USB: Phidgets should check create_device_file() return value

device_create_file() could fail, add proper error paths for this condition.
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/phidgetkit.c

@@ -193,8 +193,11 @@ static ssize_t lcd_line_##number(struct device *dev,			\
 	struct interfacekit *kit = dev_get_drvdata(dev);		\
 	change_string(kit, buf, number - 1);				\
 	return count;							\
-}									\
-static DEVICE_ATTR(lcd_line_##number, S_IWUGO, NULL, lcd_line_##number);
+}
+
+#define lcd_line_attr(number)						\
+	__ATTR(lcd_line_##number, S_IWUGO, NULL, lcd_line_##number)
+
 set_lcd_line(1);
 set_lcd_line(2);
 
@@ -232,15 +235,22 @@ exit:
 	kfree(buffer);
 	return retval;
 }
-static DEVICE_ATTR(backlight, S_IWUGO, NULL, set_backlight);
+
+static struct device_attribute dev_lcd_line_attrs[] = {
+	lcd_line_attr(1),
+	lcd_line_attr(2),
+	__ATTR(backlight, S_IWUGO, NULL, set_backlight)
+};
 
 static void remove_lcd_files(struct interfacekit *kit)
 {
+	int i;
+
 	if (kit->lcd_files_on) {
 		dev_dbg(&kit->udev->dev, "Removing lcd files\n");
-		device_remove_file(kit->dev, &dev_attr_lcd_line_1);
-		device_remove_file(kit->dev, &dev_attr_lcd_line_2);
-		device_remove_file(kit->dev, &dev_attr_backlight);
+
+		for (i=0; i<ARRAY_SIZE(dev_lcd_line_attrs); i++)
+			device_remove_file(kit->dev, &dev_lcd_line_attrs[i]);
 	}
 }
 
@@ -248,6 +258,7 @@ static ssize_t enable_lcd_files(struct device *dev, struct device_attribute *att
 {
 	struct interfacekit *kit = dev_get_drvdata(dev);
 	int enable;
+	int i, rc;
 	
 	if (kit->ifkit->has_lcd == 0)
 		return -ENODEV;
@@ -258,9 +269,12 @@ static ssize_t enable_lcd_files(struct device *dev, struct device_attribute *att
 	if (enable) {
 		if (!kit->lcd_files_on) {
 			dev_dbg(&kit->udev->dev, "Adding lcd files\n");
-			device_create_file(kit->dev, &dev_attr_lcd_line_1);
-			device_create_file(kit->dev, &dev_attr_lcd_line_2);
-			device_create_file(kit->dev, &dev_attr_backlight);
+			for (i=0; i<ARRAY_SIZE(dev_lcd_line_attrs); i++) {
+				rc = device_create_file(kit->dev,
+					&dev_lcd_line_attrs[i]);
+				if (rc)
+					goto out;
+			}
 			kit->lcd_files_on = 1;
 		}
 	} else {
@@ -271,7 +285,13 @@ static ssize_t enable_lcd_files(struct device *dev, struct device_attribute *att
 	}
 	
 	return count;
+out:
+	while (i-- > 0)
+		device_remove_file(kit->dev, &dev_lcd_line_attrs[i]);
+
+	return rc;
 }
+
 static DEVICE_ATTR(lcd, S_IWUGO, NULL, enable_lcd_files);
 
 static void interfacekit_irq(struct urb *urb, struct pt_regs *regs)
@@ -403,9 +423,12 @@ static ssize_t show_output##value(struct device *dev, 			\
 	struct interfacekit *kit = dev_get_drvdata(dev);		\
 									\
 	return sprintf(buf, "%d\n", !!test_bit(value - 1, &kit->outputs));\
-}									\
-static DEVICE_ATTR(output##value, S_IWUGO | S_IRUGO,			\
-		show_output##value, set_output##value);
+}
+
+#define output_attr(value)						\
+	__ATTR(output##value, S_IWUGO | S_IRUGO,			\
+		show_output##value, set_output##value)
+
 show_set_output(1);
 show_set_output(2);
 show_set_output(3);
@@ -423,14 +446,24 @@ show_set_output(14);
 show_set_output(15);
 show_set_output(16);
 
