1 // SPDX-License-Identifier: GPL-2.0
3 * padata.c - generic interface to process data streams in parallel
5 * See Documentation/padata.txt for an api documentation.
7 * Copyright (C) 2008, 2009 secunet Security Networks AG
8 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms and conditions of the GNU General Public License,
12 * version 2, as published by the Free Software Foundation.
14 * This program is distributed in the hope it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
19 * You should have received a copy of the GNU General Public License along with
20 * this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
24 #include <linux/export.h>
25 #include <linux/cpumask.h>
26 #include <linux/err.h>
27 #include <linux/cpu.h>
28 #include <linux/padata.h>
29 #include <linux/mutex.h>
30 #include <linux/sched.h>
31 #include <linux/slab.h>
32 #include <linux/sysfs.h>
33 #include <linux/rcupdate.h>
34 #include <linux/module.h>
36 #define MAX_OBJ_NUM 1000
38 static void padata_free_pd(struct parallel_data *pd);
40 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
44 target_cpu = cpumask_first(pd->cpumask.pcpu);
45 for (cpu = 0; cpu < cpu_index; cpu++)
46 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
51 static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
54 * Hash the sequence numbers to the cpus by taking
55 * seq_nr mod. number of cpus in use.
57 int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
59 return padata_index_to_cpu(pd, cpu_index);
62 static void padata_parallel_worker(struct work_struct *parallel_work)
64 struct padata_parallel_queue *pqueue;
65 LIST_HEAD(local_list);
68 pqueue = container_of(parallel_work,
69 struct padata_parallel_queue, work);
71 spin_lock(&pqueue->parallel.lock);
72 list_replace_init(&pqueue->parallel.list, &local_list);
73 spin_unlock(&pqueue->parallel.lock);
75 while (!list_empty(&local_list)) {
76 struct padata_priv *padata;
78 padata = list_entry(local_list.next,
79 struct padata_priv, list);
81 list_del_init(&padata->list);
83 padata->parallel(padata);
90 * padata_do_parallel - padata parallelization function
92 * @pinst: padata instance
93 * @padata: object to be parallelized
94 * @cb_cpu: pointer to the CPU that the serialization callback function should
95 * run on. If it's not in the serial cpumask of @pinst
96 * (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
97 * none found, returns -EINVAL.
99 * The parallelization callback function will run with BHs off.
100 * Note: Every object which is parallelized by padata_do_parallel
101 * must be seen by padata_do_serial.
103 int padata_do_parallel(struct padata_instance *pinst,
104 struct padata_priv *padata, int *cb_cpu)
106 int i, cpu, cpu_index, target_cpu, err;
107 struct padata_parallel_queue *queue;
108 struct parallel_data *pd;
112 pd = rcu_dereference_bh(pinst->pd);
115 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
118 if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
119 if (!cpumask_weight(pd->cpumask.cbcpu))
122 /* Select an alternate fallback CPU and notify the caller. */
123 cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
125 cpu = cpumask_first(pd->cpumask.cbcpu);
126 for (i = 0; i < cpu_index; i++)
127 cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
133 if ((pinst->flags & PADATA_RESET))
136 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
140 atomic_inc(&pd->refcnt);
142 padata->cb_cpu = *cb_cpu;
144 padata->seq_nr = atomic_inc_return(&pd->seq_nr);
145 target_cpu = padata_cpu_hash(pd, padata->seq_nr);
146 padata->cpu = target_cpu;
147 queue = per_cpu_ptr(pd->pqueue, target_cpu);
149 spin_lock(&queue->parallel.lock);
150 list_add_tail(&padata->list, &queue->parallel.list);
151 spin_unlock(&queue->parallel.lock);
153 queue_work(pinst->parallel_wq, &queue->work);
156 rcu_read_unlock_bh();
160 EXPORT_SYMBOL(padata_do_parallel);
163 * padata_find_next - Find the next object that needs serialization.
