]> err.no Git - linux-2.6/commitdiff
USB: Phidgets should check create_device_file() return value
authorSean Young <sean@mess.org>
Fri, 11 Aug 2006 09:28:28 +0000 (09:28 +0000)
committerGreg Kroah-Hartman <gregkh@suse.de>
Wed, 27 Sep 2006 18:58:49 +0000 (11:58 -0700)
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
drivers/usb/misc/phidgetmotorcontrol.c
drivers/usb/misc/phidgetservo.c

index 3f508957def915e590a9eb4313db6b44ff537da3..9a8d137d39f91d75dd9273ba16ef13adfbf6ffa6 100644 (file)
@@ -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);
+       for (i=0; i<ifkit->outputs; i++ ) {
+               rc = device_create_file(kit->dev, &dev_output_attrs[i]);
+               if (rc)
+                       goto out2;
        }
 
-       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);
+       for (i=0; i<ifkit->inputs; i++ ) {
+               rc = device_create_file(kit->dev, &dev_input_attrs[i]);
+               if (rc)
+                       goto out3;
        }
 
-       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);
+       for (i=0; i<ifkit->sensors; i++ ) {
+               rc = device_create_file(kit->dev, &dev_sensor_attrs[i]);
+               if (rc)
+                       goto out4;
        }
-       if (ifkit->sensors == 8)
-               device_create_file(kit->dev, &dev_attr_sensor8);
 
-       if (ifkit->has_lcd)
-               device_create_file(kit->dev, &dev_attr_lcd);
+       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);
-       }
+       for (i=0; i<kit->ifkit->outputs; i++)
+               device_remove_file(kit->dev, &dev_output_attrs[i]);
 
-       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);
-       }
+       for (i=0; i<kit->ifkit->inputs; i++)
+               device_remove_file(kit->dev, &dev_input_attrs[i]);
 
-       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);
+       for (i=0; i<kit->ifkit->sensors; i++)
+               device_remove_file(kit->dev, &dev_sensor_attrs[i]);
 
-       if (kit->ifkit->has_lcd)
+       if (kit->ifkit->has_lcd) {
                device_remove_file(kit->dev, &dev_attr_lcd);
+               remove_lcd_files(kit);
+       }
 
        device_unregister(kit->dev);
 
index d9ac7f97f8c898b959e6702e1994ab795716ff4a..6b59b620d616b9848d59ba1bf78a91a054f697f5 100644 (file)
@@ -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);
 
index 66be9513fd6f6f802c2faa3cd86416046970e61c..7163f05c5b27063eb18b7554372fe99280205c8b 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * 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);