Commit | Line | Data |
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1da177e4 LT |
1 | /* Kernel thread helper functions. |
2 | * Copyright (C) 2004 IBM Corporation, Rusty Russell. | |
3 | * | |
73c27992 | 4 | * Creation is done via kthreadd, so that we get a clean environment |
1da177e4 LT |
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> | |
58568d2a | 12 | #include <linux/cpuset.h> |
1da177e4 LT |
13 | #include <linux/unistd.h> |
14 | #include <linux/file.h> | |
9984de1a | 15 | #include <linux/export.h> |
97d1f15b | 16 | #include <linux/mutex.h> |
b56c0d89 TH |
17 | #include <linux/slab.h> |
18 | #include <linux/freezer.h> | |
a74fb73c | 19 | #include <linux/ptrace.h> |
cd42d559 | 20 | #include <linux/uaccess.h> |
ad8d75ff | 21 | #include <trace/events/sched.h> |
1da177e4 | 22 | |
73c27992 EB |
23 | static DEFINE_SPINLOCK(kthread_create_lock); |
24 | static LIST_HEAD(kthread_create_list); | |
25 | struct task_struct *kthreadd_task; | |
1da177e4 LT |
26 | |
27 | struct kthread_create_info | |
28 | { | |
73c27992 | 29 | /* Information passed to kthread() from kthreadd. */ |
1da177e4 LT |
30 | int (*threadfn)(void *data); |
31 | void *data; | |
207205a2 | 32 | int node; |
1da177e4 | 33 | |
73c27992 | 34 | /* Result passed back to kthread_create() from kthreadd. */ |
1da177e4 | 35 | struct task_struct *result; |
786235ee | 36 | struct completion *done; |
65f27f38 | 37 | |
73c27992 | 38 | struct list_head list; |
1da177e4 LT |
39 | }; |
40 | ||
63706172 | 41 | struct kthread { |
2a1d4460 TG |
42 | unsigned long flags; |
43 | unsigned int cpu; | |
82805ab7 | 44 | void *data; |
2a1d4460 | 45 | struct completion parked; |
63706172 | 46 | struct completion exited; |
1da177e4 LT |
47 | }; |
48 | ||
2a1d4460 TG |
49 | enum KTHREAD_BITS { |
50 | KTHREAD_IS_PER_CPU = 0, | |
51 | KTHREAD_SHOULD_STOP, | |
52 | KTHREAD_SHOULD_PARK, | |
53 | KTHREAD_IS_PARKED, | |
54 | }; | |
55 | ||
4ecdafc8 ON |
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 | return __to_kthread(k->vfork_done); | |
62 | } | |
63 | ||
64 | static struct kthread *to_live_kthread(struct task_struct *k) | |
65 | { | |
66 | struct completion *vfork = ACCESS_ONCE(k->vfork_done); | |
67 | if (likely(vfork)) | |
68 | return __to_kthread(vfork); | |
69 | return NULL; | |
70 | } | |
1da177e4 | 71 | |
9e37bd30 RD |
72 | /** |
73 | * kthread_should_stop - should this kthread return now? | |
74 | * | |
72fd4a35 | 75 | * When someone calls kthread_stop() on your kthread, it will be woken |
9e37bd30 RD |
76 | * and this will return true. You should then return, and your return |
77 | * value will be passed through to kthread_stop(). | |
78 | */ | |
2a1d4460 | 79 | bool kthread_should_stop(void) |
1da177e4 | 80 | { |
2a1d4460 | 81 | return test_bit(KTHREAD_SHOULD_STOP, &to_kthread(current)->flags); |
1da177e4 LT |
82 | } |
83 | EXPORT_SYMBOL(kthread_should_stop); | |
84 | ||
2a1d4460 TG |
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 | bool kthread_should_park(void) | |
97 | { | |
98 | return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(current)->flags); | |
99 | } | |
18896451 | 100 | EXPORT_SYMBOL_GPL(kthread_should_park); |
2a1d4460 | 101 | |
8a32c441 TH |
102 | /** |
103 | * kthread_freezable_should_stop - should this freezable kthread return now? | |
104 | * @was_frozen: optional out parameter, indicates whether %current was frozen | |
105 | * | |
106 | * kthread_should_stop() for freezable kthreads, which will enter | |
107 | * refrigerator if necessary. This function is safe from kthread_stop() / | |
108 | * freezer deadlock and freezable kthreads should use this function instead | |
109 | * of calling try_to_freeze() directly. | |
110 | */ | |
111 | bool kthread_freezable_should_stop(bool *was_frozen) | |
112 | { | |
113 | bool frozen = false; | |
114 | ||
115 | might_sleep(); | |
116 | ||
117 | if (unlikely(freezing(current))) | |
118 | frozen = __refrigerator(true); | |
119 | ||
120 | if (was_frozen) | |
121 | *was_frozen = frozen; | |
122 | ||
123 | return kthread_should_stop(); | |
124 | } | |
125 | EXPORT_SYMBOL_GPL(kthread_freezable_should_stop); | |
126 | ||
82805ab7 TH |
127 | /** |
128 | * kthread_data - return data value specified on kthread creation | |
129 | * @task: kthread task in question | |
130 | * | |
131 | * Return the data value specified when kthread @task was created. | |
132 | * The caller is responsible for ensuring the validity of @task when | |
133 | * calling this function. | |
134 | */ | |
135 | void *kthread_data(struct task_struct *task) | |
136 | { | |
137 | return to_kthread(task)->data; | |
138 | } | |
139 | ||
cd42d559 | 140 | /** |
fcc12192 | 141 | * kthread_probe_data - speculative version of kthread_data() |
cd42d559 TH |
142 | * @task: possible kthread task in question |
143 | * | |
144 | * @task could be a kthread task. Return the data value specified when it | |
145 | * was created if accessible. If @task isn't a kthread task or its data is | |
146 | * inaccessible for any reason, %NULL is returned. This function requires | |
147 | * that @task itself is safe to dereference. | |
148 | */ | |
fcc12192 | 149 | void *kthread_probe_data(struct task_struct *task) |
cd42d559 TH |
150 | { |
151 | struct kthread *kthread = to_kthread(task); | |
152 | void *data = NULL; | |
153 | ||
154 | probe_kernel_read(&data, &kthread->data, sizeof(data)); | |
155 | return data; | |
156 | } | |
157 | ||
2a1d4460 TG |
158 | static void __kthread_parkme(struct kthread *self) |
159 | { | |
f2530dc7 | 160 | __set_current_state(TASK_PARKED); |
