Merge tag 'locks-v3.16-2' of git://git.samba.org/jlayton/linux
[linux/fpc-iii.git] / kernel / padata.c
blob161402f0b517c9f483f166585bd61d61bac2e3f3
1 /*
2 * padata.c - generic interface to process data streams in parallel
4 * See Documentation/padata.txt for an api documentation.
6 * Copyright (C) 2008, 2009 secunet Security Networks AG
7 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms and conditions of the GNU General Public License,
11 * version 2, as published by the Free Software Foundation.
13 * This program is distributed in the hope it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
16 * more details.
18 * You should have received a copy of the GNU General Public License along with
19 * this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
23 #include <linux/export.h>
24 #include <linux/cpumask.h>
25 #include <linux/err.h>
26 #include <linux/cpu.h>
27 #include <linux/padata.h>
28 #include <linux/mutex.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31 #include <linux/sysfs.h>
32 #include <linux/rcupdate.h>
34 #define MAX_OBJ_NUM 1000
36 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
38 int cpu, target_cpu;
40 target_cpu = cpumask_first(pd->cpumask.pcpu);
41 for (cpu = 0; cpu < cpu_index; cpu++)
42 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
44 return target_cpu;
47 static int padata_cpu_hash(struct parallel_data *pd)
49 unsigned int seq_nr;
50 int cpu_index;
53 * Hash the sequence numbers to the cpus by taking
54 * seq_nr mod. number of cpus in use.
57 seq_nr = atomic_inc_return(&pd->seq_nr);
58 cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
60 return padata_index_to_cpu(pd, cpu_index);
63 static void padata_parallel_worker(struct work_struct *parallel_work)
65 struct padata_parallel_queue *pqueue;
66 struct parallel_data *pd;
67 struct padata_instance *pinst;
68 LIST_HEAD(local_list);
70 local_bh_disable();
71 pqueue = container_of(parallel_work,
72 struct padata_parallel_queue, work);
73 pd = pqueue->pd;
74 pinst = pd->pinst;
76 spin_lock(&pqueue->parallel.lock);
77 list_replace_init(&pqueue->parallel.list, &local_list);
78 spin_unlock(&pqueue->parallel.lock);
80 while (!list_empty(&local_list)) {
81 struct padata_priv *padata;
83 padata = list_entry(local_list.next,
84 struct padata_priv, list);
86 list_del_init(&padata->list);
88 padata->parallel(padata);
91 local_bh_enable();
94 /**
95 * padata_do_parallel - padata parallelization function
97 * @pinst: padata instance
98 * @padata: object to be parallelized
99 * @cb_cpu: cpu the serialization callback function will run on,
100 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
102 * The parallelization callback function will run with BHs off.
103 * Note: Every object which is parallelized by padata_do_parallel
104 * must be seen by padata_do_serial.
106 int padata_do_parallel(struct padata_instance *pinst,
107 struct padata_priv *padata, int cb_cpu)
109 int target_cpu, err;
110 struct padata_parallel_queue *queue;
111 struct parallel_data *pd;
113 rcu_read_lock_bh();
115 pd = rcu_dereference_bh(pinst->pd);
117 err = -EINVAL;
118 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
119 goto out;
121 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
122 goto out;
124 err = -EBUSY;
125 if ((pinst->flags & PADATA_RESET))
126 goto out;
128 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
129 goto out;
131 err = 0;
132 atomic_inc(&pd->refcnt);
133 padata->pd = pd;
134 padata->cb_cpu = cb_cpu;
136 target_cpu = padata_cpu_hash(pd);
137 queue = per_cpu_ptr(pd->pqueue, target_cpu);
139 spin_lock(&queue->parallel.lock);
140 list_add_tail(&padata->list, &queue->parallel.list);
141 spin_unlock(&queue->parallel.lock);
143 queue_work_on(target_cpu, pinst->wq, &queue->work);
145 out:
146 rcu_read_unlock_bh();
148 return err;
150 EXPORT_SYMBOL(padata_do_parallel);
153 * padata_get_next - Get the next object that needs serialization.
155 * Return values are:
157 * A pointer to the control struct of the next object that needs
158 * serialization, if present in one of the percpu reorder queues.
