driver core: remove fields from struct bus_type

struct bus_type is static everywhere in the kernel.  This moves the
kobject in the structure out of it, and a bunch of other private only to
the driver core fields are now moved to a private structure.  This lets
us dynamically create the backing kobject properly and gives us the
chance to be able to document to users exactly how to use the struct
bus_type as there are no fields they can improperly access.

Thanks to Kay for the build fixes on this patch.

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

drivers/base/base.h

 
-/* initialisation functions */
+/**
+ * struct bus_type_private - structure to hold the private to the driver core portions of the bus_type structure.
+ *
+ * @subsys - the struct kset that defines this bus.  This is the main kobject
+ * @drivers_kset - the list of drivers associated with this bus
+ * @devices_kset - the list of devices associated with this bus
+ * @klist_devices - the klist to iterate over the @devices_kset
+ * @klist_drivers - the klist to iterate over the @drivers_kset
+ * @bus_notifier - the bus notifier list for anything that cares about things
+ * on this bus.
+ * @bus - pointer back to the struct bus_type that this structure is associated
+ * with.
+ *
+ * This structure is the one that is the actual kobject allowing struct
+ * bus_type to be statically allocated safely.  Nothing outside of the driver
+ * core should ever touch these fields.
+ */
+struct bus_type_private {
+	struct kset subsys;
+	struct kset *drivers_kset;
+	struct kset *devices_kset;
+	struct klist klist_devices;
+	struct klist klist_drivers;
+	struct blocking_notifier_head bus_notifier;
+	unsigned int drivers_autoprobe:1;
+	struct bus_type *bus;
+};
+
 
+/* initialisation functions */
 extern int devices_init(void);
 extern int buses_init(void);
 extern int classes_init(void);

drivers/base/core.c

@@ -769,7 +769,7 @@ int device_add(struct device *dev)
 
 	/* notify clients of device entry (new way) */
 	if (dev->bus)
-		blocking_notifier_call_chain(&dev->bus->bus_notifier,
+		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_ADD_DEVICE, dev);
 
 	error = device_create_file(dev, &uevent_attr);
@@ -820,7 +820,7 @@ int device_add(struct device *dev)
 	dpm_sysfs_remove(dev);
  PMError:
 	if (dev->bus)
-		blocking_notifier_call_chain(&dev->bus->bus_notifier,
+		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_DEL_DEVICE, dev);
 	device_remove_attrs(dev);
  AttrsError:
@@ -999,7 +999,7 @@ void device_del(struct device * dev)
 	if (platform_notify_remove)
 		platform_notify_remove(dev);
 	if (dev->bus)
-		blocking_notifier_call_chain(&dev->bus->bus_notifier,
+		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_DEL_DEVICE, dev);
 	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
 	kobject_del(&dev->kobj);

drivers/base/dd.c

@@ -38,7 +38,7 @@ static void driver_bound(struct device *dev)
 		 dev->bus_id, dev->driver->name);
 
 	if (dev->bus)
-		blocking_notifier_call_chain(&dev->bus->bus_notifier,
+		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_BOUND_DRIVER, dev);
 
 	klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);
@@ -296,7 +296,7 @@ static void __device_release_driver(struct device * dev)
 		klist_remove(&dev->knode_driver);
 
 		if (dev->bus)
-			blocking_notifier_call_chain(&dev->bus->bus_notifier,
+			blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 						     BUS_NOTIFY_UNBIND_DRIVER,
 						     dev);
 

drivers/base/driver.c

@@ -185,7 +185,7 @@ void driver_unregister(struct device_driver * drv)
  */
 struct device_driver *driver_find(const char *name, struct bus_type *bus)
 {
-	struct kobject *k = kset_find_obj(bus->drivers_kset, name);
+	struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
 	if (k)
 		return to_drv(k);
 	return NULL;

drivers/base/platform.c

@@ -497,12 +497,12 @@ int __init_or_module platform_driver_probe(struct platform_driver *drv,
 	 * if the probe was successful, and make sure any forced probes of
 	 * new devices fail.
 	 */
-	spin_lock(&platform_bus_type.klist_drivers.k_lock);
+	spin_lock(&platform_bus_type.p->klist_drivers.k_lock);
 	drv->probe = NULL;
 	if (code == 0 && list_empty(&drv->driver.klist_devices.k_list))
 		retval = -ENODEV;
 	drv->driver.probe = platform_drv_probe_fail;
-	spin_unlock(&platform_bus_type.klist_drivers.k_lock);
+	spin_unlock(&platform_bus_type.p->klist_drivers.k_lock);
 
 	if (code != retval)
 		platform_driver_unregister(drv);

include/linux/device.h

@@ -35,6 +35,7 @@ struct device_driver;
 struct class;
 struct class_device;
 struct bus_type;
+struct bus_type_private;
 
 struct bus_attribute {
 	struct attribute	attr;
@@ -51,15 +52,6 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
 
 struct bus_type {
 	const char		* name;
-
-	struct kset		subsys;
-	struct kset		*drivers_kset;
-	struct kset		*devices_kset;
-	struct klist		klist_devices;
-	struct klist		klist_drivers;
-
-	struct blocking_notifier_head bus_notifier;
-
 	struct bus_attribute	* bus_attrs;
 	struct device_attribute	* dev_attrs;
 	struct driver_attribute	* drv_attrs;
@@ -75,7 +67,7 @@ struct bus_type {
 	int (*resume_early)(struct device * dev);
 	int (*resume)(struct device * dev);
 
-	unsigned int drivers_autoprobe:1;
+	struct bus_type_private *p;
 };
 
 extern int __must_check bus_register(struct bus_type * bus);