2a1d4460 TG |
161 | while (test_bit(KTHREAD_SHOULD_PARK, &self->flags)) { |
162 | if (!test_and_set_bit(KTHREAD_IS_PARKED, &self->flags)) | |
163 | complete(&self->parked); | |
164 | schedule(); | |
f2530dc7 | 165 | __set_current_state(TASK_PARKED); |
2a1d4460 TG |
166 | } |
167 | clear_bit(KTHREAD_IS_PARKED, &self->flags); | |
168 | __set_current_state(TASK_RUNNING); | |
169 | } | |
170 | ||
171 | void kthread_parkme(void) | |
172 | { | |
173 | __kthread_parkme(to_kthread(current)); | |
174 | } | |
18896451 | 175 | EXPORT_SYMBOL_GPL(kthread_parkme); |
2a1d4460 | 176 | |
1da177e4 LT |
177 | static int kthread(void *_create) |
178 | { | |
63706172 | 179 | /* Copy data: it's on kthread's stack */ |
1da177e4 | 180 | struct kthread_create_info *create = _create; |
63706172 ON |
181 | int (*threadfn)(void *data) = create->threadfn; |
182 | void *data = create->data; | |
786235ee | 183 | struct completion *done; |
63706172 ON |
184 | struct kthread self; |
185 | int ret; | |
1da177e4 | 186 | |
2a1d4460 | 187 | self.flags = 0; |
82805ab7 | 188 | self.data = data; |
63706172 | 189 | init_completion(&self.exited); |
2a1d4460 | 190 | init_completion(&self.parked); |
63706172 | 191 | current->vfork_done = &self.exited; |
1da177e4 | 192 | |
786235ee TH |
193 | /* If user was SIGKILLed, I release the structure. */ |
194 | done = xchg(&create->done, NULL); | |
195 | if (!done) { | |
196 | kfree(create); | |
197 | do_exit(-EINTR); | |
198 | } | |
1da177e4 | 199 | /* OK, tell user we're spawned, wait for stop or wakeup */ |
a076e4bc | 200 | __set_current_state(TASK_UNINTERRUPTIBLE); |
3217ab97 | 201 | create->result = current; |
786235ee | 202 | complete(done); |
1da177e4 LT |
203 | schedule(); |
204 | ||
63706172 | 205 | ret = -EINTR; |
1da177e4 | 206 | |
2a1d4460 TG |
207 | if (!test_bit(KTHREAD_SHOULD_STOP, &self.flags)) { |
208 | __kthread_parkme(&self); | |
209 | ret = threadfn(data); | |
210 | } | |
63706172 ON |
211 | /* we can't just return, we must preserve "self" on stack */ |
212 | do_exit(ret); | |
1da177e4 LT |
213 | } |
214 | ||
207205a2 ED |
215 | /* called from do_fork() to get node information for about to be created task */ |
216 | int tsk_fork_get_node(struct task_struct *tsk) | |
217 | { | |
218 | #ifdef CONFIG_NUMA | |
219 | if (tsk == kthreadd_task) | |
220 | return tsk->pref_node_fork; | |
221 | #endif | |
81c98869 | 222 | return NUMA_NO_NODE; |
207205a2 ED |
223 | } |
224 | ||
73c27992 | 225 | static void create_kthread(struct kthread_create_info *create) |
1da177e4 | 226 | { |
1da177e4 LT |
227 | int pid; |
228 | ||
207205a2 ED |
229 | #ifdef CONFIG_NUMA |
230 | current->pref_node_fork = create->node; | |
231 | #endif | |
1da177e4 LT |
232 | /* We want our own signal handler (we take no signals by default). */ |
233 | pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD); | |
cdd140bd | 234 | if (pid < 0) { |
786235ee TH |
235 | /* If user was SIGKILLed, I release the structure. */ |
236 | struct completion *done = xchg(&create->done, NULL); | |
237 | ||
238 | if (!done) { | |
239 | kfree(create); | |
240 | return; | |
241 | } | |
1da177e4 | 242 | create->result = ERR_PTR(pid); |
786235ee | 243 | complete(done); |
cdd140bd | 244 | } |
1da177e4 LT |
245 | } |
246 | ||
1ceae44b PM |
247 | static struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data), |
248 | void *data, int node, | |
249 | const char namefmt[], | |
250 | va_list args) | |
1da177e4 | 251 | { |
786235ee TH |
252 | DECLARE_COMPLETION_ONSTACK(done); |
253 | struct task_struct *task; | |
254 | struct kthread_create_info *create = kmalloc(sizeof(*create), | |
255 | GFP_KERNEL); | |
256 | ||
257 | if (!create) | |
258 | return ERR_PTR(-ENOMEM); | |
259 | create->threadfn = threadfn; | |
260 | create->data = data; | |
261 | create->node = node; | |
262 | create->done = &done; | |
73c27992 EB |
263 | |
264 | spin_lock(&kthread_create_lock); | |
786235ee | 265 | list_add_tail(&create->list, &kthread_create_list); |
73c27992 EB |
266 | spin_unlock(&kthread_create_lock); |
267 | ||
cbd9b67b | 268 | wake_up_process(kthreadd_task); |
786235ee TH |
269 | /* |
270 | * Wait for completion in killable state, for I might be chosen by | |
271 | * the OOM killer while kthreadd is trying to allocate memory for | |
272 | * new kernel thread. | |
273 | */ | |
274 | if (unlikely(wait_for_completion_killable(&done))) { | |
275 | /* | |
276 | * If I was SIGKILLed before kthreadd (or new kernel thread) | |
277 | * calls complete(), leave the cleanup of this structure to | |
278 | * that thread. | |
279 | */ | |
280 | if (xchg(&create->done, NULL)) | |
8fe6929c | 281 | return ERR_PTR(-EINTR); |
786235ee TH |
282 | /* |
283 | * kthreadd (or new kernel thread) will call complete() | |
284 | * shortly. | |
285 | */ | |
286 | wait_for_completion(&done); | |
287 | } | |
288 | task = create->result; | |
289 | if (!IS_ERR(task)) { | |
c9b5f501 | 290 | static const struct sched_param param = { .sched_priority = 0 }; |
1c99315b | 291 | |
786235ee | 292 | vsnprintf(task->comm, sizeof(task->comm), namefmt, args); |
1c99315b ON |
293 | /* |
294 | * root may have changed our (kthreadd's) priority or CPU mask. | |
295 | * The kernel thread should not inherit these properties. | |
296 | */ | |
786235ee TH |
297 | sched_setscheduler_nocheck(task, SCHED_NORMAL, ¶m); |
298 | set_cpus_allowed_ptr(task, cpu_all_mask); | |
1da177e4 | 299 | } |
786235ee TH |
300 | kfree(create); |
301 | return task; | |
1da177e4 | 302 | } |
1ceae44b PM |
303 | |
304 | /** | |
305 | * kthread_create_on_node - create a kthread. | |
