Loading...
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 <steffen.klassert@secunet.com>
9 *
10 * Copyright (c) 2020 Oracle and/or its affiliates.
11 * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
12 */
13
14#include <linux/completion.h>
15#include <linux/export.h>
16#include <linux/cpumask.h>
17#include <linux/err.h>
18#include <linux/cpu.h>
19#include <linux/padata.h>
20#include <linux/mutex.h>
21#include <linux/sched.h>
22#include <linux/slab.h>
23#include <linux/sysfs.h>
24#include <linux/rcupdate.h>
25
26#define PADATA_WORK_ONSTACK 1 /* Work's memory is on stack */
27
28struct padata_work {
29 struct work_struct pw_work;
30 struct list_head pw_list; /* padata_free_works linkage */
31 void *pw_data;
32};
33
34static DEFINE_SPINLOCK(padata_works_lock);
35static struct padata_work *padata_works;
36static LIST_HEAD(padata_free_works);
37
38struct padata_mt_job_state {
39 spinlock_t lock;
40 struct completion completion;
41 struct padata_mt_job *job;
42 int nworks;
43 int nworks_fini;
44 unsigned long chunk_size;
45};
46
47static void padata_free_pd(struct parallel_data *pd);
48static void __init padata_mt_helper(struct work_struct *work);
49
50static inline void padata_get_pd(struct parallel_data *pd)
51{
52 refcount_inc(&pd->refcnt);
53}
54
55static inline void padata_put_pd_cnt(struct parallel_data *pd, int cnt)
56{
57 if (refcount_sub_and_test(cnt, &pd->refcnt))
58 padata_free_pd(pd);
59}
60
61static inline void padata_put_pd(struct parallel_data *pd)
62{
63 padata_put_pd_cnt(pd, 1);
64}
65
66static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
67{
68 int cpu, target_cpu;
69
70 target_cpu = cpumask_first(pd->cpumask.pcpu);
71 for (cpu = 0; cpu < cpu_index; cpu++)
72 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
73
74 return target_cpu;
75}
76
77static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
78{
79 /*
80 * Hash the sequence numbers to the cpus by taking
81 * seq_nr mod. number of cpus in use.
82 */
83 int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
84
85 return padata_index_to_cpu(pd, cpu_index);
86}
87
88static struct padata_work *padata_work_alloc(void)
89{
90 struct padata_work *pw;
91
92 lockdep_assert_held(&padata_works_lock);
93
94 if (list_empty(&padata_free_works))
95 return NULL; /* No more work items allowed to be queued. */
96
97 pw = list_first_entry(&padata_free_works, struct padata_work, pw_list);
98 list_del(&pw->pw_list);
99 return pw;
100}
101
102/*
103 * This function is marked __ref because this function may be optimized in such
104 * a way that it directly refers to work_fn's address, which causes modpost to
105 * complain when work_fn is marked __init. This scenario was observed with clang
106 * LTO, where padata_work_init() was optimized to refer directly to
107 * padata_mt_helper() because the calls to padata_work_init() with other work_fn
108 * values were eliminated or inlined.
109 */
110static void __ref padata_work_init(struct padata_work *pw, work_func_t work_fn,
111 void *data, int flags)
112{
113 if (flags & PADATA_WORK_ONSTACK)
114 INIT_WORK_ONSTACK(&pw->pw_work, work_fn);
115 else
116 INIT_WORK(&pw->pw_work, work_fn);
117 pw->pw_data = data;
118}
119
120static int __init padata_work_alloc_mt(int nworks, void *data,
121 struct list_head *head)
122{
123 int i;
124
125 spin_lock_bh(&padata_works_lock);
126 /* Start at 1 because the current task participates in the job. */
127 for (i = 1; i < nworks; ++i) {
128 struct padata_work *pw = padata_work_alloc();
129
130 if (!pw)
131 break;
132 padata_work_init(pw, padata_mt_helper, data, 0);
133 list_add(&pw->pw_list, head);
134 }
135 spin_unlock_bh(&padata_works_lock);
136
137 return i;
138}
139
140static void padata_work_free(struct padata_work *pw)
141{
142 lockdep_assert_held(&padata_works_lock);
143 list_add(&pw->pw_list, &padata_free_works);
144}
145
146static void __init padata_works_free(struct list_head *works)
147{
148 struct padata_work *cur, *next;
149
150 if (list_empty(works))
151 return;
152
153 spin_lock_bh(&padata_works_lock);
154 list_for_each_entry_safe(cur, next, works, pw_list) {
155 list_del(&cur->pw_list);
156 padata_work_free(cur);
157 }
158 spin_unlock_bh(&padata_works_lock);
159}
160
161static void padata_parallel_worker(struct work_struct *parallel_work)
162{
163 struct padata_work *pw = container_of(parallel_work, struct padata_work,
164 pw_work);
165 struct padata_priv *padata = pw->pw_data;
166
167 local_bh_disable();
168 padata->parallel(padata);
169 spin_lock(&padata_works_lock);
170 padata_work_free(pw);
171 spin_unlock(&padata_works_lock);
172 local_bh_enable();
173}
174
175/**
176 * padata_do_parallel - padata parallelization function
177 *
178 * @ps: padatashell
179 * @padata: object to be parallelized
180 * @cb_cpu: pointer to the CPU that the serialization callback function should
181 * run on. If it's not in the serial cpumask of @pinst
182 * (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
183 * none found, returns -EINVAL.
184 *
185 * The parallelization callback function will run with BHs off.
186 * Note: Every object which is parallelized by padata_do_parallel
187 * must be seen by padata_do_serial.
188 *
189 * Return: 0 on success or else negative error code.
190 */
191int padata_do_parallel(struct padata_shell *ps,
192 struct padata_priv *padata, int *cb_cpu)
193{
194 struct padata_instance *pinst = ps->pinst;
195 int i, cpu, cpu_index, err;
196 struct parallel_data *pd;
197 struct padata_work *pw;
198
199 rcu_read_lock_bh();
200
201 pd = rcu_dereference_bh(ps->pd);
202
203 err = -EINVAL;
204 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
205 goto out;
206
207 if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
208 if (cpumask_empty(pd->cpumask.cbcpu))
209 goto out;
210
211 /* Select an alternate fallback CPU and notify the caller. */
212 cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
213
214 cpu = cpumask_first(pd->cpumask.cbcpu);
215 for (i = 0; i < cpu_index; i++)
216 cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
217
218 *cb_cpu = cpu;
219 }
220
221 err = -EBUSY;
222 if ((pinst->flags & PADATA_RESET))
223 goto out;
224
225 padata_get_pd(pd);
226 padata->pd = pd;
227 padata->cb_cpu = *cb_cpu;
228
229 spin_lock(&padata_works_lock);
230 padata->seq_nr = ++pd->seq_nr;
231 pw = padata_work_alloc();
232 spin_unlock(&padata_works_lock);
233
234 if (!pw) {
235 /* Maximum works limit exceeded, run in the current task. */
236 padata->parallel(padata);
237 }
238
239 rcu_read_unlock_bh();
240
241 if (pw) {
242 padata_work_init(pw, padata_parallel_worker, padata, 0);
243 queue_work(pinst->parallel_wq, &pw->pw_work);
244 }
245
246 return 0;
247out:
248 rcu_read_unlock_bh();
249
250 return err;
251}
252EXPORT_SYMBOL(padata_do_parallel);
253
254/*
255 * padata_find_next - Find the next object that needs serialization.
256 *
257 * Return:
258 * * A pointer to the control struct of the next object that needs
259 * serialization, if present in one of the percpu reorder queues.
260 * * NULL, if the next object that needs serialization will
261 * be parallel processed by another cpu and is not yet present in
262 * the cpu's reorder queue.
263 */
264static struct padata_priv *padata_find_next(struct parallel_data *pd,
265 bool remove_object)
266{
267 struct padata_priv *padata;
268 struct padata_list *reorder;
269 int cpu = pd->cpu;
270
271 reorder = per_cpu_ptr(pd->reorder_list, cpu);
272
273 spin_lock(&reorder->lock);
274 if (list_empty(&reorder->list)) {
275 spin_unlock(&reorder->lock);
276 return NULL;
277 }
278
279 padata = list_entry(reorder->list.next, struct padata_priv, list);
280
281 /*
282 * Checks the rare case where two or more parallel jobs have hashed to
283 * the same CPU and one of the later ones finishes first.
