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1 | /* | |
2 | * padata.c - generic interface to process data streams in parallel | |
3 | * | |
4 | * See Documentation/padata.txt for an api documentation. | |
5 | * | |
6 | * Copyright (C) 2008, 2009 secunet Security Networks AG | |
7 | * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify it | |
10 | * under the terms and conditions of the GNU General Public License, | |
11 | * version 2, as published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope it will be useful, but WITHOUT | |
14 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
16 | * more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License along with | |
19 | * this program; if not, write to the Free Software Foundation, Inc., | |
20 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
21 | */ | |
22 | ||
23 | #include <linux/export.h> | |
24 | #include <linux/cpumask.h> | |
25 | #include <linux/err.h> | |
26 | #include <linux/cpu.h> | |
27 | #include <linux/padata.h> | |
28 | #include <linux/mutex.h> | |
29 | #include <linux/sched.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/sysfs.h> | |
32 | #include <linux/rcupdate.h> | |
33 | #include <linux/module.h> | |
34 | ||
35 | #define MAX_OBJ_NUM 1000 | |
36 | ||
37 | static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index) | |
38 | { | |
39 | int cpu, target_cpu; | |
40 | ||
41 | target_cpu = cpumask_first(pd->cpumask.pcpu); | |
42 | for (cpu = 0; cpu < cpu_index; cpu++) | |
43 | target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu); | |
44 | ||
45 | return target_cpu; | |
46 | } | |
47 | ||
48 | static int padata_cpu_hash(struct parallel_data *pd) | |
49 | { | |
50 | unsigned int seq_nr; | |
51 | int cpu_index; | |
52 | ||
53 | /* | |
54 | * Hash the sequence numbers to the cpus by taking | |
55 | * seq_nr mod. number of cpus in use. | |
56 | */ | |
57 | ||
58 | seq_nr = atomic_inc_return(&pd->seq_nr); | |
59 | cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu); | |
60 | ||
61 | return padata_index_to_cpu(pd, cpu_index); | |
62 | } | |
63 | ||
64 | static void padata_parallel_worker(struct work_struct *parallel_work) | |
65 | { | |
66 | struct padata_parallel_queue *pqueue; | |
67 | LIST_HEAD(local_list); | |
68 | ||
69 | local_bh_disable(); | |
70 | pqueue = container_of(parallel_work, | |
71 | struct padata_parallel_queue, work); | |
72 | ||
73 | spin_lock(&pqueue->parallel.lock); | |
74 | list_replace_init(&pqueue->parallel.list, &local_list); | |
75 | spin_unlock(&pqueue->parallel.lock); | |
76 | ||
77 | while (!list_empty(&local_list)) { | |
78 | struct padata_priv *padata; | |
79 | ||
80 | padata = list_entry(local_list.next, | |
81 | struct padata_priv, list); | |
82 | ||
83 | list_del_init(&padata->list); | |
84 | ||
85 | padata->parallel(padata); | |
86 | } | |
87 | ||
88 | local_bh_enable(); | |
89 | } | |
90 | ||
91 | /** | |
92 | * padata_do_parallel - padata parallelization function | |
93 | * | |
94 | * @pinst: padata instance | |
95 | * @padata: object to be parallelized | |
96 | * @cb_cpu: cpu the serialization callback function will run on, | |
97 | * must be in the serial cpumask of padata(i.e. cpumask.cbcpu). | |
98 | * | |
99 | * The parallelization callback function will run with BHs off. | |
100 | * Note: Every object which is parallelized by padata_do_parallel | |
101 | * must be seen by padata_do_serial. | |
102 | */ | |
103 | int padata_do_parallel(struct padata_instance *pinst, | |
104 | struct padata_priv *padata, int cb_cpu) | |
105 | { | |
106 | int target_cpu, err; | |
107 | struct padata_parallel_queue *queue; | |
108 | struct parallel_data *pd; | |
109 | ||
110 | rcu_read_lock_bh(); | |
111 | ||
112 | pd = rcu_dereference_bh(pinst->pd); | |
113 | ||
114 | err = -EINVAL; | |
115 | if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID) | |
116 | goto out; | |
117 | ||
118 | if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu)) | |
119 | goto out; | |
120 | ||
121 | err = -EBUSY; | |
122 | if ((pinst->flags & PADATA_RESET)) | |
123 | goto out; | |
124 | ||
125 | if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM) | |
126 | goto out; | |
127 | ||
128 | err = 0; | |
129 | atomic_inc(&pd->refcnt); | |
130 | padata->pd = pd; | |
131 | padata->cb_cpu = cb_cpu; | |
