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: pointer to the CPU that the serialization callback function should
98 * run on. If it's not in the serial cpumask of @pinst
99 * (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
100 * none found, returns -EINVAL.
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 i, cpu, cpu_index, target_cpu, err;
110 struct padata_parallel_queue *queue;
111 struct parallel_data *pd;
115 pd = rcu_dereference_bh(pinst->pd);
118 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
121 if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
122 if (!cpumask_weight(pd->cpumask.cbcpu))
125 /* Select an alternate fallback CPU and notify the caller. */
126 cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
128 cpu = cpumask_first(pd->cpumask.cbcpu);
129 for (i = 0; i < cpu_index; i++)
130 cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
136 if ((pinst->flags & PADATA_RESET))
139 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
143 atomic_inc(&pd->refcnt);
145 padata->cb_cpu = *cb_cpu;
147 target_cpu = padata_cpu_hash(pd);
148 padata->cpu = target_cpu;
149 queue = per_cpu_ptr(pd->pqueue, target_cpu);
151 spin_lock(&queue->parallel.lock);
152 list_add_tail(&padata->list, &queue->parallel.list);
153 spin_unlock(&queue->parallel.lock);
155 queue_work_on(target_cpu, pinst->wq, &queue->work);
158 rcu_read_unlock_bh();
162 EXPORT_SYMBOL(padata_do_parallel);
165 * padata_get_next - Get the next object that needs serialization.
169 * A pointer to the control struct of the next object that needs
170 * serialization, if present in one of the percpu reorder queues.
172 * -EINPROGRESS, if the next object that needs serialization will
173 * be parallel processed by another cpu and is not yet present in
174 * the cpu's reorder queue.
176 * -ENODATA, if this cpu has to do the parallel processing for
179 static struct padata_priv *padata_get_next(struct parallel_data *pd)
181 struct padata_parallel_queue *next_queue;
182 struct padata_priv *padata;
183 struct padata_list *reorder;
186 next_queue = per_cpu_ptr(pd->pqueue, cpu);
187 reorder = &next_queue->reorder;
189 spin_lock(&reorder->lock);
190 if (!list_empty(&reorder->list)) {
191 padata = list_entry(reorder->list.next,
192 struct padata_priv, list);
194 list_del_init(&padata->list);
195 atomic_dec(&pd->reorder_objects);
197 pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1,
200 spin_unlock(&reorder->lock);
203 spin_unlock(&reorder->lock);
205 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
206 padata = ERR_PTR(-ENODATA);
210 padata = ERR_PTR(-EINPROGRESS);
215 static void padata_reorder(struct parallel_data *pd)
218 struct padata_priv *padata;
219 struct padata_serial_queue *squeue;
220 struct padata_instance *pinst = pd->pinst;
221 struct padata_parallel_queue *next_queue;
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))
237 padata = padata_get_next(pd);
240 * If the next object that needs serialization is parallel
241 * processed by another cpu and is still on it's way to the
242 * cpu's reorder queue, nothing to do for now.
244 if (PTR_ERR(padata) == -EINPROGRESS)
248 * This cpu has to do the parallel processing of the next
249 * object. It's waiting in the cpu's parallelization queue,
250 * so exit immediately.
252 if (PTR_ERR(padata) == -ENODATA) {
253 spin_unlock_bh(&pd->lock);
257 cb_cpu = padata->cb_cpu;
258 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
260 spin_lock(&squeue->serial.lock);
261 list_add_tail(&padata->list, &squeue->serial.list);
262 spin_unlock(&squeue->serial.lock);
264 queue_work_on(cb_cpu, pinst->wq, &squeue->work);
267 spin_unlock_bh(&pd->lock);
270 * The next object that needs serialization might have arrived to
271 * the reorder queues in the meantime.
273 * Ensure reorder queue is read after pd->lock is dropped so we see
274 * new objects from another task in padata_do_serial. Pairs with
275 * smp_mb__after_atomic in padata_do_serial.
