projects/linux·blob v5.6-rc6 · refs

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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * padata.c - generic interface to process data streams in parallel
4 *
5 * See Documentation/core-api/padata.rst for more information.
6 *
7 * Copyright (C) 2008, 2009 secunet Security Networks AG
8 * Copyright (C) 2008, 2009 Steffen Klassert <[email protected]>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms and conditions of the GNU General Public License,
12 * version 2, as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
17 * more details.
18 *
19 * You should have received a copy of the GNU General Public License along with
20 * this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
22 */
23
24#include <linux/export.h>
25#include <linux/cpumask.h>
26#include <linux/err.h>
27#include <linux/cpu.h>
28#include <linux/padata.h>
29#include <linux/mutex.h>
30#include <linux/sched.h>
31#include <linux/slab.h>
32#include <linux/sysfs.h>
33#include <linux/rcupdate.h>
34#include <linux/module.h>
35
36#define MAX_OBJ_NUM 1000
37
38static void padata_free_pd(struct parallel_data *pd);
39
40static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
41{
42 int cpu, target_cpu;
43
44 target_cpu = cpumask_first(pd->cpumask.pcpu);
45 for (cpu = 0; cpu < cpu_index; cpu++)
46 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
47
48 return target_cpu;
49}
50
51static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
52{
53 /*
54 * Hash the sequence numbers to the cpus by taking
55 * seq_nr mod. number of cpus in use.
56 */
57 int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
58
59 return padata_index_to_cpu(pd, cpu_index);
60}
61
62static void padata_parallel_worker(struct work_struct *parallel_work)
63{
64 struct padata_parallel_queue *pqueue;
65 LIST_HEAD(local_list);
66
67 local_bh_disable();
68 pqueue = container_of(parallel_work,
69 struct padata_parallel_queue, work);
70
71 spin_lock(&pqueue->parallel.lock);
72 list_replace_init(&pqueue->parallel.list, &local_list);
73 spin_unlock(&pqueue->parallel.lock);
74
75 while (!list_empty(&local_list)) {
76 struct padata_priv *padata;
77
78 padata = list_entry(local_list.next,
79 struct padata_priv, list);
80
81 list_del_init(&padata->list);
82
83 padata->parallel(padata);
84 }
85
86 local_bh_enable();
87}
88
89/**
90 * padata_do_parallel - padata parallelization function
91 *
92 * @ps: padatashell
93 * @padata: object to be parallelized
94 * @cb_cpu: pointer to the CPU that the serialization callback function should
95 * run on. If it's not in the serial cpumask of @pinst
96 * (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
97 * none found, returns -EINVAL.
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 * Return: 0 on success or else negative error code.
104 */
105int padata_do_parallel(struct padata_shell *ps,
106 struct padata_priv *padata, int *cb_cpu)
107{
108 struct padata_instance *pinst = ps->pinst;
109 int i, cpu, cpu_index, 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(ps->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 if (!cpumask_weight(pd->cpumask.cbcpu))
123 goto out;
124
125 /* Select an alternate fallback CPU and notify the caller. */
126 cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
127
128 cpu = cpumask_first(pd->cpumask.cbcpu);
129 for (i = 0; i < cpu_index; i++)
130 cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
131
132 *cb_cpu = cpu;
133 }
134
135 err = -EBUSY;
136 if ((pinst->flags & PADATA_RESET))
137 goto out;
138
139 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
140 goto out;
141
142 err = 0;
143 atomic_inc(&pd->refcnt);
144 padata->pd = pd;
145 padata->cb_cpu = *cb_cpu;
146
147 padata->seq_nr = atomic_inc_return(&pd->seq_nr);
148 target_cpu = padata_cpu_hash(pd, padata->seq_nr);
149 padata->cpu = target_cpu;
150 queue = per_cpu_ptr(pd->pqueue, target_cpu);
151
152 spin_lock(&queue->parallel.lock);
153 list_add_tail(&padata->list, &queue->parallel.list);
154 spin_unlock(&queue->parallel.lock);
155
156 queue_work(pinst->parallel_wq, &queue->work);
157
158out:
159 rcu_read_unlock_bh();
160
161 return err;
162}
163EXPORT_SYMBOL(padata_do_parallel);
164
165/*
166 * padata_find_next - Find the next object that needs serialization.
