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 int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
42 target_cpu = cpumask_first(pd->cpumask.pcpu);
43 for (cpu = 0; cpu < cpu_index; cpu++)
44 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
49 static int padata_cpu_hash(struct parallel_data *pd)
55 * Hash the sequence numbers to the cpus by taking
56 * seq_nr mod. number of cpus in use.
59 seq_nr = atomic_inc_return(&pd->seq_nr);
60 cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
62 return padata_index_to_cpu(pd, cpu_index);
65 static void padata_parallel_worker(struct work_struct *parallel_work)
67 struct padata_parallel_queue *pqueue;
68 LIST_HEAD(local_list);
71 pqueue = container_of(parallel_work,
72 struct padata_parallel_queue, work);
74 spin_lock(&pqueue->parallel.lock);
75 list_replace_init(&pqueue->parallel.list, &local_list);
76 spin_unlock(&pqueue->parallel.lock);
78 while (!list_empty(&local_list)) {
79 struct padata_priv *padata;
81 padata = list_entry(local_list.next,
82 struct padata_priv, list);
84 list_del_init(&padata->list);
86 padata->parallel(padata);
93 * padata_do_parallel - padata parallelization function
95 * @pinst: padata instance
96 * @padata: object to be parallelized
97 * @cb_cpu: cpu the serialization callback function will run on,
98 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
100 * The parallelization callback function will run with BHs off.
101 * Note: Every object which is parallelized by padata_do_parallel
102 * must be seen by padata_do_serial.
104 int padata_do_parallel(struct padata_instance *pinst,
105 struct padata_priv *padata, int cb_cpu)
108 struct padata_parallel_queue *queue;
109 struct parallel_data *pd;
113 pd = rcu_dereference_bh(pinst->pd);
116 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
119 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
123 if ((pinst->flags & PADATA_RESET))
126 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
130 atomic_inc(&pd->refcnt);
132 padata->cb_cpu = cb_cpu;
134 target_cpu = padata_cpu_hash(pd);
135 padata->cpu = target_cpu;
136 queue = per_cpu_ptr(pd->pqueue, target_cpu);
138 spin_lock(&queue->parallel.lock);
139 list_add_tail(&padata->list, &queue->parallel.list);
140 spin_unlock(&queue->parallel.lock);
142 queue_work_on(target_cpu, pinst->wq, &queue->work);
145 rcu_read_unlock_bh();
149 EXPORT_SYMBOL(padata_do_parallel);
152 * padata_get_next - Get the next object that needs serialization.
156 * A pointer to the control struct of the next object that needs
157 * serialization, if present in one of the percpu reorder queues.
159 * -EINPROGRESS, if the next object that needs serialization will
160 * be parallel processed by another cpu and is not yet present in
161 * the cpu's reorder queue.
163 * -ENODATA, if this cpu has to do the parallel processing for
166 static struct padata_priv *padata_get_next(struct parallel_data *pd)
168 struct padata_parallel_queue *next_queue;
169 struct padata_priv *padata;
170 struct padata_list *reorder;
173 next_queue = per_cpu_ptr(pd->pqueue, cpu);
174 reorder = &next_queue->reorder;
176 spin_lock(&reorder->lock);
177 if (!list_empty(&reorder->list)) {
178 padata = list_entry(reorder->list.next,
179 struct padata_priv, list);
181 list_del_init(&padata->list);
182 atomic_dec(&pd->reorder_objects);
184 pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1,
187 spin_unlock(&reorder->lock);
190 spin_unlock(&reorder->lock);
192 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
193 padata = ERR_PTR(-ENODATA);
197 padata = ERR_PTR(-EINPROGRESS);
202 static void padata_reorder(struct parallel_data *pd)
205 struct padata_priv *padata;
206 struct padata_serial_queue *squeue;
207 struct padata_instance *pinst = pd->pinst;
208 struct padata_parallel_queue *next_queue;
211 * We need to ensure that only one cpu can work on dequeueing of
212 * the reorder queue the time. Calculating in which percpu reorder
213 * queue the next object will arrive takes some time. A spinlock
214 * would be highly contended. Also it is not clear in which order
215 * the objects arrive to the reorder queues. So a cpu could wait to
216 * get the lock just to notice that there is nothing to do at the
217 * moment. Therefore we use a trylock and let the holder of the lock
218 * care for all the objects enqueued during the holdtime of the lock.
220 if (!spin_trylock_bh(&pd->lock))
224 padata = padata_get_next(pd);
227 * If the next object that needs serialization is parallel
228 * processed by another cpu and is still on it's way to the
229 * cpu's reorder queue, nothing to do for now.
