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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 <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
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 spin_lock(&reorder->lock);
194 if (!list_empty(&reorder->list)) {
195 padata = list_entry(reorder->list.next,
196 struct padata_priv, list);
197
198 list_del_init(&padata->list);
199 atomic_dec(&pd->reorder_objects);
200
201 pd->processed++;
202
203 spin_unlock(&reorder->lock);
204 goto out;
205 }
206 spin_unlock(&reorder->lock);
207
208 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
209 padata = ERR_PTR(-ENODATA);
210 goto out;
211 }
212
213 padata = ERR_PTR(-EINPROGRESS);
214out:
215 return padata;
216}
217
218static void padata_reorder(struct parallel_data *pd)
219{
220 int cb_cpu;
221 struct padata_priv *padata;
222 struct padata_serial_queue *squeue;
223 struct padata_instance *pinst = pd->pinst;
224
225 /*
226 * We need to ensure that only one cpu can work on dequeueing of
227 * the reorder queue the time. Calculating in which percpu reorder
228 * queue the next object will arrive takes some time. A spinlock
229 * would be highly contended. Also it is not clear in which order
230 * the objects arrive to the reorder queues. So a cpu could wait to
231 * get the lock just to notice that there is nothing to do at the
232 * moment. Therefore we use a trylock and let the holder of the lock
233 * care for all the objects enqueued during the holdtime of the lock.
234 */
235 if (!spin_trylock_bh(&pd->lock))
236 return;
237
238 while (1) {
239 padata = padata_get_next(pd);
240
241 /*
242 * All reorder queues are empty, or the next object that needs
243 * serialization is parallel processed by another cpu and is
244 * still on it's way to the cpu's reorder queue, nothing to
245 * do for now.
246 */
247 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
248 break;
249
250 /*
251 * This cpu has to do the parallel processing of the next
252 * object. It's waiting in the cpu's parallelization queue,
253 * so exit immediately.
254 */
255 if (PTR_ERR(padata) == -ENODATA) {
256 del_timer(&pd->timer);
257 spin_unlock_bh(&pd->lock);
258 return;
259 }
260
261 cb_cpu = padata->cb_cpu;
262 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
263
264 spin_lock(&squeue->serial.lock);
265 list_add_tail(&padata->list, &squeue->serial.list);
266 spin_unlock(&squeue->serial.lock);
267
268 queue_work_on(cb_cpu, pinst->wq, &squeue->work);
269 }
270
271 spin_unlock_bh(&pd->lock);
272
273 /*
274 * The next object that needs serialization might have arrived to
275 * the reorder queues in the meantime, we will be called again
276 * from the timer function if no one else cares for it.
277 */
278 if (atomic_read(&pd->reorder_objects)
279 && !(pinst->flags & PADATA_RESET))
280 mod_timer(&pd->timer, jiffies + HZ);
281 else
282 del_timer(&pd->timer);
283
284 return;
285}
286
287static void padata_reorder_timer(unsigned long arg)
288{
289 struct parallel_data *pd = (struct parallel_data *)arg;
290
291 padata_reorder(pd);
292}
293
294static void padata_serial_worker(struct work_struct *serial_work)
295{
296 struct padata_serial_queue *squeue;
297 struct parallel_data *pd;
298 LIST_HEAD(local_list);
299
300 local_bh_disable();
301 squeue = container_of(serial_work, struct padata_serial_queue, work);
302 pd = squeue->pd;
303
304 spin_lock(&squeue->serial.lock);
305 list_replace_init(&squeue->serial.list, &local_list);
306 spin_unlock(&squeue->serial.lock);
307
308 while (!list_empty(&local_list)) {
309 struct padata_priv *padata;
310
311 padata = list_entry(local_list.next,
312 struct padata_priv, list);
313
314 list_del_init(&padata->list);
315
316 padata->serial(padata);
317 atomic_dec(&pd->refcnt);
318 }
319 local_bh_enable();
320}
321
322/**
323 * padata_do_serial - padata serialization function
324 *
325 * @padata: object to be serialized.