160 * NULL, if all percpu reorder queues are empty.
162 * -EINPROGRESS, if the next object that needs serialization will
163 * be parallel processed by another cpu and is not yet present in
164 * the cpu's reorder queue.
166 * -ENODATA, if this cpu has to do the parallel processing for
167 * the next object.
169 static struct padata_priv *padata_get_next(struct parallel_data *pd)
171 int cpu, num_cpus;
172 unsigned int next_nr, next_index;
173 struct padata_parallel_queue *next_queue;
174 struct padata_priv *padata;
175 struct padata_list *reorder;
177 num_cpus = cpumask_weight(pd->cpumask.pcpu);
180 * Calculate the percpu reorder queue and the sequence
181 * number of the next object.
183 next_nr = pd->processed;
184 next_index = next_nr % num_cpus;
185 cpu = padata_index_to_cpu(pd, next_index);
186 next_queue = per_cpu_ptr(pd->pqueue, cpu);
188 padata = NULL;
190 reorder = &next_queue->reorder;
192 if (!list_empty(&reorder->list)) {
193 padata = list_entry(reorder->list.next,
194 struct padata_priv, list);
196 spin_lock(&reorder->lock);
197 list_del_init(&padata->list);
198 atomic_dec(&pd->reorder_objects);
199 spin_unlock(&reorder->lock);
201 pd->processed++;
203 goto out;
206 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
207 padata = ERR_PTR(-ENODATA);
208 goto out;
211 padata = ERR_PTR(-EINPROGRESS);
212 out:
213 return padata;
216 static void padata_reorder(struct parallel_data *pd)
218 int cb_cpu;
219 struct padata_priv *padata;
220 struct padata_serial_queue *squeue;
221 struct padata_instance *pinst = pd->pinst;
224 * We need to ensure that only one cpu can work on dequeueing of
225 * the reorder queue the time. Calculating in which percpu reorder
226 * queue the next object will arrive takes some time. A spinlock
227 * would be highly contended. Also it is not clear in which order
228 * the objects arrive to the reorder queues. So a cpu could wait to
229 * get the lock just to notice that there is nothing to do at the
230 * moment. Therefore we use a trylock and let the holder of the lock
231 * care for all the objects enqueued during the holdtime of the lock.
233 if (!spin_trylock_bh(&pd->lock))
234 return;
236 while (1) {
237 padata = padata_get_next(pd);
240 * All reorder queues are empty, or the next object that needs
241 * serialization is parallel processed by another cpu and is
242 * still on it's way to the cpu's reorder queue, nothing to
243 * do for now.
245 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
246 break;
249 * This cpu has to do the parallel processing of the next
250 * object. It's waiting in the cpu's parallelization queue,
251 * so exit immediately.
253 if (PTR_ERR(padata) == -ENODATA) {
254 del_timer(&pd->timer);
255 spin_unlock_bh(&pd->lock);
256 return;
259 cb_cpu = padata->cb_cpu;
260 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
262 spin_lock(&squeue->serial.lock);
263 list_add_tail(&padata->list, &squeue->serial.list);
264 spin_unlock(&squeue->serial.lock);
266 queue_work_on(cb_cpu, pinst->wq, &squeue->work);
269 spin_unlock_bh(&pd->lock);
272 * The next object that needs serialization might have arrived to
273 * the reorder queues in the meantime, we will be called again
274 * from the timer function if no one else cares for it.
276 if (atomic_read(&pd->reorder_objects)
277 && !(pinst->flags & PADATA_RESET))
278 mod_timer(&pd->timer, jiffies + HZ);
279 else
280 del_timer(&pd->timer);
282 return;
285 static void padata_reorder_timer(unsigned long arg)
287 struct parallel_data *pd = (struct parallel_data *)arg;
289 padata_reorder(pd);
292 static void padata_serial_worker(struct work_struct *serial_work)
294 struct padata_serial_queue *squeue;
295 struct parallel_data *pd;
296 LIST_HEAD(local_list);
298 local_bh_disable();
299 squeue = container_of(serial_work, struct padata_serial_queue, work);
300 pd = squeue->pd;
302 spin_lock(&squeue->serial.lock);
303 list_replace_init(&squeue->serial.list, &local_list);
304 spin_unlock(&squeue->serial.lock);
306 while (!list_empty(&local_list)) {
307 struct padata_priv *padata;
309 padata = list_entry(local_list.next,
310 struct padata_priv, list);
312 list_del_init(&padata->list);
314 padata->serial(padata);
315 atomic_dec(&pd->refcnt);
317 local_bh_enable();
321 * padata_do_serial - padata serialization function
323 * @padata: object to be serialized.
