projects/linux·blob v3.18-rc3 · 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
34#define MAX_OBJ_NUM 1000
35
36static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
37{
38 int cpu, target_cpu;
39
40 target_cpu = cpumask_first(pd->cpumask.pcpu);
41 for (cpu = 0; cpu < cpu_index; cpu++)
42 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
43
44 return target_cpu;
45}
46
47static int padata_cpu_hash(struct parallel_data *pd)
48{
49 unsigned int seq_nr;
50 int cpu_index;
51
52 /*
53 * Hash the sequence numbers to the cpus by taking
54 * seq_nr mod. number of cpus in use.
55 */
56
57 seq_nr = atomic_inc_return(&pd->seq_nr);
58 cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
59
60 return padata_index_to_cpu(pd, cpu_index);
61}
62
63static void padata_parallel_worker(struct work_struct *parallel_work)
64{
65 struct padata_parallel_queue *pqueue;
66 struct parallel_data *pd;
67 struct padata_instance *pinst;
68 LIST_HEAD(local_list);
69
70 local_bh_disable();
71 pqueue = container_of(parallel_work,
72 struct padata_parallel_queue, work);
73 pd = pqueue->pd;
74 pinst = pd->pinst;
75
76 spin_lock(&pqueue->parallel.lock);
77 list_replace_init(&pqueue->parallel.list, &local_list);
78 spin_unlock(&pqueue->parallel.lock);
79
80 while (!list_empty(&local_list)) {
81 struct padata_priv *padata;
82
83 padata = list_entry(local_list.next,
84 struct padata_priv, list);
85
86 list_del_init(&padata->list);
87
88 padata->parallel(padata);
89 }
90
91 local_bh_enable();
92}
93
94/**
95 * padata_do_parallel - padata parallelization function
96 *
97 * @pinst: padata instance
98 * @padata: object to be parallelized
99 * @cb_cpu: cpu the serialization callback function will run on,
100 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
101 *
102 * The parallelization callback function will run with BHs off.
103 * Note: Every object which is parallelized by padata_do_parallel
104 * must be seen by padata_do_serial.
105 */
106int padata_do_parallel(struct padata_instance *pinst,
107 struct padata_priv *padata, int cb_cpu)
108{
109 int target_cpu, err;
110 struct padata_parallel_queue *queue;
111 struct parallel_data *pd;
112
113 rcu_read_lock_bh();
114
115 pd = rcu_dereference_bh(pinst->pd);
116
117 err = -EINVAL;
118 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
119 goto out;
120
121 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
122 goto out;
123
124 err = -EBUSY;
125 if ((pinst->flags & PADATA_RESET))
126 goto out;
127
128 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
129 goto out;
130
131 err = 0;
132 atomic_inc(&pd->refcnt);
133 padata->pd = pd;
134 padata->cb_cpu = cb_cpu;
135
136 target_cpu = padata_cpu_hash(pd);
137 queue = per_cpu_ptr(pd->pqueue, target_cpu);
138
139 spin_lock(&queue->parallel.lock);
140 list_add_tail(&padata->list, &queue->parallel.list);
141 spin_unlock(&queue->parallel.lock);
142
143 queue_work_on(target_cpu, pinst->wq, &queue->work);
144
145out:
146 rcu_read_unlock_bh();
147
148 return err;
149}
150EXPORT_SYMBOL(padata_do_parallel);
151
152/*
153 * padata_get_next - Get the next object that needs serialization.
154 *
155 * Return values are:
156 *
157 * A pointer to the control struct of the next object that needs
158 * serialization, if present in one of the percpu reorder queues.
159 *
160 * NULL, if all percpu reorder queues are empty.
161 *
162 * -EINPROGRESS, if the next object that needs serialization will
163 * be parallel processed by another cpu and is not yet present in
164 * the cpu's reorder queue.
165 *
166 * -ENODATA, if this cpu has to do the parallel processing for
167 * the next object.
168 */
169static struct padata_priv *padata_get_next(struct parallel_data *pd)
170{
171 int cpu, num_cpus;
172 unsigned int next_nr, next_index;
173 struct padata_parallel_queue *next_queue;
174 struct padata_priv *padata;
175 struct padata_list *reorder;
176
177 num_cpus = cpumask_weight(pd->cpumask.pcpu);
178
179 /*
180 * Calculate the percpu reorder queue and the sequence
181 * number of the next object.
