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, 40 insertions, 65 deletions

diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 1e936a1cbe0..4350990abf1 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -43,29 +43,23 @@
 #include <linux/usb/serial.h>
 
 /* Function prototypes */
-static int  option_open(struct usb_serial_port *port, struct file *filp);
-static void option_close(struct usb_serial_port *port, struct file *filp);
+static int  option_open(struct tty_struct *tty, struct usb_serial_port *port, struct file *filp);
+static void option_close(struct tty_struct *tty, struct usb_serial_port *port, struct file *filp);
 static int  option_startup(struct usb_serial *serial);
 static void option_shutdown(struct usb_serial *serial);
-static void option_rx_throttle(struct usb_serial_port *port);
-static void option_rx_unthrottle(struct usb_serial_port *port);
-static int  option_write_room(struct usb_serial_port *port);
+static int  option_write_room(struct tty_struct *tty);
 
 static void option_instat_callback(struct urb *urb);
 
-static int option_write(struct usb_serial_port *port,
+static int option_write(struct tty_struct *tty, struct usb_serial_port *port,
 			const unsigned char *buf, int count);
-
-static int  option_chars_in_buffer(struct usb_serial_port *port);
-static int  option_ioctl(struct usb_serial_port *port, struct file *file,
-			unsigned int cmd, unsigned long arg);
-static void option_set_termios(struct usb_serial_port *port,
-				struct ktermios *old);
-static void option_break_ctl(struct usb_serial_port *port, int break_state);
-static int  option_tiocmget(struct usb_serial_port *port, struct file *file);
-static int  option_tiocmset(struct usb_serial_port *port, struct file *file,
+static int  option_chars_in_buffer(struct tty_struct *tty);
+static void option_set_termios(struct tty_struct *tty,
+			struct usb_serial_port *port, struct ktermios *old);
+static int  option_tiocmget(struct tty_struct *tty, struct file *file);
+static int  option_tiocmset(struct tty_struct *tty, struct file *file,
 				unsigned int set, unsigned int clear);
-static int  option_send_setup(struct usb_serial_port *port);
+static int  option_send_setup(struct tty_struct *tty, struct usb_serial_port *port);
 
 /* Vendor and product IDs */
 #define OPTION_VENDOR_ID			0x0AF0
@@ -342,11 +336,7 @@ static struct usb_serial_driver option_1port_device = {
 	.write             = option_write,
 	.write_room        = option_write_room,
 	.chars_in_buffer   = option_chars_in_buffer,
-	.throttle          = option_rx_throttle,
-	.unthrottle        = option_rx_unthrottle,
-	.ioctl             = option_ioctl,
 	.set_termios       = option_set_termios,
-	.break_ctl         = option_break_ctl,
 	.tiocmget          = option_tiocmget,
 	.tiocmset          = option_tiocmset,
 	.attach            = option_startup,
@@ -417,33 +407,18 @@ static void __exit option_exit(void)
 module_init(option_init);
 module_exit(option_exit);
 
-static void option_rx_throttle(struct usb_serial_port *port)
-{
-	dbg("%s", __func__);
-}
-
-static void option_rx_unthrottle(struct usb_serial_port *port)
-{
-	dbg("%s", __func__);
-}
-
-static void option_break_ctl(struct usb_serial_port *port, int break_state)
-{
-	/* Unfortunately, I don't know how to send a break */
-	dbg("%s", __func__);
-}
-
-static void option_set_termios(struct usb_serial_port *port,
-			struct ktermios *old_termios)
+static void option_set_termios(struct tty_struct *tty,
+		struct usb_serial_port *port, struct ktermios *old_termios)
 {
 	dbg("%s", __func__);
 	/* Doesn't support option setting */
-	tty_termios_copy_hw(port->tty->termios, old_termios);
-	option_send_setup(port);
+	tty_termios_copy_hw(tty->termios, old_termios);
+	option_send_setup(tty, port);
 }
 
-static int option_tiocmget(struct usb_serial_port *port, struct file *file)
+static int option_tiocmget(struct tty_struct *tty, struct file *file)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	unsigned int value;
 	struct option_port_private *portdata;
 
@@ -459,9 +434,10 @@ static int option_tiocmget(struct usb_serial_port *port, struct file *file)
 	return value;
 }
 
-static int option_tiocmset(struct usb_serial_port *port, struct file *file,
+static int option_tiocmset(struct tty_struct *tty, struct file *file,
 			unsigned int set, unsigned int clear)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct option_port_private *portdata;
 
 	portdata = usb_get_serial_port_data(port);
@@ -476,17 +452,11 @@ static int option_tiocmset(struct usb_serial_port *port, struct file *file,
 		portdata->rts_state = 0;
 	if (clear & TIOCM_DTR)
 		portdata->dtr_state = 0;
-	return option_send_setup(port);
-}
-
-static int option_ioctl(struct usb_serial_port *port, struct file *file,
-			unsigned int cmd, unsigned long arg)
-{
-	return -ENOIOCTLCMD;
+	return option_send_setup(tty, port);
 }
 
