1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/base/dd.c - The core device/driver interactions.
5 * This file contains the (sometimes tricky) code that controls the
6 * interactions between devices and drivers, which primarily includes
7 * driver binding and unbinding.
9 * All of this code used to exist in drivers/base/bus.c, but was
10 * relocated to here in the name of compartmentalization (since it wasn't
11 * strictly code just for the 'struct bus_type'.
13 * Copyright (c) 2002-5 Patrick Mochel
14 * Copyright (c) 2002-3 Open Source Development Labs
15 * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
16 * Copyright (c) 2007-2009 Novell Inc.
19 #include <linux/device.h>
20 #include <linux/delay.h>
21 #include <linux/dma-mapping.h>
22 #include <linux/init.h>
23 #include <linux/module.h>
24 #include <linux/kthread.h>
25 #include <linux/wait.h>
26 #include <linux/async.h>
27 #include <linux/pm_runtime.h>
28 #include <linux/pinctrl/devinfo.h>
31 #include "power/power.h"
34 * Deferred Probe infrastructure.
36 * Sometimes driver probe order matters, but the kernel doesn't always have
37 * dependency information which means some drivers will get probed before a
38 * resource it depends on is available. For example, an SDHCI driver may
39 * first need a GPIO line from an i2c GPIO controller before it can be
40 * initialized. If a required resource is not available yet, a driver can
41 * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
43 * Deferred probe maintains two lists of devices, a pending list and an active
44 * list. A driver returning -EPROBE_DEFER causes the device to be added to the
45 * pending list. A successful driver probe will trigger moving all devices
46 * from the pending to the active list so that the workqueue will eventually
49 * The deferred_probe_mutex must be held any time the deferred_probe_*_list
50 * of the (struct device*)->p->deferred_probe pointers are manipulated
52 static DEFINE_MUTEX(deferred_probe_mutex
);
53 static LIST_HEAD(deferred_probe_pending_list
);
54 static LIST_HEAD(deferred_probe_active_list
);
55 static atomic_t deferred_trigger_count
= ATOMIC_INIT(0);
56 static bool initcalls_done
;
59 * In some cases, like suspend to RAM or hibernation, It might be reasonable
60 * to prohibit probing of devices as it could be unsafe.
61 * Once defer_all_probes is true all drivers probes will be forcibly deferred.
63 static bool defer_all_probes
;
66 * For initcall_debug, show the deferred probes executed in late_initcall
69 static void deferred_probe_debug(struct device
*dev
)
71 ktime_t calltime
, delta
, rettime
;
72 unsigned long long duration
;
74 printk(KERN_DEBUG
"deferred probe %s @ %i\n", dev_name(dev
),
75 task_pid_nr(current
));
76 calltime
= ktime_get();
77 bus_probe_device(dev
);
78 rettime
= ktime_get();
79 delta
= ktime_sub(rettime
, calltime
);
80 duration
= (unsigned long long) ktime_to_ns(delta
) >> 10;
81 printk(KERN_DEBUG
"deferred probe %s returned after %lld usecs\n",
82 dev_name(dev
), duration
);
86 * deferred_probe_work_func() - Retry probing devices in the active list.
88 static void deferred_probe_work_func(struct work_struct
*work
)
91 struct device_private
*private;
93 * This block processes every device in the deferred 'active' list.
94 * Each device is removed from the active list and passed to
95 * bus_probe_device() to re-attempt the probe. The loop continues
96 * until every device in the active list is removed and retried.
98 * Note: Once the device is removed from the list and the mutex is
99 * released, it is possible for the device get freed by another thread
100 * and cause a illegal pointer dereference. This code uses
101 * get/put_device() to ensure the device structure cannot disappear
102 * from under our feet.
104 mutex_lock(&deferred_probe_mutex
);
105 while (!list_empty(&deferred_probe_active_list
)) {
106 private = list_first_entry(&deferred_probe_active_list
,
107 typeof(*dev
->p
), deferred_probe
);
108 dev
= private->device
;
109 list_del_init(&private->deferred_probe
);
114 * Drop the mutex while probing each device; the probe path may
115 * manipulate the deferred list
117 mutex_unlock(&deferred_probe_mutex
);
120 * Force the device to the end of the dpm_list since
121 * the PM code assumes that the order we add things to
122 * the list is a good order for suspend but deferred
123 * probe makes that very unsafe.
