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> | |
ad8d75ff | 19 | #include <trace/events/sched.h> |
1da177e4 | 20 | |
73c27992 EB |
21 | static DEFINE_SPINLOCK(kthread_create_lock); |
22 | static LIST_HEAD(kthread_create_list); | |
23 | struct task_struct *kthreadd_task; | |
1da177e4 LT |
24 | |
25 | struct kthread_create_info | |
26 | { | |
73c27992 | 27 | /* Information passed to kthread() from kthreadd. */ |
1da177e4 LT |
28 | int (*threadfn)(void *data); |
29 | void *data; | |
207205a2 | 30 | int node; |
1da177e4 | 31 | |
73c27992 | 32 | /* Result passed back to kthread_create() from kthreadd. */ |
1da177e4 LT |
33 | struct task_struct *result; |
34 | struct completion done; | |
65f27f38 | 35 | |
73c27992 | 36 | struct list_head list; |
1da177e4 LT |
37 | }; |
38 | ||
63706172 | 39 | struct kthread { |
2a1d4460 TG |
40 | unsigned long flags; |
41 | unsigned int cpu; | |
82805ab7 | 42 | void *data; |
2a1d4460 | 43 | struct completion parked; |
63706172 | 44 | struct completion exited; |
1da177e4 LT |
45 | }; |
46 | ||
2a1d4460 TG |
47 | enum KTHREAD_BITS { |
48 | KTHREAD_IS_PER_CPU = 0, | |
49 | KTHREAD_SHOULD_STOP, | |
50 | KTHREAD_SHOULD_PARK, | |
51 | KTHREAD_IS_PARKED, | |
52 | }; | |
53 | ||
63706172 ON |
54 | #define to_kthread(tsk) \ |
55 | container_of((tsk)->vfork_done, struct kthread, exited) | |
1da177e4 | 56 | |
9e37bd30 RD |
57 | /** |
58 | * kthread_should_stop - should this kthread return now? | |
59 | * | |
72fd4a35 | 60 | * When someone calls kthread_stop() on your kthread, it will be woken |
9e37bd30 RD |
61 | * and this will return true. You should then return, and your return |
62 | * value will be passed through to kthread_stop(). | |
63 | */ | |
2a1d4460 | 64 | bool kthread_should_stop(void) |
1da177e4 | 65 | { |
2a1d4460 | 66 | return test_bit(KTHREAD_SHOULD_STOP, &to_kthread(current)->flags); |
1da177e4 LT |
67 | } |
68 | EXPORT_SYMBOL(kthread_should_stop); | |
69 | ||
2a1d4460 TG |
70 | /** |
71 | * kthread_should_park - should this kthread park now? | |
72 | * | |
73 | * When someone calls kthread_park() on your kthread, it will be woken | |
74 | * and this will return true. You should then do the necessary | |
75 | * cleanup and call kthread_parkme() | |
76 | * | |
77 | * Similar to kthread_should_stop(), but this keeps the thread alive | |
78 | * and in a park position. kthread_unpark() "restarts" the thread and | |
79 | * calls the thread function again. | |
80 | */ | |
81 | bool kthread_should_park(void) | |
82 | { | |
83 | return test_bit(KTHREAD_SHOULD_PARK, &to_kthread(current)->flags); | |
84 | } | |
85 | ||
8a32c441 TH |
86 | /** |
87 | * kthread_freezable_should_stop - should this freezable kthread return now? | |
88 | * @was_frozen: optional out parameter, indicates whether %current was frozen | |
89 | * | |
90 | * kthread_should_stop() for freezable kthreads, which will enter | |
91 | * refrigerator if necessary. This function is safe from kthread_stop() / | |
92 | * freezer deadlock and freezable kthreads should use this function instead | |
93 | * of calling try_to_freeze() directly. | |
94 | */ | |
95 | bool kthread_freezable_should_stop(bool *was_frozen) | |
96 | { | |
97 | bool frozen = false; | |
98 | ||
99 | might_sleep(); | |
100 | ||
101 | if (unlikely(freezing(current))) | |
102 | frozen = __refrigerator(true); | |
103 | ||
104 | if (was_frozen) | |
105 | *was_frozen = frozen; | |