 /* Write */
-static int option_write(struct usb_serial_port *port,
+static int option_write(struct tty_struct *tty, struct usb_serial_port *port,
 			const unsigned char *buf, int count)
 {
 	struct option_port_private *portdata;
@@ -562,7 +532,7 @@ static void option_indat_callback(struct urb *urb)
 		dbg("%s: nonzero status: %d on endpoint %02x.",
 		    __func__, status, endpoint);
 	} else {
-		tty = port->tty;
+		tty = port->port.tty;
 		if (urb->actual_length) {
 			tty_buffer_request_room(tty, urb->actual_length);
 			tty_insert_flip_string(tty, data, urb->actual_length);
@@ -572,7 +542,7 @@ static void option_indat_callback(struct urb *urb)
 		}
 
 		/* Resubmit urb so we continue receiving */
-		if (port->open_count && status != -ESHUTDOWN) {
+		if (port->port.count && status != -ESHUTDOWN) {
 			err = usb_submit_urb(urb, GFP_ATOMIC);
 			if (err)
 				printk(KERN_ERR "%s: resubmit read urb failed. "
@@ -638,9 +608,9 @@ static void option_instat_callback(struct urb *urb)
 			portdata->dsr_state = ((signals & 0x02) ? 1 : 0);
 			portdata->ri_state = ((signals & 0x08) ? 1 : 0);
 
-			if (port->tty && !C_CLOCAL(port->tty) &&
+			if (port->port.tty && !C_CLOCAL(port->port.tty) &&
 					old_dcd_state && !portdata->dcd_state)
-				tty_hangup(port->tty);
+				tty_hangup(port->port.tty);
 		} else {
 			dbg("%s: type %x req %x", __func__,
 				req_pkt->bRequestType,req_pkt->bRequest);
@@ -658,8 +628,9 @@ static void option_instat_callback(struct urb *urb)
 	}
 }
 
-static int option_write_room(struct usb_serial_port *port)
+static int option_write_room(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct option_port_private *portdata;
 	int i;
 	int data_len = 0;
@@ -678,8 +649,9 @@ static int option_write_room(struct usb_serial_port *port)
 	return data_len;
 }
 
-static int option_chars_in_buffer(struct usb_serial_port *port)
+static int option_chars_in_buffer(struct tty_struct *tty)
 {
+	struct usb_serial_port *port = tty->driver_data;
 	struct option_port_private *portdata;
 	int i;
 	int data_len = 0;
@@ -698,7 +670,8 @@ static int option_chars_in_buffer(struct usb_serial_port *port)
 	return data_len;
 }
 
-static int option_open(struct usb_serial_port *port, struct file *filp)
+static int option_open(struct tty_struct *tty,
+			struct usb_serial_port *port, struct file *filp)
 {
 	struct option_port_private *portdata;
 	struct usb_serial *serial = port->serial;
@@ -748,14 +721,16 @@ static int option_open(struct usb_serial_port *port, struct file *filp)
 				usb_pipeout(urb->pipe), 0); */
 	}
 
-	port->tty->low_latency = 1;
+	if (tty)
+		tty->low_latency = 1;
 
-	option_send_setup(port);
+	option_send_setup(tty, port);
 
 	return (0);
 }
 
-static void option_close(struct usb_serial_port *port, struct file *filp)
+static void option_close(struct tty_struct *tty,
+			struct usb_serial_port *port, struct file *filp)
 {
 	int i;
 	struct usb_serial *serial = port->serial;
@@ -770,7 +745,7 @@ static void option_close(struct usb_serial_port *port, struct file *filp)
 	if (serial->dev) {
 		mutex_lock(&serial->disc_mutex);
 		if (!serial->disconnected)
-			option_send_setup(port);
+			option_send_setup(tty, port);
 		mutex_unlock(&serial->disc_mutex);
 
 		/* Stop reading/writing urbs */
@@ -779,7 +754,7 @@ static void option_close(struct usb_serial_port *port, struct file *filp)
 		for (i = 0; i < N_OUT_URB; i++)
 			usb_kill_urb(portdata->out_urbs[i]);
 	}
-	port->tty = NULL;
+	port->port.tty = NULL;	/* FIXME */
 }
 
 /* Helper functions used by option_setup_urbs */
@@ -841,7 +816,8 @@ static void option_setup_urbs(struct usb_serial *serial)
  * This is exactly the same as SET_CONTROL_LINE_STATE from the PSTN
  * CDC.
 */
-static int option_send_setup(struct usb_serial_port *port)
+static int option_send_setup(struct tty_struct *tty,
+						struct usb_serial_port *port)
 {
 	struct usb_serial *serial = port->serial;
 	struct option_port_private *portdata;
@@ -850,7 +826,7 @@ static int option_send_setup(struct usb_serial_port *port)
 
 	portdata = usb_get_serial_port_data(port);
 
-	if (port->tty) {
+	if (tty) {
 		int val = 0;
 		if (portdata->dtr_state)
 			val |= 0x01;
@@ -861,7 +837,6 @@ static int option_send_setup(struct usb_serial_port *port)
 				usb_rcvctrlpipe(serial->dev, 0),
 				0x22,0x21,val,ifNum,NULL,0,USB_CTRL_SET_TIMEOUT);
 	}
-
 	return 0;
 }