306 | * @threadfn: the function to run until signal_pending(current). | |
307 | * @data: data ptr for @threadfn. | |
308 | * @node: task and thread structures for the thread are allocated on this node | |
309 | * @namefmt: printf-style name for the thread. | |
310 | * | |
311 | * Description: This helper function creates and names a kernel | |
312 | * thread. The thread will be stopped: use wake_up_process() to start | |
313 | * it. See also kthread_run(). The new thread has SCHED_NORMAL policy and | |
314 | * is affine to all CPUs. | |
315 | * | |
316 | * If thread is going to be bound on a particular cpu, give its node | |
317 | * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE. | |
318 | * When woken, the thread will run @threadfn() with @data as its | |
319 | * argument. @threadfn() can either call do_exit() directly if it is a | |
320 | * standalone thread for which no one will call kthread_stop(), or | |
321 | * return when 'kthread_should_stop()' is true (which means | |
322 | * kthread_stop() has been called). The return value should be zero | |
323 | * or a negative error number; it will be passed to kthread_stop(). | |
324 | * | |
325 | * Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR). | |
326 | */ | |
327 | struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), | |
328 | void *data, int node, | |
329 | const char namefmt[], | |
330 | ...) | |
331 | { | |
332 | struct task_struct *task; | |
333 | va_list args; | |
334 | ||
335 | va_start(args, namefmt); | |
336 | task = __kthread_create_on_node(threadfn, data, node, namefmt, args); | |
337 | va_end(args); | |
338 | ||
339 | return task; | |
340 | } | |
207205a2 | 341 | EXPORT_SYMBOL(kthread_create_on_node); |
1da177e4 | 342 | |
25834c73 | 343 | static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, long state) |
2a1d4460 | 344 | { |
25834c73 PZ |
345 | unsigned long flags; |
346 | ||
f2530dc7 TG |
347 | if (!wait_task_inactive(p, state)) { |
348 | WARN_ON(1); | |
349 | return; | |
350 | } | |
25834c73 | 351 | |
2a1d4460 | 352 | /* It's safe because the task is inactive. */ |
25834c73 PZ |
353 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
354 | do_set_cpus_allowed(p, mask); | |
14a40ffc | 355 | p->flags |= PF_NO_SETAFFINITY; |
25834c73 PZ |
356 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
357 | } | |
358 | ||
359 | static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state) | |
360 | { | |
361 | __kthread_bind_mask(p, cpumask_of(cpu), state); | |
362 | } | |
363 | ||
364 | void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask) | |
365 | { | |
366 | __kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE); | |
2a1d4460 TG |
367 | } |
368 | ||
881232b7 PZ |
369 | /** |
370 | * kthread_bind - bind a just-created kthread to a cpu. | |
371 | * @p: thread created by kthread_create(). | |
372 | * @cpu: cpu (might not be online, must be possible) for @k to run on. | |
373 | * | |
374 | * Description: This function is equivalent to set_cpus_allowed(), | |
375 | * except that @cpu doesn't need to be online, and the thread must be | |
376 | * stopped (i.e., just returned from kthread_create()). | |
377 | */ | |
378 | void kthread_bind(struct task_struct *p, unsigned int cpu) | |
379 | { | |
f2530dc7 | 380 | __kthread_bind(p, cpu, TASK_UNINTERRUPTIBLE); |
881232b7 PZ |
381 | } |
382 | EXPORT_SYMBOL(kthread_bind); | |
383 | ||
2a1d4460 TG |
384 | /** |
385 | * kthread_create_on_cpu - Create a cpu bound kthread | |
386 | * @threadfn: the function to run until signal_pending(current). | |
387 | * @data: data ptr for @threadfn. | |
388 | * @cpu: The cpu on which the thread should be bound, | |
389 | * @namefmt: printf-style name for the thread. Format is restricted | |
390 | * to "name.*%u". Code fills in cpu number. | |
391 | * | |
392 | * Description: This helper function creates and names a kernel thread | |
393 | * The thread will be woken and put into park mode. | |
394 | */ | |
395 | struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), | |
396 | void *data, unsigned int cpu, | |
397 | const char *namefmt) | |
398 | { | |
399 | struct task_struct *p; | |
400 | ||
10922838 | 401 | p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt, |
2a1d4460 TG |
402 | cpu); |
403 | if (IS_ERR(p)) | |
404 | return p; | |
e7616668 PM |
405 | kthread_bind(p, cpu); |
406 | /* CPU hotplug need to bind once again when unparking the thread. */ | |
2a1d4460 TG |
407 | set_bit(KTHREAD_IS_PER_CPU, &to_kthread(p)->flags); |
408 | to_kthread(p)->cpu = cpu; | |
2a1d4460 TG |
409 | return p; |
410 | } | |
411 | ||
f2530dc7 TG |
412 | static void __kthread_unpark(struct task_struct *k, struct kthread *kthread) |
413 | { | |
414 | clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags); | |
415 | /* | |
416 | * We clear the IS_PARKED bit here as we don't wait | |
417 | * until the task has left the park code. So if we'd | |
418 | * park before that happens we'd see the IS_PARKED bit | |
419 | * which might be about to be cleared. | |
420 | */ | |
421 | if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) { | |
e7616668 PM |
422 | /* |
423 | * Newly created kthread was parked when the CPU was offline. | |
424 | * The binding was lost and we need to set it again. | |
425 | */ | |
f2530dc7 TG |
426 | if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags)) |
427 | __kthread_bind(k, kthread->cpu, TASK_PARKED); | |
428 | wake_up_state(k, TASK_PARKED); | |
429 | } | |
430 | } | |
431 | ||
2a1d4460 TG |
432 | /** |