132 | ||
133 | target_cpu = padata_cpu_hash(pd); | |
134 | queue = per_cpu_ptr(pd->pqueue, target_cpu); | |
135 | ||
136 | spin_lock(&queue->parallel.lock); | |
137 | list_add_tail(&padata->list, &queue->parallel.list); | |
138 | spin_unlock(&queue->parallel.lock); | |
139 | ||
140 | queue_work_on(target_cpu, pinst->wq, &queue->work); | |
141 | ||
142 | out: | |
143 | rcu_read_unlock_bh(); | |
144 | ||
145 | return err; | |
146 | } | |
147 | EXPORT_SYMBOL(padata_do_parallel); | |
148 | ||
149 | /* | |
150 | * padata_get_next - Get the next object that needs serialization. | |
151 | * | |
152 | * Return values are: | |
153 | * | |
154 | * A pointer to the control struct of the next object that needs | |
155 | * serialization, if present in one of the percpu reorder queues. | |
156 | * | |
157 | * -EINPROGRESS, if the next object that needs serialization will | |
158 | * be parallel processed by another cpu and is not yet present in | |
159 | * the cpu's reorder queue. | |
160 | * | |
161 | * -ENODATA, if this cpu has to do the parallel processing for | |
162 | * the next object. | |
163 | */ | |
164 | static struct padata_priv *padata_get_next(struct parallel_data *pd) | |
165 | { | |
166 | int cpu, num_cpus; | |
167 | unsigned int next_nr, next_index; | |
168 | struct padata_parallel_queue *next_queue; | |
169 | struct padata_priv *padata; | |
170 | struct padata_list *reorder; | |
171 | ||
172 | num_cpus = cpumask_weight(pd->cpumask.pcpu); | |
173 | ||
174 | /* | |
175 | * Calculate the percpu reorder queue and the sequence | |
176 | * number of the next object. | |
177 | */ | |
178 | next_nr = pd->processed; | |
179 | next_index = next_nr % num_cpus; | |
180 | cpu = padata_index_to_cpu(pd, next_index); | |
181 | next_queue = per_cpu_ptr(pd->pqueue, cpu); | |
182 | ||
183 | reorder = &next_queue->reorder; | |
184 | ||
185 | spin_lock(&reorder->lock); | |
186 | if (!list_empty(&reorder->list)) { | |
187 | padata = list_entry(reorder->list.next, | |
188 | struct padata_priv, list); | |
189 | ||
190 | list_del_init(&padata->list); | |
191 | atomic_dec(&pd->reorder_objects); | |
192 | ||
193 | pd->processed++; | |
194 | ||
195 | spin_unlock(&reorder->lock); | |
196 | goto out; | |
197 | } | |
198 | spin_unlock(&reorder->lock); | |
199 | ||
200 | if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) { | |
201 | padata = ERR_PTR(-ENODATA); | |
202 | goto out; | |
203 | } | |
204 | ||
205 | padata = ERR_PTR(-EINPROGRESS); | |
206 | out: | |
207 | return padata; | |
208 | } | |
209 | ||
210 | static void padata_reorder(struct parallel_data *pd) | |
211 | { | |
212 | int cb_cpu; | |
213 | struct padata_priv *padata; | |
214 | struct padata_serial_queue *squeue; | |
215 | struct padata_instance *pinst = pd->pinst; | |
216 | ||
217 | /* | |
218 | * We need to ensure that only one cpu can work on dequeueing of | |
219 | * the reorder queue the time. Calculating in which percpu reorder | |
220 | * queue the next object will arrive takes some time. A spinlock | |
221 | * would be highly contended. Also it is not clear in which order | |
222 | * the objects arrive to the reorder queues. So a cpu could wait to | |
223 | * get the lock just to notice that there is nothing to do at the | |
224 | * moment. Therefore we use a trylock and let the holder of the lock | |
225 | * care for all the objects enqueued during the holdtime of the lock. | |
226 | */ | |
227 | if (!spin_trylock_bh(&pd->lock)) | |
228 | return; | |
229 | ||
230 | while (1) { | |
231 | padata = padata_get_next(pd); | |
232 | ||
233 | /* | |
234 | * If the next object that needs serialization is parallel | |
235 | * processed by another cpu and is still on it's way to the | |
236 | * cpu's reorder queue, nothing to do for now. | |
237 | */ | |
238 | if (PTR_ERR(padata) == -EINPROGRESS) | |
239 | break; | |
240 | ||
241 | /* | |
242 | * This cpu has to do the parallel processing of the next | |
243 | * object. It's waiting in the cpu's parallelization queue, | |
244 | * so exit immediately. | |
245 | */ | |
246 | if (PTR_ERR(padata) == -ENODATA) { | |
247 | del_timer(&pd->timer); | |
248 | spin_unlock_bh(&pd->lock); | |
249 | return; | |
250 | } | |
251 | ||
252 | cb_cpu = padata->cb_cpu; | |
253 | squeue = per_cpu_ptr(pd->squeue, cb_cpu); | |
254 | ||
