/* * bus.c - bus driver management * * Copyright (c) 2002-3 Patrick Mochel * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> * Copyright (c) 2007 Novell Inc. * * This file is released under the GPLv2 * */ #include <linux/device.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/string.h> #include "base.h" #include "power/power.h" #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr) #define to_bus(obj) container_of(obj, struct bus_type_private, subsys.kobj) /* * sysfs bindings for drivers */ #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr) static int __must_check bus_rescan_devices_helper(struct device *dev, void *data); static struct bus_type *bus_get(struct bus_type *bus) { if (bus) { kset_get(&bus->p->subsys); return bus; } return NULL; } static void bus_put(struct bus_type *bus) { if (bus) kset_put(&bus->p->subsys); } static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct driver_attribute *drv_attr = to_drv_attr(attr); struct driver_private *drv_priv = to_driver(kobj); ssize_t ret = -EIO; if (drv_attr->show) ret = drv_attr->show(drv_priv->driver, buf); return ret; } static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct driver_attribute *drv_attr = to_drv_attr(attr); struct driver_private *drv_priv = to_driver(kobj); ssize_t ret = -EIO; if (drv_attr->store) ret = drv_attr->store(drv_priv->driver, buf, count); return ret; } static struct sysfs_ops driver_sysfs_ops = { .show = drv_attr_show, .store = drv_attr_store, }; static void driver_release(struct kobject *kobj) { struct driver_private *drv_priv = to_driver(kobj); pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__); kfree(drv_priv); } static struct kobj_type driver_ktype = { .sysfs_ops = &driver_sysfs_ops, .release = driver_release, }; /* * sysfs bindings for buses */ static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { struct bus_attribute *bus_attr = to_bus_attr(attr); struct bus_type_private *bus_priv = to_bus(kobj); ssize_t ret = 0; if (bus_attr->show) ret = bus_attr->show(bus_priv->bus, buf); return ret; } static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { struct bus_attribute *bus_attr = to_bus_attr(attr); struct bus_type_private *bus_priv = to_bus(kobj); ssize_t ret = 0; if (bus_attr->store) ret = bus_attr->store(bus_priv->bus, buf, count); return ret; } static struct sysfs_ops bus_sysfs_ops = { .show = bus_attr_show, .store = bus_attr_store, }; int bus_create_file(struct bus_type *bus, struct bus_attribute *attr) { int error; if (bus_get(bus)) { error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr); bus_put(bus); } else error = -EINVAL; return error; } EXPORT_SYMBOL_GPL(bus_create_file); void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr) { if (bus_get(bus)) { sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr); bus_put(bus); } } EXPORT_SYMBOL_GPL(bus_remove_file); static struct kobj_type bus_ktype = { .sysfs_ops = &bus_sysfs_ops, }; static int bus_uevent_filter(struct kset *kset, struct kobject *kobj) { struct kobj_type *ktype = get_ktype(kobj); if (ktype == &bus_ktype) return 1; return 0; } static struct kset_uevent_ops bus_uevent_ops = { .filter = bus_uevent_filter, }; static struct kset *bus_kset; #ifdef CONFIG_HOTPLUG /* Manually detach a device from its associated driver. */ static ssize_t driver_unbind(struct device_driver *drv, const char *buf, size_t count) { struct bus_type *bus = bus_get(drv->bus); struct device *dev; int err = -ENODEV; dev = bus_find_device_by_name(bus, NULL, buf); 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); bus_put(bus); return err; } static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind); /* * 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 bus_type *bus = bus_get(drv->bus); struct device *dev; int err = -ENODEV; dev = bus_find_device_by_name(bus, NULL, buf); if (dev && dev->driver == NULL && driver_match_device(drv, dev)) { 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); bus_put(bus); return err; } static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind); static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf) { return sprintf(buf, "%d\n", bus->p->drivers_autoprobe); } static