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1/*
2 * padata.c - generic interface to process data streams in parallel
3 *
4 * Copyright (C) 2008, 2009 secunet Security Networks AG
5 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21#include <linux/module.h>
22#include <linux/cpumask.h>
23#include <linux/err.h>
24#include <linux/cpu.h>
25#include <linux/padata.h>
26#include <linux/mutex.h>
27#include <linux/sched.h>
28#include <linux/slab.h>
29#include <linux/sysfs.h>
30#include <linux/rcupdate.h>
31
32#define MAX_SEQ_NR (INT_MAX - NR_CPUS)
33#define MAX_OBJ_NUM 1000
34
35static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
36{
37 int cpu, target_cpu;
38
39 target_cpu = cpumask_first(pd->cpumask.pcpu);
40 for (cpu = 0; cpu < cpu_index; cpu++)
41 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
42
43 return target_cpu;
44}
45
46static int padata_cpu_hash(struct padata_priv *padata)
47{
48 int cpu_index;
49 struct parallel_data *pd;
50
51 pd = padata->pd;
52
53 /*
54 * Hash the sequence numbers to the cpus by taking
55 * seq_nr mod. number of cpus in use.
56 */
57 cpu_index = padata->seq_nr % cpumask_weight(pd->cpumask.pcpu);
58
59 return padata_index_to_cpu(pd, cpu_index);
60}
61
62static void padata_parallel_worker(struct work_struct *parallel_work)
63{
64 struct padata_parallel_queue *pqueue;
65 struct parallel_data *pd;
66 struct padata_instance *pinst;
67 LIST_HEAD(local_list);
68
69 local_bh_disable();
70 pqueue = container_of(parallel_work,
71 struct padata_parallel_queue, work);
72 pd = pqueue->pd;
73 pinst = pd->pinst;
74
75 spin_lock(&pqueue->parallel.lock);
76 list_replace_init(&pqueue->parallel.list, &local_list);
77 spin_unlock(&pqueue->parallel.lock);
78
79 while (!list_empty(&local_list)) {
80 struct padata_priv *padata;
81
82 padata = list_entry(local_list.next,
83 struct padata_priv, list);
84
85 list_del_init(&padata->list);
86
87 padata->parallel(padata);
88 }
89
90 local_bh_enable();
91}
92
93/**
94 * padata_do_parallel - padata parallelization function
95 *
96 * @pinst: padata instance
97 * @padata: object to be parallelized
98 * @cb_cpu: cpu the serialization callback function will run on,
99 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
100 *
101 * The parallelization callback function will run with BHs off.
102 * Note: Every object which is parallelized by padata_do_parallel
103 * must be seen by padata_do_serial.
104 */
105int padata_do_parallel(struct padata_instance *pinst,
106 struct padata_priv *padata, int cb_cpu)
107{
108 int target_cpu, err;
109 struct padata_parallel_queue *queue;
110 struct parallel_data *pd;
111
112 rcu_read_lock_bh();
113
114 pd = rcu_dereference(pinst->pd);
115
116 err = -EINVAL;
117 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
118 goto out;
119
120 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
121 goto out;
122
123 err = -EBUSY;
124 if ((pinst->flags & PADATA_RESET))
125 goto out;
126
127 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
128 goto out;
129
130 err = 0;
131 atomic_inc(&pd->refcnt);
132 padata->pd = pd;
133 padata->cb_cpu = cb_cpu;
134
135 if (unlikely(atomic_read(&pd->seq_nr) == pd->max_seq_nr))
136 atomic_set(&pd->seq_nr, -1);
137
138 padata->seq_nr = atomic_inc_return(&pd->seq_nr);
139
140 target_cpu = padata_cpu_hash(padata);
141 queue = per_cpu_ptr(pd->pqueue, target_cpu);
142
143 spin_lock(&queue->parallel.lock);
144 list_add_tail(&padata->list, &queue->parallel.list);
145 spin_unlock(&queue->parallel.lock);
146
147 queue_work_on(target_cpu, pinst->wq, &queue->work);
148
149out:
150 rcu_read_unlock_bh();
151
152 return err;
153}
154EXPORT_SYMBOL(padata_do_parallel);
155
156/*
157 * padata_get_next - Get the next object that needs serialization.
158 *
159 * Return values are:
160 *
161 * A pointer to the control struct of the next object that needs
162 * serialization, if present in one of the percpu reorder queues.
163 *
164 * NULL, if all percpu reorder queues are empty.
165 *
166 * -EINPROGRESS, if the next object that needs serialization will
167 * be parallel processed by another cpu and is not yet present in
168 * the cpu's reorder queue.
169 *
170 * -ENODATA, if this cpu has to do the parallel processing for
171 * the next object.
172 */
173static struct padata_priv *padata_get_next(struct parallel_data *pd)
174{
175 int cpu, num_cpus;
176 int next_nr, next_index;
177 struct padata_parallel_queue *queue, *next_queue;
178 struct padata_priv *padata;
179 struct padata_list *reorder;
180
181 num_cpus = cpumask_weight(pd->cpumask.pcpu);
182
183 /*
184 * Calculate the percpu reorder queue and the sequence
185 * number of the next object.
186 */
187 next_nr = pd->processed;
188 next_index = next_nr % num_cpus;
189 cpu = padata_index_to_cpu(pd, next_index);
190 next_queue = per_cpu_ptr(pd->pqueue, cpu);
191
192 if (unlikely(next_nr > pd->max_seq_nr)) {
193 next_nr = next_nr - pd->max_seq_nr - 1;
194 next_index = next_nr % num_cpus;
195 cpu = padata_index_to_cpu(pd, next_index);
196 next_queue = per_cpu_ptr(pd->pqueue, cpu);
197 pd->processed = 0;
198 }
199
200 padata = NULL;
201
202 reorder = &next_queue->reorder;
203
204 if (!list_empty(&reorder->list)) {
205 padata = list_entry(reorder->list.next,
206 struct padata_priv, list);
207
208 BUG_ON(next_nr != padata->seq_nr);
209
210 spin_lock(&reorder->lock);
211 list_del_init(&padata->list);
212 atomic_dec(&pd->reorder_objects);
213 spin_unlock(&reorder->lock);
214
215 pd->processed++;
216
217 goto out;
218 }
219
220 queue = per_cpu_ptr(pd->pqueue, smp_processor_id());
221 if (queue->cpu_index == next_queue->cpu_index) {
222 padata = ERR_PTR(-ENODATA);
223 goto out;
224 }
225
226 padata = ERR_PTR(-EINPROGRESS);
227out:
228 return padata;
229}
230
231static void padata_reorder(struct parallel_data *pd)
232{
233 struct padata_priv *padata;
234 struct padata_serial_queue *squeue;
235 struct padata_instance *pinst = pd->pinst;
236
237 /*
238 * We need to ensure that only one cpu can work on dequeueing of
239 * the reorder queue the time. Calculating in which percpu reorder
240 * queue the next object will arrive takes some time. A spinlock
241 * would be highly contended. Also it is not clear in which order
242 * the objects arrive to the reorder queues. So a cpu could wait to
243 * get the lock just to notice that there is nothing to do at the
244 * moment. Therefore we use a trylock and let the holder of the lock
245 * care for all the objects enqueued during the holdtime of the lock.
246 */
247 if (!spin_trylock_bh(&pd->lock))
248 return;
249
250 while (1) {
251 padata = padata_get_next(pd);
252
253 /*
254 * All reorder queues are empty, or the next object that needs
255 * serialization is parallel processed by another cpu and is
256 * still on it's way to the cpu's reorder queue, nothing to
257 * do for now.
258 */
259 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
260 break;
261
262 /*
263 * This cpu has to do the parallel processing of the next
264 * object. It's waiting in the cpu's parallelization queue,
265 * so exit immediately.
