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 2c9ae43e2219..0ec372a67762 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 3918d0e432d4..06f09c929a91 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 9f05de6f80b5..64c150b5a883 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 c1f72984875f..b0556082179b 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;