255 | spin_lock(&squeue->serial.lock); | |
256 | list_add_tail(&padata->list, &squeue->serial.list); | |
257 | spin_unlock(&squeue->serial.lock); | |
258 | ||
259 | queue_work_on(cb_cpu, pinst->wq, &squeue->work); | |
260 | } | |
261 | ||
262 | spin_unlock_bh(&pd->lock); | |
263 | ||
264 | /* | |
265 | * The next object that needs serialization might have arrived to | |
266 | * the reorder queues in the meantime, we will be called again | |
267 | * from the timer function if no one else cares for it. | |
268 | */ | |
269 | if (atomic_read(&pd->reorder_objects) | |
270 | && !(pinst->flags & PADATA_RESET)) | |
271 | mod_timer(&pd->timer, jiffies + HZ); | |
272 | else | |
273 | del_timer(&pd->timer); | |
274 | ||
275 | return; | |
276 | } | |
277 | ||
278 | static void padata_reorder_timer(unsigned long arg) | |
279 | { | |
280 | struct parallel_data *pd = (struct parallel_data *)arg; | |
281 | ||
282 | padata_reorder(pd); | |
283 | } | |
284 | ||
285 | static void padata_serial_worker(struct work_struct *serial_work) | |
286 | { | |
287 | struct padata_serial_queue *squeue; | |
288 | struct parallel_data *pd; | |
289 | LIST_HEAD(local_list); | |
290 | ||
291 | local_bh_disable(); | |
292 | squeue = container_of(serial_work, struct padata_serial_queue, work); | |
293 | pd = squeue->pd; | |
294 | ||
295 | spin_lock(&squeue->serial.lock); | |
296 | list_replace_init(&squeue->serial.list, &local_list); | |
297 | spin_unlock(&squeue->serial.lock); | |
298 | ||
299 | while (!list_empty(&local_list)) { | |
300 | struct padata_priv *padata; | |
301 | ||
302 | padata = list_entry(local_list.next, | |
303 | struct padata_priv, list); | |
304 | ||
305 | list_del_init(&padata->list); | |
306 | ||
307 | padata->serial(padata); | |
308 | atomic_dec(&pd->refcnt); | |
309 | } | |
310 | local_bh_enable(); | |
311 | } | |
312 | ||
313 | /** | |
314 | * padata_do_serial - padata serialization function | |
315 | * | |
316 | * @padata: object to be serialized. | |
317 | * | |
318 | * padata_do_serial must be called for every parallelized object. | |
319 | * The serialization callback function will run with BHs off. | |
320 | */ | |
321 | void padata_do_serial(struct padata_priv *padata) | |
322 | { | |
323 | int cpu; | |
324 | struct padata_parallel_queue *pqueue; | |
325 | struct parallel_data *pd; | |
326 | ||
327 | pd = padata->pd; | |
328 | ||
329 | cpu = get_cpu(); | |
330 | pqueue = per_cpu_ptr(pd->pqueue, cpu); | |
331 | ||
332 | spin_lock(&pqueue->reorder.lock); | |
333 | atomic_inc(&pd->reorder_objects); | |
334 | list_add_tail(&padata->list, &pqueue->reorder.list); | |
335 | spin_unlock(&pqueue->reorder.lock); | |
336 | ||
337 | put_cpu(); | |
338 | ||
339 | padata_reorder(pd); | |
340 | } | |
341 | EXPORT_SYMBOL(padata_do_serial); | |
342 | ||
343 | static int padata_setup_cpumasks(struct parallel_data *pd, | |
344 | const struct cpumask *pcpumask, | |
345 | const struct cpumask *cbcpumask) | |
346 | { | |
347 | if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL)) | |
348 | return -ENOMEM; | |
349 | ||
350 | cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask); | |
351 | if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) { | |
352 | free_cpumask_var(pd->cpumask.pcpu); | |
353 | return -ENOMEM; | |
354 | } | |
355 | ||
356 | cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask); | |
357 | return 0; | |
358 | } | |
359 | ||
360 | static void __padata_list_init(struct padata_list *pd_list) | |
361 | { | |
362 | INIT_LIST_HEAD(&pd_list->list); | |
363 | spin_lock_init(&pd_list->lock); | |
364 | } | |
365 | ||
366 | /* Initialize all percpu queues used by serial workers */ | |
367 | static void padata_init_squeues(struct parallel_data *pd) | |
368 | { | |
369 | int cpu; | |
370 | struct padata_serial_queue *squeue; | |
371 | ||
372 | for_each_cpu(cpu, pd->cpumask.cbcpu) { | |
373 | squeue = per_cpu_ptr(pd->squeue, cpu); | |
374 | squeue->pd = pd; | |
375 | __padata_list_init(&squeue->serial); | |
376 | INIT_WORK(&squeue->work, padata_serial_worker); | |
377 | } | |
378 | } | |
379 | ||
380 | /* Initialize all percpu queues used by parallel workers */ | |
381 | static void padata_init_pqueues(struct parallel_data *pd) | |
382 | { | |
383 | int cpu_index, cpu; | |
384 | struct padata_parallel_queue *pqueue; | |
385 | ||
386 | cpu_index = 0; | |