325 * padata_do_serial must be called for every parallelized object.
326 * The serialization callback function will run with BHs off.
328 void padata_do_serial(struct padata_priv *padata)
330 int cpu;
331 struct padata_parallel_queue *pqueue;
332 struct parallel_data *pd;
334 pd = padata->pd;
336 cpu = get_cpu();
337 pqueue = per_cpu_ptr(pd->pqueue, cpu);
339 spin_lock(&pqueue->reorder.lock);
340 atomic_inc(&pd->reorder_objects);
341 list_add_tail(&padata->list, &pqueue->reorder.list);
342 spin_unlock(&pqueue->reorder.lock);
344 put_cpu();
346 padata_reorder(pd);
348 EXPORT_SYMBOL(padata_do_serial);
350 static int padata_setup_cpumasks(struct parallel_data *pd,
351 const struct cpumask *pcpumask,
352 const struct cpumask *cbcpumask)
354 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
355 return -ENOMEM;
357 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
358 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
359 free_cpumask_var(pd->cpumask.cbcpu);
360 return -ENOMEM;
363 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
364 return 0;
367 static void __padata_list_init(struct padata_list *pd_list)
369 INIT_LIST_HEAD(&pd_list->list);
370 spin_lock_init(&pd_list->lock);
373 /* Initialize all percpu queues used by serial workers */
374 static void padata_init_squeues(struct parallel_data *pd)
376 int cpu;
377 struct padata_serial_queue *squeue;
379 for_each_cpu(cpu, pd->cpumask.cbcpu) {
380 squeue = per_cpu_ptr(pd->squeue, cpu);
381 squeue->pd = pd;
382 __padata_list_init(&squeue->serial);
383 INIT_WORK(&squeue->work, padata_serial_worker);
387 /* Initialize all percpu queues used by parallel workers */
388 static void padata_init_pqueues(struct parallel_data *pd)
390 int cpu_index, cpu;
391 struct padata_parallel_queue *pqueue;
393 cpu_index = 0;
394 for_each_cpu(cpu, pd->cpumask.pcpu) {
395 pqueue = per_cpu_ptr(pd->pqueue, cpu);
396 pqueue->pd = pd;
397 pqueue->cpu_index = cpu_index;
398 cpu_index++;
400 __padata_list_init(&pqueue->reorder);
401 __padata_list_init(&pqueue->parallel);
402 INIT_WORK(&pqueue->work, padata_parallel_worker);
403 atomic_set(&pqueue->num_obj, 0);
407 /* Allocate and initialize the internal cpumask dependend resources. */
408 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
409 const struct cpumask *pcpumask,
410 const struct cpumask *cbcpumask)
412 struct parallel_data *pd;
414 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
415 if (!pd)
416 goto err;
418 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
419 if (!pd->pqueue)
420 goto err_free_pd;
422 pd->squeue = alloc_percpu(struct padata_serial_queue);
423 if (!pd->squeue)
424 goto err_free_pqueue;
425 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
426 goto err_free_squeue;
428 padata_init_pqueues(pd);
429 padata_init_squeues(pd);
430 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
431 atomic_set(&pd->seq_nr, -1);
432 atomic_set(&pd->reorder_objects, 0);
433 atomic_set(&pd->refcnt, 0);
434 pd->pinst = pinst;
435 spin_lock_init(&pd->lock);
437 return pd;
439 err_free_squeue:
440 free_percpu(pd->squeue);
441 err_free_pqueue:
442 free_percpu(pd->pqueue);
443 err_free_pd:
444 kfree(pd);
445 err:
446 return NULL;
449 static void padata_free_pd(struct parallel_data *pd)
451 free_cpumask_var(pd->cpumask.pcpu);
452 free_cpumask_var(pd->cpumask.cbcpu);
453 free_percpu(pd->pqueue);
454 free_percpu(pd->squeue);
455 kfree(pd);
458 /* Flush all objects out of the padata queues. */
459 static void padata_flush_queues(struct parallel_data *pd)
461 int cpu;
462 struct padata_parallel_queue *pqueue;
463 struct padata_serial_queue *squeue;