326 *
327 * padata_do_serial must be called for every parallelized object.
328 * The serialization callback function will run with BHs off.
329 */
330void padata_do_serial(struct padata_priv *padata)
331{
332 int cpu;
333 struct padata_parallel_queue *pqueue;
334 struct parallel_data *pd;
335
336 pd = padata->pd;
337
338 cpu = get_cpu();
339 pqueue = per_cpu_ptr(pd->pqueue, cpu);
340
341 spin_lock(&pqueue->reorder.lock);
342 atomic_inc(&pd->reorder_objects);
343 list_add_tail(&padata->list, &pqueue->reorder.list);
344 spin_unlock(&pqueue->reorder.lock);
345
346 put_cpu();
347
348 padata_reorder(pd);
349}
350EXPORT_SYMBOL(padata_do_serial);
351
352static int padata_setup_cpumasks(struct parallel_data *pd,
353 const struct cpumask *pcpumask,
354 const struct cpumask *cbcpumask)
355{
356 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
357 return -ENOMEM;
358
359 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
360 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
361 free_cpumask_var(pd->cpumask.pcpu);
362 return -ENOMEM;
363 }
364
365 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
366 return 0;
367}
368
369static void __padata_list_init(struct padata_list *pd_list)
370{
371 INIT_LIST_HEAD(&pd_list->list);
372 spin_lock_init(&pd_list->lock);
373}
374
375/* Initialize all percpu queues used by serial workers */
376static void padata_init_squeues(struct parallel_data *pd)
377{
378 int cpu;
379 struct padata_serial_queue *squeue;
380
381 for_each_cpu(cpu, pd->cpumask.cbcpu) {
382 squeue = per_cpu_ptr(pd->squeue, cpu);
383 squeue->pd = pd;
384 __padata_list_init(&squeue->serial);
385 INIT_WORK(&squeue->work, padata_serial_worker);
386 }
387}
388
389/* Initialize all percpu queues used by parallel workers */
390static void padata_init_pqueues(struct parallel_data *pd)
391{
392 int cpu_index, cpu;
393 struct padata_parallel_queue *pqueue;
394
395 cpu_index = 0;
396 for_each_cpu(cpu, pd->cpumask.pcpu) {
397 pqueue = per_cpu_ptr(pd->pqueue, cpu);
398 pqueue->pd = pd;
399 pqueue->cpu_index = cpu_index;
400 cpu_index++;
401
402 __padata_list_init(&pqueue->reorder);
403 __padata_list_init(&pqueue->parallel);
404 INIT_WORK(&pqueue->work, padata_parallel_worker);
405 atomic_set(&pqueue->num_obj, 0);
406 }
407}
408
409/* Allocate and initialize the internal cpumask dependend resources. */
410static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
411 const struct cpumask *pcpumask,
412 const struct cpumask *cbcpumask)
413{
414 struct parallel_data *pd;
415
416 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
417 if (!pd)
418 goto err;
419
420 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
421 if (!pd->pqueue)
422 goto err_free_pd;
423
424 pd->squeue = alloc_percpu(struct padata_serial_queue);
425 if (!pd->squeue)
426 goto err_free_pqueue;
427 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
428 goto err_free_squeue;
429
430 padata_init_pqueues(pd);
431 padata_init_squeues(pd);
432 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
433 atomic_set(&pd->seq_nr, -1);
434 atomic_set(&pd->reorder_objects, 0);
435 atomic_set(&pd->refcnt, 0);
436 pd->pinst = pinst;
437 spin_lock_init(&pd->lock);
438
439 return pd;
440
441err_free_squeue:
442 free_percpu(pd->squeue);
443err_free_pqueue:
444 free_percpu(pd->pqueue);
445err_free_pd:
446 kfree(pd);
447err:
448 return NULL;
449}
450
451static void padata_free_pd(struct parallel_data *pd)
452{
453 free_cpumask_var(pd->cpumask.pcpu);
454 free_cpumask_var(pd->cpumask.cbcpu);
455 free_percpu(pd->pqueue);
456 free_percpu(pd->squeue);
457 kfree(pd);
458}
459
460/* Flush all objects out of the padata queues. */
461static void padata_flush_queues(struct parallel_data *pd)
462{
463 int cpu;
464 struct padata_parallel_queue *pqueue;
465 struct padata_serial_queue *squeue;
466