387 | for_each_cpu(cpu, pd->cpumask.pcpu) { | |
388 | pqueue = per_cpu_ptr(pd->pqueue, cpu); | |
389 | pqueue->pd = pd; | |
390 | pqueue->cpu_index = cpu_index; | |
391 | cpu_index++; | |
392 | ||
393 | __padata_list_init(&pqueue->reorder); | |
394 | __padata_list_init(&pqueue->parallel); | |
395 | INIT_WORK(&pqueue->work, padata_parallel_worker); | |
396 | atomic_set(&pqueue->num_obj, 0); | |
397 | } | |
398 | } | |
399 | ||
400 | /* Allocate and initialize the internal cpumask dependend resources. */ | |
401 | static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst, | |
402 | const struct cpumask *pcpumask, | |
403 | const struct cpumask *cbcpumask) | |
404 | { | |
405 | struct parallel_data *pd; | |
406 | ||
407 | pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL); | |
408 | if (!pd) | |
409 | goto err; | |
410 | ||
411 | pd->pqueue = alloc_percpu(struct padata_parallel_queue); | |
412 | if (!pd->pqueue) | |
413 | goto err_free_pd; | |
414 | ||
415 | pd->squeue = alloc_percpu(struct padata_serial_queue); | |
416 | if (!pd->squeue) | |
417 | goto err_free_pqueue; | |
418 | if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0) | |
419 | goto err_free_squeue; | |
420 | ||
421 | padata_init_pqueues(pd); | |
422 | padata_init_squeues(pd); | |
423 | setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd); | |
424 | atomic_set(&pd->seq_nr, -1); | |
425 | atomic_set(&pd->reorder_objects, 0); | |
426 | atomic_set(&pd->refcnt, 0); | |
427 | pd->pinst = pinst; | |
428 | spin_lock_init(&pd->lock); | |
429 | ||
430 | return pd; | |
431 | ||
432 | err_free_squeue: | |
433 | free_percpu(pd->squeue); | |
434 | err_free_pqueue: | |
435 | free_percpu(pd->pqueue); | |
436 | err_free_pd: | |
437 | kfree(pd); | |
438 | err: | |
439 | return NULL; | |
440 | } | |
441 | ||
442 | static void padata_free_pd(struct parallel_data *pd) | |
443 | { | |
444 | free_cpumask_var(pd->cpumask.pcpu); | |
445 | free_cpumask_var(pd->cpumask.cbcpu); | |
446 | free_percpu(pd->pqueue); | |
447 | free_percpu(pd->squeue); | |
448 | kfree(pd); | |
449 | } | |
450 | ||
451 | /* Flush all objects out of the padata queues. */ | |
452 | static void padata_flush_queues(struct parallel_data *pd) | |
453 | { | |
454 | int cpu; | |
455 | struct padata_parallel_queue *pqueue; | |
456 | struct padata_serial_queue *squeue; | |
457 | ||
458 | for_each_cpu(cpu, pd->cpumask.pcpu) { | |
459 | pqueue = per_cpu_ptr(pd->pqueue, cpu); | |
460 | flush_work(&pqueue->work); | |
461 | } | |
462 | ||
463 | del_timer_sync(&pd->timer); | |
464 | ||
465 | if (atomic_read(&pd->reorder_objects)) | |
466 | padata_reorder(pd); | |
467 | ||
468 | for_each_cpu(cpu, pd->cpumask.cbcpu) { | |
469 | squeue = per_cpu_ptr(pd->squeue, cpu); | |
470 | flush_work(&squeue->work); | |
471 | } | |
472 | ||
473 | BUG_ON(atomic_read(&pd->refcnt) != 0); | |
474 | } | |
475 | ||
476 | static void __padata_start(struct padata_instance *pinst) | |
477 | { | |
478 | pinst->flags |= PADATA_INIT; | |
479 | } | |
480 | ||
481 | static void __padata_stop(struct padata_instance *pinst) | |
482 | { | |
483 | if (!(pinst->flags & PADATA_INIT)) | |
484 | return; | |
485 | ||
486 | pinst->flags &= ~PADATA_INIT; | |
487 | ||
488 | synchronize_rcu(); | |
489 | ||
490 | get_online_cpus(); | |
491 | padata_flush_queues(pinst->pd); | |
492 | put_online_cpus(); | |
493 | } | |
494 | ||
495 | /* Replace the internal control structure with a new one. */ | |
496 | static void padata_replace(struct padata_instance *pinst, | |
497 | struct parallel_data *pd_new) | |
498 | { | |
499 | struct parallel_data *pd_old = pinst->pd; | |
500 | int notification_mask = 0; | |
501 | ||
502 | pinst->flags |= PADATA_RESET; | |
503 | ||
504 | rcu_assign_pointer(pinst->pd, pd_new); | |
505 | ||
506 | synchronize_rcu(); | |
507 | ||
508 | if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu)) | |
509 | notification_mask |= PADATA_CPU_PARALLEL; | |
510 | if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu)) | |
511 | notification_mask |= PADATA_CPU_SERIAL; | |
512 | ||
513 | padata_flush_queues(pd_old); | |
514 | padata_free_pd(pd_old); | |
515 | ||
516 | if (notification_mask) | |
517 | blocking_notifier_call_chain(&pinst->cpumask_change_notifier, | |
518 | notification_mask, | |
519 | &pd_new->cpumask); | |