465 for_each_cpu(cpu, pd->cpumask.pcpu) {
466 pqueue = per_cpu_ptr(pd->pqueue, cpu);
467 flush_work(&pqueue->work);
470 del_timer_sync(&pd->timer);
472 if (atomic_read(&pd->reorder_objects))
473 padata_reorder(pd);
475 for_each_cpu(cpu, pd->cpumask.cbcpu) {
476 squeue = per_cpu_ptr(pd->squeue, cpu);
477 flush_work(&squeue->work);
480 BUG_ON(atomic_read(&pd->refcnt) != 0);
483 static void __padata_start(struct padata_instance *pinst)
485 pinst->flags |= PADATA_INIT;
488 static void __padata_stop(struct padata_instance *pinst)
490 if (!(pinst->flags & PADATA_INIT))
491 return;
493 pinst->flags &= ~PADATA_INIT;
495 synchronize_rcu();
497 get_online_cpus();
498 padata_flush_queues(pinst->pd);
499 put_online_cpus();
502 /* Replace the internal control structure with a new one. */
503 static void padata_replace(struct padata_instance *pinst,
504 struct parallel_data *pd_new)
506 struct parallel_data *pd_old = pinst->pd;
507 int notification_mask = 0;
509 pinst->flags |= PADATA_RESET;
511 rcu_assign_pointer(pinst->pd, pd_new);
513 synchronize_rcu();
515 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
516 notification_mask |= PADATA_CPU_PARALLEL;
517 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
518 notification_mask |= PADATA_CPU_SERIAL;
520 padata_flush_queues(pd_old);
521 padata_free_pd(pd_old);
523 if (notification_mask)
524 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
525 notification_mask,
526 &pd_new->cpumask);
528 pinst->flags &= ~PADATA_RESET;
532 * padata_register_cpumask_notifier - Registers a notifier that will be called
533 * if either pcpu or cbcpu or both cpumasks change.
535 * @pinst: A poineter to padata instance
536 * @nblock: A pointer to notifier block.
538 int padata_register_cpumask_notifier(struct padata_instance *pinst,
539 struct notifier_block *nblock)
541 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
542 nblock);
544 EXPORT_SYMBOL(padata_register_cpumask_notifier);
547 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
548 * registered earlier using padata_register_cpumask_notifier
550 * @pinst: A pointer to data instance.
551 * @nlock: A pointer to notifier block.
553 int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
554 struct notifier_block *nblock)
556 return blocking_notifier_chain_unregister(
557 &pinst->cpumask_change_notifier,
558 nblock);
560 EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
563 /* If cpumask contains no active cpu, we mark the instance as invalid. */
564 static bool padata_validate_cpumask(struct padata_instance *pinst,
565 const struct cpumask *cpumask)
567 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
568 pinst->flags |= PADATA_INVALID;
569 return false;
572 pinst->flags &= ~PADATA_INVALID;
573 return true;
576 static int __padata_set_cpumasks(struct padata_instance *pinst,
577 cpumask_var_t pcpumask,
578 cpumask_var_t cbcpumask)
580 int valid;
581 struct parallel_data *pd;
583 valid = padata_validate_cpumask(pinst, pcpumask);
584 if (!valid) {
585 __padata_stop(pinst);
586 goto out_replace;
589 valid = padata_validate_cpumask(pinst, cbcpumask);
590 if (!valid)
591 __padata_stop(pinst);
593 out_replace:
594 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
595 if (!pd)
596 return -ENOMEM;
598 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
599 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
601 padata_replace(pinst, pd);
603 if (valid)
604 __padata_start(pinst);
606 return 0;
610 * padata_set_cpumasks - Set both parallel and serial cpumasks. The first
611 * one is used by parallel workers and the second one
612 * by the wokers doing serialization.