433 | * kthread_unpark - unpark a thread created by kthread_create(). | |
434 | * @k: thread created by kthread_create(). | |
435 | * | |
436 | * Sets kthread_should_park() for @k to return false, wakes it, and | |
437 | * waits for it to return. If the thread is marked percpu then its | |
438 | * bound to the cpu again. | |
439 | */ | |
440 | void kthread_unpark(struct task_struct *k) | |
441 | { | |
b5c5442b | 442 | struct kthread *kthread = to_live_kthread(k); |
2a1d4460 | 443 | |
f2530dc7 TG |
444 | if (kthread) |
445 | __kthread_unpark(k, kthread); | |
2a1d4460 | 446 | } |
18896451 | 447 | EXPORT_SYMBOL_GPL(kthread_unpark); |
2a1d4460 TG |
448 | |
449 | /** | |
450 | * kthread_park - park a thread created by kthread_create(). | |
451 | * @k: thread created by kthread_create(). | |
452 | * | |
453 | * Sets kthread_should_park() for @k to return true, wakes it, and | |
454 | * waits for it to return. This can also be called after kthread_create() | |
455 | * instead of calling wake_up_process(): the thread will park without | |
456 | * calling threadfn(). | |
457 | * | |
458 | * Returns 0 if the thread is parked, -ENOSYS if the thread exited. | |
459 | * If called by the kthread itself just the park bit is set. | |
460 | */ | |
461 | int kthread_park(struct task_struct *k) | |
462 | { | |
b5c5442b | 463 | struct kthread *kthread = to_live_kthread(k); |
2a1d4460 TG |
464 | int ret = -ENOSYS; |
465 | ||
466 | if (kthread) { | |
467 | if (!test_bit(KTHREAD_IS_PARKED, &kthread->flags)) { | |
468 | set_bit(KTHREAD_SHOULD_PARK, &kthread->flags); | |
469 | if (k != current) { | |
470 | wake_up_process(k); | |
471 | wait_for_completion(&kthread->parked); | |
472 | } | |
473 | } | |
474 | ret = 0; | |
475 | } | |
2a1d4460 TG |
476 | return ret; |
477 | } | |
18896451 | 478 | EXPORT_SYMBOL_GPL(kthread_park); |
2a1d4460 | 479 | |
9e37bd30 RD |
480 | /** |
481 | * kthread_stop - stop a thread created by kthread_create(). | |
482 | * @k: thread created by kthread_create(). | |
483 | * | |
484 | * Sets kthread_should_stop() for @k to return true, wakes it, and | |
9ae26027 ON |
485 | * waits for it to exit. This can also be called after kthread_create() |
486 | * instead of calling wake_up_process(): the thread will exit without | |
487 | * calling threadfn(). | |
488 | * | |
489 | * If threadfn() may call do_exit() itself, the caller must ensure | |
490 | * task_struct can't go away. | |
9e37bd30 RD |
491 | * |
492 | * Returns the result of threadfn(), or %-EINTR if wake_up_process() | |
493 | * was never called. | |
494 | */ | |
1da177e4 LT |
495 | int kthread_stop(struct task_struct *k) |
496 | { | |
b5c5442b | 497 | struct kthread *kthread; |
1da177e4 LT |
498 | int ret; |
499 | ||
0a16b607 | 500 | trace_sched_kthread_stop(k); |
b5c5442b ON |
501 | |
502 | get_task_struct(k); | |
503 | kthread = to_live_kthread(k); | |
2a1d4460 TG |
504 | if (kthread) { |
505 | set_bit(KTHREAD_SHOULD_STOP, &kthread->flags); | |
f2530dc7 | 506 | __kthread_unpark(k, kthread); |
63706172 ON |
507 | wake_up_process(k); |
508 | wait_for_completion(&kthread->exited); | |
509 | } | |
510 | ret = k->exit_code; | |
1da177e4 | 511 | put_task_struct(k); |
0a16b607 | 512 | |
b5c5442b | 513 | trace_sched_kthread_stop_ret(ret); |
1da177e4 LT |
514 | return ret; |
515 | } | |
52e92e57 | 516 | EXPORT_SYMBOL(kthread_stop); |
1da177e4 | 517 | |
e804a4a4 | 518 | int kthreadd(void *unused) |
1da177e4 | 519 | { |
73c27992 | 520 | struct task_struct *tsk = current; |
1da177e4 | 521 | |
e804a4a4 | 522 | /* Setup a clean context for our children to inherit. */ |
73c27992 | 523 | set_task_comm(tsk, "kthreadd"); |
10ab825b | 524 | ignore_signals(tsk); |
1a2142af | 525 | set_cpus_allowed_ptr(tsk, cpu_all_mask); |
aee4faa4 | 526 | set_mems_allowed(node_states[N_MEMORY]); |
73c27992 | 527 | |
34b087e4 | 528 | current->flags |= PF_NOFREEZE; |
73c27992 EB |
529 | |
530 | for (;;) { | |
531 | set_current_state(TASK_INTERRUPTIBLE); | |
532 | if (list_empty(&kthread_create_list)) | |
533 | schedule(); | |
534 | __set_current_state(TASK_RUNNING); | |
535 | ||
536 | spin_lock(&kthread_create_lock); | |
537 | while (!list_empty(&kthread_create_list)) { | |
538 | struct kthread_create_info *create; | |
539 | ||
540 | create = list_entry(kthread_create_list.next, | |
541 | struct kthread_create_info, list); | |
542 | list_del_init(&create->list); | |
543 | spin_unlock(&kthread_create_lock); | |
544 | ||
545 | create_kthread(create); | |
546 | ||
547 | spin_lock(&kthread_create_lock); | |
548 | } | |
549 | spin_unlock(&kthread_create_lock); | |
550 | } | |
551 | ||
552 | return 0; | |
553 | } | |
b56c0d89 | 554 | |
8c03cbe6 | 555 | void __kthread_init_worker(struct kthread_worker *worker, |
4f32e9b1 YZ |
556 | const char *name, |
557 | struct lock_class_key *key) | |
558 | { | |
559 | spin_lock_init(&worker->lock); | |
560 | lockdep_set_class_and_name(&worker->lock, key, name); | |
561 | INIT_LIST_HEAD(&worker->work_list); | |
05defd8e | 562 | INIT_LIST_HEAD(&worker->delayed_work_list); |
4f32e9b1 YZ |
563 | worker->task = NULL; |
564 | } | |
8c03cbe6 | 565 | EXPORT_SYMBOL_GPL(__kthread_init_worker); |
4f32e9b1 | 566 | |
b56c0d89 TH |
567 | /** |
568 | * kthread_worker_fn - kthread function to process kthread_worker | |
569 | * @worker_ptr: pointer to initialized kthread_worker | |
570 | * | |
04555f91 PM |
571 | * This function implements the main cycle of kthread worker. It processes |
572 | * work_list until it is stopped with kthread_stop(). It sleeps when the queue | |
573 | * is empty. | |