520 | ||
521 | pinst->flags &= ~PADATA_RESET; | |
522 | } | |
523 | ||
524 | /** | |
525 | * padata_register_cpumask_notifier - Registers a notifier that will be called | |
526 | * if either pcpu or cbcpu or both cpumasks change. | |
527 | * | |
528 | * @pinst: A poineter to padata instance | |
529 | * @nblock: A pointer to notifier block. | |
530 | */ | |
531 | int padata_register_cpumask_notifier(struct padata_instance *pinst, | |
532 | struct notifier_block *nblock) | |
533 | { | |
534 | return blocking_notifier_chain_register(&pinst->cpumask_change_notifier, | |
535 | nblock); | |
536 | } | |
537 | EXPORT_SYMBOL(padata_register_cpumask_notifier); | |
538 | ||
539 | /** | |
540 | * padata_unregister_cpumask_notifier - Unregisters cpumask notifier | |
541 | * registered earlier using padata_register_cpumask_notifier | |
542 | * | |
543 | * @pinst: A pointer to data instance. | |
544 | * @nlock: A pointer to notifier block. | |
545 | */ | |
546 | int padata_unregister_cpumask_notifier(struct padata_instance *pinst, | |
547 | struct notifier_block *nblock) | |
548 | { | |
549 | return blocking_notifier_chain_unregister( | |
550 | &pinst->cpumask_change_notifier, | |
551 | nblock); | |
552 | } | |
553 | EXPORT_SYMBOL(padata_unregister_cpumask_notifier); | |
554 | ||
555 | ||
556 | /* If cpumask contains no active cpu, we mark the instance as invalid. */ | |
557 | static bool padata_validate_cpumask(struct padata_instance *pinst, | |
558 | const struct cpumask *cpumask) | |
559 | { | |
560 | if (!cpumask_intersects(cpumask, cpu_online_mask)) { | |
561 | pinst->flags |= PADATA_INVALID; | |
562 | return false; | |
563 | } | |
564 | ||
565 | pinst->flags &= ~PADATA_INVALID; | |
566 | return true; | |
567 | } | |
568 | ||
569 | static int __padata_set_cpumasks(struct padata_instance *pinst, | |
570 | cpumask_var_t pcpumask, | |
571 | cpumask_var_t cbcpumask) | |
572 | { | |
573 | int valid; | |
574 | struct parallel_data *pd; | |
575 | ||
576 | valid = padata_validate_cpumask(pinst, pcpumask); | |
577 | if (!valid) { | |
578 | __padata_stop(pinst); | |
579 | goto out_replace; | |
580 | } | |
581 | ||
582 | valid = padata_validate_cpumask(pinst, cbcpumask); | |
583 | if (!valid) | |
584 | __padata_stop(pinst); | |
585 | ||
586 | out_replace: | |
587 | pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); | |
588 | if (!pd) | |
589 | return -ENOMEM; | |
590 | ||
591 | cpumask_copy(pinst->cpumask.pcpu, pcpumask); | |
592 | cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); | |
593 | ||
594 | padata_replace(pinst, pd); | |
595 | ||
596 | if (valid) | |
597 | __padata_start(pinst); | |
598 | ||
599 | return 0; | |
600 | } | |
601 | ||
602 | /** | |
603 | * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value | |
604 | * equivalent to @cpumask. | |
605 | * | |
606 | * @pinst: padata instance | |
607 | * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding | |
608 | * to parallel and serial cpumasks respectively. | |
609 | * @cpumask: the cpumask to use | |
610 | */ | |
611 | int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, | |
612 | cpumask_var_t cpumask) | |
613 | { | |
614 | struct cpumask *serial_mask, *parallel_mask; | |
615 | int err = -EINVAL; | |
616 | ||
617 | mutex_lock(&pinst->lock); | |
618 | get_online_cpus(); | |
619 | ||
620 | switch (cpumask_type) { | |
621 | case PADATA_CPU_PARALLEL: | |
622 | serial_mask = pinst->cpumask.cbcpu; | |
623 | parallel_mask = cpumask; | |
624 | break; | |
625 | case PADATA_CPU_SERIAL: | |
626 | parallel_mask = pinst->cpumask.pcpu; | |
627 | serial_mask = cpumask; | |
628 | break; | |
629 | default: | |
630 | goto out; | |
631 | } | |
632 | ||
633 | err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask); | |
634 | ||
635 | out: | |
636 | put_online_cpus(); | |
637 | mutex_unlock(&pinst->lock); | |
638 | ||
639 | return err; | |
640 | } | |
641 | EXPORT_SYMBOL(padata_set_cpumask); | |
642 | ||
643 | /** | |
644 | * padata_start - start the parallel processing | |
645 | * | |
646 | * @pinst: padata instance to start | |
647 | */ | |
648 | int padata_start(struct padata_instance *pinst) | |
649 | { | |
650 | int err = 0; | |
651 | ||
652 | mutex_lock(&pinst->lock); | |
653 | ||
654 | if (pinst->flags & PADATA_INVALID) | |
655 | err = -EINVAL; | |
656 | ||