106 | ||
107 | return kthread_should_stop(); | |
108 | } | |
109 | EXPORT_SYMBOL_GPL(kthread_freezable_should_stop); | |
110 | ||
82805ab7 TH |
111 | /** |
112 | * kthread_data - return data value specified on kthread creation | |
113 | * @task: kthread task in question | |
114 | * | |
115 | * Return the data value specified when kthread @task was created. | |
116 | * The caller is responsible for ensuring the validity of @task when | |
117 | * calling this function. | |
118 | */ | |
119 | void *kthread_data(struct task_struct *task) | |
120 | { | |
121 | return to_kthread(task)->data; | |
122 | } | |
123 | ||
2a1d4460 TG |
124 | static void __kthread_parkme(struct kthread *self) |
125 | { | |
126 | __set_current_state(TASK_INTERRUPTIBLE); | |
127 | while (test_bit(KTHREAD_SHOULD_PARK, &self->flags)) { | |
128 | if (!test_and_set_bit(KTHREAD_IS_PARKED, &self->flags)) | |
129 | complete(&self->parked); | |
130 | schedule(); | |
131 | __set_current_state(TASK_INTERRUPTIBLE); | |
132 | } | |
133 | clear_bit(KTHREAD_IS_PARKED, &self->flags); | |
134 | __set_current_state(TASK_RUNNING); | |
135 | } | |
136 | ||
137 | void kthread_parkme(void) | |
138 | { | |
139 | __kthread_parkme(to_kthread(current)); | |
140 | } | |
141 | ||
1da177e4 LT |
142 | static int kthread(void *_create) |
143 | { | |
63706172 | 144 | /* Copy data: it's on kthread's stack */ |
1da177e4 | 145 | struct kthread_create_info *create = _create; |
63706172 ON |
146 | int (*threadfn)(void *data) = create->threadfn; |
147 | void *data = create->data; | |
148 | struct kthread self; | |
149 | int ret; | |
1da177e4 | 150 | |
2a1d4460 | 151 | self.flags = 0; |
82805ab7 | 152 | self.data = data; |
63706172 | 153 | init_completion(&self.exited); |
2a1d4460 | 154 | init_completion(&self.parked); |
63706172 | 155 | current->vfork_done = &self.exited; |
1da177e4 | 156 | |
1da177e4 | 157 | /* OK, tell user we're spawned, wait for stop or wakeup */ |
a076e4bc | 158 | __set_current_state(TASK_UNINTERRUPTIBLE); |
3217ab97 | 159 | create->result = current; |
cdd140bd | 160 | complete(&create->done); |
1da177e4 LT |
161 | schedule(); |
162 | ||
63706172 | 163 | ret = -EINTR; |
1da177e4 | 164 | |
2a1d4460 TG |
165 | if (!test_bit(KTHREAD_SHOULD_STOP, &self.flags)) { |
166 | __kthread_parkme(&self); | |
167 | ret = threadfn(data); | |
168 | } | |
63706172 ON |
169 | /* we can't just return, we must preserve "self" on stack */ |
170 | do_exit(ret); | |
1da177e4 LT |
171 | } |
172 | ||
207205a2 ED |
173 | /* called from do_fork() to get node information for about to be created task */ |
174 | int tsk_fork_get_node(struct task_struct *tsk) | |
175 | { | |
176 | #ifdef CONFIG_NUMA | |
177 | if (tsk == kthreadd_task) | |
178 | return tsk->pref_node_fork; | |
179 | #endif | |
180 | return numa_node_id(); | |
181 | } | |
182 | ||
73c27992 | 183 | static void create_kthread(struct kthread_create_info *create) |
1da177e4 | 184 | { |
1da177e4 LT |
185 | int pid; |
186 | ||
207205a2 ED |
187 | #ifdef CONFIG_NUMA |
188 | current->pref_node_fork = create->node; | |
189 | #endif | |
1da177e4 LT |
190 | /* We want our own signal handler (we take no signals by default). */ |
191 | pid = kernel_thread(kthread, create, CLONE_FS | CLONE_FILES | SIGCHLD); | |
cdd140bd | 192 | if (pid < 0) { |
1da177e4 | 193 | create->result = ERR_PTR(pid); |
cdd140bd ON |
194 | complete(&create->done); |
