class: move driver core specific parts to a private structure

This moves the portions of struct class that are dynamic (kobject and
lock and lists) out of the main structure and into a dynamic, private,
structure.


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 107 insertions, 71 deletions

diff --git a/drivers/base/base.h b/drivers/base/base.h
index 2c9ae43..0ec372a 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -36,6 +36,33 @@ struct driver_private {
 };
 #define to_driver(obj) container_of(obj, struct driver_private, kobj)
 
+
+/**
+ * struct class_private - structure to hold the private to the driver core portions of the class structure.
+ *
+ * @subsys - the struct kset that defines this class.  This is the main kobject
+ * @children - list of class_devices associated with this class
+ * @devices - list of devices associated with this class
+ * @interfaces - list of class_interfaces associated with this class
+ * @class_dirs -
+ * @sem - semaphore to protect the children, devices, and interfaces lists.
+ * @class - pointer back to the struct class that this structure is associated
+ * with.
+ *
+ * This structure is the one that is the actual kobject allowing struct
+ * class to be statically allocated safely.  Nothing outside of the driver
+ * core should ever touch these fields.
+ */
+struct class_private {
+	struct kset subsys;
+	struct list_head devices;
+	struct list_head interfaces;
+	struct kset class_dirs;
+	struct semaphore sem;
+	struct class *class;
+};
+#define to_class(obj) container_of(obj, struct class_private, subsys.kobj)
+
 /* initialisation functions */
 extern int devices_init(void);
 extern int buses_init(void);
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 3918d0e..06f09c9 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -21,17 +21,16 @@
 #include "base.h"
 
 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
-#define to_class(obj) container_of(obj, struct class, subsys.kobj)
 
 static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
 			       char *buf)
 {
 	struct class_attribute *class_attr = to_class_attr(attr);
-	struct class *dc = to_class(kobj);
+	struct class_private *cp = to_class(kobj);
 	ssize_t ret = -EIO;
 
 	if (class_attr->show)
-		ret = class_attr->show(dc, buf);
+		ret = class_attr->show(cp->class, buf);
 	return ret;
 }
 
@@ -39,17 +38,18 @@ static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr,
 				const char *buf, size_t count)
 {
 	struct class_attribute *class_attr = to_class_attr(attr);
-	struct class *dc = to_class(kobj);
+	struct class_private *cp = to_class(kobj);
 	ssize_t ret = -EIO;
 
 	if (class_attr->store)
-		ret = class_attr->store(dc, buf, count);
+		ret = class_attr->store(cp->class, buf, count);
 	return ret;
 }
 
 static void class_release(struct kobject *kobj)
 {
-	struct class *class = to_class(kobj);
+	struct class_private *cp = to_class(kobj);
+	struct class *class = cp->class;
 
 	pr_debug("class '%s': release.\n", class->name);
 
@@ -78,7 +78,7 @@ int class_create_file(struct class *cls, const struct class_attribute *attr)
 {
 	int error;
 	if (cls)
-		error = sysfs_create_file(&cls->subsys.kobj, &attr->attr);
+		error = sysfs_create_file(&cls->p->subsys.kobj, &attr->attr);
 	else
 		error = -EINVAL;
 	return error;
@@ -87,21 +87,20 @@ int class_create_file(struct class *cls, const struct class_attribute *attr)
 void class_remove_file(struct class *cls, const struct class_attribute *attr)
 {
 	if (cls)
-		sysfs_remove_file(&cls->subsys.kobj, &attr->attr);
+		sysfs_remove_file(&cls->p->subsys.kobj, &attr->attr);
 }
 
 static struct class *class_get(struct class *cls)
 {
 	if (cls)
-		return container_of(kset_get(&cls->subsys),
-				    struct class, subsys);
-	return NULL;
+		kset_get(&cls->p->subsys);
+	return cls;
 }
 
 static void class_put(struct class *cls)
 {
 	if (cls)
-		kset_put(&cls->subsys);
+		kset_put(&cls->p->subsys);
 }
 
 static int add_class_attrs(struct class *cls)
@@ -136,17 +135,23 @@ static void remove_class_attrs(struct class *cls)
 
 int class_register(struct class *cls)
 {
+	struct class_private *cp;
 	int error;
 
 	pr_debug("device class '%s': registering\n", cls->name);
 