614 * @pinst: padata instance
615 * @pcpumask: the cpumask to use for parallel workers
616 * @cbcpumask: the cpumsak to use for serial workers
618 int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
619 cpumask_var_t cbcpumask)
621 int err;
623 mutex_lock(&pinst->lock);
624 get_online_cpus();
626 err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
628 put_online_cpus();
629 mutex_unlock(&pinst->lock);
631 return err;
634 EXPORT_SYMBOL(padata_set_cpumasks);
637 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
638 * equivalent to @cpumask.
640 * @pinst: padata instance
641 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
642 * to parallel and serial cpumasks respectively.
643 * @cpumask: the cpumask to use
645 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
646 cpumask_var_t cpumask)
648 struct cpumask *serial_mask, *parallel_mask;
649 int err = -EINVAL;
651 mutex_lock(&pinst->lock);
652 get_online_cpus();
654 switch (cpumask_type) {
655 case PADATA_CPU_PARALLEL:
656 serial_mask = pinst->cpumask.cbcpu;
657 parallel_mask = cpumask;
658 break;
659 case PADATA_CPU_SERIAL:
660 parallel_mask = pinst->cpumask.pcpu;
661 serial_mask = cpumask;
662 break;
663 default:
664 goto out;
667 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
669 out:
670 put_online_cpus();
671 mutex_unlock(&pinst->lock);
673 return err;
675 EXPORT_SYMBOL(padata_set_cpumask);
677 static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
679 struct parallel_data *pd;
681 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
682 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
683 pinst->cpumask.cbcpu);
684 if (!pd)
685 return -ENOMEM;
687 padata_replace(pinst, pd);
689 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
690 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
691 __padata_start(pinst);
694 return 0;
698 * padata_add_cpu - add a cpu to one or both(parallel and serial)
699 * padata cpumasks.
701 * @pinst: padata instance
702 * @cpu: cpu to add
703 * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
704 * The @mask may be any combination of the following flags:
705 * PADATA_CPU_SERIAL - serial cpumask
706 * PADATA_CPU_PARALLEL - parallel cpumask
709 int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask)
711 int err;
713 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
714 return -EINVAL;
716 mutex_lock(&pinst->lock);
718 get_online_cpus();
719 if (mask & PADATA_CPU_SERIAL)
720 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu);
721 if (mask & PADATA_CPU_PARALLEL)
722 cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
724 err = __padata_add_cpu(pinst, cpu);
725 put_online_cpus();
727 mutex_unlock(&pinst->lock);
729 return err;
731 EXPORT_SYMBOL(padata_add_cpu);
733 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
735 struct parallel_data *pd = NULL;
737 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
739 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
740 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
741 __padata_stop(pinst);
743 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
744 pinst->cpumask.cbcpu);
745 if (!pd)
746 return -ENOMEM;
748 padata_replace(pinst, pd);
750 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
751 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
754 return 0;
758 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
759 * padata cpumasks.
761 * @pinst: padata instance
762 * @cpu: cpu to remove
763 * @mask: bitmask specifying from which cpumask @cpu should be removed
764 * The @mask may be any combination of the following flags:
765 * PADATA_CPU_SERIAL - serial cpumask
766 * PADATA_CPU_PARALLEL - parallel cpumask
768 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
770 int err;
772 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
773 return -EINVAL;
775 mutex_lock(&pinst->lock);
777 get_online_cpus();
778 if (mask & PADATA_CPU_SERIAL)