+static struct device_attribute dev_output_attrs[] = {
+	output_attr(1), output_attr(2), output_attr(3), output_attr(4),
+	output_attr(5), output_attr(6), output_attr(7), output_attr(8),
+	output_attr(9), output_attr(10), output_attr(11), output_attr(12),
+	output_attr(13), output_attr(14), output_attr(15), output_attr(16)
+};
+
 #define show_input(value)	\
-static ssize_t show_input##value(struct device *dev, struct device_attribute *attr, char *buf)	\
+static ssize_t show_input##value(struct device *dev, 			\
+			struct device_attribute *attr, char *buf)	\
 {									\
 	struct interfacekit *kit = dev_get_drvdata(dev);		\
 									\
 	return sprintf(buf, "%d\n", (int)kit->inputs[value - 1]);	\
-}									\
-static DEVICE_ATTR(input##value, S_IRUGO, show_input##value, NULL);
+}
+
+#define input_attr(value)						\
+	__ATTR(input##value, S_IRUGO, show_input##value, NULL)
 
 show_input(1);
 show_input(2);
@@ -449,6 +482,13 @@ show_input(14);
 show_input(15);
 show_input(16);
 
+static struct device_attribute dev_input_attrs[] = {
+	input_attr(1), input_attr(2), input_attr(3), input_attr(4),
+	input_attr(5), input_attr(6), input_attr(7), input_attr(8),
+	input_attr(9), input_attr(10), input_attr(11), input_attr(12),
+	input_attr(13), input_attr(14), input_attr(15), input_attr(16)
+};
+
 #define show_sensor(value)	\
 static ssize_t show_sensor##value(struct device *dev,			\
 					struct device_attribute *attr,	\
@@ -457,8 +497,10 @@ static ssize_t show_sensor##value(struct device *dev,			\
 	struct interfacekit *kit = dev_get_drvdata(dev);		\
 									\
 	return sprintf(buf, "%d\n", (int)kit->sensors[value - 1]);	\
-}									\
-static DEVICE_ATTR(sensor##value, S_IRUGO, show_sensor##value, NULL);
+}
+
+#define sensor_attr(value)						\
+	__ATTR(sensor##value, S_IRUGO, show_sensor##value, NULL)
 
 show_sensor(1);
 show_sensor(2);
@@ -469,6 +511,11 @@ show_sensor(6);
 show_sensor(7);
 show_sensor(8);
 
+static struct device_attribute dev_sensor_attrs[] = {
+	sensor_attr(1), sensor_attr(2), sensor_attr(3), sensor_attr(4),
+	sensor_attr(5), sensor_attr(6), sensor_attr(7), sensor_attr(8)
+};
+
 static int interfacekit_probe(struct usb_interface *intf, const struct usb_device_id *id)
 {
 	struct usb_device *dev = interface_to_usbdev(intf);
@@ -477,7 +524,7 @@ static int interfacekit_probe(struct usb_interface *intf, const struct usb_devic
 	struct interfacekit *kit;
 	struct driver_interfacekit *ifkit;
 	int pipe, maxp, rc = -ENOMEM;
-	int bit, value;
+	int bit, value, i;
 
 	ifkit = (struct driver_interfacekit *)id->driver_info;
 	if (!ifkit)
@@ -541,74 +588,49 @@ static int interfacekit_probe(struct usb_interface *intf, const struct usb_devic
 		goto out;
 	}
 