266 */
267 if (PTR_ERR(padata) == -ENODATA) {
268 del_timer(&pd->timer);
269 spin_unlock_bh(&pd->lock);
270 return;
271 }
272
273 squeue = per_cpu_ptr(pd->squeue, padata->cb_cpu);
274
275 spin_lock(&squeue->serial.lock);
276 list_add_tail(&padata->list, &squeue->serial.list);
277 spin_unlock(&squeue->serial.lock);
278
279 queue_work_on(padata->cb_cpu, pinst->wq, &squeue->work);
280 }
281
282 spin_unlock_bh(&pd->lock);
283
284 /*
285 * The next object that needs serialization might have arrived to
286 * the reorder queues in the meantime, we will be called again
287 * from the timer function if no one else cares for it.
288 */
289 if (atomic_read(&pd->reorder_objects)
290 && !(pinst->flags & PADATA_RESET))
291 mod_timer(&pd->timer, jiffies + HZ);
292 else
293 del_timer(&pd->timer);
294
295 return;
296}
297
298static void padata_reorder_timer(unsigned long arg)
299{
300 struct parallel_data *pd = (struct parallel_data *)arg;
301
302 padata_reorder(pd);
303}
304
305static void padata_serial_worker(struct work_struct *serial_work)
306{
307 struct padata_serial_queue *squeue;
308 struct parallel_data *pd;
309 LIST_HEAD(local_list);
310
311 local_bh_disable();
312 squeue = container_of(serial_work, struct padata_serial_queue, work);
313 pd = squeue->pd;
314
315 spin_lock(&squeue->serial.lock);
316 list_replace_init(&squeue->serial.list, &local_list);
317 spin_unlock(&squeue->serial.lock);
318
319 while (!list_empty(&local_list)) {
320 struct padata_priv *padata;
321
322 padata = list_entry(local_list.next,
323 struct padata_priv, list);
324
325 list_del_init(&padata->list);
326
327 padata->serial(padata);
328 atomic_dec(&pd->refcnt);
329 }
330 local_bh_enable();
331}
332
333/**
334 * padata_do_serial - padata serialization function
335 *
336 * @padata: object to be serialized.
337 *
338 * padata_do_serial must be called for every parallelized object.
339 * The serialization callback function will run with BHs off.
340 */
341void padata_do_serial(struct padata_priv *padata)
342{
343 int cpu;
344 struct padata_parallel_queue *pqueue;
345 struct parallel_data *pd;
346
347 pd = padata->pd;
348
349 cpu = get_cpu();
350 pqueue = per_cpu_ptr(pd->pqueue, cpu);
351
352 spin_lock(&pqueue->reorder.lock);
353 atomic_inc(&pd->reorder_objects);
354 list_add_tail(&padata->list, &pqueue->reorder.list);
355 spin_unlock(&pqueue->reorder.lock);
356
357 put_cpu();
358
359 padata_reorder(pd);
360}
361EXPORT_SYMBOL(padata_do_serial);
362
363static int padata_setup_cpumasks(struct parallel_data *pd,
364 const struct cpumask *pcpumask,
365 const struct cpumask *cbcpumask)
366{
367 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
368 return -ENOMEM;
369
370 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_active_mask);
371 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
372 free_cpumask_var(pd->cpumask.cbcpu);
373 return -ENOMEM;
374 }
375
376 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_active_mask);
377 return 0;
378}
379
380static void __padata_list_init(struct padata_list *pd_list)
381{
382 INIT_LIST_HEAD(&pd_list->list);
383 spin_lock_init(&pd_list->lock);
384}
385
386/* Initialize all percpu queues used by serial workers */
387static void padata_init_squeues(struct parallel_data *pd)
388{
389 int cpu;
390 struct padata_serial_queue *squeue;
391
392 for_each_cpu(cpu, pd->cpumask.cbcpu) {
393 squeue = per_cpu_ptr(pd->squeue, cpu);
394 squeue->pd = pd;
395 __padata_list_init(&squeue->serial);
396 INIT_WORK(&squeue->work, padata_serial_worker);
397 }
398}
399
400/* Initialize all percpu queues used by parallel workers */
401static void padata_init_pqueues(struct parallel_data *pd)
402{
403 int cpu_index, num_cpus, cpu;
404 struct padata_parallel_queue *pqueue;
405
406 cpu_index = 0;
407 for_each_cpu(cpu, pd->cpumask.pcpu) {
408 pqueue = per_cpu_ptr(pd->pqueue, cpu);
409 pqueue->pd = pd;
410 pqueue->cpu_index = cpu_index;
411 cpu_index++;
412
413 __padata_list_init(&pqueue->reorder);
414 __padata_list_init(&pqueue->parallel);
415 INIT_WORK(&pqueue->work, padata_parallel_worker);
416 atomic_set(&pqueue->num_obj, 0);
417 }
418
419 num_cpus = cpumask_weight(pd->cpumask.pcpu);
420 pd->max_seq_nr = num_cpus ? (MAX_SEQ_NR / num_cpus) * num_cpus - 1 : 0;
421}
422
423/* Allocate and initialize the internal cpumask dependend resources. */
424static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
425 const struct cpumask *pcpumask,
426 const struct cpumask *cbcpumask)
427{
428 struct parallel_data *pd;
429
430 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
431 if (!pd)
432 goto err;
433
434 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
435 if (!pd->pqueue)
436 goto err_free_pd;
437
438 pd->squeue = alloc_percpu(struct padata_serial_queue);
439 if (!pd->squeue)
440 goto err_free_pqueue;
441 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
442 goto err_free_squeue;
443
444 padata_init_pqueues(pd);
445 padata_init_squeues(pd);
446 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
447 atomic_set(&pd->seq_nr, -1);
448 atomic_set(&pd->reorder_objects, 0);
449 atomic_set(&pd->refcnt, 0);
450 pd->pinst = pinst;
451 spin_lock_init(&pd->lock);
452
453 return pd;
454
455err_free_squeue:
456 free_percpu(pd->squeue);
457err_free_pqueue:
458 free_percpu(pd->pqueue);
459err_free_pd:
460 kfree(pd);
461err:
462 return NULL;
463}
464
465static void padata_free_pd(struct parallel_data *pd)
466{
467 free_cpumask_var(pd->cpumask.pcpu);
468 free_cpumask_var(pd->cpumask.cbcpu);
469 free_percpu(pd->pqueue);
470 free_percpu(pd->squeue);
471 kfree(pd);
472}
473
474/* Flush all objects out of the padata queues. */
475static void padata_flush_queues(struct parallel_data *pd)
476{
477 int cpu;
478 struct padata_parallel_queue *pqueue;
479 struct padata_serial_queue *squeue;
480
481 for_each_cpu(cpu, pd->cpumask.pcpu) {
482 pqueue = per_cpu_ptr(pd->pqueue, cpu);
483 flush_work(&pqueue->work);
484 }
485
486 del_timer_sync(&pd->timer);
487
488 if (atomic_read(&pd->reorder_objects))
489 padata_reorder(pd);
490
491 for_each_cpu(cpu, pd->cpumask.cbcpu) {
492 squeue = per_cpu_ptr(pd->squeue, cpu);
493 flush_work(&squeue->work);
494 }
495
496 BUG_ON(atomic_read(&pd->refcnt) != 0);
497}
498
499static void __padata_start(struct padata_instance *pinst)
500{
501 pinst->flags |= PADATA_INIT;
502}
503
504static void __padata_stop(struct padata_instance *pinst)
505{
506 if (!(pinst->flags & PADATA_INIT))
507 return;
508
509 pinst->flags &= ~PADATA_INIT;
510
511 synchronize_rcu();
512
513 get_online_cpus();
514 padata_flush_queues(pinst->pd);
515 put_online_cpus();
516}
517
518/* Replace the internal control structure with a new one. */
519static void padata_replace(struct padata_instance *pinst,
520 struct parallel_data *pd_new)
521{
522 struct parallel_data *pd_old = pinst->pd;
523 int notification_mask = 0;
524
525 pinst->flags |= PADATA_RESET;
526
527 rcu_assign_pointer(pinst->pd, pd_new);
528
529 synchronize_rcu();
530
531 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
532 notification_mask |= PADATA_CPU_PARALLEL;
533 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
534 notification_mask |= PADATA_CPU_SERIAL;
535
536 padata_flush_queues(pd_old);
537 padata_free_pd(pd_old);
538
539 if (notification_mask)
540 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
541 notification_mask,
542 &pd_new->cpumask);
543
544 pinst->flags &= ~PADATA_RESET;
545}
546
547/**
548 * padata_register_cpumask_notifier - Registers a notifier that will be called
549 * if either pcpu or cbcpu or both cpumasks change.
