Line data Source code
1 : /* Kernel thread helper functions.
2 : * Copyright (C) 2004 IBM Corporation, Rusty Russell.
3 : *
4 : * Creation is done via kthreadd, so that we get a clean environment
5 : * even if we're invoked from userspace (think modprobe, hotplug cpu,
6 : * etc.).
7 : */
8 : #include <linux/sched.h>
9 : #include <linux/kthread.h>
10 : #include <linux/completion.h>
11 : #include <linux/err.h>
12 : #include <linux/cpuset.h>
13 : #include <linux/unistd.h>
14 : #include <linux/file.h>
15 : #include <linux/export.h>
16 : #include <linux/mutex.h>
17 : #include <linux/slab.h>
18 : #include <linux/freezer.h>
19 : #include <linux/ptrace.h>
20 : #include <linux/uaccess.h>
21 : #include <trace/events/sched.h>
22 :
23 : static DEFINE_SPINLOCK(kthread_create_lock);
24 : static LIST_HEAD(kthread_create_list);
25 : struct task_struct *kthreadd_task;
26 :
27 : struct kthread_create_info
28 : {
29 : /* Information passed to kthread() from kthreadd. */
30 : int (*threadfn)(void *data);
31 : void *data;
32 : int node;
33 :
34 : /* Result passed back to kthread_create() from kthreadd. */
35 : struct task_struct *result;
36 : struct completion *done;
37 :
38 : struct list_head list;
39 : };
40 :
41 : struct kthread {
42 : unsigned long flags;
43 : unsigned int cpu;
44 : void *data;
45 : struct completion parked;
46 : struct completion exited;
47 : };
48 :
49 : enum KTHREAD_BITS {
50 : KTHREAD_IS_PER_CPU = 0,
51 : KTHREAD_SHOULD_STOP,
52 : KTHREAD_SHOULD_PARK,
53 : KTHREAD_IS_PARKED,
54 : };
55 :
56 : #define __to_kthread(vfork) \
57 : container_of(vfork, struct kthread, exited)
58 :
59 : static inline struct kthread *to_kthread(struct task_struct *k)
60 : {
61 448480 : return __to_kthread(k->vfork_done);
62 : }
63 :
64 : static struct kthread *to_live_kthread(struct task_struct *k)
65 : {
66 2 : struct completion *vfork = ACCESS_ONCE(k->vfork_done);
67 2 : if (likely(vfork))
68 2 : return __to_kthread(vfork);
69 : return NULL;
70 : }
71 :
72 : /**
73 : * kthread_should_stop - should this kthread return now?
74 : *
75 : * When someone calls kthread_stop() on your kthread, it will be woken
76 : * and this will return true. You should then return, and your return
77 : * value will be passed through to kthread_stop().
78 : */
79 182826 : bool kthread_should_stop(void)
80 : {
81 365652 : return test_bit(KTHREAD_SHOULD_STOP, &to_kthread(current)->flags);
82 : }
83 : EXPORT_SYMBOL(kthread_should_stop);
84 :
85 : /**
86 : * kthread_should_park - should this kthread park now?
87 : *
88 : * When someone calls kthread_park() on your kthread, it will be woken
89 : * and this will return true. You should then do the necessary
90 : * cleanup and call kthread_parkme()
91 : *
92 : * Similar to kthread_should_stop(), but this keeps the thread alive
93 : * and in a park position. kthread_unpark() "restarts" the thread and
94 : * calls the thread function again.
95 : */
96 180218 : bool kthread_should_park(void)
97 : {
98 360436 : return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(current)->flags);
99 : }
100 :
101 : /**
102 : * kthread_freezable_should_stop - should this freezable kthread return now?
103 : * @was_frozen: optional out parameter, indicates whether %current was frozen
104 : *
105 : * kthread_should_stop() for freezable kthreads, which will enter
106 : * refrigerator if necessary. This function is safe from kthread_stop() /
107 : * freezer deadlock and freezable kthreads should use this function instead
108 : * of calling try_to_freeze() directly.