167 * A pointer to the control struct of the next object that needs
168 * serialization, if present in one of the percpu reorder queues.
170 * NULL, if the next object that needs serialization will
171 * be parallel processed by another cpu and is not yet present in
172 * the cpu's reorder queue.
174 static struct padata_priv *padata_find_next(struct parallel_data *pd,
177 struct padata_parallel_queue *next_queue;
178 struct padata_priv *padata;
179 struct padata_list *reorder;
182 next_queue = per_cpu_ptr(pd->pqueue, cpu);
183 reorder = &next_queue->reorder;
185 spin_lock(&reorder->lock);
186 if (list_empty(&reorder->list)) {
187 spin_unlock(&reorder->lock);
191 padata = list_entry(reorder->list.next, struct padata_priv, list);
194 * Checks the rare case where two or more parallel jobs have hashed to
195 * the same CPU and one of the later ones finishes first.
197 if (padata->seq_nr != pd->processed) {
198 spin_unlock(&reorder->lock);
203 list_del_init(&padata->list);
204 atomic_dec(&pd->reorder_objects);
206 pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
209 spin_unlock(&reorder->lock);
213 static void padata_reorder(struct parallel_data *pd)
216 struct padata_priv *padata;
217 struct padata_serial_queue *squeue;
218 struct padata_instance *pinst = pd->pinst;
219 struct padata_parallel_queue *next_queue;
222 * We need to ensure that only one cpu can work on dequeueing of
223 * the reorder queue the time. Calculating in which percpu reorder
224 * queue the next object will arrive takes some time. A spinlock
225 * would be highly contended. Also it is not clear in which order
226 * the objects arrive to the reorder queues. So a cpu could wait to
227 * get the lock just to notice that there is nothing to do at the
228 * moment. Therefore we use a trylock and let the holder of the lock
229 * care for all the objects enqueued during the holdtime of the lock.
231 if (!spin_trylock_bh(&pd->lock))
235 padata = padata_find_next(pd, true);
238 * If the next object that needs serialization is parallel
239 * processed by another cpu and is still on it's way to the
240 * cpu's reorder queue, nothing to do for now.
245 cb_cpu = padata->cb_cpu;
246 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
248 spin_lock(&squeue->serial.lock);
249 list_add_tail(&padata->list, &squeue->serial.list);
250 spin_unlock(&squeue->serial.lock);
252 queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
255 spin_unlock_bh(&pd->lock);
258 * The next object that needs serialization might have arrived to
259 * the reorder queues in the meantime.
261 * Ensure reorder queue is read after pd->lock is dropped so we see
262 * new objects from another task in padata_do_serial. Pairs with
263 * smp_mb__after_atomic in padata_do_serial.
267 next_queue = per_cpu_ptr(pd->pqueue, pd->cpu);
268 if (!list_empty(&next_queue->reorder.list) &&
269 padata_find_next(pd, false))
270 queue_work(pinst->serial_wq, &pd->reorder_work);
273 static void invoke_padata_reorder(struct work_struct *work)
275 struct parallel_data *pd;
278 pd = container_of(work, struct parallel_data, reorder_work);
283 static void padata_serial_worker(struct work_struct *serial_work)
285 struct padata_serial_queue *squeue;
286 struct parallel_data *pd;
287 LIST_HEAD(local_list);
291 squeue = container_of(serial_work, struct padata_serial_queue, work);
294 spin_lock(&squeue->serial.lock);
295 list_replace_init(&squeue->serial.list, &local_list);
296 spin_unlock(&squeue->serial.lock);
300 while (!list_empty(&local_list)) {
301 struct padata_priv *padata;
303 padata = list_entry(local_list.next,
304 struct padata_priv, list);
306 list_del_init(&padata->list);
308 padata->serial(padata);
313 if (atomic_sub_and_test(cnt, &pd->refcnt))
318 * padata_do_serial - padata serialization function
320 * @padata: object to be serialized.
322 * padata_do_serial must be called for every parallelized object.
323 * The serialization callback function will run with BHs off.