279 next_queue = per_cpu_ptr(pd->pqueue, pd->cpu);
280 if (!list_empty(&next_queue->reorder.list))
281 queue_work(pinst->wq, &pd->reorder_work);
284 static void invoke_padata_reorder(struct work_struct *work)
286 struct parallel_data *pd;
289 pd = container_of(work, struct parallel_data, reorder_work);
294 static void padata_serial_worker(struct work_struct *serial_work)
296 struct padata_serial_queue *squeue;
297 struct parallel_data *pd;
298 LIST_HEAD(local_list);
301 squeue = container_of(serial_work, struct padata_serial_queue, work);
304 spin_lock(&squeue->serial.lock);
305 list_replace_init(&squeue->serial.list, &local_list);
306 spin_unlock(&squeue->serial.lock);
308 while (!list_empty(&local_list)) {
309 struct padata_priv *padata;
311 padata = list_entry(local_list.next,
312 struct padata_priv, list);
314 list_del_init(&padata->list);
316 padata->serial(padata);
317 atomic_dec(&pd->refcnt);
323 * padata_do_serial - padata serialization function
325 * @padata: object to be serialized.
327 * padata_do_serial must be called for every parallelized object.
328 * The serialization callback function will run with BHs off.
330 void padata_do_serial(struct padata_priv *padata)
332 struct parallel_data *pd = padata->pd;
333 struct padata_parallel_queue *pqueue = per_cpu_ptr(pd->pqueue,
336 spin_lock(&pqueue->reorder.lock);
337 list_add_tail(&padata->list, &pqueue->reorder.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 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
359 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
360 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
361 free_cpumask_var(pd->cpumask.pcpu);
365 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
369 static void __padata_list_init(struct padata_list *pd_list)
371 INIT_LIST_HEAD(&pd_list->list);
372 spin_lock_init(&pd_list->lock);
375 /* Initialize all percpu queues used by serial workers */
376 static void padata_init_squeues(struct parallel_data *pd)
379 struct padata_serial_queue *squeue;
381 for_each_cpu(cpu, pd->cpumask.cbcpu) {
382 squeue = per_cpu_ptr(pd->squeue, cpu);
384 __padata_list_init(&squeue->serial);
385 INIT_WORK(&squeue->work, padata_serial_worker);
389 /* Initialize all percpu queues used by parallel workers */
390 static void padata_init_pqueues(struct parallel_data *pd)
393 struct padata_parallel_queue *pqueue;
396 for_each_possible_cpu(cpu) {
397 pqueue = per_cpu_ptr(pd->pqueue, cpu);
399 if (!cpumask_test_cpu(cpu, pd->cpumask.pcpu)) {
400 pqueue->cpu_index = -1;
404 pqueue->cpu_index = cpu_index;
407 __padata_list_init(&pqueue->reorder);
408 __padata_list_init(&pqueue->parallel);
409 INIT_WORK(&pqueue->work, padata_parallel_worker);
410 atomic_set(&pqueue->num_obj, 0);
414 /* Allocate and initialize the internal cpumask dependend resources. */
415 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
416 const struct cpumask *pcpumask,
417 const struct cpumask *cbcpumask)
419 struct parallel_data *pd;
421 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
425 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
429 pd->squeue = alloc_percpu(struct padata_serial_queue);
431 goto err_free_pqueue;
432 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
433 goto err_free_squeue;
435 padata_init_pqueues(pd);
436 padata_init_squeues(pd);
437 atomic_set(&pd->seq_nr, -1);
438 atomic_set(&pd->reorder_objects, 0);
439 atomic_set(&pd->refcnt, 0);
441 spin_lock_init(&pd->lock);
442 pd->cpu = cpumask_first(pd->cpumask.pcpu);
443 INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
448 free_percpu(pd->squeue);
450 free_percpu(pd->pqueue);
