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 24 : 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 24 : mutex_lock(&deferred_probe_mutex);
98 48 : 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 24 : mutex_unlock(&deferred_probe_mutex);
129 24 : }
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 45 : void driver_deferred_probe_del(struct device *dev)
146 : {
147 45 : mutex_lock(&deferred_probe_mutex);
148 90 : 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 45 : mutex_unlock(&deferred_probe_mutex);
154 45 : }
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 24 : void driver_deferred_probe_trigger(void)
176 : {
177 24 : 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 24 : mutex_lock(&deferred_probe_mutex);
186 24 : atomic_inc(&deferred_trigger_count);
187 24 : list_splice_tail_init(&deferred_probe_pending_list,
188 : &deferred_probe_active_list);
189 24 : 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 24 : 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 38 : 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 38 : 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 38 : }
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 22 : return dev->p && klist_node_attached(&dev->p->knode_driver);
395 : }
396 :
397 22 : static void driver_bound(struct device *dev)
398 : {
399 22 : 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 22 : klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);
409 22 : device_links_driver_bound(dev);
410 :
411 22 : 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 22 : driver_deferred_probe_del(dev);
418 22 : driver_deferred_probe_trigger();
419 :
420 22 : bus_notify(dev, BUS_NOTIFY_BOUND_DRIVER);
421 22 : 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 22 : static int driver_sysfs_add(struct device *dev)
436 : {
437 : int ret;
438 :
439 22 : bus_notify(dev, BUS_NOTIFY_BIND_DRIVER);
440 :
441 22 : ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,
442 22 : kobject_name(&dev->kobj));
443 22 : if (ret)
444 : goto fail;
445 :
446 22 : ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,
447 : "driver");
448 22 : 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 22 : static void driver_sysfs_remove(struct device *dev)
469 : {
470 22 : struct device_driver *drv = dev->driver;
471 :
472 22 : if (drv) {
473 22 : if (drv->coredump)
474 0 : device_remove_file(dev, &dev_attr_coredump);
475 22 : sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
476 22 : sysfs_remove_link(&dev->kobj, "driver");
477 : }
478 22 : }
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 22 : static void device_unbind_cleanup(struct device *dev)
548 : {
549 22 : devres_release_all(dev);
550 22 : arch_teardown_dma_ops(dev);
551 22 : kfree(dev->dma_range_map);
552 22 : dev->dma_range_map = NULL;
553 22 : dev->driver = NULL;
554 44 : dev_set_drvdata(dev, NULL);
555 22 : if (dev->pm_domain && dev->pm_domain->dismiss)
556 0 : dev->pm_domain->dismiss(dev);
557 22 : pm_runtime_reinit(dev);
558 44 : dev_pm_set_driver_flags(dev, 0);
559 22 : }
560 :
561 22 : static void device_remove(struct device *dev)
562 : {
563 22 : device_remove_file(dev, &dev_attr_state_synced);
564 22 : device_remove_groups(dev, dev->driver->dev_groups);
565 :
566 22 : if (dev->bus && dev->bus->remove)
567 22 : dev->bus->remove(dev);
568 0 : else if (dev->driver->remove)
569 0 : dev->driver->remove(dev);
570 22 : }
571 :
572 22 : static int call_driver_probe(struct device *dev, struct device_driver *drv)
573 : {
574 22 : int ret = 0;
575 :
576 22 : if (dev->bus->probe)
577 22 : ret = dev->bus->probe(dev);
578 0 : else if (drv->probe)
579 0 : ret = drv->probe(dev);
580 :
581 22 : 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 22 : return ret;
601 : }
602 :
603 22 : static int really_probe(struct device *dev, struct device_driver *drv)
604 : {
605 22 : bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
606 : !drv->suppress_bind_attrs;
607 : int ret, link_ret;
608 :
609 22 : 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 22 : link_ret = device_links_check_suppliers(dev);
620 22 : 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 44 : 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 22 : dev->driver = drv;
633 :
634 : /* If using pinctrl, bind pins now before probing */
635 22 : ret = pinctrl_bind_pins(dev);
636 : if (ret)
637 : goto pinctrl_bind_failed;
638 :
639 22 : if (dev->bus->dma_configure) {
640 22 : ret = dev->bus->dma_configure(dev);
641 22 : if (ret)
642 : goto pinctrl_bind_failed;
643 : }
644 :
645 22 : ret = driver_sysfs_add(dev);
646 22 : 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 22 : 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 22 : ret = call_driver_probe(dev, drv);
659 22 : 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 22 : ret = device_add_groups(dev, drv->dev_groups);
678 22 : if (ret) {
679 0 : dev_err(dev, "device_add_groups() failed\n");
680 0 : goto dev_groups_failed;
681 : }
682 :
683 22 : 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 22 : pinctrl_init_done(dev);
702 :
703 22 : if (dev->pm_domain && dev->pm_domain->sync)
704 0 : dev->pm_domain->sync(dev);
705 :
706 22 : 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 22 : 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 : int 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 : if (local_probe_count)
760 : return -EBUSY;
761 0 : return 0;
762 : }
763 :
764 : /**
765 : * wait_for_device_probe
766 : * Wait for device probing to be completed.
