projects/linux·blob v6.13-rc5 · 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 * Copyright (c) 2020 Oracle and/or its affiliates.
11 * Author: Daniel Jordan <[email protected]>
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 int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
51{
52 int cpu, target_cpu;
53
54 target_cpu = cpumask_first(pd->cpumask.pcpu);
55 for (cpu = 0; cpu < cpu_index; cpu++)
56 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
57
58 return target_cpu;
59}
60
61static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
62{
63 /*
64 * Hash the sequence numbers to the cpus by taking
65 * seq_nr mod. number of cpus in use.
66 */
67 int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
68
69 return padata_index_to_cpu(pd, cpu_index);
70}
71
72static struct padata_work *padata_work_alloc(void)
73{
74 struct padata_work *pw;
75
76 lockdep_assert_held(&padata_works_lock);
77
78 if (list_empty(&padata_free_works))
79 return NULL; /* No more work items allowed to be queued. */
80
81 pw = list_first_entry(&padata_free_works, struct padata_work, pw_list);
82 list_del(&pw->pw_list);
83 return pw;
84}
85
86/*
87 * This function is marked __ref because this function may be optimized in such
88 * a way that it directly refers to work_fn's address, which causes modpost to
89 * complain when work_fn is marked __init. This scenario was observed with clang
90 * LTO, where padata_work_init() was optimized to refer directly to
91 * padata_mt_helper() because the calls to padata_work_init() with other work_fn
92 * values were eliminated or inlined.
93 */
94static void __ref padata_work_init(struct padata_work *pw, work_func_t work_fn,
95 void *data, int flags)
96{
97 if (flags & PADATA_WORK_ONSTACK)
98 INIT_WORK_ONSTACK(&pw->pw_work, work_fn);
99 else
100 INIT_WORK(&pw->pw_work, work_fn);
101 pw->pw_data = data;
102}
103
104static int __init padata_work_alloc_mt(int nworks, void *data,
105 struct list_head *head)
106{
107 int i;
108
109 spin_lock_bh(&padata_works_lock);
110 /* Start at 1 because the current task participates in the job. */
111 for (i = 1; i < nworks; ++i) {
112 struct padata_work *pw = padata_work_alloc();
113
114 if (!pw)
115 break;
116 padata_work_init(pw, padata_mt_helper, data, 0);
117 list_add(&pw->pw_list, head);
118 }
119 spin_unlock_bh(&padata_works_lock);
120
121 return i;
122}
123
124static void padata_work_free(struct padata_work *pw)
125{
126 lockdep_assert_held(&padata_works_lock);
127 list_add(&pw->pw_list, &padata_free_works);
128}
129
130static void __init padata_works_free(struct list_head *works)
131{
132 struct padata_work *cur, *next;
133
134 if (list_empty(works))
135 return;
136
137 spin_lock_bh(&padata_works_lock);
138 list_for_each_entry_safe(cur, next, works, pw_list) {
139 list_del(&cur->pw_list);
140 padata_work_free(cur);
141 }
142 spin_unlock_bh(&padata_works_lock);
143}
144
145static void padata_parallel_worker(struct work_struct *parallel_work)
146{
147 struct padata_work *pw = container_of(parallel_work, struct padata_work,
148 pw_work);
149 struct padata_priv *padata = pw->pw_data;
150
151 local_bh_disable();
152 padata->parallel(padata);
153 spin_lock(&padata_works_lock);
154 padata_work_free(pw);
155 spin_unlock(&padata_works_lock);
156 local_bh_enable();
157}
158
159/**
160 * padata_do_parallel - padata parallelization function
161 *
162 * @ps: padatashell
163 * @padata: object to be parallelized
164 * @cb_cpu: pointer to the CPU that the serialization callback function should
165 * run on. If it's not in the serial cpumask of @pinst
166 * (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
167 * none found, returns -EINVAL.
168 *
169 * The parallelization callback function will run with BHs off.
170 * Note: Every object which is parallelized by padata_do_parallel
171 * must be seen by padata_do_serial.
172 *
173 * Return: 0 on success or else negative error code.