b56c0d89 | 574 | * |
04555f91 PM |
575 | * The works are not allowed to keep any locks, disable preemption or interrupts |
576 | * when they finish. There is defined a safe point for freezing when one work | |
577 | * finishes and before a new one is started. | |
98c787c8 PM |
578 | * |
579 | * Also the works must not be handled by more than one worker at the same time, | |
580 | * see also kthread_queue_work(). | |
b56c0d89 TH |
581 | */ |
582 | int kthread_worker_fn(void *worker_ptr) | |
583 | { | |
584 | struct kthread_worker *worker = worker_ptr; | |
585 | struct kthread_work *work; | |
586 | ||
04555f91 PM |
587 | /* |
588 | * FIXME: Update the check and remove the assignment when all kthread | |
589 | * worker users are created using kthread_create_worker*() functions. | |
590 | */ | |
591 | WARN_ON(worker->task && worker->task != current); | |
b56c0d89 TH |
592 | worker->task = current; |
593 | repeat: | |
594 | set_current_state(TASK_INTERRUPTIBLE); /* mb paired w/ kthread_stop */ | |
595 | ||
596 | if (kthread_should_stop()) { | |
597 | __set_current_state(TASK_RUNNING); | |
598 | spin_lock_irq(&worker->lock); | |
599 | worker->task = NULL; | |
600 | spin_unlock_irq(&worker->lock); | |
601 | return 0; | |
602 | } | |
603 | ||
604 | work = NULL; | |
605 | spin_lock_irq(&worker->lock); | |
606 | if (!list_empty(&worker->work_list)) { | |
607 | work = list_first_entry(&worker->work_list, | |
608 | struct kthread_work, node); | |
609 | list_del_init(&work->node); | |
610 | } | |
46f3d976 | 611 | worker->current_work = work; |
b56c0d89 TH |
612 | spin_unlock_irq(&worker->lock); |
613 | ||
614 | if (work) { | |
615 | __set_current_state(TASK_RUNNING); | |
616 | work->func(work); | |
b56c0d89 TH |
617 | } else if (!freezing(current)) |
618 | schedule(); | |
619 | ||
620 | try_to_freeze(); | |
621 | goto repeat; | |
622 | } | |
623 | EXPORT_SYMBOL_GPL(kthread_worker_fn); | |
624 | ||
04555f91 PM |
625 | static struct kthread_worker * |
626 | __kthread_create_worker(int cpu, const char namefmt[], va_list args) | |
627 | { | |
628 | struct kthread_worker *worker; | |
629 | struct task_struct *task; | |
630 | ||
631 | worker = kzalloc(sizeof(*worker), GFP_KERNEL); | |
632 | if (!worker) | |
633 | return ERR_PTR(-ENOMEM); | |
634 | ||
635 | kthread_init_worker(worker); | |
636 | ||
637 | if (cpu >= 0) { | |
638 | char name[TASK_COMM_LEN]; | |
639 | ||
640 | /* | |
641 | * kthread_create_worker_on_cpu() allows to pass a generic | |
642 | * namefmt in compare with kthread_create_on_cpu. We need | |
643 | * to format it here. | |
644 | */ | |
645 | vsnprintf(name, sizeof(name), namefmt, args); | |
646 | task = kthread_create_on_cpu(kthread_worker_fn, worker, | |
647 | cpu, name); | |
648 | } else { | |
649 | task = __kthread_create_on_node(kthread_worker_fn, worker, | |
650 | -1, namefmt, args); | |
651 | } | |
652 | ||
653 | if (IS_ERR(task)) | |
654 | goto fail_task; | |
655 | ||
656 | worker->task = task; | |
657 | wake_up_process(task); | |
658 | return worker; | |
659 | ||
660 | fail_task: | |
661 | kfree(worker); | |
662 | return ERR_CAST(task); | |
663 | } | |
664 | ||
665 | /** | |
666 | * kthread_create_worker - create a kthread worker | |
667 | * @namefmt: printf-style name for the kthread worker (task). | |
668 | * | |
669 | * Returns a pointer to the allocated worker on success, ERR_PTR(-ENOMEM) | |
670 | * when the needed structures could not get allocated, and ERR_PTR(-EINTR) | |
671 | * when the worker was SIGKILLed. | |
672 | */ | |
673 | struct kthread_worker * | |
674 | kthread_create_worker(const char namefmt[], ...) | |
675 | { | |
676 | struct kthread_worker *worker; | |
677 | va_list args; | |
678 | ||
679 | va_start(args, namefmt); | |
680 | worker = __kthread_create_worker(-1, namefmt, args); | |
681 | va_end(args); | |
682 | ||
683 | return worker; | |
684 | } | |
685 | EXPORT_SYMBOL(kthread_create_worker); | |
686 | ||
687 | /** | |
688 | * kthread_create_worker_on_cpu - create a kthread worker and bind it | |
689 | * it to a given CPU and the associated NUMA node. | |
690 | * @cpu: CPU number | |
691 | * @namefmt: printf-style name for the kthread worker (task). | |
692 | * | |
693 | * Use a valid CPU number if you want to bind the kthread worker | |
694 | * to the given CPU and the associated NUMA node. | |
695 | * | |
696 | * A good practice is to add the cpu number also into the worker name. | |
697 | * For example, use kthread_create_worker_on_cpu(cpu, "helper/%d", cpu). | |
698 | * | |
699 | * Returns a pointer to the allocated worker on success, ERR_PTR(-ENOMEM) | |
700 | * when the needed structures could not get allocated, and ERR_PTR(-EINTR) | |
701 | * when the worker was SIGKILLed. | |
702 | */ | |
703 | struct kthread_worker * | |
704 | kthread_create_worker_on_cpu(int cpu, const char namefmt[], ...) | |
705 | { | |
706 | struct kthread_worker *worker; | |
707 | va_list args; | |
708 | ||
709 | va_start(args, namefmt); | |
710 | worker = __kthread_create_worker(cpu, namefmt, args); | |
711 | va_end(args); | |
712 | ||
713 | return worker; | |
714 | } | |
715 | EXPORT_SYMBOL(kthread_create_worker_on_cpu); | |
716 | ||
a105b741 PM |
717 | /* |
718 | * Returns true when the work could not be queued at the moment. | |
719 | * It happens when it is already pending in a worker list | |
720 | * or when it is being cancelled. | |
721 | */ | |
722 | static inline bool queuing_blocked(struct kthread_worker *worker, | |
723 | struct kthread_work *work) | |
724 | { | |
725 | lockdep_assert_held(&worker->lock); | |