550 *
551 * @pinst: A poineter to padata instance
552 * @nblock: A pointer to notifier block.
553 */
554int padata_register_cpumask_notifier(struct padata_instance *pinst,
555 struct notifier_block *nblock)
556{
557 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
558 nblock);
559}
560EXPORT_SYMBOL(padata_register_cpumask_notifier);
561
562/**
563 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
564 * registered earlier using padata_register_cpumask_notifier
565 *
566 * @pinst: A pointer to data instance.
567 * @nlock: A pointer to notifier block.
568 */
569int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
570 struct notifier_block *nblock)
571{
572 return blocking_notifier_chain_unregister(
573 &pinst->cpumask_change_notifier,
574 nblock);
575}
576EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
577
578
579/* If cpumask contains no active cpu, we mark the instance as invalid. */
580static bool padata_validate_cpumask(struct padata_instance *pinst,
581 const struct cpumask *cpumask)
582{
583 if (!cpumask_intersects(cpumask, cpu_active_mask)) {
584 pinst->flags |= PADATA_INVALID;
585 return false;
586 }
587
588 pinst->flags &= ~PADATA_INVALID;
589 return true;
590}
591
592static int __padata_set_cpumasks(struct padata_instance *pinst,
593 cpumask_var_t pcpumask,
594 cpumask_var_t cbcpumask)
595{
596 int valid;
597 struct parallel_data *pd;
598
599 valid = padata_validate_cpumask(pinst, pcpumask);
600 if (!valid) {
601 __padata_stop(pinst);
602 goto out_replace;
603 }
604
605 valid = padata_validate_cpumask(pinst, cbcpumask);
606 if (!valid)
607 __padata_stop(pinst);
608
609out_replace:
610 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
611 if (!pd)
612 return -ENOMEM;
613
614 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
615 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
616
617 padata_replace(pinst, pd);
618
619 if (valid)
620 __padata_start(pinst);
621
622 return 0;
623}
624
625/**
626 * padata_set_cpumasks - Set both parallel and serial cpumasks. The first
627 * one is used by parallel workers and the second one
628 * by the wokers doing serialization.
629 *
630 * @pinst: padata instance
631 * @pcpumask: the cpumask to use for parallel workers
632 * @cbcpumask: the cpumsak to use for serial workers
633 */
634int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
635 cpumask_var_t cbcpumask)
636{
637 int err;
638
639 mutex_lock(&pinst->lock);
640 get_online_cpus();
641
642 err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
643
644 put_online_cpus();
645 mutex_unlock(&pinst->lock);
646
647 return err;
648
649}
650EXPORT_SYMBOL(padata_set_cpumasks);
651
652/**
653 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
654 * equivalent to @cpumask.
655 *
656 * @pinst: padata instance
657 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
658 * to parallel and serial cpumasks respectively.
659 * @cpumask: the cpumask to use
660 */
661int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
662 cpumask_var_t cpumask)
663{
664 struct cpumask *serial_mask, *parallel_mask;
665 int err = -EINVAL;
666
667 mutex_lock(&pinst->lock);
668 get_online_cpus();
669
670 switch (cpumask_type) {
671 case PADATA_CPU_PARALLEL:
672 serial_mask = pinst->cpumask.cbcpu;
673 parallel_mask = cpumask;
674 break;
675 case PADATA_CPU_SERIAL:
676 parallel_mask = pinst->cpumask.pcpu;
677 serial_mask = cpumask;
678 break;
679 default:
680 goto out;
681 }
682
683 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
684
685out:
686 put_online_cpus();
687 mutex_unlock(&pinst->lock);
688
689 return err;
690}
691EXPORT_SYMBOL(padata_set_cpumask);
692
693static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
694{
695 struct parallel_data *pd;
696
697 if (cpumask_test_cpu(cpu, cpu_active_mask)) {
698 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
699 pinst->cpumask.cbcpu);
700 if (!pd)
701 return -ENOMEM;
702
703 padata_replace(pinst, pd);
704
705 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
706 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
707 __padata_start(pinst);
708 }
709
710 return 0;
711}
712
713 /**
714 * padata_add_cpu - add a cpu to one or both(parallel and serial)
715 * padata cpumasks.
716 *
717 * @pinst: padata instance
718 * @cpu: cpu to add
719 * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
720 * The @mask may be any combination of the following flags:
721 * PADATA_CPU_SERIAL - serial cpumask
722 * PADATA_CPU_PARALLEL - parallel cpumask
723 */
724
725int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask)
726{
727 int err;
728
729 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
730 return -EINVAL;
731
732 mutex_lock(&pinst->lock);
733
734 get_online_cpus();
735 if (mask & PADATA_CPU_SERIAL)
736 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu);
737 if (mask & PADATA_CPU_PARALLEL)
738 cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
739
740 err = __padata_add_cpu(pinst, cpu);
741 put_online_cpus();
742
743 mutex_unlock(&pinst->lock);
744
745 return err;
746}
747EXPORT_SYMBOL(padata_add_cpu);
748
749static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
750{
751 struct parallel_data *pd = NULL;
752
753 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
754
755 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
756 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
757 __padata_stop(pinst);
758
759 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
760 pinst->cpumask.cbcpu);
761 if (!pd)
762 return -ENOMEM;
763
764 padata_replace(pinst, pd);
765 }
766
767 return 0;
768}
769
770 /**
771 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
772 * padata cpumasks.