167 *
168 * Return:
169 * * A pointer to the control struct of the next object that needs
170 * serialization, if present in one of the percpu reorder queues.
171 * * NULL, if the next object that needs serialization will
172 * be parallel processed by another cpu and is not yet present in
173 * the cpu's reorder queue.
174 */
175static struct padata_priv *padata_find_next(struct parallel_data *pd,
176 bool remove_object)
177{
178 struct padata_parallel_queue *next_queue;
179 struct padata_priv *padata;
180 struct padata_list *reorder;
181 int cpu = pd->cpu;
182
183 next_queue = per_cpu_ptr(pd->pqueue, cpu);
184 reorder = &next_queue->reorder;
185
186 spin_lock(&reorder->lock);
187 if (list_empty(&reorder->list)) {
188 spin_unlock(&reorder->lock);
189 return NULL;
190 }
191
192 padata = list_entry(reorder->list.next, struct padata_priv, list);
193
194 /*
195 * Checks the rare case where two or more parallel jobs have hashed to
196 * the same CPU and one of the later ones finishes first.
197 */
198 if (padata->seq_nr != pd->processed) {
199 spin_unlock(&reorder->lock);
200 return NULL;
201 }
202
203 if (remove_object) {
204 list_del_init(&padata->list);
205 ++pd->processed;
206 pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
207 }
208
209 spin_unlock(&reorder->lock);
210 return padata;
211}
212
213static void padata_reorder(struct parallel_data *pd)
214{
215 struct padata_instance *pinst = pd->ps->pinst;
216 int cb_cpu;
217 struct padata_priv *padata;
218 struct padata_serial_queue *squeue;
219 struct padata_parallel_queue *next_queue;
220
221 /*
222 * We need to ensure that only one cpu can work on dequeueing of
223 * the reorder queue the time. Calculating in which percpu reorder
224 * queue the next object will arrive takes some time. A spinlock
225 * would be highly contended. Also it is not clear in which order
226 * the objects arrive to the reorder queues. So a cpu could wait to
227 * get the lock just to notice that there is nothing to do at the
228 * moment. Therefore we use a trylock and let the holder of the lock
229 * care for all the objects enqueued during the holdtime of the lock.
230 */
231 if (!spin_trylock_bh(&pd->lock))
232 return;
233
234 while (1) {
235 padata = padata_find_next(pd, true);
236
237 /*
238 * If the next object that needs serialization is parallel
239 * processed by another cpu and is still on it's way to the
240 * cpu's reorder queue, nothing to do for now.
241 */
242 if (!padata)
243 break;
244
245 cb_cpu = padata->cb_cpu;
246 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
247
248 spin_lock(&squeue->serial.lock);
249 list_add_tail(&padata->list, &squeue->serial.list);
250 spin_unlock(&squeue->serial.lock);
251
252 queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
253 }
254
255 spin_unlock_bh(&pd->lock);
256
257 /*
258 * The next object that needs serialization might have arrived to
259 * the reorder queues in the meantime.
260 *
261 * Ensure reorder queue is read after pd->lock is dropped so we see
262 * new objects from another task in padata_do_serial. Pairs with
263 * smp_mb__after_atomic in padata_do_serial.
