projects/linux·blob v3.10-rc2 · 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 int cpu_index;
50
51 /*
52 * Hash the sequence numbers to the cpus by taking
53 * seq_nr mod. number of cpus in use.
54 */
55
56 spin_lock(&pd->seq_lock);
57 cpu_index = pd->seq_nr % cpumask_weight(pd->cpumask.pcpu);
58 pd->seq_nr++;
59 spin_unlock(&pd->seq_lock);
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(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 pd->seq_nr = 0;
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_cpumasks - Set both parallel and serial cpumasks. The first
612 * one is used by parallel workers and the second one
613 * by the wokers doing serialization.
614 *
615 * @pinst: padata instance
616 * @pcpumask: the cpumask to use for parallel workers
617 * @cbcpumask: the cpumsak to use for serial workers
618 */
619int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
620 cpumask_var_t cbcpumask)
621{
622 int err;
623
624 mutex_lock(&pinst->lock);
625 get_online_cpus();
626
627 err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
628
629 put_online_cpus();
630 mutex_unlock(&pinst->lock);
631
632 return err;
633
634}
635EXPORT_SYMBOL(padata_set_cpumasks);
636
637/**
638 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
639 * equivalent to @cpumask.
640 *
641 * @pinst: padata instance
642 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
643 * to parallel and serial cpumasks respectively.
644 * @cpumask: the cpumask to use
645 */
646int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
647 cpumask_var_t cpumask)
648{
649 struct cpumask *serial_mask, *parallel_mask;
650 int err = -EINVAL;
651
652 mutex_lock(&pinst->lock);
653 get_online_cpus();
654
655 switch (cpumask_type) {
656 case PADATA_CPU_PARALLEL:
657 serial_mask = pinst->cpumask.cbcpu;
658 parallel_mask = cpumask;
659 break;
660 case PADATA_CPU_SERIAL:
661 parallel_mask = pinst->cpumask.pcpu;
662 serial_mask = cpumask;
663 break;
664 default:
665 goto out;
666 }
667
668 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
669
670out:
671 put_online_cpus();
672 mutex_unlock(&pinst->lock);
673
674 return err;
675}
676EXPORT_SYMBOL(padata_set_cpumask);
677
678static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
679{
680 struct parallel_data *pd;
681
682 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
683 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
684 pinst->cpumask.cbcpu);
685 if (!pd)
686 return -ENOMEM;
687
688 padata_replace(pinst, pd);
689
690 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
691 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
692 __padata_start(pinst);
693 }
694
695 return 0;
696}
697
698 /**
699 * padata_add_cpu - add a cpu to one or both(parallel and serial)
700 * padata cpumasks.
701 *
702 * @pinst: padata instance
703 * @cpu: cpu to add
704 * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
705 * The @mask may be any combination of the following flags:
706 * PADATA_CPU_SERIAL - serial cpumask
707 * PADATA_CPU_PARALLEL - parallel cpumask
708 */
709
710int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask)
711{
712 int err;
713
714 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
715 return -EINVAL;
716
717 mutex_lock(&pinst->lock);
718
719 get_online_cpus();
720 if (mask & PADATA_CPU_SERIAL)
721 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu);
722 if (mask & PADATA_CPU_PARALLEL)
723 cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
724
725 err = __padata_add_cpu(pinst, cpu);
726 put_online_cpus();
727
728 mutex_unlock(&pinst->lock);
729
730 return err;
731}
732EXPORT_SYMBOL(padata_add_cpu);
733
734static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
735{
736 struct parallel_data *pd = NULL;
737
738 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
739
740 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
741 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
742 __padata_stop(pinst);
743
744 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
745 pinst->cpumask.cbcpu);
746 if (!pd)
747 return -ENOMEM;
748
749 padata_replace(pinst, pd);
750
751 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
752 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
753 }
754
755 return 0;
756}
757
758 /**
759 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
760 * padata cpumasks.
