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