231 if (PTR_ERR(padata) == -EINPROGRESS)
235 * This cpu has to do the parallel processing of the next
236 * object. It's waiting in the cpu's parallelization queue,
237 * so exit immediately.
239 if (PTR_ERR(padata) == -ENODATA) {
240 spin_unlock_bh(&pd->lock);
244 cb_cpu = padata->cb_cpu;
245 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
247 spin_lock(&squeue->serial.lock);
248 list_add_tail(&padata->list, &squeue->serial.list);
249 spin_unlock(&squeue->serial.lock);
251 queue_work_on(cb_cpu, pinst->wq, &squeue->work);
254 spin_unlock_bh(&pd->lock);
257 * The next object that needs serialization might have arrived to
258 * the reorder queues in the meantime.
260 * Ensure reorder queue is read after pd->lock is dropped so we see
261 * new objects from another task in padata_do_serial. Pairs with
262 * smp_mb__after_atomic in padata_do_serial.
266 next_queue = per_cpu_ptr(pd->pqueue, pd->cpu);
267 if (!list_empty(&next_queue->reorder.list))
268 queue_work(pinst->wq, &pd->reorder_work);
271 static void invoke_padata_reorder(struct work_struct *work)
273 struct parallel_data *pd;
276 pd = container_of(work, struct parallel_data, reorder_work);
281 static void padata_serial_worker(struct work_struct *serial_work)
283 struct padata_serial_queue *squeue;
284 struct parallel_data *pd;
285 LIST_HEAD(local_list);
288 squeue = container_of(serial_work, struct padata_serial_queue, work);
291 spin_lock(&squeue->serial.lock);
292 list_replace_init(&squeue->serial.list, &local_list);
293 spin_unlock(&squeue->serial.lock);
295 while (!list_empty(&local_list)) {
296 struct padata_priv *padata;
298 padata = list_entry(local_list.next,
299 struct padata_priv, list);
301 list_del_init(&padata->list);
303 padata->serial(padata);
304 atomic_dec(&pd->refcnt);
310 * padata_do_serial - padata serialization function
312 * @padata: object to be serialized.
314 * padata_do_serial must be called for every parallelized object.
315 * The serialization callback function will run with BHs off.
317 void padata_do_serial(struct padata_priv *padata)
319 struct parallel_data *pd = padata->pd;
320 struct padata_parallel_queue *pqueue = per_cpu_ptr(pd->pqueue,
323 spin_lock(&pqueue->reorder.lock);
324 list_add_tail(&padata->list, &pqueue->reorder.list);
325 atomic_inc(&pd->reorder_objects);
326 spin_unlock(&pqueue->reorder.lock);
329 * Ensure the addition to the reorder list is ordered correctly
330 * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
333 smp_mb__after_atomic();
337 EXPORT_SYMBOL(padata_do_serial);
339 static int padata_setup_cpumasks(struct parallel_data *pd,
340 const struct cpumask *pcpumask,
341 const struct cpumask *cbcpumask)
343 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
346 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
347 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
348 free_cpumask_var(pd->cpumask.pcpu);
352 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
356 static void __padata_list_init(struct padata_list *pd_list)
358 INIT_LIST_HEAD(&pd_list->list);
359 spin_lock_init(&pd_list->lock);
362 /* Initialize all percpu queues used by serial workers */
363 static void padata_init_squeues(struct parallel_data *pd)
366 struct padata_serial_queue *squeue;
368 for_each_cpu(cpu, pd->cpumask.cbcpu) {
369 squeue = per_cpu_ptr(pd->squeue, cpu);
371 __padata_list_init(&squeue->serial);
372 INIT_WORK(&squeue->work, padata_serial_worker);
376 /* Initialize all percpu queues used by parallel workers */
377 static void padata_init_pqueues(struct parallel_data *pd)
380 struct padata_parallel_queue *pqueue;
383 for_each_possible_cpu(cpu) {
384 pqueue = per_cpu_ptr(pd->pqueue, cpu);
386 if (!cpumask_test_cpu(cpu, pd->cpumask.pcpu)) {
387 pqueue->cpu_index = -1;
391 pqueue->cpu_index = cpu_index;
394 __padata_list_init(&pqueue->reorder);
395 __padata_list_init(&pqueue->parallel);
396 INIT_WORK(&pqueue->work, padata_parallel_worker);
397 atomic_set(&pqueue->num_obj, 0);
401 /* Allocate and initialize the internal cpumask dependend resources. */
402 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
403 const struct cpumask *pcpumask,
404 const struct cpumask *cbcpumask)
406 struct parallel_data *pd;
408 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