195 | } | |
1da177e4 LT |
196 | } |
197 | ||
9e37bd30 | 198 | /** |
207205a2 | 199 | * kthread_create_on_node - create a kthread. |
9e37bd30 RD |
200 | * @threadfn: the function to run until signal_pending(current). |
201 | * @data: data ptr for @threadfn. | |
207205a2 | 202 | * @node: memory node number. |
9e37bd30 RD |
203 | * @namefmt: printf-style name for the thread. |
204 | * | |
205 | * Description: This helper function creates and names a kernel | |
206 | * thread. The thread will be stopped: use wake_up_process() to start | |
301ba045 | 207 | * it. See also kthread_run(). |
9e37bd30 | 208 | * |
207205a2 ED |
209 | * If thread is going to be bound on a particular cpu, give its node |
210 | * in @node, to get NUMA affinity for kthread stack, or else give -1. | |
9e37bd30 | 211 | * When woken, the thread will run @threadfn() with @data as its |
72fd4a35 | 212 | * argument. @threadfn() can either call do_exit() directly if it is a |
25985edc | 213 | * standalone thread for which no one will call kthread_stop(), or |
9e37bd30 RD |
214 | * return when 'kthread_should_stop()' is true (which means |
215 | * kthread_stop() has been called). The return value should be zero | |
216 | * or a negative error number; it will be passed to kthread_stop(). | |
217 | * | |
218 | * Returns a task_struct or ERR_PTR(-ENOMEM). | |
219 | */ | |
207205a2 | 220 | struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), |
2a1d4460 | 221 | void *data, int node, |
207205a2 ED |
222 | const char namefmt[], |
223 | ...) | |
1da177e4 LT |
224 | { |
225 | struct kthread_create_info create; | |
1da177e4 LT |
226 | |
227 | create.threadfn = threadfn; | |
228 | create.data = data; | |
207205a2 | 229 | create.node = node; |
1da177e4 | 230 | init_completion(&create.done); |
73c27992 EB |
231 | |
232 | spin_lock(&kthread_create_lock); | |
233 | list_add_tail(&create.list, &kthread_create_list); | |
73c27992 EB |
234 | spin_unlock(&kthread_create_lock); |
235 | ||
cbd9b67b | 236 | wake_up_process(kthreadd_task); |
73c27992 EB |
237 | wait_for_completion(&create.done); |
238 | ||
1da177e4 | 239 | if (!IS_ERR(create.result)) { |
c9b5f501 | 240 | static const struct sched_param param = { .sched_priority = 0 }; |
1da177e4 | 241 | va_list args; |
1c99315b | 242 | |
1da177e4 LT |
243 | va_start(args, namefmt); |
244 | vsnprintf(create.result->comm, sizeof(create.result->comm), | |
245 | namefmt, args); | |
246 | va_end(args); | |
1c99315b ON |
247 | /* |
248 | * root may have changed our (kthreadd's) priority or CPU mask. | |
249 | * The kernel thread should not inherit these properties. | |
250 | */ | |
251 | sched_setscheduler_nocheck(create.result, SCHED_NORMAL, ¶m); | |
1c99315b | 252 | set_cpus_allowed_ptr(create.result, cpu_all_mask); |
1da177e4 | 253 | } |
1da177e4 LT |
254 | return create.result; |
255 | } | |
207205a2 | 256 | EXPORT_SYMBOL(kthread_create_on_node); |
1da177e4 | 257 | |
2a1d4460 TG |
258 | static void __kthread_bind(struct task_struct *p, unsigned int cpu) |
259 | { | |
260 | /* It's safe because the task is inactive. */ | |
261 | do_set_cpus_allowed(p, cpumask_of(cpu)); | |
262 | p->flags |= PF_THREAD_BOUND; | |
263 | } | |
264 | ||
881232b7 PZ |
265 | /** |
266 | * kthread_bind - bind a just-created kthread to a cpu. | |
267 | * @p: thread created by kthread_create(). | |
268 | * @cpu: cpu (might not be online, must be possible) for @k to run on. | |
