X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fbase%2Fbus.c;h=472810f8e6e7332f13127b31a299f5712e4ffbc9;hb=refs%2Fheads%2Fvserver;hp=3da24059bdf1f8b843a8b7676050607853265ae7;hpb=6a77f38946aaee1cd85eeec6cf4229b204c15071;p=linux-2.6.git

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 3da24059b..472810f8e 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -8,7 +8,6 @@
  *
  */
 
-#include <linux/config.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/errno.h>
@@ -17,9 +16,6 @@
 #include "base.h"
 #include "power/power.h"
 
-#define to_dev(node) container_of(node, struct device, bus_list)
-#define to_drv(node) container_of(node, struct device_driver, kobj.entry)
-
 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
 #define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)
 
@@ -36,7 +32,7 @@ drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
 {
 	struct driver_attribute * drv_attr = to_drv_attr(attr);
 	struct device_driver * drv = to_driver(kobj);
-	ssize_t ret = 0;
+	ssize_t ret = -EIO;
 
 	if (drv_attr->show)
 		ret = drv_attr->show(drv, buf);
@@ -49,7 +45,7 @@ drv_attr_store(struct kobject * kobj, struct attribute * attr,
 {
 	struct driver_attribute * drv_attr = to_drv_attr(attr);
 	struct device_driver * drv = to_driver(kobj);
-	ssize_t ret = 0;
+	ssize_t ret = -EIO;
 
 	if (drv_attr->store)
 		ret = drv_attr->store(drv, buf, count);
@@ -65,7 +61,7 @@ static struct sysfs_ops driver_sysfs_ops = {
 static void driver_release(struct kobject * kobj)
 {
 	struct device_driver * drv = to_driver(kobj);
-	up(&drv->unload_sem);
+	complete(&drv->unloaded);
 }
 
 static struct kobj_type ktype_driver = {
@@ -133,52 +129,82 @@ static struct kobj_type ktype_bus = {
 
 };
 
-decl_subsys(bus, &ktype_bus, NULL);
+static decl_subsys(bus, &ktype_bus, NULL);
+
 
-static int __bus_for_each_dev(struct bus_type *bus, struct device *start,
-			      void *data, int (*fn)(struct device *, void *))
+#ifdef CONFIG_HOTPLUG
+
+/* Manually detach a device from its associated driver. */
+static int driver_helper(struct device *dev, void *data)
 {
-	struct list_head *head;
-	struct device *dev;
-	int error = 0;
+	const char *name = data;
 
-	if (!(bus = get_bus(bus)))
-		return -EINVAL;
+	if (strcmp(name, dev->bus_id) == 0)
+		return 1;
+	return 0;
+}
 
-	head = &bus->devices.list;
-	dev = list_prepare_entry(start, head, bus_list);
-	list_for_each_entry_continue(dev, head, bus_list) {
-		get_device(dev);
-		error = fn(dev, data);
-		put_device(dev);
-		if (error)
-			break;
+static ssize_t driver_unbind(struct device_driver *drv,
+			     const char *buf, size_t count)
+{
+	struct bus_type *bus = get_bus(drv->bus);
+	struct device *dev;
+	int err = -ENODEV;
+
+	dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
+	if (dev && dev->driver == drv) {
+		if (dev->parent)	/* Needed for USB */
+			down(&dev->parent->sem);
+		device_release_driver(dev);
+		if (dev->parent)
+			up(&dev->parent->sem);
+		err = count;
 	}
+	put_device(dev);
 	put_bus(bus);
-	return error;
+	return err;
 }
+static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);
 