ssize_t store_drivers_autoprobe(struct bus_type *bus, const char *buf, size_t count) { if (buf[0] == '0') bus->p->drivers_autoprobe = 0; else bus->p->drivers_autoprobe = 1; return count; } static ssize_t store_drivers_probe(struct bus_type *bus, const char *buf, size_t count) { struct device *dev; dev = bus_find_device_by_name(bus, NULL, buf); if (!dev) return -ENODEV; if (bus_rescan_devices_helper(dev, NULL) != 0) return -EINVAL; return count; } #endif static struct device *next_device(struct klist_iter *i) { struct klist_node *n = klist_next(i); struct device *dev = NULL; struct device_private *dev_prv; if (n) { dev_prv = to_device_private_bus(n); dev = dev_prv->device; } return dev; } /** * bus_for_each_dev - device iterator. * @bus: bus type. * @start: device to start iterating from. * @data: data for the callback. * @fn: function to be called for each device. * * Iterate over @bus's list of devices, and call @fn for each, * passing it @data. If @start is not NULL, we use that device to * begin iterating from. * * We check the return of @fn each time. If it returns anything * other than 0, we break out and return that value. * * NOTE: The device that returns a non-zero value is not retained * in any way, nor is its refcount incremented. If the caller needs * to retain this data, it should do, and increment the reference * count in the supplied callback. */ int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data, int (*fn)(struct device *, void *)) { struct klist_iter i; struct device *dev; int error = 0; if (!bus) return -EINVAL; klist_iter_init_node(&bus->p->klist_devices, &i, (start ? &start->p->knode_bus : NULL)); while ((dev = next_device(&i)) && !error) error = fn(dev, data); klist_iter_exit(&i); return error; } EXPORT_SYMBOL_GPL(bus_for_each_dev); /** * 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 *dev, void *data)) { struct klist_iter i; struct device *dev; if (!bus) return NULL; klist_iter_init_node(&bus->p->klist_devices, &i, (start ? &start->p->knode_bus : NULL)); while ((dev = next_device(&i))) if (match(dev, data) && get_device(dev)) break; klist_iter_exit(&i); return dev; } EXPORT_SYMBOL_GPL(bus_find_device); static int match_name(struct device *dev, void *data) { const char *name = data; return sysfs_streq(name, dev_name(dev)); } /** * bus_find_device_by_name - device iterator for locating a particular device of a specific name * @bus: bus type * @start: Device to begin with * @name: name of the device to match * * This is similar to the bus_find_device() function above, but it handles * searching by a name automatically, no need to write another strcmp matching * function. */ struct device *bus_find_device_by_name(struct bus_type *bus, struct device *start, const char *name) { return bus_find_device(bus, start, (void *)name, match_name); } EXPORT_SYMBOL_GPL(bus_find_device_by_name); static struct device_driver *next_driver(struct klist_iter *i) { struct klist_node *n = klist_next(i); struct driver_private *drv_priv; if (n) { drv_priv = container_of(n, struct driver_private, knode_bus); return drv_priv->driver; } return NULL; } /** * bus_for_each_drv - driver iterator * @bus: bus we're dealing with. * @start: driver to start iterating on. * @data: data to pass to the callback. * @fn: function to call for each driver. * * This is nearly identical to the device iterator above. * We iterate over each driver that belongs to @bus, and call * @fn for each. If @fn returns anything but 0, we break out * and return it. If @start is not NULL, we use it as the head * of the list. * * NOTE: we don't return the driver that returns a non-zero * value, nor do we leave the reference count incremented for that * driver. If the caller needs to know that info, it must set it * in the callback. It must also be sure to increment the refcount * so it doesn't disappear before returning to the caller. */ int bus_for_each_drv(struct bus_type *bus, struct device_driver *start, void *data, int (*fn)(struct device_driver *, void *)) { struct klist_iter i; struct device_driver *drv; int error = 0; if (!bus) return -EINVAL; klist_iter_init_node(&bus->p->klist_drivers, &i, start ? &start->p->knode_bus : NULL); while ((drv = next_driver(&i)) && !error) error = fn(drv, data); klist_iter_exit(&i); return error; } EXPORT_SYMBOL_GPL(bus_for_each_drv); static int device_add_attrs(struct bus_type *bus, struct device *dev) { int error = 0; int i; if (!bus->dev_attrs) return 0; for (i = 0; attr_name(bus->dev_attrs[i]); i++) { error = device_create_file(dev, &bus->dev_attrs[i]); if (error) { while (--i >= 0) device_remove_file(dev, &bus->dev_attrs[i]); break; } } return error; } static void device_remove_attrs(struct bus_type *bus, struct device *dev) { int i; if (bus->dev_attrs) { for (i = 0; attr_name(bus->dev_attrs[i]); i++) device_remove_file(dev, &bus->dev_attrs[i]); } } #ifdef CONFIG_SYSFS_DEPRECATED static int make_deprecated_bus_links(struct device *dev) { return sysfs_create_link(&dev->kobj, &dev->bus->p->subsys.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. * - Create link to device's bus. */ int bus_add_device(struct device *dev) { struct bus_type *bus = bus_get(dev->bus); int error = 0; if (bus) { pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev)); error = device_add_attrs(bus, dev); if (error) goto out_put; error = sysfs_create_link(&bus->p->devices_kset->kobj, &dev->kobj, dev_name(dev)); if (error) goto out_id; error = sysfs_create_link(&dev->kobj, &dev->bus->p->subsys.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->p->devices_kset->kobj, dev_name(dev)); out_id: device_remove_attrs(bus, dev); out_put: bus_put(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. */ void bus_attach_device(struct device *dev) { struct bus_type *bus = dev->bus; int ret = 0; if (bus) { if (bus->p->drivers_autoprobe) ret = device_attach(dev); WARN_ON(ret < 0); if (ret >= 0) klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices); } } /** * bus_remove_device - remove device from bus * @dev: device to be removed * * - Remove symlink from bus's directory. * - Delete device from bus's list. * - Detach from its driver. * - Drop reference taken in bus_add_device(). */ 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->p->devices_kset->kobj, dev_name(dev)); device_remove_attrs(dev->bus, dev); if (klist_node_attached(&dev->p->knode_bus)) klist_del(&dev->p->knode_bus); pr_debug("bus: '%s': remove device %s\n", dev->bus->name, dev_name(dev)); device_release_driver(dev); bus_put(dev->bus); } } static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv) { int error = 0; int i; if (bus->drv_attrs) { for (i = 0; attr_name(bus->drv_attrs[i]); i++) { error = driver_create_file(drv, &bus->drv_attrs[i]); if (error) goto err; } } done: return error; err: while (--i >= 0) driver_remove_file(drv, &bus->drv_attrs[i]); goto done; } static void driver_remove_attrs(struct bus_type *bus, struct device_driver *drv) { int i; if (bus->drv_attrs) { for (i = 0; attr_name(bus->drv_attrs[i]); i++) driver_remove_file(drv, &bus->drv_attrs[i]); } } #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); } static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe); static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO, show_drivers_autoprobe, store_drivers_autoprobe); static int add_probe_files(struct bus_type *bus) { int retval; retval = bus_create_file(bus, &bus_attr_drivers_probe); if (retval) goto out; retval = bus_create_file(bus, &bus_attr_drivers_autoprobe); if (retval) bus_remove_file(bus, &bus_attr_drivers_probe); out: return retval; } static void remove_probe_files(struct bus_type *bus) { bus_remove_file(bus, &bus_attr_drivers_autoprobe); bus_remove_file(bus, &bus_attr_drivers_probe); } #else static inline int add_bind_files(struct device_driver *drv) { return 0; } static inline void remove_bind_files(struct device_driver *drv) {} static inline int add_probe_files(struct bus_type *bus) { return 0; } static inline void remove_probe_files(struct bus_type *bus) {} #endif static ssize_t driver_uevent_store(struct device_driver *drv, const char *buf, size_t count) { enum kobject_action action; if (kobject_action_type(buf, count, &action) == 0) kobject_uevent(&drv->p->kobj, action); return count; } static DRIVER_ATTR(uevent, S_IWUSR, NULL, driver_uevent_store); /** * bus_add_driver - Add