269 | * | |
270 | * Description: This function is equivalent to set_cpus_allowed(), | |
271 | * except that @cpu doesn't need to be online, and the thread must be | |
272 | * stopped (i.e., just returned from kthread_create()). | |
273 | */ | |
274 | void kthread_bind(struct task_struct *p, unsigned int cpu) | |
275 | { | |
276 | /* Must have done schedule() in kthread() before we set_task_cpu */ | |
277 | if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) { | |
278 | WARN_ON(1); | |
279 | return; | |
280 | } | |
2a1d4460 | 281 | __kthread_bind(p, cpu); |
881232b7 PZ |
282 | } |
283 | EXPORT_SYMBOL(kthread_bind); | |
284 | ||
2a1d4460 TG |
285 | /** |
286 | * kthread_create_on_cpu - Create a cpu bound kthread | |
287 | * @threadfn: the function to run until signal_pending(current). | |
288 | * @data: data ptr for @threadfn. | |
289 | * @cpu: The cpu on which the thread should be bound, | |
290 | * @namefmt: printf-style name for the thread. Format is restricted | |
291 | * to "name.*%u". Code fills in cpu number. | |
292 | * | |
293 | * Description: This helper function creates and names a kernel thread | |
294 | * The thread will be woken and put into park mode. | |
295 | */ | |
296 | struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data), | |
297 | void *data, unsigned int cpu, | |
298 | const char *namefmt) | |
299 | { | |
300 | struct task_struct *p; | |
301 | ||
302 | p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt, | |
303 | cpu); | |
304 | if (IS_ERR(p)) | |
305 | return p; | |
306 | set_bit(KTHREAD_IS_PER_CPU, &to_kthread(p)->flags); | |
307 | to_kthread(p)->cpu = cpu; | |
308 | /* Park the thread to get it out of TASK_UNINTERRUPTIBLE state */ | |
309 | kthread_park(p); | |
310 | return p; | |
311 | } | |
312 | ||
313 | static struct kthread *task_get_live_kthread(struct task_struct *k) | |
314 | { | |
315 | struct kthread *kthread; | |
316 | ||
317 | get_task_struct(k); | |
318 | kthread = to_kthread(k); | |
319 | /* It might have exited */ | |
320 | barrier(); | |
321 | if (k->vfork_done != NULL) | |
322 | return kthread; | |
323 | return NULL; | |
324 | } | |
325 | ||
326 | /** | |
327 | * kthread_unpark - unpark a thread created by kthread_create(). | |
328 | * @k: thread created by kthread_create(). | |
329 | * | |
330 | * Sets kthread_should_park() for @k to return false, wakes it, and | |
331 | * waits for it to return. If the thread is marked percpu then its | |
332 | * bound to the cpu again. | |
333 | */ | |
334 | void kthread_unpark(struct task_struct *k) | |
335 | { | |
336 | struct kthread *kthread = task_get_live_kthread(k); | |
337 | ||
338 | if (kthread) { | |
339 | clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags); | |
340 | /* | |
341 | * We clear the IS_PARKED bit here as we don't wait | |
342 | * until the task has left the park code. So if we'd | |
343 | * park before that happens we'd see the IS_PARKED bit | |
344 | * which might be about to be cleared. | |
345 | */ | |
346 | if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) { | |
347 | if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags)) | |
348 | __kthread_bind(k, kthread->cpu); | |
349 | wake_up_process(k); | |
350 | } | |
351 | } | |
352 | put_task_struct(k); | |
353 | } | |
354 | ||
355 | /** | |
356 | * kthread_park - park a thread created by kthread_create(). | |
