2 * bus.c - bus driver management
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2007 Novell Inc.
9 * This file is released under the GPLv2
13 #include <linux/device.h>
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17 #include <linux/init.h>
18 #include <linux/string.h>
20 #include "power/power.h"
21 #include "linux/usb.h"
22 #include "devices_filter.h"
24 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
27 * sysfs bindings for drivers
30 #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
33 static int __must_check bus_rescan_devices_helper(struct device *dev,
36 static struct bus_type *bus_get(struct bus_type *bus)
39 kset_get(&bus->p->subsys);
45 static void bus_put(struct bus_type *bus)
48 kset_put(&bus->p->subsys);
51 static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
54 struct driver_attribute *drv_attr = to_drv_attr(attr);
55 struct driver_private *drv_priv = to_driver(kobj);
59 ret = drv_attr->show(drv_priv->driver, buf);
63 static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
64 const char *buf, size_t count)
66 struct driver_attribute *drv_attr = to_drv_attr(attr);
67 struct driver_private *drv_priv = to_driver(kobj);
71 ret = drv_attr->store(drv_priv->driver, buf, count);
75 static const struct sysfs_ops driver_sysfs_ops = {
76 .show = drv_attr_show,
77 .store = drv_attr_store,
80 static void driver_release(struct kobject *kobj)
82 struct driver_private *drv_priv = to_driver(kobj);
84 pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
88 static struct kobj_type driver_ktype = {
89 .sysfs_ops = &driver_sysfs_ops,
90 .release = driver_release,
94 * sysfs bindings for buses
96 static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
99 struct bus_attribute *bus_attr = to_bus_attr(attr);
100 struct subsys_private *subsys_priv = to_subsys_private(kobj);
104 ret = bus_attr->show(subsys_priv->bus, buf);
108 static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
109 const char *buf, size_t count)
111 struct bus_attribute *bus_attr = to_bus_attr(attr);
112 struct subsys_private *subsys_priv = to_subsys_private(kobj);
116 ret = bus_attr->store(subsys_priv->bus, buf, count);
120 static const struct sysfs_ops bus_sysfs_ops = {
121 .show = bus_attr_show,
122 .store = bus_attr_store,
125 int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
129 error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
135 EXPORT_SYMBOL_GPL(bus_create_file);
137 void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
140 sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
144 EXPORT_SYMBOL_GPL(bus_remove_file);
146 static struct kobj_type bus_ktype = {
147 .sysfs_ops = &bus_sysfs_ops,
150 static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
152 struct kobj_type *ktype = get_ktype(kobj);
154 if (ktype == &bus_ktype)
159 static const struct kset_uevent_ops bus_uevent_ops = {
160 .filter = bus_uevent_filter,
163 static struct kset *bus_kset;
166 #ifdef CONFIG_HOTPLUG
167 /* Manually detach a device from its associated driver. */
168 static ssize_t driver_unbind(struct device_driver *drv,
169 const char *buf, size_t count)
171 struct bus_type *bus = bus_get(drv->bus);
175 dev = bus_find_device_by_name(bus, NULL, buf);
176 if (dev && dev->driver == drv) {
177 if (dev->parent) /* Needed for USB */
178 device_lock(dev->parent);
179 device_release_driver(dev);
181 device_unlock(dev->parent);
188 static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);
191 * Manually attach a device to a driver.
192 * Note: the driver must want to bind to the device,
193 * it is not possible to override the driver's id table.
195 static ssize_t driver_bind(struct device_driver *drv,
196 const char *buf, size_t count)
198 struct bus_type *bus = bus_get(drv->bus);
202 dev = bus_find_device_by_name(bus, NULL, buf);
203 if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
204 if (dev->parent) /* Needed for USB */
205 device_lock(dev->parent);
207 err = driver_probe_device(drv, dev);
210 device_unlock(dev->parent);
215 } else if (err == 0) {
216 /* driver didn't accept device */
224 static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
226 static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
228 return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
231 static ssize_t store_drivers_autoprobe(struct bus_type *bus,
232 const char *buf, size_t count)
235 bus->p->drivers_autoprobe = 0;
237 bus->p->drivers_autoprobe = 1;
241 static ssize_t store_drivers_probe(struct bus_type *bus,
242 const char *buf, size_t count)
246 dev = bus_find_device_by_name(bus, NULL, buf);
249 if (bus_rescan_devices_helper(dev, NULL) != 0)
255 static struct device *next_device(struct klist_iter *i)
257 struct klist_node *n = klist_next(i);
258 struct device *dev = NULL;
259 struct device_private *dev_prv;
262 dev_prv = to_device_private_bus(n);
263 dev = dev_prv->device;
269 * bus_for_each_dev - device iterator.