779 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
780 if (mask & PADATA_CPU_PARALLEL)
781 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
783 err = __padata_remove_cpu(pinst, cpu);
784 put_online_cpus();
786 mutex_unlock(&pinst->lock);
788 return err;
790 EXPORT_SYMBOL(padata_remove_cpu);
793 * padata_start - start the parallel processing
795 * @pinst: padata instance to start
797 int padata_start(struct padata_instance *pinst)
799 int err = 0;
801 mutex_lock(&pinst->lock);
803 if (pinst->flags & PADATA_INVALID)
804 err =-EINVAL;
806 __padata_start(pinst);
808 mutex_unlock(&pinst->lock);
810 return err;
812 EXPORT_SYMBOL(padata_start);
815 * padata_stop - stop the parallel processing
817 * @pinst: padata instance to stop
819 void padata_stop(struct padata_instance *pinst)
821 mutex_lock(&pinst->lock);
822 __padata_stop(pinst);
823 mutex_unlock(&pinst->lock);
825 EXPORT_SYMBOL(padata_stop);
827 #ifdef CONFIG_HOTPLUG_CPU
829 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
831 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
832 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
836 static int padata_cpu_callback(struct notifier_block *nfb,
837 unsigned long action, void *hcpu)
839 int err;
840 struct padata_instance *pinst;
841 int cpu = (unsigned long)hcpu;
843 pinst = container_of(nfb, struct padata_instance, cpu_notifier);
845 switch (action) {
846 case CPU_ONLINE:
847 case CPU_ONLINE_FROZEN:
848 case CPU_DOWN_FAILED:
849 case CPU_DOWN_FAILED_FROZEN:
850 if (!pinst_has_cpu(pinst, cpu))
851 break;
852 mutex_lock(&pinst->lock);
853 err = __padata_add_cpu(pinst, cpu);
854 mutex_unlock(&pinst->lock);
855 if (err)
856 return notifier_from_errno(err);
857 break;
859 case CPU_DOWN_PREPARE:
860 case CPU_DOWN_PREPARE_FROZEN:
861 case CPU_UP_CANCELED:
862 case CPU_UP_CANCELED_FROZEN:
863 if (!pinst_has_cpu(pinst, cpu))
864 break;
865 mutex_lock(&pinst->lock);
866 err = __padata_remove_cpu(pinst, cpu);
867 mutex_unlock(&pinst->lock);
868 if (err)
869 return notifier_from_errno(err);
870 break;
873 return NOTIFY_OK;
875 #endif
877 static void __padata_free(struct padata_instance *pinst)
879 #ifdef CONFIG_HOTPLUG_CPU
880 unregister_hotcpu_notifier(&pinst->cpu_notifier);
881 #endif
883 padata_stop(pinst);
884 padata_free_pd(pinst->pd);
885 free_cpumask_var(pinst->cpumask.pcpu);
886 free_cpumask_var(pinst->cpumask.cbcpu);
887 kfree(pinst);
890 #define kobj2pinst(_kobj) \
891 container_of(_kobj, struct padata_instance, kobj)
892 #define attr2pentry(_attr) \
893 container_of(_attr, struct padata_sysfs_entry, attr)
895 static void padata_sysfs_release(struct kobject *kobj)
897 struct padata_instance *pinst = kobj2pinst(kobj);
898 __padata_free(pinst);
901 struct padata_sysfs_entry {
902 struct attribute attr;
903 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
904 ssize_t (*store)(struct padata_instance *, struct attribute *,
905 const char *, size_t);
908 static ssize_t show_cpumask(struct padata_instance *pinst,
909 struct attribute *attr, char *buf)
911 struct cpumask *cpumask;
912 ssize_t len;
914 mutex_lock(&pinst->lock);
915 if (!strcmp(attr->name, "serial_cpumask"))
916 cpumask = pinst->cpumask.cbcpu;
917 else
918 cpumask = pinst->cpumask.pcpu;
920 len = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask),
921 nr_cpu_ids);
922 if (PAGE_SIZE - len < 2)
923 len = -EINVAL;
924 else
925 len += sprintf(buf + len, "\n");
927 mutex_unlock(&pinst->lock);
928 return len;
931 static ssize_t store_cpumask(struct padata_instance *pinst,
932 struct attribute *attr,
933 const char *buf, size_t count)
935 cpumask_var_t new_cpumask;
936 ssize_t ret;
937 int mask_type;
939 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
940 return -ENOMEM;
942 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
943 nr_cpumask_bits);
944 if (ret < 0)
945 goto out;
947 mask_type = !strcmp(attr->name, "serial_cpumask") ?