109 : */
110 0 : bool kthread_freezable_should_stop(bool *was_frozen)
111 : {
112 : bool frozen = false;
113 :
114 : might_sleep();
115 :
116 0 : if (unlikely(freezing(current)))
117 0 : frozen = __refrigerator(true);
118 :
119 0 : if (was_frozen)
120 0 : *was_frozen = frozen;
121 :
122 0 : return kthread_should_stop();
123 : }
124 : EXPORT_SYMBOL_GPL(kthread_freezable_should_stop);
125 :
126 : /**
127 : * kthread_data - return data value specified on kthread creation
128 : * @task: kthread task in question
129 : *
130 : * Return the data value specified when kthread @task was created.
131 : * The caller is responsible for ensuring the validity of @task when
132 : * calling this function.
133 : */
134 85434 : void *kthread_data(struct task_struct *task)
135 : {
136 85434 : return to_kthread(task)->data;
137 : }
138 :
139 : /**
140 : * probe_kthread_data - speculative version of kthread_data()
141 : * @task: possible kthread task in question
142 : *
143 : * @task could be a kthread task. Return the data value specified when it
144 : * was created if accessible. If @task isn't a kthread task or its data is
145 : * inaccessible for any reason, %NULL is returned. This function requires
146 : * that @task itself is safe to dereference.
147 : */
148 0 : void *probe_kthread_data(struct task_struct *task)
149 : {
150 : struct kthread *kthread = to_kthread(task);
151 0 : void *data = NULL;
152 :
153 0 : probe_kernel_read(&data, &kthread->data, sizeof(data));
154 0 : return data;
155 : }
156 :
157 46 : static void __kthread_parkme(struct kthread *self)
158 : {
159 46 : __set_current_state(TASK_PARKED);
160 93 : while (test_bit(KTHREAD_SHOULD_PARK, &self->flags)) {
161 1 : if (!test_and_set_bit(KTHREAD_IS_PARKED, &self->flags))
162 1 : complete(&self->parked);
163 1 : schedule();
164 1 : __set_current_state(TASK_PARKED);
165 : }
166 : clear_bit(KTHREAD_IS_PARKED, &self->flags);
167 46 : __set_current_state(TASK_RUNNING);
168 46 : }
169 :
170 0 : void kthread_parkme(void)
171 : {
172 0 : __kthread_parkme(to_kthread(current));
173 0 : }
174 :
175 46 : static int kthread(void *_create)
176 : {
177 : /* Copy data: it's on kthread's stack */
178 : struct kthread_create_info *create = _create;
179 46 : int (*threadfn)(void *data) = create->threadfn;
180 46 : void *data = create->data;
181 : struct completion *done;
182 : struct kthread self;
183 : int ret;
184 :
185 46 : self.flags = 0;
186 46 : self.data = data;
187 : init_completion(&self.exited);
188 : init_completion(&self.parked);
189 46 : current->vfork_done = &self.exited;
190 :
191 : /* If user was SIGKILLed, I release the structure. */
192 92 : done = xchg(&create->done, NULL);
193 46 : if (!done) {
194 0 : kfree(create);
195 0 : do_exit(-EINTR);
196 : }
197 : /* OK, tell user we're spawned, wait for stop or wakeup */
198 46 : __set_current_state(TASK_UNINTERRUPTIBLE);
199 46 : create->result = current;
200 46 : complete(done);
201 46 : schedule();
202 :
203 : ret = -EINTR;
204 :
205 46 : if (!test_bit(KTHREAD_SHOULD_STOP, &self.flags)) {
206 46 : __kthread_parkme(&self);
207 46 : ret = threadfn(data);
208 : }
209 : /* we can't just return, we must preserve "self" on stack */
210 6 : do_exit(ret);
211 : }
212 :
213 : /* called from do_fork() to get node information for about to be created task */
214 2993 : int tsk_fork_get_node(struct task_struct *tsk)
215 : {
216 : #ifdef CONFIG_NUMA
217 : if (tsk == kthreadd_task)
218 : return tsk->pref_node_fork;
219 : #endif
220 2993 : return NUMA_NO_NODE;
221 : }
222 :
223 46 : static void create_kthread(struct kthread_create_info *create)
224 : {
225 : int pid;
226 :
227 : #ifdef CONFIG_NUMA
228 : current->pref_node_fork = create->node;
229 : #endif
230 : /* We want our own signal handler (we take no signals by default). */
231 46 : pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD);
232 46 : if (pid < 0) {
233 : /* If user was SIGKILLed, I release the structure. */
234 0 : struct completion *done = xchg(&create->done, NULL);
235 :
236 0 : if (!done) {
237 0 : kfree(create);
238 46 : return;
239 : }
240 0 : create->result = ERR_PTR(pid);
241 0 : complete(done);
242 : }
243 : }
244 :
245 : /**
246 : * kthread_create_on_node - create a kthread.