-static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
-			      void * data, int (*fn)(struct device_driver *, void *))
+/*
+ * Manually attach a device to a driver.
+ * Note: the driver must want to bind to the device,
+ * it is not possible to override the driver's id table.
+ */
+static ssize_t driver_bind(struct device_driver *drv,
+			   const char *buf, size_t count)
 {
-	struct list_head *head;
-	struct device_driver *drv;
-	int error = 0;
-
-	if (!(bus = get_bus(bus)))
-		return -EINVAL;
-
-	head = &bus->drivers.list;
-	drv = list_prepare_entry(start, head, kobj.entry);
-	list_for_each_entry_continue(drv, head, kobj.entry) {
-		get_driver(drv);
-		error = fn(drv, data);
-		put_driver(drv);
-		if (error)
-			break;
+	struct bus_type *bus = get_bus(drv->bus);
+	struct device *dev;
+	int err = -ENODEV;
+
+	dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
+	if (dev && dev->driver == NULL) {
+		if (dev->parent)	/* Needed for USB */
+			down(&dev->parent->sem);
+		down(&dev->sem);
+		err = driver_probe_device(drv, dev);
+		up(&dev->sem);
+		if (dev->parent)
+			up(&dev->parent->sem);
+
+		if (err > 0) 		/* success */
+			err = count;
+		else if (err == 0)	/* driver didn't accept device */
+			err = -ENODEV;
 	}
+	put_device(dev);
 	put_bus(bus);
-	return error;
+	return err;
+}
+static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
+
+#endif
+
+static struct device * next_device(struct klist_iter * i)
+{
+	struct klist_node * n = klist_next(i);
+	return n ? container_of(n, struct device, knode_bus) : NULL;
 }
 
 /**
@@ -204,12 +230,60 @@ static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
 int bus_for_each_dev(struct bus_type * bus, struct device * start,
 		     void * data, int (*fn)(struct device *, void *))
 {
-	int ret;
+	struct klist_iter i;
+	struct device * dev;
+	int error = 0;
 
-	down_read(&bus->subsys.rwsem);
-	ret = __bus_for_each_dev(bus, start, data, fn);
-	up_read(&bus->subsys.rwsem);
-	return ret;
+	if (!bus)
+		return -EINVAL;
+
+	klist_iter_init_node(&bus->klist_devices, &i,
+			     (start ? &start->knode_bus : NULL));
+	while ((dev = next_device(&i)) && !error)
+		error = fn(dev, data);
+	klist_iter_exit(&i);
+	return error;
+}
+
+/**
+ * bus_find_device - device iterator for locating a particular device.
+ * @bus: bus type
+ * @start: Device to begin with
+ * @data: Data to pass to match function
+ * @match: Callback function to check device
+ *
+ * This is similar to the bus_for_each_dev() function above, but it
+ * returns a reference to a device that is 'found' for later use, as
+ * determined by the @match callback.
+ *
+ * The callback should return 0 if the device doesn't match and non-zero
+ * if it does.  If the callback returns non-zero, this function will
+ * return to the caller and not iterate over any more devices.
+ */
+struct device * bus_find_device(struct bus_type *bus,
+				struct device *start, void *data,
+				int (*match)(struct device *, void *))
+{
+	struct klist_iter i;
+	struct device *dev;
+
+	if (!bus)
+		return NULL;
+
+	klist_iter_init_node(&bus->klist_devices, &i,
+			     (start ? &start->knode_bus : NULL));
+	while ((dev = next_device(&i)))
+		if (match(dev, data) && get_device(dev))
+			break;
+	klist_iter_exit(&i);
+	return dev;
+}
+
+
+static struct device_driver * next_driver(struct klist_iter * i)
+{
+	struct klist_node * n = klist_next(i);
+	return n ? container_of(n, struct device_driver, knode_bus) : NULL;
 }
 