174 */
175int padata_do_parallel(struct padata_shell *ps,
176 struct padata_priv *padata, int *cb_cpu)
177{
178 struct padata_instance *pinst = ps->pinst;
179 int i, cpu, cpu_index, err;
180 struct parallel_data *pd;
181 struct padata_work *pw;
182
183 rcu_read_lock_bh();
184
185 pd = rcu_dereference_bh(ps->pd);
186
187 err = -EINVAL;
188 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
189 goto out;
190
191 if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
192 if (cpumask_empty(pd->cpumask.cbcpu))
193 goto out;
194
195 /* Select an alternate fallback CPU and notify the caller. */
196 cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
197
198 cpu = cpumask_first(pd->cpumask.cbcpu);
199 for (i = 0; i < cpu_index; i++)
200 cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
201
202 *cb_cpu = cpu;
203 }
204
205 err = -EBUSY;
206 if ((pinst->flags & PADATA_RESET))
207 goto out;
208
209 refcount_inc(&pd->refcnt);
210 padata->pd = pd;
211 padata->cb_cpu = *cb_cpu;
212
213 spin_lock(&padata_works_lock);
214 padata->seq_nr = ++pd->seq_nr;
215 pw = padata_work_alloc();
216 spin_unlock(&padata_works_lock);
217
218 if (!pw) {
219 /* Maximum works limit exceeded, run in the current task. */
220 padata->parallel(padata);
221 }
222
223 rcu_read_unlock_bh();
224
225 if (pw) {
226 padata_work_init(pw, padata_parallel_worker, padata, 0);
227 queue_work(pinst->parallel_wq, &pw->pw_work);
228 }
229
230 return 0;
231out:
232 rcu_read_unlock_bh();
233
234 return err;
235}
236EXPORT_SYMBOL(padata_do_parallel);
237
238/*
239 * padata_find_next - Find the next object that needs serialization.
240 *
241 * Return:
242 * * A pointer to the control struct of the next object that needs
243 * serialization, if present in one of the percpu reorder queues.
244 * * NULL, if the next object that needs serialization will
245 * be parallel processed by another cpu and is not yet present in
246 * the cpu's reorder queue.
247 */
248static struct padata_priv *padata_find_next(struct parallel_data *pd,
249 bool remove_object)
250{
251 struct padata_priv *padata;
252 struct padata_list *reorder;
253 int cpu = pd->cpu;
254
255 reorder = per_cpu_ptr(pd->reorder_list, cpu);
256
257 spin_lock(&reorder->lock);
258 if (list_empty(&reorder->list)) {
259 spin_unlock(&reorder->lock);
260 return NULL;
261 }
262
263 padata = list_entry(reorder->list.next, struct padata_priv, list);
264
265 /*
266 * Checks the rare case where two or more parallel jobs have hashed to
267 * the same CPU and one of the later ones finishes first.
268 */
269 if (padata->seq_nr != pd->processed) {
270 spin_unlock(&reorder->lock);
271 return NULL;
272 }
273
274 if (remove_object) {
275 list_del_init(&padata->list);
276 ++pd->processed;
277 pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
278 }
279
280 spin_unlock(&reorder->lock);
281 return padata;
282}
283
284static void padata_reorder(struct parallel_data *pd)
285{
286 struct padata_instance *pinst = pd->ps->pinst;
287 int cb_cpu;
288 struct padata_priv *padata;
289 struct padata_serial_queue *squeue;
290 struct padata_list *reorder;
291
292 /*
293 * We need to ensure that only one cpu can work on dequeueing of
294 * the reorder queue the time. Calculating in which percpu reorder
295 * queue the next object will arrive takes some time. A spinlock
296 * would be highly contended. Also it is not clear in which order
297 * the objects arrive to the reorder queues. So a cpu could wait to
298 * get the lock just to notice that there is nothing to do at the
299 * moment. Therefore we use a trylock and let the holder of the lock
300 * care for all the objects enqueued during the holdtime of the lock.
301 */
302 if (!spin_trylock_bh(&pd->lock))
303 return;
304
305 while (1) {
306 padata = padata_find_next(pd, true);
307
308 /*
309 * If the next object that needs serialization is parallel
310 * processed by another cpu and is still on it's way to the
311 * cpu's reorder queue, nothing to do for now.