264 */
265 smp_mb();
266
267 next_queue = per_cpu_ptr(pd->pqueue, pd->cpu);
268 if (!list_empty(&next_queue->reorder.list) &&
269 padata_find_next(pd, false))
270 queue_work(pinst->serial_wq, &pd->reorder_work);
271}
272
273static void invoke_padata_reorder(struct work_struct *work)
274{
275 struct parallel_data *pd;
276
277 local_bh_disable();
278 pd = container_of(work, struct parallel_data, reorder_work);
279 padata_reorder(pd);
280 local_bh_enable();
281}
282
283static void padata_serial_worker(struct work_struct *serial_work)
284{
285 struct padata_serial_queue *squeue;
286 struct parallel_data *pd;
287 LIST_HEAD(local_list);
288 int cnt;
289
290 local_bh_disable();
291 squeue = container_of(serial_work, struct padata_serial_queue, work);
292 pd = squeue->pd;
293
294 spin_lock(&squeue->serial.lock);
295 list_replace_init(&squeue->serial.list, &local_list);
296 spin_unlock(&squeue->serial.lock);
297
298 cnt = 0;
299
300 while (!list_empty(&local_list)) {
301 struct padata_priv *padata;
302
303 padata = list_entry(local_list.next,
304 struct padata_priv, list);
305
306 list_del_init(&padata->list);
307
308 padata->serial(padata);
309 cnt++;
310 }
311 local_bh_enable();
312
313 if (atomic_sub_and_test(cnt, &pd->refcnt))
314 padata_free_pd(pd);
315}
316
317/**
318 * padata_do_serial - padata serialization function
319 *
320 * @padata: object to be serialized.
321 *
322 * padata_do_serial must be called for every parallelized object.
323 * The serialization callback function will run with BHs off.
324 */
325void padata_do_serial(struct padata_priv *padata)
326{
327 struct parallel_data *pd = padata->pd;
328 struct padata_parallel_queue *pqueue = per_cpu_ptr(pd->pqueue,
329 padata->cpu);
330 struct padata_priv *cur;
331
332 spin_lock(&pqueue->reorder.lock);
333 /* Sort in ascending order of sequence number. */
334 list_for_each_entry_reverse(cur, &pqueue->reorder.list, list)
335 if (cur->seq_nr < padata->seq_nr)
336 break;
337 list_add(&padata->list, &cur->list);
338 spin_unlock(&pqueue->reorder.lock);
339
340 /*
341 * Ensure the addition to the reorder list is ordered correctly
342 * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
343 * in padata_reorder.
344 */
345 smp_mb__after_atomic();
346
347 padata_reorder(pd);
348}
349EXPORT_SYMBOL(padata_do_serial);
350
351static int padata_setup_cpumasks(struct padata_instance *pinst)
352{
353 struct workqueue_attrs *attrs;
354 int err;
355
356 attrs = alloc_workqueue_attrs();
357 if (!attrs)
358 return -ENOMEM;
359
360 /* Restrict parallel_wq workers to pd->cpumask.pcpu. */
361 cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu);
362 err = apply_workqueue_attrs(pinst->parallel_wq, attrs);
363 free_workqueue_attrs(attrs);
364
365 return err;
366}
367
368static int pd_setup_cpumasks(struct parallel_data *pd,
369 const struct cpumask *pcpumask,
370 const struct cpumask *cbcpumask)
371{
372 int err = -ENOMEM;
373
374 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
375 goto out;
376 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
377 goto free_pcpu_mask;
378
379 cpumask_copy(pd->cpumask.pcpu, pcpumask);
380 cpumask_copy(pd->cpumask.cbcpu, cbcpumask);
381
382 return 0;
383
384free_pcpu_mask:
385 free_cpumask_var(pd->cpumask.pcpu);
386out:
387 return err;
388}
389
390static void __padata_list_init(struct padata_list *pd_list)
391{
392 INIT_LIST_HEAD(&pd_list->list);
393 spin_lock_init(&pd_list->lock);
394}
395