 /**
@@ -235,181 +309,19 @@ int bus_for_each_dev(struct bus_type * bus, struct device * start,
 int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
 		     void * data, int (*fn)(struct device_driver *, void *))
 {
-	int ret;
-
-	down_read(&bus->subsys.rwsem);
-	ret = __bus_for_each_drv(bus, start, data, fn);
-	up_read(&bus->subsys.rwsem);
-	return ret;
-}
-
-/**
- *	device_bind_driver - bind a driver to one device.
- *	@dev:	device.
- *
- *	Allow manual attachment of a driver to a device.
- *	Caller must have already set @dev->driver.
- *
- *	Note that this does not modify the bus reference count
- *	nor take the bus's rwsem. Please verify those are accounted
- *	for before calling this. (It is ok to call with no other effort
- *	from a driver's probe() method.)
- */
-
-void device_bind_driver(struct device * dev)
-{
-	pr_debug("bound device '%s' to driver '%s'\n",
-		 dev->bus_id, dev->driver->name);
-	list_add_tail(&dev->driver_list, &dev->driver->devices);
-	sysfs_create_link(&dev->driver->kobj, &dev->kobj,
-			  kobject_name(&dev->kobj));
-	sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
-}
-
-
-/**
- *	driver_probe_device - attempt to bind device & driver.
- *	@drv:	driver.
- *	@dev:	device.
- *
- *	First, we call the bus's match function, if one present, which
- *	should compare the device IDs the driver supports with the
- *	device IDs of the device. Note we don't do this ourselves
- *	because we don't know the format of the ID structures, nor what
- *	is to be considered a match and what is not.
- *
- *	If we find a match, we call @drv->probe(@dev) if it exists, and
- *	call device_bind_driver() above.
- */
-int driver_probe_device(struct device_driver * drv, struct device * dev)
-{
-	if (drv->bus->match && !drv->bus->match(dev, drv))
-		return -ENODEV;
-
-	dev->driver = drv;
-	if (drv->probe) {
-		int error = drv->probe(dev);
-		if (error) {
-			dev->driver = NULL;
-			return error;
-		}
-	}
-
-	device_bind_driver(dev);
-	return 0;
-}
-
-
-/**
- *	device_attach - try to attach device to a driver.
- *	@dev:	device.
- *
- *	Walk the list of drivers that the bus has and call
- *	driver_probe_device() for each pair. If a compatible
- *	pair is found, break out and return.
- */
-int device_attach(struct device * dev)
-{
- 	struct bus_type * bus = dev->bus;
-	struct list_head * entry;
-	int error;
-
-	if (dev->driver) {
-		device_bind_driver(dev);
-		return 1;
-	}
-
-	if (bus->match) {
-		list_for_each(entry, &bus->drivers.list) {
-			struct device_driver * drv = to_drv(entry);
-			error = driver_probe_device(drv, dev);
-			if (!error)
-				/* success, driver matched */
-				return 1;
-			if (error != -ENODEV && error != -ENXIO)
-				/* driver matched but the probe failed */
-				printk(KERN_WARNING
-				    "%s: probe of %s failed with error %d\n",
-				    drv->name, dev->bus_id, error);
-		}
-	}
-
-	return 0;
-}
-
-
-/**
- *	driver_attach - try to bind driver to devices.
- *	@drv:	driver.
- *
- *	Walk the list of devices that the bus has on it and try to
- *	match the driver with each one.  If driver_probe_device()
- *	returns 0 and the @dev->driver is set, we've found a
- *	compatible pair.
- *
- *	Note that we ignore the -ENODEV error from driver_probe_device(),
- *	since it's perfectly valid for a driver not to bind to any devices.
- */
-void driver_attach(struct device_driver * drv)
-{
-	struct bus_type * bus = drv->bus;
-	struct list_head * entry;
-	int error;
-
-	if (!bus->match)
-		return;
-
-	list_for_each(entry, &bus->devices.list) {
-		struct device * dev = container_of(entry, struct device, bus_list);
-		if (!dev->driver) {
-			error = driver_probe_device(drv, dev);
-			if (error && (error != -ENODEV))
-				/* driver matched but the probe failed */
-				printk(KERN_WARNING
-				    "%s: probe of %s failed with error %d\n",
-				    drv->name, dev->bus_id, error);
-		}
-	}
-}
-
-
-/**
- *	device_release_driver - manually detach device from driver.
- *	@dev:	device.
- *
- *	Manually detach device from driver.
- *	Note that this is called without incrementing the bus
- *	reference count nor taking the bus's rwsem. Be sure that
- *	those are accounted for before calling this function.
- */
-
-void device_release_driver(struct device * dev)
-{
-	struct device_driver * drv = dev->driver;
-	if (drv) {
-		sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
-		sysfs_remove_link(&dev->kobj, "driver");
-		list_del_init(&dev->driver_list);
-		device_detach_shutdown(dev);
-		if (drv->remove)
-			drv->remove(dev);
-		dev->driver = NULL;
-	}
-}
-
+	struct klist_iter i;
+	struct device_driver * drv;
+	int error = 0;
 