182 */
183 next_nr = pd->processed;
184 next_index = next_nr % num_cpus;
185 cpu = padata_index_to_cpu(pd, next_index);
186 next_queue = per_cpu_ptr(pd->pqueue, cpu);
187
188 padata = NULL;
189
190 reorder = &next_queue->reorder;
191
192 if (!list_empty(&reorder->list)) {
193 padata = list_entry(reorder->list.next,
194 struct padata_priv, list);
195
196 spin_lock(&reorder->lock);
197 list_del_init(&padata->list);
198 atomic_dec(&pd->reorder_objects);
199 spin_unlock(&reorder->lock);
200
201 pd->processed++;
202
203 goto out;
204 }
205
206 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
207 padata = ERR_PTR(-ENODATA);
208 goto out;
209 }
210
211 padata = ERR_PTR(-EINPROGRESS);
212out:
213 return padata;
214}
215
216static void padata_reorder(struct parallel_data *pd)
217{
218 int cb_cpu;
219 struct padata_priv *padata;
220 struct padata_serial_queue *squeue;
221 struct padata_instance *pinst = pd->pinst;
222
223 /*
224 * We need to ensure that only one cpu can work on dequeueing of
225 * the reorder queue the time. Calculating in which percpu reorder
226 * queue the next object will arrive takes some time. A spinlock
227 * would be highly contended. Also it is not clear in which order
228 * the objects arrive to the reorder queues. So a cpu could wait to
229 * get the lock just to notice that there is nothing to do at the
230 * moment. Therefore we use a trylock and let the holder of the lock
231 * care for all the objects enqueued during the holdtime of the lock.
232 */
233 if (!spin_trylock_bh(&pd->lock))
234 return;
235
236 while (1) {
237 padata = padata_get_next(pd);
238
239 /*
240 * All reorder queues are empty, or the next object that needs
241 * serialization is parallel processed by another cpu and is
242 * still on it's way to the cpu's reorder queue, nothing to
243 * do for now.
244 */
245 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
246 break;
247
248 /*
249 * This cpu has to do the parallel processing of the next
250 * object. It's waiting in the cpu's parallelization queue,
251 * so exit immediately.
252 */
253 if (PTR_ERR(padata) == -ENODATA) {
254 del_timer(&pd->timer);
255 spin_unlock_bh(&pd->lock);
256 return;
257 }
258
259 cb_cpu = padata->cb_cpu;
260 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
261
262 spin_lock(&squeue->serial.lock);
263 list_add_tail(&padata->list, &squeue->serial.list);
264 spin_unlock(&squeue->serial.lock);
265
266 queue_work_on(cb_cpu, pinst->wq, &squeue->work);
267 }
268
269 spin_unlock_bh(&pd->lock);
270
271 /*
272 * The next object that needs serialization might have arrived to
273 * the reorder queues in the meantime, we will be called again
274 * from the timer function if no one else cares for it.
275 */
276 if (atomic_read(&pd->reorder_objects)
277 && !(pinst->flags & PADATA_RESET))
278 mod_timer(&pd->timer, jiffies + HZ);
279 else
280 del_timer(&pd->timer);
281
282 return;
283}
284
285static void padata_reorder_timer(unsigned long arg)
286{
287 struct parallel_data *pd = (struct parallel_data *)arg;
288
289 padata_reorder(pd);
290}
291
292static void padata_serial_worker(struct work_struct *serial_work)
293{
294 struct padata_serial_queue *squeue;
295 struct parallel_data *pd;
296 LIST_HEAD(local_list);
297
298 local_bh_disable();
299 squeue = container_of(serial_work, struct padata_serial_queue, work);
300 pd = squeue->pd;
301
302 spin_lock(&squeue->serial.lock);
303 list_replace_init(&squeue->serial.list, &local_list);
304 spin_unlock(&squeue->serial.lock);
305
306 while (!list_empty(&local_list)) {
307 struct padata_priv *padata;
308
309 padata = list_entry(local_list.next,
310 struct padata_priv, list);
311
312 list_del_init(&padata->list);
313
314 padata->serial(padata);
315 atomic_dec(&pd->refcnt);
316 }
317 local_bh_enable();
318}
319
320/**
321 * padata_do_serial - padata serialization function
322 *
323 * @padata: object to be serialized.
324 *
325 * padata_do_serial must be called for every parallelized object.
326 * The serialization callback function will run with BHs off.