726 | ||
727 | return !list_empty(&work->node) || work->canceling; | |
728 | } | |
729 | ||
98c787c8 PM |
730 | static void kthread_insert_work_sanity_check(struct kthread_worker *worker, |
731 | struct kthread_work *work) | |
732 | { | |
733 | lockdep_assert_held(&worker->lock); | |
734 | WARN_ON_ONCE(!list_empty(&work->node)); | |
735 | /* Do not use a work with >1 worker, see kthread_queue_work() */ | |
736 | WARN_ON_ONCE(work->worker && work->worker != worker); | |
737 | } | |
738 | ||
9a2e03d8 | 739 | /* insert @work before @pos in @worker */ |
8c03cbe6 | 740 | static void kthread_insert_work(struct kthread_worker *worker, |
98c787c8 PM |
741 | struct kthread_work *work, |
742 | struct list_head *pos) | |
9a2e03d8 | 743 | { |
98c787c8 | 744 | kthread_insert_work_sanity_check(worker, work); |
9a2e03d8 TH |
745 | |
746 | list_add_tail(&work->node, pos); | |
46f3d976 | 747 | work->worker = worker; |
ed1403ec | 748 | if (!worker->current_work && likely(worker->task)) |
9a2e03d8 TH |
749 | wake_up_process(worker->task); |
750 | } | |
751 | ||
b56c0d89 | 752 | /** |
8c03cbe6 | 753 | * kthread_queue_work - queue a kthread_work |
b56c0d89 TH |
754 | * @worker: target kthread_worker |
755 | * @work: kthread_work to queue | |
756 | * | |
757 | * Queue @work to work processor @task for async execution. @task | |
758 | * must have been created with kthread_worker_create(). Returns %true | |
759 | * if @work was successfully queued, %false if it was already pending. | |
98c787c8 PM |
760 | * |
761 | * Reinitialize the work if it needs to be used by another worker. | |
762 | * For example, when the worker was stopped and started again. | |
b56c0d89 | 763 | */ |
8c03cbe6 | 764 | bool kthread_queue_work(struct kthread_worker *worker, |
b56c0d89 TH |
765 | struct kthread_work *work) |
766 | { | |
767 | bool ret = false; | |
768 | unsigned long flags; | |
769 | ||
770 | spin_lock_irqsave(&worker->lock, flags); | |
a105b741 | 771 | if (!queuing_blocked(worker, work)) { |
8c03cbe6 | 772 | kthread_insert_work(worker, work, &worker->work_list); |
b56c0d89 TH |
773 | ret = true; |
774 | } | |
775 | spin_unlock_irqrestore(&worker->lock, flags); | |
776 | return ret; | |
777 | } | |
8c03cbe6 | 778 | EXPORT_SYMBOL_GPL(kthread_queue_work); |
b56c0d89 | 779 | |
05defd8e PM |
780 | /** |
781 | * kthread_delayed_work_timer_fn - callback that queues the associated kthread | |
782 | * delayed work when the timer expires. | |
783 | * @__data: pointer to the data associated with the timer | |
784 | * | |
785 | * The format of the function is defined by struct timer_list. | |
786 | * It should have been called from irqsafe timer with irq already off. | |
787 | */ | |
788 | void kthread_delayed_work_timer_fn(unsigned long __data) | |
789 | { | |
790 | struct kthread_delayed_work *dwork = | |
791 | (struct kthread_delayed_work *)__data; | |
792 | struct kthread_work *work = &dwork->work; | |
793 | struct kthread_worker *worker = work->worker; | |
794 | ||
795 | /* | |
796 | * This might happen when a pending work is reinitialized. | |
797 | * It means that it is used a wrong way. | |
798 | */ | |
799 | if (WARN_ON_ONCE(!worker)) | |
800 | return; | |
801 | ||
802 | spin_lock(&worker->lock); | |
803 | /* Work must not be used with >1 worker, see kthread_queue_work(). */ | |
804 | WARN_ON_ONCE(work->worker != worker); | |
805 | ||
806 | /* Move the work from worker->delayed_work_list. */ | |
807 | WARN_ON_ONCE(list_empty(&work->node)); | |
808 | list_del_init(&work->node); | |
809 | kthread_insert_work(worker, work, &worker->work_list); | |
810 | ||
811 | spin_unlock(&worker->lock); | |
812 | } | |
813 | EXPORT_SYMBOL(kthread_delayed_work_timer_fn); | |
814 | ||
815 | void __kthread_queue_delayed_work(struct kthread_worker *worker, | |
816 | struct kthread_delayed_work *dwork, | |
817 | unsigned long delay) | |
818 | { | |
819 | struct timer_list *timer = &dwork->timer; | |
820 | struct kthread_work *work = &dwork->work; | |
821 | ||
822 | WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn || | |
823 | timer->data != (unsigned long)dwork); | |
824 | ||
825 | /* | |
826 | * If @delay is 0, queue @dwork->work immediately. This is for | |
827 | * both optimization and correctness. The earliest @timer can | |
828 | * expire is on the closest next tick and delayed_work users depend | |
829 | * on that there's no such delay when @delay is 0. | |
830 | */ | |
831 | if (!delay) { | |
832 | kthread_insert_work(worker, work, &worker->work_list); | |
833 | return; | |
834 | } | |
835 | ||
836 | /* Be paranoid and try to detect possible races already now. */ | |
837 | kthread_insert_work_sanity_check(worker, work); | |
838 | ||
839 | list_add(&work->node, &worker->delayed_work_list); | |
840 | work->worker = worker; | |
841 | timer_stats_timer_set_start_info(&dwork->timer); | |
842 | timer->expires = jiffies + delay; | |
843 | add_timer(timer); | |
844 | } | |
845 | ||
846 | /** | |
847 | * kthread_queue_delayed_work - queue the associated kthread work | |
848 | * after a delay. | |
849 | * @worker: target kthread_worker | |
850 | * @dwork: kthread_delayed_work to queue | |
851 | * @delay: number of jiffies to wait before queuing | |
852 | * | |
853 | * If the work has not been pending it starts a timer that will queue | |
854 | * the work after the given @delay. If @delay is zero, it queues the | |
855 | * work immediately. | |
856 | * | |
857 | * Return: %false if the @work has already been pending. It means that | |
858 | * either the timer was running or the work was queued. It returns %true | |