457 static void padata_free_pd(struct parallel_data *pd)
459 free_cpumask_var(pd->cpumask.pcpu);
460 free_cpumask_var(pd->cpumask.cbcpu);
461 free_percpu(pd->pqueue);
462 free_percpu(pd->squeue);
466 /* Flush all objects out of the padata queues. */
467 static void padata_flush_queues(struct parallel_data *pd)
470 struct padata_parallel_queue *pqueue;
471 struct padata_serial_queue *squeue;
473 for_each_cpu(cpu, pd->cpumask.pcpu) {
474 pqueue = per_cpu_ptr(pd->pqueue, cpu);
475 flush_work(&pqueue->work);
478 if (atomic_read(&pd->reorder_objects))
481 for_each_cpu(cpu, pd->cpumask.cbcpu) {
482 squeue = per_cpu_ptr(pd->squeue, cpu);
483 flush_work(&squeue->work);
486 BUG_ON(atomic_read(&pd->refcnt) != 0);
489 static void __padata_start(struct padata_instance *pinst)
491 pinst->flags |= PADATA_INIT;
494 static void __padata_stop(struct padata_instance *pinst)
496 if (!(pinst->flags & PADATA_INIT))
499 pinst->flags &= ~PADATA_INIT;
504 padata_flush_queues(pinst->pd);
508 /* Replace the internal control structure with a new one. */
509 static void padata_replace(struct padata_instance *pinst,
510 struct parallel_data *pd_new)
512 struct parallel_data *pd_old = pinst->pd;
513 int notification_mask = 0;
515 pinst->flags |= PADATA_RESET;
517 rcu_assign_pointer(pinst->pd, pd_new);
521 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
522 notification_mask |= PADATA_CPU_PARALLEL;
523 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
524 notification_mask |= PADATA_CPU_SERIAL;
526 padata_flush_queues(pd_old);
527 padata_free_pd(pd_old);
529 if (notification_mask)
530 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
534 pinst->flags &= ~PADATA_RESET;
538 * padata_register_cpumask_notifier - Registers a notifier that will be called
539 * if either pcpu or cbcpu or both cpumasks change.
541 * @pinst: A poineter to padata instance
542 * @nblock: A pointer to notifier block.
544 int padata_register_cpumask_notifier(struct padata_instance *pinst,
545 struct notifier_block *nblock)
547 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
550 EXPORT_SYMBOL(padata_register_cpumask_notifier);
553 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
554 * registered earlier using padata_register_cpumask_notifier
556 * @pinst: A pointer to data instance.
557 * @nlock: A pointer to notifier block.
559 int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
560 struct notifier_block *nblock)
562 return blocking_notifier_chain_unregister(
563 &pinst->cpumask_change_notifier,
566 EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
569 /* If cpumask contains no active cpu, we mark the instance as invalid. */
570 static bool padata_validate_cpumask(struct padata_instance *pinst,
571 const struct cpumask *cpumask)
573 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
574 pinst->flags |= PADATA_INVALID;
578 pinst->flags &= ~PADATA_INVALID;
582 static int __padata_set_cpumasks(struct padata_instance *pinst,
583 cpumask_var_t pcpumask,
584 cpumask_var_t cbcpumask)
587 struct parallel_data *pd;
589 valid = padata_validate_cpumask(pinst, pcpumask);
591 __padata_stop(pinst);
595 valid = padata_validate_cpumask(pinst, cbcpumask);
597 __padata_stop(pinst);
600 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
604 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
605 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
607 padata_replace(pinst, pd);
610 __padata_start(pinst);
616 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
617 * equivalent to @cpumask.
619 * @pinst: padata instance
620 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
621 * to parallel and serial cpumasks respectively.