284 */
285 if (padata->seq_nr != pd->processed) {
286 spin_unlock(&reorder->lock);
287 return NULL;
288 }
289
290 if (remove_object) {
291 list_del_init(&padata->list);
292 ++pd->processed;
293 pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
294 }
295
296 spin_unlock(&reorder->lock);
297 return padata;
298}
299
300static void padata_reorder(struct parallel_data *pd)
301{
302 struct padata_instance *pinst = pd->ps->pinst;
303 int cb_cpu;
304 struct padata_priv *padata;
305 struct padata_serial_queue *squeue;
306 struct padata_list *reorder;
307
308 /*
309 * We need to ensure that only one cpu can work on dequeueing of
310 * the reorder queue the time. Calculating in which percpu reorder
311 * queue the next object will arrive takes some time. A spinlock
312 * would be highly contended. Also it is not clear in which order
313 * the objects arrive to the reorder queues. So a cpu could wait to
314 * get the lock just to notice that there is nothing to do at the
315 * moment. Therefore we use a trylock and let the holder of the lock
316 * care for all the objects enqueued during the holdtime of the lock.
317 */
318 if (!spin_trylock_bh(&pd->lock))
319 return;
320
321 while (1) {
322 padata = padata_find_next(pd, true);
323
324 /*
325 * If the next object that needs serialization is parallel
326 * processed by another cpu and is still on it's way to the
327 * cpu's reorder queue, nothing to do for now.
328 */
329 if (!padata)
330 break;
331
332 cb_cpu = padata->cb_cpu;
333 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
334
335 spin_lock(&squeue->serial.lock);
336 list_add_tail(&padata->list, &squeue->serial.list);
337 spin_unlock(&squeue->serial.lock);
338
339 queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
340 }
341
342 spin_unlock_bh(&pd->lock);
343
344 /*
345 * The next object that needs serialization might have arrived to
346 * the reorder queues in the meantime.
347 *
348 * Ensure reorder queue is read after pd->lock is dropped so we see
349 * new objects from another task in padata_do_serial. Pairs with
350 * smp_mb in padata_do_serial.
351 */
352 smp_mb();
353
354 reorder = per_cpu_ptr(pd->reorder_list, pd->cpu);
355 if (!list_empty(&reorder->list) && padata_find_next(pd, false)) {
356 /*
357 * Other context(eg. the padata_serial_worker) can finish the request.
358 * To avoid UAF issue, add pd ref here, and put pd ref after reorder_work finish.
359 */
360 padata_get_pd(pd);
361 queue_work(pinst->serial_wq, &pd->reorder_work);
362 }
363}
364
365static void invoke_padata_reorder(struct work_struct *work)
366{
367 struct parallel_data *pd;
368
369 local_bh_disable();
370 pd = container_of(work, struct parallel_data, reorder_work);
371 padata_reorder(pd);
372 local_bh_enable();
373 /* Pairs with putting the reorder_work in the serial_wq */
374 padata_put_pd(pd);
375}
376
377static void padata_serial_worker(struct work_struct *serial_work)
378{
379 struct padata_serial_queue *squeue;
380 struct parallel_data *pd;
381 LIST_HEAD(local_list);
382 int cnt;
383
384 local_bh_disable();
385 squeue = container_of(serial_work, struct padata_serial_queue, work);
386 pd = squeue->pd;
387
388 spin_lock(&squeue->serial.lock);
389 list_replace_init(&squeue->serial.list, &local_list);
390 spin_unlock(&squeue->serial.lock);
391
392 cnt = 0;
393
394 while (!list_empty(&local_list)) {
395 struct padata_priv *padata;
396
397 padata = list_entry(local_list.next,
398 struct padata_priv, list);
399
400 list_del_init(&padata->list);
401
402 padata->serial(padata);
403 cnt++;
404 }
405 local_bh_enable();
406
407 padata_put_pd_cnt(pd, cnt);
408}
409
410/**
411 * padata_do_serial - padata serialization function
412 *
413 * @padata: object to be serialized.
414 *
415 * padata_do_serial must be called for every parallelized object.
416 * The serialization callback function will run with BHs off.
417 */
418void padata_do_serial(struct padata_priv *padata)
419{
420 struct parallel_data *pd = padata->pd;
421 int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr);
422 struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu);
423 struct padata_priv *cur;
424 struct list_head *pos;
425
426 spin_lock(&reorder->lock);
427 /* Sort in ascending order of sequence number. */
428 list_for_each_prev(pos, &reorder->list) {
429 cur = list_entry(pos, struct padata_priv, list);
430 /* Compare by difference to consider integer wrap around */
431 if ((signed int)(cur->seq_nr - padata->seq_nr) < 0)
432 break;
433 }
434 list_add(&padata->list, pos);
435 spin_unlock(&reorder->lock);
436
437 /*
438 * Ensure the addition to the reorder list is ordered correctly
439 * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
440 * in padata_reorder.
441 */
442 smp_mb();
443
444 padata_reorder(pd);
445}
446EXPORT_SYMBOL(padata_do_serial);
447
448static int padata_setup_cpumasks(struct padata_instance *pinst)
449{
450 struct workqueue_attrs *attrs;
451 int err;
452
453 attrs = alloc_workqueue_attrs();
454 if (!attrs)
455 return -ENOMEM;
456
457 /* Restrict parallel_wq workers to pd->cpumask.pcpu. */
458 cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu);
459 err = apply_workqueue_attrs(pinst->parallel_wq, attrs);
460 free_workqueue_attrs(attrs);
461
462 return err;
463}
464
465static void __init padata_mt_helper(struct work_struct *w)
466{
467 struct padata_work *pw = container_of(w, struct padata_work, pw_work);
468 struct padata_mt_job_state *ps = pw->pw_data;
469 struct padata_mt_job *job = ps->job;
470 bool done;
471
472 spin_lock(&ps->lock);
473
474 while (job->size > 0) {
475 unsigned long start, size, end;
476
477 start = job->start;
478 /* So end is chunk size aligned if enough work remains. */
479 size = roundup(start + 1, ps->chunk_size) - start;
480 size = min(size, job->size);
481 end = start + size;
482
483 job->start = end;
484 job->size -= size;
485
486 spin_unlock(&ps->lock);
487 job->thread_fn(start, end, job->fn_arg);
488 spin_lock(&ps->lock);
489 }
490
491 ++ps->nworks_fini;
492 done = (ps->nworks_fini == ps->nworks);
493 spin_unlock(&ps->lock);
494
495 if (done)
496 complete(&ps->completion);
497}
498
499/**
500 * padata_do_multithreaded - run a multithreaded job
501 * @job: Description of the job.
502 *
503 * See the definition of struct padata_mt_job for more details.
504 */
505void __init padata_do_multithreaded(struct padata_mt_job *job)
506{
507 /* In case threads finish at different times. */
508 static const unsigned long load_balance_factor = 4;
509 struct padata_work my_work, *pw;
510 struct padata_mt_job_state ps;
511 LIST_HEAD(works);
512 int nworks, nid;
513 static atomic_t last_used_nid __initdata;
514
515 if (job->size == 0)
516 return;
517
518 /* Ensure at least one thread when size < min_chunk. */
519 nworks = max(job->size / max(job->min_chunk, job->align), 1ul);
520 nworks = min(nworks, job->max_threads);
521
522 if (nworks == 1) {
523 /* Single thread, no coordination needed, cut to the chase. */
524 job->thread_fn(job->start, job->start + job->size, job->fn_arg);
525 return;
526 }
527
528 spin_lock_init(&ps.lock);
529 init_completion(&ps.completion);
530 ps.job = job;
531 ps.nworks = padata_work_alloc_mt(nworks, &ps, &works);
532 ps.nworks_fini = 0;
533
534 /*
535 * Chunk size is the amount of work a helper does per call to the
536 * thread function. Load balance large jobs between threads by
537 * increasing the number of chunks, guarantee at least the minimum
538 * chunk size from the caller, and honor the caller's alignment.
539 * Ensure chunk_size is at least 1 to prevent divide-by-0
540 * panic in padata_mt_helper().