767 : */
768 2 : void wait_for_device_probe(void)
769 : {
770 : /* wait for the deferred probe workqueue to finish */
771 2 : flush_work(&deferred_probe_work);
772 :
773 : /* wait for the known devices to complete their probing */
774 2 : wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);
775 2 : async_synchronize_full();
776 2 : }
777 : EXPORT_SYMBOL_GPL(wait_for_device_probe);
778 :
779 22 : static int __driver_probe_device(struct device_driver *drv, struct device *dev)
780 : {
781 22 : int ret = 0;
782 :
783 44 : if (dev->p->dead || !device_is_registered(dev))
784 : return -ENODEV;
785 22 : if (dev->driver)
786 : return -EBUSY;
787 :
788 22 : dev->can_match = true;
789 : pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
790 : drv->bus->name, __func__, dev_name(dev), drv->name);
791 :
792 22 : pm_runtime_get_suppliers(dev);
793 22 : if (dev->parent)
794 22 : pm_runtime_get_sync(dev->parent);
795 :
796 22 : pm_runtime_barrier(dev);
797 22 : if (initcall_debug)
798 0 : ret = really_probe_debug(dev, drv);
799 : else
800 22 : ret = really_probe(dev, drv);
801 22 : pm_request_idle(dev);
802 :
803 22 : if (dev->parent)
804 22 : pm_runtime_put(dev->parent);
805 :
806 22 : pm_runtime_put_suppliers(dev);
807 22 : return ret;
808 : }
809 :
810 : /**
811 : * driver_probe_device - attempt to bind device & driver together
812 : * @drv: driver to bind a device to
813 : * @dev: device to try to bind to the driver
814 : *
815 : * This function returns -ENODEV if the device is not registered, -EBUSY if it
816 : * already has a driver, 0 if the device is bound successfully and a positive
817 : * (inverted) error code for failures from the ->probe method.
818 : *
819 : * This function must be called with @dev lock held. When called for a
820 : * USB interface, @dev->parent lock must be held as well.
821 : *
822 : * If the device has a parent, runtime-resume the parent before driver probing.
823 : */
824 22 : static int driver_probe_device(struct device_driver *drv, struct device *dev)
825 : {
826 22 : int trigger_count = atomic_read(&deferred_trigger_count);
827 : int ret;
828 :
829 22 : atomic_inc(&probe_count);
830 22 : ret = __driver_probe_device(drv, dev);
831 22 : if (ret == -EPROBE_DEFER || ret == EPROBE_DEFER) {
832 0 : driver_deferred_probe_add(dev);
833 :
834 : /*
835 : * Did a trigger occur while probing? Need to re-trigger if yes
836 : */
837 0 : if (trigger_count != atomic_read(&deferred_trigger_count) &&
838 0 : !defer_all_probes)
839 0 : driver_deferred_probe_trigger();
840 : }
841 22 : atomic_dec(&probe_count);
842 22 : wake_up_all(&probe_waitqueue);
843 22 : return ret;
844 : }
845 :
846 : static inline bool cmdline_requested_async_probing(const char *drv_name)
847 : {
848 : bool async_drv;
849 :
850 45 : async_drv = parse_option_str(async_probe_drv_names, drv_name);
851 :
852 45 : return (async_probe_default != async_drv);
853 : }
854 :
855 : /* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
856 0 : static int __init save_async_options(char *buf)
857 : {
858 0 : if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
859 0 : pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
860 :
861 0 : strscpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
862 0 : async_probe_default = parse_option_str(async_probe_drv_names, "*");
863 :
864 0 : return 1;
865 : }
866 : __setup("driver_async_probe=", save_async_options);
867 :
868 45 : static bool driver_allows_async_probing(struct device_driver *drv)
869 : {
870 45 : switch (drv->probe_type) {
871 : case PROBE_PREFER_ASYNCHRONOUS:
872 : return true;
873 :
874 : case PROBE_FORCE_SYNCHRONOUS:
875 : return false;
876 :
877 : default:
878 90 : if (cmdline_requested_async_probing(drv->name))
879 : return true;
880 :
881 45 : if (module_requested_async_probing(drv->owner))
882 : return true;
883 :
884 : return false;
885 : }
886 : }
887 :
888 : struct device_attach_data {
889 : struct device *dev;
890 :
891 : /*
892 : * Indicates whether we are considering asynchronous probing or
893 : * not. Only initial binding after device or driver registration
894 : * (including deferral processing) may be done asynchronously, the
895 : * rest is always synchronous, as we expect it is being done by
896 : * request from userspace.