271 * @start: device to start iterating from.
272 * @data: data for the callback.
273 * @fn: function to be called for each device.
275 * Iterate over @bus's list of devices, and call @fn for each,
276 * passing it @data. If @start is not NULL, we use that device to
277 * begin iterating from.
279 * We check the return of @fn each time. If it returns anything
280 * other than 0, we break out and return that value.
282 * NOTE: The device that returns a non-zero value is not retained
283 * in any way, nor is its refcount incremented. If the caller needs
284 * to retain this data, it should do so, and increment the reference
285 * count in the supplied callback.
287 int bus_for_each_dev(struct bus_type *bus, struct device *start,
288 void *data, int (*fn)(struct device *, void *))
297 klist_iter_init_node(&bus->p->klist_devices, &i,
298 (start ? &start->p->knode_bus : NULL));
299 while ((dev = next_device(&i)) && !error)
300 error = fn(dev, data);
304 EXPORT_SYMBOL_GPL(bus_for_each_dev);
307 * bus_find_device - device iterator for locating a particular device.
309 * @start: Device to begin with
310 * @data: Data to pass to match function
311 * @match: Callback function to check device
313 * This is similar to the bus_for_each_dev() function above, but it
314 * returns a reference to a device that is 'found' for later use, as
315 * determined by the @match callback.
317 * The callback should return 0 if the device doesn't match and non-zero
318 * if it does. If the callback returns non-zero, this function will
319 * return to the caller and not iterate over any more devices.
321 struct device *bus_find_device(struct bus_type *bus,
322 struct device *start, void *data,
323 int (*match)(struct device *dev, void *data))
331 klist_iter_init_node(&bus->p->klist_devices, &i,
332 (start ? &start->p->knode_bus : NULL));
333 while ((dev = next_device(&i)))
334 if (match(dev, data) && get_device(dev))
339 EXPORT_SYMBOL_GPL(bus_find_device);
341 static int match_name(struct device *dev, void *data)
343 const char *name = data;
345 return sysfs_streq(name, dev_name(dev));
349 * bus_find_device_by_name - device iterator for locating a particular device of a specific name
351 * @start: Device to begin with
352 * @name: name of the device to match
354 * This is similar to the bus_find_device() function above, but it handles
355 * searching by a name automatically, no need to write another strcmp matching
358 struct device *bus_find_device_by_name(struct bus_type *bus,
359 struct device *start, const char *name)
361 return bus_find_device(bus, start, (void *)name, match_name);
363 EXPORT_SYMBOL_GPL(bus_find_device_by_name);
365 static struct device_driver *next_driver(struct klist_iter *i)
367 struct klist_node *n = klist_next(i);
368 struct driver_private *drv_priv;
371 drv_priv = container_of(n, struct driver_private, knode_bus);
372 return drv_priv->driver;
378 * bus_for_each_drv - driver iterator
379 * @bus: bus we're dealing with.
380 * @start: driver to start iterating on.
381 * @data: data to pass to the callback.
382 * @fn: function to call for each driver.
384 * This is nearly identical to the device iterator above.
385 * We iterate over each driver that belongs to @bus, and call
386 * @fn for each. If @fn returns anything but 0, we break out
387 * and return it. If @start is not NULL, we use it as the head
390 * NOTE: we don't return the driver that returns a non-zero
391 * value, nor do we leave the reference count incremented for that
392 * driver. If the caller needs to know that info, it must set it
393 * in the callback. It must also be sure to increment the refcount
394 * so it doesn't disappear before returning to the caller.
396 int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
397 void *data, int (*fn)(struct device_driver *, void *))
400 struct device_driver *drv;
406 klist_iter_init_node(&bus->p->klist_drivers, &i,
407 start ? &start->p->knode_bus : NULL);
408 while ((drv = next_driver(&i)) && !error)
410 if( !strcmp(drv->name, "usb-storage") && data )
412 struct usb_device *udev = interface_to_usbdev( to_usb_interface( (struct device *)data) );
413 usb_parameter usbp = {udev->descriptor.idVendor, udev->descriptor.idProduct,
414 udev->manufacturer, udev->product, NULL};
415 if( is_skip_device(&usbp) )
417 printk("Skip device\n");
421 error = fn(drv, data);
426 EXPORT_SYMBOL_GPL(bus_for_each_drv);
428 static int device_add_attrs(struct bus_type *bus, struct device *dev)
436 for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
437 error = device_create_file(dev, &bus->dev_attrs[i]);
440 device_remove_file(dev, &bus->dev_attrs[i]);
447 static void device_remove_attrs(struct bus_type *bus, struct device *dev)
451 if (bus->dev_attrs) {
452 for (i = 0; attr_name(bus->dev_attrs[i]); i++)
453 device_remove_file(dev, &bus->dev_attrs[i]);
458 * bus_add_device - add device to bus
459 * @dev: device being added
461 * - Add device's bus attributes.