396/* Initialize all percpu queues used by serial workers */
397static void padata_init_squeues(struct parallel_data *pd)
398{
399 int cpu;
400 struct padata_serial_queue *squeue;
401
402 for_each_cpu(cpu, pd->cpumask.cbcpu) {
403 squeue = per_cpu_ptr(pd->squeue, cpu);
404 squeue->pd = pd;
405 __padata_list_init(&squeue->serial);
406 INIT_WORK(&squeue->work, padata_serial_worker);
407 }
408}
409
410/* Initialize all percpu queues used by parallel workers */
411static void padata_init_pqueues(struct parallel_data *pd)
412{
413 int cpu;
414 struct padata_parallel_queue *pqueue;
415
416 for_each_cpu(cpu, pd->cpumask.pcpu) {
417 pqueue = per_cpu_ptr(pd->pqueue, cpu);
418
419 __padata_list_init(&pqueue->reorder);
420 __padata_list_init(&pqueue->parallel);
421 INIT_WORK(&pqueue->work, padata_parallel_worker);
422 atomic_set(&pqueue->num_obj, 0);
423 }
424}
425
426/* Allocate and initialize the internal cpumask dependend resources. */
427static struct parallel_data *padata_alloc_pd(struct padata_shell *ps)
428{
429 struct padata_instance *pinst = ps->pinst;
430 const struct cpumask *cbcpumask;
431 const struct cpumask *pcpumask;
432 struct parallel_data *pd;
433
434 cbcpumask = pinst->rcpumask.cbcpu;
435 pcpumask = pinst->rcpumask.pcpu;
436
437 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
438 if (!pd)
439 goto err;
440
441 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
442 if (!pd->pqueue)
443 goto err_free_pd;
444
445 pd->squeue = alloc_percpu(struct padata_serial_queue);
446 if (!pd->squeue)
447 goto err_free_pqueue;
448
449 pd->ps = ps;
450 if (pd_setup_cpumasks(pd, pcpumask, cbcpumask))
451 goto err_free_squeue;
452
453 padata_init_pqueues(pd);
454 padata_init_squeues(pd);
455 atomic_set(&pd->seq_nr, -1);
456 atomic_set(&pd->refcnt, 1);
457 spin_lock_init(&pd->lock);
458 pd->cpu = cpumask_first(pd->cpumask.pcpu);
459 INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
460
461 return pd;
462
463err_free_squeue:
464 free_percpu(pd->squeue);
465err_free_pqueue:
466 free_percpu(pd->pqueue);
467err_free_pd:
468 kfree(pd);
469err:
470 return NULL;
471}
472
473static void padata_free_pd(struct parallel_data *pd)
474{
475 free_cpumask_var(pd->cpumask.pcpu);
476 free_cpumask_var(pd->cpumask.cbcpu);
477 free_percpu(pd->pqueue);
478 free_percpu(pd->squeue);
479 kfree(pd);
480}
481
482static void __padata_start(struct padata_instance *pinst)
483{
484 pinst->flags |= PADATA_INIT;
485}
486
487static void __padata_stop(struct padata_instance *pinst)
488{
489 if (!(pinst->flags & PADATA_INIT))
490 return;
491
492 pinst->flags &= ~PADATA_INIT;
493
494 synchronize_rcu();
495}
496
497/* Replace the internal control structure with a new one. */
498static int padata_replace_one(struct padata_shell *ps)
499{
500 struct parallel_data *pd_new;
501
502 pd_new = padata_alloc_pd(ps);
503 if (!pd_new)
504 return -ENOMEM;
505
506 ps->opd = rcu_dereference_protected(ps->pd, 1);
507 rcu_assign_pointer(ps->pd, pd_new);
508
509 return 0;
510}
511
512static int padata_replace(struct padata_instance *pinst)
513{
514 struct padata_shell *ps;
515 int err;
516
517 pinst->flags |= PADATA_RESET;
518
519 cpumask_and(pinst->rcpumask.pcpu, pinst->cpumask.pcpu,
520 cpu_online_mask);
521
522 cpumask_and(pinst->rcpumask.cbcpu, pinst->cpumask.cbcpu,
523 cpu_online_mask);
524
525 list_for_each_entry(ps, &pinst->pslist, list) {
526 err = padata_replace_one(ps);
527 if (err)
528 break;
529 }
530
531 synchronize_rcu();
532
