Input: rework handle creation code

 - consolidate code for binding handlers to a device
 - return error codes from handlers connect() methods back to input
   core and log failures

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/char/keyboard.c

@@ -41,7 +41,6 @@
 #include <linux/input.h>
 #include <linux/reboot.h>
 
-static void kbd_disconnect(struct input_handle *handle);
 extern void ctrl_alt_del(void);
 
 /*
@@ -1260,36 +1259,49 @@ static void kbd_event(struct input_handle *handle, unsigned int event_type,
  * likes it, it can open it and get events from it. In this (kbd_connect)
  * function, we should decide which VT to bind that keyboard to initially.
  */
-static struct input_handle *kbd_connect(struct input_handler *handler,
-					struct input_dev *dev,
-					const struct input_device_id *id)
+static int kbd_connect(struct input_handler *handler, struct input_dev *dev,
+			const struct input_device_id *id)
 {
 	struct input_handle *handle;
+	int error;
 	int i;
 
 	for (i = KEY_RESERVED; i < BTN_MISC; i++)
 		if (test_bit(i, dev->keybit))
 			break;
 
 	if (i == BTN_MISC && !test_bit(EV_SND, dev->evbit))
-		return NULL;
+		return -ENODEV;
 
 	handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
 	if (!handle)
-		return NULL;
+		return -ENOMEM;
 
 	handle->dev = dev;
 	handle->handler = handler;
 	handle->name = "kbd";
 
-	input_open_device(handle);
+	error = input_register_handle(handle);
+	if (error)
+		goto err_free_handle;
+
+	error = input_open_device(handle);
+	if (error)
+		goto err_unregister_handle;
+
+	return 0;
 
-	return handle;
+ err_unregister_handle:
+	input_unregister_handle(handle);
+ err_free_handle:
+	kfree(handle);
+	return error;
 }
 
 static void kbd_disconnect(struct input_handle *handle)
 {
 	input_close_device(handle);
+	input_unregister_handle(handle);
 	kfree(handle);
 }
 

drivers/input/evbug.c

@@ -38,39 +38,51 @@ MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 MODULE_DESCRIPTION("Input driver event debug module");
 MODULE_LICENSE("GPL");
 
-static char evbug_name[] = "evbug";
-
 static void evbug_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)
 {
 	printk(KERN_DEBUG "evbug.c: Event. Dev: %s, Type: %d, Code: %d, Value: %d\n",
 		handle->dev->phys, type, code, value);
 }
 
-static struct input_handle *evbug_connect(struct input_handler *handler, struct input_dev *dev,
-					  const struct input_device_id *id)
+static int evbug_connect(struct input_handler *handler, struct input_dev *dev,
+			 const struct input_device_id *id)
 {
 	struct input_handle *handle;
+	int error;
 
-	if (!(handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL)))
-		return NULL;
+	handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
+	if (!handle)
+		return -ENOMEM;
 
 	handle->dev = dev;
 	handle->handler = handler;
-	handle->name = evbug_name;
+	handle->name = "evbug";
+
+	error = input_register_handle(handle);
+	if (error)
+		goto err_free_handle;
 
-	input_open_device(handle);
+	error = input_open_device(handle);
+	if (error)
+		goto err_unregister_handle;
 
 	printk(KERN_DEBUG "evbug.c: Connected device: \"%s\", %s\n", dev->name, dev->phys);
 
-	return handle;
+	return 0;
+
+ err_unregister_handle:
+	input_unregister_handle(handle);
+ err_free_handle:
+	kfree(handle);
+	return error;
 }
 
 static void evbug_disconnect(struct input_handle *handle)
 {
 	printk(KERN_DEBUG "evbug.c: Disconnected device: %s\n", handle->dev->phys);
 
 	input_close_device(handle);
-
+	input_unregister_handle(handle);
 	kfree(handle);
 }
 

drivers/input/evdev.c

@@ -605,21 +605,24 @@ static const struct file_operations evdev_fops = {
 	.flush =	evdev_flush
 };
 