327 */
328void padata_do_serial(struct padata_priv *padata)
329{
330 int cpu;
331 struct padata_parallel_queue *pqueue;
332 struct parallel_data *pd;
333
334 pd = padata->pd;
335
336 cpu = get_cpu();
337 pqueue = per_cpu_ptr(pd->pqueue, cpu);
338
339 spin_lock(&pqueue->reorder.lock);
340 atomic_inc(&pd->reorder_objects);
341 list_add_tail(&padata->list, &pqueue->reorder.list);
342 spin_unlock(&pqueue->reorder.lock);
343
344 put_cpu();
345
346 padata_reorder(pd);
347}
348EXPORT_SYMBOL(padata_do_serial);
349
350static int padata_setup_cpumasks(struct parallel_data *pd,
351 const struct cpumask *pcpumask,
352 const struct cpumask *cbcpumask)
353{
354 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
355 return -ENOMEM;
356
357 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
358 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
359 free_cpumask_var(pd->cpumask.cbcpu);
360 return -ENOMEM;
361 }
362
363 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
364 return 0;
365}
366
367static void __padata_list_init(struct padata_list *pd_list)
368{
369 INIT_LIST_HEAD(&pd_list->list);
370 spin_lock_init(&pd_list->lock);
371}
372
373/* Initialize all percpu queues used by serial workers */
374static void padata_init_squeues(struct parallel_data *pd)
375{
376 int cpu;
377 struct padata_serial_queue *squeue;
378
379 for_each_cpu(cpu, pd->cpumask.cbcpu) {
380 squeue = per_cpu_ptr(pd->squeue, cpu);
381 squeue->pd = pd;
382 __padata_list_init(&squeue->serial);
383 INIT_WORK(&squeue->work, padata_serial_worker);
384 }
385}
386
387/* Initialize all percpu queues used by parallel workers */
388static void padata_init_pqueues(struct parallel_data *pd)
389{
390 int cpu_index, cpu;
391 struct padata_parallel_queue *pqueue;
392
393 cpu_index = 0;
394 for_each_cpu(cpu, pd->cpumask.pcpu) {
395 pqueue = per_cpu_ptr(pd->pqueue, cpu);
396 pqueue->pd = pd;
397 pqueue->cpu_index = cpu_index;
398 cpu_index++;
399
400 __padata_list_init(&pqueue->reorder);
401 __padata_list_init(&pqueue->parallel);
402 INIT_WORK(&pqueue->work, padata_parallel_worker);
403 atomic_set(&pqueue->num_obj, 0);
404 }
405}
406
407/* Allocate and initialize the internal cpumask dependend resources. */
408static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
409 const struct cpumask *pcpumask,
410 const struct cpumask *cbcpumask)
411{
412 struct parallel_data *pd;
413
414 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
415 if (!pd)
416 goto err;
417
418 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
419 if (!pd->pqueue)
420 goto err_free_pd;
421
422 pd->squeue = alloc_percpu(struct padata_serial_queue);
423 if (!pd->squeue)
424 goto err_free_pqueue;
425 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
426 goto err_free_squeue;
427
428 padata_init_pqueues(pd);
429 padata_init_squeues(pd);
430 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
431 atomic_set(&pd->seq_nr, -1);
432 atomic_set(&pd->reorder_objects, 0);
433 atomic_set(&pd->refcnt, 0);
434 pd->pinst = pinst;
435 spin_lock_init(&pd->lock);
436
437 return pd;
438
439err_free_squeue:
440 free_percpu(pd->squeue);
441err_free_pqueue:
442 free_percpu(pd->pqueue);
443err_free_pd:
444 kfree(pd);
445err:
446 return NULL;
447}
448
449static void padata_free_pd(struct parallel_data *pd)
450{
451 free_cpumask_var(pd->cpumask.pcpu);
452 free_cpumask_var(pd->cpumask.cbcpu);
453 free_percpu(pd->pqueue);
454 free_percpu(pd->squeue);
455 kfree(pd);
456}
457
458/* Flush all objects out of the padata queues. */
459static void padata_flush_queues(struct parallel_data *pd)
460{
461 int cpu;
462 struct padata_parallel_queue *pqueue;
463 struct padata_serial_queue *squeue;
464
465 for_each_cpu(cpu, pd->cpumask.pcpu) {
466 pqueue = per_cpu_ptr(pd->pqueue, cpu);
467 flush_work(&pqueue->work);
468 }
469
470 del_timer_sync(&pd->timer);
471
472 if (atomic_read(&pd->reorder_objects))
473 padata_reorder(pd);
474
475 for_each_cpu(cpu, pd->cpumask.cbcpu) {
476 squeue = per_cpu_ptr(pd->squeue, cpu);
477 flush_work(&squeue->work);
478 }
479
480 BUG_ON(atomic_read(&pd->refcnt) != 0);
481}
482
