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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 | struct parallel_data *pd; | |
68 | struct padata_instance *pinst; | |
69 | LIST_HEAD(local_list); | |
70 | ||
71 | local_bh_disable(); | |
72 | pqueue = container_of(parallel_work, | |
73 | struct padata_parallel_queue, work); | |
74 | pd = pqueue->pd; | |
75 | pinst = pd->pinst; | |
76 | ||
77 | spin_lock(&pqueue->parallel.lock); | |
78 | list_replace_init(&pqueue->parallel.list, &local_list); | |
79 | spin_unlock(&pqueue->parallel.lock); | |
80 | ||
81 | while (!list_empty(&local_list)) { | |
82 | struct padata_priv *padata; | |
83 | ||
84 | padata = list_entry(local_list.next, | |
85 | struct padata_priv, list); | |
86 | ||
87 | list_del_init(&padata->list); | |
88 | ||
89 | padata->parallel(padata); | |
90 | } | |
91 | ||
92 | local_bh_enable(); | |
93 | } | |
94 | ||
95 | /** | |
96 | * padata_do_parallel - padata parallelization function | |
97 | * | |
98 | * @pinst: padata instance | |
99 | * @padata: object to be parallelized | |
100 | * @cb_cpu: cpu the serialization callback function will run on, | |
101 | * must be in the serial cpumask of padata(i.e. cpumask.cbcpu). | |
102 | * | |
103 | * The parallelization callback function will run with BHs off. | |
104 | * Note: Every object which is parallelized by padata_do_parallel | |
105 | * must be seen by padata_do_serial. | |
106 | */ | |
107 | int padata_do_parallel(struct padata_instance *pinst, | |
108 | struct padata_priv *padata, int cb_cpu) | |
109 | { | |
110 | int target_cpu, err; | |
111 | struct padata_parallel_queue *queue; | |
112 | struct parallel_data *pd; | |
113 | ||
114 | rcu_read_lock_bh(); | |
115 | ||
116 | pd = rcu_dereference_bh(pinst->pd); | |
117 | ||
118 | err = -EINVAL; | |
119 | if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID) | |
120 | goto out; | |
121 | ||
122 | if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu)) | |
123 | goto out; | |
124 | ||
125 | err = -EBUSY; | |
126 | if ((pinst->flags & PADATA_RESET)) | |
127 | goto out; | |
128 | ||
129 | if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM) | |
130 | goto out; | |
131 | ||
132 | err = 0; | |
133 | atomic_inc(&pd->refcnt); | |
134 | padata->pd = pd; | |
135 | padata->cb_cpu = cb_cpu; | |
136 | ||
137 | target_cpu = padata_cpu_hash(pd); | |
138 | queue = per_cpu_ptr(pd->pqueue, target_cpu); | |
139 | ||
140 | spin_lock(&queue->parallel.lock); | |
141 | list_add_tail(&padata->list, &queue->parallel.list); | |
142 | spin_unlock(&queue->parallel.lock); | |
143 | ||
144 | queue_work_on(target_cpu, pinst->wq, &queue->work); | |
145 | ||
146 | out: | |
147 | rcu_read_unlock_bh(); | |
148 | ||
149 | return err; | |
150 | } | |
151 | EXPORT_SYMBOL(padata_do_parallel); | |
152 | ||
153 | /* | |
154 | * padata_get_next - Get the next object that needs serialization. | |
155 | * | |
156 | * Return values are: | |
157 | * | |
158 | * A pointer to the control struct of the next object that needs | |
159 | * serialization, if present in one of the percpu reorder queues. | |
160 | * | |
161 | * NULL, if all percpu reorder queues are empty. | |
162 | * | |
163 | * -EINPROGRESS, if the next object that needs serialization will | |
164 | * be parallel processed by another cpu and is not yet present in | |
165 | * the cpu's reorder queue. | |
166 | * | |
167 | * -ENODATA, if this cpu has to do the parallel processing for | |
168 | * the next object. | |
169 | */ | |
170 | static struct padata_priv *padata_get_next(struct parallel_data *pd) | |
171 | { | |
172 | int cpu, num_cpus; | |
173 | unsigned int next_nr, next_index; | |
174 | struct padata_parallel_queue *next_queue; | |
175 | struct padata_priv *padata; | |
176 | struct padata_list *reorder; | |
177 | ||
178 | num_cpus = cpumask_weight(pd->cpumask.pcpu); | |
179 | ||
180 | /* | |
181 | * Calculate the percpu reorder queue and the sequence | |
182 | * number of the next object. | |
183 | */ | |
184 | next_nr = pd->processed; | |
185 | next_index = next_nr % num_cpus; | |