541 */
542 ps.chunk_size = job->size / (ps.nworks * load_balance_factor);
543 ps.chunk_size = max(ps.chunk_size, job->min_chunk);
544 ps.chunk_size = max(ps.chunk_size, 1ul);
545 ps.chunk_size = roundup(ps.chunk_size, job->align);
546
547 list_for_each_entry(pw, &works, pw_list)
548 if (job->numa_aware) {
549 int old_node = atomic_read(&last_used_nid);
550
551 do {
552 nid = next_node_in(old_node, node_states[N_CPU]);
553 } while (!atomic_try_cmpxchg(&last_used_nid, &old_node, nid));
554 queue_work_node(nid, system_unbound_wq, &pw->pw_work);
555 } else {
556 queue_work(system_unbound_wq, &pw->pw_work);
557 }
558
559 /* Use the current thread, which saves starting a workqueue worker. */
560 padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK);
561 padata_mt_helper(&my_work.pw_work);
562
563 /* Wait for all the helpers to finish. */
564 wait_for_completion(&ps.completion);
565
566 destroy_work_on_stack(&my_work.pw_work);
567 padata_works_free(&works);
568}
569
570static void __padata_list_init(struct padata_list *pd_list)
571{
572 INIT_LIST_HEAD(&pd_list->list);
573 spin_lock_init(&pd_list->lock);
574}
575
576/* Initialize all percpu queues used by serial workers */
577static void padata_init_squeues(struct parallel_data *pd)
578{
579 int cpu;
580 struct padata_serial_queue *squeue;
581
582 for_each_cpu(cpu, pd->cpumask.cbcpu) {
583 squeue = per_cpu_ptr(pd->squeue, cpu);
584 squeue->pd = pd;
585 __padata_list_init(&squeue->serial);
586 INIT_WORK(&squeue->work, padata_serial_worker);
587 }
588}
589
590/* Initialize per-CPU reorder lists */
591static void padata_init_reorder_list(struct parallel_data *pd)
592{
593 int cpu;
594 struct padata_list *list;
595
596 for_each_cpu(cpu, pd->cpumask.pcpu) {
597 list = per_cpu_ptr(pd->reorder_list, cpu);
598 __padata_list_init(list);
599 }
600}
601
602/* Allocate and initialize the internal cpumask dependend resources. */
603static struct parallel_data *padata_alloc_pd(struct padata_shell *ps)
604{
605 struct padata_instance *pinst = ps->pinst;
606 struct parallel_data *pd;
607
608 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
609 if (!pd)
610 goto err;
611
612 pd->reorder_list = alloc_percpu(struct padata_list);
613 if (!pd->reorder_list)
614 goto err_free_pd;
615
616 pd->squeue = alloc_percpu(struct padata_serial_queue);
617 if (!pd->squeue)
618 goto err_free_reorder_list;
619
620 pd->ps = ps;
621
622 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
623 goto err_free_squeue;
624 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
625 goto err_free_pcpu;
626
627 cpumask_and(pd->cpumask.pcpu, pinst->cpumask.pcpu, cpu_online_mask);
628 cpumask_and(pd->cpumask.cbcpu, pinst->cpumask.cbcpu, cpu_online_mask);
629
630 padata_init_reorder_list(pd);
631 padata_init_squeues(pd);
632 pd->seq_nr = -1;
633 refcount_set(&pd->refcnt, 1);
634 spin_lock_init(&pd->lock);
635 pd->cpu = cpumask_first(pd->cpumask.pcpu);
636 INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
637
638 return pd;
639
640err_free_pcpu:
641 free_cpumask_var(pd->cpumask.pcpu);
642err_free_squeue:
643 free_percpu(pd->squeue);
644err_free_reorder_list:
645 free_percpu(pd->reorder_list);
646err_free_pd:
647 kfree(pd);
648err:
649 return NULL;
650}
651
652static void padata_free_pd(struct parallel_data *pd)
653{
654 free_cpumask_var(pd->cpumask.pcpu);
655 free_cpumask_var(pd->cpumask.cbcpu);
656 free_percpu(pd->reorder_list);
657 free_percpu(pd->squeue);
658 kfree(pd);
659}
660
661static void __padata_start(struct padata_instance *pinst)
662{
663 pinst->flags |= PADATA_INIT;
664}
665
666static void __padata_stop(struct padata_instance *pinst)
667{
668 if (!(pinst->flags & PADATA_INIT))
669 return;
670
671 pinst->flags &= ~PADATA_INIT;
672
673 synchronize_rcu();
674}
675
676/* Replace the internal control structure with a new one. */
677static int padata_replace_one(struct padata_shell *ps)
678{
679 struct parallel_data *pd_new;
680
681 pd_new = padata_alloc_pd(ps);
682 if (!pd_new)
683 return -ENOMEM;
684
685 ps->opd = rcu_dereference_protected(ps->pd, 1);
686 rcu_assign_pointer(ps->pd, pd_new);
687
688 return 0;
689}
690
691static int padata_replace(struct padata_instance *pinst)
692{
693 struct padata_shell *ps;
694 int err = 0;
695
696 pinst->flags |= PADATA_RESET;
697
698 list_for_each_entry(ps, &pinst->pslist, list) {
699 err = padata_replace_one(ps);
700 if (err)
701 break;
702 }
703
704 synchronize_rcu();
705
706 list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
707 padata_put_pd(ps->opd);
708
709 pinst->flags &= ~PADATA_RESET;
710
711 return err;
712}
713
714/* If cpumask contains no active cpu, we mark the instance as invalid. */
715static bool padata_validate_cpumask(struct padata_instance *pinst,
716 const struct cpumask *cpumask)
717{
718 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
719 pinst->flags |= PADATA_INVALID;
720 return false;
721 }
722
723 pinst->flags &= ~PADATA_INVALID;
724 return true;
725}
726
727static int __padata_set_cpumasks(struct padata_instance *pinst,
728 cpumask_var_t pcpumask,
729 cpumask_var_t cbcpumask)
730{
731 int valid;
732 int err;
733
734 valid = padata_validate_cpumask(pinst, pcpumask);
735 if (!valid) {
736 __padata_stop(pinst);
737 goto out_replace;
738 }
739
740 valid = padata_validate_cpumask(pinst, cbcpumask);
741 if (!valid)
742 __padata_stop(pinst);
743
744out_replace:
745 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
746 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
747
748 err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst);
749
750 if (valid)
751 __padata_start(pinst);
752
753 return err;
754}
755
756/**
757 * padata_set_cpumask - Sets specified by @cpumask_type cpumask to the value
758 * equivalent to @cpumask.
759 * @pinst: padata instance
760 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
761 * to parallel and serial cpumasks respectively.
762 * @cpumask: the cpumask to use
763 *
764 * Return: 0 on success or negative error code
765 */
766int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
767 cpumask_var_t cpumask)
768{
769 struct cpumask *serial_mask, *parallel_mask;
770 int err = -EINVAL;
771
772 cpus_read_lock();
773 mutex_lock(&pinst->lock);
774
775 switch (cpumask_type) {
776 case PADATA_CPU_PARALLEL:
777 serial_mask = pinst->cpumask.cbcpu;
778 parallel_mask = cpumask;
779 break;
780 case PADATA_CPU_SERIAL:
781 parallel_mask = pinst->cpumask.pcpu;
782 serial_mask = cpumask;
783 break;
784 default:
785 goto out;
786 }
787
788 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
789
790out:
791 mutex_unlock(&pinst->lock);
792 cpus_read_unlock();
793
794 return err;
795}
796EXPORT_SYMBOL(padata_set_cpumask);
797
798#ifdef CONFIG_HOTPLUG_CPU
799
800static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
801{
802 int err = 0;
803
804 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
805 err = padata_replace(pinst);
806
807 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
808 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
809 __padata_start(pinst);
810 }
811
812 return err;
813}
814
815static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
816{
817 int err = 0;
818
819 if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
820 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
821 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
822 __padata_stop(pinst);
823
824 err = padata_replace(pinst);
825 }
826
827 return err;
828}
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
836static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
837{
838 struct padata_instance *pinst;
839 int ret;
840
841 pinst = hlist_entry_safe(node, struct padata_instance, cpu_online_node);
842 if (!pinst_has_cpu(pinst, cpu))
843 return 0;
844
845 mutex_lock(&pinst->lock);
846 ret = __padata_add_cpu(pinst, cpu);
847 mutex_unlock(&pinst->lock);
848 return ret;
849}
850
851static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node)
852{
853 struct padata_instance *pinst;
854 int ret;
855
856 pinst = hlist_entry_safe(node, struct padata_instance, cpu_dead_node);
857 if (!pinst_has_cpu(pinst, cpu))
858 return 0;
859
860 mutex_lock(&pinst->lock);
861 ret = __padata_remove_cpu(pinst, cpu);
862 mutex_unlock(&pinst->lock);
863 return ret;
864}
865
866static enum cpuhp_state hp_online;
867#endif
868
869static void __padata_free(struct padata_instance *pinst)
870{
871#ifdef CONFIG_HOTPLUG_CPU
872 cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD,
873 &pinst->cpu_dead_node);
874 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->cpu_online_node);
875#endif
876
877 WARN_ON(!list_empty(&pinst->pslist));
878
879 free_cpumask_var(pinst->cpumask.pcpu);
880 free_cpumask_var(pinst->cpumask.cbcpu);
881 destroy_workqueue(pinst->serial_wq);
882 destroy_workqueue(pinst->parallel_wq);
883 kfree(pinst);
884}
885
886#define kobj2pinst(_kobj) \
887 container_of(_kobj, struct padata_instance, kobj)
888#define attr2pentry(_attr) \
889 container_of(_attr, struct padata_sysfs_entry, attr)
890
891static void padata_sysfs_release(struct kobject *kobj)
892{
893 struct padata_instance *pinst = kobj2pinst(kobj);
894 __padata_free(pinst);
895}
896
897struct padata_sysfs_entry {
898 struct attribute attr;
899 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
900 ssize_t (*store)(struct padata_instance *, struct attribute *,
901 const char *, size_t);
902};
903
904static ssize_t show_cpumask(struct padata_instance *pinst,
905 struct attribute *attr, char *buf)
906{
907 struct cpumask *cpumask;
908 ssize_t len;
909
910 mutex_lock(&pinst->lock);
911 if (!strcmp(attr->name, "serial_cpumask"))
912 cpumask = pinst->cpumask.cbcpu;
913 else
914 cpumask = pinst->cpumask.pcpu;
915
916 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
917 nr_cpu_ids, cpumask_bits(cpumask));
918 mutex_unlock(&pinst->lock);
919 return len < PAGE_SIZE ? len : -EINVAL;
920}
921
922static ssize_t store_cpumask(struct padata_instance *pinst,
923 struct attribute *attr,
924 const char *buf, size_t count)
925{
926 cpumask_var_t new_cpumask;
927 ssize_t ret;
928 int mask_type;
929
930 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
931 return -ENOMEM;
932
933 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
934 nr_cpumask_bits);
935 if (ret < 0)
936 goto out;
937
938 mask_type = !strcmp(attr->name, "serial_cpumask") ?