-static struct input_handle *evdev_connect(struct input_handler *handler, struct input_dev *dev,
-					  const struct input_device_id *id)
+static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
+			 const struct input_device_id *id)
 {
 	struct evdev *evdev;
 	struct class_device *cdev;
+	dev_t devt;
 	int minor;
+	int error;
 
 	for (minor = 0; minor < EVDEV_MINORS && evdev_table[minor]; minor++);
 	if (minor == EVDEV_MINORS) {
 		printk(KERN_ERR "evdev: no more free evdev devices\n");
-		return NULL;
+		return -ENFILE;
 	}
 
-	if (!(evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL)))
-		return NULL;
+	evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
+	if (!evdev)
+		return -ENOMEM;
 
 	INIT_LIST_HEAD(&evdev->list);
 	init_waitqueue_head(&evdev->wait);
@@ -634,22 +637,44 @@ static struct input_handle *evdev_connect(struct input_handler *handler, struct
 
 	evdev_table[minor] = evdev;
 
-	cdev = class_device_create(&input_class, &dev->cdev,
-			MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor),
-			dev->cdev.dev, evdev->name);
+	devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor),
+
+	cdev = class_device_create(&input_class, &dev->cdev, devt,
+				   dev->cdev.dev, evdev->name);
+	if (IS_ERR(cdev)) {
+		error = PTR_ERR(cdev);
+		goto err_free_evdev;
+	}
 
 	/* temporary symlink to keep userspace happy */
-	sysfs_create_link(&input_class.subsys.kset.kobj, &cdev->kobj,
-			  evdev->name);
+	error = sysfs_create_link(&input_class.subsys.kset.kobj,
+				  &cdev->kobj, evdev->name);
+	if (error)
+		goto err_cdev_destroy;
+
+	error = input_register_handle(&evdev->handle);
+	if (error)
+		goto err_remove_link;
 
-	return &evdev->handle;
+	return 0;
+
+ err_remove_link:
+	sysfs_remove_link(&input_class.subsys.kset.kobj, evdev->name);
+ err_cdev_destroy:
+	class_device_destroy(&input_class, devt);
+ err_free_evdev:
+	kfree(evdev);
+	evdev_table[minor] = NULL;
+	return error;
 }
 
 static void evdev_disconnect(struct input_handle *handle)
 {
 	struct evdev *evdev = handle->private;
 	struct evdev_list *list;
 
+	input_unregister_handle(handle);
+
 	sysfs_remove_link(&input_class.subsys.kset.kobj, evdev->name);
 	class_device_destroy(&input_class,
 			MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + evdev->minor));

drivers/input/input.c

@@ -380,12 +380,6 @@ static int input_default_setkeycode(struct input_dev *dev,
 }
 
 
-static void input_link_handle(struct input_handle *handle)
-{
-	list_add_tail(&handle->d_node, &handle->dev->h_list);
-	list_add_tail(&handle->h_node, &handle->handler->h_list);
-}
-
 #define MATCH_BIT(bit, max) \
 		for (i = 0; i < NBITS(max); i++) \
 			if ((id->bit[i] & dev->bit[i]) != id->bit[i]) \
@@ -432,6 +426,29 @@ static const struct input_device_id *input_match_device(const struct input_devic
 	return NULL;
 }
 
+static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
+{
+	const struct input_device_id *id;
+	int error;
+
+	if (handler->blacklist && input_match_device(handler->blacklist, dev))
+		return -ENODEV;
+
+	id = input_match_device(handler->id_table, dev);
+	if (!id)
+		return -ENODEV;
+
+	error = handler->connect(handler, dev, id);
+	if (error && error != -ENODEV)
+		printk(KERN_ERR
+			"input: failed to attach handler %s to device %s, "
+			"error: %d\n",
+			handler->name, kobject_name(&dev->cdev.kobj), error);
+
+	return error;
+}
+
+
 #ifdef CONFIG_PROC_FS
 
 static struct proc_dir_entry *proc_bus_input_dir;
@@ -1032,9 +1049,7 @@ EXPORT_SYMBOL(input_free_device);
 int input_register_device(struct input_dev *dev)
 {
 	static atomic_t input_no = ATOMIC_INIT(0);
-	struct input_handle *handle;
 	struct input_handler *handler;
-	const struct input_device_id *id;
 	const char *path;
 	int error;
 