247 : * @threadfn: the function to run until signal_pending(current).
248 : * @data: data ptr for @threadfn.
249 : * @node: memory node number.
250 : * @namefmt: printf-style name for the thread.
251 : *
252 : * Description: This helper function creates and names a kernel
253 : * thread. The thread will be stopped: use wake_up_process() to start
254 : * it. See also kthread_run().
255 : *
256 : * If thread is going to be bound on a particular cpu, give its node
257 : * in @node, to get NUMA affinity for kthread stack, or else give -1.
258 : * When woken, the thread will run @threadfn() with @data as its
259 : * argument. @threadfn() can either call do_exit() directly if it is a
260 : * standalone thread for which no one will call kthread_stop(), or
261 : * return when 'kthread_should_stop()' is true (which means
262 : * kthread_stop() has been called). The return value should be zero
263 : * or a negative error number; it will be passed to kthread_stop().
264 : *
265 : * Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR).
266 : */
267 46 : struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
268 : void *data, int node,
269 : const char namefmt[],
270 : ...)
271 : {
272 46 : DECLARE_COMPLETION_ONSTACK(done);
273 : struct task_struct *task;
274 : struct kthread_create_info *create = kmalloc(sizeof(*create),
275 : GFP_KERNEL);
276 :
277 46 : if (!create)
278 : return ERR_PTR(-ENOMEM);
279 46 : create->threadfn = threadfn;
280 46 : create->data = data;
281 46 : create->node = node;
282 46 : create->done = &done;
283 :
284 : spin_lock(&kthread_create_lock);
285 46 : list_add_tail(&create->list, &kthread_create_list);
286 : spin_unlock(&kthread_create_lock);
287 :
288 46 : wake_up_process(kthreadd_task);
289 : /*
290 : * Wait for completion in killable state, for I might be chosen by
291 : * the OOM killer while kthreadd is trying to allocate memory for
292 : * new kernel thread.
293 : */
294 46 : if (unlikely(wait_for_completion_killable(&done))) {
295 : /*
296 : * If I was SIGKILLed before kthreadd (or new kernel thread)
297 : * calls complete(), leave the cleanup of this structure to
298 : * that thread.
299 : */
300 0 : if (xchg(&create->done, NULL))
301 : return ERR_PTR(-EINTR);
302 : /*
303 : * kthreadd (or new kernel thread) will call complete()
304 : * shortly.
305 : */
306 0 : wait_for_completion(&done);
307 : }
308 46 : task = create->result;
309 46 : if (!IS_ERR(task)) {
310 : static const struct sched_param param = { .sched_priority = 0 };
311 : va_list args;
312 :
313 46 : va_start(args, namefmt);
314 46 : vsnprintf(task->comm, sizeof(task->comm), namefmt, args);
315 46 : va_end(args);
316 : /*
317 : * root may have changed our (kthreadd's) priority or CPU mask.
318 : * The kernel thread should not inherit these properties.
319 : */
320 46 : sched_setscheduler_nocheck(task, SCHED_NORMAL, ¶m);
321 : set_cpus_allowed_ptr(task, cpu_all_mask);
322 : }
323 46 : kfree(create);
324 46 : return task;
325 : }
326 : EXPORT_SYMBOL(kthread_create_on_node);
327 :
328 : static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state)
329 : {
330 : /* Must have done schedule() in kthread() before we set_task_cpu */
331 : if (!wait_task_inactive(p, state)) {
332 : WARN_ON(1);
333 : return;
334 : }
335 : /* It's safe because the task is inactive. */
336 : do_set_cpus_allowed(p, cpumask_of(cpu));
337 1 : p->flags |= PF_NO_SETAFFINITY;
338 : }
339 :
340 : /**
341 : * kthread_bind - bind a just-created kthread to a cpu.
342 : * @p: thread created by kthread_create().
343 : * @cpu: cpu (might not be online, must be possible) for @k to run on.