-/**
- *	driver_detach - detach driver from all devices it controls.
- *	@drv:	driver.
- */
+	if (!bus)
+		return -EINVAL;
 
-static void driver_detach(struct device_driver * drv)
-{
-	struct list_head * entry, * next;
-	list_for_each_safe(entry, next, &drv->devices) {
-		struct device * dev = container_of(entry, struct device, driver_list);
-		device_release_driver(dev);
-	}
+	klist_iter_init_node(&bus->klist_drivers, &i,
+			     start ? &start->knode_bus : NULL);
+	while ((drv = next_driver(&i)) && !error)
+		error = fn(drv, data);
+	klist_iter_exit(&i);
+	return error;
 }
 
 static int device_add_attrs(struct bus_type * bus, struct device * dev)
@@ -443,14 +355,28 @@ static void device_remove_attrs(struct bus_type * bus, struct device * dev)
 	}
 }
 
+#ifdef CONFIG_SYSFS_DEPRECATED
+static int make_deprecated_bus_links(struct device *dev)
+{
+	return sysfs_create_link(&dev->kobj,
+				 &dev->bus->subsys.kset.kobj, "bus");
+}
+
+static void remove_deprecated_bus_links(struct device *dev)
+{
+	sysfs_remove_link(&dev->kobj, "bus");
+}
+#else
+static inline int make_deprecated_bus_links(struct device *dev) { return 0; }
+static inline void remove_deprecated_bus_links(struct device *dev) { }
+#endif
 
 /**
  *	bus_add_device - add device to bus
  *	@dev:	device being added
  *
  *	- Add the device to its bus's list of devices.
- *	- Try to attach to driver.
- *	- Create link to device's physical location.
+ *	- Create link to device's bus.
  */
 int bus_add_device(struct device * dev)
 {
@@ -458,17 +384,59 @@ int bus_add_device(struct device * dev)
 	int error = 0;
 
 	if (bus) {
-		down_write(&dev->bus->subsys.rwsem);
 		pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id);
-		list_add_tail(&dev->bus_list, &dev->bus->devices.list);
-		device_attach(dev);
-		up_write(&dev->bus->subsys.rwsem);
-		device_add_attrs(bus, dev);
-		sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
+		error = device_add_attrs(bus, dev);
+		if (error)
+			goto out_put;
+		error = sysfs_create_link(&bus->devices.kobj,
+						&dev->kobj, dev->bus_id);
+		if (error)
+			goto out_id;
+		error = sysfs_create_link(&dev->kobj,
+				&dev->bus->subsys.kset.kobj, "subsystem");
+		if (error)
+			goto out_subsys;
+		error = make_deprecated_bus_links(dev);
+		if (error)
+			goto out_deprecated;
 	}
+	return 0;
+
+out_deprecated:
+	sysfs_remove_link(&dev->kobj, "subsystem");
+out_subsys:
+	sysfs_remove_link(&bus->devices.kobj, dev->bus_id);
+out_id:
+	device_remove_attrs(bus, dev);
+out_put:
+	put_bus(dev->bus);
 	return error;
 }
 