125 device_pm_move_to_tail(dev
);
127 dev_dbg(dev
, "Retrying from deferred list\n");
128 if (initcall_debug
&& !initcalls_done
)
129 deferred_probe_debug(dev
);
131 bus_probe_device(dev
);
133 mutex_lock(&deferred_probe_mutex
);
137 mutex_unlock(&deferred_probe_mutex
);
139 static DECLARE_WORK(deferred_probe_work
, deferred_probe_work_func
);
141 static void driver_deferred_probe_add(struct device
*dev
)
143 mutex_lock(&deferred_probe_mutex
);
144 if (list_empty(&dev
->p
->deferred_probe
)) {
145 dev_dbg(dev
, "Added to deferred list\n");
146 list_add_tail(&dev
->p
->deferred_probe
, &deferred_probe_pending_list
);
148 mutex_unlock(&deferred_probe_mutex
);
151 void driver_deferred_probe_del(struct device
*dev
)
153 mutex_lock(&deferred_probe_mutex
);
154 if (!list_empty(&dev
->p
->deferred_probe
)) {
155 dev_dbg(dev
, "Removed from deferred list\n");
156 list_del_init(&dev
->p
->deferred_probe
);
158 mutex_unlock(&deferred_probe_mutex
);
161 static bool driver_deferred_probe_enable
= false;
163 * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
165 * This functions moves all devices from the pending list to the active
166 * list and schedules the deferred probe workqueue to process them. It
167 * should be called anytime a driver is successfully bound to a device.
169 * Note, there is a race condition in multi-threaded probe. In the case where
170 * more than one device is probing at the same time, it is possible for one
171 * probe to complete successfully while another is about to defer. If the second
172 * depends on the first, then it will get put on the pending list after the
173 * trigger event has already occurred and will be stuck there.
175 * The atomic 'deferred_trigger_count' is used to determine if a successful
176 * trigger has occurred in the midst of probing a driver. If the trigger count
177 * changes in the midst of a probe, then deferred processing should be triggered
180 static void driver_deferred_probe_trigger(void)
182 if (!driver_deferred_probe_enable
)
186 * A successful probe means that all the devices in the pending list
187 * should be triggered to be reprobed. Move all the deferred devices
188 * into the active list so they can be retried by the workqueue
190 mutex_lock(&deferred_probe_mutex
);
191 atomic_inc(&deferred_trigger_count
);
192 list_splice_tail_init(&deferred_probe_pending_list
,
193 &deferred_probe_active_list
);
194 mutex_unlock(&deferred_probe_mutex
);
197 * Kick the re-probe thread. It may already be scheduled, but it is
198 * safe to kick it again.
200 schedule_work(&deferred_probe_work
);
204 * device_block_probing() - Block/defere device's probes
206 * It will disable probing of devices and defer their probes instead.
208 void device_block_probing(void)
210 defer_all_probes
= true;
211 /* sync with probes to avoid races. */
212 wait_for_device_probe();
216 * device_unblock_probing() - Unblock/enable device's probes
218 * It will restore normal behavior and trigger re-probing of deferred
221 void device_unblock_probing(void)
223 defer_all_probes
= false;
224 driver_deferred_probe_trigger();
228 * deferred_probe_initcall() - Enable probing of deferred devices
230 * We don't want to get in the way when the bulk of drivers are getting probed.
231 * Instead, this initcall makes sure that deferred probing is delayed until
232 * late_initcall time.
234 static int deferred_probe_initcall(void)
236 driver_deferred_probe_enable
= true;
237 driver_deferred_probe_trigger();
238 /* Sort as many dependencies as possible before exiting initcalls */
239 flush_work(&deferred_probe_work
);
240 initcalls_done
= true;
243 late_initcall(deferred_probe_initcall
);
246 * device_is_bound() - Check if device is bound to a driver
247 * @dev: device to check
249 * Returns true if passed device has already finished probing successfully
252 * This function must be called with the device lock held.
