Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * drivers/base/dd.c - The core device/driver interactions.
4 : *
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.
8 : *
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'.
12 : *
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.
17 : */
18 :
19 : #include <linux/debugfs.h>
20 : #include <linux/device.h>
21 : #include <linux/delay.h>
22 : #include <linux/dma-map-ops.h>
23 : #include <linux/init.h>
24 : #include <linux/module.h>
25 : #include <linux/kthread.h>
26 : #include <linux/wait.h>
27 : #include <linux/async.h>
28 : #include <linux/pm_runtime.h>
29 : #include <linux/pinctrl/devinfo.h>
30 : #include <linux/slab.h>
31 :
32 : #include "base.h"
33 : #include "power/power.h"
34 :
35 : /*
36 : * Deferred Probe infrastructure.
37 : *
38 : * Sometimes driver probe order matters, but the kernel doesn't always have
39 : * dependency information which means some drivers will get probed before a
40 : * resource it depends on is available. For example, an SDHCI driver may
41 : * first need a GPIO line from an i2c GPIO controller before it can be
42 : * initialized. If a required resource is not available yet, a driver can
43 : * request probing to be deferred by returning -EPROBE_DEFER from its probe hook
44 : *
45 : * Deferred probe maintains two lists of devices, a pending list and an active
46 : * list. A driver returning -EPROBE_DEFER causes the device to be added to the
47 : * pending list. A successful driver probe will trigger moving all devices
48 : * from the pending to the active list so that the workqueue will eventually
49 : * retry them.
50 : *
51 : * The deferred_probe_mutex must be held any time the deferred_probe_*_list
52 : * of the (struct device*)->p->deferred_probe pointers are manipulated
53 : */
54 : static DEFINE_MUTEX(deferred_probe_mutex);
55 : static LIST_HEAD(deferred_probe_pending_list);
56 : static LIST_HEAD(deferred_probe_active_list);
57 : static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
58 : static bool initcalls_done;
59 :
60 : /* Save the async probe drivers' name from kernel cmdline */
61 : #define ASYNC_DRV_NAMES_MAX_LEN 256
62 : static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
63 : static bool async_probe_default;
64 :
65 : /*
66 : * In some cases, like suspend to RAM or hibernation, It might be reasonable
67 : * to prohibit probing of devices as it could be unsafe.
68 : * Once defer_all_probes is true all drivers probes will be forcibly deferred.
69 : */
70 : static bool defer_all_probes;
71 :
72 : static void __device_set_deferred_probe_reason(const struct device *dev, char *reason)
73 : {
74 0 : kfree(dev->p->deferred_probe_reason);
75 0 : dev->p->deferred_probe_reason = reason;
76 : }
77 :
78 : /*
79 : * deferred_probe_work_func() - Retry probing devices in the active list.
80 : */
81 7 : static void deferred_probe_work_func(struct work_struct *work)
82 : {
83 : struct device *dev;
84 : struct device_private *private;
85 : /*
86 : * This block processes every device in the deferred 'active' list.
87 : * Each device is removed from the active list and passed to
88 : * bus_probe_device() to re-attempt the probe. The loop continues
89 : * until every device in the active list is removed and retried.
90 : *
91 : * Note: Once the device is removed from the list and the mutex is
92 : * released, it is possible for the device get freed by another thread
93 : * and cause a illegal pointer dereference. This code uses
94 : * get/put_device() to ensure the device structure cannot disappear
95 : * from under our feet.
96 : */
97 7 : mutex_lock(&deferred_probe_mutex);
98 14 : while (!list_empty(&deferred_probe_active_list)) {
99 0 : private = list_first_entry(&deferred_probe_active_list,
100 : typeof(*dev->p), deferred_probe);
101 0 : dev = private->device;
102 0 : list_del_init(&private->deferred_probe);
103 :
104 0 : get_device(dev);
105 :
106 0 : __device_set_deferred_probe_reason(dev, NULL);
107 :
108 : /*
109 : * Drop the mutex while probing each device; the probe path may
110 : * manipulate the deferred list
111 : */
112 0 : mutex_unlock(&deferred_probe_mutex);
113 :
114 : /*
115 : * Force the device to the end of the dpm_list since
116 : * the PM code assumes that the order we add things to
117 : * the list is a good order for suspend but deferred
118 : * probe makes that very unsafe.
119 : */
120 0 : device_pm_move_to_tail(dev);
121 :
122 : dev_dbg(dev, "Retrying from deferred list\n");
123 0 : bus_probe_device(dev);
124 0 : mutex_lock(&deferred_probe_mutex);
125 :
126 0 : put_device(dev);
127 : }
128 7 : mutex_unlock(&deferred_probe_mutex);
129 7 : }
130 : static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
131 :
132 0 : void driver_deferred_probe_add(struct device *dev)
133 : {
134 0 : if (!dev->can_match)
135 : return;
136 :
137 0 : mutex_lock(&deferred_probe_mutex);
138 0 : if (list_empty(&dev->p->deferred_probe)) {
139 : dev_dbg(dev, "Added to deferred list\n");
140 0 : list_add_tail(&dev->p->deferred_probe, &deferred_probe_pending_list);
141 : }
142 0 : mutex_unlock(&deferred_probe_mutex);
143 : }
144 :
145 10 : void driver_deferred_probe_del(struct device *dev)
146 : {
147 10 : mutex_lock(&deferred_probe_mutex);
148 20 : if (!list_empty(&dev->p->deferred_probe)) {
149 : dev_dbg(dev, "Removed from deferred list\n");
150 0 : list_del_init(&dev->p->deferred_probe);
151 0 : __device_set_deferred_probe_reason(dev, NULL);
152 : }
153 10 : mutex_unlock(&deferred_probe_mutex);
154 10 : }
155 :
156 : static bool driver_deferred_probe_enable;
157 : /**
158 : * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
159 : *
160 : * This functions moves all devices from the pending list to the active
161 : * list and schedules the deferred probe workqueue to process them. It
162 : * should be called anytime a driver is successfully bound to a device.