312 */
313 if (!padata)
314 break;
315
316 cb_cpu = padata->cb_cpu;
317 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
318
319 spin_lock(&squeue->serial.lock);
320 list_add_tail(&padata->list, &squeue->serial.list);
321 spin_unlock(&squeue->serial.lock);
322
323 queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
324 }
325
326 spin_unlock_bh(&pd->lock);
327
328 /*
329 * The next object that needs serialization might have arrived to
330 * the reorder queues in the meantime.
331 *
332 * Ensure reorder queue is read after pd->lock is dropped so we see
333 * new objects from another task in padata_do_serial. Pairs with
334 * smp_mb in padata_do_serial.
335 */
336 smp_mb();
337
338 reorder = per_cpu_ptr(pd->reorder_list, pd->cpu);
339 if (!list_empty(&reorder->list) && padata_find_next(pd, false))
340 queue_work(pinst->serial_wq, &pd->reorder_work);
341}
342
343static void invoke_padata_reorder(struct work_struct *work)
344{
345 struct parallel_data *pd;
346
347 local_bh_disable();
348 pd = container_of(work, struct parallel_data, reorder_work);
349 padata_reorder(pd);
350 local_bh_enable();
351}
352
353static void padata_serial_worker(struct work_struct *serial_work)
354{
355 struct padata_serial_queue *squeue;
356 struct parallel_data *pd;
357 LIST_HEAD(local_list);
358 int cnt;
359
360 local_bh_disable();
361 squeue = container_of(serial_work, struct padata_serial_queue, work);
362 pd = squeue->pd;
363
364 spin_lock(&squeue->serial.lock);
365 list_replace_init(&squeue->serial.list, &local_list);
366 spin_unlock(&squeue->serial.lock);
367
368 cnt = 0;
369
370 while (!list_empty(&local_list)) {
371 struct padata_priv *padata;
372
373 padata = list_entry(local_list.next,
374 struct padata_priv, list);
375
376 list_del_init(&padata->list);
377
378 padata->serial(padata);
379 cnt++;
380 }
381 local_bh_enable();
382
383 if (refcount_sub_and_test(cnt, &pd->refcnt))
384 padata_free_pd(pd);
385}
386
387/**
388 * padata_do_serial - padata serialization function
389 *
390 * @padata: object to be serialized.
391 *
392 * padata_do_serial must be called for every parallelized object.
393 * The serialization callback function will run with BHs off.
394 */
395void padata_do_serial(struct padata_priv *padata)
396{
397 struct parallel_data *pd = padata->pd;
398 int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr);
399 struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu);
400 struct padata_priv *cur;
401 struct list_head *pos;
402
403 spin_lock(&reorder->lock);
404 /* Sort in ascending order of sequence number. */
405 list_for_each_prev(pos, &reorder->list) {
406 cur = list_entry(pos, struct padata_priv, list);
407 /* Compare by difference to consider integer wrap around */
408 if ((signed int)(cur->seq_nr - padata->seq_nr) < 0)
409 break;
410 }
411 list_add(&padata->list, pos);
412 spin_unlock(&reorder->lock);
413
414 /*
415 * Ensure the addition to the reorder list is ordered correctly
416 * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
417 * in padata_reorder.
418 */
419 smp_mb();
420
421 padata_reorder(pd);
422}
423EXPORT_SYMBOL(padata_do_serial);
424
425static int padata_setup_cpumasks(struct padata_instance *pinst)
426{
427 struct workqueue_attrs *attrs;
428 int err;
429
430 attrs = alloc_workqueue_attrs();
431 if (!attrs)
432 return -ENOMEM;
433
434 /* Restrict parallel_wq workers to pd->cpumask.pcpu. */
435 cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu);
436 err = apply_workqueue_attrs(pinst->parallel_wq, attrs);
437 free_workqueue_attrs(attrs);
438
439 return err;
440}
441
442static void __init padata_mt_helper(struct work_struct *w)
443{
444 struct padata_work *pw = container_of(w, struct padata_work, pw_work);
445 struct padata_mt_job_state *ps = pw->pw_data;
446 struct padata_mt_job *job = ps->job;
447 bool done;
448
449 spin_lock(&ps->lock);
450
451 while (job->size > 0) {
452 unsigned long start, size, end;
453
454 start = job->start;
455 /* So end is chunk size aligned if enough work remains. */
456 size = roundup(start + 1, ps->chunk_size) - start;
457 size = min(size, job->size);
458 end = start + size;
459
460 job->start = end;
461 job->size -= size;
462
463 spin_unlock(&ps->lock);
464 job->thread_fn(start, end, job->fn_arg);
465 spin_lock(&ps->lock);
466 }
467
468 ++ps->nworks_fini;
469 done = (ps->nworks_fini == ps->nworks);
470 spin_unlock(&ps->lock);
471
472 if (done)
473 complete(&ps->completion);
474}
475
476/**
477 * padata_do_multithreaded - run a multithreaded job
478 * @job: Description of the job.