357 | * @k: thread created by kthread_create(). | |
358 | * | |
359 | * Sets kthread_should_park() for @k to return true, wakes it, and | |
360 | * waits for it to return. This can also be called after kthread_create() | |
361 | * instead of calling wake_up_process(): the thread will park without | |
362 | * calling threadfn(). | |
363 | * | |
364 | * Returns 0 if the thread is parked, -ENOSYS if the thread exited. | |
365 | * If called by the kthread itself just the park bit is set. | |
366 | */ | |
367 | int kthread_park(struct task_struct *k) | |
368 | { | |
369 | struct kthread *kthread = task_get_live_kthread(k); | |
370 | int ret = -ENOSYS; | |
371 | ||
372 | if (kthread) { | |
373 | if (!test_bit(KTHREAD_IS_PARKED, &kthread->flags)) { | |
374 | set_bit(KTHREAD_SHOULD_PARK, &kthread->flags); | |
375 | if (k != current) { | |
376 | wake_up_process(k); | |
377 | wait_for_completion(&kthread->parked); | |
378 | } | |
379 | } | |
380 | ret = 0; | |
381 | } | |
382 | put_task_struct(k); | |
383 | return ret; | |
384 | } | |
385 | ||
9e37bd30 RD |
386 | /** |
387 | * kthread_stop - stop a thread created by kthread_create(). | |
388 | * @k: thread created by kthread_create(). | |
389 | * | |
390 | * Sets kthread_should_stop() for @k to return true, wakes it, and | |
9ae26027 ON |
391 | * waits for it to exit. This can also be called after kthread_create() |
392 | * instead of calling wake_up_process(): the thread will exit without | |
393 | * calling threadfn(). | |
394 | * | |
395 | * If threadfn() may call do_exit() itself, the caller must ensure | |
396 | * task_struct can't go away. | |
9e37bd30 RD |
397 | * |
398 | * Returns the result of threadfn(), or %-EINTR if wake_up_process() | |
399 | * was never called. | |
400 | */ | |
1da177e4 LT |
401 | int kthread_stop(struct task_struct *k) |
402 | { | |
2a1d4460 | 403 | struct kthread *kthread = task_get_live_kthread(k); |
1da177e4 LT |
404 | int ret; |
405 | ||
0a16b607 | 406 | trace_sched_kthread_stop(k); |
2a1d4460 TG |
407 | if (kthread) { |
408 | set_bit(KTHREAD_SHOULD_STOP, &kthread->flags); | |
409 | clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags); | |
63706172 ON |
410 | wake_up_process(k); |
411 | wait_for_completion(&kthread->exited); | |
412 | } | |
413 | ret = k->exit_code; | |
1da177e4 | 414 | |
1da177e4 | 415 | put_task_struct(k); |
0a16b607 MD |
416 | trace_sched_kthread_stop_ret(ret); |
417 | ||
1da177e4 LT |
418 | return ret; |
419 | } | |
52e92e57 | 420 | EXPORT_SYMBOL(kthread_stop); |
1da177e4 | 421 | |
e804a4a4 | 422 | int kthreadd(void *unused) |
1da177e4 | 423 | { |
73c27992 | 424 | struct task_struct *tsk = current; |
1da177e4 | 425 | |
e804a4a4 | 426 | /* Setup a clean context for our children to inherit. */ |
73c27992 | 427 | set_task_comm(tsk, "kthreadd"); |
10ab825b | 428 | ignore_signals(tsk); |
1a2142af | 429 | set_cpus_allowed_ptr(tsk, cpu_all_mask); |
5ab116c9 | 430 | set_mems_allowed(node_states[N_HIGH_MEMORY]); |
73c27992 | 431 | |
34b087e4 | 432 | current->flags |= PF_NOFREEZE; |
73c27992 EB |
433 | |
434 | for (;;) { | |
435 | set_current_state(TASK_INTERRUPTIBLE); | |
436 | if (list_empty(&kthread_create_list)) | |
437 | schedule(); | |
438 | __set_current_state(TASK_RUNNING); | |
439 | ||
440 | spin_lock(&kthread_create_lock); | |
441 | while (!list_empty(&kthread_create_list)) { | |
442 | struct kthread_create_info *create; | |
443 | ||