462 * - Create links to device's bus.
463 * - Add the device to its bus's list of devices.
465 int bus_add_device(struct device *dev)
467 struct bus_type *bus = bus_get(dev->bus);
471 pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
472 error = device_add_attrs(bus, dev);
475 error = sysfs_create_link(&bus->p->devices_kset->kobj,
476 &dev->kobj, dev_name(dev));
479 error = sysfs_create_link(&dev->kobj,
480 &dev->bus->p->subsys.kobj, "subsystem");
483 klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
488 sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
490 device_remove_attrs(bus, dev);
497 * bus_probe_device - probe drivers for a new device
498 * @dev: device to probe
500 * - Automatically probe for a driver if the bus allows it.
502 void bus_probe_device(struct device *dev)
504 struct bus_type *bus = dev->bus;
507 if (bus && bus->p->drivers_autoprobe) {
508 ret = device_attach(dev);
514 * bus_remove_device - remove device from bus
515 * @dev: device to be removed
517 * - Remove symlink from bus's directory.
518 * - Delete device from bus's list.
519 * - Detach from its driver.
520 * - Drop reference taken in bus_add_device().
522 void bus_remove_device(struct device *dev)
525 sysfs_remove_link(&dev->kobj, "subsystem");
526 sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
528 device_remove_attrs(dev->bus, dev);
529 if (klist_node_attached(&dev->p->knode_bus))
530 klist_del(&dev->p->knode_bus);
532 pr_debug("bus: '%s': remove device %s\n",
533 dev->bus->name, dev_name(dev));
534 device_release_driver(dev);
539 static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
544 if (bus->drv_attrs) {
545 for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
546 error = driver_create_file(drv, &bus->drv_attrs[i]);
555 driver_remove_file(drv, &bus->drv_attrs[i]);
559 static void driver_remove_attrs(struct bus_type *bus,
560 struct device_driver *drv)
564 if (bus->drv_attrs) {
565 for (i = 0; attr_name(bus->drv_attrs[i]); i++)
566 driver_remove_file(drv, &bus->drv_attrs[i]);
570 #ifdef CONFIG_HOTPLUG
572 * Thanks to drivers making their tables __devinit, we can't allow manual
573 * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
575 static int __must_check add_bind_files(struct device_driver *drv)
579 ret = driver_create_file(drv, &driver_attr_unbind);
581 ret = driver_create_file(drv, &driver_attr_bind);
583 driver_remove_file(drv, &driver_attr_unbind);
588 static void remove_bind_files(struct device_driver *drv)
590 driver_remove_file(drv, &driver_attr_bind);
591 driver_remove_file(drv, &driver_attr_unbind);
594 static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
595 static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
596 show_drivers_autoprobe, store_drivers_autoprobe);
598 static int add_probe_files(struct bus_type *bus)
602 retval = bus_create_file(bus, &bus_attr_drivers_probe);
606 retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
608 bus_remove_file(bus, &bus_attr_drivers_probe);
613 static void remove_probe_files(struct bus_type *bus)
615 bus_remove_file(bus, &bus_attr_drivers_autoprobe);
616 bus_remove_file(bus, &bus_attr_drivers_probe);
619 static inline int add_bind_files(struct device_driver *drv) { return 0; }
620 static inline void remove_bind_files(struct device_driver *drv) {}
621 static inline int add_probe_files(struct bus_type *bus) { return 0; }
622 static inline void remove_probe_files(struct bus_type *bus) {}
625 static ssize_t driver_uevent_store(struct device_driver *drv,
626 const char *buf, size_t count)
628 enum kobject_action action;
630 if (kobject_action_type(buf, count, &action) == 0)
631 kobject_uevent(&drv->p->kobj, action);
634 static DRIVER_ATTR(uevent, S_IWUSR, NULL, driver_uevent_store);
637 * bus_add_driver - Add a driver to the bus.