163 : *
164 : * Note, there is a race condition in multi-threaded probe. In the case where
165 : * more than one device is probing at the same time, it is possible for one
166 : * probe to complete successfully while another is about to defer. If the second
167 : * depends on the first, then it will get put on the pending list after the
168 : * trigger event has already occurred and will be stuck there.
169 : *
170 : * The atomic 'deferred_trigger_count' is used to determine if a successful
171 : * trigger has occurred in the midst of probing a driver. If the trigger count
172 : * changes in the midst of a probe, then deferred processing should be triggered
173 : * again.
174 : */
175 7 : void driver_deferred_probe_trigger(void)
176 : {
177 7 : if (!driver_deferred_probe_enable)
178 : return;
179 :
180 : /*
181 : * A successful probe means that all the devices in the pending list
182 : * should be triggered to be reprobed. Move all the deferred devices
183 : * into the active list so they can be retried by the workqueue
184 : */
185 7 : mutex_lock(&deferred_probe_mutex);
186 7 : atomic_inc(&deferred_trigger_count);
187 7 : list_splice_tail_init(&deferred_probe_pending_list,
188 : &deferred_probe_active_list);
189 7 : mutex_unlock(&deferred_probe_mutex);
190 :
191 : /*
192 : * Kick the re-probe thread. It may already be scheduled, but it is
193 : * safe to kick it again.
194 : */
195 7 : queue_work(system_unbound_wq, &deferred_probe_work);
196 : }
197 :
198 : /**
199 : * device_block_probing() - Block/defer device's probes
200 : *
201 : * It will disable probing of devices and defer their probes instead.
202 : */
203 1 : void device_block_probing(void)
204 : {
205 1 : defer_all_probes = true;
206 : /* sync with probes to avoid races. */
207 1 : wait_for_device_probe();
208 1 : }
209 :
210 : /**
211 : * device_unblock_probing() - Unblock/enable device's probes
212 : *
213 : * It will restore normal behavior and trigger re-probing of deferred
214 : * devices.
215 : */
216 0 : void device_unblock_probing(void)
217 : {
218 0 : defer_all_probes = false;
219 0 : driver_deferred_probe_trigger();
220 0 : }
221 :
222 : /**
223 : * device_set_deferred_probe_reason() - Set defer probe reason message for device
224 : * @dev: the pointer to the struct device
225 : * @vaf: the pointer to va_format structure with message
226 : */
227 0 : void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf)
228 : {
229 0 : const char *drv = dev_driver_string(dev);
230 : char *reason;
231 :
232 0 : mutex_lock(&deferred_probe_mutex);
233 :
234 0 : reason = kasprintf(GFP_KERNEL, "%s: %pV", drv, vaf);
235 0 : __device_set_deferred_probe_reason(dev, reason);
236 :
237 0 : mutex_unlock(&deferred_probe_mutex);
238 0 : }
239 :
240 : /*
241 : * deferred_devs_show() - Show the devices in the deferred probe pending list.
242 : */
243 : static int deferred_devs_show(struct seq_file *s, void *data)
244 : {
245 : struct device_private *curr;
246 :
247 : mutex_lock(&deferred_probe_mutex);
248 :
249 : list_for_each_entry(curr, &deferred_probe_pending_list, deferred_probe)
250 : seq_printf(s, "%s\t%s", dev_name(curr->device),
251 : curr->device->p->deferred_probe_reason ?: "\n");
252 :
253 : mutex_unlock(&deferred_probe_mutex);
254 :
255 : return 0;
256 : }
257 : DEFINE_SHOW_ATTRIBUTE(deferred_devs);
258 :
259 : #ifdef CONFIG_MODULES
260 : static int driver_deferred_probe_timeout = 10;
261 : #else
262 : static int driver_deferred_probe_timeout;
263 : #endif
264 :
265 0 : static int __init deferred_probe_timeout_setup(char *str)
266 : {
267 : int timeout;
268 :
269 0 : if (!kstrtoint(str, 10, &timeout))
270 0 : driver_deferred_probe_timeout = timeout;
271 0 : return 1;
272 : }
273 : __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
274 :
275 : /**
276 : * driver_deferred_probe_check_state() - Check deferred probe state
277 : * @dev: device to check
278 : *
279 : * Return:
280 : * * -ENODEV if initcalls have completed and modules are disabled.
281 : * * -ETIMEDOUT if the deferred probe timeout was set and has expired
282 : * and modules are enabled.
283 : * * -EPROBE_DEFER in other cases.
284 : *
285 : * Drivers or subsystems can opt-in to calling this function instead of directly
286 : * returning -EPROBE_DEFER.
287 : */
288 0 : int driver_deferred_probe_check_state(struct device *dev)
289 : {
290 0 : if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done) {
291 0 : dev_warn(dev, "ignoring dependency for device, assuming no driver\n");
292 0 : return -ENODEV;
293 : }
294 :
295 : if (!driver_deferred_probe_timeout && initcalls_done) {
296 : dev_warn(dev, "deferred probe timeout, ignoring dependency\n");
297 : return -ETIMEDOUT;
298 : }
299 :
300 : return -EPROBE_DEFER;
301 : }
302 : EXPORT_SYMBOL_GPL(driver_deferred_probe_check_state);
303 :
304 0 : static void deferred_probe_timeout_work_func(struct work_struct *work)
305 : {
306 : struct device_private *p;
307 :
308 0 : fw_devlink_drivers_done();
309 :
310 0 : driver_deferred_probe_timeout = 0;
311 0 : driver_deferred_probe_trigger();
312 0 : flush_work(&deferred_probe_work);
313 :
314 0 : mutex_lock(&deferred_probe_mutex);
315 0 : list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe)
316 0 : dev_info(p->device, "deferred probe pending\n");
317 0 : mutex_unlock(&deferred_probe_mutex);
318 :
319 0 : fw_devlink_probing_done();
320 0 : }
321 : static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func);
322 :
323 21 : void deferred_probe_extend_timeout(void)
324 : {
325 : /*
326 : * If the work hasn't been queued yet or if the work expired, don't
327 : * start a new one.