186 | cpu = padata_index_to_cpu(pd, next_index); | |
187 | next_queue = per_cpu_ptr(pd->pqueue, cpu); | |
188 | ||
189 | padata = NULL; | |
190 | ||
191 | reorder = &next_queue->reorder; | |
192 | ||
193 | if (!list_empty(&reorder->list)) { | |
194 | padata = list_entry(reorder->list.next, | |
195 | struct padata_priv, list); | |
196 | ||
197 | spin_lock(&reorder->lock); | |
198 | list_del_init(&padata->list); | |
199 | atomic_dec(&pd->reorder_objects); | |
200 | spin_unlock(&reorder->lock); | |
201 | ||
202 | pd->processed++; | |
203 | ||
204 | goto out; | |
205 | } | |
206 | ||
207 | if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) { | |
208 | padata = ERR_PTR(-ENODATA); | |
209 | goto out; | |
210 | } | |
211 | ||
212 | padata = ERR_PTR(-EINPROGRESS); | |
213 | out: | |
214 | return padata; | |
215 | } | |
216 | ||
217 | static void padata_reorder(struct parallel_data *pd) | |
218 | { | |
219 | int cb_cpu; | |
220 | struct padata_priv *padata; | |
221 | struct padata_serial_queue *squeue; | |
222 | struct padata_instance *pinst = pd->pinst; | |
223 | ||
224 | /* | |
225 | * We need to ensure that only one cpu can work on dequeueing of | |
226 | * the reorder queue the time. Calculating in which percpu reorder | |
227 | * queue the next object will arrive takes some time. A spinlock | |
228 | * would be highly contended. Also it is not clear in which order | |
229 | * the objects arrive to the reorder queues. So a cpu could wait to | |
230 | * get the lock just to notice that there is nothing to do at the | |
231 | * moment. Therefore we use a trylock and let the holder of the lock | |
232 | * care for all the objects enqueued during the holdtime of the lock. | |
233 | */ | |
234 | if (!spin_trylock_bh(&pd->lock)) | |
235 | return; | |
236 | ||
237 | while (1) { | |
238 | padata = padata_get_next(pd); | |
239 | ||
240 | /* | |
241 | * All reorder queues are empty, or the next object that needs | |
242 | * serialization is parallel processed by another cpu and is | |
243 | * still on it's way to the cpu's reorder queue, nothing to | |
244 | * do for now. | |
245 | */ | |
246 | if (!padata || PTR_ERR(padata) == -EINPROGRESS) | |
247 | break; | |
248 | ||
249 | /* | |
250 | * This cpu has to do the parallel processing of the next | |
251 | * object. It's waiting in the cpu's parallelization queue, | |
252 | * so exit immediately. | |
253 | */ | |
254 | if (PTR_ERR(padata) == -ENODATA) { | |
255 | del_timer(&pd->timer); | |
256 | spin_unlock_bh(&pd->lock); | |
257 | return; | |
258 | } | |
259 | ||
260 | cb_cpu = padata->cb_cpu; | |
261 | squeue = per_cpu_ptr(pd->squeue, cb_cpu); | |
262 | ||
263 | spin_lock(&squeue->serial.lock); | |
264 | list_add_tail(&padata->list, &squeue->serial.list); | |
265 | spin_unlock(&squeue->serial.lock); | |
266 | ||
267 | queue_work_on(cb_cpu, pinst->wq, &squeue->work); | |
268 | } | |
269 | ||
270 | spin_unlock_bh(&pd->lock); | |
271 | ||
272 | /* | |
273 | * The next object that needs serialization might have arrived to | |
274 | * the reorder queues in the meantime, we will be called again | |
275 | * from the timer function if no one else cares for it. | |
276 | */ | |
277 | if (atomic_read(&pd->reorder_objects) | |
278 | && !(pinst->flags & PADATA_RESET)) | |
279 | mod_timer(&pd->timer, jiffies + HZ); | |
280 | else | |
281 | del_timer(&pd->timer); | |
282 | ||
283 | return; | |
284 | } | |
285 | ||
286 | static void padata_reorder_timer(unsigned long arg) | |
287 | { | |
288 | struct parallel_data *pd = (struct parallel_data *)arg; | |
289 | ||
290 | padata_reorder(pd); | |
291 | } | |
292 | ||
293 | static void padata_serial_worker(struct work_struct *serial_work) | |
294 | { | |
295 | struct padata_serial_queue *squeue; | |
296 | struct parallel_data *pd; | |
297 | LIST_HEAD(local_list); | |
298 | ||
299 | local_bh_disable(); | |
300 | squeue = container_of(serial_work, struct padata_serial_queue, work); | |
301 | pd = squeue->pd; | |
302 | ||
303 | spin_lock(&squeue->serial.lock); | |
304 | list_replace_init(&squeue->serial.list, &local_list); | |