344 : *
345 : * Description: This function is equivalent to set_cpus_allowed(),
346 : * except that @cpu doesn't need to be online, and the thread must be
347 : * stopped (i.e., just returned from kthread_create()).
348 : */
349 0 : void kthread_bind(struct task_struct *p, unsigned int cpu)
350 : {
351 : __kthread_bind(p, cpu, TASK_UNINTERRUPTIBLE);
352 0 : }
353 : EXPORT_SYMBOL(kthread_bind);
354 :
355 : /**
356 : * kthread_create_on_cpu - Create a cpu bound kthread
357 : * @threadfn: the function to run until signal_pending(current).
358 : * @data: data ptr for @threadfn.
359 : * @cpu: The cpu on which the thread should be bound,
360 : * @namefmt: printf-style name for the thread. Format is restricted
361 : * to "name.*%u". Code fills in cpu number.
362 : *
363 : * Description: This helper function creates and names a kernel thread
364 : * The thread will be woken and put into park mode.
365 : */
366 1 : struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
367 : void *data, unsigned int cpu,
368 : const char *namefmt)
369 : {
370 : struct task_struct *p;
371 :
372 1 : p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt,
373 : cpu);
374 1 : if (IS_ERR(p))
375 : return p;
376 : set_bit(KTHREAD_IS_PER_CPU, &to_kthread(p)->flags);
377 1 : to_kthread(p)->cpu = cpu;
378 : /* Park the thread to get it out of TASK_UNINTERRUPTIBLE state */
379 1 : kthread_park(p);
380 1 : return p;
381 : }
382 :
383 1 : static void __kthread_unpark(struct task_struct *k, struct kthread *kthread)
384 : {
385 : clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
386 : /*
387 : * We clear the IS_PARKED bit here as we don't wait
388 : * until the task has left the park code. So if we'd
389 : * park before that happens we'd see the IS_PARKED bit
390 : * which might be about to be cleared.
391 : */
392 1 : if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) {
393 1 : if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
394 : __kthread_bind(k, kthread->cpu, TASK_PARKED);
395 1 : wake_up_state(k, TASK_PARKED);
396 : }
397 1 : }
398 :
399 : /**
400 : * kthread_unpark - unpark a thread created by kthread_create().
401 : * @k: thread created by kthread_create().
402 : *
403 : * Sets kthread_should_park() for @k to return false, wakes it, and
404 : * waits for it to return. If the thread is marked percpu then its
405 : * bound to the cpu again.
406 : */
407 1 : void kthread_unpark(struct task_struct *k)
408 : {
409 : struct kthread *kthread = to_live_kthread(k);
410 :
411 1 : if (kthread)
412 1 : __kthread_unpark(k, kthread);
413 1 : }
414 :
415 : /**
416 : * kthread_park - park a thread created by kthread_create().
417 : * @k: thread created by kthread_create().
418 : *
419 : * Sets kthread_should_park() for @k to return true, wakes it, and
420 : * waits for it to return. This can also be called after kthread_create()
421 : * instead of calling wake_up_process(): the thread will park without
422 : * calling threadfn().
423 : *
424 : * Returns 0 if the thread is parked, -ENOSYS if the thread exited.
425 : * If called by the kthread itself just the park bit is set.
426 : */
427 1 : int kthread_park(struct task_struct *k)
428 : {
429 : struct kthread *kthread = to_live_kthread(k);
430 : int ret = -ENOSYS;
431 :
432 1 : if (kthread) {
433 1 : if (!test_bit(KTHREAD_IS_PARKED, &kthread->flags)) {
434 : set_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
435 1 : if (k != current) {
436 1 : wake_up_process(k);
437 1 : wait_for_completion(&kthread->parked);
438 : }
439 : }
440 : ret = 0;
441 : }
442 1 : return ret;
443 : }
444 :
445 : /**
446 : * kthread_stop - stop a thread created by kthread_create().
447 : * @k: thread created by kthread_create().
448 : *
449 : * Sets kthread_should_stop() for @k to return true, wakes it, and
450 : * waits for it to exit. This can also be called after kthread_create()
451 : * instead of calling wake_up_process(): the thread will exit without
452 : * calling threadfn().
453 : *
454 : * If threadfn() may call do_exit() itself, the caller must ensure
455 : * task_struct can't go away.
456 : *
457 : * Returns the result of threadfn(), or %-EINTR if wake_up_process()
458 : * was never called.