773 *
774 * @pinst: padata instance
775 * @cpu: cpu to remove
776 * @mask: bitmask specifying from which cpumask @cpu should be removed
777 * The @mask may be any combination of the following flags:
778 * PADATA_CPU_SERIAL - serial cpumask
779 * PADATA_CPU_PARALLEL - parallel cpumask
780 */
781int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
782{
783 int err;
784
785 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
786 return -EINVAL;
787
788 mutex_lock(&pinst->lock);
789
790 get_online_cpus();
791 if (mask & PADATA_CPU_SERIAL)
792 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
793 if (mask & PADATA_CPU_PARALLEL)
794 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
795
796 err = __padata_remove_cpu(pinst, cpu);
797 put_online_cpus();
798
799 mutex_unlock(&pinst->lock);
800
801 return err;
802}
803EXPORT_SYMBOL(padata_remove_cpu);
804
805/**
806 * padata_start - start the parallel processing
807 *
808 * @pinst: padata instance to start
809 */
810int padata_start(struct padata_instance *pinst)
811{
812 int err = 0;
813
814 mutex_lock(&pinst->lock);
815
816 if (pinst->flags & PADATA_INVALID)
817 err =-EINVAL;
818
819 __padata_start(pinst);
820
821 mutex_unlock(&pinst->lock);
822
823 return err;
824}
825EXPORT_SYMBOL(padata_start);
826
827/**
828 * padata_stop - stop the parallel processing
829 *
830 * @pinst: padata instance to stop
831 */
832void padata_stop(struct padata_instance *pinst)
833{
834 mutex_lock(&pinst->lock);
835 __padata_stop(pinst);
836 mutex_unlock(&pinst->lock);
837}
838EXPORT_SYMBOL(padata_stop);
839
840#ifdef CONFIG_HOTPLUG_CPU
841
842static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
843{
844 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
845 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
846}
847
848
849static int padata_cpu_callback(struct notifier_block *nfb,
850 unsigned long action, void *hcpu)
851{
852 int err;
853 struct padata_instance *pinst;
854 int cpu = (unsigned long)hcpu;
855
856 pinst = container_of(nfb, struct padata_instance, cpu_notifier);
857
858 switch (action) {
859 case CPU_ONLINE:
860 case CPU_ONLINE_FROZEN:
861 if (!pinst_has_cpu(pinst, cpu))
862 break;
863 mutex_lock(&pinst->lock);
864 err = __padata_add_cpu(pinst, cpu);
865 mutex_unlock(&pinst->lock);
866 if (err)
867 return notifier_from_errno(err);
868 break;
869
870 case CPU_DOWN_PREPARE:
871 case CPU_DOWN_PREPARE_FROZEN:
872 if (!pinst_has_cpu(pinst, cpu))
873 break;
874 mutex_lock(&pinst->lock);
875 err = __padata_remove_cpu(pinst, cpu);
876 mutex_unlock(&pinst->lock);
877 if (err)
878 return notifier_from_errno(err);
879 break;
880
881 case CPU_UP_CANCELED:
882 case CPU_UP_CANCELED_FROZEN:
883 if (!pinst_has_cpu(pinst, cpu))
884 break;
885 mutex_lock(&pinst->lock);
886 __padata_remove_cpu(pinst, cpu);
887 mutex_unlock(&pinst->lock);
888
889 case CPU_DOWN_FAILED:
890 case CPU_DOWN_FAILED_FROZEN:
891 if (!pinst_has_cpu(pinst, cpu))
892 break;
893 mutex_lock(&pinst->lock);
894 __padata_add_cpu(pinst, cpu);
895 mutex_unlock(&pinst->lock);
896 }
897
898 return NOTIFY_OK;
899}
900#endif
901
902static void __padata_free(struct padata_instance *pinst)
903{
904#ifdef CONFIG_HOTPLUG_CPU
905 unregister_hotcpu_notifier(&pinst->cpu_notifier);
906#endif
907
908 padata_stop(pinst);
909 padata_free_pd(pinst->pd);
910 free_cpumask_var(pinst->cpumask.pcpu);
911 free_cpumask_var(pinst->cpumask.cbcpu);
912 kfree(pinst);
913}
914
915#define kobj2pinst(_kobj) \
916 container_of(_kobj, struct padata_instance, kobj)
917#define attr2pentry(_attr) \
918 container_of(_attr, struct padata_sysfs_entry, attr)
919
920static void padata_sysfs_release(struct kobject *kobj)
921{
922 struct padata_instance *pinst = kobj2pinst(kobj);
923 __padata_free(pinst);
924}
925
926struct padata_sysfs_entry {
927 struct attribute attr;
928 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
929 ssize_t (*store)(struct padata_instance *, struct attribute *,
930 const char *, size_t);
931};
932
933static ssize_t show_cpumask(struct padata_instance *pinst,
934 struct attribute *attr, char *buf)
935{
936 struct cpumask *cpumask;
937 ssize_t len;
938
939 mutex_lock(&pinst->lock);
940 if (!strcmp(attr->name, "serial_cpumask"))
941 cpumask = pinst->cpumask.cbcpu;
942 else
943 cpumask = pinst->cpumask.pcpu;
944
945 len = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask),
946 nr_cpu_ids);
947 if (PAGE_SIZE - len < 2)
948 len = -EINVAL;
949 else
950 len += sprintf(buf + len, "\n");
951
952 mutex_unlock(&pinst->lock);
953 return len;
954}
955
956static ssize_t store_cpumask(struct padata_instance *pinst,
957 struct attribute *attr,
958 const char *buf, size_t count)
959{
960 cpumask_var_t new_cpumask;
961 ssize_t ret;
962 int mask_type;
963
964 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
965 return -ENOMEM;
966
967 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
968 nr_cpumask_bits);
969 if (ret < 0)
970 goto out;
971
972 mask_type = !strcmp(attr->name, "serial_cpumask") ?
973 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
974 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
975 if (!ret)
976 ret = count;
977
978out:
979 free_cpumask_var(new_cpumask);
980 return ret;
981}
982
983#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
984 static struct padata_sysfs_entry _name##_attr = \
985 __ATTR(_name, 0644, _show_name, _store_name)
986#define PADATA_ATTR_RO(_name, _show_name) \
987 static struct padata_sysfs_entry _name##_attr = \
988 __ATTR(_name, 0400, _show_name, NULL)
989
990PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
991PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
992
993/*
994 * Padata sysfs provides the following objects:
995 * serial_cpumask [RW] - cpumask for serial workers
996 * parallel_cpumask [RW] - cpumask for parallel workers
997 */
998static struct attribute *padata_default_attrs[] = {
999 &serial_cpumask_attr.attr,
1000 ¶llel_cpumask_attr.attr,
1001 NULL,
1002};
1003
1004static ssize_t padata_sysfs_show(struct kobject *kobj,
1005 struct attribute *attr, char *buf)
1006{
1007 struct padata_instance *pinst;
1008 struct padata_sysfs_entry *pentry;
1009 ssize_t ret = -EIO;
1010
1011 pinst = kobj2pinst(kobj);
1012 pentry = attr2pentry(attr);
1013 if (pentry->show)
1014 ret = pentry->show(pinst, attr, buf);
1015
1016 return ret;
1017}
1018
1019static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
1020 const char *buf, size_t count)
1021{
1022 struct padata_instance *pinst;
1023 struct padata_sysfs_entry *pentry;
1024 ssize_t ret = -EIO;
1025
1026 pinst = kobj2pinst(kobj);
1027 pentry = attr2pentry(attr);
1028 if (pentry->show)
1029 ret = pentry->store(pinst, attr, buf, count);
1030
1031 return ret;
1032}
1033
1034static const struct sysfs_ops padata_sysfs_ops = {
1035 .show = padata_sysfs_show,
1036 .store = padata_sysfs_store,
1037};
1038
1039static struct kobj_type padata_attr_type = {
1040 .sysfs_ops = &padata_sysfs_ops,
1041 .default_attrs = padata_default_attrs,
1042 .release = padata_sysfs_release,
1043};
1044
1045/**
1046 * padata_alloc_possible - Allocate and initialize padata instance.
1047 * Use the cpu_possible_mask for serial and
1048 * parallel workers.
1049 *
1050 * @wq: workqueue to use for the allocated padata instance
1051 */
1052struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1053{
1054 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1055}
1056EXPORT_SYMBOL(padata_alloc_possible);
1057
1058/**
1059 * padata_alloc - allocate and initialize a padata instance and specify
1060 * cpumasks for serial and parallel workers.
1061 *
1062 * @wq: workqueue to use for the allocated padata instance
1063 * @pcpumask: cpumask that will be used for padata parallelization
1064 * @cbcpumask: cpumask that will be used for padata serialization
1065 */
1066struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1067 const struct cpumask *pcpumask,
1068 const struct cpumask *cbcpumask)
1069{
1070 struct padata_instance *pinst;
1071 struct parallel_data *pd = NULL;
1072
1073 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1074 if (!pinst)
1075 goto err;
1076
1077 get_online_cpus();
1078 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1079 goto err_free_inst;
1080 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1081 free_cpumask_var(pinst->cpumask.pcpu);
1082 goto err_free_inst;
1083 }
1084 if (!padata_validate_cpumask(pinst, pcpumask) ||
1085 !padata_validate_cpumask(pinst, cbcpumask))
1086 goto err_free_masks;
1087
1088 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1089 if (!pd)
1090 goto err_free_masks;
1091
1092 rcu_assign_pointer(pinst->pd, pd);
1093
1094 pinst->wq = wq;
1095
1096 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1097 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1098
1099 pinst->flags = 0;
1100
1101#ifdef CONFIG_HOTPLUG_CPU
1102 pinst->cpu_notifier.notifier_call = padata_cpu_callback;
1103 pinst->cpu_notifier.priority = 0;
1104 register_hotcpu_notifier(&pinst->cpu_notifier);
1105#endif
1106
1107 put_online_cpus();
1108
1109 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1110 kobject_init(&pinst->kobj, &padata_attr_type);
1111 mutex_init(&pinst->lock);
1112
1113 return pinst;
1114
1115err_free_masks:
1116 free_cpumask_var(pinst->cpumask.pcpu);
1117 free_cpumask_var(pinst->cpumask.cbcpu);
1118err_free_inst:
1119 kfree(pinst);
1120 put_online_cpus();
1121err:
1122 return NULL;
1123}
1124EXPORT_SYMBOL(padata_alloc);
1125
1126/**
1127 * padata_free - free a padata instance
1128 *
1129 * @padata_inst: padata instance to free
1130 */
1131void padata_free(struct padata_instance *pinst)
1132{
1133 kobject_put(&pinst->kobj);
1134}
1135EXPORT_SYMBOL(padata_free);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * padata.c - generic interface to process data streams in parallel
4 *
5 * See Documentation/padata.txt for an api documentation.