325 void padata_do_serial(struct padata_priv *padata)
327 struct parallel_data *pd = padata->pd;
328 struct padata_parallel_queue *pqueue = per_cpu_ptr(pd->pqueue,
330 struct padata_priv *cur;
332 spin_lock(&pqueue->reorder.lock);
333 /* Sort in ascending order of sequence number. */
334 list_for_each_entry_reverse(cur, &pqueue->reorder.list, list)
335 if (cur->seq_nr < padata->seq_nr)
337 list_add(&padata->list, &cur->list);
338 atomic_inc(&pd->reorder_objects);
339 spin_unlock(&pqueue->reorder.lock);
342 * Ensure the addition to the reorder list is ordered correctly
343 * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
346 smp_mb__after_atomic();
350 EXPORT_SYMBOL(padata_do_serial);
352 static int padata_setup_cpumasks(struct parallel_data *pd,
353 const struct cpumask *pcpumask,
354 const struct cpumask *cbcpumask)
356 struct workqueue_attrs *attrs;
359 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
361 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
363 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
365 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
367 attrs = alloc_workqueue_attrs();
369 goto free_cbcpu_mask;
371 /* Restrict parallel_wq workers to pd->cpumask.pcpu. */
372 cpumask_copy(attrs->cpumask, pd->cpumask.pcpu);
373 err = apply_workqueue_attrs(pd->pinst->parallel_wq, attrs);
374 free_workqueue_attrs(attrs);
376 goto free_cbcpu_mask;
381 free_cpumask_var(pd->cpumask.cbcpu);
383 free_cpumask_var(pd->cpumask.pcpu);
388 static void __padata_list_init(struct padata_list *pd_list)
390 INIT_LIST_HEAD(&pd_list->list);
391 spin_lock_init(&pd_list->lock);
394 /* Initialize all percpu queues used by serial workers */
395 static void padata_init_squeues(struct parallel_data *pd)
398 struct padata_serial_queue *squeue;
400 for_each_cpu(cpu, pd->cpumask.cbcpu) {
401 squeue = per_cpu_ptr(pd->squeue, cpu);
403 __padata_list_init(&squeue->serial);
404 INIT_WORK(&squeue->work, padata_serial_worker);
408 /* Initialize all percpu queues used by parallel workers */
409 static void padata_init_pqueues(struct parallel_data *pd)
412 struct padata_parallel_queue *pqueue;
414 for_each_cpu(cpu, pd->cpumask.pcpu) {
415 pqueue = per_cpu_ptr(pd->pqueue, cpu);
417 __padata_list_init(&pqueue->reorder);
418 __padata_list_init(&pqueue->parallel);
419 INIT_WORK(&pqueue->work, padata_parallel_worker);
420 atomic_set(&pqueue->num_obj, 0);
424 /* Allocate and initialize the internal cpumask dependend resources. */
425 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
426 const struct cpumask *pcpumask,
427 const struct cpumask *cbcpumask)
429 struct parallel_data *pd;
431 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
435 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
439 pd->squeue = alloc_percpu(struct padata_serial_queue);
441 goto err_free_pqueue;
444 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
445 goto err_free_squeue;
447 padata_init_pqueues(pd);
448 padata_init_squeues(pd);
449 atomic_set(&pd->seq_nr, -1);
450 atomic_set(&pd->reorder_objects, 0);
451 atomic_set(&pd->refcnt, 1);
452 spin_lock_init(&pd->lock);
453 pd->cpu = cpumask_first(pd->cpumask.pcpu);
454 INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
459 free_percpu(pd->squeue);
461 free_percpu(pd->pqueue);
468 static void padata_free_pd(struct parallel_data *pd)
470 free_cpumask_var(pd->cpumask.pcpu);
471 free_cpumask_var(pd->cpumask.cbcpu);
472 free_percpu(pd->pqueue);
473 free_percpu(pd->squeue);
477 static void __padata_start(struct padata_instance *pinst)
479 pinst->flags |= PADATA_INIT;
482 static void __padata_stop(struct padata_instance *pinst)
484 if (!(pinst->flags & PADATA_INIT))
487 pinst->flags &= ~PADATA_INIT;
492 /* Replace the internal control structure with a new one. */
493 static void padata_replace(struct padata_instance *pinst,
494 struct parallel_data *pd_new)
496 struct parallel_data *pd_old = pinst->pd;
497 int notification_mask = 0;
499 pinst->flags |= PADATA_RESET;
501 rcu_assign_pointer(pinst->pd, pd_new);
505 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
506 notification_mask |= PADATA_CPU_PARALLEL;
507 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
508 notification_mask |= PADATA_CPU_SERIAL;
510 if (atomic_dec_and_test(&pd_old->refcnt))
511 padata_free_pd(pd_old);
513 if (notification_mask)
514 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
518 pinst->flags &= ~PADATA_RESET;
522 * padata_register_cpumask_notifier - Registers a notifier that will be called
523 * if either pcpu or cbcpu or both cpumasks change.