761 *
762 * @pinst: padata instance
763 * @cpu: cpu to remove
764 * @mask: bitmask specifying from which cpumask @cpu should be removed
765 * The @mask may be any combination of the following flags:
766 * PADATA_CPU_SERIAL - serial cpumask
767 * PADATA_CPU_PARALLEL - parallel cpumask
768 */
769int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
770{
771 int err;
772
773 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
774 return -EINVAL;
775
776 mutex_lock(&pinst->lock);
777
778 get_online_cpus();
779 if (mask & PADATA_CPU_SERIAL)
780 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
781 if (mask & PADATA_CPU_PARALLEL)
782 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
783
784 err = __padata_remove_cpu(pinst, cpu);
785 put_online_cpus();
786
787 mutex_unlock(&pinst->lock);
788
789 return err;
790}
791EXPORT_SYMBOL(padata_remove_cpu);
792
793/**
794 * padata_start - start the parallel processing
795 *
796 * @pinst: padata instance to start
797 */
798int padata_start(struct padata_instance *pinst)
799{
800 int err = 0;
801
802 mutex_lock(&pinst->lock);
803
804 if (pinst->flags & PADATA_INVALID)
805 err =-EINVAL;
806
807 __padata_start(pinst);
808
809 mutex_unlock(&pinst->lock);
810
811 return err;
812}
813EXPORT_SYMBOL(padata_start);
814
815/**
816 * padata_stop - stop the parallel processing
817 *
818 * @pinst: padata instance to stop
819 */
820void padata_stop(struct padata_instance *pinst)
821{
822 mutex_lock(&pinst->lock);
823 __padata_stop(pinst);
824 mutex_unlock(&pinst->lock);
825}
826EXPORT_SYMBOL(padata_stop);
827
828#ifdef CONFIG_HOTPLUG_CPU
829
830static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
831{
832 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
833 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
834}
835
836
837static int padata_cpu_callback(struct notifier_block *nfb,
838 unsigned long action, void *hcpu)
839{
840 int err;
841 struct padata_instance *pinst;
842 int cpu = (unsigned long)hcpu;
843
844 pinst = container_of(nfb, struct padata_instance, cpu_notifier);
845
846 switch (action) {
847 case CPU_ONLINE:
848 case CPU_ONLINE_FROZEN:
849 if (!pinst_has_cpu(pinst, cpu))
850 break;
851 mutex_lock(&pinst->lock);
852 err = __padata_add_cpu(pinst, cpu);
853 mutex_unlock(&pinst->lock);
854 if (err)
855 return notifier_from_errno(err);
856 break;
857
858 case CPU_DOWN_PREPARE:
859 case CPU_DOWN_PREPARE_FROZEN:
860 if (!pinst_has_cpu(pinst, cpu))
861 break;
862 mutex_lock(&pinst->lock);
863 err = __padata_remove_cpu(pinst, cpu);
864 mutex_unlock(&pinst->lock);
865 if (err)
866 return notifier_from_errno(err);
867 break;
868
869 case CPU_UP_CANCELED:
870 case CPU_UP_CANCELED_FROZEN:
871 if (!pinst_has_cpu(pinst, cpu))
872 break;
873 mutex_lock(&pinst->lock);
874 __padata_remove_cpu(pinst, cpu);
875 mutex_unlock(&pinst->lock);
876
877 case CPU_DOWN_FAILED:
878 case CPU_DOWN_FAILED_FROZEN:
879 if (!pinst_has_cpu(pinst, cpu))
880 break;
881 mutex_lock(&pinst->lock);
882 __padata_add_cpu(pinst, cpu);
883 mutex_unlock(&pinst->lock);
884 }
885
886 return NOTIFY_OK;
887}
888#endif
889
890static void __padata_free(struct padata_instance *pinst)
891{
892#ifdef CONFIG_HOTPLUG_CPU
893 unregister_hotcpu_notifier(&pinst->cpu_notifier);
894#endif
895
896 padata_stop(pinst);
897 padata_free_pd(pinst->pd);
898 free_cpumask_var(pinst->cpumask.pcpu);
899 free_cpumask_var(pinst->cpumask.cbcpu);
900 kfree(pinst);
901}
902
903#define kobj2pinst(_kobj) \
904 container_of(_kobj, struct padata_instance, kobj)
905#define attr2pentry(_attr) \
906 container_of(_attr, struct padata_sysfs_entry, attr)
907
908static void padata_sysfs_release(struct kobject *kobj)
909{
910 struct padata_instance *pinst = kobj2pinst(kobj);
911 __padata_free(pinst);
912}
913
914struct padata_sysfs_entry {
915 struct attribute attr;
916 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
917 ssize_t (*store)(struct padata_instance *, struct attribute *,
918 const char *, size_t);
919};
920
921static ssize_t show_cpumask(struct padata_instance *pinst,
922 struct attribute *attr, char *buf)
923{
924 struct cpumask *cpumask;
925 ssize_t len;
926
927 mutex_lock(&pinst->lock);
928 if (!strcmp(attr->name, "serial_cpumask"))
929 cpumask = pinst->cpumask.cbcpu;
930 else
931 cpumask = pinst->cpumask.pcpu;
932
933 len = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask),
934 nr_cpu_ids);
935 if (PAGE_SIZE - len < 2)
936 len = -EINVAL;
937 else
938 len += sprintf(buf + len, "\n");
939
940 mutex_unlock(&pinst->lock);
941 return len;
942}
943
944static ssize_t store_cpumask(struct padata_instance *pinst,
945 struct attribute *attr,
946 const char *buf, size_t count)
947{
948 cpumask_var_t new_cpumask;
949 ssize_t ret;
950 int mask_type;
951
952 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
953 return -ENOMEM;
954
955 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
956 nr_cpumask_bits);
957 if (ret < 0)
958 goto out;
959
960 mask_type = !strcmp(attr->name, "serial_cpumask") ?