-	if (ifkit->outputs >= 4) {
-		device_create_file(kit->dev, &dev_attr_output1);
-		device_create_file(kit->dev, &dev_attr_output2);
-		device_create_file(kit->dev, &dev_attr_output3);
-		device_create_file(kit->dev, &dev_attr_output4);
-	}
-	if (ifkit->outputs >= 8) {
-		device_create_file(kit->dev, &dev_attr_output5);
-		device_create_file(kit->dev, &dev_attr_output6);
-		device_create_file(kit->dev, &dev_attr_output7);
-		device_create_file(kit->dev, &dev_attr_output8);
-	} 
-	if (ifkit->outputs == 16) {
-		device_create_file(kit->dev, &dev_attr_output9);
-		device_create_file(kit->dev, &dev_attr_output10);
-		device_create_file(kit->dev, &dev_attr_output11);
-		device_create_file(kit->dev, &dev_attr_output12);
-		device_create_file(kit->dev, &dev_attr_output13);
-		device_create_file(kit->dev, &dev_attr_output14);
-		device_create_file(kit->dev, &dev_attr_output15);
-		device_create_file(kit->dev, &dev_attr_output16);
-	}
-
-	if (ifkit->inputs >= 4) {
-		device_create_file(kit->dev, &dev_attr_input1);
-		device_create_file(kit->dev, &dev_attr_input2);
-		device_create_file(kit->dev, &dev_attr_input3);
-		device_create_file(kit->dev, &dev_attr_input4);
-	}
-	if (ifkit->inputs >= 8) {
-		device_create_file(kit->dev, &dev_attr_input5);
-		device_create_file(kit->dev, &dev_attr_input6);
-		device_create_file(kit->dev, &dev_attr_input7);
-		device_create_file(kit->dev, &dev_attr_input8);
-	}
-	if (ifkit->inputs == 16) {
-		device_create_file(kit->dev, &dev_attr_input9);
-		device_create_file(kit->dev, &dev_attr_input10);
-		device_create_file(kit->dev, &dev_attr_input11);
-		device_create_file(kit->dev, &dev_attr_input12);
-		device_create_file(kit->dev, &dev_attr_input13);
-		device_create_file(kit->dev, &dev_attr_input14);
-		device_create_file(kit->dev, &dev_attr_input15);
-		device_create_file(kit->dev, &dev_attr_input16);
-	}
-
-	if (ifkit->sensors >= 4) {
-		device_create_file(kit->dev, &dev_attr_sensor1);
-		device_create_file(kit->dev, &dev_attr_sensor2);
-		device_create_file(kit->dev, &dev_attr_sensor3);
-		device_create_file(kit->dev, &dev_attr_sensor4);
-	}
-	if (ifkit->sensors >= 7) {
-		device_create_file(kit->dev, &dev_attr_sensor5);
-		device_create_file(kit->dev, &dev_attr_sensor6);
-		device_create_file(kit->dev, &dev_attr_sensor7);
-	}
-	if (ifkit->sensors == 8)
-		device_create_file(kit->dev, &dev_attr_sensor8);
-
-	if (ifkit->has_lcd)
-		device_create_file(kit->dev, &dev_attr_lcd);
+	for (i=0; i<ifkit->outputs; i++ ) {
+		rc = device_create_file(kit->dev, &dev_output_attrs[i]);
+		if (rc)
+			goto out2;
+	}
+
+	for (i=0; i<ifkit->inputs; i++ ) {
+		rc = device_create_file(kit->dev, &dev_input_attrs[i]);
+		if (rc)
+			goto out3;
+	}
+
+	for (i=0; i<ifkit->sensors; i++ ) {
+		rc = device_create_file(kit->dev, &dev_sensor_attrs[i]);
+		if (rc)
+			goto out4;
+	}
+
+	if (ifkit->has_lcd) {
+		rc = device_create_file(kit->dev, &dev_attr_lcd);
+		if (rc)
+			goto out4;
+
+	}
 
 	dev_info(&intf->dev, "USB PhidgetInterfaceKit %d/%d/%d attached\n",
 			ifkit->sensors, ifkit->inputs, ifkit->outputs);
 
 	return 0;
 