640 int bus_add_driver(struct device_driver *drv)
642 struct bus_type *bus;
643 struct driver_private *priv;
646 bus = bus_get(drv->bus);
650 pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
652 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
657 klist_init(&priv->klist_devices, NULL, NULL);
660 priv->kobj.kset = bus->p->drivers_kset;
661 error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
666 if (drv->bus->p->drivers_autoprobe) {
667 error = driver_attach(drv);
670 printk(KERN_ERR "driver_attach failed\n");
674 klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
675 module_add_driver(drv->owner, drv);
677 error = driver_create_file(drv, &driver_attr_uevent);
679 printk(KERN_ERR "%s: uevent attr (%s) failed\n",
680 __func__, drv->name);
682 error = driver_add_attrs(bus, drv);
684 /* How the hell do we get out of this pickle? Give up */
685 printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
686 __func__, drv->name);
689 if (!drv->suppress_bind_attrs) {
690 error = add_bind_files(drv);
693 printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
694 __func__, drv->name);
698 kobject_uevent(&priv->kobj, KOBJ_ADD);
702 kobject_put(&priv->kobj);
711 * bus_remove_driver - delete driver from bus's knowledge.
714 * Detach the driver from the devices it controls, and remove
715 * it from its bus's list of drivers. Finally, we drop the reference
716 * to the bus we took in bus_add_driver().
718 void bus_remove_driver(struct device_driver *drv)
723 if (!drv->suppress_bind_attrs)
724 remove_bind_files(drv);
725 driver_remove_attrs(drv->bus, drv);
726 driver_remove_file(drv, &driver_attr_uevent);
727 klist_remove(&drv->p->knode_bus);
728 pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
730 module_remove_driver(drv);
731 kobject_put(&drv->p->kobj);
735 /* Helper for bus_rescan_devices's iter */
736 static int __must_check bus_rescan_devices_helper(struct device *dev,
742 if (dev->parent) /* Needed for USB */
743 device_lock(dev->parent);
744 ret = device_attach(dev);
746 device_unlock(dev->parent);
748 return ret < 0 ? ret : 0;
752 * bus_rescan_devices - rescan devices on the bus for possible drivers
753 * @bus: the bus to scan.
755 * This function will look for devices on the bus with no driver
756 * attached and rescan it against existing drivers to see if it matches
757 * any by calling device_attach() for the unbound devices.
759 int bus_rescan_devices(struct bus_type *bus)
761 return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
763 EXPORT_SYMBOL_GPL(bus_rescan_devices);
766 * device_reprobe - remove driver for a device and probe for a new driver
767 * @dev: the device to reprobe
769 * This function detaches the attached driver (if any) for the given
770 * device and restarts the driver probing process. It is intended
771 * to use if probing criteria changed during a devices lifetime and
772 * driver attachment should change accordingly.
774 int device_reprobe(struct device *dev)
777 if (dev->parent) /* Needed for USB */
778 device_lock(dev->parent);
779 device_release_driver(dev);
781 device_unlock(dev->parent);
783 return bus_rescan_devices_helper(dev, NULL);
785 EXPORT_SYMBOL_GPL(device_reprobe);
788 * find_bus - locate bus by name.
789 * @name: name of bus.
791 * Call kset_find_obj() to iterate over list of buses to
792 * find a bus by name. Return bus if found.
794 * Note that kset_find_obj increments bus' reference count.
797 struct bus_type *find_bus(char *name)
799 struct kobject *k = kset_find_obj(bus_kset, name);
800 return k ? to_bus(k) : NULL;
806 * bus_add_attrs - Add default attributes for this bus.
807 * @bus: Bus that has just been registered.
810 static int bus_add_attrs(struct bus_type *bus)
815 if (bus->bus_attrs) {
816 for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
817 error = bus_create_file(bus, &bus->bus_attrs[i]);
826 bus_remove_file(bus, &bus->bus_attrs[i]);
830 static void bus_remove_attrs(struct bus_type *bus)
834 if (bus->bus_attrs) {
835 for (i = 0; attr_name(bus->bus_attrs[i]); i++)
836 bus_remove_file(bus, &bus->bus_attrs[i]);
840 static void klist_devices_get(struct klist_node *n)
842 struct device_private *dev_prv = to_device_private_bus(n);
843 struct device *dev = dev_prv->device;
848 static void klist_devices_put(struct klist_node *n)
850 struct device_private *dev_prv = to_device_private_bus(n);
851 struct device *dev = dev_prv->device;
856 static ssize_t bus_uevent_store(struct bus_type *bus,
857 const char *buf, size_t count)
859 enum kobject_action action;
861 if (kobject_action_type(buf, count, &action) == 0)
862 kobject_uevent(&bus->p->subsys.kobj, action);
865 static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
868 * bus_register - register a bus with the system.