939 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
940 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
941 if (!ret)
942 ret = count;
943
944out:
945 free_cpumask_var(new_cpumask);
946 return ret;
947}
948
949#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
950 static struct padata_sysfs_entry _name##_attr = \
951 __ATTR(_name, 0644, _show_name, _store_name)
952#define PADATA_ATTR_RO(_name, _show_name) \
953 static struct padata_sysfs_entry _name##_attr = \
954 __ATTR(_name, 0400, _show_name, NULL)
955
956PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
957PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
958
959/*
960 * Padata sysfs provides the following objects:
961 * serial_cpumask [RW] - cpumask for serial workers
962 * parallel_cpumask [RW] - cpumask for parallel workers
963 */
964static struct attribute *padata_default_attrs[] = {
965 &serial_cpumask_attr.attr,
966 ¶llel_cpumask_attr.attr,
967 NULL,
968};
969ATTRIBUTE_GROUPS(padata_default);
970
971static ssize_t padata_sysfs_show(struct kobject *kobj,
972 struct attribute *attr, char *buf)
973{
974 struct padata_instance *pinst;
975 struct padata_sysfs_entry *pentry;
976 ssize_t ret = -EIO;
977
978 pinst = kobj2pinst(kobj);
979 pentry = attr2pentry(attr);
980 if (pentry->show)
981 ret = pentry->show(pinst, attr, buf);
982
983 return ret;
984}
985
986static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
987 const char *buf, size_t count)
988{
989 struct padata_instance *pinst;
990 struct padata_sysfs_entry *pentry;
991 ssize_t ret = -EIO;
992
993 pinst = kobj2pinst(kobj);
994 pentry = attr2pentry(attr);
995 if (pentry->store)
996 ret = pentry->store(pinst, attr, buf, count);
997
998 return ret;
999}
1000
1001static const struct sysfs_ops padata_sysfs_ops = {
1002 .show = padata_sysfs_show,
1003 .store = padata_sysfs_store,
1004};
1005
1006static const struct kobj_type padata_attr_type = {
1007 .sysfs_ops = &padata_sysfs_ops,
1008 .default_groups = padata_default_groups,
1009 .release = padata_sysfs_release,
1010};
1011
1012/**
1013 * padata_alloc - allocate and initialize a padata instance
1014 * @name: used to identify the instance
1015 *
1016 * Return: new instance on success, NULL on error
1017 */
1018struct padata_instance *padata_alloc(const char *name)
1019{
1020 struct padata_instance *pinst;
1021
1022 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1023 if (!pinst)
1024 goto err;
1025
1026 pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
1027 name);
1028 if (!pinst->parallel_wq)
1029 goto err_free_inst;
1030
1031 cpus_read_lock();
1032
1033 pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
1034 WQ_CPU_INTENSIVE, 1, name);
1035 if (!pinst->serial_wq)
1036 goto err_put_cpus;
1037
1038 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1039 goto err_free_serial_wq;
1040 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1041 free_cpumask_var(pinst->cpumask.pcpu);
1042 goto err_free_serial_wq;
1043 }
1044
1045 INIT_LIST_HEAD(&pinst->pslist);
1046
1047 cpumask_copy(pinst->cpumask.pcpu, cpu_possible_mask);
1048 cpumask_copy(pinst->cpumask.cbcpu, cpu_possible_mask);
1049
1050 if (padata_setup_cpumasks(pinst))
1051 goto err_free_masks;
1052
1053 __padata_start(pinst);
1054
1055 kobject_init(&pinst->kobj, &padata_attr_type);
1056 mutex_init(&pinst->lock);
1057
1058#ifdef CONFIG_HOTPLUG_CPU
1059 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online,
1060 &pinst->cpu_online_node);
1061 cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
1062 &pinst->cpu_dead_node);
1063#endif
1064
1065 cpus_read_unlock();
1066
1067 return pinst;
1068
1069err_free_masks:
1070 free_cpumask_var(pinst->cpumask.pcpu);
1071 free_cpumask_var(pinst->cpumask.cbcpu);
1072err_free_serial_wq:
1073 destroy_workqueue(pinst->serial_wq);
1074err_put_cpus:
1075 cpus_read_unlock();
1076 destroy_workqueue(pinst->parallel_wq);
1077err_free_inst:
1078 kfree(pinst);
1079err:
1080 return NULL;
1081}
1082EXPORT_SYMBOL(padata_alloc);
1083
1084/**
1085 * padata_free - free a padata instance
1086 *
1087 * @pinst: padata instance to free
1088 */
1089void padata_free(struct padata_instance *pinst)
1090{
1091 kobject_put(&pinst->kobj);
1092}
1093EXPORT_SYMBOL(padata_free);
1094
1095/**
1096 * padata_alloc_shell - Allocate and initialize padata shell.
1097 *
1098 * @pinst: Parent padata_instance object.
1099 *
1100 * Return: new shell on success, NULL on error
1101 */
1102struct padata_shell *padata_alloc_shell(struct padata_instance *pinst)
1103{
1104 struct parallel_data *pd;
1105 struct padata_shell *ps;
1106
1107 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1108 if (!ps)
1109 goto out;
1110
1111 ps->pinst = pinst;
1112
1113 cpus_read_lock();
1114 pd = padata_alloc_pd(ps);
1115 cpus_read_unlock();
1116
1117 if (!pd)
1118 goto out_free_ps;
1119
1120 mutex_lock(&pinst->lock);
1121 RCU_INIT_POINTER(ps->pd, pd);
1122 list_add(&ps->list, &pinst->pslist);
1123 mutex_unlock(&pinst->lock);
1124
1125 return ps;
1126
1127out_free_ps:
1128 kfree(ps);
1129out:
1130 return NULL;
1131}
1132EXPORT_SYMBOL(padata_alloc_shell);
1133
1134/**
1135 * padata_free_shell - free a padata shell
1136 *
1137 * @ps: padata shell to free
1138 */
1139void padata_free_shell(struct padata_shell *ps)
1140{
1141 struct parallel_data *pd;
1142
1143 if (!ps)
1144 return;
1145
1146 /*
1147 * Wait for all _do_serial calls to finish to avoid touching
1148 * freed pd's and ps's.