6 *
7 * Copyright (C) 2008, 2009 secunet Security Networks AG
8 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms and conditions of the GNU General Public License,
12 * version 2, as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
17 * more details.
18 *
19 * You should have received a copy of the GNU General Public License along with
20 * this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
22 */
23
24#include <linux/export.h>
25#include <linux/cpumask.h>
26#include <linux/err.h>
27#include <linux/cpu.h>
28#include <linux/padata.h>
29#include <linux/mutex.h>
30#include <linux/sched.h>
31#include <linux/slab.h>
32#include <linux/sysfs.h>
33#include <linux/rcupdate.h>
34#include <linux/module.h>
35
36#define MAX_OBJ_NUM 1000
37
38static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
39{
40 int cpu, target_cpu;
41
42 target_cpu = cpumask_first(pd->cpumask.pcpu);
43 for (cpu = 0; cpu < cpu_index; cpu++)
44 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
45
46 return target_cpu;
47}
48
49static int padata_cpu_hash(struct parallel_data *pd)
50{
51 unsigned int seq_nr;
52 int cpu_index;
53
54 /*
55 * Hash the sequence numbers to the cpus by taking
56 * seq_nr mod. number of cpus in use.
57 */
58
59 seq_nr = atomic_inc_return(&pd->seq_nr);
60 cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
61
62 return padata_index_to_cpu(pd, cpu_index);
63}
64
65static void padata_parallel_worker(struct work_struct *parallel_work)
66{
67 struct padata_parallel_queue *pqueue;
68 LIST_HEAD(local_list);
69
70 local_bh_disable();
71 pqueue = container_of(parallel_work,
72 struct padata_parallel_queue, work);
73
74 spin_lock(&pqueue->parallel.lock);
75 list_replace_init(&pqueue->parallel.list, &local_list);
76 spin_unlock(&pqueue->parallel.lock);
77
78 while (!list_empty(&local_list)) {
79 struct padata_priv *padata;
80
81 padata = list_entry(local_list.next,
82 struct padata_priv, list);
83
84 list_del_init(&padata->list);
85
86 padata->parallel(padata);
87 }
88
89 local_bh_enable();
90}
91
92/**
93 * padata_do_parallel - padata parallelization function
94 *
95 * @pinst: padata instance
96 * @padata: object to be parallelized
97 * @cb_cpu: cpu the serialization callback function will run on,
98 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
99 *
100 * The parallelization callback function will run with BHs off.
101 * Note: Every object which is parallelized by padata_do_parallel
102 * must be seen by padata_do_serial.
103 */
104int padata_do_parallel(struct padata_instance *pinst,
105 struct padata_priv *padata, int cb_cpu)
106{
107 int target_cpu, err;
108 struct padata_parallel_queue *queue;
109 struct parallel_data *pd;
110
111 rcu_read_lock_bh();
112
113 pd = rcu_dereference_bh(pinst->pd);
114
115 err = -EINVAL;
116 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
117 goto out;
118
119 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
120 goto out;
121
122 err = -EBUSY;
123 if ((pinst->flags & PADATA_RESET))
124 goto out;
125
126 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
127 goto out;
128
129 err = 0;
130 atomic_inc(&pd->refcnt);
131 padata->pd = pd;
132 padata->cb_cpu = cb_cpu;
133
134 target_cpu = padata_cpu_hash(pd);
135 padata->cpu = target_cpu;
136 queue = per_cpu_ptr(pd->pqueue, target_cpu);
137
138 spin_lock(&queue->parallel.lock);
139 list_add_tail(&padata->list, &queue->parallel.list);
140 spin_unlock(&queue->parallel.lock);
141
142 queue_work_on(target_cpu, pinst->wq, &queue->work);
143
144out:
145 rcu_read_unlock_bh();
146
147 return err;
148}
149EXPORT_SYMBOL(padata_do_parallel);
150
151/*
152 * padata_get_next - Get the next object that needs serialization.
153 *
154 * Return values are:
155 *
156 * A pointer to the control struct of the next object that needs
157 * serialization, if present in one of the percpu reorder queues.
158 *
159 * -EINPROGRESS, if the next object that needs serialization will
160 * be parallel processed by another cpu and is not yet present in
161 * the cpu's reorder queue.
162 *
163 * -ENODATA, if this cpu has to do the parallel processing for
164 * the next object.
165 */
166static struct padata_priv *padata_get_next(struct parallel_data *pd)
167{
168 int cpu, num_cpus;
169 unsigned int next_nr, next_index;
170 struct padata_parallel_queue *next_queue;
171 struct padata_priv *padata;
172 struct padata_list *reorder;
173
174 num_cpus = cpumask_weight(pd->cpumask.pcpu);
175
176 /*
177 * Calculate the percpu reorder queue and the sequence
178 * number of the next object.
179 */
180 next_nr = pd->processed;
181 next_index = next_nr % num_cpus;
182 cpu = padata_index_to_cpu(pd, next_index);
183 next_queue = per_cpu_ptr(pd->pqueue, cpu);
184
185 reorder = &next_queue->reorder;
186
187 spin_lock(&reorder->lock);
188 if (!list_empty(&reorder->list)) {
189 padata = list_entry(reorder->list.next,
190 struct padata_priv, list);
191
192 list_del_init(&padata->list);
193 atomic_dec(&pd->reorder_objects);
194
195 pd->processed++;
196
197 spin_unlock(&reorder->lock);
198 goto out;
199 }
200 spin_unlock(&reorder->lock);
201
202 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
203 padata = ERR_PTR(-ENODATA);
204 goto out;
205 }
206
207 padata = ERR_PTR(-EINPROGRESS);
208out:
209 return padata;
210}
211
212static void padata_reorder(struct parallel_data *pd)
213{
214 int cb_cpu;
215 struct padata_priv *padata;
216 struct padata_serial_queue *squeue;
217 struct padata_instance *pinst = pd->pinst;
218
219 /*
220 * We need to ensure that only one cpu can work on dequeueing of
221 * the reorder queue the time. Calculating in which percpu reorder
222 * queue the next object will arrive takes some time. A spinlock
223 * would be highly contended. Also it is not clear in which order
224 * the objects arrive to the reorder queues. So a cpu could wait to
225 * get the lock just to notice that there is nothing to do at the
226 * moment. Therefore we use a trylock and let the holder of the lock
227 * care for all the objects enqueued during the holdtime of the lock.
228 */
229 if (!spin_trylock_bh(&pd->lock))
230 return;
231
232 while (1) {
233 padata = padata_get_next(pd);
234
235 /*
236 * If the next object that needs serialization is parallel
237 * processed by another cpu and is still on it's way to the
238 * cpu's reorder queue, nothing to do for now.
239 */
240 if (PTR_ERR(padata) == -EINPROGRESS)
241 break;
242
243 /*
244 * This cpu has to do the parallel processing of the next
245 * object. It's waiting in the cpu's parallelization queue,
246 * so exit immediately.