479 *
480 * See the definition of struct padata_mt_job for more details.
481 */
482void __init padata_do_multithreaded(struct padata_mt_job *job)
483{
484 /* In case threads finish at different times. */
485 static const unsigned long load_balance_factor = 4;
486 struct padata_work my_work, *pw;
487 struct padata_mt_job_state ps;
488 LIST_HEAD(works);
489 int nworks, nid;
490 static atomic_t last_used_nid __initdata;
491
492 if (job->size == 0)
493 return;
494
495 /* Ensure at least one thread when size < min_chunk. */
496 nworks = max(job->size / max(job->min_chunk, job->align), 1ul);
497 nworks = min(nworks, job->max_threads);
498
499 if (nworks == 1) {
500 /* Single thread, no coordination needed, cut to the chase. */
501 job->thread_fn(job->start, job->start + job->size, job->fn_arg);
502 return;
503 }
504
505 spin_lock_init(&ps.lock);
506 init_completion(&ps.completion);
507 ps.job = job;
508 ps.nworks = padata_work_alloc_mt(nworks, &ps, &works);
509 ps.nworks_fini = 0;
510
511 /*
512 * Chunk size is the amount of work a helper does per call to the
513 * thread function. Load balance large jobs between threads by
514 * increasing the number of chunks, guarantee at least the minimum
515 * chunk size from the caller, and honor the caller's alignment.
516 * Ensure chunk_size is at least 1 to prevent divide-by-0
517 * panic in padata_mt_helper().
518 */
519 ps.chunk_size = job->size / (ps.nworks * load_balance_factor);
520 ps.chunk_size = max(ps.chunk_size, job->min_chunk);
521 ps.chunk_size = max(ps.chunk_size, 1ul);
522 ps.chunk_size = roundup(ps.chunk_size, job->align);
523
524 list_for_each_entry(pw, &works, pw_list)
525 if (job->numa_aware) {
526 int old_node = atomic_read(&last_used_nid);
527
528 do {
529 nid = next_node_in(old_node, node_states[N_CPU]);
530 } while (!atomic_try_cmpxchg(&last_used_nid, &old_node, nid));
531 queue_work_node(nid, system_unbound_wq, &pw->pw_work);
532 } else {
533 queue_work(system_unbound_wq, &pw->pw_work);
534 }
535
536 /* Use the current thread, which saves starting a workqueue worker. */
537 padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK);
538 padata_mt_helper(&my_work.pw_work);
539
540 /* Wait for all the helpers to finish. */
541 wait_for_completion(&ps.completion);
542
543 destroy_work_on_stack(&my_work.pw_work);
544 padata_works_free(&works);
545}
546
547static void __padata_list_init(struct padata_list *pd_list)
548{
549 INIT_LIST_HEAD(&pd_list->list);
550 spin_lock_init(&pd_list->lock);
551}
552
553/* Initialize all percpu queues used by serial workers */
554static void padata_init_squeues(struct parallel_data *pd)
555{
556 int cpu;
557 struct padata_serial_queue *squeue;
558
559 for_each_cpu(cpu, pd->cpumask.cbcpu) {
560 squeue = per_cpu_ptr(pd->squeue, cpu);
561 squeue->pd = pd;
562 __padata_list_init(&squeue->serial);
563 INIT_WORK(&squeue->work, padata_serial_worker);
564 }
565}
566
567/* Initialize per-CPU reorder lists */
568static void padata_init_reorder_list(struct parallel_data *pd)
569{
570 int cpu;
571 struct padata_list *list;
572
573 for_each_cpu(cpu, pd->cpumask.pcpu) {
574 list = per_cpu_ptr(pd->reorder_list, cpu);
575 __padata_list_init(list);
576 }
577}
578
579/* Allocate and initialize the internal cpumask dependend resources. */
580static struct parallel_data *padata_alloc_pd(struct padata_shell *ps)
581{
582 struct padata_instance *pinst = ps->pinst;
583 struct parallel_data *pd;
584
585 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
586 if (!pd)
587 goto err;
588
589 pd->reorder_list = alloc_percpu(struct padata_list);
