USB: make sure usb serial drivers don't flush to logically disconnected devices

If disconnect() is called for a logical disconnect, no more IO must be
done after disconnect() returns, or the old and new drivers may conflict.
This patch avoids this by using the flag and lock introduced by the earlier
patch for the mos7720 driver.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/mct_u232.c

@@ -487,21 +487,22 @@ error:
 static void mct_u232_close (struct usb_serial_port *port, struct file *filp)
 {
 	unsigned int c_cflag;
-	unsigned long flags;
 	unsigned int control_state;
 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
 	dbg("%s port %d", __FUNCTION__, port->number);
 
    	if (port->tty) {
 		c_cflag = port->tty->termios->c_cflag;
-		if (c_cflag & HUPCL) {
-		   /* drop DTR and RTS */
-		   spin_lock_irqsave(&priv->lock, flags);
-		   priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
-		   control_state = priv->control_state;
-		   spin_unlock_irqrestore(&priv->lock, flags);
-		   mct_u232_set_modem_ctrl(port->serial, control_state);
+		mutex_lock(&port->serial->disc_mutex);
+		if (c_cflag & HUPCL && !port->serial->disconnected) {
+			/* drop DTR and RTS */
+			spin_lock_irq(&priv->lock);
+			priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
+			control_state = priv->control_state;
+			spin_unlock_irq(&priv->lock);
+			mct_u232_set_modem_ctrl(port->serial, control_state);
 		}
+		mutex_unlock(&port->serial->disc_mutex);
 	}
 
 

drivers/usb/serial/option.c

@@ -641,7 +641,10 @@ static void option_close(struct usb_serial_port *port, struct file *filp)
 	portdata->dtr_state = 0;
 
 	if (serial->dev) {
-		option_send_setup(port);
+		mutex_lock(&serial->disc_mutex);
+		if (!serial->disconnected)
+			option_send_setup(port);
+		mutex_unlock(&serial->disc_mutex);
 
 		/* Stop reading/writing urbs */
 		for (i = 0; i < N_IN_URB; i++)

drivers/usb/serial/sierra.c

@@ -597,7 +597,10 @@ static void sierra_close(struct usb_serial_port *port, struct file *filp)
 	portdata->dtr_state = 0;
 
 	if (serial->dev) {
-		sierra_send_setup(port);
+		mutex_lock(&serial->disc_mutex);
+		if (!serial->disconnected)
+			sierra_send_setup(port);
+		mutex_unlock(&serial->disc_mutex);
 
 		/* Stop reading/writing urbs */
 		for (i = 0; i < N_IN_URB; i++)

drivers/usb/serial/visor.c

@@ -349,16 +349,20 @@ static void visor_close (struct usb_serial_port *port, struct file * filp)
 	usb_kill_urb(port->read_urb);
 	usb_kill_urb(port->interrupt_in_urb);
 
-	/* Try to send shutdown message, if the device is gone, this will just fail. */
-	transfer_buffer =  kmalloc (0x12, GFP_KERNEL);
-	if (transfer_buffer) {
-		usb_control_msg (port->serial->dev,
-				 usb_rcvctrlpipe(port->serial->dev, 0),
-				 VISOR_CLOSE_NOTIFICATION, 0xc2,
-				 0x0000, 0x0000, 
-				 transfer_buffer, 0x12, 300);
-		kfree (transfer_buffer);
+	mutex_lock(&port->serial->disc_mutex);
+	if (!port->serial->disconnected) {
+		/* Try to send shutdown message, unless the device is gone */
+		transfer_buffer =  kmalloc (0x12, GFP_KERNEL);
+		if (transfer_buffer) {
+			usb_control_msg (port->serial->dev,
+					 usb_rcvctrlpipe(port->serial->dev, 0),
+					 VISOR_CLOSE_NOTIFICATION, 0xc2,
+					 0x0000, 0x0000,
+					 transfer_buffer, 0x12, 300);
+			kfree (transfer_buffer);
+		}
 	}
+	mutex_lock(&port->serial->disc_mutex);
 
 	if (stats)
 		dev_info(&port->dev, "Bytes In = %d  Bytes Out = %d\n",

drivers/usb/serial/whiteheat.c

@@ -658,11 +658,14 @@ static void whiteheat_close(struct usb_serial_port *port, struct file * filp)
 	struct list_head *tmp2;
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
-	
+
+	mutex_lock(&port->serial->disc_mutex);
 	/* filp is NULL when called from usb_serial_disconnect */
-	if (filp && (tty_hung_up_p(filp))) {
+	if ((filp && (tty_hung_up_p(filp))) || port->serial->disconnected) {
+		mutex_unlock(&port->serial->disc_mutex);
 		return;
 	}
+	mutex_unlock(&port->serial->disc_mutex);
 
 	port->tty->closing = 1;