533 list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
534 if (atomic_dec_and_test(&ps->opd->refcnt))
535 padata_free_pd(ps->opd);
536
537 pinst->flags &= ~PADATA_RESET;
538
539 return err;
540}
541
542/* If cpumask contains no active cpu, we mark the instance as invalid. */
543static bool padata_validate_cpumask(struct padata_instance *pinst,
544 const struct cpumask *cpumask)
545{
546 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
547 pinst->flags |= PADATA_INVALID;
548 return false;
549 }
550
551 pinst->flags &= ~PADATA_INVALID;
552 return true;
553}
554
555static int __padata_set_cpumasks(struct padata_instance *pinst,
556 cpumask_var_t pcpumask,
557 cpumask_var_t cbcpumask)
558{
559 int valid;
560 int err;
561
562 valid = padata_validate_cpumask(pinst, pcpumask);
563 if (!valid) {
564 __padata_stop(pinst);
565 goto out_replace;
566 }
567
568 valid = padata_validate_cpumask(pinst, cbcpumask);
569 if (!valid)
570 __padata_stop(pinst);
571
572out_replace:
573 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
574 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
575
576 err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst);
577
578 if (valid)
579 __padata_start(pinst);
580
581 return err;
582}
583
584/**
585 * padata_set_cpumask - Sets specified by @cpumask_type cpumask to the value
586 * equivalent to @cpumask.
587 * @pinst: padata instance
588 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
589 * to parallel and serial cpumasks respectively.
590 * @cpumask: the cpumask to use
591 *
592 * Return: 0 on success or negative error code
593 */
594int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
595 cpumask_var_t cpumask)
596{
597 struct cpumask *serial_mask, *parallel_mask;
598 int err = -EINVAL;
599
600 get_online_cpus();
601 mutex_lock(&pinst->lock);
602
603 switch (cpumask_type) {
604 case PADATA_CPU_PARALLEL:
605 serial_mask = pinst->cpumask.cbcpu;
606 parallel_mask = cpumask;
607 break;
608 case PADATA_CPU_SERIAL:
609 parallel_mask = pinst->cpumask.pcpu;
610 serial_mask = cpumask;
611 break;
612 default:
613 goto out;
614 }
615
616 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
617
618out:
619 mutex_unlock(&pinst->lock);
620 put_online_cpus();
621
622 return err;
623}
624EXPORT_SYMBOL(padata_set_cpumask);
625
626/**
627 * padata_start - start the parallel processing
628 *
629 * @pinst: padata instance to start
630 *
631 * Return: 0 on success or negative error code
632 */
633int padata_start(struct padata_instance *pinst)
634{
635 int err = 0;
636
637 mutex_lock(&pinst->lock);
638
639 if (pinst->flags & PADATA_INVALID)
640 err = -EINVAL;
641
642 __padata_start(pinst);
643
644 mutex_unlock(&pinst->lock);
645
646 return err;
647}
648EXPORT_SYMBOL(padata_start);
649
650/**
651 * padata_stop - stop the parallel processing
652 *
653 * @pinst: padata instance to stop
654 */
655void padata_stop(struct padata_instance *pinst)
656{
657 mutex_lock(&pinst->lock);
658 __padata_stop(pinst);
659 mutex_unlock(&pinst->lock);
660}
661EXPORT_SYMBOL(padata_stop);
662
663#ifdef CONFIG_HOTPLUG_CPU
664
665static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
666{
667 int err = 0;
668
669 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
670 err = padata_replace(pinst);
671
672 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
673 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
674 __padata_start(pinst);
675 }
676
677 return err;
678}
679