961 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
962 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
963 if (!ret)
964 ret = count;
965
966out:
967 free_cpumask_var(new_cpumask);
968 return ret;
969}
970
971#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
972 static struct padata_sysfs_entry _name##_attr = \
973 __ATTR(_name, 0644, _show_name, _store_name)
974#define PADATA_ATTR_RO(_name, _show_name) \
975 static struct padata_sysfs_entry _name##_attr = \
976 __ATTR(_name, 0400, _show_name, NULL)
977
978PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
979PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
980
981/*
982 * Padata sysfs provides the following objects:
983 * serial_cpumask [RW] - cpumask for serial workers
984 * parallel_cpumask [RW] - cpumask for parallel workers
985 */
986static struct attribute *padata_default_attrs[] = {
987 &serial_cpumask_attr.attr,
988 &parallel_cpumask_attr.attr,
989 NULL,
990};
991
992static ssize_t padata_sysfs_show(struct kobject *kobj,
993 struct attribute *attr, char *buf)
994{
995 struct padata_instance *pinst;
996 struct padata_sysfs_entry *pentry;
997 ssize_t ret = -EIO;
998
999 pinst = kobj2pinst(kobj);
1000 pentry = attr2pentry(attr);
1001 if (pentry->show)
1002 ret = pentry->show(pinst, attr, buf);
1003
1004 return ret;
1005}
1006
1007static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
1008 const char *buf, size_t count)
1009{
1010 struct padata_instance *pinst;
1011 struct padata_sysfs_entry *pentry;
1012 ssize_t ret = -EIO;
1013
1014 pinst = kobj2pinst(kobj);
1015 pentry = attr2pentry(attr);
1016 if (pentry->show)
1017 ret = pentry->store(pinst, attr, buf, count);
1018
1019 return ret;
1020}
1021
1022static const struct sysfs_ops padata_sysfs_ops = {
1023 .show = padata_sysfs_show,
1024 .store = padata_sysfs_store,
1025};
1026
1027static struct kobj_type padata_attr_type = {
1028 .sysfs_ops = &padata_sysfs_ops,
1029 .default_attrs = padata_default_attrs,
1030 .release = padata_sysfs_release,
1031};
1032
1033/**
1034 * padata_alloc_possible - Allocate and initialize padata instance.
1035 * Use the cpu_possible_mask for serial and
1036 * parallel workers.
1037 *
1038 * @wq: workqueue to use for the allocated padata instance
1039 */
1040struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1041{
1042 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1043}
1044EXPORT_SYMBOL(padata_alloc_possible);
1045
1046/**
1047 * padata_alloc - allocate and initialize a padata instance and specify
1048 * cpumasks for serial and parallel workers.
1049 *
1050 * @wq: workqueue to use for the allocated padata instance
1051 * @pcpumask: cpumask that will be used for padata parallelization
1052 * @cbcpumask: cpumask that will be used for padata serialization
1053 */
1054struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1055 const struct cpumask *pcpumask,
1056 const struct cpumask *cbcpumask)
1057{
1058 struct padata_instance *pinst;
1059 struct parallel_data *pd = NULL;
1060
1061 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1062 if (!pinst)
1063 goto err;
1064
1065 get_online_cpus();
1066 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1067 goto err_free_inst;
1068 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1069 free_cpumask_var(pinst->cpumask.pcpu);
1070 goto err_free_inst;
1071 }
1072 if (!padata_validate_cpumask(pinst, pcpumask) ||
1073 !padata_validate_cpumask(pinst, cbcpumask))
1074 goto err_free_masks;
1075
1076 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1077 if (!pd)
1078 goto err_free_masks;
1079
1080 rcu_assign_pointer(pinst->pd, pd);
1081
1082 pinst->wq = wq;
1083
1084 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1085 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1086
1087 pinst->flags = 0;
1088
1089#ifdef CONFIG_HOTPLUG_CPU
1090 pinst->cpu_notifier.notifier_call = padata_cpu_callback;
1091 pinst->cpu_notifier.priority = 0;
1092 register_hotcpu_notifier(&pinst->cpu_notifier);
1093#endif
1094
1095 put_online_cpus();
1096
1097 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1098 kobject_init(&pinst->kobj, &padata_attr_type);
1099 mutex_init(&pinst->lock);
1100
1101 return pinst;
1102
1103err_free_masks:
1104 free_cpumask_var(pinst->cpumask.pcpu);
1105 free_cpumask_var(pinst->cpumask.cbcpu);
1106err_free_inst:
1107 kfree(pinst);
1108 put_online_cpus();
1109err:
1110 return NULL;
1111}
1112EXPORT_SYMBOL(padata_alloc);
1113
1114/**
1115 * padata_free - free a padata instance
1116 *
1117 * @padata_inst: padata instance to free
1118 */
1119void padata_free(struct padata_instance *pinst)
1120{
1121 kobject_put(&pinst->kobj);
1122}
1123EXPORT_SYMBOL(padata_free);