590 if (!pd->reorder_list)
591 goto err_free_pd;
592
593 pd->squeue = alloc_percpu(struct padata_serial_queue);
594 if (!pd->squeue)
595 goto err_free_reorder_list;
596
597 pd->ps = ps;
598
599 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
600 goto err_free_squeue;
601 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
602 goto err_free_pcpu;
603
604 cpumask_and(pd->cpumask.pcpu, pinst->cpumask.pcpu, cpu_online_mask);
605 cpumask_and(pd->cpumask.cbcpu, pinst->cpumask.cbcpu, cpu_online_mask);
606
607 padata_init_reorder_list(pd);
608 padata_init_squeues(pd);
609 pd->seq_nr = -1;
610 refcount_set(&pd->refcnt, 1);
611 spin_lock_init(&pd->lock);
612 pd->cpu = cpumask_first(pd->cpumask.pcpu);
613 INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
614
615 return pd;
616
617err_free_pcpu:
618 free_cpumask_var(pd->cpumask.pcpu);
619err_free_squeue:
620 free_percpu(pd->squeue);
621err_free_reorder_list:
622 free_percpu(pd->reorder_list);
623err_free_pd:
624 kfree(pd);
625err:
626 return NULL;
627}
628
629static void padata_free_pd(struct parallel_data *pd)
630{
631 free_cpumask_var(pd->cpumask.pcpu);
632 free_cpumask_var(pd->cpumask.cbcpu);
633 free_percpu(pd->reorder_list);
634 free_percpu(pd->squeue);
635 kfree(pd);
636}
637
638static void __padata_start(struct padata_instance *pinst)
639{
640 pinst->flags |= PADATA_INIT;
641}
642
643static void __padata_stop(struct padata_instance *pinst)
644{
645 if (!(pinst->flags & PADATA_INIT))
646 return;
647
648 pinst->flags &= ~PADATA_INIT;
649
650 synchronize_rcu();
651}
652
653/* Replace the internal control structure with a new one. */
654static int padata_replace_one(struct padata_shell *ps)
655{
656 struct parallel_data *pd_new;
657
658 pd_new = padata_alloc_pd(ps);
659 if (!pd_new)
660 return -ENOMEM;
661
662 ps->opd = rcu_dereference_protected(ps->pd, 1);
663 rcu_assign_pointer(ps->pd, pd_new);
664
665 return 0;
666}
667
668static int padata_replace(struct padata_instance *pinst)
669{
670 struct padata_shell *ps;
671 int err = 0;
672
673 pinst->flags |= PADATA_RESET;
674
675 list_for_each_entry(ps, &pinst->pslist, list) {
676 err = padata_replace_one(ps);
677 if (err)
678 break;
679 }
680
681 synchronize_rcu();
682
683 list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
684 if (refcount_dec_and_test(&ps->opd->refcnt))
685 padata_free_pd(ps->opd);
686
687 pinst->flags &= ~PADATA_RESET;
688
689 return err;
690}
691
692/* If cpumask contains no active cpu, we mark the instance as invalid. */
693static bool padata_validate_cpumask(struct padata_instance *pinst,
694 const struct cpumask *cpumask)
695{
696 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
697 pinst->flags |= PADATA_INVALID;
698 return false;
699 }
700
701 pinst->flags &= ~PADATA_INVALID;
702 return true;
703}
704
705static int __padata_set_cpumasks(struct padata_instance *pinst,
706 cpumask_var_t pcpumask,
707 cpumask_var_t cbcpumask)
708{
709 int valid;
710 int err;
711
712 valid = padata_validate_cpumask(pinst, pcpumask);
713 if (!valid) {
714 __padata_stop(pinst);
715 goto out_replace;
716 }
717
718 valid = padata_validate_cpumask(pinst, cbcpumask);
719 if (!valid)
720 __padata_stop(pinst);
721
722out_replace:
723 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
724 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
725
726 err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst);
727
728 if (valid)
729 __padata_start(pinst);
730
731 return err;
732}
733
734/**
735 * padata_set_cpumask - Sets specified by @cpumask_type cpumask to the value
736 * equivalent to @cpumask.