483static void __padata_start(struct padata_instance *pinst)
484{
485 pinst->flags |= PADATA_INIT;
486}
487
488static void __padata_stop(struct padata_instance *pinst)
489{
490 if (!(pinst->flags & PADATA_INIT))
491 return;
492
493 pinst->flags &= ~PADATA_INIT;
494
495 synchronize_rcu();
496
497 get_online_cpus();
498 padata_flush_queues(pinst->pd);
499 put_online_cpus();
500}
501
502/* Replace the internal control structure with a new one. */
503static void padata_replace(struct padata_instance *pinst,
504 struct parallel_data *pd_new)
505{
506 struct parallel_data *pd_old = pinst->pd;
507 int notification_mask = 0;
508
509 pinst->flags |= PADATA_RESET;
510
511 rcu_assign_pointer(pinst->pd, pd_new);
512
513 synchronize_rcu();
514
515 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
516 notification_mask |= PADATA_CPU_PARALLEL;
517 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
518 notification_mask |= PADATA_CPU_SERIAL;
519
520 padata_flush_queues(pd_old);
521 padata_free_pd(pd_old);
522
523 if (notification_mask)
524 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
525 notification_mask,
526 &pd_new->cpumask);
527
528 pinst->flags &= ~PADATA_RESET;
529}
530
531/**
532 * padata_register_cpumask_notifier - Registers a notifier that will be called
533 * if either pcpu or cbcpu or both cpumasks change.
534 *
535 * @pinst: A poineter to padata instance
536 * @nblock: A pointer to notifier block.
537 */
538int padata_register_cpumask_notifier(struct padata_instance *pinst,
539 struct notifier_block *nblock)
540{
541 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
542 nblock);
543}
544EXPORT_SYMBOL(padata_register_cpumask_notifier);
545
546/**
547 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
548 * registered earlier using padata_register_cpumask_notifier
549 *
550 * @pinst: A pointer to data instance.
551 * @nlock: A pointer to notifier block.
552 */
553int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
554 struct notifier_block *nblock)
555{
556 return blocking_notifier_chain_unregister(
557 &pinst->cpumask_change_notifier,
558 nblock);
559}
560EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
561
562
563/* If cpumask contains no active cpu, we mark the instance as invalid. */
564static bool padata_validate_cpumask(struct padata_instance *pinst,
565 const struct cpumask *cpumask)
566{
567 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
568 pinst->flags |= PADATA_INVALID;
569 return false;
570 }
571
572 pinst->flags &= ~PADATA_INVALID;
573 return true;
574}
575
576static int __padata_set_cpumasks(struct padata_instance *pinst,
577 cpumask_var_t pcpumask,
578 cpumask_var_t cbcpumask)
579{
580 int valid;
581 struct parallel_data *pd;
582
583 valid = padata_validate_cpumask(pinst, pcpumask);
584 if (!valid) {
585 __padata_stop(pinst);
586 goto out_replace;
587 }
588
589 valid = padata_validate_cpumask(pinst, cbcpumask);
590 if (!valid)
591 __padata_stop(pinst);
592
593out_replace:
594 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
595 if (!pd)
596 return -ENOMEM;
597
598 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
599 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
600
601 padata_replace(pinst, pd);
602
603 if (valid)
604 __padata_start(pinst);
605
606 return 0;
607}
608
609/**
610 * padata_set_cpumasks - Set both parallel and serial cpumasks. The first
611 * one is used by parallel workers and the second one
612 * by the wokers doing serialization.
613 *
614 * @pinst: padata instance
615 * @pcpumask: the cpumask to use for parallel workers
616 * @cbcpumask: the cpumsak to use for serial workers
617 */
618int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
619 cpumask_var_t cbcpumask)
620{
621 int err;
622
623 mutex_lock(&pinst->lock);
624 get_online_cpus();
625
626 err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
627
628 put_online_cpus();
629 mutex_unlock(&pinst->lock);
630
631 return err;
632
633}
634EXPORT_SYMBOL(padata_set_cpumasks);
635
636/**
637 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
638 * equivalent to @cpumask.