305 | spin_unlock(&squeue->serial.lock); | |
306 | ||
307 | while (!list_empty(&local_list)) { | |
308 | struct padata_priv *padata; | |
309 | ||
310 | padata = list_entry(local_list.next, | |
311 | struct padata_priv, list); | |
312 | ||
313 | list_del_init(&padata->list); | |
314 | ||
315 | padata->serial(padata); | |
316 | atomic_dec(&pd->refcnt); | |
317 | } | |
318 | local_bh_enable(); | |
319 | } | |
320 | ||
321 | /** | |
322 | * padata_do_serial - padata serialization function | |
323 | * | |
324 | * @padata: object to be serialized. | |
325 | * | |
326 | * padata_do_serial must be called for every parallelized object. | |
327 | * The serialization callback function will run with BHs off. | |
328 | */ | |
329 | void padata_do_serial(struct padata_priv *padata) | |
330 | { | |
331 | int cpu; | |
332 | struct padata_parallel_queue *pqueue; | |
333 | struct parallel_data *pd; | |
334 | ||
335 | pd = padata->pd; | |
336 | ||
337 | cpu = get_cpu(); | |
338 | pqueue = per_cpu_ptr(pd->pqueue, cpu); | |
339 | ||
340 | spin_lock(&pqueue->reorder.lock); | |
341 | atomic_inc(&pd->reorder_objects); | |
342 | list_add_tail(&padata->list, &pqueue->reorder.list); | |
343 | spin_unlock(&pqueue->reorder.lock); | |
344 | ||
345 | put_cpu(); | |
346 | ||
347 | padata_reorder(pd); | |
348 | } | |
349 | EXPORT_SYMBOL(padata_do_serial); | |
350 | ||
351 | static int padata_setup_cpumasks(struct parallel_data *pd, | |
352 | const struct cpumask *pcpumask, | |
353 | const struct cpumask *cbcpumask) | |
354 | { | |
355 | if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL)) | |
356 | return -ENOMEM; | |
357 | ||
358 | cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask); | |
359 | if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) { | |
360 | free_cpumask_var(pd->cpumask.cbcpu); | |
361 | return -ENOMEM; | |
362 | } | |
363 | ||
364 | cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask); | |
365 | return 0; | |
366 | } | |
367 | ||
368 | static void __padata_list_init(struct padata_list *pd_list) | |
369 | { | |
370 | INIT_LIST_HEAD(&pd_list->list); | |
371 | spin_lock_init(&pd_list->lock); | |
372 | } | |
373 | ||
374 | /* Initialize all percpu queues used by serial workers */ | |
375 | static void padata_init_squeues(struct parallel_data *pd) | |
376 | { | |
377 | int cpu; | |
378 | struct padata_serial_queue *squeue; | |
379 | ||
380 | for_each_cpu(cpu, pd->cpumask.cbcpu) { | |
381 | squeue = per_cpu_ptr(pd->squeue, cpu); | |
382 | squeue->pd = pd; | |
383 | __padata_list_init(&squeue->serial); | |
384 | INIT_WORK(&squeue->work, padata_serial_worker); | |
385 | } | |
386 | } | |
387 | ||
388 | /* Initialize all percpu queues used by parallel workers */ | |
389 | static void padata_init_pqueues(struct parallel_data *pd) | |
390 | { | |
391 | int cpu_index, cpu; | |
392 | struct padata_parallel_queue *pqueue; | |
393 | ||
394 | cpu_index = 0; | |
395 | for_each_cpu(cpu, pd->cpumask.pcpu) { | |
396 | pqueue = per_cpu_ptr(pd->pqueue, cpu); | |
397 | pqueue->pd = pd; | |
398 | pqueue->cpu_index = cpu_index; | |
399 | cpu_index++; | |
400 | ||
401 | __padata_list_init(&pqueue->reorder); | |
402 | __padata_list_init(&pqueue->parallel); | |
403 | INIT_WORK(&pqueue->work, padata_parallel_worker); | |
404 | atomic_set(&pqueue->num_obj, 0); | |
405 | } | |
406 | } | |
407 | ||
408 | /* Allocate and initialize the internal cpumask dependend resources. */ | |
409 | static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst, | |
410 | const struct cpumask *pcpumask, | |
411 | const struct cpumask *cbcpumask) | |
412 | { | |
413 | struct parallel_data *pd; | |
414 | ||
415 | pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL); | |
416 | if (!pd) | |
417 | goto err; | |
418 | ||
419 | pd->pqueue = alloc_percpu(struct padata_parallel_queue); | |
420 | if (!pd->pqueue) | |
421 | goto err_free_pd; | |
422 | ||
423 | pd->squeue = alloc_percpu(struct padata_serial_queue); | |
424 | if (!pd->squeue) | |
425 | goto err_free_pqueue; | |