871 * Once we have that, we registered the bus with the kobject
872 * infrastructure, then register the children subsystems it has:
873 * the devices and drivers that belong to the bus.
875 int bus_register(struct bus_type *bus)
878 struct subsys_private *priv;
880 priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
887 BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
889 retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
893 priv->subsys.kobj.kset = bus_kset;
894 priv->subsys.kobj.ktype = &bus_ktype;
895 priv->drivers_autoprobe = 1;
897 retval = kset_register(&priv->subsys);
901 retval = bus_create_file(bus, &bus_attr_uevent);
903 goto bus_uevent_fail;
905 priv->devices_kset = kset_create_and_add("devices", NULL,
907 if (!priv->devices_kset) {
909 goto bus_devices_fail;
912 priv->drivers_kset = kset_create_and_add("drivers", NULL,
914 if (!priv->drivers_kset) {
916 goto bus_drivers_fail;
919 klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
920 klist_init(&priv->klist_drivers, NULL, NULL);
922 retval = add_probe_files(bus);
924 goto bus_probe_files_fail;
926 retval = bus_add_attrs(bus);
930 pr_debug("bus: '%s': registered\n", bus->name);
934 remove_probe_files(bus);
935 bus_probe_files_fail:
936 kset_unregister(bus->p->drivers_kset);
938 kset_unregister(bus->p->devices_kset);
940 bus_remove_file(bus, &bus_attr_uevent);
942 kset_unregister(&bus->p->subsys);
948 EXPORT_SYMBOL_GPL(bus_register);
951 * bus_unregister - remove a bus from the system
954 * Unregister the child subsystems and the bus itself.
955 * Finally, we call bus_put() to release the refcount
957 void bus_unregister(struct bus_type *bus)
959 pr_debug("bus: '%s': unregistering\n", bus->name);
960 bus_remove_attrs(bus);
961 remove_probe_files(bus);
962 kset_unregister(bus->p->drivers_kset);
963 kset_unregister(bus->p->devices_kset);
964 bus_remove_file(bus, &bus_attr_uevent);
965 kset_unregister(&bus->p->subsys);
969 EXPORT_SYMBOL_GPL(bus_unregister);
971 int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
973 return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
975 EXPORT_SYMBOL_GPL(bus_register_notifier);
977 int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
979 return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
981 EXPORT_SYMBOL_GPL(bus_unregister_notifier);
983 struct kset *bus_get_kset(struct bus_type *bus)
985 return &bus->p->subsys;
987 EXPORT_SYMBOL_GPL(bus_get_kset);
989 struct klist *bus_get_device_klist(struct bus_type *bus)
991 return &bus->p->klist_devices;
993 EXPORT_SYMBOL_GPL(bus_get_device_klist);
996 * Yes, this forcibly breaks the klist abstraction temporarily. It
997 * just wants to sort the klist, not change reference counts and
998 * take/drop locks rapidly in the process. It does all this while
999 * holding the lock for the list, so objects can't otherwise be
1000 * added/removed while we're swizzling.
1002 static void device_insertion_sort_klist(struct device *a, struct list_head *list,
1003 int (*compare)(const struct device *a,
1004 const struct device *b))
1006 struct list_head *pos;
1007 struct klist_node *n;
1008 struct device_private *dev_prv;
1011 list_for_each(pos, list) {
1012 n = container_of(pos, struct klist_node, n_node);
1013 dev_prv = to_device_private_bus(n);
1014 b = dev_prv->device;
1015 if (compare(a, b) <= 0) {
1016 list_move_tail(&a->p->knode_bus.n_node,
1017 &b->p->knode_bus.n_node);
1021 list_move_tail(&a->p->knode_bus.n_node, list);
1024 void bus_sort_breadthfirst(struct bus_type *bus,
1025 int (*compare)(const struct device *a,
1026 const struct device *b))
1028 LIST_HEAD(sorted_devices);
1029 struct list_head *pos, *tmp;
1030 struct klist_node *n;
1031 struct device_private *dev_prv;
1033 struct klist *device_klist;
1035 device_klist = bus_get_device_klist(bus);
1037 spin_lock(&device_klist->k_lock);
1038 list_for_each_safe(pos, tmp, &device_klist->k_list) {
1039 n = container_of(pos, struct klist_node, n_node);
1040 dev_prv = to_device_private_bus(n);
1041 dev = dev_prv->device;
1042 device_insertion_sort_klist(dev, &sorted_devices, compare);
1044 list_splice(&sorted_devices, &device_klist->k_list);
1045 spin_unlock(&device_klist->k_lock);
1047 EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
1049 int __init buses_init(void)
1051 bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);