467 for_each_cpu(cpu, pd->cpumask.pcpu) {
468 pqueue = per_cpu_ptr(pd->pqueue, cpu);
469 flush_work(&pqueue->work);
470 }
471
472 del_timer_sync(&pd->timer);
473
474 if (atomic_read(&pd->reorder_objects))
475 padata_reorder(pd);
476
477 for_each_cpu(cpu, pd->cpumask.cbcpu) {
478 squeue = per_cpu_ptr(pd->squeue, cpu);
479 flush_work(&squeue->work);
480 }
481
482 BUG_ON(atomic_read(&pd->refcnt) != 0);
483}
484
485static void __padata_start(struct padata_instance *pinst)
486{
487 pinst->flags |= PADATA_INIT;
488}
489
490static void __padata_stop(struct padata_instance *pinst)
491{
492 if (!(pinst->flags & PADATA_INIT))
493 return;
494
495 pinst->flags &= ~PADATA_INIT;
496
497 synchronize_rcu();
498
499 get_online_cpus();
500 padata_flush_queues(pinst->pd);
501 put_online_cpus();
502}
503
504/* Replace the internal control structure with a new one. */
505static void padata_replace(struct padata_instance *pinst,
506 struct parallel_data *pd_new)
507{
508 struct parallel_data *pd_old = pinst->pd;
509 int notification_mask = 0;
510
511 pinst->flags |= PADATA_RESET;
512
513 rcu_assign_pointer(pinst->pd, pd_new);
514
515 synchronize_rcu();
516
517 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
518 notification_mask |= PADATA_CPU_PARALLEL;
519 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
520 notification_mask |= PADATA_CPU_SERIAL;
521
522 padata_flush_queues(pd_old);
523 padata_free_pd(pd_old);
524
525 if (notification_mask)
526 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
527 notification_mask,
528 &pd_new->cpumask);
529
530 pinst->flags &= ~PADATA_RESET;
531}
532
533/**
534 * padata_register_cpumask_notifier - Registers a notifier that will be called
535 * if either pcpu or cbcpu or both cpumasks change.
536 *
537 * @pinst: A poineter to padata instance
538 * @nblock: A pointer to notifier block.
539 */
540int padata_register_cpumask_notifier(struct padata_instance *pinst,
541 struct notifier_block *nblock)
542{
543 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
544 nblock);
545}
546EXPORT_SYMBOL(padata_register_cpumask_notifier);
547
548/**
549 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
550 * registered earlier using padata_register_cpumask_notifier
551 *
552 * @pinst: A pointer to data instance.
553 * @nlock: A pointer to notifier block.
554 */
555int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
556 struct notifier_block *nblock)
557{
558 return blocking_notifier_chain_unregister(
559 &pinst->cpumask_change_notifier,
560 nblock);
561}
562EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
563
564
565/* If cpumask contains no active cpu, we mark the instance as invalid. */
566static bool padata_validate_cpumask(struct padata_instance *pinst,
567 const struct cpumask *cpumask)
568{
569 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
570 pinst->flags |= PADATA_INVALID;
571 return false;
572 }
573
574 pinst->flags &= ~PADATA_INVALID;
575 return true;
576}
577
578static int __padata_set_cpumasks(struct padata_instance *pinst,
579 cpumask_var_t pcpumask,
580 cpumask_var_t cbcpumask)
581{
582 int valid;
583 struct parallel_data *pd;
584
585 valid = padata_validate_cpumask(pinst, pcpumask);
586 if (!valid) {
587 __padata_stop(pinst);
588 goto out_replace;
589 }
590
591 valid = padata_validate_cpumask(pinst, cbcpumask);
592 if (!valid)
593 __padata_stop(pinst);
594
595out_replace:
596 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
597 if (!pd)
598 return -ENOMEM;
599
600 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
601 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
602
603 padata_replace(pinst, pd);
604
605 if (valid)
606 __padata_start(pinst);
607
608 return 0;
609}
610
611/**
612 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
613 * equivalent to @cpumask.