426 | if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0) | |
427 | goto err_free_squeue; | |
428 | ||
429 | padata_init_pqueues(pd); | |
430 | padata_init_squeues(pd); | |
431 | setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd); | |
432 | atomic_set(&pd->seq_nr, -1); | |
433 | atomic_set(&pd->reorder_objects, 0); | |
434 | atomic_set(&pd->refcnt, 0); | |
435 | pd->pinst = pinst; | |
436 | spin_lock_init(&pd->lock); | |
437 | ||
438 | return pd; | |
439 | ||
440 | err_free_squeue: | |
441 | free_percpu(pd->squeue); | |
442 | err_free_pqueue: | |
443 | free_percpu(pd->pqueue); | |
444 | err_free_pd: | |
445 | kfree(pd); | |
446 | err: | |
447 | return NULL; | |
448 | } | |
449 | ||
450 | static void padata_free_pd(struct parallel_data *pd) | |
451 | { | |
452 | free_cpumask_var(pd->cpumask.pcpu); | |
453 | free_cpumask_var(pd->cpumask.cbcpu); | |
454 | free_percpu(pd->pqueue); | |
455 | free_percpu(pd->squeue); | |
456 | kfree(pd); | |
457 | } | |
458 | ||
459 | /* Flush all objects out of the padata queues. */ | |
460 | static void padata_flush_queues(struct parallel_data *pd) | |
461 | { | |
462 | int cpu; | |
463 | struct padata_parallel_queue *pqueue; | |
464 | struct padata_serial_queue *squeue; | |
465 | ||
466 | for_each_cpu(cpu, pd->cpumask.pcpu) { | |
467 | pqueue = per_cpu_ptr(pd->pqueue, cpu); | |
468 | flush_work(&pqueue->work); | |
469 | } | |
470 | ||
471 | del_timer_sync(&pd->timer); | |
472 | ||
473 | if (atomic_read(&pd->reorder_objects)) | |
474 | padata_reorder(pd); | |
475 | ||
476 | for_each_cpu(cpu, pd->cpumask.cbcpu) { | |
477 | squeue = per_cpu_ptr(pd->squeue, cpu); | |
478 | flush_work(&squeue->work); | |
479 | } | |
480 | ||
481 | BUG_ON(atomic_read(&pd->refcnt) != 0); | |
482 | } | |
483 | ||
484 | static void __padata_start(struct padata_instance *pinst) | |
485 | { | |
486 | pinst->flags |= PADATA_INIT; | |
487 | } | |
488 | ||
489 | static void __padata_stop(struct padata_instance *pinst) | |
490 | { | |
491 | if (!(pinst->flags & PADATA_INIT)) | |
492 | return; | |
493 | ||
494 | pinst->flags &= ~PADATA_INIT; | |
495 | ||
496 | synchronize_rcu(); | |
497 | ||
498 | get_online_cpus(); | |
499 | padata_flush_queues(pinst->pd); | |
500 | put_online_cpus(); | |
501 | } | |
502 | ||
503 | /* Replace the internal control structure with a new one. */ | |
504 | static void padata_replace(struct padata_instance *pinst, | |
505 | struct parallel_data *pd_new) | |
506 | { | |
507 | struct parallel_data *pd_old = pinst->pd; | |
508 | int notification_mask = 0; | |
509 | ||
510 | pinst->flags |= PADATA_RESET; | |
511 | ||
512 | rcu_assign_pointer(pinst->pd, pd_new); | |
513 | ||
514 | synchronize_rcu(); | |
515 | ||
516 | if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu)) | |
517 | notification_mask |= PADATA_CPU_PARALLEL; | |
518 | if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu)) | |
519 | notification_mask |= PADATA_CPU_SERIAL; | |
520 | ||
521 | padata_flush_queues(pd_old); | |
522 | padata_free_pd(pd_old); | |
523 | ||
524 | if (notification_mask) | |
525 | blocking_notifier_call_chain(&pinst->cpumask_change_notifier, | |
526 | notification_mask, | |
527 | &pd_new->cpumask); | |
528 | ||
529 | pinst->flags &= ~PADATA_RESET; | |
530 | } | |
531 | ||
532 | /** | |
533 | * padata_register_cpumask_notifier - Registers a notifier that will be called | |
534 | * if either pcpu or cbcpu or both cpumasks change. | |
535 | * | |
536 | * @pinst: A poineter to padata instance | |
537 | * @nblock: A pointer to notifier block. | |
538 | */ | |
539 | int padata_register_cpumask_notifier(struct padata_instance *pinst, | |
540 | struct notifier_block *nblock) | |
541 | { | |
542 | return blocking_notifier_chain_register(&pinst->cpumask_change_notifier, | |
543 | nblock); | |
544 | } | |
545 | EXPORT_SYMBOL(padata_register_cpumask_notifier); | |
546 | ||
547 | /** | |
548 | * padata_unregister_cpumask_notifier - Unregisters cpumask notifier | |
549 | * registered earlier using padata_register_cpumask_notifier | |
550 | * | |
551 | * @pinst: A pointer to data instance. | |