+out4:
+	while (i-- > 0)
+		device_remove_file(kit->dev, &dev_sensor_attrs[i]);
+
+	i = ifkit->inputs;
+out3:
+	while (i-- > 0)
+		device_remove_file(kit->dev, &dev_input_attrs[i]);
+
+	i = ifkit->outputs;
+out2:
+	while (i-- > 0)
+		device_remove_file(kit->dev, &dev_output_attrs[i]);
 out:
 	if (kit) {
 		if (kit->irq)
@@ -629,6 +651,7 @@ out:
 static void interfacekit_disconnect(struct usb_interface *interface)
 {
 	struct interfacekit *kit;
+	int i;
 
 	kit = usb_get_intfdata(interface);
 	usb_set_intfdata(interface, NULL);
@@ -641,68 +664,19 @@ static void interfacekit_disconnect(struct usb_interface *interface)
 
 	cancel_delayed_work(&kit->do_notify);
 
-	if (kit->ifkit->outputs >= 4) {
-		device_remove_file(kit->dev, &dev_attr_output1);
-		device_remove_file(kit->dev, &dev_attr_output2);
-		device_remove_file(kit->dev, &dev_attr_output3);
-		device_remove_file(kit->dev, &dev_attr_output4);
-	}
-	if (kit->ifkit->outputs >= 8) {
-		device_remove_file(kit->dev, &dev_attr_output5);
-		device_remove_file(kit->dev, &dev_attr_output6);
-		device_remove_file(kit->dev, &dev_attr_output7);
-		device_remove_file(kit->dev, &dev_attr_output8);
-	}
-	if (kit->ifkit->outputs == 16) {
-		device_remove_file(kit->dev, &dev_attr_output9);
-		device_remove_file(kit->dev, &dev_attr_output10);
-		device_remove_file(kit->dev, &dev_attr_output11);
-		device_remove_file(kit->dev, &dev_attr_output12);
-		device_remove_file(kit->dev, &dev_attr_output13);
-		device_remove_file(kit->dev, &dev_attr_output14);
-		device_remove_file(kit->dev, &dev_attr_output15);
-		device_remove_file(kit->dev, &dev_attr_output16);
-	}
-
-	if (kit->ifkit->inputs >= 4) {
-		device_remove_file(kit->dev, &dev_attr_input1);
-		device_remove_file(kit->dev, &dev_attr_input2);
-		device_remove_file(kit->dev, &dev_attr_input3);
-		device_remove_file(kit->dev, &dev_attr_input4);
-	}
-	if (kit->ifkit->inputs >= 8) {
-		device_remove_file(kit->dev, &dev_attr_input5);
-		device_remove_file(kit->dev, &dev_attr_input6);
-		device_remove_file(kit->dev, &dev_attr_input7);
-		device_remove_file(kit->dev, &dev_attr_input8);
-	}
-	if (kit->ifkit->inputs == 16) {
-		device_remove_file(kit->dev, &dev_attr_input9);
-		device_remove_file(kit->dev, &dev_attr_input10);
-		device_remove_file(kit->dev, &dev_attr_input11);
-		device_remove_file(kit->dev, &dev_attr_input12);
-		device_remove_file(kit->dev, &dev_attr_input13);
-		device_remove_file(kit->dev, &dev_attr_input14);
-		device_remove_file(kit->dev, &dev_attr_input15);
-		device_remove_file(kit->dev, &dev_attr_input16);
-	}
-
-	if (kit->ifkit->sensors >= 4) {
-		device_remove_file(kit->dev, &dev_attr_sensor1);
-		device_remove_file(kit->dev, &dev_attr_sensor2);
-		device_remove_file(kit->dev, &dev_attr_sensor3);
-		device_remove_file(kit->dev, &dev_attr_sensor4);
-	}
-	if (kit->ifkit->sensors >= 7) {
-		device_remove_file(kit->dev, &dev_attr_sensor5);
-		device_remove_file(kit->dev, &dev_attr_sensor6);
-		device_remove_file(kit->dev, &dev_attr_sensor7);
-	}
-	if (kit->ifkit->sensors == 8)
-		device_remove_file(kit->dev, &dev_attr_sensor8);
-
-	if (kit->ifkit->has_lcd)
+	for (i=0; i<kit->ifkit->outputs; i++)
+		device_remove_file(kit->dev, &dev_output_attrs[i]);
+
+	for (i=0; i<kit->ifkit->inputs; i++)
+		device_remove_file(kit->dev, &dev_input_attrs[i]);
+
+	for (i=0; i<kit->ifkit->sensors; i++)
+		device_remove_file(kit->dev, &dev_sensor_attrs[i]);
+
+	if (kit->ifkit->has_lcd) {
 		device_remove_file(kit->dev, &dev_attr_lcd);
+		remove_lcd_files(kit);
+	}
 