459 : */
460 0 : int kthread_stop(struct task_struct *k)
461 : {
462 : struct kthread *kthread;
463 : int ret;
464 :
465 : trace_sched_kthread_stop(k);
466 :
467 0 : get_task_struct(k);
468 : kthread = to_live_kthread(k);
469 0 : if (kthread) {
470 : set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
471 0 : __kthread_unpark(k, kthread);
472 0 : wake_up_process(k);
473 0 : wait_for_completion(&kthread->exited);
474 : }
475 0 : ret = k->exit_code;
476 : put_task_struct(k);
477 :
478 : trace_sched_kthread_stop_ret(ret);
479 0 : return ret;
480 : }
481 : EXPORT_SYMBOL(kthread_stop);
482 :
483 1 : int kthreadd(void *unused)
484 : {
485 1 : struct task_struct *tsk = current;
486 :
487 : /* Setup a clean context for our children to inherit. */
488 : set_task_comm(tsk, "kthreadd");
489 1 : ignore_signals(tsk);
490 : set_cpus_allowed_ptr(tsk, cpu_all_mask);
491 : set_mems_allowed(node_states[N_MEMORY]);
492 :
493 1 : current->flags |= PF_NOFREEZE;
494 :
495 : for (;;) {
496 47 : set_current_state(TASK_INTERRUPTIBLE);
497 47 : if (list_empty(&kthread_create_list))
498 47 : schedule();
499 46 : __set_current_state(TASK_RUNNING);
500 :
501 : spin_lock(&kthread_create_lock);
502 92 : while (!list_empty(&kthread_create_list)) {
503 : struct kthread_create_info *create;
504 :
505 46 : create = list_entry(kthread_create_list.next,
506 : struct kthread_create_info, list);
507 46 : list_del_init(&create->list);
508 : spin_unlock(&kthread_create_lock);
509 :
510 46 : create_kthread(create);
511 :
512 : spin_lock(&kthread_create_lock);
513 : }
514 : spin_unlock(&kthread_create_lock);
515 : }
516 :
517 : return 0;
518 : }
519 :
520 0 : void __init_kthread_worker(struct kthread_worker *worker,
521 : const char *name,
522 : struct lock_class_key *key)
523 : {
524 : spin_lock_init(&worker->lock);
525 : lockdep_set_class_and_name(&worker->lock, key, name);
526 0 : INIT_LIST_HEAD(&worker->work_list);
527 0 : worker->task = NULL;
528 0 : }
529 : EXPORT_SYMBOL_GPL(__init_kthread_worker);
530 :
531 : /**
532 : * kthread_worker_fn - kthread function to process kthread_worker
533 : * @worker_ptr: pointer to initialized kthread_worker
534 : *
535 : * This function can be used as @threadfn to kthread_create() or
536 : * kthread_run() with @worker_ptr argument pointing to an initialized
537 : * kthread_worker. The started kthread will process work_list until
538 : * the it is stopped with kthread_stop(). A kthread can also call
539 : * this function directly after extra initialization.
540 : *
541 : * Different kthreads can be used for the same kthread_worker as long
542 : * as there's only one kthread attached to it at any given time. A
543 : * kthread_worker without an attached kthread simply collects queued
544 : * kthread_works.