680static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
681{
682 int err = 0;
683
684 if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
685 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
686 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
687 __padata_stop(pinst);
688
689 err = padata_replace(pinst);
690 }
691
692 return err;
693}
694
695static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
696{
697 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
698 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
699}
700
701static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
702{
703 struct padata_instance *pinst;
704 int ret;
705
706 pinst = hlist_entry_safe(node, struct padata_instance, node);
707 if (!pinst_has_cpu(pinst, cpu))
708 return 0;
709
710 mutex_lock(&pinst->lock);
711 ret = __padata_add_cpu(pinst, cpu);
712 mutex_unlock(&pinst->lock);
713 return ret;
714}
715
716static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node)
717{
718 struct padata_instance *pinst;
719 int ret;
720
721 pinst = hlist_entry_safe(node, struct padata_instance, node);
722 if (!pinst_has_cpu(pinst, cpu))
723 return 0;
724
725 mutex_lock(&pinst->lock);
726 ret = __padata_remove_cpu(pinst, cpu);
727 mutex_unlock(&pinst->lock);
728 return ret;
729}
730
731static enum cpuhp_state hp_online;
732#endif
733
734static void __padata_free(struct padata_instance *pinst)
735{
736#ifdef CONFIG_HOTPLUG_CPU
737 cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD, &pinst->node);
738 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
739#endif
740
741 WARN_ON(!list_empty(&pinst->pslist));
742
743 padata_stop(pinst);
744 free_cpumask_var(pinst->rcpumask.cbcpu);
745 free_cpumask_var(pinst->rcpumask.pcpu);
746 free_cpumask_var(pinst->cpumask.pcpu);
747 free_cpumask_var(pinst->cpumask.cbcpu);
748 destroy_workqueue(pinst->serial_wq);
749 destroy_workqueue(pinst->parallel_wq);
750 kfree(pinst);
751}
752
753#define kobj2pinst(_kobj) \
754 container_of(_kobj, struct padata_instance, kobj)
755#define attr2pentry(_attr) \
756 container_of(_attr, struct padata_sysfs_entry, attr)
757
758static void padata_sysfs_release(struct kobject *kobj)
759{
760 struct padata_instance *pinst = kobj2pinst(kobj);
761 __padata_free(pinst);
762}
763
764struct padata_sysfs_entry {
765 struct attribute attr;
766 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
767 ssize_t (*store)(struct padata_instance *, struct attribute *,
768 const char *, size_t);
769};
770
771static ssize_t show_cpumask(struct padata_instance *pinst,
772 struct attribute *attr, char *buf)
773{
774 struct cpumask *cpumask;
775 ssize_t len;
776
777 mutex_lock(&pinst->lock);
778 if (!strcmp(attr->name, "serial_cpumask"))
779 cpumask = pinst->cpumask.cbcpu;
780 else
781 cpumask = pinst->cpumask.pcpu;
782
783 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
784 nr_cpu_ids, cpumask_bits(cpumask));
785 mutex_unlock(&pinst->lock);
786 return len < PAGE_SIZE ? len : -EINVAL;
787}
788
789static ssize_t store_cpumask(struct padata_instance *pinst,
790 struct attribute *attr,
791 const char *buf, size_t count)
792{
793 cpumask_var_t new_cpumask;
794 ssize_t ret;
795 int mask_type;
796
797 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
798 return -ENOMEM;
799
800 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
801 nr_cpumask_bits);
802 if (ret < 0)
803 goto out;
804
805 mask_type = !strcmp(attr->name, "serial_cpumask") ?