247 */
248 if (PTR_ERR(padata) == -ENODATA) {
249 del_timer(&pd->timer);
250 spin_unlock_bh(&pd->lock);
251 return;
252 }
253
254 cb_cpu = padata->cb_cpu;
255 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
256
257 spin_lock(&squeue->serial.lock);
258 list_add_tail(&padata->list, &squeue->serial.list);
259 spin_unlock(&squeue->serial.lock);
260
261 queue_work_on(cb_cpu, pinst->wq, &squeue->work);
262 }
263
264 spin_unlock_bh(&pd->lock);
265
266 /*
267 * The next object that needs serialization might have arrived to
268 * the reorder queues in the meantime, we will be called again
269 * from the timer function if no one else cares for it.
270 */
271 if (atomic_read(&pd->reorder_objects)
272 && !(pinst->flags & PADATA_RESET))
273 mod_timer(&pd->timer, jiffies + HZ);
274 else
275 del_timer(&pd->timer);
276
277 return;
278}
279
280static void invoke_padata_reorder(struct work_struct *work)
281{
282 struct padata_parallel_queue *pqueue;
283 struct parallel_data *pd;
284
285 local_bh_disable();
286 pqueue = container_of(work, struct padata_parallel_queue, reorder_work);
287 pd = pqueue->pd;
288 padata_reorder(pd);
289 local_bh_enable();
290}
291
292static void padata_reorder_timer(struct timer_list *t)
293{
294 struct parallel_data *pd = from_timer(pd, t, timer);
295 unsigned int weight;
296 int target_cpu, cpu;
297
298 cpu = get_cpu();
299
300 /* We don't lock pd here to not interfere with parallel processing
301 * padata_reorder() calls on other CPUs. We just need any CPU out of
302 * the cpumask.pcpu set. It would be nice if it's the right one but
303 * it doesn't matter if we're off to the next one by using an outdated
304 * pd->processed value.
305 */
306 weight = cpumask_weight(pd->cpumask.pcpu);
307 target_cpu = padata_index_to_cpu(pd, pd->processed % weight);
308
309 /* ensure to call the reorder callback on the correct CPU */
310 if (cpu != target_cpu) {
311 struct padata_parallel_queue *pqueue;
312 struct padata_instance *pinst;
313
314 /* The timer function is serialized wrt itself -- no locking
315 * needed.
316 */
317 pinst = pd->pinst;
318 pqueue = per_cpu_ptr(pd->pqueue, target_cpu);
319 queue_work_on(target_cpu, pinst->wq, &pqueue->reorder_work);
320 } else {
321 padata_reorder(pd);
322 }
323
324 put_cpu();
325}
326
327static void padata_serial_worker(struct work_struct *serial_work)
328{
329 struct padata_serial_queue *squeue;
330 struct parallel_data *pd;
331 LIST_HEAD(local_list);
332
333 local_bh_disable();
334 squeue = container_of(serial_work, struct padata_serial_queue, work);
335 pd = squeue->pd;
336
337 spin_lock(&squeue->serial.lock);
338 list_replace_init(&squeue->serial.list, &local_list);
339 spin_unlock(&squeue->serial.lock);
340
341 while (!list_empty(&local_list)) {
342 struct padata_priv *padata;
343
344 padata = list_entry(local_list.next,
345 struct padata_priv, list);
346
347 list_del_init(&padata->list);
348
349 padata->serial(padata);
350 atomic_dec(&pd->refcnt);
351 }
352 local_bh_enable();
353}
354
355/**
356 * padata_do_serial - padata serialization function
357 *
358 * @padata: object to be serialized.
359 *
360 * padata_do_serial must be called for every parallelized object.
361 * The serialization callback function will run with BHs off.
362 */
363void padata_do_serial(struct padata_priv *padata)
364{
365 int cpu;
366 struct padata_parallel_queue *pqueue;
367 struct parallel_data *pd;
368 int reorder_via_wq = 0;
369
370 pd = padata->pd;
371
372 cpu = get_cpu();
373
374 /* We need to run on the same CPU padata_do_parallel(.., padata, ..)
375 * was called on -- or, at least, enqueue the padata object into the
376 * correct per-cpu queue.
377 */
378 if (cpu != padata->cpu) {
379 reorder_via_wq = 1;
380 cpu = padata->cpu;
381 }
382
383 pqueue = per_cpu_ptr(pd->pqueue, cpu);
384
385 spin_lock(&pqueue->reorder.lock);
386 atomic_inc(&pd->reorder_objects);
387 list_add_tail(&padata->list, &pqueue->reorder.list);
388 spin_unlock(&pqueue->reorder.lock);
389
390 put_cpu();
391
392 /* If we're running on the wrong CPU, call padata_reorder() via a
393 * kernel worker.
394 */
395 if (reorder_via_wq)
396 queue_work_on(cpu, pd->pinst->wq, &pqueue->reorder_work);
397 else
398 padata_reorder(pd);
399}
400EXPORT_SYMBOL(padata_do_serial);
401
402static int padata_setup_cpumasks(struct parallel_data *pd,
403 const struct cpumask *pcpumask,
404 const struct cpumask *cbcpumask)
405{
406 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
407 return -ENOMEM;
408
409 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
410 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
411 free_cpumask_var(pd->cpumask.pcpu);
412 return -ENOMEM;
413 }
414
415 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
416 return 0;
417}
418
419static void __padata_list_init(struct padata_list *pd_list)
420{
421 INIT_LIST_HEAD(&pd_list->list);
422 spin_lock_init(&pd_list->lock);
423}
424
425/* Initialize all percpu queues used by serial workers */
426static void padata_init_squeues(struct parallel_data *pd)
427{
428 int cpu;
429 struct padata_serial_queue *squeue;
430
431 for_each_cpu(cpu, pd->cpumask.cbcpu) {
432 squeue = per_cpu_ptr(pd->squeue, cpu);
433 squeue->pd = pd;
434 __padata_list_init(&squeue->serial);
435 INIT_WORK(&squeue->work, padata_serial_worker);
436 }
437}
438
439/* Initialize all percpu queues used by parallel workers */
440static void padata_init_pqueues(struct parallel_data *pd)
441{
442 int cpu_index, cpu;
443 struct padata_parallel_queue *pqueue;
444
445 cpu_index = 0;
446 for_each_possible_cpu(cpu) {
447 pqueue = per_cpu_ptr(pd->pqueue, cpu);
448
449 if (!cpumask_test_cpu(cpu, pd->cpumask.pcpu)) {
450 pqueue->cpu_index = -1;
451 continue;
452 }
453
454 pqueue->pd = pd;
455 pqueue->cpu_index = cpu_index;
456 cpu_index++;
457
458 __padata_list_init(&pqueue->reorder);
459 __padata_list_init(&pqueue->parallel);
460 INIT_WORK(&pqueue->work, padata_parallel_worker);
461 INIT_WORK(&pqueue->reorder_work, invoke_padata_reorder);
462 atomic_set(&pqueue->num_obj, 0);
463 }
464}
465
466/* Allocate and initialize the internal cpumask dependend resources. */
467static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
468 const struct cpumask *pcpumask,
469 const struct cpumask *cbcpumask)
470{
471 struct parallel_data *pd;
472
473 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
474 if (!pd)
475 goto err;
476
477 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
478 if (!pd->pqueue)
479 goto err_free_pd;
480
481 pd->squeue = alloc_percpu(struct padata_serial_queue);
482 if (!pd->squeue)
483 goto err_free_pqueue;
484 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
485 goto err_free_squeue;
486
487 padata_init_pqueues(pd);
488 padata_init_squeues(pd);
489 timer_setup(&pd->timer, padata_reorder_timer, 0);
490 atomic_set(&pd->seq_nr, -1);
491 atomic_set(&pd->reorder_objects, 0);
492 atomic_set(&pd->refcnt, 0);
493 pd->pinst = pinst;
494 spin_lock_init(&pd->lock);
495
496 return pd;
497
498err_free_squeue:
499 free_percpu(pd->squeue);
500err_free_pqueue:
501 free_percpu(pd->pqueue);
502err_free_pd:
503 kfree(pd);
504err:
505 return NULL;
506}
507
508static void padata_free_pd(struct parallel_data *pd)
509{
510 free_cpumask_var(pd->cpumask.pcpu);
511 free_cpumask_var(pd->cpumask.cbcpu);
512 free_percpu(pd->pqueue);
513 free_percpu(pd->squeue);
514 kfree(pd);
515}
516
517/* Flush all objects out of the padata queues. */
518static void padata_flush_queues(struct parallel_data *pd)
519{
520 int cpu;
521 struct padata_parallel_queue *pqueue;
522 struct padata_serial_queue *squeue;
523
524 for_each_cpu(cpu, pd->cpumask.pcpu) {
525 pqueue = per_cpu_ptr(pd->pqueue, cpu);
526 flush_work(&pqueue->work);
527 }
528
529 del_timer_sync(&pd->timer);
530
531 if (atomic_read(&pd->reorder_objects))
532 padata_reorder(pd);
533
534 for_each_cpu(cpu, pd->cpumask.cbcpu) {
535 squeue = per_cpu_ptr(pd->squeue, cpu);
536 flush_work(&squeue->work);
537 }
538
539 BUG_ON(atomic_read(&pd->refcnt) != 0);
540}
541
542static void __padata_start(struct padata_instance *pinst)
543{
544 pinst->flags |= PADATA_INIT;
545}
546
547static void __padata_stop(struct padata_instance *pinst)
548{
549 if (!(pinst->flags & PADATA_INIT))
550 return;
551
552 pinst->flags &= ~PADATA_INIT;
553
554 synchronize_rcu();
555
556 get_online_cpus();
557 padata_flush_queues(pinst->pd);
558 put_online_cpus();
559}
560
561/* Replace the internal control structure with a new one. */
562static void padata_replace(struct padata_instance *pinst,
563 struct parallel_data *pd_new)
564{
565 struct parallel_data *pd_old = pinst->pd;
566 int notification_mask = 0;
567
568 pinst->flags |= PADATA_RESET;
569
570 rcu_assign_pointer(pinst->pd, pd_new);
571
572 synchronize_rcu();
573
574 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
575 notification_mask |= PADATA_CPU_PARALLEL;
576 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
577 notification_mask |= PADATA_CPU_SERIAL;
578
579 padata_flush_queues(pd_old);
580 padata_free_pd(pd_old);
581
582 if (notification_mask)
583 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
584 notification_mask,
585 &pd_new->cpumask);
586
587 pinst->flags &= ~PADATA_RESET;
588}
589
590/**
591 * padata_register_cpumask_notifier - Registers a notifier that will be called
592 * if either pcpu or cbcpu or both cpumasks change.