897 : */
898 : bool check_async;
899 :
900 : /*
901 : * Indicates if we are binding synchronous or asynchronous drivers.
902 : * When asynchronous probing is enabled we'll execute 2 passes
903 : * over drivers: first pass doing synchronous probing and second
904 : * doing asynchronous probing (if synchronous did not succeed -
905 : * most likely because there was no driver requiring synchronous
906 : * probing - and we found asynchronous driver during first pass).
907 : * The 2 passes are done because we can't shoot asynchronous
908 : * probe for given device and driver from bus_for_each_drv() since
909 : * driver pointer is not guaranteed to stay valid once
910 : * bus_for_each_drv() iterates to the next driver on the bus.
911 : */
912 : bool want_async;
913 :
914 : /*
915 : * We'll set have_async to 'true' if, while scanning for matching
916 : * driver, we'll encounter one that requests asynchronous probing.
917 : */
918 : bool have_async;
919 : };
920 :
921 66 : static int __device_attach_driver(struct device_driver *drv, void *_data)
922 : {
923 66 : struct device_attach_data *data = _data;
924 66 : struct device *dev = data->dev;
925 : bool async_allowed;
926 : int ret;
927 :
928 66 : ret = driver_match_device(drv, dev);
929 66 : if (ret == 0) {
930 : /* no match */
931 : return 0;
932 22 : } else if (ret == -EPROBE_DEFER) {
933 : dev_dbg(dev, "Device match requests probe deferral\n");
934 0 : dev->can_match = true;
935 0 : driver_deferred_probe_add(dev);
936 : /*
937 : * Device can't match with a driver right now, so don't attempt
938 : * to match or bind with other drivers on the bus.
939 : */
940 0 : return ret;
941 22 : } else if (ret < 0) {
942 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
943 : return ret;
944 : } /* ret > 0 means positive match */
945 :
946 22 : async_allowed = driver_allows_async_probing(drv);
947 :
948 22 : if (async_allowed)
949 0 : data->have_async = true;
950 :
951 22 : if (data->check_async && async_allowed != data->want_async)
952 : return 0;
953 :
954 : /*
955 : * Ignore errors returned by ->probe so that the next driver can try
956 : * its luck.
957 : */
958 22 : ret = driver_probe_device(drv, dev);
959 22 : if (ret < 0)
960 : return ret;
961 22 : return ret == 0;
962 : }
963 :
964 0 : static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
965 : {
966 0 : struct device *dev = _dev;
967 0 : struct device_attach_data data = {
968 : .dev = dev,
969 : .check_async = true,
970 : .want_async = true,
971 : };
972 :
973 0 : device_lock(dev);
974 :
975 : /*
976 : * Check if device has already been removed or claimed. This may
977 : * happen with driver loading, device discovery/registration,
978 : * and deferred probe processing happens all at once with
979 : * multiple threads.