254 bool device_is_bound(struct device
*dev
)
256 return dev
->p
&& klist_node_attached(&dev
->p
->knode_driver
);
259 static void driver_bound(struct device
*dev
)
261 if (device_is_bound(dev
)) {
262 printk(KERN_WARNING
"%s: device %s already bound\n",
263 __func__
, kobject_name(&dev
->kobj
));
267 pr_debug("driver: '%s': %s: bound to device '%s'\n", dev
->driver
->name
,
268 __func__
, dev_name(dev
));
270 klist_add_tail(&dev
->p
->knode_driver
, &dev
->driver
->p
->klist_devices
);
271 device_links_driver_bound(dev
);
273 device_pm_check_callbacks(dev
);
276 * Make sure the device is no longer in one of the deferred lists and
277 * kick off retrying all pending devices
279 driver_deferred_probe_del(dev
);
280 driver_deferred_probe_trigger();
283 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
284 BUS_NOTIFY_BOUND_DRIVER
, dev
);
286 kobject_uevent(&dev
->kobj
, KOBJ_BIND
);
289 static ssize_t
coredump_store(struct device
*dev
, struct device_attribute
*attr
,
290 const char *buf
, size_t count
)
293 dev
->driver
->coredump(dev
);
298 static DEVICE_ATTR_WO(coredump
);
300 static int driver_sysfs_add(struct device
*dev
)
305 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
306 BUS_NOTIFY_BIND_DRIVER
, dev
);
308 ret
= sysfs_create_link(&dev
->driver
->p
->kobj
, &dev
->kobj
,
309 kobject_name(&dev
->kobj
));
313 ret
= sysfs_create_link(&dev
->kobj
, &dev
->driver
->p
->kobj
,
318 if (!IS_ENABLED(CONFIG_DEV_COREDUMP
) || !dev
->driver
->coredump
||
319 !device_create_file(dev
, &dev_attr_coredump
))
322 sysfs_remove_link(&dev
->kobj
, "driver");
325 sysfs_remove_link(&dev
->driver
->p
->kobj
,
326 kobject_name(&dev
->kobj
));
332 static void driver_sysfs_remove(struct device
*dev
)
334 struct device_driver
*drv
= dev
->driver
;
338 device_remove_file(dev
, &dev_attr_coredump
);
339 sysfs_remove_link(&drv
->p
->kobj
, kobject_name(&dev
->kobj
));
340 sysfs_remove_link(&dev
->kobj
, "driver");
345 * device_bind_driver - bind a driver to one device.
348 * Allow manual attachment of a driver to a device.
349 * Caller must have already set @dev->driver.
351 * Note that this does not modify the bus reference count
352 * nor take the bus's rwsem. Please verify those are accounted
353 * for before calling this. (It is ok to call with no other effort
354 * from a driver's probe() method.)
356 * This function must be called with the device lock held.
358 int device_bind_driver(struct device
*dev
)
362 ret
= driver_sysfs_add(dev
);
366 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
367 BUS_NOTIFY_DRIVER_NOT_BOUND
, dev
);
370 EXPORT_SYMBOL_GPL(device_bind_driver
);
372 static atomic_t probe_count
= ATOMIC_INIT(0);
373 static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue
);
375 static void driver_deferred_probe_add_trigger(struct device
*dev
,
376 int local_trigger_count
)
378 driver_deferred_probe_add(dev
);
379 /* Did a trigger occur while probing? Need to re-trigger if yes */
380 if (local_trigger_count
!= atomic_read(&deferred_trigger_count
))
381 driver_deferred_probe_trigger();
384 static int really_probe(struct device
*dev
, struct device_driver
*drv
)
386 int ret
= -EPROBE_DEFER
;
387 int local_trigger_count
= atomic_read(&deferred_trigger_count
);
388 bool test_remove
= IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE
) &&
389 !drv
->suppress_bind_attrs
;
391 if (defer_all_probes
) {
393 * Value of defer_all_probes can be set only by
394 * device_defer_all_probes_enable() which, in turn, will call
395 * wait_for_device_probe() right after that to avoid any races.