737 * @pinst: padata instance
738 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
739 * to parallel and serial cpumasks respectively.
740 * @cpumask: the cpumask to use
741 *
742 * Return: 0 on success or negative error code
743 */
744int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
745 cpumask_var_t cpumask)
746{
747 struct cpumask *serial_mask, *parallel_mask;
748 int err = -EINVAL;
749
750 cpus_read_lock();
751 mutex_lock(&pinst->lock);
752
753 switch (cpumask_type) {
754 case PADATA_CPU_PARALLEL:
755 serial_mask = pinst->cpumask.cbcpu;
756 parallel_mask = cpumask;
757 break;
758 case PADATA_CPU_SERIAL:
759 parallel_mask = pinst->cpumask.pcpu;
760 serial_mask = cpumask;
761 break;
762 default:
763 goto out;
764 }
765
766 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
767
768out:
769 mutex_unlock(&pinst->lock);
770 cpus_read_unlock();
771
772 return err;
773}
774EXPORT_SYMBOL(padata_set_cpumask);
775
776#ifdef CONFIG_HOTPLUG_CPU
777
778static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
779{
780 int err = 0;
781
782 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
783 err = padata_replace(pinst);
784
785 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
786 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
787 __padata_start(pinst);
788 }
789
790 return err;
791}
792
793static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
794{
795 int err = 0;
796
797 if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
798 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
799 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
800 __padata_stop(pinst);
801
802 err = padata_replace(pinst);
803 }
804
805 return err;
806}
807
808static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
809{
810 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
811 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
812}
813
814static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
815{
816 struct padata_instance *pinst;
817 int ret;
818
819 pinst = hlist_entry_safe(node, struct padata_instance, cpu_online_node);
820 if (!pinst_has_cpu(pinst, cpu))
821 return 0;
822
823 mutex_lock(&pinst->lock);
824 ret = __padata_add_cpu(pinst, cpu);
825 mutex_unlock(&pinst->lock);
826 return ret;
827}
828
829static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node)
830{
831 struct padata_instance *pinst;
832 int ret;
833
834 pinst = hlist_entry_safe(node, struct padata_instance, cpu_dead_node);
835 if (!pinst_has_cpu(pinst, cpu))
836 return 0;
837
838 mutex_lock(&pinst->lock);
839 ret = __padata_remove_cpu(pinst, cpu);
840 mutex_unlock(&pinst->lock);
841 return ret;
842}
843
844static enum cpuhp_state hp_online;
845#endif
846
847static void __padata_free(struct padata_instance *pinst)
848{
849#ifdef CONFIG_HOTPLUG_CPU
850 cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD,
851 &pinst->cpu_dead_node);
852 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->cpu_online_node);
853#endif
854
855 WARN_ON(!list_empty(&pinst->pslist));
856
857 free_cpumask_var(pinst->cpumask.pcpu);
858 free_cpumask_var(pinst->cpumask.cbcpu);
859 destroy_workqueue(pinst->serial_wq);
860 destroy_workqueue(pinst->parallel_wq);
861 kfree(pinst);
862}
863
864#define kobj2pinst(_kobj) \
865 container_of(_kobj, struct padata_instance, kobj)
866#define attr2pentry(_attr) \
867 container_of(_attr, struct padata_sysfs_entry, attr)
868
869static void padata_sysfs_release(struct kobject *kobj)
870{
871 struct padata_instance *pinst = kobj2pinst(kobj);
872 __padata_free(pinst);
873}
874
875struct padata_sysfs_entry {
876 struct attribute attr;
877 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
878 ssize_t (*store)(struct padata_instance *, struct attribute *,
879 const char *, size_t);
880};
881
882static ssize_t show_cpumask(struct padata_instance *pinst,
883 struct attribute *attr, char *buf)
884{
885 struct cpumask *cpumask;
886 ssize_t len;
887
888 mutex_lock(&pinst->lock);
889 if (!strcmp(attr->name, "serial_cpumask"))
890 cpumask = pinst->cpumask.cbcpu;
891 else
892 cpumask = pinst->cpumask.pcpu;
893
894 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
895 nr_cpu_ids, cpumask_bits(cpumask));
896 mutex_unlock(&pinst->lock);
897 return len < PAGE_SIZE ? len : -EINVAL;
898}
899
900static ssize_t store_cpumask(struct padata_instance *pinst,
901 struct attribute *attr,
902 const char *buf, size_t count)
903{
904 cpumask_var_t new_cpumask;
905 ssize_t ret;
906 int mask_type;
907
908 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
909 return -ENOMEM;
910
911 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
912 nr_cpumask_bits);
913 if (ret < 0)
914 goto out;
915
916 mask_type = !strcmp(attr->name, "serial_cpumask") ?