328 : */
329 21 : if (cancel_delayed_work(&deferred_probe_timeout_work)) {
330 0 : schedule_delayed_work(&deferred_probe_timeout_work,
331 0 : driver_deferred_probe_timeout * HZ);
332 : pr_debug("Extended deferred probe timeout by %d secs\n",
333 : driver_deferred_probe_timeout);
334 : }
335 21 : }
336 :
337 : /**
338 : * deferred_probe_initcall() - Enable probing of deferred devices
339 : *
340 : * We don't want to get in the way when the bulk of drivers are getting probed.
341 : * Instead, this initcall makes sure that deferred probing is delayed until
342 : * late_initcall time.
343 : */
344 1 : static int deferred_probe_initcall(void)
345 : {
346 1 : debugfs_create_file("devices_deferred", 0444, NULL, NULL,
347 : &deferred_devs_fops);
348 :
349 1 : driver_deferred_probe_enable = true;
350 1 : driver_deferred_probe_trigger();
351 : /* Sort as many dependencies as possible before exiting initcalls */
352 1 : flush_work(&deferred_probe_work);
353 1 : initcalls_done = true;
354 :
355 : if (!IS_ENABLED(CONFIG_MODULES))
356 1 : fw_devlink_drivers_done();
357 :
358 : /*
359 : * Trigger deferred probe again, this time we won't defer anything
360 : * that is optional
361 : */
362 1 : driver_deferred_probe_trigger();
363 1 : flush_work(&deferred_probe_work);
364 :
365 1 : if (driver_deferred_probe_timeout > 0) {
366 0 : schedule_delayed_work(&deferred_probe_timeout_work,
367 0 : driver_deferred_probe_timeout * HZ);
368 : }
369 :
370 : if (!IS_ENABLED(CONFIG_MODULES))
371 1 : fw_devlink_probing_done();
372 :
373 1 : return 0;
374 : }
375 : late_initcall(deferred_probe_initcall);
376 :
377 0 : static void __exit deferred_probe_exit(void)
378 : {
379 0 : debugfs_lookup_and_remove("devices_deferred", NULL);
380 0 : }
381 : __exitcall(deferred_probe_exit);
382 :
383 : /**
384 : * device_is_bound() - Check if device is bound to a driver
385 : * @dev: device to check
386 : *
387 : * Returns true if passed device has already finished probing successfully
388 : * against a driver.
389 : *
390 : * This function must be called with the device lock held.
391 : */
392 0 : bool device_is_bound(struct device *dev)
393 : {
394 5 : return dev->p && klist_node_attached(&dev->p->knode_driver);
395 : }
396 :
397 5 : static void driver_bound(struct device *dev)
398 : {
399 5 : if (device_is_bound(dev)) {
400 0 : pr_warn("%s: device %s already bound\n",
401 : __func__, kobject_name(&dev->kobj));
402 0 : return;
403 : }
404 :
405 : pr_debug("driver: '%s': %s: bound to device '%s'\n", dev->driver->name,
406 : __func__, dev_name(dev));
407 :
408 5 : klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
409 5 : device_links_driver_bound(dev);
410 :
411 5 : device_pm_check_callbacks(dev);
412 :
413 : /*
414 : * Make sure the device is no longer in one of the deferred lists and
415 : * kick off retrying all pending devices
416 : */
417 5 : driver_deferred_probe_del(dev);
418 5 : driver_deferred_probe_trigger();
419 :
420 5 : bus_notify(dev, BUS_NOTIFY_BOUND_DRIVER);
421 5 : kobject_uevent(&dev->kobj, KOBJ_BIND);
422 : }
423 :
424 0 : static ssize_t coredump_store(struct device *dev, struct device_attribute *attr,
425 : const char *buf, size_t count)
426 : {
427 0 : device_lock(dev);
428 0 : dev->driver->coredump(dev);
429 0 : device_unlock(dev);
430 :
431 0 : return count;
432 : }
433 : static DEVICE_ATTR_WO(coredump);
434 :
435 5 : static int driver_sysfs_add(struct device *dev)
436 : {
437 : int ret;
438 :
439 5 : bus_notify(dev, BUS_NOTIFY_BIND_DRIVER);
440 :
441 5 : ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
442 5 : kobject_name(&dev->kobj));
443 5 : if (ret)
444 : goto fail;
445 :
446 5 : ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
447 : "driver");
448 5 : if (ret)
449 : goto rm_dev;
450 :
451 : if (!IS_ENABLED(CONFIG_DEV_COREDUMP) || !dev->driver->coredump)
452 : return 0;
453 :
454 : ret = device_create_file(dev, &dev_attr_coredump);
455 : if (!ret)
456 : return 0;
457 :
458 : sysfs_remove_link(&dev->kobj, "driver");
459 :
460 : rm_dev:
461 0 : sysfs_remove_link(&dev->driver->p->kobj,
462 0 : kobject_name(&dev->kobj));
463 :
464 : fail:
465 : return ret;
466 : }
467 :
468 5 : static void driver_sysfs_remove(struct device *dev)
469 : {
470 5 : struct device_driver *drv = dev->driver;
471 :
472 5 : if (drv) {
473 5 : if (drv->coredump)
474 0 : device_remove_file(dev, &dev_attr_coredump);
475 5 : sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
476 5 : sysfs_remove_link(&dev->kobj, "driver");
477 : }
478 5 : }
479 :
480 : /**
481 : * device_bind_driver - bind a driver to one device.
482 : * @dev: device.
483 : *
484 : * Allow manual attachment of a driver to a device.
485 : * Caller must have already set @dev->driver.
486 : *
487 : * Note that this does not modify the bus reference count.
488 : * Please verify that is accounted for before calling this.
489 : * (It is ok to call with no other effort from a driver's probe() method.)
490 : *
491 : * This function must be called with the device lock held.
492 : *
493 : * Callers should prefer to use device_driver_attach() instead.