593 *
594 * @pinst: A poineter to padata instance
595 * @nblock: A pointer to notifier block.
596 */
597int padata_register_cpumask_notifier(struct padata_instance *pinst,
598 struct notifier_block *nblock)
599{
600 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
601 nblock);
602}
603EXPORT_SYMBOL(padata_register_cpumask_notifier);
604
605/**
606 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
607 * registered earlier using padata_register_cpumask_notifier
608 *
609 * @pinst: A pointer to data instance.
610 * @nlock: A pointer to notifier block.
611 */
612int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
613 struct notifier_block *nblock)
614{
615 return blocking_notifier_chain_unregister(
616 &pinst->cpumask_change_notifier,
617 nblock);
618}
619EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
620
621
622/* If cpumask contains no active cpu, we mark the instance as invalid. */
623static bool padata_validate_cpumask(struct padata_instance *pinst,
624 const struct cpumask *cpumask)
625{
626 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
627 pinst->flags |= PADATA_INVALID;
628 return false;
629 }
630
631 pinst->flags &= ~PADATA_INVALID;
632 return true;
633}
634
635static int __padata_set_cpumasks(struct padata_instance *pinst,
636 cpumask_var_t pcpumask,
637 cpumask_var_t cbcpumask)
638{
639 int valid;
640 struct parallel_data *pd;
641
642 valid = padata_validate_cpumask(pinst, pcpumask);
643 if (!valid) {
644 __padata_stop(pinst);
645 goto out_replace;
646 }
647
648 valid = padata_validate_cpumask(pinst, cbcpumask);
649 if (!valid)
650 __padata_stop(pinst);
651
652out_replace:
653 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
654 if (!pd)
655 return -ENOMEM;
656
657 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
658 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
659
660 padata_replace(pinst, pd);
661
662 if (valid)
663 __padata_start(pinst);
664
665 return 0;
666}
667
668/**
669 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
670 * equivalent to @cpumask.
671 *
672 * @pinst: padata instance
673 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
674 * to parallel and serial cpumasks respectively.
675 * @cpumask: the cpumask to use
676 */
677int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
678 cpumask_var_t cpumask)
679{
680 struct cpumask *serial_mask, *parallel_mask;
681 int err = -EINVAL;
682
683 mutex_lock(&pinst->lock);
684 get_online_cpus();
685
686 switch (cpumask_type) {
687 case PADATA_CPU_PARALLEL:
688 serial_mask = pinst->cpumask.cbcpu;
689 parallel_mask = cpumask;
690 break;
691 case PADATA_CPU_SERIAL:
692 parallel_mask = pinst->cpumask.pcpu;
693 serial_mask = cpumask;
694 break;
695 default:
696 goto out;
697 }
698
699 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
700
701out:
702 put_online_cpus();
703 mutex_unlock(&pinst->lock);
704
705 return err;
706}
707EXPORT_SYMBOL(padata_set_cpumask);
708
709/**
710 * padata_start - start the parallel processing
711 *
712 * @pinst: padata instance to start
713 */
714int padata_start(struct padata_instance *pinst)
715{
716 int err = 0;
717
718 mutex_lock(&pinst->lock);
719
720 if (pinst->flags & PADATA_INVALID)
721 err = -EINVAL;
722
723 __padata_start(pinst);
724
725 mutex_unlock(&pinst->lock);
726
727 return err;
728}
729EXPORT_SYMBOL(padata_start);
730
731/**
732 * padata_stop - stop the parallel processing
733 *
734 * @pinst: padata instance to stop
735 */
736void padata_stop(struct padata_instance *pinst)
737{
738 mutex_lock(&pinst->lock);
739 __padata_stop(pinst);
740 mutex_unlock(&pinst->lock);
741}
742EXPORT_SYMBOL(padata_stop);
743
744#ifdef CONFIG_HOTPLUG_CPU
745
746static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
747{
748 struct parallel_data *pd;
749
750 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
751 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
752 pinst->cpumask.cbcpu);
753 if (!pd)
754 return -ENOMEM;
755
756 padata_replace(pinst, pd);
757
758 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
759 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
760 __padata_start(pinst);
761 }
762
763 return 0;
764}
765
766static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
767{
768 struct parallel_data *pd = NULL;
769
770 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
771
772 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
773 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
774 __padata_stop(pinst);
775
776 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
777 pinst->cpumask.cbcpu);
778 if (!pd)
779 return -ENOMEM;
780
781 padata_replace(pinst, pd);
782
783 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
784 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
785 }
786
787 return 0;
788}
789
790 /**
791 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
792 * padata cpumasks.