614 *
615 * @pinst: padata instance
616 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
617 * to parallel and serial cpumasks respectively.
618 * @cpumask: the cpumask to use
619 */
620int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
621 cpumask_var_t cpumask)
622{
623 struct cpumask *serial_mask, *parallel_mask;
624 int err = -EINVAL;
625
626 mutex_lock(&pinst->lock);
627 get_online_cpus();
628
629 switch (cpumask_type) {
630 case PADATA_CPU_PARALLEL:
631 serial_mask = pinst->cpumask.cbcpu;
632 parallel_mask = cpumask;
633 break;
634 case PADATA_CPU_SERIAL:
635 parallel_mask = pinst->cpumask.pcpu;
636 serial_mask = cpumask;
637 break;
638 default:
639 goto out;
640 }
641
642 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
643
644out:
645 put_online_cpus();
646 mutex_unlock(&pinst->lock);
647
648 return err;
649}
650EXPORT_SYMBOL(padata_set_cpumask);
651
652/**
653 * padata_start - start the parallel processing
654 *
655 * @pinst: padata instance to start
656 */
657int padata_start(struct padata_instance *pinst)
658{
659 int err = 0;
660
661 mutex_lock(&pinst->lock);
662
663 if (pinst->flags & PADATA_INVALID)
664 err = -EINVAL;
665
666 __padata_start(pinst);
667
668 mutex_unlock(&pinst->lock);
669
670 return err;
671}
672EXPORT_SYMBOL(padata_start);
673
674/**
675 * padata_stop - stop the parallel processing
676 *
677 * @pinst: padata instance to stop
678 */
679void padata_stop(struct padata_instance *pinst)
680{
681 mutex_lock(&pinst->lock);
682 __padata_stop(pinst);
683 mutex_unlock(&pinst->lock);
684}
685EXPORT_SYMBOL(padata_stop);
686
687#ifdef CONFIG_HOTPLUG_CPU
688
689static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
690{
691 struct parallel_data *pd;
692
693 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
694 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
695 pinst->cpumask.cbcpu);
696 if (!pd)
697 return -ENOMEM;
698
699 padata_replace(pinst, pd);
700
701 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
702 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
703 __padata_start(pinst);
704 }
705
706 return 0;
707}
708
709static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
710{
711 struct parallel_data *pd = NULL;
712
713 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
714
715 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
716 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
717 __padata_stop(pinst);
718
719 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
720 pinst->cpumask.cbcpu);
721 if (!pd)
722 return -ENOMEM;
723
724 padata_replace(pinst, pd);
725
726 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
727 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
728 }
729
730 return 0;
731}
732
733 /**
734 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
735 * padata cpumasks.