525 * @pinst: A poineter to padata instance
526 * @nblock: A pointer to notifier block.
528 int padata_register_cpumask_notifier(struct padata_instance *pinst,
529 struct notifier_block *nblock)
531 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
534 EXPORT_SYMBOL(padata_register_cpumask_notifier);
537 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
538 * registered earlier using padata_register_cpumask_notifier
540 * @pinst: A pointer to data instance.
541 * @nlock: A pointer to notifier block.
543 int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
544 struct notifier_block *nblock)
546 return blocking_notifier_chain_unregister(
547 &pinst->cpumask_change_notifier,
550 EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
553 /* If cpumask contains no active cpu, we mark the instance as invalid. */
554 static bool padata_validate_cpumask(struct padata_instance *pinst,
555 const struct cpumask *cpumask)
557 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
558 pinst->flags |= PADATA_INVALID;
562 pinst->flags &= ~PADATA_INVALID;
566 static int __padata_set_cpumasks(struct padata_instance *pinst,
567 cpumask_var_t pcpumask,
568 cpumask_var_t cbcpumask)
571 struct parallel_data *pd;
573 valid = padata_validate_cpumask(pinst, pcpumask);
575 __padata_stop(pinst);
579 valid = padata_validate_cpumask(pinst, cbcpumask);
581 __padata_stop(pinst);
584 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
588 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
589 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
591 padata_replace(pinst, pd);
594 __padata_start(pinst);
600 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
601 * equivalent to @cpumask.
603 * @pinst: padata instance
604 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
605 * to parallel and serial cpumasks respectively.
606 * @cpumask: the cpumask to use
608 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
609 cpumask_var_t cpumask)
611 struct cpumask *serial_mask, *parallel_mask;
614 mutex_lock(&pinst->lock);
617 switch (cpumask_type) {
618 case PADATA_CPU_PARALLEL:
619 serial_mask = pinst->cpumask.cbcpu;
620 parallel_mask = cpumask;
622 case PADATA_CPU_SERIAL:
623 parallel_mask = pinst->cpumask.pcpu;
624 serial_mask = cpumask;
630 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
634 mutex_unlock(&pinst->lock);
638 EXPORT_SYMBOL(padata_set_cpumask);
641 * padata_start - start the parallel processing
643 * @pinst: padata instance to start
645 int padata_start(struct padata_instance *pinst)
649 mutex_lock(&pinst->lock);
651 if (pinst->flags & PADATA_INVALID)
654 __padata_start(pinst);
656 mutex_unlock(&pinst->lock);
660 EXPORT_SYMBOL(padata_start);
663 * padata_stop - stop the parallel processing
665 * @pinst: padata instance to stop
667 void padata_stop(struct padata_instance *pinst)
669 mutex_lock(&pinst->lock);
670 __padata_stop(pinst);
671 mutex_unlock(&pinst->lock);
673 EXPORT_SYMBOL(padata_stop);
675 #ifdef CONFIG_HOTPLUG_CPU
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);
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);
697 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
699 struct parallel_data *pd = NULL;
701 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
703 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
704 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
705 __padata_stop(pinst);
707 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