1149 */
1150 synchronize_rcu();
1151
1152 mutex_lock(&ps->pinst->lock);
1153 list_del(&ps->list);
1154 pd = rcu_dereference_protected(ps->pd, 1);
1155 padata_put_pd(pd);
1156 mutex_unlock(&ps->pinst->lock);
1157
1158 kfree(ps);
1159}
1160EXPORT_SYMBOL(padata_free_shell);
1161
1162void __init padata_init(void)
1163{
1164 unsigned int i, possible_cpus;
1165#ifdef CONFIG_HOTPLUG_CPU
1166 int ret;
1167
1168 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1169 padata_cpu_online, NULL);
1170 if (ret < 0)
1171 goto err;
1172 hp_online = ret;
1173
1174 ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead",
1175 NULL, padata_cpu_dead);
1176 if (ret < 0)
1177 goto remove_online_state;
1178#endif
1179
1180 possible_cpus = num_possible_cpus();
1181 padata_works = kmalloc_array(possible_cpus, sizeof(struct padata_work),
1182 GFP_KERNEL);
1183 if (!padata_works)
1184 goto remove_dead_state;
1185
1186 for (i = 0; i < possible_cpus; ++i)
1187 list_add(&padata_works[i].pw_list, &padata_free_works);
1188
1189 return;
1190
1191remove_dead_state:
1192#ifdef CONFIG_HOTPLUG_CPU
1193 cpuhp_remove_multi_state(CPUHP_PADATA_DEAD);
1194remove_online_state:
1195 cpuhp_remove_multi_state(hp_online);
1196err:
1197#endif
1198 pr_warn("padata: initialization failed\n");
1199}
1/*
2 * padata.c - generic interface to process data streams in parallel
3 *
4 * Copyright (C) 2008, 2009 secunet Security Networks AG
5 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21#include <linux/module.h>
22#include <linux/cpumask.h>
23#include <linux/err.h>
24#include <linux/cpu.h>
25#include <linux/padata.h>
26#include <linux/mutex.h>
27#include <linux/sched.h>
28#include <linux/slab.h>
29#include <linux/sysfs.h>
30#include <linux/rcupdate.h>
31
32#define MAX_SEQ_NR (INT_MAX - NR_CPUS)
33#define MAX_OBJ_NUM 1000
34
35static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
36{
37 int cpu, target_cpu;
38
39 target_cpu = cpumask_first(pd->cpumask.pcpu);
40 for (cpu = 0; cpu < cpu_index; cpu++)
41 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
42
43 return target_cpu;
44}
45
46static int padata_cpu_hash(struct padata_priv *padata)
47{
48 int cpu_index;
49 struct parallel_data *pd;
50
51 pd = padata->pd;
52
53 /*
54 * Hash the sequence numbers to the cpus by taking
55 * seq_nr mod. number of cpus in use.
56 */
57 cpu_index = padata->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 struct parallel_data *pd;
66 struct padata_instance *pinst;
67 LIST_HEAD(local_list);
68
69 local_bh_disable();
70 pqueue = container_of(parallel_work,
71 struct padata_parallel_queue, work);
72 pd = pqueue->pd;
73 pinst = pd->pinst;
74
75 spin_lock(&pqueue->parallel.lock);
76 list_replace_init(&pqueue->parallel.list, &local_list);
77 spin_unlock(&pqueue->parallel.lock);
78
79 while (!list_empty(&local_list)) {
80 struct padata_priv *padata;
81
82 padata = list_entry(local_list.next,
83 struct padata_priv, list);
84
85 list_del_init(&padata->list);
86
87 padata->parallel(padata);
88 }
89
90 local_bh_enable();
91}
92
93/**
94 * padata_do_parallel - padata parallelization function
95 *
96 * @pinst: padata instance
97 * @padata: object to be parallelized
98 * @cb_cpu: cpu the serialization callback function will run on,
99 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
100 *
101 * The parallelization callback function will run with BHs off.
102 * Note: Every object which is parallelized by padata_do_parallel
103 * must be seen by padata_do_serial.
104 */
105int padata_do_parallel(struct padata_instance *pinst,
106 struct padata_priv *padata, int cb_cpu)
107{
108 int target_cpu, err;
109 struct padata_parallel_queue *queue;
110 struct parallel_data *pd;
111
112 rcu_read_lock_bh();
113
114 pd = rcu_dereference(pinst->pd);
115
116 err = -EINVAL;
117 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
118 goto out;
119
120 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
121 goto out;
122
123 err = -EBUSY;
124 if ((pinst->flags & PADATA_RESET))
125 goto out;
126
127 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
128 goto out;
129
130 err = 0;
131 atomic_inc(&pd->refcnt);
132 padata->pd = pd;
133 padata->cb_cpu = cb_cpu;
134
135 if (unlikely(atomic_read(&pd->seq_nr) == pd->max_seq_nr))
136 atomic_set(&pd->seq_nr, -1);
137
138 padata->seq_nr = atomic_inc_return(&pd->seq_nr);
139
140 target_cpu = padata_cpu_hash(padata);
141 queue = per_cpu_ptr(pd->pqueue, target_cpu);
142
143 spin_lock(&queue->parallel.lock);
144 list_add_tail(&padata->list, &queue->parallel.list);
145 spin_unlock(&queue->parallel.lock);
146
147 queue_work_on(target_cpu, pinst->wq, &queue->work);
148
149out:
150 rcu_read_unlock_bh();
151
152 return err;
153}
154EXPORT_SYMBOL(padata_do_parallel);
155
156/*
157 * padata_get_next - Get the next object that needs serialization.
158 *
159 * Return values are:
160 *
161 * A pointer to the control struct of the next object that needs
162 * serialization, if present in one of the percpu reorder queues.
163 *
164 * NULL, if all percpu reorder queues are empty.
165 *
166 * -EINPROGRESS, if the next object that needs serialization will
167 * be parallel processed by another cpu and is not yet present in
168 * the cpu's reorder queue.
169 *
170 * -ENODATA, if this cpu has to do the parallel processing for
171 * the next object.
172 */
173static struct padata_priv *padata_get_next(struct parallel_data *pd)
174{
175 int cpu, num_cpus;
176 int next_nr, next_index;
177 struct padata_parallel_queue *queue, *next_queue;
178 struct padata_priv *padata;
179 struct padata_list *reorder;
180
181 num_cpus = cpumask_weight(pd->cpumask.pcpu);
182
183 /*
184 * Calculate the percpu reorder queue and the sequence
185 * number of the next object.
186 */
187 next_nr = pd->processed;
188 next_index = next_nr % num_cpus;
189 cpu = padata_index_to_cpu(pd, next_index);
190 next_queue = per_cpu_ptr(pd->pqueue, cpu);
191
192 if (unlikely(next_nr > pd->max_seq_nr)) {
193 next_nr = next_nr - pd->max_seq_nr - 1;
194 next_index = next_nr % num_cpus;
195 cpu = padata_index_to_cpu(pd, next_index);
196 next_queue = per_cpu_ptr(pd->pqueue, cpu);
197 pd->processed = 0;
198 }
199
200 padata = NULL;
201
202 reorder = &next_queue->reorder;
203
204 if (!list_empty(&reorder->list)) {
205 padata = list_entry(reorder->list.next,
206 struct padata_priv, list);
207
208 BUG_ON(next_nr != padata->seq_nr);
209
210 spin_lock(&reorder->lock);
211 list_del_init(&padata->list);
212 atomic_dec(&pd->reorder_objects);
213 spin_unlock(&reorder->lock);
214
215 pd->processed++;
216
217 goto out;
218 }
219
220 queue = per_cpu_ptr(pd->pqueue, smp_processor_id());
221 if (queue->cpu_index == next_queue->cpu_index) {
222 padata = ERR_PTR(-ENODATA);
223 goto out;
224 }
225
226 padata = ERR_PTR(-EINPROGRESS);
227out:
228 return padata;
229}
230
231static void padata_reorder(struct parallel_data *pd)
232{
233 struct padata_priv *padata;
234 struct padata_serial_queue *squeue;
235 struct padata_instance *pinst = pd->pinst;
236
237 /*
238 * We need to ensure that only one cpu can work on dequeueing of
239 * the reorder queue the time. Calculating in which percpu reorder
240 * queue the next object will arrive takes some time. A spinlock
241 * would be highly contended. Also it is not clear in which order
242 * the objects arrive to the reorder queues. So a cpu could wait to
243 * get the lock just to notice that there is nothing to do at the
244 * moment. Therefore we use a trylock and let the holder of the lock
245 * care for all the objects enqueued during the holdtime of the lock.
