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@@ -198,6 +198,7 @@ static struct usb_device_id tower_table [] = {
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};
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MODULE_DEVICE_TABLE (usb, tower_table);
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+static DEFINE_MUTEX(open_disc_mutex);
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#define LEGO_USB_TOWER_MINOR_BASE 160
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@@ -350,25 +351,31 @@ static int tower_open (struct inode *inode, struct file *file)
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goto exit;
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}
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+ mutex_lock(&open_disc_mutex);
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dev = usb_get_intfdata(interface);
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if (!dev) {
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+ mutex_unlock(&open_disc_mutex);
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retval = -ENODEV;
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goto exit;
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}
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/* lock this device */
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if (down_interruptible (&dev->sem)) {
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+ mutex_unlock(&open_disc_mutex);
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retval = -ERESTARTSYS;
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goto exit;
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}
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+
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/* allow opening only once */
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if (dev->open_count) {
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+ mutex_unlock(&open_disc_mutex);
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retval = -EBUSY;
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goto unlock_exit;
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}
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dev->open_count = 1;
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+ mutex_unlock(&open_disc_mutex);
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/* reset the tower */
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result = usb_control_msg (dev->udev,
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@@ -437,9 +444,10 @@ static int tower_release (struct inode *inode, struct file *file)
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if (dev == NULL) {
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dbg(1, "%s: object is NULL", __FUNCTION__);
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retval = -ENODEV;
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- goto exit;
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+ goto exit_nolock;
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}
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+ mutex_lock(&open_disc_mutex);
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if (down_interruptible (&dev->sem)) {
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retval = -ERESTARTSYS;
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goto exit;
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@@ -468,6 +476,8 @@ unlock_exit:
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up (&dev->sem);
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exit:
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+ mutex_unlock(&open_disc_mutex);
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+exit_nolock:
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dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
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return retval;
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}
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@@ -989,6 +999,7 @@ static void tower_disconnect (struct usb_interface *interface)
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dbg(2, "%s: enter", __FUNCTION__);
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dev = usb_get_intfdata (interface);
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+ mutex_lock(&open_disc_mutex);
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usb_set_intfdata (interface, NULL);
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minor = dev->minor;
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@@ -997,6 +1008,7 @@ static void tower_disconnect (struct usb_interface *interface)
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usb_deregister_dev (interface, &tower_class);
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down (&dev->sem);
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+ mutex_unlock(&open_disc_mutex);
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/* if the device is not opened, then we clean up right now */
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if (!dev->open_count) {
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