494 : */
495 0 : int device_bind_driver(struct device *dev)
496 : {
497 : int ret;
498 :
499 0 : ret = driver_sysfs_add(dev);
500 0 : if (!ret) {
501 0 : device_links_force_bind(dev);
502 0 : driver_bound(dev);
503 : }
504 : else
505 0 : bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
506 0 : return ret;
507 : }
508 : EXPORT_SYMBOL_GPL(device_bind_driver);
509 :
510 : static atomic_t probe_count = ATOMIC_INIT(0);
511 : static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
512 :
513 0 : static ssize_t state_synced_store(struct device *dev,
514 : struct device_attribute *attr,
515 : const char *buf, size_t count)
516 : {
517 0 : int ret = 0;
518 :
519 0 : if (strcmp("1", buf))
520 : return -EINVAL;
521 :
522 0 : device_lock(dev);
523 0 : if (!dev->state_synced) {
524 0 : dev->state_synced = true;
525 0 : dev_sync_state(dev);
526 : } else {
527 : ret = -EINVAL;
528 : }
529 0 : device_unlock(dev);
530 :
531 0 : return ret ? ret : count;
532 : }
533 :
534 0 : static ssize_t state_synced_show(struct device *dev,
535 : struct device_attribute *attr, char *buf)
536 : {
537 : bool val;
538 :
539 0 : device_lock(dev);
540 0 : val = dev->state_synced;
541 0 : device_unlock(dev);
542 :
543 0 : return sysfs_emit(buf, "%u\n", val);
544 : }
545 : static DEVICE_ATTR_RW(state_synced);
546 :
547 5 : static void device_unbind_cleanup(struct device *dev)
548 : {
549 5 : devres_release_all(dev);
550 5 : arch_teardown_dma_ops(dev);
551 5 : kfree(dev->dma_range_map);
552 5 : dev->dma_range_map = NULL;
553 5 : dev->driver = NULL;
554 10 : dev_set_drvdata(dev, NULL);
555 5 : if (dev->pm_domain && dev->pm_domain->dismiss)
556 0 : dev->pm_domain->dismiss(dev);
557 5 : pm_runtime_reinit(dev);
558 10 : dev_pm_set_driver_flags(dev, 0);
559 5 : }
560 :
561 5 : static void device_remove(struct device *dev)
562 : {
563 5 : device_remove_file(dev, &dev_attr_state_synced);
564 5 : device_remove_groups(dev, dev->driver->dev_groups);
565 :
566 5 : if (dev->bus && dev->bus->remove)
567 5 : dev->bus->remove(dev);
568 0 : else if (dev->driver->remove)
569 0 : dev->driver->remove(dev);
570 5 : }
571 :
572 5 : static int call_driver_probe(struct device *dev, struct device_driver *drv)
573 : {
574 5 : int ret = 0;
575 :
576 5 : if (dev->bus->probe)
577 5 : ret = dev->bus->probe(dev);
578 0 : else if (drv->probe)
579 0 : ret = drv->probe(dev);
580 :
581 5 : switch (ret) {
582 : case 0:
583 : break;
584 : case -EPROBE_DEFER:
585 : /* Driver requested deferred probing */
586 : dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
587 : break;
588 : case -ENODEV:
589 : case -ENXIO:
590 : pr_debug("%s: probe of %s rejects match %d\n",
591 : drv->name, dev_name(dev), ret);
592 : break;
593 : default:
594 : /* driver matched but the probe failed */
595 0 : pr_warn("%s: probe of %s failed with error %d\n",
596 : drv->name, dev_name(dev), ret);
597 : break;
598 : }
599 :
600 5 : return ret;
601 : }
602 :
603 5 : static int really_probe(struct device *dev, struct device_driver *drv)
604 : {
605 5 : bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
606 : !drv->suppress_bind_attrs;
607 : int ret, link_ret;
608 :
609 5 : if (defer_all_probes) {
610 : /*
611 : * Value of defer_all_probes can be set only by
612 : * device_block_probing() which, in turn, will call
613 : * wait_for_device_probe() right after that to avoid any races.
614 : */
615 : dev_dbg(dev, "Driver %s force probe deferral\n", drv->name);
616 : return -EPROBE_DEFER;
617 : }
618 :
619 5 : link_ret = device_links_check_suppliers(dev);
620 5 : if (link_ret == -EPROBE_DEFER)
621 : return link_ret;
622 :
623 : pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
624 : drv->bus->name, __func__, drv->name, dev_name(dev));
625 10 : if (!list_empty(&dev->devres_head)) {
626 0 : dev_crit(dev, "Resources present before probing\n");
627 0 : ret = -EBUSY;
628 0 : goto done;
629 : }
630 :
631 : re_probe:
632 5 : dev->driver = drv;
633 :
634 : /* If using pinctrl, bind pins now before probing */
635 5 : ret = pinctrl_bind_pins(dev);
636 : if (ret)
637 : goto pinctrl_bind_failed;
638 :
639 5 : if (dev->bus->dma_configure) {
640 5 : ret = dev->bus->dma_configure(dev);
641 5 : if (ret)
642 : goto pinctrl_bind_failed;
643 : }
644 :
645 5 : ret = driver_sysfs_add(dev);
646 5 : if (ret) {
647 0 : pr_err("%s: driver_sysfs_add(%s) failed\n",
648 : __func__, dev_name(dev));
649 0 : goto sysfs_failed;
650 : }
651 :
652 5 : if (dev->pm_domain && dev->pm_domain->activate) {
653 0 : ret = dev->pm_domain->activate(dev);
654 0 : if (ret)
655 : goto probe_failed;
656 : }
657 :
658 5 : ret = call_driver_probe(dev, drv);
659 5 : if (ret) {
660 : /*
661 : * If fw_devlink_best_effort is active (denoted by -EAGAIN), the
662 : * device might actually probe properly once some of its missing
663 : * suppliers have probed. So, treat this as if the driver
664 : * returned -EPROBE_DEFER.
665 : */
666 0 : if (link_ret == -EAGAIN)
667 0 : ret = -EPROBE_DEFER;
668 :
669 : /*
670 : * Return probe errors as positive values so that the callers
671 : * can distinguish them from other errors.
