asus-laptop: use attribute group to manage attributes

Instead of registering (and removing) every attribute individually
switch to using sysfs attribute group. This makes sure that we
properly unwind and do not try to remove non-existent attributes which
may not be safe to do in the future.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/platform/x86/asus-laptop.c

@@ -1200,82 +1200,70 @@ static void asus_acpi_notify(struct acpi_device *device, u32 event)
 
 static DEVICE_ATTR(infos, S_IRUGO, show_infos, NULL);
 static DEVICE_ATTR(wlan, S_IRUGO | S_IWUSR, show_wlan, store_wlan);
-static DEVICE_ATTR(bluetooth, S_IRUGO | S_IWUSR, show_bluetooth,
-		   store_bluetooth);
+static DEVICE_ATTR(bluetooth, S_IRUGO | S_IWUSR,
+		   show_bluetooth, store_bluetooth);
 static DEVICE_ATTR(display, S_IRUGO | S_IWUSR, show_disp, store_disp);
 static DEVICE_ATTR(ledd, S_IRUGO | S_IWUSR, show_ledd, store_ledd);
 static DEVICE_ATTR(ls_level, S_IRUGO | S_IWUSR, show_lslvl, store_lslvl);
 static DEVICE_ATTR(ls_switch, S_IRUGO | S_IWUSR, show_lssw, store_lssw);
 static DEVICE_ATTR(gps, S_IRUGO | S_IWUSR, show_gps, store_gps);
 
-static void asus_sysfs_exit(struct asus_laptop *asus)
-{
-	struct platform_device *device = asus->platform_device;
-
-	device_remove_file(&device->dev, &dev_attr_infos);
-	device_remove_file(&device->dev, &dev_attr_wlan);
-	device_remove_file(&device->dev, &dev_attr_bluetooth);
-	device_remove_file(&device->dev, &dev_attr_display);
-	device_remove_file(&device->dev, &dev_attr_ledd);
-	device_remove_file(&device->dev, &dev_attr_ls_switch);
-	device_remove_file(&device->dev, &dev_attr_ls_level);
-	device_remove_file(&device->dev, &dev_attr_gps);
-}
+static struct attribute *asus_attributes[] = {
+	&dev_attr_infos.attr,
+	&dev_attr_wlan.attr,
+	&dev_attr_bluetooth.attr,
+	&dev_attr_display.attr,
+	&dev_attr_ledd.attr,
+	&dev_attr_ls_level.attr,
+	&dev_attr_ls_switch.attr,
+	&dev_attr_gps.attr,
+	NULL
+};
 
-static int asus_sysfs_init(struct asus_laptop *asus)
+static mode_t asus_sysfs_is_visible(struct kobject *kobj,
+				    struct attribute *attr,
+				    int idx)
 {
-	struct platform_device *device = asus->platform_device;
-	int err;
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct platform_device *pdev = to_platform_device(dev);
+	struct asus_laptop *asus = platform_get_drvdata(pdev);
+	acpi_handle handle = asus->handle;
+	bool supported;
 
-	err = device_create_file(&device->dev, &dev_attr_infos);
-	if (err)
-		return err;
+	if (attr == &dev_attr_wlan.attr) {
+		supported = !acpi_check_handle(handle, METHOD_WLAN, NULL);
 
-	if (!acpi_check_handle(asus->handle, METHOD_WLAN, NULL)) {
-		err = device_create_file(&device->dev, &dev_attr_wlan);
-		if (err)
-			return err;
-	}
-
-	if (!acpi_check_handle(asus->handle, METHOD_BLUETOOTH, NULL)) {
-		err = device_create_file(&device->dev, &dev_attr_bluetooth);
-		if (err)
-			return err;
-	}
+	} else if (attr == &dev_attr_bluetooth.attr) {
+		supported = !acpi_check_handle(handle, METHOD_BLUETOOTH, NULL);
 
-	if (!acpi_check_handle(asus->handle, METHOD_SWITCH_DISPLAY, NULL)) {
-		err = device_create_file(&device->dev, &dev_attr_display);
-		if (err)
-			return err;
-	}
+	} else if (attr == &dev_attr_display.attr) {
+		supported = !acpi_check_handle(handle, METHOD_SWITCH_DISPLAY, NULL);
 
-	if (!acpi_check_handle(asus->handle, METHOD_LEDD, NULL)) {
-		err = device_create_file(&device->dev, &dev_attr_ledd);
-		if (err)
-			return err;
-	}
+	} else if (attr == &dev_attr_ledd.attr) {
+		supported = !acpi_check_handle(handle, METHOD_LEDD, NULL);
 
-	if (!acpi_check_handle(asus->handle, METHOD_ALS_CONTROL, NULL) &&
-	    !acpi_check_handle(asus->handle, METHOD_ALS_LEVEL, NULL)) {
-		err = device_create_file(&device->dev, &dev_attr_ls_switch);
-		if (err)
-			return err;
-		err = device_create_file(&device->dev, &dev_attr_ls_level);
-		if (err)
-			return err;
-	}
+	} else if (attr == &dev_attr_ls_switch.attr ||
+		   attr == &dev_attr_ls_level.attr) {
+		supported = !acpi_check_handle(handle, METHOD_ALS_CONTROL, NULL) &&
+			    !acpi_check_handle(handle, METHOD_ALS_LEVEL, NULL);
 
-	if (!acpi_check_handle(asus->handle, METHOD_GPS_ON, NULL) &&
-	    !acpi_check_handle(asus->handle, METHOD_GPS_OFF, NULL) &&
-	    !acpi_check_handle(asus->handle, METHOD_GPS_STATUS, NULL)) {
-		err = device_create_file(&device->dev, &dev_attr_gps);
-		if (err)
-			return err;
+	} else if (attr == &dev_attr_gps.attr) {
+		supported = !acpi_check_handle(handle, METHOD_GPS_ON, NULL) &&
+			    !acpi_check_handle(handle, METHOD_GPS_OFF, NULL) &&
+			    !acpi_check_handle(handle, METHOD_GPS_STATUS, NULL);
+	} else {
+		supported = true;
 	}
 
-	return err;
+	return supported ? attr->mode : 0;
 }
 
+
+static const struct attribute_group asus_attr_group = {
+	.is_visible	= asus_sysfs_is_visible,
+	.attrs		= asus_attributes,
+};
+
 static int asus_platform_init(struct asus_laptop *asus)
 {
 	int result;
@@ -1289,13 +1277,14 @@ static int asus_platform_init(struct asus_laptop *asus)
 	if (result)
 		goto fail_platform_device;
 
-	result = asus_sysfs_init(asus);
+	result = sysfs_create_group(&asus->platform_device->dev.kobj,
+				    &asus_attr_group);
 	if (result)
 		goto fail_sysfs;
+
 	return 0;
 
 fail_sysfs:
-	asus_sysfs_exit(asus);
 	platform_device_del(asus->platform_device);
 fail_platform_device:
 	platform_device_put(asus->platform_device);
@@ -1304,7 +1293,7 @@ static int asus_platform_init(struct asus_laptop *asus)
 
 static void asus_platform_exit(struct asus_laptop *asus)
 {
-	asus_sysfs_exit(asus);
+	sysfs_remove_group(&asus->platform_device->dev.kobj, &asus_attr_group);
 	platform_device_unregister(asus->platform_device);
 }