+/**
+ *	bus_attach_device - add device to bus
+ *	@dev:	device tried to attach to a driver
+ *
+ *	- Add device to bus's list of devices.
+ *	- Try to attach to driver.
+ */
+int bus_attach_device(struct device * dev)
+{
+	struct bus_type *bus = dev->bus;
+	int ret = 0;
+
+	if (bus) {
+		dev->is_registered = 1;
+		ret = device_attach(dev);
+		if (ret >= 0) {
+			klist_add_tail(&dev->knode_bus, &bus->klist_devices);
+			ret = 0;
+		} else
+			dev->is_registered = 0;
+	}
+	return ret;
+}
+
 /**
  *	bus_remove_device - remove device from bus
  *	@dev:	device to be removed
@@ -481,13 +449,16 @@ int bus_add_device(struct device * dev)
 void bus_remove_device(struct device * dev)
 {
 	if (dev->bus) {
+		sysfs_remove_link(&dev->kobj, "subsystem");
+		remove_deprecated_bus_links(dev);
 		sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
 		device_remove_attrs(dev->bus, dev);
-		down_write(&dev->bus->subsys.rwsem);
+		if (dev->is_registered) {
+			dev->is_registered = 0;
+			klist_del(&dev->knode_bus);
+		}
 		pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
 		device_release_driver(dev);
-		list_del_init(&dev->bus_list);
-		up_write(&dev->bus->subsys.rwsem);
 		put_bus(dev->bus);
 	}
 }
@@ -523,41 +494,82 @@ static void driver_remove_attrs(struct bus_type * bus, struct device_driver * dr
 	}
 }
 
+#ifdef CONFIG_HOTPLUG
+/*
+ * Thanks to drivers making their tables __devinit, we can't allow manual
+ * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
+ */
+static int __must_check add_bind_files(struct device_driver *drv)
+{
+	int ret;
+
+	ret = driver_create_file(drv, &driver_attr_unbind);
+	if (ret == 0) {
+		ret = driver_create_file(drv, &driver_attr_bind);
+		if (ret)
+			driver_remove_file(drv, &driver_attr_unbind);
+	}
+	return ret;
+}
+
+static void remove_bind_files(struct device_driver *drv)
+{
+	driver_remove_file(drv, &driver_attr_bind);
+	driver_remove_file(drv, &driver_attr_unbind);
+}
+#else
+static inline int add_bind_files(struct device_driver *drv) { return 0; }
+static inline void remove_bind_files(struct device_driver *drv) {}
+#endif
 
 /**
  *	bus_add_driver - Add a driver to the bus.
  *	@drv:	driver.
  *
  */
-int bus_add_driver(struct device_driver * drv)
+int bus_add_driver(struct device_driver *drv)
 {
 	struct bus_type * bus = get_bus(drv->bus);
 	int error = 0;
 
-	if (bus) {
-		pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
-		error = kobject_set_name(&drv->kobj, "%s", drv->name);
-		if (error) {
-			put_bus(bus);
-			return error;
-		}
-		drv->kobj.kset = &bus->drivers;
-		if ((error = kobject_register(&drv->kobj))) {
-			put_bus(bus);
-			return error;
-		}
-
-		down_write(&bus->subsys.rwsem);
-		driver_attach(drv);
-		up_write(&bus->subsys.rwsem);
-		module_add_driver(drv->owner, drv);
-
-		driver_add_attrs(bus, drv);
+	if (!bus)
+		return 0;
+
+	pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
+	error = kobject_set_name(&drv->kobj, "%s", drv->name);
+	if (error)
+		goto out_put_bus;
+	drv->kobj.kset = &bus->drivers;
+	if ((error = kobject_register(&drv->kobj)))
+		goto out_put_bus;
+
+	error = driver_attach(drv);
+	if (error)
+		goto out_unregister;
+	klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
+	module_add_driver(drv->owner, drv);
+
+	error = driver_add_attrs(bus, drv);
+	if (error) {
+		/* How the hell do we get out of this pickle? Give up */
+		printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
+			__FUNCTION__, drv->name);
+	}
+	error = add_bind_files(drv);
+	if (error) {
+		/* Ditto */
+		printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
+			__FUNCTION__, drv->name);
 	}
+
+	return error;
+out_unregister:
+	kobject_unregister(&drv->kobj);
+out_put_bus:
+	put_bus(bus);
 	return error;
 }
 