980 : */
981 0 : if (dev->p->dead || dev->driver)
982 : goto out_unlock;
983 :
984 0 : if (dev->parent)
985 0 : pm_runtime_get_sync(dev->parent);
986 :
987 0 : bus_for_each_drv(dev->bus, NULL, &data, __device_attach_driver);
988 : dev_dbg(dev, "async probe completed\n");
989 :
990 0 : pm_request_idle(dev);
991 :
992 0 : if (dev->parent)
993 0 : pm_runtime_put(dev->parent);
994 : out_unlock:
995 0 : device_unlock(dev);
996 :
997 0 : put_device(dev);
998 0 : }
999 :
1000 26 : static int __device_attach(struct device *dev, bool allow_async)
1001 : {
1002 26 : int ret = 0;
1003 26 : bool async = false;
1004 :
1005 26 : device_lock(dev);
1006 26 : if (dev->p->dead) {
1007 : goto out_unlock;
1008 26 : } else if (dev->driver) {
1009 0 : if (device_is_bound(dev)) {
1010 : ret = 1;
1011 : goto out_unlock;
1012 : }
1013 0 : ret = device_bind_driver(dev);
1014 0 : if (ret == 0)
1015 : ret = 1;
1016 : else {
1017 0 : dev->driver = NULL;
1018 0 : ret = 0;
1019 : }
1020 : } else {
1021 26 : struct device_attach_data data = {
1022 : .dev = dev,
1023 : .check_async = allow_async,
1024 : .want_async = false,
1025 : };
1026 :
1027 26 : if (dev->parent)
1028 22 : pm_runtime_get_sync(dev->parent);
1029 :
1030 26 : ret = bus_for_each_drv(dev->bus, NULL, &data,
1031 : __device_attach_driver);
1032 26 : if (!ret && allow_async && data.have_async) {
1033 : /*
1034 : * If we could not find appropriate driver
1035 : * synchronously and we are allowed to do
1036 : * async probes and there are drivers that
1037 : * want to probe asynchronously, we'll
1038 : * try them.
1039 : */
1040 : dev_dbg(dev, "scheduling asynchronous probe\n");
1041 0 : get_device(dev);
1042 0 : async = true;
1043 : } else {
1044 : pm_request_idle(dev);
1045 : }
1046 :
1047 26 : if (dev->parent)
1048 22 : pm_runtime_put(dev->parent);
1049 : }
1050 : out_unlock:
1051 26 : device_unlock(dev);
1052 26 : if (async)
1053 : async_schedule_dev(__device_attach_async_helper, dev);
1054 26 : return ret;
1055 : }
1056 :
1057 : /**
1058 : * device_attach - try to attach device to a driver.
1059 : * @dev: device.
1060 : *
1061 : * Walk the list of drivers that the bus has and call
1062 : * driver_probe_device() for each pair. If a compatible
1063 : * pair is found, break out and return.
1064 : *
1065 : * Returns 1 if the device was bound to a driver;
1066 : * 0 if no matching driver was found;
1067 : * -ENODEV if the device is not registered.
1068 : *
1069 : * When called for a USB interface, @dev->parent lock must be held.
1070 : */
1071 0 : int device_attach(struct device *dev)
1072 : {
1073 0 : return __device_attach(dev, false);
1074 : }
1075 : EXPORT_SYMBOL_GPL(device_attach);
1076 :
1077 26 : void device_initial_probe(struct device *dev)
1078 : {
1079 26 : __device_attach(dev, true);
1080 26 : }
1081 :
1082 : /*
1083 : * __device_driver_lock - acquire locks needed to manipulate dev->drv
1084 : * @dev: Device we will update driver info for
1085 : * @parent: Parent device. Needed if the bus requires parent lock
1086 : *
1087 : * This function will take the required locks for manipulating dev->drv.
1088 : * Normally this will just be the @dev lock, but when called for a USB
1089 : * interface, @parent lock will be held as well.
1090 : */
1091 22 : static void __device_driver_lock(struct device *dev, struct device *parent)
1092 : {
1093 22 : if (parent && dev->bus->need_parent_lock)
1094 : device_lock(parent);
1095 22 : device_lock(dev);
1096 22 : }
1097 :
1098 : /*
1099 : * __device_driver_unlock - release locks needed to manipulate dev->drv
1100 : * @dev: Device we will update driver info for
1101 : * @parent: Parent device. Needed if the bus requires parent lock
1102 : *
1103 : * This function will release the required locks for manipulating dev->drv.
1104 : * Normally this will just be the @dev lock, but when called for a
1105 : * USB interface, @parent lock will be released as well.
