driver model: make classes and interfaces use kobject infrastructure.

Like the other objects, this allows a decent bit of cleanup. Details include:

- use rwsem in subsytem, instead of one in struct device_class.

- use refcount in struct kobject, instead of one in struct device_class.

- kill class's present flag. 

- kill class_list, since we can just use class_subsys's. 

- make interfaces instances of their class's subsystem. This allows us to 
kill struct device_class::intf_list, and struct device_interface::node.

drivers/base/class.c

@@ -2,6 +2,8 @@
  * class.c - basic device class management
  */
 
+#undef DEBUG
+
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -101,12 +103,12 @@ int devclass_add_driver(struct device_driver * drv)
 {
 	struct device_class * cls = get_devclass(drv->devclass);
 	if (cls) {
-		down_write(&cls->rwsem);
+		down_write(&cls->subsys.rwsem);
 		pr_debug("device class %s: adding driver %s:%s\n",
 			 cls->name,drv->bus->name,drv->name);
 		list_add_tail(&drv->class_list,&cls->drivers);
 		devclass_drv_link(drv);
-		up_write(&cls->rwsem);
+		up_write(&cls->subsys.rwsem);
 	}
 	return 0;
 }
@@ -115,12 +117,12 @@ void devclass_remove_driver(struct device_driver * drv)
 {
 	struct device_class * cls = drv->devclass;
 	if (cls) {
-		down_write(&cls->rwsem);
+		down_write(&cls->subsys.rwsem);
 		pr_debug("device class %s: removing driver %s:%s\n",
 			 cls->name,drv->bus->name,drv->name);
 		list_del_init(&drv->class_list);
 		devclass_drv_unlink(drv);
-		up_write(&cls->rwsem);
+		up_write(&cls->subsys.rwsem);
 		put_devclass(cls);
 	}
 }
@@ -163,7 +165,7 @@ int devclass_add_device(struct device * dev)
 	if (dev->driver) {
 		cls = get_devclass(dev->driver->devclass);
 		if (cls) {
-			down_write(&cls->rwsem);
+			down_write(&cls->subsys.rwsem);
 			pr_debug("device class %s: adding device %s\n",
 				 cls->name,dev->name);
 			if (cls->add_device) 
@@ -176,7 +178,7 @@ int devclass_add_device(struct device * dev)
 			/* notify userspace (call /sbin/hotplug) */
 			class_hotplug (dev, "add");
 
-			up_write(&cls->rwsem);
+			up_write(&cls->subsys.rwsem);
 			if (error)
 				put_devclass(cls);
 		}
@@ -191,7 +193,7 @@ void devclass_remove_device(struct device * dev)
 	if (dev->driver) {
 		cls = dev->driver->devclass;
 		if (cls) {
-			down_write(&cls->rwsem);
+			down_write(&cls->subsys.rwsem);
 			pr_debug("device class %s: removing device %s\n",
 				 cls->name,dev->name);
 			interface_remove(cls,dev);
@@ -202,7 +204,7 @@ void devclass_remove_device(struct device * dev)
 
 			if (cls->remove_device)
 				cls->remove_device(dev);
-			up_write(&cls->rwsem);
+			up_write(&cls->subsys.rwsem);
 			put_devclass(cls);
 		}
 	}
@@ -210,34 +212,20 @@ void devclass_remove_device(struct device * dev)
 
 struct device_class * get_devclass(struct device_class * cls)
 {
-	struct device_class * ret = cls;
-	spin_lock(&device_lock);
-	if (cls && cls->present && atomic_read(&cls->refcount) > 0)
-		atomic_inc(&cls->refcount);
-	else
-		ret = NULL;
-	spin_unlock(&device_lock);
-	return ret;
+	return cls ? container_of(subsys_get(&cls->subsys),struct device_class,subsys) : NULL;
 }
 
 void put_devclass(struct device_class * cls)
 {
-	if (atomic_dec_and_lock(&cls->refcount,&device_lock)) {
-		list_del_init(&cls->node);
-		spin_unlock(&device_lock);
-	}
+	subsys_put(&cls->subsys);
 }
 
 
 int devclass_register(struct device_class * cls)
 {
 	INIT_LIST_HEAD(&cls->drivers);
-	INIT_LIST_HEAD(&cls->intf_list);
-	init_rwsem(&cls->rwsem);
-	atomic_set(&cls->refcount,2);
-	cls->present = 1;
-	pr_debug("device class '%s': registering\n",cls->name);
 
+	pr_debug("device class '%s': registering\n",cls->name);
 	strncpy(cls->subsys.kobj.name,cls->name,KOBJ_NAME_LEN);
 	cls->subsys.parent = &class_subsys;
 	subsystem_register(&cls->subsys);
@@ -250,23 +238,15 @@ int devclass_register(struct device_class * cls)
 	cls->drvsubsys.parent = &cls->subsys;
 	subsystem_register(&cls->drvsubsys);
 