639 *
640 * @pinst: padata instance
641 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
642 * to parallel and serial cpumasks respectively.
643 * @cpumask: the cpumask to use
644 */
645int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
646 cpumask_var_t cpumask)
647{
648 struct cpumask *serial_mask, *parallel_mask;
649 int err = -EINVAL;
650
651 mutex_lock(&pinst->lock);
652 get_online_cpus();
653
654 switch (cpumask_type) {
655 case PADATA_CPU_PARALLEL:
656 serial_mask = pinst->cpumask.cbcpu;
657 parallel_mask = cpumask;
658 break;
659 case PADATA_CPU_SERIAL:
660 parallel_mask = pinst->cpumask.pcpu;
661 serial_mask = cpumask;
662 break;
663 default:
664 goto out;
665 }
666
667 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
668
669out:
670 put_online_cpus();
671 mutex_unlock(&pinst->lock);
672
673 return err;
674}
675EXPORT_SYMBOL(padata_set_cpumask);
676
677static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
678{
679 struct parallel_data *pd;
680
681 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
682 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
683 pinst->cpumask.cbcpu);
684 if (!pd)
685 return -ENOMEM;
686
687 padata_replace(pinst, pd);
688
689 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
690 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
691 __padata_start(pinst);
692 }
693
694 return 0;
695}
696
697 /**
698 * padata_add_cpu - add a cpu to one or both(parallel and serial)
699 * padata cpumasks.
700 *
701 * @pinst: padata instance
702 * @cpu: cpu to add
703 * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
704 * The @mask may be any combination of the following flags:
705 * PADATA_CPU_SERIAL - serial cpumask
706 * PADATA_CPU_PARALLEL - parallel cpumask
707 */
708
709int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask)
710{
711 int err;
712
713 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
714 return -EINVAL;
715
716 mutex_lock(&pinst->lock);
717
718 get_online_cpus();
719 if (mask & PADATA_CPU_SERIAL)
720 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu);
721 if (mask & PADATA_CPU_PARALLEL)
722 cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
723
724 err = __padata_add_cpu(pinst, cpu);
725 put_online_cpus();
726
727 mutex_unlock(&pinst->lock);
728
729 return err;
730}
731EXPORT_SYMBOL(padata_add_cpu);
732
733static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
734{
735 struct parallel_data *pd = NULL;
736
737 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
738
739 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
740 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
741 __padata_stop(pinst);
742
743 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
744 pinst->cpumask.cbcpu);
745 if (!pd)
746 return -ENOMEM;
747
748 padata_replace(pinst, pd);
749
750 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
751 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
752 }
753
754 return 0;
755}
756
757 /**
758 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
759 * padata cpumasks.
760 *
761 * @pinst: padata instance
762 * @cpu: cpu to remove
763 * @mask: bitmask specifying from which cpumask @cpu should be removed
764 * The @mask may be any combination of the following flags:
765 * PADATA_CPU_SERIAL - serial cpumask
766 * PADATA_CPU_PARALLEL - parallel cpumask
767 */
768int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
769{
770 int err;
771
772 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
773 return -EINVAL;
774
775 mutex_lock(&pinst->lock);
776
777 get_online_cpus();
778 if (mask & PADATA_CPU_SERIAL)
779 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
780 if (mask & PADATA_CPU_PARALLEL)
781 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
782
783 err = __padata_remove_cpu(pinst, cpu);
784 put_online_cpus();
785
786 mutex_unlock(&pinst->lock);
787