622 * @cpumask: the cpumask to use
624 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
625 cpumask_var_t cpumask)
627 struct cpumask *serial_mask, *parallel_mask;
630 mutex_lock(&pinst->lock);
633 switch (cpumask_type) {
634 case PADATA_CPU_PARALLEL:
635 serial_mask = pinst->cpumask.cbcpu;
636 parallel_mask = cpumask;
638 case PADATA_CPU_SERIAL:
639 parallel_mask = pinst->cpumask.pcpu;
640 serial_mask = cpumask;
646 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
650 mutex_unlock(&pinst->lock);
654 EXPORT_SYMBOL(padata_set_cpumask);
657 * padata_start - start the parallel processing
659 * @pinst: padata instance to start
661 int padata_start(struct padata_instance *pinst)
665 mutex_lock(&pinst->lock);
667 if (pinst->flags & PADATA_INVALID)
670 __padata_start(pinst);
672 mutex_unlock(&pinst->lock);
676 EXPORT_SYMBOL(padata_start);
679 * padata_stop - stop the parallel processing
681 * @pinst: padata instance to stop
683 void padata_stop(struct padata_instance *pinst)
685 mutex_lock(&pinst->lock);
686 __padata_stop(pinst);
687 mutex_unlock(&pinst->lock);
689 EXPORT_SYMBOL(padata_stop);
691 #ifdef CONFIG_HOTPLUG_CPU
693 static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
695 struct parallel_data *pd;
697 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
698 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
699 pinst->cpumask.cbcpu);
703 padata_replace(pinst, pd);
705 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
706 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
707 __padata_start(pinst);
713 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
715 struct parallel_data *pd = NULL;
717 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
719 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
720 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
721 __padata_stop(pinst);
723 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
724 pinst->cpumask.cbcpu);
728 padata_replace(pinst, pd);
730 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
731 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
738 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
741 * @pinst: padata instance
742 * @cpu: cpu to remove
743 * @mask: bitmask specifying from which cpumask @cpu should be removed
744 * The @mask may be any combination of the following flags:
745 * PADATA_CPU_SERIAL - serial cpumask
746 * PADATA_CPU_PARALLEL - parallel cpumask
748 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
752 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
755 mutex_lock(&pinst->lock);
758 if (mask & PADATA_CPU_SERIAL)
759 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
760 if (mask & PADATA_CPU_PARALLEL)
761 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
763 err = __padata_remove_cpu(pinst, cpu);
766 mutex_unlock(&pinst->lock);
770 EXPORT_SYMBOL(padata_remove_cpu);
772 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
774 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
775 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
778 static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
780 struct padata_instance *pinst;
783 pinst = hlist_entry_safe(node, struct padata_instance, node);
784 if (!pinst_has_cpu(pinst, cpu))
787 mutex_lock(&pinst->lock);
788 ret = __padata_add_cpu(pinst, cpu);
789 mutex_unlock(&pinst->lock);
793 static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
795 struct padata_instance *pinst;
798 pinst = hlist_entry_safe(node, struct padata_instance, node);
799 if (!pinst_has_cpu(pinst, cpu))
802 mutex_lock(&pinst->lock);
803 ret = __padata_remove_cpu(pinst, cpu);
804 mutex_unlock(&pinst->lock);
808 static enum cpuhp_state hp_online;
811 static void __padata_free(struct padata_instance *pinst)
813 #ifdef CONFIG_HOTPLUG_CPU
814 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node);
818 padata_free_pd(pinst->pd);
819 free_cpumask_var(pinst->cpumask.pcpu);
820 free_cpumask_var(pinst->cpumask.cbcpu);
821 destroy_workqueue(pinst->wq);
825 #define kobj2pinst(_kobj) \
826 container_of(_kobj, struct padata_instance, kobj)
827 #define attr2pentry(_attr) \
828 container_of(_attr, struct padata_sysfs_entry, attr)
830 static void padata_sysfs_release(struct kobject *kobj)
832 struct padata_instance *pinst = kobj2pinst(kobj);
833 __padata_free(pinst);
836 struct padata_sysfs_entry {
837 struct attribute attr;
838 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
839 ssize_t (*store)(struct padata_instance *, struct attribute *,
840 const char *, size_t);
843 static ssize_t show_cpumask(struct padata_instance *pinst,
844 struct attribute *attr, char *buf)
846 struct cpumask *cpumask;
849 mutex_lock(&pinst->lock);
850 if (!strcmp(attr->name, "serial_cpumask"))
851 cpumask = pinst->cpumask.cbcpu;
853 cpumask = pinst->cpumask.pcpu;
855 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
856 nr_cpu_ids, cpumask_bits(cpumask));
857 mutex_unlock(&pinst->lock);
858 return len < PAGE_SIZE ? len : -EINVAL;
861 static ssize_t store_cpumask(struct padata_instance *pinst,
862 struct attribute *attr,
863 const char *buf, size_t count)
865 cpumask_var_t new_cpumask;
869 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
872 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
877 mask_type = !strcmp(attr->name, "serial_cpumask") ?
