,7 +1108,8 @@ static void edge_close (struct usb_serial_port *port, struct file * filp)
  *	If successful, we return the number of bytes written, otherwise we return
  *	a negative error number.
  *****************************************************************************/
-static int edge_write (struct usb_serial_port *port, const unsigned char *data, int count)
+static int edge_write(struct tty_struct *tty, struct usb_serial_port *port,
+					const unsigned char *data, int count)
 {
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	struct TxFifo *fifo;
@@ -1308,8 +1311,9 @@ exit_send:
  *	(the txCredits), 
  *	Otherwise we return a negative error number.
  *****************************************************************************/
-static int edge_write_room (struct usb_serial_port *port)
+static int edge_write_room(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	int room;
 	unsigned long flags;
@@ -1347,8 +1351,9 @@ static int edge_write_room (struct usb_serial_port *port)
  *	system, 
  *	Otherwise we return a negative error number.
  *****************************************************************************/
-static int edge_chars_in_buffer (struct usb_serial_port *port)
+static int edge_chars_in_buffer(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	int num_chars;
 	unsigned long flags;
@@ -1381,10 +1386,10 @@ static int edge_chars_in_buffer (struct usb_serial_port *port)
  *	this function is called by the tty driver when it wants to stop the data
  *	being read from the port.
  *****************************************************************************/
-static void edge_throttle (struct usb_serial_port *port)
+static void edge_throttle(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
-	struct tty_struct *tty;
 	int status;
 
 	dbg("%s - port %d", __func__, port->number);
@@ -1397,16 +1402,10 @@ static void edge_throttle (struct usb_serial_port *port)
 		return;
 	}
 
-	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 = edge_write (port, &stop_char, 1);
+		status = edge_write (tty, port, &stop_char, 1);
 		if (status <= 0) {
 			return;
 		}
@@ -1430,10 +1429,10 @@ static void edge_throttle (struct usb_serial_port *port)
  *	this function is called by the tty driver when it wants to resume the data
  *	being read from the port (called after SerialThrottle is called)
  *****************************************************************************/
-static void edge_unthrottle (struct usb_serial_port *port)
+static void edge_unthrottle(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
-	struct tty_struct *tty;
 	int status;
 
 	dbg("%s - port %d", __func__, port->number);
@@ -1446,31 +1445,18 @@ static void edge_unthrottle (struct usb_serial_port *port)
 		return;
 	}
 
-	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 = edge_write (port, &start_char, 1);
-		if (status <= 0) {
+		status = edge_write(tty, port, &start_char, 1);
+		if (status <= 0)
 			return;
-		}
 	}
-
 	/* if we are implementing RTS/CTS, toggle that line */
 	if (tty->termios->c_cflag & CRTSCTS) {
 		edge_port->shadowMCR |= MCR_RTS;
-		status = send_cmd_write_uart_register(edge_port, MCR, edge_port->shadowMCR);
-		if (status != 0) {
-			return;
-		}
+		send_cmd_write_uart_register(edge_port, MCR, edge_port->shadowMCR);
 	}
-
-	return;
 }
 
 
@@ -1478,11 +1464,10 @@ static void edge_unthrottle (struct usb_serial_port *port)
  * SerialSetTermios
  *	this function is called by the tty driver when it wants to change the termios structure
  *****************************************************************************/
-static void edge_set_termios (struct usb_serial_port *port, struct ktermios *old_termios)
+static void edge_set_termios(struct tty_struct *tty,
+	struct usb_serial_port *port, struct ktermios *old_termios)
 {
-	/* FIXME: This function appears unused ?? */
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
-	struct tty_struct *tty = port->tty;
 	unsigned int cflag;
 
 	cflag = tty->termios->c_cflag;
@@ -1502,9 +1487,7 @@ static void edge_set_termios (struct usb_serial_port *port, struct ktermios *old
 	}
 
 	/* change the port settings to the new ones specified */
-	change_port_settings (edge_port, old_termios);
-
-	return;
+	change_port_settings(tty, edge_port, old_termios);
 }
 
 
@@ -1536,25 +1519,9 @@ static int get_lsr_info(struct edgeport_port *edge_port, unsigned int __user *va
 	return 0;
 }
 
-static int get_number_bytes_avail(struct edgeport_port *edge_port, unsigned int __user *value)
-{
-	unsigned int result = 0;
-	struct tty_struct *tty = edge_port->port->tty;
-
-	if (!tty)
-		return -ENOIOCTLCMD;
-
-	result = tty->read_cnt;
-
-	dbg("%s(%d) = %d", __func__,  edge_port->port->number, result);
-	if (copy_to_user(value, &result, sizeof(int)))
-		return -EFAULT;
-	//return 0;
-	return -ENOIOCTLCMD;
-}
-
-static int edge_tiocmset (struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear)
+static int edge_tiocmset(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	unsigned int mcr;
 
@@ -1582,8 +1549,9 @@ static int edge_tiocmset (struct usb_serial_port *port, struct file *file, unsig
 	return 0;
 }
 