672 : */
673 0 : ret = -ret;
674 0 : goto probe_failed;
675 : }
676 :
677 5 : ret = device_add_groups(dev, drv->dev_groups);
678 5 : if (ret) {
679 0 : dev_err(dev, "device_add_groups() failed\n");
680 0 : goto dev_groups_failed;
681 : }
682 :
683 5 : if (dev_has_sync_state(dev)) {
684 0 : ret = device_create_file(dev, &dev_attr_state_synced);
685 0 : if (ret) {
686 0 : dev_err(dev, "state_synced sysfs add failed\n");
687 0 : goto dev_sysfs_state_synced_failed;
688 : }
689 : }
690 :
691 : if (test_remove) {
692 : test_remove = false;
693 :
694 : device_remove(dev);
695 : driver_sysfs_remove(dev);
696 : device_unbind_cleanup(dev);
697 :
698 : goto re_probe;
699 : }
700 :
701 5 : pinctrl_init_done(dev);
702 :
703 5 : if (dev->pm_domain && dev->pm_domain->sync)
704 0 : dev->pm_domain->sync(dev);
705 :
706 5 : driver_bound(dev);
707 : pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
708 : drv->bus->name, __func__, dev_name(dev), drv->name);
709 5 : goto done;
710 :
711 : dev_sysfs_state_synced_failed:
712 : dev_groups_failed:
713 0 : device_remove(dev);
714 : probe_failed:
715 0 : driver_sysfs_remove(dev);
716 : sysfs_failed:
717 0 : bus_notify(dev, BUS_NOTIFY_DRIVER_NOT_BOUND);
718 0 : if (dev->bus && dev->bus->dma_cleanup)
719 0 : dev->bus->dma_cleanup(dev);
720 : pinctrl_bind_failed:
721 0 : device_links_no_driver(dev);
722 0 : device_unbind_cleanup(dev);
723 : done:
724 : return ret;
725 : }
726 :
727 : /*
728 : * For initcall_debug, show the driver probe time.
729 : */
730 0 : static int really_probe_debug(struct device *dev, struct device_driver *drv)
731 : {
732 : ktime_t calltime, rettime;
733 : int ret;
734 :
735 0 : calltime = ktime_get();
736 0 : ret = really_probe(dev, drv);
737 0 : rettime = ktime_get();
738 : /*
739 : * Don't change this to pr_debug() because that requires
740 : * CONFIG_DYNAMIC_DEBUG and we want a simple 'initcall_debug' on the
741 : * kernel commandline to print this all the time at the debug level.
742 : */
743 0 : printk(KERN_DEBUG "probe of %s returned %d after %lld usecs\n",
744 : dev_name(dev), ret, ktime_us_delta(rettime, calltime));
745 0 : return ret;
746 : }
747 :
748 : /**
749 : * driver_probe_done
750 : * Determine if the probe sequence is finished or not.
751 : *
752 : * Should somehow figure out how to use a semaphore, not an atomic variable...
753 : */
754 0 : bool __init driver_probe_done(void)
755 : {
756 0 : int local_probe_count = atomic_read(&probe_count);
757 :
758 : pr_debug("%s: probe_count = %d\n", __func__, local_probe_count);
759 0 : return !local_probe_count;
760 : }
761 :
762 : /**
763 : * wait_for_device_probe
764 : * Wait for device probing to be completed.
765 : */
766 2 : void wait_for_device_probe(void)
767 : {
768 : /* wait for the deferred probe workqueue to finish */
769 2 : flush_work(&deferred_probe_work);
770 :
771 : /* wait for the known devices to complete their probing */
772 2 : wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
773 2 : async_synchronize_full();
774 2 : }
775 : EXPORT_SYMBOL_GPL(wait_for_device_probe);
776 :
777 5 : static int __driver_probe_device(struct device_driver *drv, struct device *dev)
778 : {
779 5 : int ret = 0;
780 :
781 10 : if (dev->p->dead || !device_is_registered(dev))
782 : return -ENODEV;
783 5 : if (dev->driver)
784 : return -EBUSY;
785 :
786 5 : dev->can_match = true;
787 : pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
788 : drv->bus->name, __func__, dev_name(dev), drv->name);
789 :
790 5 : pm_runtime_get_suppliers(dev);
791 5 : if (dev->parent)
792 5 : pm_runtime_get_sync(dev->parent);
793 :
794 5 : pm_runtime_barrier(dev);
795 5 : if (initcall_debug)
796 0 : ret = really_probe_debug(dev, drv);
797 : else
798 5 : ret = really_probe(dev, drv);
799 5 : pm_request_idle(dev);
800 :
801 5 : if (dev->parent)
802 5 : pm_runtime_put(dev->parent);
803 :
804 5 : pm_runtime_put_suppliers(dev);
805 5 : return ret;
806 : }
807 :
808 : /**
809 : * driver_probe_device - attempt to bind device & driver together
810 : * @drv: driver to bind a device to
811 : * @dev: device to try to bind to the driver
812 : *
813 : * This function returns -ENODEV if the device is not registered, -EBUSY if it
814 : * already has a driver, 0 if the device is bound successfully and a positive
815 : * (inverted) error code for failures from the ->probe method.
816 : *
817 : * This function must be called with @dev lock held. When called for a
818 : * USB interface, @dev->parent lock must be held as well.
819 : *
820 : * If the device has a parent, runtime-resume the parent before driver probing.