948 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
949 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
950 if (!ret)
951 ret = count;
953 out:
954 free_cpumask_var(new_cpumask);
955 return ret;
958 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \
959 static struct padata_sysfs_entry _name##_attr = \
960 __ATTR(_name, 0644, _show_name, _store_name)
961 #define PADATA_ATTR_RO(_name, _show_name) \
962 static struct padata_sysfs_entry _name##_attr = \
963 __ATTR(_name, 0400, _show_name, NULL)
965 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
966 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
969 * Padata sysfs provides the following objects:
970 * serial_cpumask [RW] - cpumask for serial workers
971 * parallel_cpumask [RW] - cpumask for parallel workers
973 static struct attribute *padata_default_attrs[] = {
974 &serial_cpumask_attr.attr,
975 &parallel_cpumask_attr.attr,
976 NULL,
979 static ssize_t padata_sysfs_show(struct kobject *kobj,
980 struct attribute *attr, char *buf)
982 struct padata_instance *pinst;
983 struct padata_sysfs_entry *pentry;
984 ssize_t ret = -EIO;
986 pinst = kobj2pinst(kobj);
987 pentry = attr2pentry(attr);
988 if (pentry->show)
989 ret = pentry->show(pinst, attr, buf);
991 return ret;
994 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
995 const char *buf, size_t count)
997 struct padata_instance *pinst;
998 struct padata_sysfs_entry *pentry;
999 ssize_t ret = -EIO;
1001 pinst = kobj2pinst(kobj);
1002 pentry = attr2pentry(attr);
1003 if (pentry->show)
1004 ret = pentry->store(pinst, attr, buf, count);
1006 return ret;
1009 static const struct sysfs_ops padata_sysfs_ops = {
1010 .show = padata_sysfs_show,
1011 .store = padata_sysfs_store,
1014 static struct kobj_type padata_attr_type = {
1015 .sysfs_ops = &padata_sysfs_ops,
1016 .default_attrs = padata_default_attrs,
1017 .release = padata_sysfs_release,
1021 * padata_alloc_possible - Allocate and initialize padata instance.
1022 * Use the cpu_possible_mask for serial and
1023 * parallel workers.
1025 * @wq: workqueue to use for the allocated padata instance
1027 struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1029 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1031 EXPORT_SYMBOL(padata_alloc_possible);
1034 * padata_alloc - allocate and initialize a padata instance and specify
1035 * cpumasks for serial and parallel workers.
1037 * @wq: workqueue to use for the allocated padata instance
1038 * @pcpumask: cpumask that will be used for padata parallelization
1039 * @cbcpumask: cpumask that will be used for padata serialization
1041 struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1042 const struct cpumask *pcpumask,
1043 const struct cpumask *cbcpumask)
1045 struct padata_instance *pinst;
1046 struct parallel_data *pd = NULL;
1048 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1049 if (!pinst)
1050 goto err;
1052 get_online_cpus();
1053 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1054 goto err_free_inst;
1055 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1056 free_cpumask_var(pinst->cpumask.pcpu);
1057 goto err_free_inst;
1059 if (!padata_validate_cpumask(pinst, pcpumask) ||
1060 !padata_validate_cpumask(pinst, cbcpumask))
1061 goto err_free_masks;
1063 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1064 if (!pd)
1065 goto err_free_masks;
1067 rcu_assign_pointer(pinst->pd, pd);
1069 pinst->wq = wq;
1071 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1072 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1074 pinst->flags = 0;
1076 put_online_cpus();
1078 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1079 kobject_init(&pinst->kobj, &padata_attr_type);
1080 mutex_init(&pinst->lock);
1082 #ifdef CONFIG_HOTPLUG_CPU
1083 pinst->cpu_notifier.notifier_call = padata_cpu_callback;
1084 pinst->cpu_notifier.priority = 0;
1085 register_hotcpu_notifier(&pinst->cpu_notifier);
1086 #endif
1088 return pinst;
1090 err_free_masks:
1091 free_cpumask_var(pinst->cpumask.pcpu);
1092 free_cpumask_var(pinst->cpumask.cbcpu);
1093 err_free_inst:
1094 kfree(pinst);
1095 put_online_cpus();
1096 err:
1097 return NULL;
1099 EXPORT_SYMBOL(padata_alloc);
1102 * padata_free - free a padata instance
1104 * @padata_inst: padata instance to free
1106 void padata_free(struct padata_instance *pinst)
1108 kobject_put(&pinst->kobj);
1110 EXPORT_SYMBOL(padata_free);