-static int edge_tiocmget(struct usb_serial_port *port, struct file *file)
+static int edge_tiocmget(struct tty_struct *tty, struct file *file)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	unsigned int result = 0;
 	unsigned int msr;
@@ -1624,9 +1592,6 @@ static int get_serial_info(struct edgeport_port *edge_port, struct serial_struct
 	tmp.baud_base		= 9600;
 	tmp.close_delay		= 5*HZ;
 	tmp.closing_wait	= 30*HZ;
-//	tmp.custom_divisor	= state->custom_divisor;
-//	tmp.hub6		= state->hub6;
-//	tmp.io_type		= state->io_type;
 
 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
 		return -EFAULT;
@@ -1639,8 +1604,10 @@ static int get_serial_info(struct edgeport_port *edge_port, struct serial_struct
  * SerialIoctl
  *	this function handles any ioctl calls to the driver
  *****************************************************************************/
-static int edge_ioctl (struct usb_serial_port *port, struct file *file, unsigned int cmd, unsigned long arg)
+static int edge_ioctl(struct tty_struct *tty, struct file *file,
+					unsigned int cmd, unsigned long arg)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	DEFINE_WAIT(wait);
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	struct async_icount cnow;
@@ -1650,25 +1617,14 @@ static int edge_ioctl (struct usb_serial_port *port, struct file *file, unsigned
 	dbg("%s - port %d, cmd = 0x%x", __func__, port->number, cmd);
 
 	switch (cmd) {
-		// return number of bytes available
-		case TIOCINQ:
-			dbg("%s (%d) TIOCINQ", __func__,  port->number);
-			return get_number_bytes_avail(edge_port, (unsigned int __user *) arg);
-			break;
-
 		case TIOCSERGETLSR:
 			dbg("%s (%d) TIOCSERGETLSR", __func__,  port->number);
 			return get_lsr_info(edge_port, (unsigned int __user *) arg);
-			return 0;
 
 		case TIOCGSERIAL:
 			dbg("%s (%d) TIOCGSERIAL", __func__,  port->number);
 			return get_serial_info(edge_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 = edge_port->icount;
@@ -1723,8 +1679,9 @@ static int edge_ioctl (struct usb_serial_port *port, struct file *file, unsigned
  * SerialBreak
  *	this function sends a break to the port
  *****************************************************************************/
-static void edge_break (struct usb_serial_port *port, int break_state)
+static void edge_break (struct tty_struct *tty, int break_state)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	struct edgeport_serial *edge_serial = usb_get_serial_data(port->serial);
 	int status;
@@ -1866,7 +1823,7 @@ static void process_rcvd_data (struct edgeport_serial *edge_serial, unsigned cha
 					port = edge_serial->serial->port[edge_serial->rxPort];
 					edge_port = usb_get_serial_port_data(port);
 					if (edge_port->open) {
-						tty = edge_port->port->tty;
+						tty = edge_port->port->port.tty;
 						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);
@@ -1941,8 +1898,9 @@ static void process_rcvd_status (struct edgeport_serial *edge_serial, __u8 byte2
 		handle_new_msr (edge_port, byte2);
 
 		/* send the current line settings to the port so we are in sync with any further termios calls */
-		if (edge_port->port->tty)
-			change_port_settings (edge_port, edge_port->port->tty->termios);
+		/* 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);
 
 		/* we have completed the open */
 		edge_port->openPending = false;
@@ -2078,8 +2036,8 @@ static void handle_new_lsr(struct edgeport_port *edge_port, __u8 lsrData, __u8 l
 	}
 
 	/* Place LSR data byte into Rx buffer */
-	if (lsrData && edge_port->port->tty)
-		edge_tty_recv(&edge_port->port->dev, edge_port->port->tty, &data, 1);
+	if (lsrData && edge_port->port->port.tty)
+		edge_tty_recv(&edge_port->port->dev, edge_port->port->port.tty, &data, 1);
 
 	/* update input line counters */
 	icount = &edge_port->icount;
@@ -2473,13 +2431,11 @@ static int send_cmd_write_uart_register (struct edgeport_port *edge_port, __u8 r
  *	This routine is called to set the UART on the device to match the specified
  *	new settings.
  *****************************************************************************/
-#ifndef CMSPAR
-#define CMSPAR 0
-#endif
-static void change_port_settings (struct edgeport_port *edge_port, struct ktermios *old_termios)
+
+static void change_port_settings(struct tty_struct *tty,
+	struct edgeport_port *edge_port, struct ktermios *old_termios)
 {
 	struct edgeport_serial *edge_serial = usb_get_serial_data(edge_port->port->serial);
-	struct tty_struct *tty;
 	int baud;
 	unsigned cflag;
 	__u8 mask = 0xff;
@@ -2498,13 +2454,6 @@ static void change_port_settings (struct edgeport_port *edge_port, struct ktermi
 		return;
 	}
 
-	tty = edge_port->port->tty;
-	if ((!tty) ||
-	    (!tty->termios)) {
-		dbg("%s - no tty structures", __func__);
-		return;
-	}
-
 	cflag = tty->termios->c_cflag;
 
 	switch (cflag & CSIZE) {