fedora core 6 1.2949 + vserver 2.2.0
[linux-2.6.git] / drivers / base / bus.c
index 3da2405..472810f 100644 (file)
@@ -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);