-	INIT_LIST_HEAD(&cls->devices);
-	INIT_LIST_HEAD(&cls->interfaces);
-	kset_init(&cls->class_dirs);
-	init_MUTEX(&cls->sem);
-	error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name);
-	if (error)
+	cp = kzalloc(sizeof(*cp), GFP_KERNEL);
+	if (!cp)
+		return -ENOMEM;
+	INIT_LIST_HEAD(&cp->devices);
+	INIT_LIST_HEAD(&cp->interfaces);
+	kset_init(&cp->class_dirs);
+	init_MUTEX(&cp->sem);
+	error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
+	if (error) {
+		kfree(cp);
 		return error;
+	}
 
 	/* set the default /sys/dev directory for devices of this class */
 	if (!cls->dev_kobj)
@@ -155,17 +160,21 @@ int class_register(struct class *cls)
 #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK)
 	/* let the block class directory show up in the root of sysfs */
 	if (cls != &block_class)
-		cls->subsys.kobj.kset = class_kset;
+		cp->subsys.kobj.kset = class_kset;
 #else
-	cls->subsys.kobj.kset = class_kset;
+	cp->subsys.kobj.kset = class_kset;
 #endif
-	cls->subsys.kobj.ktype = &class_ktype;
+	cp->subsys.kobj.ktype = &class_ktype;
+	cp->class = cls;
+	cls->p = cp;
 
-	error = kset_register(&cls->subsys);
-	if (!error) {
-		error = add_class_attrs(class_get(cls));
-		class_put(cls);
+	error = kset_register(&cp->subsys);
+	if (error) {
+		kfree(cp);
+		return error;
 	}
+	error = add_class_attrs(class_get(cls));
+	class_put(cls);
 	return error;
 }
 
@@ -173,7 +182,7 @@ void class_unregister(struct class *cls)
 {
 	pr_debug("device class '%s': unregistering\n", cls->name);
 	remove_class_attrs(cls);
-	kset_unregister(&cls->subsys);
+	kset_unregister(&cls->p->subsys);
 }
 
 static void class_create_release(struct class *cls)
@@ -280,8 +289,8 @@ int class_for_each_device(struct class *class, struct device *start,
 
 	if (!class)
 		return -EINVAL;
-	down(&class->sem);
-	list_for_each_entry(dev, &class->devices, node) {
+	down(&class->p->sem);
+	list_for_each_entry(dev, &class->p->devices, node) {
 		if (start) {
 			if (start == dev)
 				start = NULL;
@@ -293,7 +302,7 @@ int class_for_each_device(struct class *class, struct device *start,
 		if (error)
 			break;
 	}
-	up(&class->sem);
+	up(&class->p->sem);
 
 	return error;
 }
@@ -330,8 +339,8 @@ struct device *class_find_device(struct class *class, struct device *start,
 	if (!class)
 		return NULL;
 
-	down(&class->sem);
-	list_for_each_entry(dev, &class->devices, node) {
+	down(&class->p->sem);
+	list_for_each_entry(dev, &class->p->devices, node) {
 		if (start) {
 			if (start == dev)
 				start = NULL;
@@ -344,7 +353,7 @@ struct device *class_find_device(struct class *class, struct device *start,
 		} else
 			put_device(dev);
 	}
-	up(&class->sem);
+	up(&class->p->sem);
 
 	return found ? dev : NULL;
 }
@@ -362,13 +371,13 @@ int class_interface_register(struct class_interface *class_intf)
 	if (!parent)
 		return -EINVAL;
 
-	down(&parent->sem);
-	list_add_tail(&class_intf->node, &parent->interfaces);
+	down(&parent->p->sem);
+	list_add_tail(&class_intf->node, &parent->p->interfaces);
 	if (class_intf->add_dev) {
-		list_for_each_entry(dev, &parent->devices, node)
+		list_for_each_entry(dev, &parent->p->devices, node)
 			class_intf->add_dev(dev, class_intf);
 	}
-	up(&parent->sem);
+	up(&parent->p->sem);
 
 	return 0;
 }
@@ -381,13 +390,13 @@ void class_interface_unregister(struct class_interface *class_intf)
 	if (!parent)
 		return;
 