1106 : */
1107 22 : static void __device_driver_unlock(struct device *dev, struct device *parent)
1108 : {
1109 22 : device_unlock(dev);
1110 22 : if (parent && dev->bus->need_parent_lock)
1111 : device_unlock(parent);
1112 22 : }
1113 :
1114 : /**
1115 : * device_driver_attach - attach a specific driver to a specific device
1116 : * @drv: Driver to attach
1117 : * @dev: Device to attach it to
1118 : *
1119 : * Manually attach driver to a device. Will acquire both @dev lock and
1120 : * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
1121 : */
1122 0 : int device_driver_attach(struct device_driver *drv, struct device *dev)
1123 : {
1124 : int ret;
1125 :
1126 0 : __device_driver_lock(dev, dev->parent);
1127 0 : ret = __driver_probe_device(drv, dev);
1128 0 : __device_driver_unlock(dev, dev->parent);
1129 :
1130 : /* also return probe errors as normal negative errnos */
1131 0 : if (ret > 0)
1132 0 : ret = -ret;
1133 0 : if (ret == -EPROBE_DEFER)
1134 : return -EAGAIN;
1135 0 : return ret;
1136 : }
1137 : EXPORT_SYMBOL_GPL(device_driver_attach);
1138 :
1139 0 : static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
1140 : {
1141 0 : struct device *dev = _dev;
1142 : struct device_driver *drv;
1143 : int ret;
1144 :
1145 0 : __device_driver_lock(dev, dev->parent);
1146 0 : drv = dev->p->async_driver;
1147 0 : dev->p->async_driver = NULL;
1148 0 : ret = driver_probe_device(drv, dev);
1149 0 : __device_driver_unlock(dev, dev->parent);
1150 :
1151 : dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
1152 :
1153 0 : put_device(dev);
1154 0 : }
1155 :
1156 0 : static int __driver_attach(struct device *dev, void *data)
1157 : {
1158 0 : struct device_driver *drv = data;
1159 0 : bool async = false;
1160 : int ret;
1161 :
1162 : /*
1163 : * Lock device and try to bind to it. We drop the error
1164 : * here and always return 0, because we need to keep trying
1165 : * to bind to devices and some drivers will return an error
1166 : * simply if it didn't support the device.
1167 : *
1168 : * driver_probe_device() will spit a warning if there
1169 : * is an error.
1170 : */
1171 :
1172 0 : ret = driver_match_device(drv, dev);
1173 0 : if (ret == 0) {
1174 : /* no match */
1175 : return 0;
1176 0 : } else if (ret == -EPROBE_DEFER) {
1177 : dev_dbg(dev, "Device match requests probe deferral\n");
1178 0 : dev->can_match = true;
1179 0 : driver_deferred_probe_add(dev);
1180 : /*
1181 : * Driver could not match with device, but may match with
1182 : * another device on the bus.
1183 : */
1184 0 : return 0;
1185 0 : } else if (ret < 0) {
1186 : dev_dbg(dev, "Bus failed to match device: %d\n", ret);
1187 : /*
1188 : * Driver could not match with device, but may match with
1189 : * another device on the bus.
1190 : */
1191 : return 0;
1192 : } /* ret > 0 means positive match */
1193 :
1194 0 : if (driver_allows_async_probing(drv)) {
1195 : /*
1196 : * Instead of probing the device synchronously we will
1197 : * probe it asynchronously to allow for more parallelism.
1198 : *
1199 : * We only take the device lock here in order to guarantee
1200 : * that the dev->driver and async_driver fields are protected
1201 : */
1202 : dev_dbg(dev, "probing driver %s asynchronously\n", drv->name);
1203 0 : device_lock(dev);
1204 0 : if (!dev->driver && !dev->p->async_driver) {
1205 0 : get_device(dev);
1206 0 : dev->p->async_driver = drv;
1207 0 : async = true;
1208 : }
1209 0 : device_unlock(dev);
1210 0 : if (async)
1211 : async_schedule_dev(__driver_attach_async_helper, dev);
1212 : return 0;
1213 : }
1214 :
1215 0 : __device_driver_lock(dev, dev->parent);
1216 0 : driver_probe_device(drv, dev);
1217 0 : __device_driver_unlock(dev, dev->parent);
1218 :
1219 0 : return 0;
1220 : }
1221 :
1222 : /**
1223 : * driver_attach - try to bind driver to devices.
1224 : * @drv: driver.
1225 : *
1226 : * Walk the list of devices that the bus has on it and try to
1227 : * match the driver with each one. If driver_probe_device()
1228 : * returns 0 and the @dev->driver is set, we've found a
1229 : * compatible pair.
1230 : */
1231 40 : int driver_attach(struct device_driver *drv)
1232 : {
1233 40 : return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
1234 : }
1235 : EXPORT_SYMBOL_GPL(driver_attach);
1236 :
1237 : /*
1238 : * __device_release_driver() must be called with @dev lock held.
1239 : * When called for a USB interface, @dev->parent lock must be held as well.