878 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
879 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
884 free_cpumask_var(new_cpumask);
888 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \
889 static struct padata_sysfs_entry _name##_attr = \
890 __ATTR(_name, 0644, _show_name, _store_name)
891 #define PADATA_ATTR_RO(_name, _show_name) \
892 static struct padata_sysfs_entry _name##_attr = \
893 __ATTR(_name, 0400, _show_name, NULL)
895 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
896 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
899 * Padata sysfs provides the following objects:
900 * serial_cpumask [RW] - cpumask for serial workers
901 * parallel_cpumask [RW] - cpumask for parallel workers
903 static struct attribute *padata_default_attrs[] = {
904 &serial_cpumask_attr.attr,
905 ¶llel_cpumask_attr.attr,
908 ATTRIBUTE_GROUPS(padata_default);
910 static ssize_t padata_sysfs_show(struct kobject *kobj,
911 struct attribute *attr, char *buf)
913 struct padata_instance *pinst;
914 struct padata_sysfs_entry *pentry;
917 pinst = kobj2pinst(kobj);
918 pentry = attr2pentry(attr);
920 ret = pentry->show(pinst, attr, buf);
925 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
926 const char *buf, size_t count)
928 struct padata_instance *pinst;
929 struct padata_sysfs_entry *pentry;
932 pinst = kobj2pinst(kobj);
933 pentry = attr2pentry(attr);
935 ret = pentry->store(pinst, attr, buf, count);
940 static const struct sysfs_ops padata_sysfs_ops = {
941 .show = padata_sysfs_show,
942 .store = padata_sysfs_store,
945 static struct kobj_type padata_attr_type = {
946 .sysfs_ops = &padata_sysfs_ops,
947 .default_groups = padata_default_groups,
948 .release = padata_sysfs_release,
952 * padata_alloc - allocate and initialize a padata instance and specify
953 * cpumasks for serial and parallel workers.
955 * @name: used to identify the instance
956 * @pcpumask: cpumask that will be used for padata parallelization
957 * @cbcpumask: cpumask that will be used for padata serialization
959 * Must be called from a cpus_read_lock() protected region
961 static struct padata_instance *padata_alloc(const char *name,
962 const struct cpumask *pcpumask,
963 const struct cpumask *cbcpumask)
965 struct padata_instance *pinst;
966 struct parallel_data *pd = NULL;
968 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
972 pinst->wq = alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE,
977 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
979 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
980 free_cpumask_var(pinst->cpumask.pcpu);
983 if (!padata_validate_cpumask(pinst, pcpumask) ||
984 !padata_validate_cpumask(pinst, cbcpumask))
987 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
991 rcu_assign_pointer(pinst->pd, pd);
993 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
994 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
998 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
999 kobject_init(&pinst->kobj, &padata_attr_type);
1000 mutex_init(&pinst->lock);
1002 #ifdef CONFIG_HOTPLUG_CPU
1003 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
1008 free_cpumask_var(pinst->cpumask.pcpu);
1009 free_cpumask_var(pinst->cpumask.cbcpu);
1011 destroy_workqueue(pinst->wq);
1019 * padata_alloc_possible - Allocate and initialize padata instance.
1020 * Use the cpu_possible_mask for serial and
1023 * @name: used to identify the instance
1025 * Must be called from a cpus_read_lock() protected region
1027 struct padata_instance *padata_alloc_possible(const char *name)
1029 lockdep_assert_cpus_held();
1030 return padata_alloc(name, cpu_possible_mask, cpu_possible_mask);
1032 EXPORT_SYMBOL(padata_alloc_possible);
1035 * padata_free - free a padata instance
1037 * @padata_inst: padata instance to free
1039 void padata_free(struct padata_instance *pinst)
1041 kobject_put(&pinst->kobj);
1043 EXPORT_SYMBOL(padata_free);
1045 #ifdef CONFIG_HOTPLUG_CPU
1047 static __init int padata_driver_init(void)
1051 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
1053 padata_cpu_prep_down);
1059 module_init(padata_driver_init);
1061 static __exit void padata_driver_exit(void)
1063 cpuhp_remove_multi_state(hp_online);
1065 module_exit(padata_driver_exit);