708 pinst->cpumask.cbcpu);
712 padata_replace(pinst, pd);
714 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
715 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
722 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
725 * @pinst: padata instance
726 * @cpu: cpu to remove
727 * @mask: bitmask specifying from which cpumask @cpu should be removed
728 * The @mask may be any combination of the following flags:
729 * PADATA_CPU_SERIAL - serial cpumask
730 * PADATA_CPU_PARALLEL - parallel cpumask
732 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
736 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
739 mutex_lock(&pinst->lock);
742 if (mask & PADATA_CPU_SERIAL)
743 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
744 if (mask & PADATA_CPU_PARALLEL)
745 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
747 err = __padata_remove_cpu(pinst, cpu);
750 mutex_unlock(&pinst->lock);
754 EXPORT_SYMBOL(padata_remove_cpu);
756 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
758 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
759 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
762 static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
764 struct padata_instance *pinst;
767 pinst = hlist_entry_safe(node, struct padata_instance, node);
768 if (!pinst_has_cpu(pinst, cpu))
771 mutex_lock(&pinst->lock);
772 ret = __padata_add_cpu(pinst, cpu);
773 mutex_unlock(&pinst->lock);
777 static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
779 struct padata_instance *pinst;
782 pinst = hlist_entry_safe(node, struct padata_instance, node);
783 if (!pinst_has_cpu(pinst, cpu))
786 mutex_lock(&pinst->lock);
787 ret = __padata_remove_cpu(pinst, cpu);
788 mutex_unlock(&pinst->lock);
792 static enum cpuhp_state hp_online;
795 static void __padata_free(struct padata_instance *pinst)
797 #ifdef CONFIG_HOTPLUG_CPU
798 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
802 padata_free_pd(pinst->pd);
803 free_cpumask_var(pinst->cpumask.pcpu);
804 free_cpumask_var(pinst->cpumask.cbcpu);
805 destroy_workqueue(pinst->serial_wq);
806 destroy_workqueue(pinst->parallel_wq);
810 #define kobj2pinst(_kobj) \
811 container_of(_kobj, struct padata_instance, kobj)
812 #define attr2pentry(_attr) \
813 container_of(_attr, struct padata_sysfs_entry, attr)
815 static void padata_sysfs_release(struct kobject *kobj)
817 struct padata_instance *pinst = kobj2pinst(kobj);
818 __padata_free(pinst);
821 struct padata_sysfs_entry {
822 struct attribute attr;
823 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
824 ssize_t (*store)(struct padata_instance *, struct attribute *,
825 const char *, size_t);
828 static ssize_t show_cpumask(struct padata_instance *pinst,
829 struct attribute *attr, char *buf)
831 struct cpumask *cpumask;
834 mutex_lock(&pinst->lock);
835 if (!strcmp(attr->name, "serial_cpumask"))
836 cpumask = pinst->cpumask.cbcpu;
838 cpumask = pinst->cpumask.pcpu;
840 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
841 nr_cpu_ids, cpumask_bits(cpumask));
842 mutex_unlock(&pinst->lock);
843 return len < PAGE_SIZE ? len : -EINVAL;
846 static ssize_t store_cpumask(struct padata_instance *pinst,
847 struct attribute *attr,
848 const char *buf, size_t count)
850 cpumask_var_t new_cpumask;
854 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
857 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
862 mask_type = !strcmp(attr->name, "serial_cpumask") ?