-	spin_lock(&device_lock);
-	list_add_tail(&cls->node,&class_list);
-	spin_unlock(&device_lock);
-	put_devclass(cls);
 	return 0;
 }
 
 void devclass_unregister(struct device_class * cls)
 {
-	spin_lock(&device_lock);
-	cls->present = 0;
-	spin_unlock(&device_lock);
 	pr_debug("device class '%s': unregistering\n",cls->name);
 	subsystem_unregister(&cls->drvsubsys);
 	subsystem_unregister(&cls->devsubsys);
 	subsystem_unregister(&cls->subsys);
-	put_devclass(cls);
 }
 
 static int __init class_subsys_init(void)
@@ -276,6 +256,8 @@ static int __init class_subsys_init(void)
 
 core_initcall(class_subsys_init);
 
+EXPORT_SYMBOL(devclass_create_file);
+EXPORT_SYMBOL(devclass_remove_file);
 EXPORT_SYMBOL(devclass_register);
 EXPORT_SYMBOL(devclass_unregister);
 EXPORT_SYMBOL(get_devclass);

drivers/base/intf.c

@@ -10,7 +10,7 @@
 #include "base.h"
 
 
-#define to_intf(node) container_of(node,struct device_interface,node)
+#define to_intf(node) container_of(node,struct device_interface,kobj.entry)
 
 /**
  * intf_dev_link - symlink from interface's directory to device's directory
@@ -34,22 +34,18 @@ static void intf_dev_unlink(struct intf_data * data)
 
 int interface_register(struct device_interface * intf)
 {
-	struct device_class * cls = intf->devclass;
+	struct device_class * cls = get_devclass(intf->devclass);
+	int error = 0;
 
 	if (cls) {
 		pr_debug("register interface '%s' with class '%s'\n",
 			 intf->name,cls->name);
-		kobject_init(&intf->kobj);
 		strncpy(intf->kobj.name,intf->name,KOBJ_NAME_LEN);
 		intf->kobj.subsys = &cls->subsys;
 		kobject_register(&intf->kobj);
-
-		spin_lock(&device_lock);
-		list_add_tail(&intf->node,&cls->intf_list);
-		spin_unlock(&device_lock);
-		return 0;
-	}
-	return -EINVAL;
+	} else
+		error = -EINVAL;
+	return error;
 }
 
 void interface_unregister(struct device_interface * intf)
@@ -57,9 +53,6 @@ void interface_unregister(struct device_interface * intf)
 	pr_debug("unregistering interface '%s' from class '%s'\n",
 		 intf->name,intf->devclass->name);
 	kobject_unregister(&intf->kobj);
-	spin_lock(&device_lock);
-	list_del_init(&intf->node);
-	spin_unlock(&device_lock);
 }
 
 int interface_add(struct device_class * cls, struct device * dev)
@@ -69,7 +62,7 @@ int interface_add(struct device_class * cls, struct device * dev)
 
 	pr_debug("adding '%s' to %s class interfaces\n",dev->name,cls->name);
 
-	list_for_each(node,&cls->intf_list) {
+	list_for_each(node,&cls->subsys.list) {
 		struct device_interface * intf = to_intf(node);
 		if (intf->add_device) {
 			error = intf->add_device(dev);
@@ -89,30 +82,25 @@ void interface_remove(struct device_class * cls, struct device * dev)
 
 	pr_debug("remove '%s' from %s class interfaces: ",dev->name,cls->name);
 
-	spin_lock(&device_lock);
 	list_for_each_safe(node,next,&dev->intf_list) {
 		struct intf_data * intf_data = container_of(node,struct intf_data,node);
 		list_del_init(&intf_data->node);
-		spin_unlock(&device_lock);
 
 		intf_dev_unlink(intf_data);
 		pr_debug("%s ",intf_data->intf->name);
 		if (intf_data->intf->remove_device)
 			intf_data->intf->remove_device(intf_data);
-
-		spin_lock(&device_lock);
 	}
-	spin_unlock(&device_lock);
 	pr_debug("\n");
 }
 
 int interface_add_data(struct intf_data * data)
 {
-	spin_lock(&device_lock);
+	down_write(&data->intf->devclass->subsys.rwsem);
 	list_add_tail(&data->node,&data->dev->intf_list);
-	data->intf_num = ++data->intf->devnum;
-	spin_unlock(&device_lock);
+	data->intf_num = data->intf->devnum++;
 	intf_dev_link(data);
+	up_write(&data->intf->devclass->subsys.rwsem);
 	return 0;
 }
 

include/linux/device.h

@@ -153,19 +153,12 @@ extern void driver_remove_file(struct device_driver *, struct driver_attribute *
  */
 struct device_class {
 	char			* name;
-	struct rw_semaphore	rwsem;
-
-	atomic_t		refcount;
-	u32			present;
-
 	u32			devnum;
 
 	struct subsystem	subsys;
 	struct subsystem	devsubsys;
 	struct subsystem	drvsubsys;
-	struct list_head	node;
 	struct list_head	drivers;
-	struct list_head	intf_list;
 
 	int	(*add_device)(struct device *);
 	void	(*remove_device)(struct device *);
@@ -215,7 +208,6 @@ struct device_interface {
 	struct device_class	* devclass;
 
 	struct kobject		kobj;
-	struct list_head	node;
 	struct list_head	devices;
 
 	u32			devnum;