-	down(&parent->sem);
+	down(&parent->p->sem);
 	list_del_init(&class_intf->node);
 	if (class_intf->remove_dev) {
-		list_for_each_entry(dev, &parent->devices, node)
+		list_for_each_entry(dev, &parent->p->devices, node)
 			class_intf->remove_dev(dev, class_intf);
 	}
-	up(&parent->sem);
+	up(&parent->p->sem);
 
 	class_put(parent);
 }
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 9f05de6..64c150b 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -551,7 +551,7 @@ static struct kobject *get_device_parent(struct device *dev,
 {
 	/* class devices without a parent live in /sys/class/<classname>/ */
 	if (dev->class && (!parent || parent->class != dev->class))
-		return &dev->class->subsys.kobj;
+		return &dev->class->p->subsys.kobj;
 	/* all other devices keep their parent */
 	else if (parent)
 		return &parent->kobj;
@@ -597,13 +597,13 @@ static struct kobject *get_device_parent(struct device *dev,
 			parent_kobj = &parent->kobj;
 
 		/* find our class-directory at the parent and reference it */
-		spin_lock(&dev->class->class_dirs.list_lock);
-		list_for_each_entry(k, &dev->class->class_dirs.list, entry)
+		spin_lock(&dev->class->p->class_dirs.list_lock);
+		list_for_each_entry(k, &dev->class->p->class_dirs.list, entry)
 			if (k->parent == parent_kobj) {
 				kobj = kobject_get(k);
 				break;
 			}
-		spin_unlock(&dev->class->class_dirs.list_lock);
+		spin_unlock(&dev->class->p->class_dirs.list_lock);
 		if (kobj)
 			return kobj;
 
@@ -611,7 +611,7 @@ static struct kobject *get_device_parent(struct device *dev,
 		k = kobject_create();
 		if (!k)
 			return NULL;
-		k->kset = &dev->class->class_dirs;
+		k->kset = &dev->class->p->class_dirs;
 		retval = kobject_add(k, parent_kobj, "%s", dev->class->name);
 		if (retval < 0) {
 			kobject_put(k);
@@ -630,7 +630,7 @@ static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
 {
 	/* see if we live in a "glue" directory */
 	if (!glue_dir || !dev->class ||
-	    glue_dir->kset != &dev->class->class_dirs)
+	    glue_dir->kset != &dev->class->p->class_dirs)
 		return;
 
 	kobject_put(glue_dir);
@@ -657,17 +657,17 @@ static int device_add_class_symlinks(struct device *dev)
 	if (!dev->class)
 		return 0;
 
-	error = sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
+	error = sysfs_create_link(&dev->kobj, &dev->class->p->subsys.kobj,
 				  "subsystem");
 	if (error)
 		goto out;
 
 #ifdef CONFIG_SYSFS_DEPRECATED
 	/* stacked class devices need a symlink in the class directory */
-	if (dev->kobj.parent != &dev->class->subsys.kobj &&
+	if (dev->kobj.parent != &dev->class->p->subsys.kobj &&
 	    device_is_not_partition(dev)) {
-		error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
-					  dev->bus_id);
+		error = sysfs_create_link(&dev->class->p->subsys.kobj,
+					  &dev->kobj, dev->bus_id);
 		if (error)
 			goto out_subsys;
 	}
@@ -704,12 +704,12 @@ out_device:
 	if (dev->parent && device_is_not_partition(dev))
 		sysfs_remove_link(&dev->kobj, "device");
 out_busid:
-	if (dev->kobj.parent != &dev->class->subsys.kobj &&
+	if (dev->kobj.parent != &dev->class->p->subsys.kobj &&
 	    device_is_not_partition(dev))
-		sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
+		sysfs_remove_link(&dev->class->p->subsys.kobj, dev->bus_id);
 #else
 	/* link in the class directory pointing to the device */
-	error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
+	error = sysfs_create_link(&dev->class->p->subsys.kobj, &dev->kobj,
 				  dev->bus_id);
 	if (error)
 		goto out_subsys;
@@ -723,7 +723,7 @@ out_busid:
 	return 0;
 
 out_busid:
-	sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
+	sysfs_remove_link(&dev->class->p->subsys.kobj, dev->bus_id);
 #endif
 
 out_subsys:
@@ -749,14 +749,14 @@ static void device_remove_class_symlinks(struct device *dev)
 		sysfs_remove_link(&dev->kobj, "device");
 	}
 