 	device_unregister(kit->dev);
 

drivers/usb/misc/phidgetmotorcontrol.c

@@ -215,9 +215,12 @@ static ssize_t show_speed##value(struct device *dev,			\
 	struct motorcontrol *mc = dev_get_drvdata(dev);			\
 									\
 	return sprintf(buf, "%d\n", mc->speed[value]);			\
-}									\
-static DEVICE_ATTR(speed##value, S_IWUGO | S_IRUGO,			\
-		show_speed##value, set_speed##value);
+}
+
+#define speed_attr(value) 						\
+	__ATTR(speed##value, S_IWUGO | S_IRUGO, 			\
+		show_speed##value, set_speed##value)
+
 show_set_speed(0);
 show_set_speed(1);
 
@@ -250,9 +253,12 @@ static ssize_t show_acceleration##value(struct device *dev,	 	\
 	struct motorcontrol *mc = dev_get_drvdata(dev);			\
 									\
 	return sprintf(buf, "%d\n", mc->acceleration[value]);		\
-}									\
-static DEVICE_ATTR(acceleration##value, S_IWUGO | S_IRUGO,		\
-		show_acceleration##value, set_acceleration##value);
+}
+
+#define acceleration_attr(value)	\
+	__ATTR(acceleration##value, S_IWUGO | S_IRUGO,			\
+		show_acceleration##value, set_acceleration##value)
+
 show_set_acceleration(0);
 show_set_acceleration(1);
 
@@ -264,8 +270,10 @@ static ssize_t show_current##value(struct device *dev,			\
 	struct motorcontrol *mc = dev_get_drvdata(dev);			\
 									\
 	return sprintf(buf, "%dmA\n", (int)mc->_current[value]);	\
-}									\
-static DEVICE_ATTR(current##value, S_IRUGO, show_current##value, NULL);
+}
+
+#define current_attr(value)	\
+	__ATTR(current##value, S_IRUGO, show_current##value, NULL)
 
 show_current(0);
 show_current(1);
@@ -278,14 +286,29 @@ static ssize_t show_input##value(struct device *dev,			\
 	struct motorcontrol *mc = dev_get_drvdata(dev);			\
 									\
 	return sprintf(buf, "%d\n", (int)mc->inputs[value]);		\
-}									\
-static DEVICE_ATTR(input##value, S_IRUGO, show_input##value, NULL);
+}
+
+#define input_attr(value)	\
+	__ATTR(input##value, S_IRUGO, show_input##value, NULL)
 
 show_input(0);
 show_input(1);
 show_input(2);
 show_input(3);
 
+static struct device_attribute dev_attrs[] = {
+	input_attr(0),
+	input_attr(1),
+	input_attr(2),
+	input_attr(3),
+	speed_attr(0),
+	speed_attr(1),
+	acceleration_attr(0),
+	acceleration_attr(1),
+	current_attr(0),
+	current_attr(1)
+};
+
 static int motorcontrol_probe(struct usb_interface *intf, const struct usb_device_id *id)
 {
 	struct usb_device *dev = interface_to_usbdev(intf);
@@ -293,7 +316,7 @@ static int motorcontrol_probe(struct usb_interface *intf, const struct usb_devic
 	struct usb_endpoint_descriptor *endpoint;
 	struct motorcontrol *mc;
 	int pipe, maxp, rc = -ENOMEM;
-	int bit, value;
+	int bit, value, i;
 
 	interface = intf->cur_altsetting;
 	if (interface->desc.bNumEndpoints != 1)
@@ -355,24 +378,18 @@ static int motorcontrol_probe(struct usb_interface *intf, const struct usb_devic
 		goto out;
 	}
 
