1 // SPDX-License-Identifier: GPL-2.0
3 * padata.c - generic interface to process data streams in parallel
5 * See Documentation/core-api/padata.rst for more information.
7 * Copyright (C) 2008, 2009 secunet Security Networks AG
8 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
10 * Copyright (c) 2020 Oracle and/or its affiliates.
11 * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
14 #include <linux/completion.h>
15 #include <linux/export.h>
16 #include <linux/cpumask.h>
17 #include <linux/err.h>
18 #include <linux/cpu.h>
19 #include <linux/padata.h>
20 #include <linux/mutex.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/sysfs.h>
24 #include <linux/rcupdate.h>
26 #define PADATA_WORK_ONSTACK 1 /* Work's memory is on stack */
29 struct work_struct pw_work
;
30 struct list_head pw_list
; /* padata_free_works linkage */
34 static DEFINE_SPINLOCK(padata_works_lock
);
35 static struct padata_work
*padata_works
;
36 static LIST_HEAD(padata_free_works
);
38 struct padata_mt_job_state
{
40 struct completion completion
;
41 struct padata_mt_job
*job
;
44 unsigned long chunk_size
;
47 static void padata_free_pd(struct parallel_data
*pd
);
48 static void __init
padata_mt_helper(struct work_struct
*work
);
50 static int padata_index_to_cpu(struct parallel_data
*pd
, int cpu_index
)
54 target_cpu
= cpumask_first(pd
->cpumask
.pcpu
);
55 for (cpu
= 0; cpu
< cpu_index
; cpu
++)
56 target_cpu
= cpumask_next(target_cpu
, pd
->cpumask
.pcpu
);
61 static int padata_cpu_hash(struct parallel_data
*pd
, unsigned int seq_nr
)
64 * Hash the sequence numbers to the cpus by taking
65 * seq_nr mod. number of cpus in use.
67 int cpu_index
= seq_nr
% cpumask_weight(pd
->cpumask
.pcpu
);
69 return padata_index_to_cpu(pd
, cpu_index
);
72 static struct padata_work
*padata_work_alloc(void)
74 struct padata_work
*pw
;
76 lockdep_assert_held(&padata_works_lock
);
78 if (list_empty(&padata_free_works
))
79 return NULL
; /* No more work items allowed to be queued. */
81 pw
= list_first_entry(&padata_free_works
, struct padata_work
, pw_list
);
82 list_del(&pw
->pw_list
);
86 static void padata_work_init(struct padata_work
*pw
, work_func_t work_fn
,
87 void *data
, int flags
)
89 if (flags
& PADATA_WORK_ONSTACK
)
90 INIT_WORK_ONSTACK(&pw
->pw_work
, work_fn
);
92 INIT_WORK(&pw
->pw_work
, work_fn
);
96 static int __init
padata_work_alloc_mt(int nworks
, void *data
,
97 struct list_head
*head
)
101 spin_lock(&padata_works_lock
);
102 /* Start at 1 because the current task participates in the job. */
103 for (i
= 1; i
< nworks
; ++i
) {
104 struct padata_work
*pw
= padata_work_alloc();
108 padata_work_init(pw
, padata_mt_helper
, data
, 0);
109 list_add(&pw
->pw_list
, head
);
111 spin_unlock(&padata_works_lock
);
116 static void padata_work_free(struct padata_work
*pw
)
118 lockdep_assert_held(&padata_works_lock
);
119 list_add(&pw
->pw_list
, &padata_free_works
);
122 static void __init
padata_works_free(struct list_head
*works
)
124 struct padata_work
*cur
, *next
;
126 if (list_empty(works
))
129 spin_lock(&padata_works_lock
);
130 list_for_each_entry_safe(cur
, next
, works
, pw_list
) {
131 list_del(&cur
->pw_list
);
132 padata_work_free(cur
);
134 spin_unlock(&padata_works_lock
);
137 static void padata_parallel_worker(struct work_struct
*parallel_work
)
139 struct padata_work
*pw
= container_of(parallel_work
, struct padata_work
,
141 struct padata_priv
*padata
= pw
->pw_data
;
144 padata
->parallel(padata
);
145 spin_lock(&padata_works_lock
);
146 padata_work_free(pw
);
147 spin_unlock(&padata_works_lock
);
152 * padata_do_parallel - padata parallelization function
155 * @padata: object to be parallelized
156 * @cb_cpu: pointer to the CPU that the serialization callback function should
157 * run on. If it's not in the serial cpumask of @pinst
158 * (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
159 * none found, returns -EINVAL.