-	if (dev->kobj.parent != &dev->class->subsys.kobj &&
+	if (dev->kobj.parent != &dev->class->p->subsys.kobj &&
 	    device_is_not_partition(dev))
-		sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
+		sysfs_remove_link(&dev->class->p->subsys.kobj, dev->bus_id);
 #else
 	if (dev->parent && device_is_not_partition(dev))
 		sysfs_remove_link(&dev->kobj, "device");
 
-	sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
+	sysfs_remove_link(&dev->class->p->subsys.kobj, dev->bus_id);
 #endif
 
 	sysfs_remove_link(&dev->kobj, "subsystem");
@@ -904,15 +904,16 @@ int device_add(struct device *dev)
 		klist_add_tail(&dev->knode_parent, &parent->klist_children);
 
 	if (dev->class) {
-		down(&dev->class->sem);
+		down(&dev->class->p->sem);
 		/* tie the class to the device */
-		list_add_tail(&dev->node, &dev->class->devices);
+		list_add_tail(&dev->node, &dev->class->p->devices);
 
 		/* notify any interfaces that the device is here */
-		list_for_each_entry(class_intf, &dev->class->interfaces, node)
+		list_for_each_entry(class_intf, &dev->class->p->interfaces,
+				    node)
 			if (class_intf->add_dev)
 				class_intf->add_dev(dev, class_intf);
-		up(&dev->class->sem);
+		up(&dev->class->p->sem);
 	}
  Done:
 	put_device(dev);
@@ -1013,14 +1014,15 @@ void device_del(struct device *dev)
 	if (dev->class) {
 		device_remove_class_symlinks(dev);
 
-		down(&dev->class->sem);
+		down(&dev->class->p->sem);
 		/* notify any interfaces that the device is now gone */
-		list_for_each_entry(class_intf, &dev->class->interfaces, node)
+		list_for_each_entry(class_intf, &dev->class->p->interfaces,
+				    node)
 			if (class_intf->remove_dev)
 				class_intf->remove_dev(dev, class_intf);
 		/* remove the device from the class list */
 		list_del_init(&dev->node);
-		up(&dev->class->sem);
+		up(&dev->class->p->sem);
 	}
 	device_remove_file(dev, &uevent_attr);
 	device_remove_attrs(dev);
@@ -1348,11 +1350,12 @@ int device_rename(struct device *dev, char *new_name)
 	}
 #else
 	if (dev->class) {
-		error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
-					  dev->bus_id);
+		error = sysfs_create_link(&dev->class->p->subsys.kobj,
+					  &dev->kobj, dev->bus_id);
 		if (error)
 			goto out;
-		sysfs_remove_link(&dev->class->subsys.kobj, old_device_name);
+		sysfs_remove_link(&dev->class->p->subsys.kobj,
+				  old_device_name);
 	}
 #endif
 
diff --git a/include/linux/device.h b/include/linux/device.h
index c1f7298..b055608 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -35,6 +35,7 @@ struct device;
 struct device_driver;
 struct driver_private;
 struct class;
+struct class_private;
 struct bus_type;
 struct bus_type_private;
 
@@ -186,11 +187,6 @@ struct class {
 	const char		*name;
 	struct module		*owner;
 
-	struct kset		subsys;
-	struct list_head	devices;
-	struct list_head	interfaces;
-	struct kset		class_dirs;
-	struct semaphore	sem; /* locks children, devices, interfaces */
 	struct class_attribute		*class_attrs;
 	struct device_attribute		*dev_attrs;
 	struct kobject			*dev_kobj;
@@ -204,6 +200,7 @@ struct class {
 	int (*resume)(struct device *dev);
 
 	struct pm_ops *pm;
+	struct class_private *p;
 };
 
 extern struct kobject *sysfs_dev_block_kobj;