545 : */
546 0 : int kthread_worker_fn(void *worker_ptr)
547 : {
548 : struct kthread_worker *worker = worker_ptr;
549 : struct kthread_work *work;
550 :
551 : WARN_ON(worker->task);
552 0 : worker->task = current;
553 : repeat:
554 0 : set_current_state(TASK_INTERRUPTIBLE); /* mb paired w/ kthread_stop */
555 :
556 0 : if (kthread_should_stop()) {
557 0 : __set_current_state(TASK_RUNNING);
558 : spin_lock_irq(&worker->lock);
559 0 : worker->task = NULL;
560 : spin_unlock_irq(&worker->lock);
561 0 : return 0;
562 : }
563 :
564 : work = NULL;
565 : spin_lock_irq(&worker->lock);
566 0 : if (!list_empty(&worker->work_list)) {
567 : work = list_first_entry(&worker->work_list,
568 : struct kthread_work, node);
569 0 : list_del_init(&work->node);
570 : }
571 0 : worker->current_work = work;
572 : spin_unlock_irq(&worker->lock);
573 :
574 0 : if (work) {
575 0 : __set_current_state(TASK_RUNNING);
576 0 : work->func(work);
577 0 : } else if (!freezing(current))
578 0 : schedule();
579 :
580 : try_to_freeze();
581 : goto repeat;
582 : }
583 : EXPORT_SYMBOL_GPL(kthread_worker_fn);
584 :
585 : /* insert @work before @pos in @worker */
586 0 : static void insert_kthread_work(struct kthread_worker *worker,
587 : struct kthread_work *work,
588 : struct list_head *pos)
589 : {
590 : lockdep_assert_held(&worker->lock);
591 :
592 0 : list_add_tail(&work->node, pos);
593 0 : work->worker = worker;
594 0 : if (!worker->current_work && likely(worker->task))
595 0 : wake_up_process(worker->task);
596 0 : }
597 :
598 : /**
599 : * queue_kthread_work - queue a kthread_work
600 : * @worker: target kthread_worker
601 : * @work: kthread_work to queue
602 : *
603 : * Queue @work to work processor @task for async execution. @task
604 : * must have been created with kthread_worker_create(). Returns %true
605 : * if @work was successfully queued, %false if it was already pending.
606 : */
607 0 : bool queue_kthread_work(struct kthread_worker *worker,
608 : struct kthread_work *work)
609 : {
610 : bool ret = false;
611 : unsigned long flags;
612 :
613 0 : spin_lock_irqsave(&worker->lock, flags);
614 0 : if (list_empty(&work->node)) {
615 0 : insert_kthread_work(worker, work, &worker->work_list);
616 : ret = true;
617 : }
618 : spin_unlock_irqrestore(&worker->lock, flags);
619 0 : return ret;
620 : }
621 : EXPORT_SYMBOL_GPL(queue_kthread_work);
622 :
623 : struct kthread_flush_work {
624 : struct kthread_work work;
625 : struct completion done;
626 : };
627 :
628 0 : static void kthread_flush_work_fn(struct kthread_work *work)
629 : {
630 : struct kthread_flush_work *fwork =
631 : container_of(work, struct kthread_flush_work, work);
632 0 : complete(&fwork->done);
633 0 : }
634 :
635 : /**
636 : * flush_kthread_work - flush a kthread_work
637 : * @work: work to flush
638 : *
639 : * If @work is queued or executing, wait for it to finish execution.
640 : */
641 0 : void flush_kthread_work(struct kthread_work *work)
642 : {
643 0 : struct kthread_flush_work fwork = {
644 : KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
645 0 : COMPLETION_INITIALIZER_ONSTACK(fwork.done),
646 : };
647 : struct kthread_worker *worker;
648 : bool noop = false;
649 :
650 : retry:
651 0 : worker = work->worker;
652 0 : if (!worker)
653 0 : return;
654 :
655 : spin_lock_irq(&worker->lock);
656 0 : if (work->worker != worker) {
657 : spin_unlock_irq(&worker->lock);
658 : goto retry;
659 : }
660 :
661 0 : if (!list_empty(&work->node))
662 0 : insert_kthread_work(worker, &fwork.work, work->node.next);
663 0 : else if (worker->current_work == work)
664 0 : insert_kthread_work(worker, &fwork.work, worker->work_list.next);
665 : else
666 : noop = true;
667 :
668 : spin_unlock_irq(&worker->lock);
669 :
670 0 : if (!noop)
671 0 : wait_for_completion(&fwork.done);
672 : }
673 : EXPORT_SYMBOL_GPL(flush_kthread_work);
674 :
675 : /**
676 : * flush_kthread_worker - flush all current works on a kthread_worker
677 : * @worker: worker to flush
678 : *
679 : * Wait until all currently executing or pending works on @worker are
680 : * finished.
681 : */
682 0 : void flush_kthread_worker(struct kthread_worker *worker)
683 : {
684 0 : struct kthread_flush_work fwork = {
685 : KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn),
686 0 : COMPLETION_INITIALIZER_ONSTACK(fwork.done),
687 : };
688 :
689 0 : queue_kthread_work(worker, &fwork.work);
690 0 : wait_for_completion(&fwork.done);
691 0 : }
692 : EXPORT_SYMBOL_GPL(flush_kthread_worker);
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