397 dev_dbg(dev
, "Driver %s force probe deferral\n", drv
->name
);
398 driver_deferred_probe_add(dev
);
402 ret
= device_links_check_suppliers(dev
);
403 if (ret
== -EPROBE_DEFER
)
404 driver_deferred_probe_add_trigger(dev
, local_trigger_count
);
408 atomic_inc(&probe_count
);
409 pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
410 drv
->bus
->name
, __func__
, drv
->name
, dev_name(dev
));
411 WARN_ON(!list_empty(&dev
->devres_head
));
416 /* If using pinctrl, bind pins now before probing */
417 ret
= pinctrl_bind_pins(dev
);
419 goto pinctrl_bind_failed
;
421 ret
= dma_configure(dev
);
425 if (driver_sysfs_add(dev
)) {
426 printk(KERN_ERR
"%s: driver_sysfs_add(%s) failed\n",
427 __func__
, dev_name(dev
));
431 if (dev
->pm_domain
&& dev
->pm_domain
->activate
) {
432 ret
= dev
->pm_domain
->activate(dev
);
438 * Ensure devices are listed in devices_kset in correct order
439 * It's important to move Dev to the end of devices_kset before
440 * calling .probe, because it could be recursive and parent Dev
441 * should always go first
443 devices_kset_move_last(dev
);
445 if (dev
->bus
->probe
) {
446 ret
= dev
->bus
->probe(dev
);
449 } else if (drv
->probe
) {
450 ret
= drv
->probe(dev
);
458 if (dev
->bus
->remove
)
459 dev
->bus
->remove(dev
);
460 else if (drv
->remove
)
463 devres_release_all(dev
);
464 driver_sysfs_remove(dev
);
466 dev_set_drvdata(dev
, NULL
);
467 if (dev
->pm_domain
&& dev
->pm_domain
->dismiss
)
468 dev
->pm_domain
->dismiss(dev
);
469 pm_runtime_reinit(dev
);
474 pinctrl_init_done(dev
);
476 if (dev
->pm_domain
&& dev
->pm_domain
->sync
)
477 dev
->pm_domain
->sync(dev
);
481 pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
482 drv
->bus
->name
, __func__
, dev_name(dev
), drv
->name
);
486 dma_deconfigure(dev
);
489 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
490 BUS_NOTIFY_DRIVER_NOT_BOUND
, dev
);
492 device_links_no_driver(dev
);
493 devres_release_all(dev
);
494 driver_sysfs_remove(dev
);
496 dev_set_drvdata(dev
, NULL
);
497 if (dev
->pm_domain
&& dev
->pm_domain
->dismiss
)
498 dev
->pm_domain
->dismiss(dev
);
499 pm_runtime_reinit(dev
);
500 dev_pm_set_driver_flags(dev
, 0);
504 /* Driver requested deferred probing */
505 dev_dbg(dev
, "Driver %s requests probe deferral\n", drv
->name
);
506 driver_deferred_probe_add_trigger(dev
, local_trigger_count
);
510 pr_debug("%s: probe of %s rejects match %d\n",
511 drv
->name
, dev_name(dev
), ret
);
514 /* driver matched but the probe failed */
516 "%s: probe of %s failed with error %d\n",
517 drv
->name
, dev_name(dev
), ret
);
520 * Ignore errors returned by ->probe so that the next driver can try
525 atomic_dec(&probe_count
);
526 wake_up(&probe_waitqueue
);
532 * Determine if the probe sequence is finished or not.
534 * Should somehow figure out how to use a semaphore, not an atomic variable...
536 int driver_probe_done(void)
538 pr_debug("%s: probe_count = %d\n", __func__
,
539 atomic_read(&probe_count
));
540 if (atomic_read(&probe_count
))
546 * wait_for_device_probe
547 * Wait for device probing to be completed.
549 void wait_for_device_probe(void)
551 /* wait for the deferred probe workqueue to finish */
552 flush_work(&deferred_probe_work
);
554 /* wait for the known devices to complete their probing */
555 wait_event(probe_waitqueue
, atomic_read(&probe_count
) == 0);
556 async_synchronize_full();
558 EXPORT_SYMBOL_GPL(wait_for_device_probe
);
561 * driver_probe_device - attempt to bind device & driver together
562 * @drv: driver to bind a device to
563 * @dev: device to try to bind to the driver
565 * This function returns -ENODEV if the device is not registered,
566 * 1 if the device is bound successfully and 0 otherwise.
568 * This function must be called with @dev lock held. When called for a
569 * USB interface, @dev->parent lock must be held as well.
571 * If the device has a parent, runtime-resume the parent before driver probing.
573 int driver_probe_device(struct device_driver
*drv
, struct device
*dev
)
577 if (!device_is_registered(dev
))
580 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
581 drv
->bus
->name
, __func__
, dev_name(dev
), drv
->name
);
583 pm_runtime_get_suppliers(dev
);
585 pm_runtime_get_sync(dev
->parent
);
587 pm_runtime_barrier(dev
);
588 ret
= really_probe(dev
, drv
);
589 pm_request_idle(dev
);
592 pm_runtime_put(dev
->parent
);
594 pm_runtime_put_suppliers(dev
);
598 bool driver_allows_async_probing(struct device_driver
*drv
)
600 switch (drv
->probe_type
) {
601 case PROBE_PREFER_ASYNCHRONOUS
:
604 case PROBE_FORCE_SYNCHRONOUS
:
608 if (module_requested_async_probing(drv
->owner
))
615 struct device_attach_data
{
619 * Indicates whether we are are considering asynchronous probing or
620 * not. Only initial binding after device or driver registration
621 * (including deferral processing) may be done asynchronously, the
622 * rest is always synchronous, as we expect it is being done by
623 * request from userspace.