a driver to the bus. * @drv: driver. */ int bus_add_driver(struct device_driver *drv) { struct bus_type *bus; struct driver_private *priv; int error = 0; bus = bus_get(drv->bus); if (!bus) return -EINVAL; pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name); priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) { error = -ENOMEM; goto out_put_bus; } klist_init(&priv->klist_devices, NULL, NULL); priv->driver = drv; drv->p = priv; priv->kobj.kset = bus->p->drivers_kset; error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL, "%s", drv->name); if (error) goto out_unregister; if (drv->bus->p->drivers_autoprobe) { error = driver_attach(drv); if (error) goto out_unregister; } klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers); module_add_driver(drv->owner, drv); error = driver_create_file(drv, &driver_attr_uevent); if (error) { printk(KERN_ERR "%s: uevent attr (%s) failed\n", __func__, drv->name); } 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", __func__, drv->name); } error = add_bind_files(drv); if (error) { /* Ditto */ printk(KERN_ERR "%s: add_bind_files(%s) failed\n", __func__, drv->name); } kobject_uevent(&priv->kobj, KOBJ_ADD); return error; out_unregister: kobject_put(&priv->kobj); out_put_bus: bus_put(bus); return error; } /** * bus_remove_driver - delete driver from bus's knowledge. * @drv: driver. * * Detach the driver from the devices it controls, and remove * it from its bus's list of drivers. Finally, we drop the reference * to the bus we took in bus_add_driver(). */ void bus_remove_driver(struct device_driver *drv) { if (!drv->bus) return; remove_bind_files(drv); driver_remove_attrs(drv->bus, drv); driver_remove_file(drv, &driver_attr_uevent); klist_remove(&drv->p->knode_bus); pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name); driver_detach(drv); module_remove_driver(drv); kobject_put(&drv->p->kobj); bus_put(drv->bus); } /* Helper for bus_rescan_devices's iter */ 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); } return ret < 0 ? ret : 0; } /** * 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 by calling device_attach() for the unbound devices. */ int bus_rescan_devices(struct bus_type *bus) { return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper); } EXPORT_SYMBOL_GPL(bus_rescan_devices); /** * 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); /** * find_bus - locate bus by name. * @name: name of bus. * * Call kset_find_obj() to iterate over list of buses to * find a bus by name. Return bus if found. * * 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_kset, name); return k ? to_bus(k) : NULL; } #endif /* 0 */ /** * bus_add_attrs - Add default attributes for this bus. * @bus: Bus that has just been registered. */ static int bus_add_attrs(struct bus_type *bus) { int error = 0; int i; if (bus->bus_attrs) { for (i = 0; attr_name(bus->bus_attrs[i]); i++) { error = bus_create_file(bus, &bus->bus_attrs[i]); if (error) goto err; } } done: return error; err: while (--i >= 0) bus_remove_file(bus, &bus->bus_attrs[i]); goto done; } static void bus_remove_attrs(struct bus_type *bus) { int i; if (bus->bus_attrs) { for (i = 0; attr_name(bus->bus_attrs[i]); i++) bus_remove_file(bus, &bus->bus_attrs[i]); } } static void klist_devices_get(struct klist_node *n) { struct device_private *dev_prv = to_device_private_bus(n); struct device *dev = dev_prv->device; get_device(dev); } static void klist_devices_put(struct klist_node *n) { struct device_private *dev_prv = to_device_private_bus(n); struct device *dev = dev_prv->device; put_device(dev); } static ssize_t bus_uevent_store(struct bus_type *bus, const char *buf, size_t count) { enum kobject_action action; if (kobject_action_type(buf, count, &action) == 0) kobject_uevent(&bus->p->subsys.kobj, action); return count; } static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store); /** * bus_register - register a bus with the system. * @bus: bus. * * Once we have that, we registered the bus with the kobject * infrastructure, then register the children subsystems it has: * the devices and drivers that belong to the bus. */ int bus_register(struct bus_type *bus) { int retval; struct