-	device_create_file(mc->dev, &dev_attr_input0);
-	device_create_file(mc->dev, &dev_attr_input1);
-	device_create_file(mc->dev, &dev_attr_input2);
-	device_create_file(mc->dev, &dev_attr_input3);
-
-	device_create_file(mc->dev, &dev_attr_speed0);
-	device_create_file(mc->dev, &dev_attr_speed1);
-
-	device_create_file(mc->dev, &dev_attr_acceleration0);
-	device_create_file(mc->dev, &dev_attr_acceleration1);
-
-	device_create_file(mc->dev, &dev_attr_current0);
-	device_create_file(mc->dev, &dev_attr_current1);
+	for (i=0; i<ARRAY_SIZE(dev_attrs); i++) {
+		rc = device_create_file(mc->dev, &dev_attrs[i]);
+		if (rc)
+			goto out2;
+	}
 
 	dev_info(&intf->dev, "USB PhidgetMotorControl attached\n");
 
 	return 0;
-
+out2:
+	while (i-- > 0)
+		device_remove_file(mc->dev, &dev_attrs[i]);
 out:
 	if (mc) {
 		if (mc->irq)
@@ -393,6 +410,7 @@ out:
 static void motorcontrol_disconnect(struct usb_interface *interface)
 {
 	struct motorcontrol *mc;
+	int i;
 
 	mc = usb_get_intfdata(interface);
 	usb_set_intfdata(interface, NULL);
@@ -405,19 +423,8 @@ static void motorcontrol_disconnect(struct usb_interface *interface)
 
 	cancel_delayed_work(&mc->do_notify);
 
-	device_remove_file(mc->dev, &dev_attr_input0);
-	device_remove_file(mc->dev, &dev_attr_input1);
-	device_remove_file(mc->dev, &dev_attr_input2);
-	device_remove_file(mc->dev, &dev_attr_input3);
-
-	device_remove_file(mc->dev, &dev_attr_speed0);
-	device_remove_file(mc->dev, &dev_attr_speed1);
-
-	device_remove_file(mc->dev, &dev_attr_acceleration0);
-	device_remove_file(mc->dev, &dev_attr_acceleration1);
-
-	device_remove_file(mc->dev, &dev_attr_current0);
-	device_remove_file(mc->dev, &dev_attr_current1);
+	for (i=0; i<ARRAY_SIZE(dev_attrs); i++)
+		device_remove_file(mc->dev, &dev_attrs[i]);
 
 	device_unregister(mc->dev);
 

drivers/usb/misc/phidgetservo.c

 /*
  * USB PhidgetServo driver 1.0
  *
- * Copyright (C) 2004 Sean Young <sean@mess.org>
+ * Copyright (C) 2004, 2006 Sean Young <sean@mess.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -235,86 +235,108 @@ static ssize_t show_servo##value (struct device *dev,			\
 									\
 	return sprintf(buf, "%d.%02d\n", servo->degrees[value],		\
 				servo->minutes[value]);			\
-}									\
-static DEVICE_ATTR(servo##value, S_IWUGO | S_IRUGO,			\
-	  show_servo##value, set_servo##value);
+}
 
+#define servo_attr(value)						\
+	__ATTR(servo##value, S_IWUGO | S_IRUGO,				\
+		show_servo##value, set_servo##value)
 show_set(0);
 show_set(1);
 show_set(2);
 show_set(3);
 