552 | * @nlock: A pointer to notifier block. | |
553 | */ | |
554 | int padata_unregister_cpumask_notifier(struct padata_instance *pinst, | |
555 | struct notifier_block *nblock) | |
556 | { | |
557 | return blocking_notifier_chain_unregister( | |
558 | &pinst->cpumask_change_notifier, | |
559 | nblock); | |
560 | } | |
561 | EXPORT_SYMBOL(padata_unregister_cpumask_notifier); | |
562 | ||
563 | ||
564 | /* If cpumask contains no active cpu, we mark the instance as invalid. */ | |
565 | static bool padata_validate_cpumask(struct padata_instance *pinst, | |
566 | const struct cpumask *cpumask) | |
567 | { | |
568 | if (!cpumask_intersects(cpumask, cpu_online_mask)) { | |
569 | pinst->flags |= PADATA_INVALID; | |
570 | return false; | |
571 | } | |
572 | ||
573 | pinst->flags &= ~PADATA_INVALID; | |
574 | return true; | |
575 | } | |
576 | ||
577 | static int __padata_set_cpumasks(struct padata_instance *pinst, | |
578 | cpumask_var_t pcpumask, | |
579 | cpumask_var_t cbcpumask) | |
580 | { | |
581 | int valid; | |
582 | struct parallel_data *pd; | |
583 | ||
584 | valid = padata_validate_cpumask(pinst, pcpumask); | |
585 | if (!valid) { | |
586 | __padata_stop(pinst); | |
587 | goto out_replace; | |
588 | } | |
589 | ||
590 | valid = padata_validate_cpumask(pinst, cbcpumask); | |
591 | if (!valid) | |
592 | __padata_stop(pinst); | |
593 | ||
594 | out_replace: | |
595 | pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); | |
596 | if (!pd) | |
597 | return -ENOMEM; | |
598 | ||
599 | cpumask_copy(pinst->cpumask.pcpu, pcpumask); | |
600 | cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); | |
601 | ||
602 | padata_replace(pinst, pd); | |
603 | ||
604 | if (valid) | |
605 | __padata_start(pinst); | |
606 | ||
607 | return 0; | |
608 | } | |
609 | ||
610 | /** | |
611 | * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value | |
612 | * equivalent to @cpumask. | |
613 | * | |
614 | * @pinst: padata instance | |
615 | * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding | |
616 | * to parallel and serial cpumasks respectively. | |
617 | * @cpumask: the cpumask to use | |
618 | */ | |
619 | int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, | |
620 | cpumask_var_t cpumask) | |
621 | { | |
622 | struct cpumask *serial_mask, *parallel_mask; | |
623 | int err = -EINVAL; | |
624 | ||
625 | mutex_lock(&pinst->lock); | |
626 | get_online_cpus(); | |
627 | ||
628 | switch (cpumask_type) { | |
629 | case PADATA_CPU_PARALLEL: | |
630 | serial_mask = pinst->cpumask.cbcpu; | |
631 | parallel_mask = cpumask; | |
632 | break; | |
633 | case PADATA_CPU_SERIAL: | |
634 | parallel_mask = pinst->cpumask.pcpu; | |
635 | serial_mask = cpumask; | |
636 | break; | |
637 | default: | |
638 | goto out; | |
639 | } | |
640 | ||
641 | err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask); | |
642 | ||
643 | out: | |
644 | put_online_cpus(); | |
645 | mutex_unlock(&pinst->lock); | |
646 | ||
647 | return err; | |
648 | } | |
649 | EXPORT_SYMBOL(padata_set_cpumask); | |
650 | ||
651 | /** | |
652 | * padata_start - start the parallel processing | |
653 | * | |
654 | * @pinst: padata instance to start | |
655 | */ | |
656 | int padata_start(struct padata_instance *pinst) | |
657 | { | |
658 | int err = 0; | |
659 | ||
660 | mutex_lock(&pinst->lock); | |
661 | ||
662 | if (pinst->flags & PADATA_INVALID) | |
663 | err = -EINVAL; | |
664 | ||
665 | __padata_start(pinst); | |
666 | ||
667 | mutex_unlock(&pinst->lock); | |
668 | ||
669 | return err; | |
670 | } | |
671 | EXPORT_SYMBOL(padata_start); | |
672 | ||
673 | /** | |
674 | * padata_stop - stop the parallel processing | |
675 | * | |
676 | * @pinst: padata instance to stop | |
677 | */ | |
678 | void padata_stop(struct padata_instance *pinst) | |
679 | { | |
680 | mutex_lock(&pinst->lock); | |
681 | __padata_stop(pinst); | |
682 | mutex_unlock(&pinst->lock); | |
683 | } | |
684 | EXPORT_SYMBOL(padata_stop); | |
685 | ||
686 | #ifdef CONFIG_HOTPLUG_CPU | |
687 | ||
688 | static int __padata_add_cpu(struct padata_instance *pinst, int cpu) | |