806 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
807 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
808 if (!ret)
809 ret = count;
810
811out:
812 free_cpumask_var(new_cpumask);
813 return ret;
814}
815
816#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
817 static struct padata_sysfs_entry _name##_attr = \
818 __ATTR(_name, 0644, _show_name, _store_name)
819#define PADATA_ATTR_RO(_name, _show_name) \
820 static struct padata_sysfs_entry _name##_attr = \
821 __ATTR(_name, 0400, _show_name, NULL)
822
823PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
824PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
825
826/*
827 * Padata sysfs provides the following objects:
828 * serial_cpumask [RW] - cpumask for serial workers
829 * parallel_cpumask [RW] - cpumask for parallel workers
830 */
831static struct attribute *padata_default_attrs[] = {
832 &serial_cpumask_attr.attr,
833 &parallel_cpumask_attr.attr,
834 NULL,
835};
836ATTRIBUTE_GROUPS(padata_default);
837
838static ssize_t padata_sysfs_show(struct kobject *kobj,
839 struct attribute *attr, char *buf)
840{
841 struct padata_instance *pinst;
842 struct padata_sysfs_entry *pentry;
843 ssize_t ret = -EIO;
844
845 pinst = kobj2pinst(kobj);
846 pentry = attr2pentry(attr);
847 if (pentry->show)
848 ret = pentry->show(pinst, attr, buf);
849
850 return ret;
851}
852
853static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
854 const char *buf, size_t count)
855{
856 struct padata_instance *pinst;
857 struct padata_sysfs_entry *pentry;
858 ssize_t ret = -EIO;
859
860 pinst = kobj2pinst(kobj);
861 pentry = attr2pentry(attr);
862 if (pentry->show)
863 ret = pentry->store(pinst, attr, buf, count);
864
865 return ret;
866}
867
868static const struct sysfs_ops padata_sysfs_ops = {
869 .show = padata_sysfs_show,
870 .store = padata_sysfs_store,
871};
872
873static struct kobj_type padata_attr_type = {
874 .sysfs_ops = &padata_sysfs_ops,
875 .default_groups = padata_default_groups,
876 .release = padata_sysfs_release,
877};
878
879/**
880 * padata_alloc - allocate and initialize a padata instance and specify
881 * cpumasks for serial and parallel workers.
882 *
883 * @name: used to identify the instance
884 * @pcpumask: cpumask that will be used for padata parallelization
885 * @cbcpumask: cpumask that will be used for padata serialization
886 *
887 * Return: new instance on success, NULL on error
888 */
889static struct padata_instance *padata_alloc(const char *name,
890 const struct cpumask *pcpumask,
891 const struct cpumask *cbcpumask)
892{
893 struct padata_instance *pinst;
894
895 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
896 if (!pinst)
897 goto err;
898
899 pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
900 name);
901 if (!pinst->parallel_wq)
902 goto err_free_inst;
903
904 get_online_cpus();
905
906 pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
907 WQ_CPU_INTENSIVE, 1, name);
908 if (!pinst->serial_wq)
909 goto err_put_cpus;
910
911 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
912 goto err_free_serial_wq;
913 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
914 free_cpumask_var(pinst->cpumask.pcpu);
915 goto err_free_serial_wq;
916 }
917 if (!padata_validate_cpumask(pinst, pcpumask) ||
918 !padata_validate_cpumask(pinst, cbcpumask))
919 goto err_free_masks;
920
921 if (!alloc_cpumask_var(&pinst->rcpumask.pcpu, GFP_KERNEL))
922 goto err_free_masks;
923 if (!alloc_cpumask_var(&pinst->rcpumask.cbcpu, GFP_KERNEL))
924 goto err_free_rcpumask_pcpu;
925
926 INIT_LIST_HEAD(&pinst->pslist);
927
928 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
929 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
930 cpumask_and(pinst->rcpumask.pcpu, pcpumask, cpu_online_mask);
931 cpumask_and(pinst->rcpumask.cbcpu, cbcpumask, cpu_online_mask);
932
933 if (padata_setup_cpumasks(pinst))
934 goto err_free_rcpumask_cbcpu;
935
936 pinst->flags = 0;
937
938 kobject_init(&pinst->kobj, &padata_attr_type);
939 mutex_init(&pinst->lock);
940
941#ifdef CONFIG_HOTPLUG_CPU
942 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
943 cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
944 &pinst->node);
945#endif
946
947 put_online_cpus();
948
949 return pinst;
950
951err_free_rcpumask_cbcpu:
952 free_cpumask_var(pinst->rcpumask.cbcpu);
953err_free_rcpumask_pcpu:
954 free_cpumask_var(pinst->rcpumask.pcpu);
955err_free_masks:
956 free_cpumask_var(pinst->cpumask.pcpu);
957 free_cpumask_var(pinst->cpumask.cbcpu);
958err_free_serial_wq:
959 destroy_workqueue(pinst->serial_wq);
960err_put_cpus:
961 put_online_cpus();
962 destroy_workqueue(pinst->parallel_wq);
963err_free_inst:
964 kfree(pinst);
965err:
966 return NULL;
967}
968
969/**
970 * padata_alloc_possible - Allocate and initialize padata instance.