+static struct device_attribute dev_attrs[] = {
+	servo_attr(0), servo_attr(1), servo_attr(2), servo_attr(3)
+};
+
 static int
 servo_probe(struct usb_interface *interface, const struct usb_device_id *id)
 {
 	struct usb_device *udev = interface_to_usbdev(interface);
 	struct phidget_servo *dev;
-	int bit, value;
+	int bit, value, rc;
+	int servo_count, i;
 
 	dev = kzalloc(sizeof (struct phidget_servo), GFP_KERNEL);
 	if (dev == NULL) {
 		dev_err(&interface->dev, "%s - out of memory\n", __FUNCTION__);
-		return -ENOMEM;
+		rc = -ENOMEM;
+		goto out;
 	}
 
 	dev->udev = usb_get_dev(udev);
 	dev->type = id->driver_info;
+	dev->dev_no = -1;
 	usb_set_intfdata(interface, dev);
 
         do {
                 bit = find_first_zero_bit(&device_no, sizeof(device_no));
                 value = test_and_set_bit(bit, &device_no);
-        } while(value);
+        } while (value);
 	dev->dev_no = bit;
 
 	dev->dev = device_create(phidget_class, &dev->udev->dev, 0,
 				 "servo%d", dev->dev_no);
 	if (IS_ERR(dev->dev)) {
-		int rc = PTR_ERR(dev->dev);
-		clear_bit(dev->dev_no, &device_no);
-		kfree(dev);
-		return rc;
+		rc = PTR_ERR(dev->dev);
+		dev->dev = NULL;
+		goto out;
 	}
 
-	device_create_file(dev->dev, &dev_attr_servo0);
-	if (dev->type & SERVO_COUNT_QUAD) {
-		device_create_file(dev->dev, &dev_attr_servo1);
-		device_create_file(dev->dev, &dev_attr_servo2);
-		device_create_file(dev->dev, &dev_attr_servo3);
+	servo_count = dev->type & SERVO_COUNT_QUAD ? 4 : 1;
+
+	for (i=0; i<servo_count; i++) {
+		rc = device_create_file(dev->dev, &dev_attrs[i]);
+		if (rc)
+			goto out2;
 	}
 
 	dev_info(&interface->dev, "USB %d-Motor PhidgetServo v%d.0 attached\n",
-		dev->type & SERVO_COUNT_QUAD ? 4 : 1,
-		dev->type & SERVO_VERSION_30 ? 3 : 2);
+		servo_count, dev->type & SERVO_VERSION_30 ? 3 : 2);
 
 	if (!(dev->type & SERVO_VERSION_30))
 		dev_info(&interface->dev,
 			 "WARNING: v2.0 not tested! Please report if it works.\n");
 
 	return 0;
+out2:
+	while (i-- > 0)
+		device_remove_file(dev->dev, &dev_attrs[i]);
+out:
+	if (dev) {
+		if (dev->dev)
+			device_unregister(dev->dev);
+		if (dev->dev_no >= 0)
+			clear_bit(dev->dev_no, &device_no);
+
+		kfree(dev);
+	}
+
+	return rc;
 }
 
 static void
 servo_disconnect(struct usb_interface *interface)
 {
 	struct phidget_servo *dev;
+	int servo_count, i;
 
 	dev = usb_get_intfdata(interface);
 	usb_set_intfdata(interface, NULL);
 
-	device_remove_file(dev->dev, &dev_attr_servo0);
-	if (dev->type & SERVO_COUNT_QUAD) {
-		device_remove_file(dev->dev, &dev_attr_servo1);
-		device_remove_file(dev->dev, &dev_attr_servo2);
-		device_remove_file(dev->dev, &dev_attr_servo3);
-	}
+	if (!dev)
+		return;
+
+	servo_count = dev->type & SERVO_COUNT_QUAD ? 4 : 1;
+
+	for (i=0; i<servo_count; i++)
+		device_remove_file(dev->dev, &dev_attrs[i]);
 
 	device_unregister(dev->dev);
 	usb_put_dev(dev->udev);
 
 	dev_info(&interface->dev, "USB %d-Motor PhidgetServo v%d.0 detached\n",
-		dev->type & SERVO_COUNT_QUAD ? 4 : 1,
-		dev->type & SERVO_VERSION_30 ? 3 : 2);
+		servo_count, dev->type & SERVO_VERSION_30 ? 3 : 2);
 
 	clear_bit(dev->dev_no, &device_no);
 	kfree(dev);