444 | create = list_entry(kthread_create_list.next, | |
445 | struct kthread_create_info, list); | |
446 | list_del_init(&create->list); | |
447 | spin_unlock(&kthread_create_lock); | |
448 | ||
449 | create_kthread(create); | |
450 | ||
451 | spin_lock(&kthread_create_lock); | |
452 | } | |
453 | spin_unlock(&kthread_create_lock); | |
454 | } | |
455 | ||
456 | return 0; | |
457 | } | |
b56c0d89 | 458 | |
4f32e9b1 YZ |
459 | void __init_kthread_worker(struct kthread_worker *worker, |
460 | const char *name, | |
461 | struct lock_class_key *key) | |
462 | { | |
463 | spin_lock_init(&worker->lock); | |
464 | lockdep_set_class_and_name(&worker->lock, key, name); | |
465 | INIT_LIST_HEAD(&worker->work_list); | |
466 | worker->task = NULL; | |
467 | } | |
468 | EXPORT_SYMBOL_GPL(__init_kthread_worker); | |
469 | ||
b56c0d89 TH |
470 | /** |
471 | * kthread_worker_fn - kthread function to process kthread_worker | |
472 | * @worker_ptr: pointer to initialized kthread_worker | |
473 | * | |
474 | * This function can be used as @threadfn to kthread_create() or | |
475 | * kthread_run() with @worker_ptr argument pointing to an initialized | |
476 | * kthread_worker. The started kthread will process work_list until | |
477 | * the it is stopped with kthread_stop(). A kthread can also call | |
478 | * this function directly after extra initialization. | |
479 | * | |
480 | * Different kthreads can be used for the same kthread_worker as long | |
481 | * as there's only one kthread attached to it at any given time. A | |
482 | * kthread_worker without an attached kthread simply collects queued | |
483 | * kthread_works. | |
484 | */ | |
485 | int kthread_worker_fn(void *worker_ptr) | |
486 | { | |
487 | struct kthread_worker *worker = worker_ptr; | |
488 | struct kthread_work *work; | |
489 | ||
490 | WARN_ON(worker->task); | |
491 | worker->task = current; | |
492 | repeat: | |
493 | set_current_state(TASK_INTERRUPTIBLE); /* mb paired w/ kthread_stop */ | |
494 | ||
495 | if (kthread_should_stop()) { | |
496 | __set_current_state(TASK_RUNNING); | |
497 | spin_lock_irq(&worker->lock); | |
498 | worker->task = NULL; | |
499 | spin_unlock_irq(&worker->lock); | |
500 | return 0; | |
501 | } | |
502 | ||
503 | work = NULL; | |
504 | spin_lock_irq(&worker->lock); | |
505 | if (!list_empty(&worker->work_list)) { | |
506 | work = list_first_entry(&worker->work_list, | |
507 | struct kthread_work, node); | |
508 | list_del_init(&work->node); | |
509 | } | |
46f3d976 | 510 | worker->current_work = work; |
b56c0d89 TH |
511 | spin_unlock_irq(&worker->lock); |
512 | ||
513 | if (work) { | |
514 | __set_current_state(TASK_RUNNING); | |
515 | work->func(work); | |
b56c0d89 TH |
516 | } else if (!freezing(current)) |
517 | schedule(); | |
518 | ||
519 | try_to_freeze(); | |
520 | goto repeat; | |
521 | } | |
522 | EXPORT_SYMBOL_GPL(kthread_worker_fn); | |
523 | ||
9a2e03d8 TH |
524 | /* insert @work before @pos in @worker */ |
525 | static void insert_kthread_work(struct kthread_worker *worker, | |
526 | struct kthread_work *work, | |
527 | struct list_head *pos) | |
528 | { | |
529 | lockdep_assert_held(&worker->lock); | |
530 | ||
531 | list_add_tail(&work->node, pos); | |
46f3d976 | 532 | work->worker = worker; |
9a2e03d8 TH |
533 | if (likely(worker->task)) |
534 | wake_up_process(worker->task); | |
535 | } | |
536 | ||
b56c0d89 TH |
537 | /** |