161 * The parallelization callback function will run with BHs off.
162 * Note: Every object which is parallelized by padata_do_parallel
163 * must be seen by padata_do_serial.
165 * Return: 0 on success or else negative error code.
167 int padata_do_parallel(struct padata_shell
*ps
,
168 struct padata_priv
*padata
, int *cb_cpu
)
170 struct padata_instance
*pinst
= ps
->pinst
;
171 int i
, cpu
, cpu_index
, err
;
172 struct parallel_data
*pd
;
173 struct padata_work
*pw
;
177 pd
= rcu_dereference_bh(ps
->pd
);
180 if (!(pinst
->flags
& PADATA_INIT
) || pinst
->flags
& PADATA_INVALID
)
183 if (!cpumask_test_cpu(*cb_cpu
, pd
->cpumask
.cbcpu
)) {
184 if (cpumask_empty(pd
->cpumask
.cbcpu
))
187 /* Select an alternate fallback CPU and notify the caller. */
188 cpu_index
= *cb_cpu
% cpumask_weight(pd
->cpumask
.cbcpu
);
190 cpu
= cpumask_first(pd
->cpumask
.cbcpu
);
191 for (i
= 0; i
< cpu_index
; i
++)
192 cpu
= cpumask_next(cpu
, pd
->cpumask
.cbcpu
);
198 if ((pinst
->flags
& PADATA_RESET
))
201 refcount_inc(&pd
->refcnt
);
203 padata
->cb_cpu
= *cb_cpu
;
205 spin_lock(&padata_works_lock
);
206 padata
->seq_nr
= ++pd
->seq_nr
;
207 pw
= padata_work_alloc();
208 spin_unlock(&padata_works_lock
);
210 rcu_read_unlock_bh();
213 padata_work_init(pw
, padata_parallel_worker
, padata
, 0);
214 queue_work(pinst
->parallel_wq
, &pw
->pw_work
);
216 /* Maximum works limit exceeded, run in the current task. */
217 padata
->parallel(padata
);
222 rcu_read_unlock_bh();
226 EXPORT_SYMBOL(padata_do_parallel
);
229 * padata_find_next - Find the next object that needs serialization.
232 * * A pointer to the control struct of the next object that needs
233 * serialization, if present in one of the percpu reorder queues.
234 * * NULL, if the next object that needs serialization will
235 * be parallel processed by another cpu and is not yet present in
236 * the cpu's reorder queue.
238 static struct padata_priv
*padata_find_next(struct parallel_data
*pd
,
241 struct padata_priv
*padata
;
242 struct padata_list
*reorder
;
245 reorder
= per_cpu_ptr(pd
->reorder_list
, cpu
);
247 spin_lock(&reorder
->lock
);
248 if (list_empty(&reorder
->list
)) {
249 spin_unlock(&reorder
->lock
);
253 padata
= list_entry(reorder
->list
.next
, struct padata_priv
, list
);
256 * Checks the rare case where two or more parallel jobs have hashed to
257 * the same CPU and one of the later ones finishes first.
259 if (padata
->seq_nr
!= pd
->processed
) {
260 spin_unlock(&reorder
->lock
);
265 list_del_init(&padata
->list
);
267 pd
->cpu
= cpumask_next_wrap(cpu
, pd
->cpumask
.pcpu
, -1, false);
270 spin_unlock(&reorder
->lock
);
274 static void padata_reorder(struct parallel_data
*pd
)
276 struct padata_instance
*pinst
= pd
->ps
->pinst
;
278 struct padata_priv
*padata
;
279 struct padata_serial_queue
*squeue
;
280 struct padata_list
*reorder
;
283 * We need to ensure that only one cpu can work on dequeueing of
284 * the reorder queue the time. Calculating in which percpu reorder
285 * queue the next object will arrive takes some time. A spinlock
286 * would be highly contended. Also it is not clear in which order
287 * the objects arrive to the reorder queues. So a cpu could wait to
288 * get the lock just to notice that there is nothing to do at the
289 * moment. Therefore we use a trylock and let the holder of the lock
290 * care for all the objects enqueued during the holdtime of the lock.
292 if (!spin_trylock_bh(&pd
->lock
))
296 padata
= padata_find_next(pd
, true);
299 * If the next object that needs serialization is parallel
300 * processed by another cpu and is still on it's way to the
301 * cpu's reorder queue, nothing to do for now.