657 | __padata_start(pinst); | |
658 | ||
659 | mutex_unlock(&pinst->lock); | |
660 | ||
661 | return err; | |
662 | } | |
663 | EXPORT_SYMBOL(padata_start); | |
664 | ||
665 | /** | |
666 | * padata_stop - stop the parallel processing | |
667 | * | |
668 | * @pinst: padata instance to stop | |
669 | */ | |
670 | void padata_stop(struct padata_instance *pinst) | |
671 | { | |
672 | mutex_lock(&pinst->lock); | |
673 | __padata_stop(pinst); | |
674 | mutex_unlock(&pinst->lock); | |
675 | } | |
676 | EXPORT_SYMBOL(padata_stop); | |
677 | ||
678 | #ifdef CONFIG_HOTPLUG_CPU | |
679 | ||
680 | static int __padata_add_cpu(struct padata_instance *pinst, int cpu) | |
681 | { | |
682 | struct parallel_data *pd; | |
683 | ||
684 | if (cpumask_test_cpu(cpu, cpu_online_mask)) { | |
685 | pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, | |
686 | pinst->cpumask.cbcpu); | |
687 | if (!pd) | |
688 | return -ENOMEM; | |
689 | ||
690 | padata_replace(pinst, pd); | |
691 | ||
692 | if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) && | |
693 | padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) | |
694 | __padata_start(pinst); | |
695 | } | |
696 | ||
697 | return 0; | |
698 | } | |
699 | ||
700 | static int __padata_remove_cpu(struct padata_instance *pinst, int cpu) | |
701 | { | |
702 | struct parallel_data *pd = NULL; | |
703 | ||
704 | if (cpumask_test_cpu(cpu, cpu_online_mask)) { | |
705 | ||
706 | if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) || | |
707 | !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) | |
708 | __padata_stop(pinst); | |
709 | ||
710 | pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, | |
711 | pinst->cpumask.cbcpu); | |
712 | if (!pd) | |
713 | return -ENOMEM; | |
714 | ||
715 | padata_replace(pinst, pd); | |
716 | ||
717 | cpumask_clear_cpu(cpu, pd->cpumask.cbcpu); | |
718 | cpumask_clear_cpu(cpu, pd->cpumask.pcpu); | |
719 | } | |
720 | ||
721 | return 0; | |
722 | } | |
723 | ||
724 | /** | |
725 | * padata_remove_cpu - remove a cpu from the one or both(serial and parallel) | |
726 | * padata cpumasks. | |
727 | * | |
728 | * @pinst: padata instance | |
729 | * @cpu: cpu to remove | |
730 | * @mask: bitmask specifying from which cpumask @cpu should be removed | |
731 | * The @mask may be any combination of the following flags: | |
732 | * PADATA_CPU_SERIAL - serial cpumask | |
733 | * PADATA_CPU_PARALLEL - parallel cpumask | |
734 | */ | |
735 | int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask) | |
736 | { | |
737 | int err; | |
738 | ||
739 | if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL))) | |
740 | return -EINVAL; | |
741 | ||
742 | mutex_lock(&pinst->lock); | |
743 | ||
744 | get_online_cpus(); | |
745 | if (mask & PADATA_CPU_SERIAL) | |
746 | cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu); | |
747 | if (mask & PADATA_CPU_PARALLEL) | |
748 | cpumask_clear_cpu(cpu, pinst->cpumask.pcpu); | |
749 | ||
750 | err = __padata_remove_cpu(pinst, cpu); | |
751 | put_online_cpus(); | |
752 | ||
753 | mutex_unlock(&pinst->lock); | |
754 | ||
755 | return err; | |
756 | } | |
757 | EXPORT_SYMBOL(padata_remove_cpu); | |
758 | ||
759 | static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu) | |
760 | { | |
761 | return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) || | |
762 | cpumask_test_cpu(cpu, pinst->cpumask.cbcpu); | |
763 | } | |
764 | ||
765 | static int padata_cpu_online(unsigned int cpu, struct hlist_node *node) | |
766 | { | |
767 | struct padata_instance *pinst; | |
768 | int ret; | |
769 | ||
770 | pinst = hlist_entry_safe(node, struct padata_instance, node); | |
771 | if (!pinst_has_cpu(pinst, cpu)) | |
772 | return 0; | |
773 | ||
774 | mutex_lock(&pinst->lock); | |
775 | ret = __padata_add_cpu(pinst, cpu); | |
776 | mutex_unlock(&pinst->lock); | |
777 | return ret; | |
778 | } | |
779 | ||
780 | static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node) | |
781 | { | |
782 | struct padata_instance *pinst; | |
783 | int ret; | |
784 | ||
785 | pinst = hlist_entry_safe(node, struct padata_instance, node); | |
786 | if (!pinst_has_cpu(pinst, cpu)) | |
787 | return 0; | |
788 | ||
789 | mutex_lock(&pinst->lock); | |
790 | ret = __padata_remove_cpu(pinst, cpu); | |
791 | mutex_unlock(&pinst->lock); | |
792 | return ret; | |