1240 : */
1241 22 : static void __device_release_driver(struct device *dev, struct device *parent)
1242 : {
1243 : struct device_driver *drv;
1244 :
1245 22 : drv = dev->driver;
1246 22 : if (drv) {
1247 : pm_runtime_get_sync(dev);
1248 :
1249 22 : while (device_links_busy(dev)) {
1250 0 : __device_driver_unlock(dev, parent);
1251 :
1252 0 : device_links_unbind_consumers(dev);
1253 :
1254 0 : __device_driver_lock(dev, parent);
1255 : /*
1256 : * A concurrent invocation of the same function might
1257 : * have released the driver successfully while this one
1258 : * was waiting, so check for that.
1259 : */
1260 0 : if (dev->driver != drv) {
1261 : pm_runtime_put(dev);
1262 : return;
1263 : }
1264 : }
1265 :
1266 22 : driver_sysfs_remove(dev);
1267 :
1268 22 : bus_notify(dev, BUS_NOTIFY_UNBIND_DRIVER);
1269 :
1270 22 : pm_runtime_put_sync(dev);
1271 :
1272 22 : device_remove(dev);
1273 :
1274 22 : if (dev->bus && dev->bus->dma_cleanup)
1275 22 : dev->bus->dma_cleanup(dev);
1276 :
1277 22 : device_links_driver_cleanup(dev);
1278 22 : device_unbind_cleanup(dev);
1279 :
1280 22 : klist_remove(&dev->p->knode_driver);
1281 22 : device_pm_check_callbacks(dev);
1282 :
1283 22 : bus_notify(dev, BUS_NOTIFY_UNBOUND_DRIVER);
1284 22 : kobject_uevent(&dev->kobj, KOBJ_UNBIND);
1285 : }
1286 : }
1287 :
1288 22 : void device_release_driver_internal(struct device *dev,
1289 : struct device_driver *drv,
1290 : struct device *parent)
1291 : {
1292 22 : __device_driver_lock(dev, parent);
1293 :
1294 22 : if (!drv || drv == dev->driver)
1295 22 : __device_release_driver(dev, parent);
1296 :
1297 22 : __device_driver_unlock(dev, parent);
1298 22 : }
1299 :
1300 : /**
1301 : * device_release_driver - manually detach device from driver.
1302 : * @dev: device.
1303 : *
1304 : * Manually detach device from driver.
1305 : * When called for a USB interface, @dev->parent lock must be held.
1306 : *
1307 : * If this function is to be called with @dev->parent lock held, ensure that
1308 : * the device's consumers are unbound in advance or that their locks can be
1309 : * acquired under the @dev->parent lock.
1310 : */
1311 22 : void device_release_driver(struct device *dev)
1312 : {
1313 : /*
1314 : * If anyone calls device_release_driver() recursively from
1315 : * within their ->remove callback for the same device, they
1316 : * will deadlock right here.
1317 : */
1318 22 : device_release_driver_internal(dev, NULL, NULL);
1319 22 : }
1320 : EXPORT_SYMBOL_GPL(device_release_driver);
1321 :
1322 : /**
1323 : * device_driver_detach - detach driver from a specific device
1324 : * @dev: device to detach driver from
1325 : *
1326 : * Detach driver from device. Will acquire both @dev lock and @dev->parent
1327 : * lock if needed.
1328 : */
1329 0 : void device_driver_detach(struct device *dev)
1330 : {
1331 0 : device_release_driver_internal(dev, NULL, dev->parent);
1332 0 : }
1333 :
1334 : /**
1335 : * driver_detach - detach driver from all devices it controls.
1336 : * @drv: driver.
1337 : */
1338 23 : void driver_detach(struct device_driver *drv)
1339 : {
1340 : struct device_private *dev_prv;
1341 : struct device *dev;
1342 :
1343 23 : if (driver_allows_async_probing(drv))
1344 0 : async_synchronize_full();
1345 :
1346 : for (;;) {
1347 46 : spin_lock(&drv->p->klist_devices.k_lock);
1348 46 : if (list_empty(&drv->p->klist_devices.k_list)) {
1349 46 : spin_unlock(&drv->p->klist_devices.k_lock);
1350 : break;
1351 : }
1352 0 : dev_prv = list_last_entry(&drv->p->klist_devices.k_list,
1353 : struct device_private,
1354 : knode_driver.n_node);
1355 0 : dev = dev_prv->device;
1356 0 : get_device(dev);
1357 0 : spin_unlock(&drv->p->klist_devices.k_lock);
1358 0 : device_release_driver_internal(dev, drv, dev->parent);
1359 0 : put_device(dev);
1360 : }
1361 23 : }
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