917 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
918 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
919 if (!ret)
920 ret = count;
921
922out:
923 free_cpumask_var(new_cpumask);
924 return ret;
925}
926
927#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
928 static struct padata_sysfs_entry _name##_attr = \
929 __ATTR(_name, 0644, _show_name, _store_name)
930#define PADATA_ATTR_RO(_name, _show_name) \
931 static struct padata_sysfs_entry _name##_attr = \
932 __ATTR(_name, 0400, _show_name, NULL)
933
934PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
935PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
936
937/*
938 * Padata sysfs provides the following objects:
939 * serial_cpumask [RW] - cpumask for serial workers
940 * parallel_cpumask [RW] - cpumask for parallel workers
941 */
942static struct attribute *padata_default_attrs[] = {
943 &serial_cpumask_attr.attr,
944 &parallel_cpumask_attr.attr,
945 NULL,
946};
947ATTRIBUTE_GROUPS(padata_default);
948
949static ssize_t padata_sysfs_show(struct kobject *kobj,
950 struct attribute *attr, char *buf)
951{
952 struct padata_instance *pinst;
953 struct padata_sysfs_entry *pentry;
954 ssize_t ret = -EIO;
955
956 pinst = kobj2pinst(kobj);
957 pentry = attr2pentry(attr);
958 if (pentry->show)
959 ret = pentry->show(pinst, attr, buf);
960
961 return ret;
962}
963
964static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
965 const char *buf, size_t count)
966{
967 struct padata_instance *pinst;
968 struct padata_sysfs_entry *pentry;
969 ssize_t ret = -EIO;
970
971 pinst = kobj2pinst(kobj);
972 pentry = attr2pentry(attr);
973 if (pentry->show)
974 ret = pentry->store(pinst, attr, buf, count);
975
976 return ret;
977}
978
979static const struct sysfs_ops padata_sysfs_ops = {
980 .show = padata_sysfs_show,
981 .store = padata_sysfs_store,
982};
983
984static const struct kobj_type padata_attr_type = {
985 .sysfs_ops = &padata_sysfs_ops,
986 .default_groups = padata_default_groups,
987 .release = padata_sysfs_release,
988};
989
990/**
991 * padata_alloc - allocate and initialize a padata instance
992 * @name: used to identify the instance
993 *
994 * Return: new instance on success, NULL on error
995 */
996struct padata_instance *padata_alloc(const char *name)
997{
998 struct padata_instance *pinst;
999
1000 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1001 if (!pinst)
1002 goto err;
1003
1004 pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
1005 name);
1006 if (!pinst->parallel_wq)
1007 goto err_free_inst;
1008
1009 cpus_read_lock();
1010
1011 pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
1012 WQ_CPU_INTENSIVE, 1, name);
1013 if (!pinst->serial_wq)
1014 goto err_put_cpus;
1015
1016 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1017 goto err_free_serial_wq;
1018 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1019 free_cpumask_var(pinst->cpumask.pcpu);
1020 goto err_free_serial_wq;
1021 }
1022
1023 INIT_LIST_HEAD(&pinst->pslist);
1024
1025 cpumask_copy(pinst->cpumask.pcpu, cpu_possible_mask);
1026 cpumask_copy(pinst->cpumask.cbcpu, cpu_possible_mask);
1027
1028 if (padata_setup_cpumasks(pinst))
1029 goto err_free_masks;
1030
1031 __padata_start(pinst);
1032
1033 kobject_init(&pinst->kobj, &padata_attr_type);
1034 mutex_init(&pinst->lock);
1035
1036#ifdef CONFIG_HOTPLUG_CPU
1037 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online,
1038 &pinst->cpu_online_node);
1039 cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
1040 &pinst->cpu_dead_node);
1041#endif
1042
1043 cpus_read_unlock();
1044
1045 return pinst;
1046
1047err_free_masks:
1048 free_cpumask_var(pinst->cpumask.pcpu);
1049 free_cpumask_var(pinst->cpumask.cbcpu);
1050err_free_serial_wq:
1051 destroy_workqueue(pinst->serial_wq);
1052err_put_cpus:
1053 cpus_read_unlock();
1054 destroy_workqueue(pinst->parallel_wq);
1055err_free_inst:
1056 kfree(pinst);
1057err:
1058 return NULL;
1059}
1060EXPORT_SYMBOL(padata_alloc);
1061
1062/**
1063 * padata_free - free a padata instance
1064 *
1065 * @pinst: padata instance to free
1066 */
1067void padata_free(struct padata_instance *pinst)
1068{
1069 kobject_put(&pinst->kobj);
1070}
1071EXPORT_SYMBOL(padata_free);
1072
1073/**
1074 * padata_alloc_shell - Allocate and initialize padata shell.