628 * Indicates if we are binding synchronous or asynchronous drivers.
629 * When asynchronous probing is enabled we'll execute 2 passes
630 * over drivers: first pass doing synchronous probing and second
631 * doing asynchronous probing (if synchronous did not succeed -
632 * most likely because there was no driver requiring synchronous
633 * probing - and we found asynchronous driver during first pass).
634 * The 2 passes are done because we can't shoot asynchronous
635 * probe for given device and driver from bus_for_each_drv() since
636 * driver pointer is not guaranteed to stay valid once
637 * bus_for_each_drv() iterates to the next driver on the bus.
642 * We'll set have_async to 'true' if, while scanning for matching
643 * driver, we'll encounter one that requests asynchronous probing.
648 static int __device_attach_driver(struct device_driver
*drv
, void *_data
)
650 struct device_attach_data
*data
= _data
;
651 struct device
*dev
= data
->dev
;
656 * Check if device has already been claimed. This may
657 * happen with driver loading, device discovery/registration,
658 * and deferred probe processing happens all at once with
664 ret
= driver_match_device(drv
, dev
);
668 } else if (ret
== -EPROBE_DEFER
) {
669 dev_dbg(dev
, "Device match requests probe deferral\n");
670 driver_deferred_probe_add(dev
);
671 } else if (ret
< 0) {
672 dev_dbg(dev
, "Bus failed to match device: %d", ret
);
674 } /* ret > 0 means positive match */
676 async_allowed
= driver_allows_async_probing(drv
);
679 data
->have_async
= true;
681 if (data
->check_async
&& async_allowed
!= data
->want_async
)
684 return driver_probe_device(drv
, dev
);
687 static void __device_attach_async_helper(void *_dev
, async_cookie_t cookie
)
689 struct device
*dev
= _dev
;
690 struct device_attach_data data
= {
699 pm_runtime_get_sync(dev
->parent
);
701 bus_for_each_drv(dev
->bus
, NULL
, &data
, __device_attach_driver
);
702 dev_dbg(dev
, "async probe completed\n");
704 pm_request_idle(dev
);
707 pm_runtime_put(dev
->parent
);
714 static int __device_attach(struct device
*dev
, bool allow_async
)
720 if (device_is_bound(dev
)) {
724 ret
= device_bind_driver(dev
);
732 struct device_attach_data data
= {
734 .check_async
= allow_async
,
739 pm_runtime_get_sync(dev
->parent
);
741 ret
= bus_for_each_drv(dev
->bus
, NULL
, &data
,
742 __device_attach_driver
);
743 if (!ret
&& allow_async
&& data
.have_async
) {
745 * If we could not find appropriate driver
746 * synchronously and we are allowed to do
747 * async probes and there are drivers that
748 * want to probe asynchronously, we'll
751 dev_dbg(dev
, "scheduling asynchronous probe\n");
753 async_schedule(__device_attach_async_helper
, dev
);
755 pm_request_idle(dev
);
759 pm_runtime_put(dev
->parent
);
767 * device_attach - try to attach device to a driver.
770 * Walk the list of drivers that the bus has and call
771 * driver_probe_device() for each pair. If a compatible
772 * pair is found, break out and return.
774 * Returns 1 if the device was bound to a driver;
775 * 0 if no matching driver was found;
776 * -ENODEV if the device is not registered.
778 * When called for a USB interface, @dev->parent lock must be held.
780 int device_attach(struct device
*dev
)
782 return __device_attach(dev
, false);
784 EXPORT_SYMBOL_GPL(device_attach
);
786 void device_initial_probe(struct device
*dev
)
788 __device_attach(dev
, true);
791 static int __driver_attach(struct device
*dev
, void *data
)
793 struct device_driver
*drv
= data
;
797 * Lock device and try to bind to it. We drop the error
798 * here and always return 0, because we need to keep trying
799 * to bind to devices and some drivers will return an error
800 * simply if it didn't support the device.