412 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
416 pd->squeue = alloc_percpu(struct padata_serial_queue);
418 goto err_free_pqueue;
419 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
420 goto err_free_squeue;
422 padata_init_pqueues(pd);
423 padata_init_squeues(pd);
424 atomic_set(&pd->seq_nr, -1);
425 atomic_set(&pd->reorder_objects, 0);
426 atomic_set(&pd->refcnt, 0);
428 spin_lock_init(&pd->lock);
429 pd->cpu = cpumask_first(pd->cpumask.pcpu);
430 INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
435 free_percpu(pd->squeue);
437 free_percpu(pd->pqueue);
444 static void padata_free_pd(struct parallel_data *pd)
446 free_cpumask_var(pd->cpumask.pcpu);
447 free_cpumask_var(pd->cpumask.cbcpu);
448 free_percpu(pd->pqueue);
449 free_percpu(pd->squeue);
453 /* Flush all objects out of the padata queues. */
454 static void padata_flush_queues(struct parallel_data *pd)
457 struct padata_parallel_queue *pqueue;
458 struct padata_serial_queue *squeue;
460 for_each_cpu(cpu, pd->cpumask.pcpu) {
461 pqueue = per_cpu_ptr(pd->pqueue, cpu);
462 flush_work(&pqueue->work);
465 if (atomic_read(&pd->reorder_objects))
468 for_each_cpu(cpu, pd->cpumask.cbcpu) {
469 squeue = per_cpu_ptr(pd->squeue, cpu);
470 flush_work(&squeue->work);
473 BUG_ON(atomic_read(&pd->refcnt) != 0);
476 static void __padata_start(struct padata_instance *pinst)
478 pinst->flags |= PADATA_INIT;
481 static void __padata_stop(struct padata_instance *pinst)
483 if (!(pinst->flags & PADATA_INIT))
486 pinst->flags &= ~PADATA_INIT;
491 padata_flush_queues(pinst->pd);
495 /* Replace the internal control structure with a new one. */
496 static void padata_replace(struct padata_instance *pinst,
497 struct parallel_data *pd_new)
499 struct parallel_data *pd_old = pinst->pd;
500 int notification_mask = 0;
502 pinst->flags |= PADATA_RESET;
504 rcu_assign_pointer(pinst->pd, pd_new);
508 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
509 notification_mask |= PADATA_CPU_PARALLEL;
510 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
511 notification_mask |= PADATA_CPU_SERIAL;
513 padata_flush_queues(pd_old);
514 padata_free_pd(pd_old);
516 if (notification_mask)
517 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
521 pinst->flags &= ~PADATA_RESET;
525 * padata_register_cpumask_notifier - Registers a notifier that will be called
526 * if either pcpu or cbcpu or both cpumasks change.
528 * @pinst: A poineter to padata instance
529 * @nblock: A pointer to notifier block.
531 int padata_register_cpumask_notifier(struct padata_instance *pinst,
532 struct notifier_block *nblock)
534 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
537 EXPORT_SYMBOL(padata_register_cpumask_notifier);
540 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
541 * registered earlier using padata_register_cpumask_notifier
543 * @pinst: A pointer to data instance.
544 * @nlock: A pointer to notifier block.
546 int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
547 struct notifier_block *nblock)
549 return blocking_notifier_chain_unregister(
550 &pinst->cpumask_change_notifier,
553 EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
556 /* If cpumask contains no active cpu, we mark the instance as invalid. */
557 static bool padata_validate_cpumask(struct padata_instance *pinst,
558 const struct cpumask *cpumask)
560 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
561 pinst->flags |= PADATA_INVALID;
565 pinst->flags &= ~PADATA_INVALID;
569 static int __padata_set_cpumasks(struct padata_instance *pinst,
570 cpumask_var_t pcpumask,
571 cpumask_var_t cbcpumask)
574 struct parallel_data *pd;
576 valid = padata_validate_cpumask(pinst, pcpumask);
578 __padata_stop(pinst);
582 valid = padata_validate_cpumask(pinst, cbcpumask);
584 __padata_stop(pinst);
587 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
591 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
592 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
594 padata_replace(pinst, pd);
597 __padata_start(pinst);
603 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
604 * equivalent to @cpumask.
606 * @pinst: padata instance
607 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
608 * to parallel and serial cpumasks respectively.