689 | { | |
690 | struct parallel_data *pd; | |
691 | ||
692 | if (cpumask_test_cpu(cpu, cpu_online_mask)) { | |
693 | pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, | |
694 | pinst->cpumask.cbcpu); | |
695 | if (!pd) | |
696 | return -ENOMEM; | |
697 | ||
698 | padata_replace(pinst, pd); | |
699 | ||
700 | if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) && | |
701 | padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) | |
702 | __padata_start(pinst); | |
703 | } | |
704 | ||
705 | return 0; | |
706 | } | |
707 | ||
708 | static int __padata_remove_cpu(struct padata_instance *pinst, int cpu) | |
709 | { | |
710 | struct parallel_data *pd = NULL; | |
711 | ||
712 | if (cpumask_test_cpu(cpu, cpu_online_mask)) { | |
713 | ||
714 | if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) || | |
715 | !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) | |
716 | __padata_stop(pinst); | |
717 | ||
718 | pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, | |
719 | pinst->cpumask.cbcpu); | |
720 | if (!pd) | |
721 | return -ENOMEM; | |
722 | ||
723 | padata_replace(pinst, pd); | |
724 | ||
725 | cpumask_clear_cpu(cpu, pd->cpumask.cbcpu); | |
726 | cpumask_clear_cpu(cpu, pd->cpumask.pcpu); | |
727 | } | |
728 | ||
729 | return 0; | |
730 | } | |
731 | ||
732 | /** | |
733 | * padata_remove_cpu - remove a cpu from the one or both(serial and parallel) | |
734 | * padata cpumasks. | |
735 | * | |
736 | * @pinst: padata instance | |
737 | * @cpu: cpu to remove | |
738 | * @mask: bitmask specifying from which cpumask @cpu should be removed | |
739 | * The @mask may be any combination of the following flags: | |
740 | * PADATA_CPU_SERIAL - serial cpumask | |
741 | * PADATA_CPU_PARALLEL - parallel cpumask | |
742 | */ | |
743 | int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask) | |
744 | { | |
745 | int err; | |
746 | ||
747 | if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL))) | |
748 | return -EINVAL; | |
749 | ||
750 | mutex_lock(&pinst->lock); | |
751 | ||
752 | get_online_cpus(); | |
753 | if (mask & PADATA_CPU_SERIAL) | |
754 | cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu); | |
755 | if (mask & PADATA_CPU_PARALLEL) | |
756 | cpumask_clear_cpu(cpu, pinst->cpumask.pcpu); | |
757 | ||
758 | err = __padata_remove_cpu(pinst, cpu); | |
759 | put_online_cpus(); | |
760 | ||
761 | mutex_unlock(&pinst->lock); | |
762 | ||
763 | return err; | |
764 | } | |
765 | EXPORT_SYMBOL(padata_remove_cpu); | |
766 | ||
767 | static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu) | |
768 | { | |
769 | return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) || | |
770 | cpumask_test_cpu(cpu, pinst->cpumask.cbcpu); | |
771 | } | |
772 | ||
773 | static int padata_cpu_online(unsigned int cpu, struct hlist_node *node) | |
774 | { | |
775 | struct padata_instance *pinst; | |
776 | int ret; | |
777 | ||
778 | pinst = hlist_entry_safe(node, struct padata_instance, node); | |
779 | if (!pinst_has_cpu(pinst, cpu)) | |
780 | return 0; | |
781 | ||
782 | mutex_lock(&pinst->lock); | |
783 | ret = __padata_add_cpu(pinst, cpu); | |
784 | mutex_unlock(&pinst->lock); | |
785 | return ret; | |
786 | } | |
787 | ||
788 | static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node) | |
789 | { | |
790 | struct padata_instance *pinst; | |
791 | int ret; | |
792 | ||
793 | pinst = hlist_entry_safe(node, struct padata_instance, node); | |
794 | if (!pinst_has_cpu(pinst, cpu)) | |
795 | return 0; | |
796 | ||
797 | mutex_lock(&pinst->lock); | |
798 | ret = __padata_remove_cpu(pinst, cpu); | |
799 | mutex_unlock(&pinst->lock); | |
800 | return ret; | |
801 | } | |
802 | ||
803 | static enum cpuhp_state hp_online; | |
804 | #endif | |
805 | ||
806 | static void __padata_free(struct padata_instance *pinst) | |
807 | { | |
808 | #ifdef CONFIG_HOTPLUG_CPU | |
809 | cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node); | |
810 | #endif | |
811 | ||
812 | padata_stop(pinst); | |
813 | padata_free_pd(pinst->pd); | |