802 * driver_probe_device() will spit a warning if there
806 ret
= driver_match_device(drv
, dev
);
810 } else if (ret
== -EPROBE_DEFER
) {
811 dev_dbg(dev
, "Device match requests probe deferral\n");
812 driver_deferred_probe_add(dev
);
813 } else if (ret
< 0) {
814 dev_dbg(dev
, "Bus failed to match device: %d", ret
);
816 } /* ret > 0 means positive match */
818 if (dev
->parent
&& dev
->bus
->need_parent_lock
)
819 device_lock(dev
->parent
);
822 driver_probe_device(drv
, dev
);
824 if (dev
->parent
&& dev
->bus
->need_parent_lock
)
825 device_unlock(dev
->parent
);
831 * driver_attach - try to bind driver to devices.
834 * Walk the list of devices that the bus has on it and try to
835 * match the driver with each one. If driver_probe_device()
836 * returns 0 and the @dev->driver is set, we've found a
839 int driver_attach(struct device_driver
*drv
)
841 return bus_for_each_dev(drv
->bus
, NULL
, drv
, __driver_attach
);
843 EXPORT_SYMBOL_GPL(driver_attach
);
846 * __device_release_driver() must be called with @dev lock held.
847 * When called for a USB interface, @dev->parent lock must be held as well.
849 static void __device_release_driver(struct device
*dev
, struct device
*parent
)
851 struct device_driver
*drv
;
855 if (driver_allows_async_probing(drv
))
856 async_synchronize_full();
858 while (device_links_busy(dev
)) {
861 device_unlock(parent
);
863 device_links_unbind_consumers(dev
);
869 * A concurrent invocation of the same function might
870 * have released the driver successfully while this one
871 * was waiting, so check for that.
873 if (dev
->driver
!= drv
)
877 pm_runtime_get_sync(dev
);
878 pm_runtime_clean_up_links(dev
);
880 driver_sysfs_remove(dev
);
883 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
884 BUS_NOTIFY_UNBIND_DRIVER
,
887 pm_runtime_put_sync(dev
);
889 if (dev
->bus
&& dev
->bus
->remove
)
890 dev
->bus
->remove(dev
);
891 else if (drv
->remove
)
894 device_links_driver_cleanup(dev
);
895 dma_deconfigure(dev
);
897 devres_release_all(dev
);
899 dev_set_drvdata(dev
, NULL
);
900 if (dev
->pm_domain
&& dev
->pm_domain
->dismiss
)
901 dev
->pm_domain
->dismiss(dev
);
902 pm_runtime_reinit(dev
);
903 dev_pm_set_driver_flags(dev
, 0);
905 klist_remove(&dev
->p
->knode_driver
);
906 device_pm_check_callbacks(dev
);
908 blocking_notifier_call_chain(&dev
->bus
->p
->bus_notifier
,
909 BUS_NOTIFY_UNBOUND_DRIVER
,
912 kobject_uevent(&dev
->kobj
, KOBJ_UNBIND
);
916 void device_release_driver_internal(struct device
*dev
,
917 struct device_driver
*drv
,
918 struct device
*parent
)
920 if (parent
&& dev
->bus
->need_parent_lock
)
924 if (!drv
|| drv
== dev
->driver
)
925 __device_release_driver(dev
, parent
);
928 if (parent
&& dev
->bus
->need_parent_lock
)
929 device_unlock(parent
);
933 * device_release_driver - manually detach device from driver.
936 * Manually detach device from driver.
937 * When called for a USB interface, @dev->parent lock must be held.
939 * If this function is to be called with @dev->parent lock held, ensure that
940 * the device's consumers are unbound in advance or that their locks can be
941 * acquired under the @dev->parent lock.
943 void device_release_driver(struct device
*dev
)
946 * If anyone calls device_release_driver() recursively from
947 * within their ->remove callback for the same device, they
948 * will deadlock right here.
950 device_release_driver_internal(dev
, NULL
, NULL
);
952 EXPORT_SYMBOL_GPL(device_release_driver
);
955 * driver_detach - detach driver from all devices it controls.
958 void driver_detach(struct device_driver
*drv
)
960 struct device_private
*dev_prv
;
964 spin_lock(&drv
->p
->klist_devices
.k_lock
);
965 if (list_empty(&drv
->p
->klist_devices
.k_list
)) {
966 spin_unlock(&drv
->p
->klist_devices
.k_lock
);
969 dev_prv
= list_entry(drv
->p
->klist_devices
.k_list
.prev
,
970 struct device_private
,
971 knode_driver
.n_node
);
972 dev
= dev_prv
->device
;
974 spin_unlock(&drv
->p
->klist_devices
.k_lock
);
975 device_release_driver_internal(dev
, drv
, dev
->parent
);