-
 /**
  *	bus_remove_driver - delete driver from bus's knowledge.
  *	@drv:	driver.
@@ -569,55 +581,77 @@ int bus_add_driver(struct device_driver * drv)
 
 void bus_remove_driver(struct device_driver * drv)
 {
-	if (drv->bus) {
-		driver_remove_attrs(drv->bus, drv);
-		down_write(&drv->bus->subsys.rwsem);
-		pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
-		driver_detach(drv);
-		up_write(&drv->bus->subsys.rwsem);
-		module_remove_driver(drv);
-		kobject_unregister(&drv->kobj);
-		put_bus(drv->bus);
-	}
+	if (!drv->bus)
+		return;
+
+	remove_bind_files(drv);
+	driver_remove_attrs(drv->bus, drv);
+	klist_remove(&drv->knode_bus);
+	pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
+	driver_detach(drv);
+	module_remove_driver(drv);
+	kobject_unregister(&drv->kobj);
+	put_bus(drv->bus);
 }
 
 
 /* Helper for bus_rescan_devices's iter */
-static int bus_rescan_devices_helper(struct device *dev, void *data)
-{
-	int *count = data;
-
-	if (!dev->driver && device_attach(dev))
-		(*count)++;
-
-	return 0;
+static int __must_check bus_rescan_devices_helper(struct device *dev,
+						void *data)
+{
+	int ret = 0;
+
+	if (!dev->driver) {
+		if (dev->parent)	/* Needed for USB */
+			down(&dev->parent->sem);
+		ret = device_attach(dev);
+		if (dev->parent)
+			up(&dev->parent->sem);
+		if (ret > 0)
+			ret = 0;
+	}
+	return ret < 0 ? ret : 0;
 }
 
-
 /**
- *	bus_rescan_devices - rescan devices on the bus for possible drivers
- *	@bus:	the bus to scan.
+ * bus_rescan_devices - rescan devices on the bus for possible drivers
+ * @bus: the bus to scan.
  *
- *	This function will look for devices on the bus with no driver
- *	attached and rescan it against existing drivers to see if it
- *	matches any. Calls device_attach(). Returns the number of devices
- *	that were sucessfully bound to a driver.
+ * This function will look for devices on the bus with no driver
+ * attached and rescan it against existing drivers to see if it matches
+ * any by calling device_attach() for the unbound devices.
  */
 int bus_rescan_devices(struct bus_type * bus)
 {
-	int count = 0;
-
-	down_write(&bus->subsys.rwsem);
-	__bus_for_each_dev(bus, NULL, &count, bus_rescan_devices_helper);
-	up_write(&bus->subsys.rwsem);
-
-	return count;
+	return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
 }
 
+/**
+ * device_reprobe - remove driver for a device and probe for a new driver
+ * @dev: the device to reprobe
+ *
+ * This function detaches the attached driver (if any) for the given
+ * device and restarts the driver probing process.  It is intended
+ * to use if probing criteria changed during a devices lifetime and
+ * driver attachment should change accordingly.
+ */
+int device_reprobe(struct device *dev)
+{
+	if (dev->driver) {
+		if (dev->parent)        /* Needed for USB */
+			down(&dev->parent->sem);
+		device_release_driver(dev);
+		if (dev->parent)
+			up(&dev->parent->sem);
+	}
+	return bus_rescan_devices_helper(dev, NULL);
+}
+EXPORT_SYMBOL_GPL(device_reprobe);
 