859 | * otherwise. | |
860 | */ | |
861 | bool kthread_queue_delayed_work(struct kthread_worker *worker, | |
862 | struct kthread_delayed_work *dwork, | |
863 | unsigned long delay) | |
864 | { | |
865 | struct kthread_work *work = &dwork->work; | |
866 | unsigned long flags; | |
867 | bool ret = false; | |
868 | ||
869 | spin_lock_irqsave(&worker->lock, flags); | |
870 | ||
a105b741 | 871 | if (!queuing_blocked(worker, work)) { |
05defd8e PM |
872 | __kthread_queue_delayed_work(worker, dwork, delay); |
873 | ret = true; | |
874 | } | |
875 | ||
876 | spin_unlock_irqrestore(&worker->lock, flags); | |
877 | return ret; | |
878 | } | |
879 | EXPORT_SYMBOL_GPL(kthread_queue_delayed_work); | |
880 | ||
9a2e03d8 TH |
881 | struct kthread_flush_work { |
882 | struct kthread_work work; | |
883 | struct completion done; | |
884 | }; | |
885 | ||
886 | static void kthread_flush_work_fn(struct kthread_work *work) | |
887 | { | |
888 | struct kthread_flush_work *fwork = | |
889 | container_of(work, struct kthread_flush_work, work); | |
890 | complete(&fwork->done); | |
891 | } | |
892 | ||
b56c0d89 | 893 | /** |
8c03cbe6 | 894 | * kthread_flush_work - flush a kthread_work |
b56c0d89 TH |
895 | * @work: work to flush |
896 | * | |
897 | * If @work is queued or executing, wait for it to finish execution. | |
898 | */ | |
8c03cbe6 | 899 | void kthread_flush_work(struct kthread_work *work) |
b56c0d89 | 900 | { |
46f3d976 TH |
901 | struct kthread_flush_work fwork = { |
902 | KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn), | |
903 | COMPLETION_INITIALIZER_ONSTACK(fwork.done), | |
904 | }; | |
905 | struct kthread_worker *worker; | |
906 | bool noop = false; | |
907 | ||
46f3d976 TH |
908 | worker = work->worker; |
909 | if (!worker) | |
910 | return; | |
b56c0d89 | 911 | |
46f3d976 | 912 | spin_lock_irq(&worker->lock); |
98c787c8 PM |
913 | /* Work must not be used with >1 worker, see kthread_queue_work(). */ |
914 | WARN_ON_ONCE(work->worker != worker); | |
b56c0d89 | 915 | |
46f3d976 | 916 | if (!list_empty(&work->node)) |
8c03cbe6 | 917 | kthread_insert_work(worker, &fwork.work, work->node.next); |
46f3d976 | 918 | else if (worker->current_work == work) |
8c03cbe6 PM |
919 | kthread_insert_work(worker, &fwork.work, |
920 | worker->work_list.next); | |
46f3d976 TH |
921 | else |
922 | noop = true; | |
b56c0d89 | 923 | |
46f3d976 | 924 | spin_unlock_irq(&worker->lock); |
b56c0d89 | 925 | |
46f3d976 TH |
926 | if (!noop) |
927 | wait_for_completion(&fwork.done); | |
b56c0d89 | 928 | } |
8c03cbe6 | 929 | EXPORT_SYMBOL_GPL(kthread_flush_work); |
b56c0d89 | 930 | |
a105b741 PM |
931 | /* |
932 | * This function removes the work from the worker queue. Also it makes sure | |
933 | * that it won't get queued later via the delayed work's timer. | |
934 | * | |
935 | * The work might still be in use when this function finishes. See the | |
936 | * current_work proceed by the worker. | |
937 | * | |
938 | * Return: %true if @work was pending and successfully canceled, | |
939 | * %false if @work was not pending | |
940 | */ | |
941 | static bool __kthread_cancel_work(struct kthread_work *work, bool is_dwork, | |
942 | unsigned long *flags) | |
943 | { | |
944 | /* Try to cancel the timer if exists. */ | |
945 | if (is_dwork) { | |
946 | struct kthread_delayed_work *dwork = | |
947 | container_of(work, struct kthread_delayed_work, work); | |
948 | struct kthread_worker *worker = work->worker; | |
949 | ||
950 | /* | |
951 | * del_timer_sync() must be called to make sure that the timer | |
952 | * callback is not running. The lock must be temporary released | |
953 | * to avoid a deadlock with the callback. In the meantime, | |
954 | * any queuing is blocked by setting the canceling counter. | |
955 | */ | |
956 | work->canceling++; | |
957 | spin_unlock_irqrestore(&worker->lock, *flags); | |
958 | del_timer_sync(&dwork->timer); | |
959 | spin_lock_irqsave(&worker->lock, *flags); | |
960 | work->canceling--; | |
961 | } | |
962 | ||
963 | /* | |
964 | * Try to remove the work from a worker list. It might either | |
965 | * be from worker->work_list or from worker->delayed_work_list. | |
966 | */ | |
967 | if (!list_empty(&work->node)) { | |
968 | list_del_init(&work->node); | |
969 | return true; | |
970 | } | |
971 | ||
972 | return false; | |
973 | } | |
974 | ||
3432b888 PM |
975 | /** |
976 | * kthread_mod_delayed_work - modify delay of or queue a kthread delayed work | |
977 | * @worker: kthread worker to use | |
978 | * @dwork: kthread delayed work to queue | |
979 | * @delay: number of jiffies to wait before queuing | |
980 | * | |
981 | * If @dwork is idle, equivalent to kthread_queue_delayed_work(). Otherwise, | |
982 | * modify @dwork's timer so that it expires after @delay. If @delay is zero, | |
983 | * @work is guaranteed to be queued immediately. | |
984 | * | |
985 | * Return: %true if @dwork was pending and its timer was modified, | |
986 | * %false otherwise. | |
987 | * | |
988 | * A special case is when the work is being canceled in parallel. | |
989 | * It might be caused either by the real kthread_cancel_delayed_work_sync() | |
990 | * or yet another kthread_mod_delayed_work() call. We let the other command | |
991 | * win and return %false here. The caller is supposed to synchronize these | |
992 | * operations a reasonable way. | |
993 | * | |
994 | * This function is safe to call from any context including IRQ handler. | |
995 | * See __kthread_cancel_work() and kthread_delayed_work_timer_fn() | |