821 : */
822 5 : static int driver_probe_device(struct device_driver *drv, struct device *dev)
823 : {
824 5 : int trigger_count = atomic_read(&deferred_trigger_count);
825 : int ret;
826 :
827 5 : atomic_inc(&probe_count);
828 5 : ret = __driver_probe_device(drv, dev);
829 5 : if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) {
830 0 : driver_deferred_probe_add(dev);
831 :
832 : /*
833 : * Did a trigger occur while probing? Need to re-trigger if yes
834 : */
835 0 : if (trigger_count != atomic_read(&deferred_trigger_count) &&
836 0 : !defer_all_probes)
837 0 : driver_deferred_probe_trigger();
838 : }
839 5 : atomic_dec(&probe_count);
840 5 : wake_up_all(&probe_waitqueue);
841 5 : return ret;
842 : }
843 :
844 : static inline bool cmdline_requested_async_probing(const char *drv_name)
845 : {
846 : bool async_drv;
847 :
848 11 : async_drv = parse_option_str(async_probe_drv_names, drv_name);
849 :
850 11 : return (async_probe_default != async_drv);
851 : }
852 :
853 : /* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
854 0 : static int __init save_async_options(char *buf)
855 : {
856 0 : if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
857 0 : pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
858 :
859 0 : strscpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
860 0 : async_probe_default = parse_option_str(async_probe_drv_names, "*");
861 :
862 0 : return 1;
863 : }
864 : __setup("driver_async_probe=", save_async_options);
865 :
866 11 : static bool driver_allows_async_probing(struct device_driver *drv)
867 : {
868 11 : switch (drv->probe_type) {
869 : case PROBE_PREFER_ASYNCHRONOUS:
870 : return true;
871 :
872 : case PROBE_FORCE_SYNCHRONOUS:
873 : return false;
874 :
875 : default:
876 22 : if (cmdline_requested_async_probing(drv->name))
877 : return true;
878 :
879 11 : if (module_requested_async_probing(drv->owner))
880 : return true;
881 :
882 : return false;
883 : }
884 : }
885 :
886 : struct device_attach_data {
887 : struct device *dev;
888 :
889 : /*
890 : * Indicates whether we are considering asynchronous probing or
891 : * not. Only initial binding after device or driver registration
892 : * (including deferral processing) may be done asynchronously, the
893 : * rest is always synchronous, as we expect it is being done by
894 : * request from userspace.
895 : */
896 : bool check_async;
897 :
898 : /*
899 : * Indicates if we are binding synchronous or asynchronous drivers.
900 : * When asynchronous probing is enabled we'll execute 2 passes
901 : * over drivers: first pass doing synchronous probing and second
902 : * doing asynchronous probing (if synchronous did not succeed -
903 : * most likely because there was no driver requiring synchronous
904 : * probing - and we found asynchronous driver during first pass).
905 : * The 2 passes are done because we can't shoot asynchronous
906 : * probe for given device and driver from bus_for_each_drv() since
907 : * driver pointer is not guaranteed to stay valid once
908 : * bus_for_each_drv() iterates to the next driver on the bus.
909 : */
910 : bool want_async;
911 :
912 : /*
913 : * We'll set have_async to 'true' if, while scanning for matching
914 : * driver, we'll encounter one that requests asynchronous probing.
915 : */
916 : bool have_async;
917 : };
918 :
919 15 : static int __device_attach_driver(struct device_driver *drv, void *_data)
920 : {
921 15 : struct device_attach_data *data = _data;
922 15 : struct device *dev = data->dev;
923 : bool async_allowed;
924 : int ret;
925 :
926 15 : ret = driver_match_device(drv, dev);
927 15 : if (ret == 0) {
928 : /* no match */
929 : return 0;
930 5 : } else if (ret == -EPROBE_DEFER) {
931 : dev_dbg(dev, "Device match requests probe deferral\n");
932 0 : dev->can_match = true;
933 0 : driver_deferred_probe_add(dev);
934 : /*
935 : * Device can't match with a driver right now, so don't attempt
936 : * to match or bind with other drivers on the bus.
937 : */
938 0 : return ret;
939 5 : } else if (ret < 0) {
940 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
941 : return ret;
942 : } /* ret > 0 means positive match */
943 :
944 5 : async_allowed = driver_allows_async_probing(drv);
945 :
946 5 : if (async_allowed)
947 0 : data->have_async = true;
948 :
949 5 : if (data->check_async && async_allowed != data->want_async)
950 : return 0;
951 :
952 : /*
953 : * Ignore errors returned by ->probe so that the next driver can try
954 : * its luck.
955 : */
956 5 : ret = driver_probe_device(drv, dev);
957 5 : if (ret < 0)
958 : return ret;
959 5 : return ret == 0;
960 : }
961 :
962 0 : static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
963 : {
964 0 : struct device *dev = _dev;
965 0 : struct device_attach_data data = {
966 : .dev = dev,
967 : .check_async = true,
968 : .want_async = true,
969 : };
970 :
971 0 : device_lock(dev);
972 :
973 : /*
974 : * Check if device has already been removed or claimed. This may
975 : * happen with driver loading, device discovery/registration,
976 : * and deferred probe processing happens all at once with
977 : * multiple threads.
978 : */
979 0 : if (dev->p->dead || dev->driver)
980 : goto out_unlock;
981 :
982 0 : if (dev->parent)
983 0 : pm_runtime_get_sync(dev->parent);
984 :
985 0 : bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
986 : dev_dbg(dev, "async probe completed\n");
987 :
988 0 : pm_request_idle(dev);
989 :
990 0 : if (dev->parent)
991 0 : pm_runtime_put(dev->parent);
992 : out_unlock:
993 0 : device_unlock(dev);
994 :
995 0 : put_device(dev);
996 0 : }
997 :
998 9 : static int __device_attach(struct device *dev, bool allow_async)
999 : {
1000 9 : int ret = 0;
1001 9 : bool async = false;
1002 :
1003 9 : device_lock(dev);
1004 9 : if (dev->p->dead) {
1005 : goto out_unlock;
1006 9 : } else if (dev->driver) {
1007 0 : if (device_is_bound(dev)) {
1008 : ret = 1;
1009 : goto out_unlock;
1010 : }
1011 0 : ret = device_bind_driver(dev);
1012 0 : if (ret == 0)
1013 : ret = 1;
1014 : else {
1015 0 : dev->driver = NULL;
1016 0 : ret = 0;
1017 : }
1018 : } else {
1019 9 : struct device_attach_data data = {
1020 : .dev = dev,
1021 : .check_async = allow_async,
1022 : .want_async = false,
1023 : };
1024 :
1025 9 : if (dev->parent)
1026 5 : pm_runtime_get_sync(dev->parent);
1027 :
1028 9 : ret = bus_for_each_drv(dev->bus, NULL, &data,
1029 : __device_attach_driver);
1030 9 : if (!ret && allow_async && data.have_async) {
1031 : /*
1032 : * If we could not find appropriate driver
1033 : * synchronously and we are allowed to do
1034 : * async probes and there are drivers that
1035 : * want to probe asynchronously, we'll
1036 : * try them.