609 * @cpumask: the cpumask to use
611 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
612 cpumask_var_t cpumask)
614 struct cpumask *serial_mask, *parallel_mask;
617 mutex_lock(&pinst->lock);
620 switch (cpumask_type) {
621 case PADATA_CPU_PARALLEL:
622 serial_mask = pinst->cpumask.cbcpu;
623 parallel_mask = cpumask;
625 case PADATA_CPU_SERIAL:
626 parallel_mask = pinst->cpumask.pcpu;
627 serial_mask = cpumask;
633 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
637 mutex_unlock(&pinst->lock);
641 EXPORT_SYMBOL(padata_set_cpumask);
644 * padata_start - start the parallel processing
646 * @pinst: padata instance to start
648 int padata_start(struct padata_instance *pinst)
652 mutex_lock(&pinst->lock);
654 if (pinst->flags & PADATA_INVALID)
657 __padata_start(pinst);
659 mutex_unlock(&pinst->lock);
663 EXPORT_SYMBOL(padata_start);
666 * padata_stop - stop the parallel processing
668 * @pinst: padata instance to stop
670 void padata_stop(struct padata_instance *pinst)
672 mutex_lock(&pinst->lock);
673 __padata_stop(pinst);
674 mutex_unlock(&pinst->lock);
676 EXPORT_SYMBOL(padata_stop);
678 #ifdef CONFIG_HOTPLUG_CPU
680 static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
682 struct parallel_data *pd;
684 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
685 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
686 pinst->cpumask.cbcpu);
690 padata_replace(pinst, pd);
692 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
693 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
694 __padata_start(pinst);
700 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
702 struct parallel_data *pd = NULL;
704 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
706 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
707 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
708 __padata_stop(pinst);
710 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
711 pinst->cpumask.cbcpu);
715 padata_replace(pinst, pd);
717 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
718 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
725 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
728 * @pinst: padata instance
729 * @cpu: cpu to remove
730 * @mask: bitmask specifying from which cpumask @cpu should be removed
731 * The @mask may be any combination of the following flags:
732 * PADATA_CPU_SERIAL - serial cpumask
733 * PADATA_CPU_PARALLEL - parallel cpumask
735 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
739 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
742 mutex_lock(&pinst->lock);
745 if (mask & PADATA_CPU_SERIAL)
746 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
747 if (mask & PADATA_CPU_PARALLEL)
748 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
750 err = __padata_remove_cpu(pinst, cpu);
753 mutex_unlock(&pinst->lock);
757 EXPORT_SYMBOL(padata_remove_cpu);
759 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
761 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
762 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
765 static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
767 struct padata_instance *pinst;
770 pinst = hlist_entry_safe(node, struct padata_instance, node);
771 if (!pinst_has_cpu(pinst, cpu))
774 mutex_lock(&pinst->lock);
775 ret = __padata_add_cpu(pinst, cpu);
776 mutex_unlock(&pinst->lock);
780 static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
782 struct padata_instance *pinst;
785 pinst = hlist_entry_safe(node, struct padata_instance, node);
786 if (!pinst_has_cpu(pinst, cpu))
789 mutex_lock(&pinst->lock);
790 ret = __padata_remove_cpu(pinst, cpu);
791 mutex_unlock(&pinst->lock);
795 static enum cpuhp_state hp_online;
798 static void __padata_free(struct padata_instance *pinst)
800 #ifdef CONFIG_HOTPLUG_CPU
801 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
805 padata_free_pd(pinst->pd);
806 free_cpumask_var(pinst->cpumask.pcpu);
807 free_cpumask_var(pinst->cpumask.cbcpu);
808 destroy_workqueue(pinst->wq);
812 #define kobj2pinst(_kobj) \
813 container_of(_kobj, struct padata_instance, kobj)
814 #define attr2pentry(_attr) \
815 container_of(_attr, struct padata_sysfs_entry, attr)
817 static void padata_sysfs_release(struct kobject *kobj)
819 struct padata_instance *pinst = kobj2pinst(kobj);
820 __padata_free(pinst);
823 struct padata_sysfs_entry {
824 struct attribute attr;
825 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
826 ssize_t (*store)(struct padata_instance *, struct attribute *,
827 const char *, size_t);
830 static ssize_t show_cpumask(struct padata_instance *pinst,
831 struct attribute *attr, char *buf)
833 struct cpumask *cpumask;
836 mutex_lock(&pinst->lock);
837 if (!strcmp(attr->name, "serial_cpumask"))
838 cpumask = pinst->cpumask.cbcpu;
840 cpumask = pinst->cpumask.pcpu;
842 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
843 nr_cpu_ids, cpumask_bits(cpumask));
844 mutex_unlock(&pinst->lock);
845 return len < PAGE_SIZE ? len : -EINVAL;
848 static ssize_t store_cpumask(struct padata_instance *pinst,
849 struct attribute *attr,
850 const char *buf, size_t count)
852 cpumask_var_t new_cpumask;
856 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
859 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
864 mask_type = !strcmp(attr->name, "serial_cpumask") ?