793 | } | |
794 | ||
795 | static enum cpuhp_state hp_online; | |
796 | #endif | |
797 | ||
798 | static void __padata_free(struct padata_instance *pinst) | |
799 | { | |
800 | #ifdef CONFIG_HOTPLUG_CPU | |
801 | cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node); | |
802 | #endif | |
803 | ||
804 | padata_stop(pinst); | |
805 | padata_free_pd(pinst->pd); | |
806 | free_cpumask_var(pinst->cpumask.pcpu); | |
807 | free_cpumask_var(pinst->cpumask.cbcpu); | |
808 | kfree(pinst); | |
809 | } | |
810 | ||
811 | #define kobj2pinst(_kobj) \ | |
812 | container_of(_kobj, struct padata_instance, kobj) | |
813 | #define attr2pentry(_attr) \ | |
814 | container_of(_attr, struct padata_sysfs_entry, attr) | |
815 | ||
816 | static void padata_sysfs_release(struct kobject *kobj) | |
817 | { | |
818 | struct padata_instance *pinst = kobj2pinst(kobj); | |
819 | __padata_free(pinst); | |
820 | } | |
821 | ||
822 | struct padata_sysfs_entry { | |
823 | struct attribute attr; | |
824 | ssize_t (*show)(struct padata_instance *, struct attribute *, char *); | |
825 | ssize_t (*store)(struct padata_instance *, struct attribute *, | |
826 | const char *, size_t); | |
827 | }; | |
828 | ||
829 | static ssize_t show_cpumask(struct padata_instance *pinst, | |
830 | struct attribute *attr, char *buf) | |
831 | { | |
832 | struct cpumask *cpumask; | |
833 | ssize_t len; | |
834 | ||
835 | mutex_lock(&pinst->lock); | |
836 | if (!strcmp(attr->name, "serial_cpumask")) | |
837 | cpumask = pinst->cpumask.cbcpu; | |
838 | else | |
839 | cpumask = pinst->cpumask.pcpu; | |
840 | ||
841 | len = snprintf(buf, PAGE_SIZE, "%*pb\n", | |
842 | nr_cpu_ids, cpumask_bits(cpumask)); | |
843 | mutex_unlock(&pinst->lock); | |
844 | return len < PAGE_SIZE ? len : -EINVAL; | |
845 | } | |
846 | ||
847 | static ssize_t store_cpumask(struct padata_instance *pinst, | |
848 | struct attribute *attr, | |
849 | const char *buf, size_t count) | |
850 | { | |
851 | cpumask_var_t new_cpumask; | |
852 | ssize_t ret; | |
853 | int mask_type; | |
854 | ||
855 | if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL)) | |
856 | return -ENOMEM; | |
857 | ||
858 | ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask), | |
859 | nr_cpumask_bits); | |
860 | if (ret < 0) | |
861 | goto out; | |
862 | ||
863 | mask_type = !strcmp(attr->name, "serial_cpumask") ? | |
864 | PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL; | |
865 | ret = padata_set_cpumask(pinst, mask_type, new_cpumask); | |
866 | if (!ret) | |
867 | ret = count; | |
868 | ||
869 | out: | |
870 | free_cpumask_var(new_cpumask); | |
871 | return ret; | |
872 | } | |
873 | ||
874 | #define PADATA_ATTR_RW(_name, _show_name, _store_name) \ | |
875 | static struct padata_sysfs_entry _name##_attr = \ | |
876 | __ATTR(_name, 0644, _show_name, _store_name) | |
877 | #define PADATA_ATTR_RO(_name, _show_name) \ | |
878 | static struct padata_sysfs_entry _name##_attr = \ | |
879 | __ATTR(_name, 0400, _show_name, NULL) | |
880 | ||
881 | PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask); | |
882 | PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask); | |
883 | ||
884 | /* | |
885 | * Padata sysfs provides the following objects: | |
886 | * serial_cpumask [RW] - cpumask for serial workers | |
887 | * parallel_cpumask [RW] - cpumask for parallel workers | |
888 | */ | |
889 | static struct attribute *padata_default_attrs[] = { | |
890 | &serial_cpumask_attr.attr, | |
891 | ¶llel_cpumask_attr.attr, | |
892 | NULL, | |
893 | }; | |
894 | ||
895 | static ssize_t padata_sysfs_show(struct kobject *kobj, | |
896 | struct attribute *attr, char *buf) | |
897 | { | |
898 | struct padata_instance *pinst; | |
899 | struct padata_sysfs_entry *pentry; | |
900 | ssize_t ret = -EIO; | |
901 | ||
902 | pinst = kobj2pinst(kobj); | |
903 | pentry = attr2pentry(attr); | |
904 | if (pentry->show) | |
905 | ret = pentry->show(pinst, attr, buf); | |
906 | ||
907 | return ret; | |
908 | } | |
909 | ||
910 | static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr, | |
911 | const char *buf, size_t count) | |
912 | { | |
913 | struct padata_instance *pinst; | |
914 | struct padata_sysfs_entry *pentry; | |
915 | ssize_t ret = -EIO; | |
916 | ||
917 | pinst = kobj2pinst(kobj); | |
918 | pentry = attr2pentry(attr); | |