863 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
864 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
869 free_cpumask_var(new_cpumask);
873 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \
874 static struct padata_sysfs_entry _name##_attr = \
875 __ATTR(_name, 0644, _show_name, _store_name)
876 #define PADATA_ATTR_RO(_name, _show_name) \
877 static struct padata_sysfs_entry _name##_attr = \
878 __ATTR(_name, 0400, _show_name, NULL)
880 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
881 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
884 * Padata sysfs provides the following objects:
885 * serial_cpumask [RW] - cpumask for serial workers
886 * parallel_cpumask [RW] - cpumask for parallel workers
888 static struct attribute *padata_default_attrs[] = {
889 &serial_cpumask_attr.attr,
890 ¶llel_cpumask_attr.attr,
893 ATTRIBUTE_GROUPS(padata_default);
895 static ssize_t padata_sysfs_show(struct kobject *kobj,
896 struct attribute *attr, char *buf)
898 struct padata_instance *pinst;
899 struct padata_sysfs_entry *pentry;
902 pinst = kobj2pinst(kobj);
903 pentry = attr2pentry(attr);
905 ret = pentry->show(pinst, attr, buf);
910 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
911 const char *buf, size_t count)
913 struct padata_instance *pinst;
914 struct padata_sysfs_entry *pentry;
917 pinst = kobj2pinst(kobj);
918 pentry = attr2pentry(attr);
920 ret = pentry->store(pinst, attr, buf, count);
925 static const struct sysfs_ops padata_sysfs_ops = {
926 .show = padata_sysfs_show,
927 .store = padata_sysfs_store,
930 static struct kobj_type padata_attr_type = {
931 .sysfs_ops = &padata_sysfs_ops,
932 .default_groups = padata_default_groups,
933 .release = padata_sysfs_release,
937 * padata_alloc - allocate and initialize a padata instance and specify
938 * cpumasks for serial and parallel workers.
940 * @name: used to identify the instance
941 * @pcpumask: cpumask that will be used for padata parallelization
942 * @cbcpumask: cpumask that will be used for padata serialization
944 static struct padata_instance *padata_alloc(const char *name,
945 const struct cpumask *pcpumask,
946 const struct cpumask *cbcpumask)
948 struct padata_instance *pinst;
949 struct parallel_data *pd = NULL;
951 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
955 pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
957 if (!pinst->parallel_wq)
962 pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
963 WQ_CPU_INTENSIVE, 1, name);
964 if (!pinst->serial_wq)
967 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
968 goto err_free_serial_wq;
969 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
970 free_cpumask_var(pinst->cpumask.pcpu);
971 goto err_free_serial_wq;
973 if (!padata_validate_cpumask(pinst, pcpumask) ||
974 !padata_validate_cpumask(pinst, cbcpumask))
977 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
981 rcu_assign_pointer(pinst->pd, pd);
983 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
984 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
988 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
989 kobject_init(&pinst->kobj, &padata_attr_type);
990 mutex_init(&pinst->lock);
992 #ifdef CONFIG_HOTPLUG_CPU
993 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
1001 free_cpumask_var(pinst->cpumask.pcpu);
1002 free_cpumask_var(pinst->cpumask.cbcpu);
1004 destroy_workqueue(pinst->serial_wq);
1007 destroy_workqueue(pinst->parallel_wq);
1015 * padata_alloc_possible - Allocate and initialize padata instance.
1016 * Use the cpu_possible_mask for serial and
1019 * @name: used to identify the instance
1021 struct padata_instance *padata_alloc_possible(const char *name)
1023 return padata_alloc(name, cpu_possible_mask, cpu_possible_mask);
1025 EXPORT_SYMBOL(padata_alloc_possible);
1028 * padata_free - free a padata instance
1030 * @padata_inst: padata instance to free
1032 void padata_free(struct padata_instance *pinst)
1034 kobject_put(&pinst->kobj);
1036 EXPORT_SYMBOL(padata_free);
1038 #ifdef CONFIG_HOTPLUG_CPU
1040 static __init int padata_driver_init(void)
1044 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1046 padata_cpu_prep_down);
1052 module_init(padata_driver_init);
1054 static __exit void padata_driver_exit(void)
1056 cpuhp_remove_multi_state(hp_online);
1058 module_exit(padata_driver_exit);