793 *
794 * @pinst: padata instance
795 * @cpu: cpu to remove
796 * @mask: bitmask specifying from which cpumask @cpu should be removed
797 * The @mask may be any combination of the following flags:
798 * PADATA_CPU_SERIAL - serial cpumask
799 * PADATA_CPU_PARALLEL - parallel cpumask
800 */
801int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
802{
803 int err;
804
805 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
806 return -EINVAL;
807
808 mutex_lock(&pinst->lock);
809
810 get_online_cpus();
811 if (mask & PADATA_CPU_SERIAL)
812 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
813 if (mask & PADATA_CPU_PARALLEL)
814 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
815
816 err = __padata_remove_cpu(pinst, cpu);
817 put_online_cpus();
818
819 mutex_unlock(&pinst->lock);
820
821 return err;
822}
823EXPORT_SYMBOL(padata_remove_cpu);
824
825static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
826{
827 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
828 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
829}
830
831static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
832{
833 struct padata_instance *pinst;
834 int ret;
835
836 pinst = hlist_entry_safe(node, struct padata_instance, node);
837 if (!pinst_has_cpu(pinst, cpu))
838 return 0;
839
840 mutex_lock(&pinst->lock);
841 ret = __padata_add_cpu(pinst, cpu);
842 mutex_unlock(&pinst->lock);
843 return ret;
844}
845
846static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
847{
848 struct padata_instance *pinst;
849 int ret;
850
851 pinst = hlist_entry_safe(node, struct padata_instance, node);
852 if (!pinst_has_cpu(pinst, cpu))
853 return 0;
854
855 mutex_lock(&pinst->lock);
856 ret = __padata_remove_cpu(pinst, cpu);
857 mutex_unlock(&pinst->lock);
858 return ret;
859}
860
861static enum cpuhp_state hp_online;
862#endif
863
864static void __padata_free(struct padata_instance *pinst)
865{
866#ifdef CONFIG_HOTPLUG_CPU
867 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
868#endif
869
870 padata_stop(pinst);
871 padata_free_pd(pinst->pd);
872 free_cpumask_var(pinst->cpumask.pcpu);
873 free_cpumask_var(pinst->cpumask.cbcpu);
874 kfree(pinst);
875}
876
877#define kobj2pinst(_kobj) \
878 container_of(_kobj, struct padata_instance, kobj)
879#define attr2pentry(_attr) \
880 container_of(_attr, struct padata_sysfs_entry, attr)
881
882static void padata_sysfs_release(struct kobject *kobj)
883{
884 struct padata_instance *pinst = kobj2pinst(kobj);
885 __padata_free(pinst);
886}
887
888struct padata_sysfs_entry {
889 struct attribute attr;
890 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
891 ssize_t (*store)(struct padata_instance *, struct attribute *,
892 const char *, size_t);
893};
894
895static ssize_t show_cpumask(struct padata_instance *pinst,
896 struct attribute *attr, char *buf)
897{
898 struct cpumask *cpumask;
899 ssize_t len;
900
901 mutex_lock(&pinst->lock);
902 if (!strcmp(attr->name, "serial_cpumask"))
903 cpumask = pinst->cpumask.cbcpu;
904 else
905 cpumask = pinst->cpumask.pcpu;
906
907 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
908 nr_cpu_ids, cpumask_bits(cpumask));
909 mutex_unlock(&pinst->lock);
910 return len < PAGE_SIZE ? len : -EINVAL;
911}
912
913static ssize_t store_cpumask(struct padata_instance *pinst,
914 struct attribute *attr,
915 const char *buf, size_t count)
916{
917 cpumask_var_t new_cpumask;
918 ssize_t ret;
919 int mask_type;
920
921 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
922 return -ENOMEM;
923
924 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
925 nr_cpumask_bits);
926 if (ret < 0)
927 goto out;
928
929 mask_type = !strcmp(attr->name, "serial_cpumask") ?
930 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
931 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
932 if (!ret)
933 ret = count;
934
935out:
936 free_cpumask_var(new_cpumask);
937 return ret;
938}
939
940#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
941 static struct padata_sysfs_entry _name##_attr = \
942 __ATTR(_name, 0644, _show_name, _store_name)
943#define PADATA_ATTR_RO(_name, _show_name) \
944 static struct padata_sysfs_entry _name##_attr = \
945 __ATTR(_name, 0400, _show_name, NULL)
946
947PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
948PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
949
950/*
951 * Padata sysfs provides the following objects:
952 * serial_cpumask [RW] - cpumask for serial workers
953 * parallel_cpumask [RW] - cpumask for parallel workers
954 */
955static struct attribute *padata_default_attrs[] = {
956 &serial_cpumask_attr.attr,
957 ¶llel_cpumask_attr.attr,
958 NULL,
959};
960
961static ssize_t padata_sysfs_show(struct kobject *kobj,
962 struct attribute *attr, char *buf)
963{
964 struct padata_instance *pinst;
965 struct padata_sysfs_entry *pentry;
966 ssize_t ret = -EIO;
967
968 pinst = kobj2pinst(kobj);
969 pentry = attr2pentry(attr);
970 if (pentry->show)
971 ret = pentry->show(pinst, attr, buf);
972
973 return ret;
974}
975
976static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
977 const char *buf, size_t count)
978{
979 struct padata_instance *pinst;
980 struct padata_sysfs_entry *pentry;
981 ssize_t ret = -EIO;
982
983 pinst = kobj2pinst(kobj);
984 pentry = attr2pentry(attr);
985 if (pentry->show)
986 ret = pentry->store(pinst, attr, buf, count);
987
988 return ret;
989}
990
991static const struct sysfs_ops padata_sysfs_ops = {
992 .show = padata_sysfs_show,
993 .store = padata_sysfs_store,
994};
995
996static struct kobj_type padata_attr_type = {
997 .sysfs_ops = &padata_sysfs_ops,
998 .default_attrs = padata_default_attrs,
999 .release = padata_sysfs_release,
1000};
1001
1002/**
1003 * padata_alloc - allocate and initialize a padata instance and specify
1004 * cpumasks for serial and parallel workers.
1005 *
1006 * @wq: workqueue to use for the allocated padata instance
1007 * @pcpumask: cpumask that will be used for padata parallelization
1008 * @cbcpumask: cpumask that will be used for padata serialization
1009 *
1010 * Must be called from a cpus_read_lock() protected region
1011 */
1012static struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1013 const struct cpumask *pcpumask,
1014 const struct cpumask *cbcpumask)
1015{
1016 struct padata_instance *pinst;
1017 struct parallel_data *pd = NULL;
1018
1019 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1020 if (!pinst)
1021 goto err;
1022
1023 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1024 goto err_free_inst;
1025 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1026 free_cpumask_var(pinst->cpumask.pcpu);
1027 goto err_free_inst;
1028 }
1029 if (!padata_validate_cpumask(pinst, pcpumask) ||
1030 !padata_validate_cpumask(pinst, cbcpumask))
1031 goto err_free_masks;
1032
1033 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1034 if (!pd)
1035 goto err_free_masks;
1036
1037 rcu_assign_pointer(pinst->pd, pd);
1038
1039 pinst->wq = wq;
1040
1041 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1042 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1043
1044 pinst->flags = 0;
1045
1046 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1047 kobject_init(&pinst->kobj, &padata_attr_type);
1048 mutex_init(&pinst->lock);
1049
1050#ifdef CONFIG_HOTPLUG_CPU
1051 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
1052#endif
1053 return pinst;
1054
1055err_free_masks:
1056 free_cpumask_var(pinst->cpumask.pcpu);
1057 free_cpumask_var(pinst->cpumask.cbcpu);
1058err_free_inst:
1059 kfree(pinst);
1060err:
1061 return NULL;
1062}
1063
1064/**
1065 * padata_alloc_possible - Allocate and initialize padata instance.
1066 * Use the cpu_possible_mask for serial and
1067 * parallel workers.
1068 *
1069 * @wq: workqueue to use for the allocated padata instance
1070 *
1071 * Must be called from a cpus_read_lock() protected region
1072 */
1073struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1074{
1075 lockdep_assert_cpus_held();
1076 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1077}
1078EXPORT_SYMBOL(padata_alloc_possible);
1079
1080/**
1081 * padata_free - free a padata instance
1082 *
1083 * @padata_inst: padata instance to free
1084 */
1085void padata_free(struct padata_instance *pinst)
1086{
1087 kobject_put(&pinst->kobj);
1088}
1089EXPORT_SYMBOL(padata_free);
1090
1091#ifdef CONFIG_HOTPLUG_CPU
1092
1093static __init int padata_driver_init(void)
1094{
1095 int ret;
1096
1097 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1098 padata_cpu_online,
1099 padata_cpu_prep_down);
1100 if (ret < 0)
1101 return ret;
1102 hp_online = ret;
1103 return 0;
1104}
1105module_init(padata_driver_init);
1106
1107static __exit void padata_driver_exit(void)
1108{
1109 cpuhp_remove_multi_state(hp_online);
1110}
1111module_exit(padata_driver_exit);
1112#endif