788 return err;
789}
790EXPORT_SYMBOL(padata_remove_cpu);
791
792/**
793 * padata_start - start the parallel processing
794 *
795 * @pinst: padata instance to start
796 */
797int padata_start(struct padata_instance *pinst)
798{
799 int err = 0;
800
801 mutex_lock(&pinst->lock);
802
803 if (pinst->flags & PADATA_INVALID)
804 err =-EINVAL;
805
806 __padata_start(pinst);
807
808 mutex_unlock(&pinst->lock);
809
810 return err;
811}
812EXPORT_SYMBOL(padata_start);
813
814/**
815 * padata_stop - stop the parallel processing
816 *
817 * @pinst: padata instance to stop
818 */
819void padata_stop(struct padata_instance *pinst)
820{
821 mutex_lock(&pinst->lock);
822 __padata_stop(pinst);
823 mutex_unlock(&pinst->lock);
824}
825EXPORT_SYMBOL(padata_stop);
826
827#ifdef CONFIG_HOTPLUG_CPU
828
829static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
830{
831 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
832 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
833}
834
835
836static int padata_cpu_callback(struct notifier_block *nfb,
837 unsigned long action, void *hcpu)
838{
839 int err;
840 struct padata_instance *pinst;
841 int cpu = (unsigned long)hcpu;
842
843 pinst = container_of(nfb, struct padata_instance, cpu_notifier);
844
845 switch (action) {
846 case CPU_ONLINE:
847 case CPU_ONLINE_FROZEN:
848 case CPU_DOWN_FAILED:
849 case CPU_DOWN_FAILED_FROZEN:
850 if (!pinst_has_cpu(pinst, cpu))
851 break;
852 mutex_lock(&pinst->lock);
853 err = __padata_add_cpu(pinst, cpu);
854 mutex_unlock(&pinst->lock);
855 if (err)
856 return notifier_from_errno(err);
857 break;
858
859 case CPU_DOWN_PREPARE:
860 case CPU_DOWN_PREPARE_FROZEN:
861 case CPU_UP_CANCELED:
862 case CPU_UP_CANCELED_FROZEN:
863 if (!pinst_has_cpu(pinst, cpu))
864 break;
865 mutex_lock(&pinst->lock);
866 err = __padata_remove_cpu(pinst, cpu);
867 mutex_unlock(&pinst->lock);
868 if (err)
869 return notifier_from_errno(err);
870 break;
871 }
872
873 return NOTIFY_OK;
874}
875#endif
876
877static void __padata_free(struct padata_instance *pinst)
878{
879#ifdef CONFIG_HOTPLUG_CPU
880 unregister_hotcpu_notifier(&pinst->cpu_notifier);
881#endif
882
883 padata_stop(pinst);
884 padata_free_pd(pinst->pd);
885 free_cpumask_var(pinst->cpumask.pcpu);
886 free_cpumask_var(pinst->cpumask.cbcpu);
887 kfree(pinst);
888}
889
890#define kobj2pinst(_kobj) \
891 container_of(_kobj, struct padata_instance, kobj)
892#define attr2pentry(_attr) \
893 container_of(_attr, struct padata_sysfs_entry, attr)
894
895static void padata_sysfs_release(struct kobject *kobj)
896{
897 struct padata_instance *pinst = kobj2pinst(kobj);
898 __padata_free(pinst);
899}
900
901struct padata_sysfs_entry {
902 struct attribute attr;
903 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
904 ssize_t (*store)(struct padata_instance *, struct attribute *,
905 const char *, size_t);
906};
907
908static ssize_t show_cpumask(struct padata_instance *pinst,
909 struct attribute *attr, char *buf)
910{
911 struct cpumask *cpumask;
912 ssize_t len;
913
914 mutex_lock(&pinst->lock);
915 if (!strcmp(attr->name, "serial_cpumask"))
916 cpumask = pinst->cpumask.cbcpu;
917 else
918 cpumask = pinst->cpumask.pcpu;
919
920 len = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask),
921 nr_cpu_ids);
922 if (PAGE_SIZE - len < 2)
923 len = -EINVAL;
924 else
925 len += sprintf(buf + len, "\n");
926
927 mutex_unlock(&pinst->lock);
928 return len;
929}
930
931static ssize_t store_cpumask(struct padata_instance *pinst,
932 struct attribute *attr,
933 const char *buf, size_t count)
934{
935 cpumask_var_t new_cpumask;
936 ssize_t ret;
937 int mask_type;
938
939 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
940 return -ENOMEM;
941
942 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
943 nr_cpumask_bits);
944 if (ret < 0)
945 goto out;
946
947 mask_type = !strcmp(attr->name, "serial_cpumask") ?