1075 *
1076 * @pinst: Parent padata_instance object.
1077 *
1078 * Return: new shell on success, NULL on error
1079 */
1080struct padata_shell *padata_alloc_shell(struct padata_instance *pinst)
1081{
1082 struct parallel_data *pd;
1083 struct padata_shell *ps;
1084
1085 ps = kzalloc(sizeof(*ps), GFP_KERNEL);
1086 if (!ps)
1087 goto out;
1088
1089 ps->pinst = pinst;
1090
1091 cpus_read_lock();
1092 pd = padata_alloc_pd(ps);
1093 cpus_read_unlock();
1094
1095 if (!pd)
1096 goto out_free_ps;
1097
1098 mutex_lock(&pinst->lock);
1099 RCU_INIT_POINTER(ps->pd, pd);
1100 list_add(&ps->list, &pinst->pslist);
1101 mutex_unlock(&pinst->lock);
1102
1103 return ps;
1104
1105out_free_ps:
1106 kfree(ps);
1107out:
1108 return NULL;
1109}
1110EXPORT_SYMBOL(padata_alloc_shell);
1111
1112/**
1113 * padata_free_shell - free a padata shell
1114 *
1115 * @ps: padata shell to free
1116 */
1117void padata_free_shell(struct padata_shell *ps)
1118{
1119 struct parallel_data *pd;
1120
1121 if (!ps)
1122 return;
1123
1124 mutex_lock(&ps->pinst->lock);
1125 list_del(&ps->list);
1126 pd = rcu_dereference_protected(ps->pd, 1);
1127 if (refcount_dec_and_test(&pd->refcnt))
1128 padata_free_pd(pd);
1129 mutex_unlock(&ps->pinst->lock);
1130
1131 kfree(ps);
1132}
1133EXPORT_SYMBOL(padata_free_shell);
1134
1135void __init padata_init(void)
1136{
1137 unsigned int i, possible_cpus;
1138#ifdef CONFIG_HOTPLUG_CPU
1139 int ret;
1140
1141 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1142 padata_cpu_online, NULL);
1143 if (ret < 0)
1144 goto err;
1145 hp_online = ret;
1146
1147 ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead",
1148 NULL, padata_cpu_dead);
1149 if (ret < 0)
1150 goto remove_online_state;
1151#endif
1152
1153 possible_cpus = num_possible_cpus();
1154 padata_works = kmalloc_array(possible_cpus, sizeof(struct padata_work),
1155 GFP_KERNEL);
1156 if (!padata_works)
1157 goto remove_dead_state;
1158
1159 for (i = 0; i < possible_cpus; ++i)
1160 list_add(&padata_works[i].pw_list, &padata_free_works);
1161
1162 return;
1163
1164remove_dead_state:
1165#ifdef CONFIG_HOTPLUG_CPU
1166 cpuhp_remove_multi_state(CPUHP_PADATA_DEAD);
1167remove_online_state:
1168 cpuhp_remove_multi_state(hp_online);
1169err:
1170#endif
1171 pr_warn("padata: initialization failed\n");
1172}