-struct bus_type * get_bus(struct bus_type * bus)
+struct bus_type *get_bus(struct bus_type *bus)
 {
-	return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL;
+	return bus ? container_of(subsys_get(&bus->subsys),
+				struct bus_type, subsys) : NULL;
 }
 
 void put_bus(struct bus_type * bus)
@@ -635,12 +669,13 @@ void put_bus(struct bus_type * bus)
  *
  *	Note that kset_find_obj increments bus' reference count.
  */
-
+#if 0
 struct bus_type * find_bus(char * name)
 {
 	struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
 	return k ? to_bus(k) : NULL;
 }
+#endif  /*  0  */
 
 
 /**
@@ -677,6 +712,20 @@ static void bus_remove_attrs(struct bus_type * bus)
 	}
 }
 
+static void klist_devices_get(struct klist_node *n)
+{
+	struct device *dev = container_of(n, struct device, knode_bus);
+
+	get_device(dev);
+}
+
+static void klist_devices_put(struct klist_node *n)
+{
+	struct device *dev = container_of(n, struct device, knode_bus);
+
+	put_device(dev);
+}
+
 /**
  *	bus_register - register a bus with the system.
  *	@bus:	bus.
@@ -689,6 +738,8 @@ int bus_register(struct bus_type * bus)
 {
 	int retval;
 
+	BLOCKING_INIT_NOTIFIER_HEAD(&bus->bus_notifier);
+
 	retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
 	if (retval)
 		goto out;
@@ -710,11 +761,18 @@ int bus_register(struct bus_type * bus)
 	retval = kset_register(&bus->drivers);
 	if (retval)
 		goto bus_drivers_fail;
-	bus_add_attrs(bus);
+
+	klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
+	klist_init(&bus->klist_drivers, NULL, NULL);
+	retval = bus_add_attrs(bus);
+	if (retval)
+		goto bus_attrs_fail;
 
 	pr_debug("bus type '%s' registered\n", bus->name);
 	return 0;
 
+bus_attrs_fail:
+	kset_unregister(&bus->drivers);
 bus_drivers_fail:
 	kset_unregister(&bus->devices);
 bus_devices_fail:
@@ -740,6 +798,18 @@ void bus_unregister(struct bus_type * bus)
 	subsystem_unregister(&bus->subsys);
 }
 
+int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&bus->bus_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bus_register_notifier);
+
+int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&bus->bus_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bus_unregister_notifier);
+
 int __init buses_init(void)
 {
 	return subsystem_register(&bus_subsys);
@@ -747,22 +817,12 @@ int __init buses_init(void)
 
 
 EXPORT_SYMBOL_GPL(bus_for_each_dev);
+EXPORT_SYMBOL_GPL(bus_find_device);
 EXPORT_SYMBOL_GPL(bus_for_each_drv);
 
-EXPORT_SYMBOL_GPL(driver_probe_device);
-EXPORT_SYMBOL_GPL(device_bind_driver);
-EXPORT_SYMBOL_GPL(device_release_driver);
-EXPORT_SYMBOL_GPL(device_attach);
-EXPORT_SYMBOL_GPL(driver_attach);
-
-EXPORT_SYMBOL_GPL(bus_add_device);
-EXPORT_SYMBOL_GPL(bus_remove_device);
 EXPORT_SYMBOL_GPL(bus_register);
 EXPORT_SYMBOL_GPL(bus_unregister);
 EXPORT_SYMBOL_GPL(bus_rescan_devices);
-EXPORT_SYMBOL_GPL(get_bus);
-EXPORT_SYMBOL_GPL(put_bus);
-EXPORT_SYMBOL_GPL(find_bus);
 
 EXPORT_SYMBOL_GPL(bus_create_file);
 EXPORT_SYMBOL_GPL(bus_remove_file);