814 | free_cpumask_var(pinst->cpumask.pcpu); | |
815 | free_cpumask_var(pinst->cpumask.cbcpu); | |
816 | kfree(pinst); | |
817 | } | |
818 | ||
819 | #define kobj2pinst(_kobj) \ | |
820 | container_of(_kobj, struct padata_instance, kobj) | |
821 | #define attr2pentry(_attr) \ | |
822 | container_of(_attr, struct padata_sysfs_entry, attr) | |
823 | ||
824 | static void padata_sysfs_release(struct kobject *kobj) | |
825 | { | |
826 | struct padata_instance *pinst = kobj2pinst(kobj); | |
827 | __padata_free(pinst); | |
828 | } | |
829 | ||
830 | struct padata_sysfs_entry { | |
831 | struct attribute attr; | |
832 | ssize_t (*show)(struct padata_instance *, struct attribute *, char *); | |
833 | ssize_t (*store)(struct padata_instance *, struct attribute *, | |
834 | const char *, size_t); | |
835 | }; | |
836 | ||
837 | static ssize_t show_cpumask(struct padata_instance *pinst, | |
838 | struct attribute *attr, char *buf) | |
839 | { | |
840 | struct cpumask *cpumask; | |
841 | ssize_t len; | |
842 | ||
843 | mutex_lock(&pinst->lock); | |
844 | if (!strcmp(attr->name, "serial_cpumask")) | |
845 | cpumask = pinst->cpumask.cbcpu; | |
846 | else | |
847 | cpumask = pinst->cpumask.pcpu; | |
848 | ||
849 | len = snprintf(buf, PAGE_SIZE, "%*pb\n", | |
850 | nr_cpu_ids, cpumask_bits(cpumask)); | |
851 | mutex_unlock(&pinst->lock); | |
852 | return len < PAGE_SIZE ? len : -EINVAL; | |
853 | } | |
854 | ||
855 | static ssize_t store_cpumask(struct padata_instance *pinst, | |
856 | struct attribute *attr, | |
857 | const char *buf, size_t count) | |
858 | { | |
859 | cpumask_var_t new_cpumask; | |
860 | ssize_t ret; | |
861 | int mask_type; | |
862 | ||
863 | if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL)) | |
864 | return -ENOMEM; | |
865 | ||
866 | ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask), | |
867 | nr_cpumask_bits); | |
868 | if (ret < 0) | |
869 | goto out; | |
870 | ||
871 | mask_type = !strcmp(attr->name, "serial_cpumask") ? | |
872 | PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL; | |
873 | ret = padata_set_cpumask(pinst, mask_type, new_cpumask); | |
874 | if (!ret) | |
875 | ret = count; | |
876 | ||
877 | out: | |
878 | free_cpumask_var(new_cpumask); | |
879 | return ret; | |
880 | } | |
881 | ||
882 | #define PADATA_ATTR_RW(_name, _show_name, _store_name) \ | |
883 | static struct padata_sysfs_entry _name##_attr = \ | |
884 | __ATTR(_name, 0644, _show_name, _store_name) | |
885 | #define PADATA_ATTR_RO(_name, _show_name) \ | |
886 | static struct padata_sysfs_entry _name##_attr = \ | |
887 | __ATTR(_name, 0400, _show_name, NULL) | |
888 | ||
889 | PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask); | |
890 | PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask); | |
891 | ||
892 | /* | |
893 | * Padata sysfs provides the following objects: | |
894 | * serial_cpumask [RW] - cpumask for serial workers | |
895 | * parallel_cpumask [RW] - cpumask for parallel workers | |
896 | */ | |
897 | static struct attribute *padata_default_attrs[] = { | |
898 | &serial_cpumask_attr.attr, | |
899 | ¶llel_cpumask_attr.attr, | |
900 | NULL, | |
901 | }; | |
902 | ||
903 | static ssize_t padata_sysfs_show(struct kobject *kobj, | |
904 | struct attribute *attr, char *buf) | |
905 | { | |
906 | struct padata_instance *pinst; | |
907 | struct padata_sysfs_entry *pentry; | |
908 | ssize_t ret = -EIO; | |
909 | ||
910 | pinst = kobj2pinst(kobj); | |
911 | pentry = attr2pentry(attr); | |
912 | if (pentry->show) | |
913 | ret = pentry->show(pinst, attr, buf); | |
914 | ||
915 | return ret; | |
916 | } | |
917 | ||
918 | static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr, | |
919 | const char *buf, size_t count) | |
920 | { | |
921 | struct padata_instance *pinst; | |
922 | struct padata_sysfs_entry *pentry; | |
923 | ssize_t ret = -EIO; | |
924 | ||
925 | pinst = kobj2pinst(kobj); | |
926 | pentry = attr2pentry(attr); | |
927 | if (pentry->show) | |
928 | ret = pentry->store(pinst, attr, buf, count); | |
929 | ||
930 | return ret; | |
931 | } | |
932 | ||