736 *
737 * @pinst: padata instance
738 * @cpu: cpu to remove
739 * @mask: bitmask specifying from which cpumask @cpu should be removed
740 * The @mask may be any combination of the following flags:
741 * PADATA_CPU_SERIAL - serial cpumask
742 * PADATA_CPU_PARALLEL - parallel cpumask
743 */
744int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
745{
746 int err;
747
748 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
749 return -EINVAL;
750
751 mutex_lock(&pinst->lock);
752
753 get_online_cpus();
754 if (mask & PADATA_CPU_SERIAL)
755 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
756 if (mask & PADATA_CPU_PARALLEL)
757 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
758
759 err = __padata_remove_cpu(pinst, cpu);
760 put_online_cpus();
761
762 mutex_unlock(&pinst->lock);
763
764 return err;
765}
766EXPORT_SYMBOL(padata_remove_cpu);
767
768static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
769{
770 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
771 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
772}
773
774static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
775{
776 struct padata_instance *pinst;
777 int ret;
778
779 pinst = hlist_entry_safe(node, struct padata_instance, node);
780 if (!pinst_has_cpu(pinst, cpu))
781 return 0;
782
783 mutex_lock(&pinst->lock);
784 ret = __padata_add_cpu(pinst, cpu);
785 mutex_unlock(&pinst->lock);
786 return ret;
787}
788
789static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
790{
791 struct padata_instance *pinst;
792 int ret;
793
794 pinst = hlist_entry_safe(node, struct padata_instance, node);
795 if (!pinst_has_cpu(pinst, cpu))
796 return 0;
797
798 mutex_lock(&pinst->lock);
799 ret = __padata_remove_cpu(pinst, cpu);
800 mutex_unlock(&pinst->lock);
801 return ret;
802}
803
804static enum cpuhp_state hp_online;
805#endif
806
807static void __padata_free(struct padata_instance *pinst)
808{
809#ifdef CONFIG_HOTPLUG_CPU
810 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
811#endif
812
813 padata_stop(pinst);
814 padata_free_pd(pinst->pd);
815 free_cpumask_var(pinst->cpumask.pcpu);
816 free_cpumask_var(pinst->cpumask.cbcpu);
817 kfree(pinst);
818}
819
820#define kobj2pinst(_kobj) \
821 container_of(_kobj, struct padata_instance, kobj)
822#define attr2pentry(_attr) \
823 container_of(_attr, struct padata_sysfs_entry, attr)
824
825static void padata_sysfs_release(struct kobject *kobj)
826{
827 struct padata_instance *pinst = kobj2pinst(kobj);
828 __padata_free(pinst);
829}
830
831struct padata_sysfs_entry {
832 struct attribute attr;
833 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
834 ssize_t (*store)(struct padata_instance *, struct attribute *,
835 const char *, size_t);
836};
837
838static ssize_t show_cpumask(struct padata_instance *pinst,
839 struct attribute *attr, char *buf)
840{
841 struct cpumask *cpumask;
842 ssize_t len;
843
844 mutex_lock(&pinst->lock);
845 if (!strcmp(attr->name, "serial_cpumask"))
846 cpumask = pinst->cpumask.cbcpu;
847 else
848 cpumask = pinst->cpumask.pcpu;
849
850 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
851 nr_cpu_ids, cpumask_bits(cpumask));
852 mutex_unlock(&pinst->lock);
853 return len < PAGE_SIZE ? len : -EINVAL;
854}
855
856static ssize_t store_cpumask(struct padata_instance *pinst,
857 struct attribute *attr,
858 const char *buf, size_t count)
859{
860 cpumask_var_t new_cpumask;
861 ssize_t ret;
862 int mask_type;
863
864 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
865 return -ENOMEM;
866
867 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
868 nr_cpumask_bits);
869 if (ret < 0)
870 goto out;
871
872 mask_type = !strcmp(attr->name, "serial_cpumask") ?
873 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
874 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
875 if (!ret)
876 ret = count;
877
878out:
879 free_cpumask_var(new_cpumask);
880 return ret;
881}
882
883#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
884 static struct padata_sysfs_entry _name##_attr = \
885 __ATTR(_name, 0644, _show_name, _store_name)
886#define PADATA_ATTR_RO(_name, _show_name) \
887 static struct padata_sysfs_entry _name##_attr = \
888 __ATTR(_name, 0400, _show_name, NULL)
889
890PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
891PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
892
893/*
894 * Padata sysfs provides the following objects:
895 * serial_cpumask [RW] - cpumask for serial workers
896 * parallel_cpumask [RW] - cpumask for parallel workers
897 */
898static struct attribute *padata_default_attrs[] = {
899 &serial_cpumask_attr.attr,
900 &parallel_cpumask_attr.attr,
901 NULL,
902};
903
904static ssize_t padata_sysfs_show(struct kobject *kobj,
905 struct attribute *attr, char *buf)
906{
907 struct padata_instance *pinst;
908 struct padata_sysfs_entry *pentry;
909 ssize_t ret = -EIO;
910
911 pinst = kobj2pinst(kobj);
912 pentry = attr2pentry(attr);
913 if (pentry->show)
914 ret = pentry->show(pinst, attr, buf);
915
916 return ret;
917}
918
919static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
920 const char *buf, size_t count)
921{
922 struct padata_instance *pinst;
923 struct padata_sysfs_entry *pentry;
924 ssize_t ret = -EIO;
925
926 pinst = kobj2pinst(kobj);
927 pentry = attr2pentry(attr);
928 if (pentry->show)
929 ret = pentry->store(pinst, attr, buf, count);
930
931 return ret;
932}
933
934static const struct sysfs_ops padata_sysfs_ops = {
935 .show = padata_sysfs_show,
936 .store = padata_sysfs_store,
937};
938
939static struct kobj_type padata_attr_type = {
940 .sysfs_ops = &padata_sysfs_ops,
941 .default_attrs = padata_default_attrs,
942 .release = padata_sysfs_release,
943};
944
945/**
946 * padata_alloc_possible - Allocate and initialize padata instance.