246 */
247 if (!spin_trylock_bh(&pd->lock))
248 return;
249
250 while (1) {
251 padata = padata_get_next(pd);
252
253 /*
254 * All reorder queues are empty, or the next object that needs
255 * serialization is parallel processed by another cpu and is
256 * still on it's way to the cpu's reorder queue, nothing to
257 * do for now.
258 */
259 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
260 break;
261
262 /*
263 * This cpu has to do the parallel processing of the next
264 * object. It's waiting in the cpu's parallelization queue,
265 * so exit immediately.
266 */
267 if (PTR_ERR(padata) == -ENODATA) {
268 del_timer(&pd->timer);
269 spin_unlock_bh(&pd->lock);
270 return;
271 }
272
273 squeue = per_cpu_ptr(pd->squeue, padata->cb_cpu);
274
275 spin_lock(&squeue->serial.lock);
276 list_add_tail(&padata->list, &squeue->serial.list);
277 spin_unlock(&squeue->serial.lock);
278
279 queue_work_on(padata->cb_cpu, pinst->wq, &squeue->work);
280 }
281
282 spin_unlock_bh(&pd->lock);
283
284 /*
285 * The next object that needs serialization might have arrived to
286 * the reorder queues in the meantime, we will be called again
287 * from the timer function if no one else cares for it.
288 */
289 if (atomic_read(&pd->reorder_objects)
290 && !(pinst->flags & PADATA_RESET))
291 mod_timer(&pd->timer, jiffies + HZ);
292 else
293 del_timer(&pd->timer);
294
295 return;
296}
297
298static void padata_reorder_timer(unsigned long arg)
299{
300 struct parallel_data *pd = (struct parallel_data *)arg;
301
302 padata_reorder(pd);
303}
304
305static void padata_serial_worker(struct work_struct *serial_work)
306{
307 struct padata_serial_queue *squeue;
308 struct parallel_data *pd;
309 LIST_HEAD(local_list);
310
311 local_bh_disable();
312 squeue = container_of(serial_work, struct padata_serial_queue, work);
313 pd = squeue->pd;
314
315 spin_lock(&squeue->serial.lock);
316 list_replace_init(&squeue->serial.list, &local_list);
317 spin_unlock(&squeue->serial.lock);
318
319 while (!list_empty(&local_list)) {
320 struct padata_priv *padata;
321
322 padata = list_entry(local_list.next,
323 struct padata_priv, list);
324
325 list_del_init(&padata->list);
326
327 padata->serial(padata);
328 atomic_dec(&pd->refcnt);
329 }
330 local_bh_enable();
331}
332
333/**
334 * padata_do_serial - padata serialization function
335 *
336 * @padata: object to be serialized.
337 *
338 * padata_do_serial must be called for every parallelized object.
339 * The serialization callback function will run with BHs off.
340 */
341void padata_do_serial(struct padata_priv *padata)
342{
343 int cpu;
344 struct padata_parallel_queue *pqueue;
345 struct parallel_data *pd;
346
347 pd = padata->pd;
348
349 cpu = get_cpu();
350 pqueue = per_cpu_ptr(pd->pqueue, cpu);
351
352 spin_lock(&pqueue->reorder.lock);
353 atomic_inc(&pd->reorder_objects);
354 list_add_tail(&padata->list, &pqueue->reorder.list);
355 spin_unlock(&pqueue->reorder.lock);
356
357 put_cpu();
358
359 padata_reorder(pd);
360}
361EXPORT_SYMBOL(padata_do_serial);
362
363static int padata_setup_cpumasks(struct parallel_data *pd,
364 const struct cpumask *pcpumask,
365 const struct cpumask *cbcpumask)
366{
367 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
368 return -ENOMEM;
369
370 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_active_mask);
371 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
372 free_cpumask_var(pd->cpumask.cbcpu);
373 return -ENOMEM;
374 }
375
376 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_active_mask);
377 return 0;
378}
379
380static void __padata_list_init(struct padata_list *pd_list)
381{
382 INIT_LIST_HEAD(&pd_list->list);
383 spin_lock_init(&pd_list->lock);
384}
385
386/* Initialize all percpu queues used by serial workers */
387static void padata_init_squeues(struct parallel_data *pd)
388{
389 int cpu;
390 struct padata_serial_queue *squeue;
391
392 for_each_cpu(cpu, pd->cpumask.cbcpu) {
393 squeue = per_cpu_ptr(pd->squeue, cpu);
394 squeue->pd = pd;
395 __padata_list_init(&squeue->serial);
396 INIT_WORK(&squeue->work, padata_serial_worker);
397 }
398}
399
400/* Initialize all percpu queues used by parallel workers */
401static void padata_init_pqueues(struct parallel_data *pd)
402{
403 int cpu_index, num_cpus, cpu;
404 struct padata_parallel_queue *pqueue;
405
406 cpu_index = 0;
407 for_each_cpu(cpu, pd->cpumask.pcpu) {
408 pqueue = per_cpu_ptr(pd->pqueue, cpu);
409 pqueue->pd = pd;
410 pqueue->cpu_index = cpu_index;
411 cpu_index++;
412
413 __padata_list_init(&pqueue->reorder);
414 __padata_list_init(&pqueue->parallel);
415 INIT_WORK(&pqueue->work, padata_parallel_worker);
416 atomic_set(&pqueue->num_obj, 0);
417 }
418
419 num_cpus = cpumask_weight(pd->cpumask.pcpu);
420 pd->max_seq_nr = num_cpus ? (MAX_SEQ_NR / num_cpus) * num_cpus - 1 : 0;
421}
422
423/* Allocate and initialize the internal cpumask dependend resources. */
424static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
425 const struct cpumask *pcpumask,
426 const struct cpumask *cbcpumask)
427{
428 struct parallel_data *pd;
429
430 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
431 if (!pd)
432 goto err;
433
434 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
435 if (!pd->pqueue)
436 goto err_free_pd;
437
438 pd->squeue = alloc_percpu(struct padata_serial_queue);
439 if (!pd->squeue)
440 goto err_free_pqueue;
441 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
442 goto err_free_squeue;
443
444 padata_init_pqueues(pd);
445 padata_init_squeues(pd);
446 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
447 atomic_set(&pd->seq_nr, -1);
448 atomic_set(&pd->reorder_objects, 0);
449 atomic_set(&pd->refcnt, 0);
450 pd->pinst = pinst;
451 spin_lock_init(&pd->lock);
452
453 return pd;
454
455err_free_squeue:
456 free_percpu(pd->squeue);
457err_free_pqueue:
458 free_percpu(pd->pqueue);
459err_free_pd:
460 kfree(pd);
461err:
462 return NULL;
463}
464
465static void padata_free_pd(struct parallel_data *pd)
466{
467 free_cpumask_var(pd->cpumask.pcpu);
468 free_cpumask_var(pd->cpumask.cbcpu);
469 free_percpu(pd->pqueue);
470 free_percpu(pd->squeue);
471 kfree(pd);
472}
473
474/* Flush all objects out of the padata queues. */
475static void padata_flush_queues(struct parallel_data *pd)
476{
477 int cpu;
478 struct padata_parallel_queue *pqueue;
479 struct padata_serial_queue *squeue;
480
481 for_each_cpu(cpu, pd->cpumask.pcpu) {
482 pqueue = per_cpu_ptr(pd->pqueue, cpu);
483 flush_work(&pqueue->work);
484 }
485
486 del_timer_sync(&pd->timer);
487
488 if (atomic_read(&pd->reorder_objects))
489 padata_reorder(pd);
490
491 for_each_cpu(cpu, pd->cpumask.cbcpu) {
492 squeue = per_cpu_ptr(pd->squeue, cpu);
493 flush_work(&squeue->work);
494 }
495
496 BUG_ON(atomic_read(&pd->refcnt) != 0);
497}
498
499static void __padata_start(struct padata_instance *pinst)
500{
501 pinst->flags |= PADATA_INIT;
502}
503
504static void __padata_stop(struct padata_instance *pinst)
505{
506 if (!(pinst->flags & PADATA_INIT))
507 return;
508
509 pinst->flags &= ~PADATA_INIT;
510
511 synchronize_rcu();
512
513 get_online_cpus();
514 padata_flush_queues(pinst->pd);
515 put_online_cpus();
516}
517
518/* Replace the internal control structure with a new one. */
519static void padata_replace(struct padata_instance *pinst,
520 struct parallel_data *pd_new)
521{
522 struct parallel_data *pd_old = pinst->pd;
523 int notification_mask = 0;
524
525 pinst->flags |= PADATA_RESET;
526
527 rcu_assign_pointer(pinst->pd, pd_new);
528
529 synchronize_rcu();
530
531 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
532 notification_mask |= PADATA_CPU_PARALLEL;
533 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
534 notification_mask |= PADATA_CPU_SERIAL;
535
536 padata_flush_queues(pd_old);
537 padata_free_pd(pd_old);
538
539 if (notification_mask)
540 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
541 notification_mask,
542 &pd_new->cpumask);
543
544 pinst->flags &= ~PADATA_RESET;
545}
546
547/**
548 * padata_register_cpumask_notifier - Registers a notifier that will be called
549 * if either pcpu or cbcpu or both cpumasks change.