@@ -1074,13 +1089,7 @@ int input_register_device(struct input_dev *dev)
 	kfree(path);
 
 	list_for_each_entry(handler, &input_handler_list, node)
-		if (!handler->blacklist || !input_match_device(handler->blacklist, dev))
-			if ((id = input_match_device(handler->id_table, dev)))
-				if ((handle = handler->connect(handler, dev, id))) {
-					input_link_handle(handle);
-					if (handler->start)
-						handler->start(handle);
-				}
+		input_attach_handler(dev, handler);
 
 	input_wakeup_procfs_readers();
 
@@ -1090,7 +1099,7 @@ EXPORT_SYMBOL(input_register_device);
 
 void input_unregister_device(struct input_dev *dev)
 {
-	struct list_head *node, *next;
+	struct input_handle *handle, *next;
 	int code;
 
 	for (code = 0; code <= KEY_MAX; code++)
@@ -1100,12 +1109,9 @@ void input_unregister_device(struct input_dev *dev)
 
 	del_timer_sync(&dev->timer);
 
-	list_for_each_safe(node, next, &dev->h_list) {
-		struct input_handle * handle = to_handle(node);
-		list_del_init(&handle->d_node);
-		list_del_init(&handle->h_node);
+	list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
 		handle->handler->disconnect(handle);
-	}
+	WARN_ON(!list_empty(&dev->h_list));
 
 	list_del_init(&dev->node);
 
@@ -1118,8 +1124,6 @@ EXPORT_SYMBOL(input_unregister_device);
 int input_register_handler(struct input_handler *handler)
 {
 	struct input_dev *dev;
-	struct input_handle *handle;
-	const struct input_device_id *id;
 
 	INIT_LIST_HEAD(&handler->h_list);
 
@@ -1133,13 +1137,7 @@ int input_register_handler(struct input_handler *handler)
 	list_add_tail(&handler->node, &input_handler_list);
 
 	list_for_each_entry(dev, &input_dev_list, node)
-		if (!handler->blacklist || !input_match_device(handler->blacklist, dev))
-			if ((id = input_match_device(handler->id_table, dev)))
-				if ((handle = handler->connect(handler, dev, id))) {
-					input_link_handle(handle);
-					if (handler->start)
-						handler->start(handle);
-				}
+		input_attach_handler(dev, handler);
 
 	input_wakeup_procfs_readers();
 	return 0;
@@ -1148,14 +1146,11 @@ EXPORT_SYMBOL(input_register_handler);
 
 void input_unregister_handler(struct input_handler *handler)
 {
-	struct list_head *node, *next;
+	struct input_handle *handle, *next;
 
-	list_for_each_safe(node, next, &handler->h_list) {
-		struct input_handle * handle = to_handle_h(node);
-		list_del_init(&handle->h_node);
-		list_del_init(&handle->d_node);
+	list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
 		handler->disconnect(handle);
-	}
+	WARN_ON(!list_empty(&handler->h_list));
 
 	list_del_init(&handler->node);
 
@@ -1166,6 +1161,27 @@ void input_unregister_handler(struct input_handler *handler)
 }
 EXPORT_SYMBOL(input_unregister_handler);
 
+int input_register_handle(struct input_handle *handle)
+{
+	struct input_handler *handler = handle->handler;
+
+	list_add_tail(&handle->d_node, &handle->dev->h_list);
+	list_add_tail(&handle->h_node, &handler->h_list);
+
+	if (handler->start)
+		handler->start(handle);
+
+	return 0;
+}
+EXPORT_SYMBOL(input_register_handle);
+
+void input_unregister_handle(struct input_handle *handle)
+{
+	list_del_init(&handle->h_node);
+	list_del_init(&handle->d_node);
+}
+EXPORT_SYMBOL(input_unregister_handle);
+
 static int input_open_file(struct inode *inode, struct file *file)
 {
 	struct input_handler *handler = input_table[iminor(inode) >> 5];