1037 : */
1038 : dev_dbg(dev, "scheduling asynchronous probe\n");
1039 0 : get_device(dev);
1040 0 : async = true;
1041 : } else {
1042 : pm_request_idle(dev);
1043 : }
1044 :
1045 9 : if (dev->parent)
1046 5 : pm_runtime_put(dev->parent);
1047 : }
1048 : out_unlock:
1049 9 : device_unlock(dev);
1050 9 : if (async)
1051 : async_schedule_dev(__device_attach_async_helper, dev);
1052 9 : return ret;
1053 : }
1054 :
1055 : /**
1056 : * device_attach - try to attach device to a driver.
1057 : * @dev: device.
1058 : *
1059 : * Walk the list of drivers that the bus has and call
1060 : * driver_probe_device() for each pair. If a compatible
1061 : * pair is found, break out and return.
1062 : *
1063 : * Returns 1 if the device was bound to a driver;
1064 : * 0 if no matching driver was found;
1065 : * -ENODEV if the device is not registered.
1066 : *
1067 : * When called for a USB interface, @dev->parent lock must be held.
1068 : */
1069 0 : int device_attach(struct device *dev)
1070 : {
1071 0 : return __device_attach(dev, false);
1072 : }
1073 : EXPORT_SYMBOL_GPL(device_attach);
1074 :
1075 9 : void device_initial_probe(struct device *dev)
1076 : {
1077 9 : __device_attach(dev, true);
1078 9 : }
1079 :
1080 : /*
1081 : * __device_driver_lock - acquire locks needed to manipulate dev->drv
1082 : * @dev: Device we will update driver info for
1083 : * @parent: Parent device. Needed if the bus requires parent lock
1084 : *
1085 : * This function will take the required locks for manipulating dev->drv.
1086 : * Normally this will just be the @dev lock, but when called for a USB
1087 : * interface, @parent lock will be held as well.
1088 : */
1089 5 : static void __device_driver_lock(struct device *dev, struct device *parent)
1090 : {
1091 5 : if (parent && dev->bus->need_parent_lock)
1092 : device_lock(parent);
1093 5 : device_lock(dev);
1094 5 : }
1095 :
1096 : /*
1097 : * __device_driver_unlock - release locks needed to manipulate dev->drv
1098 : * @dev: Device we will update driver info for
1099 : * @parent: Parent device. Needed if the bus requires parent lock
1100 : *
1101 : * This function will release the required locks for manipulating dev->drv.
1102 : * Normally this will just be the @dev lock, but when called for a
1103 : * USB interface, @parent lock will be released as well.
1104 : */
1105 5 : static void __device_driver_unlock(struct device *dev, struct device *parent)
1106 : {
1107 5 : device_unlock(dev);
1108 5 : if (parent && dev->bus->need_parent_lock)
1109 : device_unlock(parent);
1110 5 : }
1111 :
1112 : /**
1113 : * device_driver_attach - attach a specific driver to a specific device
1114 : * @drv: Driver to attach
1115 : * @dev: Device to attach it to
1116 : *
1117 : * Manually attach driver to a device. Will acquire both @dev lock and
1118 : * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
1119 : */
1120 0 : int device_driver_attach(struct device_driver *drv, struct device *dev)
1121 : {
1122 : int ret;
1123 :
1124 0 : __device_driver_lock(dev, dev->parent);
1125 0 : ret = __driver_probe_device(drv, dev);
1126 0 : __device_driver_unlock(dev, dev->parent);
1127 :
1128 : /* also return probe errors as normal negative errnos */
1129 0 : if (ret > 0)
1130 0 : ret = -ret;
1131 0 : if (ret == -EPROBE_DEFER)
1132 : return -EAGAIN;
1133 0 : return ret;
1134 : }
1135 : EXPORT_SYMBOL_GPL(device_driver_attach);
1136 :
1137 0 : static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
1138 : {
1139 0 : struct device *dev = _dev;
1140 : struct device_driver *drv;
1141 : int ret;
1142 :
1143 0 : __device_driver_lock(dev, dev->parent);
1144 0 : drv = dev->p->async_driver;
1145 0 : dev->p->async_driver = NULL;
1146 0 : ret = driver_probe_device(drv, dev);
1147 0 : __device_driver_unlock(dev, dev->parent);
1148 :
1149 : dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
1150 :
1151 0 : put_device(dev);
1152 0 : }
1153 :
1154 0 : static int __driver_attach(struct device *dev, void *data)
1155 : {
1156 0 : struct device_driver *drv = data;
1157 0 : bool async = false;
1158 : int ret;
1159 :
1160 : /*
1161 : * Lock device and try to bind to it. We drop the error
1162 : * here and always return 0, because we need to keep trying
1163 : * to bind to devices and some drivers will return an error
1164 : * simply if it didn't support the device.
1165 : *
1166 : * driver_probe_device() will spit a warning if there
1167 : * is an error.
1168 : */
1169 :
1170 0 : ret = driver_match_device(drv, dev);
1171 0 : if (ret == 0) {
1172 : /* no match */
1173 : return 0;
1174 0 : } else if (ret == -EPROBE_DEFER) {
1175 : dev_dbg(dev, "Device match requests probe deferral\n");
1176 0 : dev->can_match = true;
1177 0 : driver_deferred_probe_add(dev);
1178 : /*
1179 : * Driver could not match with device, but may match with
1180 : * another device on the bus.
1181 : */
1182 0 : return 0;
1183 0 : } else if (ret < 0) {
1184 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1185 : /*
1186 : * Driver could not match with device, but may match with
1187 : * another device on the bus.
1188 : */
1189 : return 0;
1190 : } /* ret > 0 means positive match */
1191 :
1192 0 : if (driver_allows_async_probing(drv)) {
1193 : /*
1194 : * Instead of probing the device synchronously we will
1195 : * probe it asynchronously to allow for more parallelism.