996 | * for details. | |
997 | */ | |
998 | bool kthread_mod_delayed_work(struct kthread_worker *worker, | |
999 | struct kthread_delayed_work *dwork, | |
1000 | unsigned long delay) | |
1001 | { | |
1002 | struct kthread_work *work = &dwork->work; | |
1003 | unsigned long flags; | |
1004 | int ret = false; | |
1005 | ||
1006 | spin_lock_irqsave(&worker->lock, flags); | |
1007 | ||
1008 | /* Do not bother with canceling when never queued. */ | |
1009 | if (!work->worker) | |
1010 | goto fast_queue; | |
1011 | ||
1012 | /* Work must not be used with >1 worker, see kthread_queue_work() */ | |
1013 | WARN_ON_ONCE(work->worker != worker); | |
1014 | ||
1015 | /* Do not fight with another command that is canceling this work. */ | |
1016 | if (work->canceling) | |
1017 | goto out; | |
1018 | ||
1019 | ret = __kthread_cancel_work(work, true, &flags); | |
1020 | fast_queue: | |
1021 | __kthread_queue_delayed_work(worker, dwork, delay); | |
1022 | out: | |
1023 | spin_unlock_irqrestore(&worker->lock, flags); | |
1024 | return ret; | |
1025 | } | |
1026 | EXPORT_SYMBOL_GPL(kthread_mod_delayed_work); | |
1027 | ||
a105b741 PM |
1028 | static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork) |
1029 | { | |
1030 | struct kthread_worker *worker = work->worker; | |
1031 | unsigned long flags; | |
1032 | int ret = false; | |
1033 | ||
1034 | if (!worker) | |
1035 | goto out; | |
1036 | ||
1037 | spin_lock_irqsave(&worker->lock, flags); | |
1038 | /* Work must not be used with >1 worker, see kthread_queue_work(). */ | |
1039 | WARN_ON_ONCE(work->worker != worker); | |
1040 | ||
1041 | ret = __kthread_cancel_work(work, is_dwork, &flags); | |
1042 | ||
1043 | if (worker->current_work != work) | |
1044 | goto out_fast; | |
1045 | ||
1046 | /* | |
1047 | * The work is in progress and we need to wait with the lock released. | |
1048 | * In the meantime, block any queuing by setting the canceling counter. | |
1049 | */ | |
1050 | work->canceling++; | |
1051 | spin_unlock_irqrestore(&worker->lock, flags); | |
1052 | kthread_flush_work(work); | |
1053 | spin_lock_irqsave(&worker->lock, flags); | |
1054 | work->canceling--; | |
1055 | ||
1056 | out_fast: | |
1057 | spin_unlock_irqrestore(&worker->lock, flags); | |
1058 | out: | |
1059 | return ret; | |
1060 | } | |
1061 | ||
1062 | /** | |
1063 | * kthread_cancel_work_sync - cancel a kthread work and wait for it to finish | |
1064 | * @work: the kthread work to cancel | |
1065 | * | |
1066 | * Cancel @work and wait for its execution to finish. This function | |
1067 | * can be used even if the work re-queues itself. On return from this | |
1068 | * function, @work is guaranteed to be not pending or executing on any CPU. | |
1069 | * | |
1070 | * kthread_cancel_work_sync(&delayed_work->work) must not be used for | |
1071 | * delayed_work's. Use kthread_cancel_delayed_work_sync() instead. | |
1072 | * | |
1073 | * The caller must ensure that the worker on which @work was last | |
1074 | * queued can't be destroyed before this function returns. | |
1075 | * | |
1076 | * Return: %true if @work was pending, %false otherwise. | |
1077 | */ | |
1078 | bool kthread_cancel_work_sync(struct kthread_work *work) | |
1079 | { | |
1080 | return __kthread_cancel_work_sync(work, false); | |
1081 | } | |
1082 | EXPORT_SYMBOL_GPL(kthread_cancel_work_sync); | |
1083 | ||
1084 | /** | |
1085 | * kthread_cancel_delayed_work_sync - cancel a kthread delayed work and | |
1086 | * wait for it to finish. | |
1087 | * @dwork: the kthread delayed work to cancel | |
1088 | * | |
1089 | * This is kthread_cancel_work_sync() for delayed works. | |
1090 | * | |
1091 | * Return: %true if @dwork was pending, %false otherwise. | |
1092 | */ | |
1093 | bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *dwork) | |
1094 | { | |
1095 | return __kthread_cancel_work_sync(&dwork->work, true); | |
1096 | } | |
1097 | EXPORT_SYMBOL_GPL(kthread_cancel_delayed_work_sync); | |
1098 | ||
b56c0d89 | 1099 | /** |
8c03cbe6 | 1100 | * kthread_flush_worker - flush all current works on a kthread_worker |
b56c0d89 TH |
1101 | * @worker: worker to flush |
1102 | * | |
1103 | * Wait until all currently executing or pending works on @worker are | |
1104 | * finished. | |
1105 | */ | |
8c03cbe6 | 1106 | void kthread_flush_worker(struct kthread_worker *worker) |
b56c0d89 TH |
1107 | { |
1108 | struct kthread_flush_work fwork = { | |
1109 | KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn), | |
1110 | COMPLETION_INITIALIZER_ONSTACK(fwork.done), | |
1111 | }; | |
1112 | ||
8c03cbe6 | 1113 | kthread_queue_work(worker, &fwork.work); |
b56c0d89 TH |
1114 | wait_for_completion(&fwork.done); |
1115 | } | |
8c03cbe6 | 1116 | EXPORT_SYMBOL_GPL(kthread_flush_worker); |
c5999abe PM |
1117 | |
1118 | /** | |
1119 | * kthread_destroy_worker - destroy a kthread worker | |
1120 | * @worker: worker to be destroyed | |
1121 | * | |
1122 | * Flush and destroy @worker. The simple flush is enough because the kthread | |
1123 | * worker API is used only in trivial scenarios. There are no multi-step state | |
1124 | * machines needed. | |
1125 | */ | |
1126 | void kthread_destroy_worker(struct kthread_worker *worker) | |
1127 | { | |
1128 | struct task_struct *task; | |
1129 | ||
1130 | task = worker->task; | |
1131 | if (WARN_ON(!task)) | |
1132 | return; | |
1133 | ||
1134 | kthread_flush_worker(worker); | |
1135 | kthread_stop(task); | |
1136 | WARN_ON(!list_empty(&worker->work_list)); | |
1137 | kfree(worker); | |
1138 | } | |
1139 | EXPORT_SYMBOL(kthread_destroy_worker); |