948 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
949 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
950 if (!ret)
951 ret = count;
952
953out:
954 free_cpumask_var(new_cpumask);
955 return ret;
956}
957
958#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
959 static struct padata_sysfs_entry _name##_attr = \
960 __ATTR(_name, 0644, _show_name, _store_name)
961#define PADATA_ATTR_RO(_name, _show_name) \
962 static struct padata_sysfs_entry _name##_attr = \
963 __ATTR(_name, 0400, _show_name, NULL)
964
965PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
966PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
967
968/*
969 * Padata sysfs provides the following objects:
970 * serial_cpumask [RW] - cpumask for serial workers
971 * parallel_cpumask [RW] - cpumask for parallel workers
972 */
973static struct attribute *padata_default_attrs[] = {
974 &serial_cpumask_attr.attr,
975 &parallel_cpumask_attr.attr,
976 NULL,
977};
978
979static ssize_t padata_sysfs_show(struct kobject *kobj,
980 struct attribute *attr, char *buf)
981{
982 struct padata_instance *pinst;
983 struct padata_sysfs_entry *pentry;
984 ssize_t ret = -EIO;
985
986 pinst = kobj2pinst(kobj);
987 pentry = attr2pentry(attr);
988 if (pentry->show)
989 ret = pentry->show(pinst, attr, buf);
990
991 return ret;
992}
993
994static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
995 const char *buf, size_t count)
996{
997 struct padata_instance *pinst;
998 struct padata_sysfs_entry *pentry;
999 ssize_t ret = -EIO;
1000
1001 pinst = kobj2pinst(kobj);
1002 pentry = attr2pentry(attr);
1003 if (pentry->show)
1004 ret = pentry->store(pinst, attr, buf, count);
1005
1006 return ret;
1007}
1008
1009static const struct sysfs_ops padata_sysfs_ops = {
1010 .show = padata_sysfs_show,
1011 .store = padata_sysfs_store,
1012};
1013
1014static struct kobj_type padata_attr_type = {
1015 .sysfs_ops = &padata_sysfs_ops,
1016 .default_attrs = padata_default_attrs,
1017 .release = padata_sysfs_release,
1018};
1019
1020/**
1021 * padata_alloc_possible - Allocate and initialize padata instance.
1022 * Use the cpu_possible_mask for serial and
1023 * parallel workers.
1024 *
1025 * @wq: workqueue to use for the allocated padata instance
1026 */
1027struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1028{
1029 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1030}
1031EXPORT_SYMBOL(padata_alloc_possible);
1032
1033/**
1034 * padata_alloc - allocate and initialize a padata instance and specify
1035 * cpumasks for serial and parallel workers.
1036 *
1037 * @wq: workqueue to use for the allocated padata instance
1038 * @pcpumask: cpumask that will be used for padata parallelization
1039 * @cbcpumask: cpumask that will be used for padata serialization
1040 */
1041struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1042 const struct cpumask *pcpumask,
1043 const struct cpumask *cbcpumask)
1044{
1045 struct padata_instance *pinst;
1046 struct parallel_data *pd = NULL;
1047
1048 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1049 if (!pinst)
1050 goto err;
1051
1052 get_online_cpus();
1053 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1054 goto err_free_inst;
1055 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1056 free_cpumask_var(pinst->cpumask.pcpu);
1057 goto err_free_inst;
1058 }
1059 if (!padata_validate_cpumask(pinst, pcpumask) ||
1060 !padata_validate_cpumask(pinst, cbcpumask))
1061 goto err_free_masks;
1062
1063 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1064 if (!pd)
1065 goto err_free_masks;
1066
1067 rcu_assign_pointer(pinst->pd, pd);
1068
1069 pinst->wq = wq;
1070
1071 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1072 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1073
1074 pinst->flags = 0;
1075
1076 put_online_cpus();
1077
1078 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1079 kobject_init(&pinst->kobj, &padata_attr_type);
1080 mutex_init(&pinst->lock);
1081
1082#ifdef CONFIG_HOTPLUG_CPU
1083 pinst->cpu_notifier.notifier_call = padata_cpu_callback;
1084 pinst->cpu_notifier.priority = 0;
1085 register_hotcpu_notifier(&pinst->cpu_notifier);
1086#endif
1087
1088 return pinst;
1089
1090err_free_masks:
1091 free_cpumask_var(pinst->cpumask.pcpu);
1092 free_cpumask_var(pinst->cpumask.cbcpu);
1093err_free_inst:
1094 kfree(pinst);
1095 put_online_cpus();
1096err:
1097 return NULL;
1098}
1099EXPORT_SYMBOL(padata_alloc);
1100
1101/**
1102 * padata_free - free a padata instance
1103 *
1104 * @padata_inst: padata instance to free
1105 */
1106void padata_free(struct padata_instance *pinst)
1107{
1108 kobject_put(&pinst->kobj);
1109}
1110EXPORT_SYMBOL(padata_free);