1196 : *
1197 : * We only take the device lock here in order to guarantee
1198 : * that the dev->driver and async_driver fields are protected
1199 : */
1200 : dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
1201 0 : device_lock(dev);
1202 0 : if (!dev->driver && !dev->p->async_driver) {
1203 0 : get_device(dev);
1204 0 : dev->p->async_driver = drv;
1205 0 : async = true;
1206 : }
1207 0 : device_unlock(dev);
1208 0 : if (async)
1209 : async_schedule_dev(__driver_attach_async_helper, dev);
1210 : return 0;
1211 : }
1212 :
1213 0 : __device_driver_lock(dev, dev->parent);
1214 0 : driver_probe_device(drv, dev);
1215 0 : __device_driver_unlock(dev, dev->parent);
1216 :
1217 0 : return 0;
1218 : }
1219 :
1220 : /**
1221 : * driver_attach - try to bind driver to devices.
1222 : * @drv: driver.
1223 : *
1224 : * Walk the list of devices that the bus has on it and try to
1225 : * match the driver with each one. If driver_probe_device()
1226 : * returns 0 and the @dev->driver is set, we've found a
1227 : * compatible pair.
1228 : */
1229 23 : int driver_attach(struct device_driver *drv)
1230 : {
1231 23 : return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
1232 : }
1233 : EXPORT_SYMBOL_GPL(driver_attach);
1234 :
1235 : /*
1236 : * __device_release_driver() must be called with @dev lock held.
1237 : * When called for a USB interface, @dev->parent lock must be held as well.
1238 : */
1239 5 : static void __device_release_driver(struct device *dev, struct device *parent)
1240 : {
1241 : struct device_driver *drv;
1242 :
1243 5 : drv = dev->driver;
1244 5 : if (drv) {
1245 : pm_runtime_get_sync(dev);
1246 :
1247 5 : while (device_links_busy(dev)) {
1248 0 : __device_driver_unlock(dev, parent);
1249 :
1250 0 : device_links_unbind_consumers(dev);
1251 :
1252 0 : __device_driver_lock(dev, parent);
1253 : /*
1254 : * A concurrent invocation of the same function might
1255 : * have released the driver successfully while this one
1256 : * was waiting, so check for that.
1257 : */
1258 0 : if (dev->driver != drv) {
1259 : pm_runtime_put(dev);
1260 : return;
1261 : }
1262 : }
1263 :
1264 5 : driver_sysfs_remove(dev);
1265 :
1266 5 : bus_notify(dev, BUS_NOTIFY_UNBIND_DRIVER);
1267 :
1268 5 : pm_runtime_put_sync(dev);
1269 :
1270 5 : device_remove(dev);
1271 :
1272 5 : if (dev->bus && dev->bus->dma_cleanup)
1273 5 : dev->bus->dma_cleanup(dev);
1274 :
1275 5 : device_links_driver_cleanup(dev);
1276 5 : device_unbind_cleanup(dev);
1277 :
1278 5 : klist_remove(&dev->p->knode_driver);
1279 5 : device_pm_check_callbacks(dev);
1280 :
1281 5 : bus_notify(dev, BUS_NOTIFY_UNBOUND_DRIVER);
1282 5 : kobject_uevent(&dev->kobj, KOBJ_UNBIND);
1283 : }
1284 : }
1285 :
1286 5 : void device_release_driver_internal(struct device *dev,
1287 : struct device_driver *drv,
1288 : struct device *parent)
1289 : {
1290 5 : __device_driver_lock(dev, parent);
1291 :
1292 5 : if (!drv || drv == dev->driver)
1293 5 : __device_release_driver(dev, parent);
1294 :
1295 5 : __device_driver_unlock(dev, parent);
1296 5 : }
1297 :
1298 : /**
1299 : * device_release_driver - manually detach device from driver.
1300 : * @dev: device.
1301 : *
1302 : * Manually detach device from driver.
1303 : * When called for a USB interface, @dev->parent lock must be held.
1304 : *
1305 : * If this function is to be called with @dev->parent lock held, ensure that
1306 : * the device's consumers are unbound in advance or that their locks can be
1307 : * acquired under the @dev->parent lock.
1308 : */
1309 5 : void device_release_driver(struct device *dev)
1310 : {
1311 : /*
1312 : * If anyone calls device_release_driver() recursively from
1313 : * within their ->remove callback for the same device, they
1314 : * will deadlock right here.
1315 : */
1316 5 : device_release_driver_internal(dev, NULL, NULL);
1317 5 : }
1318 : EXPORT_SYMBOL_GPL(device_release_driver);
1319 :
1320 : /**
1321 : * device_driver_detach - detach driver from a specific device
1322 : * @dev: device to detach driver from
1323 : *
1324 : * Detach driver from device. Will acquire both @dev lock and @dev->parent
1325 : * lock if needed.
1326 : */
1327 0 : void device_driver_detach(struct device *dev)
1328 : {
1329 0 : device_release_driver_internal(dev, NULL, dev->parent);
1330 0 : }
1331 :
1332 : /**
1333 : * driver_detach - detach driver from all devices it controls.
1334 : * @drv: driver.
1335 : */
1336 6 : void driver_detach(struct device_driver *drv)
1337 : {
1338 : struct device_private *dev_prv;
1339 : struct device *dev;
1340 :
1341 6 : if (driver_allows_async_probing(drv))
1342 0 : async_synchronize_full();
1343 :
1344 : for (;;) {
1345 12 : spin_lock(&drv->p->klist_devices.k_lock);
1346 12 : if (list_empty(&drv->p->klist_devices.k_list)) {
1347 12 : spin_unlock(&drv->p->klist_devices.k_lock);
1348 : break;
1349 : }
1350 0 : dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
1351 : struct device_private,
1352 : knode_driver.n_node);
1353 0 : dev = dev_prv->device;
1354 0 : get_device(dev);
1355 0 : spin_unlock(&drv->p->klist_devices.k_lock);
1356 0 : device_release_driver_internal(dev, drv, dev->parent);
1357 0 : put_device(dev);
1358 : }
1359 6 : }
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