538 | * queue_kthread_work - queue a kthread_work | |
539 | * @worker: target kthread_worker | |
540 | * @work: kthread_work to queue | |
541 | * | |
542 | * Queue @work to work processor @task for async execution. @task | |
543 | * must have been created with kthread_worker_create(). Returns %true | |
544 | * if @work was successfully queued, %false if it was already pending. | |
545 | */ | |
546 | bool queue_kthread_work(struct kthread_worker *worker, | |
547 | struct kthread_work *work) | |
548 | { | |
549 | bool ret = false; | |
550 | unsigned long flags; | |
551 | ||
552 | spin_lock_irqsave(&worker->lock, flags); | |
553 | if (list_empty(&work->node)) { | |
9a2e03d8 | 554 | insert_kthread_work(worker, work, &worker->work_list); |
b56c0d89 TH |
555 | ret = true; |
556 | } | |
557 | spin_unlock_irqrestore(&worker->lock, flags); | |
558 | return ret; | |
559 | } | |
560 | EXPORT_SYMBOL_GPL(queue_kthread_work); | |
561 | ||
9a2e03d8 TH |
562 | struct kthread_flush_work { |
563 | struct kthread_work work; | |
564 | struct completion done; | |
565 | }; | |
566 | ||
567 | static void kthread_flush_work_fn(struct kthread_work *work) | |
568 | { | |
569 | struct kthread_flush_work *fwork = | |
570 | container_of(work, struct kthread_flush_work, work); | |
571 | complete(&fwork->done); | |
572 | } | |
573 | ||
b56c0d89 TH |
574 | /** |
575 | * flush_kthread_work - flush a kthread_work | |
576 | * @work: work to flush | |
577 | * | |
578 | * If @work is queued or executing, wait for it to finish execution. | |
579 | */ | |
580 | void flush_kthread_work(struct kthread_work *work) | |
581 | { | |
46f3d976 TH |
582 | struct kthread_flush_work fwork = { |
583 | KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn), | |
584 | COMPLETION_INITIALIZER_ONSTACK(fwork.done), | |
585 | }; | |
586 | struct kthread_worker *worker; | |
587 | bool noop = false; | |
588 | ||
589 | retry: | |
590 | worker = work->worker; | |
591 | if (!worker) | |
592 | return; | |
b56c0d89 | 593 | |
46f3d976 TH |
594 | spin_lock_irq(&worker->lock); |
595 | if (work->worker != worker) { | |
596 | spin_unlock_irq(&worker->lock); | |
597 | goto retry; | |
598 | } | |
b56c0d89 | 599 | |
46f3d976 TH |
600 | if (!list_empty(&work->node)) |
601 | insert_kthread_work(worker, &fwork.work, work->node.next); | |
602 | else if (worker->current_work == work) | |
603 | insert_kthread_work(worker, &fwork.work, worker->work_list.next); | |
604 | else | |
605 | noop = true; | |
b56c0d89 | 606 | |
46f3d976 | 607 | spin_unlock_irq(&worker->lock); |
b56c0d89 | 608 | |
46f3d976 TH |
609 | if (!noop) |
610 | wait_for_completion(&fwork.done); | |
b56c0d89 TH |
611 | } |
612 | EXPORT_SYMBOL_GPL(flush_kthread_work); | |
613 | ||
b56c0d89 TH |
614 | /** |
615 | * flush_kthread_worker - flush all current works on a kthread_worker | |
616 | * @worker: worker to flush | |
617 | * | |
618 | * Wait until all currently executing or pending works on @worker are | |
619 | * finished. | |
620 | */ | |
621 | void flush_kthread_worker(struct kthread_worker *worker) | |
622 | { | |
623 | struct kthread_flush_work fwork = { | |
624 | KTHREAD_WORK_INIT(fwork.work, kthread_flush_work_fn), | |
625 | COMPLETION_INITIALIZER_ONSTACK(fwork.done), | |
626 | }; | |
627 | ||
628 | queue_kthread_work(worker, &fwork.work); | |
629 | wait_for_completion(&fwork.done); | |
630 | } | |
631 | EXPORT_SYMBOL_GPL(flush_kthread_worker); |