bus_type_private *priv; priv = kzalloc(sizeof(struct bus_type_private), GFP_KERNEL); if (!priv) return -ENOMEM; priv->bus = bus; bus->p = priv; BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier); retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name); if (retval) goto out; priv->subsys.kobj.kset = bus_kset; priv->subsys.kobj.ktype = &bus_ktype; priv->drivers_autoprobe = 1; retval = kset_register(&priv->subsys); if (retval) goto out; retval = bus_create_file(bus, &bus_attr_uevent); if (retval) goto bus_uevent_fail; priv->devices_kset = kset_create_and_add("devices", NULL, &priv->subsys.kobj); if (!priv->devices_kset) { retval = -ENOMEM; goto bus_devices_fail; } priv->drivers_kset = kset_create_and_add("drivers", NULL, &priv->subsys.kobj); if (!priv->drivers_kset) { retval = -ENOMEM; goto bus_drivers_fail; } klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put); klist_init(&priv->klist_drivers, NULL, NULL); retval = add_probe_files(bus); if (retval) goto bus_probe_files_fail; retval = bus_add_attrs(bus); if (retval) goto bus_attrs_fail; pr_debug("bus: '%s': registered\n", bus->name); return 0; bus_attrs_fail: remove_probe_files(bus); bus_probe_files_fail: kset_unregister(bus->p->drivers_kset); bus_drivers_fail: kset_unregister(bus->p->devices_kset); bus_devices_fail: bus_remove_file(bus, &bus_attr_uevent); bus_uevent_fail: kset_unregister(&bus->p->subsys); kfree(bus->p); out: bus->p = NULL; return retval; } EXPORT_SYMBOL_GPL(bus_register); /** * bus_unregister - remove a bus from the system * @bus: bus. * * Unregister the child subsystems and the bus itself. * Finally, we call bus_put() to release the refcount */ void bus_unregister(struct bus_type *bus) { pr_debug("bus: '%s': unregistering\n", bus->name); bus_remove_attrs(bus); remove_probe_files(bus); kset_unregister(bus->p->drivers_kset); kset_unregister(bus->p->devices_kset); bus_remove_file(bus, &bus_attr_uevent); kset_unregister(&bus->p->subsys); kfree(bus->p); bus->p = NULL; } EXPORT_SYMBOL_GPL(bus_unregister); int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb) { return blocking_notifier_chain_register(&bus->p->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->p->bus_notifier, nb); } EXPORT_SYMBOL_GPL(bus_unregister_notifier); struct kset *bus_get_kset(struct bus_type *bus) { return &bus->p->subsys; } EXPORT_SYMBOL_GPL(bus_get_kset); struct klist *bus_get_device_klist(struct bus_type *bus) { return &bus->p->klist_devices; } EXPORT_SYMBOL_GPL(bus_get_device_klist); /* * Yes, this forcably breaks the klist abstraction temporarily. It * just wants to sort the klist, not change reference counts and * take/drop locks rapidly in the process. It does all this while * holding the lock for the list, so objects can't otherwise be * added/removed while we're swizzling. */ static void device_insertion_sort_klist(struct device *a, struct list_head *list, int (*compare)(const struct device *a, const struct device *b)) { struct list_head *pos; struct klist_node *n; struct device_private *dev_prv; struct device *b; list_for_each(pos, list) { n = container_of(pos, struct klist_node, n_node); dev_prv = to_device_private_bus(n); b = dev_prv->device; if (compare(a, b) <= 0) { list_move_tail(&a->p->knode_bus.n_node, &b->p->knode_bus.n_node); return; } } list_move_tail(&a->p->knode_bus.n_node, list); } void bus_sort_breadthfirst(struct bus_type *bus, int (*compare)(const struct device *a, const struct device *b)) { LIST_HEAD(sorted_devices); struct list_head *pos, *tmp; struct klist_node *n; struct device_private *dev_prv; struct device *dev; struct klist *device_klist; device_klist = bus_get_device_klist(bus); spin_lock(&device_klist->k_lock); list_for_each_safe(pos, tmp, &device_klist->k_list) { n = container_of(pos, struct klist_node, n_node); dev_prv = to_device_private_bus(n); dev = dev_prv->device; device_insertion_sort_klist(dev, &sorted_devices, compare); } list_splice(&sorted_devices, &device_klist->k_list); spin_unlock(&device_klist->k_lock); } EXPORT_SYMBOL_GPL(bus_sort_breadthfirst); int __init buses_init(void) { bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL); if (!bus_kset) return -ENOMEM; return 0; }