865 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
866 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
871 free_cpumask_var(new_cpumask);
875 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \
876 static struct padata_sysfs_entry _name##_attr = \
877 __ATTR(_name, 0644, _show_name, _store_name)
878 #define PADATA_ATTR_RO(_name, _show_name) \
879 static struct padata_sysfs_entry _name##_attr = \
880 __ATTR(_name, 0400, _show_name, NULL)
882 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
883 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
886 * Padata sysfs provides the following objects:
887 * serial_cpumask [RW] - cpumask for serial workers
888 * parallel_cpumask [RW] - cpumask for parallel workers
890 static struct attribute *padata_default_attrs[] = {
891 &serial_cpumask_attr.attr,
892 ¶llel_cpumask_attr.attr,
895 ATTRIBUTE_GROUPS(padata_default);
897 static ssize_t padata_sysfs_show(struct kobject *kobj,
898 struct attribute *attr, char *buf)
900 struct padata_instance *pinst;
901 struct padata_sysfs_entry *pentry;
904 pinst = kobj2pinst(kobj);
905 pentry = attr2pentry(attr);
907 ret = pentry->show(pinst, attr, buf);
912 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
913 const char *buf, size_t count)
915 struct padata_instance *pinst;
916 struct padata_sysfs_entry *pentry;
919 pinst = kobj2pinst(kobj);
920 pentry = attr2pentry(attr);
922 ret = pentry->store(pinst, attr, buf, count);
927 static const struct sysfs_ops padata_sysfs_ops = {
928 .show = padata_sysfs_show,
929 .store = padata_sysfs_store,
932 static struct kobj_type padata_attr_type = {
933 .sysfs_ops = &padata_sysfs_ops,
934 .default_groups = padata_default_groups,
935 .release = padata_sysfs_release,
939 * padata_alloc - allocate and initialize a padata instance and specify
940 * cpumasks for serial and parallel workers.
942 * @name: used to identify the instance
943 * @pcpumask: cpumask that will be used for padata parallelization
944 * @cbcpumask: cpumask that will be used for padata serialization
946 * Must be called from a cpus_read_lock() protected region
948 static struct padata_instance *padata_alloc(const char *name,
949 const struct cpumask *pcpumask,
950 const struct cpumask *cbcpumask)
952 struct padata_instance *pinst;
953 struct parallel_data *pd = NULL;
955 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
959 pinst->wq = alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE,
964 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
966 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
967 free_cpumask_var(pinst->cpumask.pcpu);
970 if (!padata_validate_cpumask(pinst, pcpumask) ||
971 !padata_validate_cpumask(pinst, cbcpumask))
974 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
978 rcu_assign_pointer(pinst->pd, pd);
980 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
981 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
985 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
986 kobject_init(&pinst->kobj, &padata_attr_type);
987 mutex_init(&pinst->lock);
989 #ifdef CONFIG_HOTPLUG_CPU
990 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
995 free_cpumask_var(pinst->cpumask.pcpu);
996 free_cpumask_var(pinst->cpumask.cbcpu);
998 destroy_workqueue(pinst->wq);
1006 * padata_alloc_possible - Allocate and initialize padata instance.
1007 * Use the cpu_possible_mask for serial and
1010 * @name: used to identify the instance
1012 * Must be called from a cpus_read_lock() protected region
1014 struct padata_instance *padata_alloc_possible(const char *name)
1016 lockdep_assert_cpus_held();
1017 return padata_alloc(name, cpu_possible_mask, cpu_possible_mask);
1019 EXPORT_SYMBOL(padata_alloc_possible);
1022 * padata_free - free a padata instance
1024 * @padata_inst: padata instance to free
1026 void padata_free(struct padata_instance *pinst)
1028 kobject_put(&pinst->kobj);
1030 EXPORT_SYMBOL(padata_free);
1032 #ifdef CONFIG_HOTPLUG_CPU
1034 static __init int padata_driver_init(void)
1038 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1040 padata_cpu_prep_down);
1046 module_init(padata_driver_init);
1048 static __exit void padata_driver_exit(void)
1050 cpuhp_remove_multi_state(hp_online);
1052 module_exit(padata_driver_exit);