919 | if (pentry->show) | |
920 | ret = pentry->store(pinst, attr, buf, count); | |
921 | ||
922 | return ret; | |
923 | } | |
924 | ||
925 | static const struct sysfs_ops padata_sysfs_ops = { | |
926 | .show = padata_sysfs_show, | |
927 | .store = padata_sysfs_store, | |
928 | }; | |
929 | ||
930 | static struct kobj_type padata_attr_type = { | |
931 | .sysfs_ops = &padata_sysfs_ops, | |
932 | .default_attrs = padata_default_attrs, | |
933 | .release = padata_sysfs_release, | |
934 | }; | |
935 | ||
936 | /** | |
937 | * padata_alloc - allocate and initialize a padata instance and specify | |
938 | * cpumasks for serial and parallel workers. | |
939 | * | |
940 | * @wq: workqueue to use for the allocated padata instance | |
941 | * @pcpumask: cpumask that will be used for padata parallelization | |
942 | * @cbcpumask: cpumask that will be used for padata serialization | |
943 | * | |
944 | * Must be called from a cpus_read_lock() protected region | |
945 | */ | |
946 | static struct padata_instance *padata_alloc(struct workqueue_struct *wq, | |
947 | const struct cpumask *pcpumask, | |
948 | const struct cpumask *cbcpumask) | |
949 | { | |
950 | struct padata_instance *pinst; | |
951 | struct parallel_data *pd = NULL; | |
952 | ||
953 | pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL); | |
954 | if (!pinst) | |
955 | goto err; | |
956 | ||
957 | if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL)) | |
958 | goto err_free_inst; | |
959 | if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) { | |
960 | free_cpumask_var(pinst->cpumask.pcpu); | |
961 | goto err_free_inst; | |
962 | } | |
963 | if (!padata_validate_cpumask(pinst, pcpumask) || | |
964 | !padata_validate_cpumask(pinst, cbcpumask)) | |
965 | goto err_free_masks; | |
966 | ||
967 | pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); | |
968 | if (!pd) | |
969 | goto err_free_masks; | |
970 | ||
971 | rcu_assign_pointer(pinst->pd, pd); | |
972 | ||
973 | pinst->wq = wq; | |
974 | ||
975 | cpumask_copy(pinst->cpumask.pcpu, pcpumask); | |
976 | cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); | |
977 | ||
978 | pinst->flags = 0; | |
979 | ||
980 | BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier); | |
981 | kobject_init(&pinst->kobj, &padata_attr_type); | |
982 | mutex_init(&pinst->lock); | |
983 | ||
984 | #ifdef CONFIG_HOTPLUG_CPU | |
985 | cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node); | |
986 | #endif | |
987 | return pinst; | |
988 | ||
989 | err_free_masks: | |
990 | free_cpumask_var(pinst->cpumask.pcpu); | |
991 | free_cpumask_var(pinst->cpumask.cbcpu); | |
992 | err_free_inst: | |
993 | kfree(pinst); | |
994 | err: | |
995 | return NULL; | |
996 | } | |
997 | ||
998 | /** | |
999 | * padata_alloc_possible - Allocate and initialize padata instance. | |
1000 | * Use the cpu_possible_mask for serial and | |
1001 | * parallel workers. | |
1002 | * | |
1003 | * @wq: workqueue to use for the allocated padata instance | |
1004 | * | |
1005 | * Must be called from a cpus_read_lock() protected region | |
1006 | */ | |
1007 | struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq) | |
1008 | { | |
1009 | lockdep_assert_cpus_held(); | |
1010 | return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask); | |
1011 | } | |
1012 | EXPORT_SYMBOL(padata_alloc_possible); | |
1013 | ||
1014 | /** | |
1015 | * padata_free - free a padata instance | |
1016 | * | |
1017 | * @padata_inst: padata instance to free | |
1018 | */ | |
1019 | void padata_free(struct padata_instance *pinst) | |
1020 | { | |
1021 | kobject_put(&pinst->kobj); | |
1022 | } | |
1023 | EXPORT_SYMBOL(padata_free); | |
1024 | ||
1025 | #ifdef CONFIG_HOTPLUG_CPU | |
1026 | ||
1027 | static __init int padata_driver_init(void) | |
1028 | { | |
1029 | int ret; | |
1030 | ||
1031 | ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online", | |
1032 | padata_cpu_online, | |
1033 | padata_cpu_prep_down); | |
1034 | if (ret < 0) | |
1035 | return ret; | |
1036 | hp_online = ret; | |
1037 | return 0; | |
1038 | } | |
1039 | module_init(padata_driver_init); | |
1040 | ||
1041 | static __exit void padata_driver_exit(void) | |
1042 | { | |
1043 | cpuhp_remove_multi_state(hp_online); | |
1044 | } | |
1045 | module_exit(padata_driver_exit); | |
1046 | #endif |