projects/linux·blob v4.9-rc1 · refs

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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 <[email protected]>
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
37static 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
48static 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
64static 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 */
107int 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
146out:
147 rcu_read_unlock_bh();
148
149 return err;
150}
151EXPORT_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 */
170static 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);
213out:
214 return padata;
215}
216
217static 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
286static void padata_reorder_timer(unsigned long arg)
287{
288 struct parallel_data *pd = (struct parallel_data *)arg;
289
290 padata_reorder(pd);
291}
292
293static 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 */
329void 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}
349EXPORT_SYMBOL(padata_do_serial);
350
351static 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
368static 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 */
375static 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 */
389static 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. */
409static 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
440err_free_squeue:
441 free_percpu(pd->squeue);
442err_free_pqueue:
443 free_percpu(pd->pqueue);
444err_free_pd:
445 kfree(pd);
446err:
447 return NULL;
448}
449
450static 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. */
460static 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
484static void __padata_start(struct padata_instance *pinst)
485{
486 pinst->flags |= PADATA_INIT;
487}
488
489static 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. */
504static 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 */
539int 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}
545EXPORT_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 */
554int 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}
561EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
562
563
564/* If cpumask contains no active cpu, we mark the instance as invalid. */
565static 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
577static 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
594out_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 */
619int 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
643out:
644 put_online_cpus();
645 mutex_unlock(&pinst->lock);
646
647 return err;
648}
649EXPORT_SYMBOL(padata_set_cpumask);
650
651/**
652 * padata_start - start the parallel processing
653 *
654 * @pinst: padata instance to start
655 */
656int 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}
671EXPORT_SYMBOL(padata_start);
672
673/**
674 * padata_stop - stop the parallel processing
675 *
676 * @pinst: padata instance to stop
677 */
678void padata_stop(struct padata_instance *pinst)
679{
680 mutex_lock(&pinst->lock);
681 __padata_stop(pinst);
682 mutex_unlock(&pinst->lock);
683}
684EXPORT_SYMBOL(padata_stop);
685
686#ifdef CONFIG_HOTPLUG_CPU
687
688static 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
708static 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 */
743int 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}
765EXPORT_SYMBOL(padata_remove_cpu);
766
767static 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
773static 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
788static 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
803static enum cpuhp_state hp_online;
804#endif
805
806static 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
824static void padata_sysfs_release(struct kobject *kobj)
825{
826 struct padata_instance *pinst = kobj2pinst(kobj);
827 __padata_free(pinst);
828}
829
830struct 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
837static 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
855static 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
877out:
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
889PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
890PADATA_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 */
897static struct attribute *padata_default_attrs[] = {
898 &serial_cpumask_attr.attr,
899 &parallel_cpumask_attr.attr,
900 NULL,
901};
902
903static 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
918static 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
933static const struct sysfs_ops padata_sysfs_ops = {
934 .show = padata_sysfs_show,
935 .store = padata_sysfs_store,
936};
937
938static 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 */
951struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
952{
953 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
954}
955EXPORT_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 */
965struct 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
1011err_free_masks:
1012 free_cpumask_var(pinst->cpumask.pcpu);
1013 free_cpumask_var(pinst->cpumask.cbcpu);
1014err_free_inst:
1015 kfree(pinst);
1016 put_online_cpus();
1017err:
1018 return NULL;
1019}
1020
1021/**
1022 * padata_free - free a padata instance
1023 *
1024 * @padata_inst: padata instance to free
1025 */
1026void padata_free(struct padata_instance *pinst)
1027{
1028 kobject_put(&pinst->kobj);
1029}
1030EXPORT_SYMBOL(padata_free);
1031
1032#ifdef CONFIG_HOTPLUG_CPU
1033
1034static __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}
1046module_init(padata_driver_init);
1047
1048static __exit void padata_driver_exit(void)
1049{
1050 cpuhp_remove_multi_state(hp_online);
1051}
1052module_exit(padata_driver_exit);
1053#endif