947 * Use the cpu_possible_mask for serial and
948 * parallel workers.
949 *
950 * @wq: workqueue to use for the allocated padata instance
951 */
952struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
953{
954 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
955}
956EXPORT_SYMBOL(padata_alloc_possible);
957
958/**
959 * padata_alloc - allocate and initialize a padata instance and specify
960 * cpumasks for serial and parallel workers.
961 *
962 * @wq: workqueue to use for the allocated padata instance
963 * @pcpumask: cpumask that will be used for padata parallelization
964 * @cbcpumask: cpumask that will be used for padata serialization
965 */
966struct padata_instance *padata_alloc(struct workqueue_struct *wq,
967 const struct cpumask *pcpumask,
968 const struct cpumask *cbcpumask)
969{
970 struct padata_instance *pinst;
971 struct parallel_data *pd = NULL;
972
973 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
974 if (!pinst)
975 goto err;
976
977 get_online_cpus();
978 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
979 goto err_free_inst;
980 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
981 free_cpumask_var(pinst->cpumask.pcpu);
982 goto err_free_inst;
983 }
984 if (!padata_validate_cpumask(pinst, pcpumask) ||
985 !padata_validate_cpumask(pinst, cbcpumask))
986 goto err_free_masks;
987
988 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
989 if (!pd)
990 goto err_free_masks;
991
992 rcu_assign_pointer(pinst->pd, pd);
993
994 pinst->wq = wq;
995
996 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
997 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
998
999 pinst->flags = 0;
1000
1001 put_online_cpus();
1002
1003 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1004 kobject_init(&pinst->kobj, &padata_attr_type);
1005 mutex_init(&pinst->lock);
1006
1007#ifdef CONFIG_HOTPLUG_CPU
1008 cpuhp_state_add_instance_nocalls(hp_online, &pinst->node);
1009#endif
1010 return pinst;
1011
1012err_free_masks:
1013 free_cpumask_var(pinst->cpumask.pcpu);
1014 free_cpumask_var(pinst->cpumask.cbcpu);
1015err_free_inst:
1016 kfree(pinst);
1017 put_online_cpus();
1018err:
1019 return NULL;
1020}
1021
1022/**
1023 * padata_free - free a padata instance
1024 *
1025 * @padata_inst: padata instance to free
1026 */
1027void padata_free(struct padata_instance *pinst)
1028{
1029 kobject_put(&pinst->kobj);
1030}
1031EXPORT_SYMBOL(padata_free);
1032
1033#ifdef CONFIG_HOTPLUG_CPU
1034
1035static __init int padata_driver_init(void)
1036{
1037 int ret;
1038
1039 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1040 padata_cpu_online,
1041 padata_cpu_prep_down);
1042 if (ret < 0)
1043 return ret;
1044 hp_online = ret;
1045 return 0;
1046}
1047module_init(padata_driver_init);
1048
1049static __exit void padata_driver_exit(void)
1050{
1051 cpuhp_remove_multi_state(hp_online);
1052}
1053module_exit(padata_driver_exit);
1054#endif
1055
generated by cgit at 2024-05-18 14:35:49 (GMT)