933 | static const struct sysfs_ops padata_sysfs_ops = { | |
934 | .show = padata_sysfs_show, | |
935 | .store = padata_sysfs_store, | |
936 | }; | |
937 | ||
938 | static struct kobj_type padata_attr_type = { | |
939 | .sysfs_ops = &padata_sysfs_ops, | |
940 | .default_attrs = padata_default_attrs, | |
941 | .release = padata_sysfs_release, | |
942 | }; | |
943 | ||
944 | /** | |
945 | * padata_alloc_possible - Allocate and initialize padata instance. | |
946 | * Use the cpu_possible_mask for serial and | |
947 | * parallel workers. | |
948 | * | |
949 | * @wq: workqueue to use for the allocated padata instance | |
950 | */ | |
951 | struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq) | |
952 | { | |
953 | return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask); | |
954 | } | |
955 | EXPORT_SYMBOL(padata_alloc_possible); | |
956 | ||
957 | /** | |
958 | * padata_alloc - allocate and initialize a padata instance and specify | |
959 | * cpumasks for serial and parallel workers. | |
960 | * | |
961 | * @wq: workqueue to use for the allocated padata instance | |
962 | * @pcpumask: cpumask that will be used for padata parallelization | |
963 | * @cbcpumask: cpumask that will be used for padata serialization | |
964 | */ | |
965 | struct padata_instance *padata_alloc(struct workqueue_struct *wq, | |
966 | const struct cpumask *pcpumask, | |
967 | const struct cpumask *cbcpumask) | |
968 | { | |
969 | struct padata_instance *pinst; | |
970 | struct parallel_data *pd = NULL; | |
971 | ||
972 | pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL); | |
973 | if (!pinst) | |
974 | goto err; | |
975 | ||
976 | get_online_cpus(); | |
977 | if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL)) | |
978 | goto err_free_inst; | |
979 | if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) { | |
980 | free_cpumask_var(pinst->cpumask.pcpu); | |
981 | goto err_free_inst; | |
982 | } | |
983 | if (!padata_validate_cpumask(pinst, pcpumask) || | |
984 | !padata_validate_cpumask(pinst, cbcpumask)) | |
985 | goto err_free_masks; | |
986 | ||
987 | pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); | |
988 | if (!pd) | |
989 | goto err_free_masks; | |
990 | ||
991 | rcu_assign_pointer(pinst->pd, pd); | |
992 | ||
993 | pinst->wq = wq; | |
994 | ||
995 | cpumask_copy(pinst->cpumask.pcpu, pcpumask); | |
996 | cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); | |
997 | ||
998 | pinst->flags = 0; | |
999 | ||
1000 | put_online_cpus(); | |
1001 | ||
1002 | BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier); | |
1003 | kobject_init(&pinst->kobj, &padata_attr_type); | |
1004 | mutex_init(&pinst->lock); | |
1005 | ||
1006 | #ifdef CONFIG_HOTPLUG_CPU | |
1007 | cpuhp_state_add_instance_nocalls(hp_online, &pinst->node); | |
1008 | #endif | |
1009 | return pinst; | |
1010 | ||
1011 | err_free_masks: | |
1012 | free_cpumask_var(pinst->cpumask.pcpu); | |
1013 | free_cpumask_var(pinst->cpumask.cbcpu); | |
1014 | err_free_inst: | |
1015 | kfree(pinst); | |
1016 | put_online_cpus(); | |
1017 | err: | |
1018 | return NULL; | |
1019 | } | |
1020 | ||
1021 | /** | |
1022 | * padata_free - free a padata instance | |
1023 | * | |
1024 | * @padata_inst: padata instance to free | |
1025 | */ | |
1026 | void padata_free(struct padata_instance *pinst) | |
1027 | { | |
1028 | kobject_put(&pinst->kobj); | |
1029 | } | |
1030 | EXPORT_SYMBOL(padata_free); | |
1031 | ||
1032 | #ifdef CONFIG_HOTPLUG_CPU | |
1033 | ||
1034 | static __init int padata_driver_init(void) | |
1035 | { | |
1036 | int ret; | |
1037 | ||
1038 | ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online", | |
1039 | padata_cpu_online, | |
1040 | padata_cpu_prep_down); | |
1041 | if (ret < 0) | |
1042 | return ret; | |
1043 | hp_online = ret; | |
1044 | return 0; | |
1045 | } | |
1046 | module_init(padata_driver_init); | |
1047 | ||
1048 | static __exit void padata_driver_exit(void) | |
1049 | { | |
1050 | cpuhp_remove_multi_state(hp_online); | |
1051 | } | |
1052 | module_exit(padata_driver_exit); | |
1053 | #endif |