550 *
551 * @pinst: A poineter to padata instance
552 * @nblock: A pointer to notifier block.
553 */
554int padata_register_cpumask_notifier(struct padata_instance *pinst,
555 struct notifier_block *nblock)
556{
557 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
558 nblock);
559}
560EXPORT_SYMBOL(padata_register_cpumask_notifier);
561
562/**
563 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
564 * registered earlier using padata_register_cpumask_notifier
565 *
566 * @pinst: A pointer to data instance.
567 * @nlock: A pointer to notifier block.
568 */
569int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
570 struct notifier_block *nblock)
571{
572 return blocking_notifier_chain_unregister(
573 &pinst->cpumask_change_notifier,
574 nblock);
575}
576EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
577
578
579/* If cpumask contains no active cpu, we mark the instance as invalid. */
580static bool padata_validate_cpumask(struct padata_instance *pinst,
581 const struct cpumask *cpumask)
582{
583 if (!cpumask_intersects(cpumask, cpu_active_mask)) {
584 pinst->flags |= PADATA_INVALID;
585 return false;
586 }
587
588 pinst->flags &= ~PADATA_INVALID;
589 return true;
590}
591
592static int __padata_set_cpumasks(struct padata_instance *pinst,
593 cpumask_var_t pcpumask,
594 cpumask_var_t cbcpumask)
595{
596 int valid;
597 struct parallel_data *pd;
598
599 valid = padata_validate_cpumask(pinst, pcpumask);
600 if (!valid) {
601 __padata_stop(pinst);
602 goto out_replace;
603 }
604
605 valid = padata_validate_cpumask(pinst, cbcpumask);
606 if (!valid)
607 __padata_stop(pinst);
608
609out_replace:
610 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
611 if (!pd)
612 return -ENOMEM;
613
614 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
615 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
616
617 padata_replace(pinst, pd);
618
619 if (valid)
620 __padata_start(pinst);
621
622 return 0;
623}
624
625/**
626 * padata_set_cpumasks - Set both parallel and serial cpumasks. The first
627 * one is used by parallel workers and the second one
628 * by the wokers doing serialization.
629 *
630 * @pinst: padata instance
631 * @pcpumask: the cpumask to use for parallel workers
632 * @cbcpumask: the cpumsak to use for serial workers
633 */
634int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
635 cpumask_var_t cbcpumask)
636{
637 int err;
638
639 mutex_lock(&pinst->lock);
640 get_online_cpus();
641
642 err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
643
644 put_online_cpus();
645 mutex_unlock(&pinst->lock);
646
647 return err;
648
649}
650EXPORT_SYMBOL(padata_set_cpumasks);
651
652/**
653 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
654 * equivalent to @cpumask.
655 *
656 * @pinst: padata instance
657 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
658 * to parallel and serial cpumasks respectively.
659 * @cpumask: the cpumask to use
660 */
661int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
662 cpumask_var_t cpumask)
663{
664 struct cpumask *serial_mask, *parallel_mask;
665 int err = -EINVAL;
666
667 mutex_lock(&pinst->lock);
668 get_online_cpus();
669
670 switch (cpumask_type) {
671 case PADATA_CPU_PARALLEL:
672 serial_mask = pinst->cpumask.cbcpu;
673 parallel_mask = cpumask;
674 break;
675 case PADATA_CPU_SERIAL:
676 parallel_mask = pinst->cpumask.pcpu;
677 serial_mask = cpumask;
678 break;
679 default:
680 goto out;
681 }
682
683 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
684
685out:
686 put_online_cpus();
687 mutex_unlock(&pinst->lock);
688
689 return err;
690}
691EXPORT_SYMBOL(padata_set_cpumask);
692
693static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
694{
695 struct parallel_data *pd;
696
697 if (cpumask_test_cpu(cpu, cpu_active_mask)) {
698 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
699 pinst->cpumask.cbcpu);
700 if (!pd)
701 return -ENOMEM;
702
703 padata_replace(pinst, pd);
704
705 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
706 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
707 __padata_start(pinst);
708 }
709
710 return 0;
711}
712
713 /**
714 * padata_add_cpu - add a cpu to one or both(parallel and serial)
715 * padata cpumasks.
716 *
717 * @pinst: padata instance
718 * @cpu: cpu to add
719 * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
720 * The @mask may be any combination of the following flags:
721 * PADATA_CPU_SERIAL - serial cpumask
722 * PADATA_CPU_PARALLEL - parallel cpumask
723 */
724
725int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask)
726{
727 int err;
728
729 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
730 return -EINVAL;
731
732 mutex_lock(&pinst->lock);
733
734 get_online_cpus();
735 if (mask & PADATA_CPU_SERIAL)
736 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu);
737 if (mask & PADATA_CPU_PARALLEL)
738 cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
739
740 err = __padata_add_cpu(pinst, cpu);
741 put_online_cpus();
742
743 mutex_unlock(&pinst->lock);
744
745 return err;
746}
747EXPORT_SYMBOL(padata_add_cpu);
748
749static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
750{
751 struct parallel_data *pd = NULL;
752
753 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
754
755 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
756 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
757 __padata_stop(pinst);
758
759 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
760 pinst->cpumask.cbcpu);
761 if (!pd)
762 return -ENOMEM;
763
764 padata_replace(pinst, pd);
765 }
766
767 return 0;
768}
769
770 /**
771 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
772 * padata cpumasks.