971 * Use the cpu_possible_mask for serial and
972 * parallel workers.
973 *
974 * @name: used to identify the instance
975 *
976 * Return: new instance on success, NULL on error
977 */
978struct padata_instance *padata_alloc_possible(const char *name)
979{
980 return padata_alloc(name, cpu_possible_mask, cpu_possible_mask);
981}
982EXPORT_SYMBOL(padata_alloc_possible);
983
984/**
985 * padata_free - free a padata instance
986 *
987 * @pinst: padata instance to free
988 */
989void padata_free(struct padata_instance *pinst)
990{
991 kobject_put(&pinst->kobj);
992}
993EXPORT_SYMBOL(padata_free);
994
995/**
996 * padata_alloc_shell - Allocate and initialize padata shell.
997 *
998 * @pinst: Parent padata_instance object.
999 *
1000 * Return: new shell on success, NULL on error
1001 */
1002struct padata_shell *padata_alloc_shell(struct padata_instance *pinst)
1003{
1004 struct parallel_data *pd;
1005 struct padata_shell *ps;
1006
1007 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1008 if (!ps)
1009 goto out;
1010
1011 ps->pinst = pinst;
1012
1013 get_online_cpus();
1014 pd = padata_alloc_pd(ps);
1015 put_online_cpus();
1016
1017 if (!pd)
1018 goto out_free_ps;
1019
1020 mutex_lock(&pinst->lock);
1021 RCU_INIT_POINTER(ps->pd, pd);
1022 list_add(&ps->list, &pinst->pslist);
1023 mutex_unlock(&pinst->lock);
1024
1025 return ps;
1026
1027out_free_ps:
1028 kfree(ps);
1029out:
1030 return NULL;
1031}
1032EXPORT_SYMBOL(padata_alloc_shell);
1033
1034/**
1035 * padata_free_shell - free a padata shell
1036 *
1037 * @ps: padata shell to free
1038 */
1039void padata_free_shell(struct padata_shell *ps)
1040{
1041 struct padata_instance *pinst = ps->pinst;
1042
1043 mutex_lock(&pinst->lock);
1044 list_del(&ps->list);
1045 padata_free_pd(rcu_dereference_protected(ps->pd, 1));
1046 mutex_unlock(&pinst->lock);
1047
1048 kfree(ps);
1049}
1050EXPORT_SYMBOL(padata_free_shell);
1051
1052#ifdef CONFIG_HOTPLUG_CPU
1053
1054static __init int padata_driver_init(void)
1055{
1056 int ret;
1057
1058 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1059 padata_cpu_online, NULL);
1060 if (ret < 0)
1061 return ret;
1062 hp_online = ret;
1063
1064 ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead",
1065 NULL, padata_cpu_dead);
1066 if (ret < 0) {
1067 cpuhp_remove_multi_state(hp_online);
1068 return ret;
1069 }
1070 return 0;
1071}
1072module_init(padata_driver_init);
1073
1074static __exit void padata_driver_exit(void)
1075{
1076 cpuhp_remove_multi_state(CPUHP_PADATA_DEAD);
1077 cpuhp_remove_multi_state(hp_online);
1078}
1079module_exit(padata_driver_exit);
1080#endif