773 *
774 * @pinst: padata instance
775 * @cpu: cpu to remove
776 * @mask: bitmask specifying from which cpumask @cpu should be removed
777 * The @mask may be any combination of the following flags:
778 * PADATA_CPU_SERIAL - serial cpumask
779 * PADATA_CPU_PARALLEL - parallel cpumask
780 */
781int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
782{
783 int err;
784
785 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
786 return -EINVAL;
787
788 mutex_lock(&pinst->lock);
789
790 get_online_cpus();
791 if (mask & PADATA_CPU_SERIAL)
792 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
793 if (mask & PADATA_CPU_PARALLEL)
794 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
795
796 err = __padata_remove_cpu(pinst, cpu);
797 put_online_cpus();
798
799 mutex_unlock(&pinst->lock);
800
801 return err;
802}
803EXPORT_SYMBOL(padata_remove_cpu);
804
805/**
806 * padata_start - start the parallel processing
807 *
808 * @pinst: padata instance to start
809 */
810int padata_start(struct padata_instance *pinst)
811{
812 int err = 0;
813
814 mutex_lock(&pinst->lock);
815
816 if (pinst->flags & PADATA_INVALID)
817 err =-EINVAL;
818
819 __padata_start(pinst);
820
821 mutex_unlock(&pinst->lock);
822
823 return err;
824}
825EXPORT_SYMBOL(padata_start);
826
827/**
828 * padata_stop - stop the parallel processing
829 *
830 * @pinst: padata instance to stop
831 */
832void padata_stop(struct padata_instance *pinst)
833{
834 mutex_lock(&pinst->lock);
835 __padata_stop(pinst);
836 mutex_unlock(&pinst->lock);
837}
838EXPORT_SYMBOL(padata_stop);
839
840#ifdef CONFIG_HOTPLUG_CPU
841
842static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
843{
844 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
845 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
846}
847
848
849static int padata_cpu_callback(struct notifier_block *nfb,
850 unsigned long action, void *hcpu)
851{
852 int err;
853 struct padata_instance *pinst;
854 int cpu = (unsigned long)hcpu;
855
856 pinst = container_of(nfb, struct padata_instance, cpu_notifier);
857
858 switch (action) {
859 case CPU_ONLINE:
860 case CPU_ONLINE_FROZEN:
861 if (!pinst_has_cpu(pinst, cpu))
862 break;
863 mutex_lock(&pinst->lock);
864 err = __padata_add_cpu(pinst, cpu);
865 mutex_unlock(&pinst->lock);
866 if (err)
867 return notifier_from_errno(err);
868 break;
869
870 case CPU_DOWN_PREPARE:
871 case CPU_DOWN_PREPARE_FROZEN:
872 if (!pinst_has_cpu(pinst, cpu))
873 break;
874 mutex_lock(&pinst->lock);
875 err = __padata_remove_cpu(pinst, cpu);
876 mutex_unlock(&pinst->lock);
877 if (err)
878 return notifier_from_errno(err);
879 break;
880
881 case CPU_UP_CANCELED:
882 case CPU_UP_CANCELED_FROZEN:
883 if (!pinst_has_cpu(pinst, cpu))
884 break;
885 mutex_lock(&pinst->lock);
886 __padata_remove_cpu(pinst, cpu);
887 mutex_unlock(&pinst->lock);
888
889 case CPU_DOWN_FAILED:
890 case CPU_DOWN_FAILED_FROZEN:
891 if (!pinst_has_cpu(pinst, cpu))
892 break;
893 mutex_lock(&pinst->lock);
894 __padata_add_cpu(pinst, cpu);
895 mutex_unlock(&pinst->lock);
896 }
897
898 return NOTIFY_OK;
899}
900#endif
901
902static void __padata_free(struct padata_instance *pinst)
903{
904#ifdef CONFIG_HOTPLUG_CPU
905 unregister_hotcpu_notifier(&pinst->cpu_notifier);
906#endif
907
908 padata_stop(pinst);
909 padata_free_pd(pinst->pd);
910 free_cpumask_var(pinst->cpumask.pcpu);
911 free_cpumask_var(pinst->cpumask.cbcpu);
912 kfree(pinst);
913}
914
915#define kobj2pinst(_kobj) \
916 container_of(_kobj, struct padata_instance, kobj)
917#define attr2pentry(_attr) \
918 container_of(_attr, struct padata_sysfs_entry, attr)
919
920static void padata_sysfs_release(struct kobject *kobj)
921{
922 struct padata_instance *pinst = kobj2pinst(kobj);
923 __padata_free(pinst);
924}
925
926struct padata_sysfs_entry {
927 struct attribute attr;
928 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
929 ssize_t (*store)(struct padata_instance *, struct attribute *,
930 const char *, size_t);
931};
932
933static ssize_t show_cpumask(struct padata_instance *pinst,
934 struct attribute *attr, char *buf)
935{
936 struct cpumask *cpumask;
937 ssize_t len;
938
939 mutex_lock(&pinst->lock);
940 if (!strcmp(attr->name, "serial_cpumask"))
941 cpumask = pinst->cpumask.cbcpu;
942 else
943 cpumask = pinst->cpumask.pcpu;
944
945 len = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask),
946 nr_cpu_ids);
947 if (PAGE_SIZE - len < 2)
948 len = -EINVAL;
949 else
950 len += sprintf(buf + len, "\n");
951
952 mutex_unlock(&pinst->lock);
953 return len;
954}
955
956static ssize_t store_cpumask(struct padata_instance *pinst,
957 struct attribute *attr,
958 const char *buf, size_t count)
959{
960 cpumask_var_t new_cpumask;
961 ssize_t ret;
962 int mask_type;
963
964 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
965 return -ENOMEM;
966
967 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
968 nr_cpumask_bits);
969 if (ret < 0)
970 goto out;
971
972 mask_type = !strcmp(attr->name, "serial_cpumask") ?
973 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
974 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
975 if (!ret)
976 ret = count;
977
978out:
979 free_cpumask_var(new_cpumask);
980 return ret;
981}
982
983#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
984 static struct padata_sysfs_entry _name##_attr = \
985 __ATTR(_name, 0644, _show_name, _store_name)
986#define PADATA_ATTR_RO(_name, _show_name) \
987 static struct padata_sysfs_entry _name##_attr = \
988 __ATTR(_name, 0400, _show_name, NULL)
989
990PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
991PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
992
993/*
994 * Padata sysfs provides the following objects:
995 * serial_cpumask [RW] - cpumask for serial workers
996 * parallel_cpumask [RW] - cpumask for parallel workers
997 */
998static struct attribute *padata_default_attrs[] = {
999 &serial_cpumask_attr.attr,
1000 ¶llel_cpumask_attr.attr,
1001 NULL,
1002};
1003
1004static ssize_t padata_sysfs_show(struct kobject *kobj,
1005 struct attribute *attr, char *buf)
1006{
1007 struct padata_instance *pinst;
1008 struct padata_sysfs_entry *pentry;
1009 ssize_t ret = -EIO;
1010
1011 pinst = kobj2pinst(kobj);
1012 pentry = attr2pentry(attr);
1013 if (pentry->show)
1014 ret = pentry->show(pinst, attr, buf);
1015
1016 return ret;
1017}
1018
1019static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
1020 const char *buf, size_t count)
1021{
1022 struct padata_instance *pinst;
1023 struct padata_sysfs_entry *pentry;
1024 ssize_t ret = -EIO;
1025
1026 pinst = kobj2pinst(kobj);
1027 pentry = attr2pentry(attr);
1028 if (pentry->show)
1029 ret = pentry->store(pinst, attr, buf, count);
1030
1031 return ret;
1032}
1033
1034static const struct sysfs_ops padata_sysfs_ops = {
1035 .show = padata_sysfs_show,
1036 .store = padata_sysfs_store,
1037};
1038
1039static struct kobj_type padata_attr_type = {
1040 .sysfs_ops = &padata_sysfs_ops,
1041 .default_attrs = padata_default_attrs,
1042 .release = padata_sysfs_release,
1043};
1044
1045/**
1046 * padata_alloc_possible - Allocate and initialize padata instance.
1047 * Use the cpu_possible_mask for serial and
1048 * parallel workers.
1049 *
1050 * @wq: workqueue to use for the allocated padata instance
1051 */
1052struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1053{
1054 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1055}
1056EXPORT_SYMBOL(padata_alloc_possible);
1057
1058/**
1059 * padata_alloc - allocate and initialize a padata instance and specify
1060 * cpumasks for serial and parallel workers.
1061 *
1062 * @wq: workqueue to use for the allocated padata instance
1063 * @pcpumask: cpumask that will be used for padata parallelization
1064 * @cbcpumask: cpumask that will be used for padata serialization
1065 */
1066struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1067 const struct cpumask *pcpumask,
1068 const struct cpumask *cbcpumask)
1069{
1070 struct padata_instance *pinst;
1071 struct parallel_data *pd = NULL;
1072
1073 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1074 if (!pinst)
1075 goto err;
1076
1077 get_online_cpus();
1078 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1079 goto err_free_inst;
1080 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1081 free_cpumask_var(pinst->cpumask.pcpu);
1082 goto err_free_inst;
1083 }
1084 if (!padata_validate_cpumask(pinst, pcpumask) ||
1085 !padata_validate_cpumask(pinst, cbcpumask))
1086 goto err_free_masks;
1087
1088 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1089 if (!pd)
1090 goto err_free_masks;
1091
1092 rcu_assign_pointer(pinst->pd, pd);
1093
1094 pinst->wq = wq;
1095
1096 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1097 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1098
1099 pinst->flags = 0;
1100
1101#ifdef CONFIG_HOTPLUG_CPU
1102 pinst->cpu_notifier.notifier_call = padata_cpu_callback;
1103 pinst->cpu_notifier.priority = 0;
1104 register_hotcpu_notifier(&pinst->cpu_notifier);
1105#endif
1106
1107 put_online_cpus();
1108
1109 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1110 kobject_init(&pinst->kobj, &padata_attr_type);
1111 mutex_init(&pinst->lock);
1112
1113 return pinst;
1114
1115err_free_masks:
1116 free_cpumask_var(pinst->cpumask.pcpu);
1117 free_cpumask_var(pinst->cpumask.cbcpu);
1118err_free_inst:
1119 kfree(pinst);
1120 put_online_cpus();
1121err:
1122 return NULL;
1123}
1124EXPORT_SYMBOL(padata_alloc);
1125
1126/**
1127 * padata_free - free a padata instance
1128 *
1129 * @padata_inst: padata instance to free
1130 */
1131void padata_free(struct padata_instance *pinst)
1132{
1133 kobject_put(&pinst->kobj);
1134}
1135EXPORT_SYMBOL(padata_free);