306 cb_cpu
= padata
->cb_cpu
;
307 squeue
= per_cpu_ptr(pd
->squeue
, cb_cpu
);
309 spin_lock(&squeue
->serial
.lock
);
310 list_add_tail(&padata
->list
, &squeue
->serial
.list
);
311 spin_unlock(&squeue
->serial
.lock
);
313 queue_work_on(cb_cpu
, pinst
->serial_wq
, &squeue
->work
);
316 spin_unlock_bh(&pd
->lock
);
319 * The next object that needs serialization might have arrived to
320 * the reorder queues in the meantime.
322 * Ensure reorder queue is read after pd->lock is dropped so we see
323 * new objects from another task in padata_do_serial. Pairs with
324 * smp_mb in padata_do_serial.
328 reorder
= per_cpu_ptr(pd
->reorder_list
, pd
->cpu
);
329 if (!list_empty(&reorder
->list
) && padata_find_next(pd
, false))
330 queue_work(pinst
->serial_wq
, &pd
->reorder_work
);
333 static void invoke_padata_reorder(struct work_struct
*work
)
335 struct parallel_data
*pd
;
338 pd
= container_of(work
, struct parallel_data
, reorder_work
);
343 static void padata_serial_worker(struct work_struct
*serial_work
)
345 struct padata_serial_queue
*squeue
;
346 struct parallel_data
*pd
;
347 LIST_HEAD(local_list
);
351 squeue
= container_of(serial_work
, struct padata_serial_queue
, work
);
354 spin_lock(&squeue
->serial
.lock
);
355 list_replace_init(&squeue
->serial
.list
, &local_list
);
356 spin_unlock(&squeue
->serial
.lock
);
360 while (!list_empty(&local_list
)) {
361 struct padata_priv
*padata
;
363 padata
= list_entry(local_list
.next
,
364 struct padata_priv
, list
);
366 list_del_init(&padata
->list
);
368 padata
->serial(padata
);
373 if (refcount_sub_and_test(cnt
, &pd
->refcnt
))
378 * padata_do_serial - padata serialization function
380 * @padata: object to be serialized.
382 * padata_do_serial must be called for every parallelized object.
383 * The serialization callback function will run with BHs off.
385 void padata_do_serial(struct padata_priv
*padata
)
387 struct parallel_data
*pd
= padata
->pd
;
388 int hashed_cpu
= padata_cpu_hash(pd
, padata
->seq_nr
);
389 struct padata_list
*reorder
= per_cpu_ptr(pd
->reorder_list
, hashed_cpu
);
390 struct padata_priv
*cur
;
392 spin_lock(&reorder
->lock
);
393 /* Sort in ascending order of sequence number. */
394 list_for_each_entry_reverse(cur
, &reorder
->list
, list
)
395 if (cur
->seq_nr
< padata
->seq_nr
)
397 list_add(&padata
->list
, &cur
->list
);
398 spin_unlock(&reorder
->lock
);
401 * Ensure the addition to the reorder list is ordered correctly
402 * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
409 EXPORT_SYMBOL(padata_do_serial
);
411 static int padata_setup_cpumasks(struct padata_instance
*pinst
)
413 struct workqueue_attrs
*attrs
;
416 attrs
= alloc_workqueue_attrs();
420 /* Restrict parallel_wq workers to pd->cpumask.pcpu. */
421 cpumask_copy(attrs
->cpumask
, pinst
->cpumask
.pcpu
);
422 err
= apply_workqueue_attrs(pinst
->parallel_wq
, attrs
);
423 free_workqueue_attrs(attrs
);
428 static void __init
padata_mt_helper(struct work_struct
*w
)
430 struct padata_work
*pw
= container_of(w
, struct padata_work
, pw_work
);
431 struct padata_mt_job_state
*ps
= pw
->pw_data
;
432 struct padata_mt_job
*job
= ps
->job
;
435 spin_lock(&ps
->lock
);
437 while (job
->size
> 0) {
438 unsigned long start
, size
, end
;
441 /* So end is chunk size aligned if enough work remains. */
442 size
= roundup(start
+ 1, ps
->chunk_size
) - start
;
443 size
= min(size
, job
->size
);
449 spin_unlock(&ps
->lock
);
450 job
->thread_fn(start
, end
, job
->fn_arg
);
451 spin_lock(&ps
->lock
);
455 done
= (ps
->nworks_fini
== ps
->nworks
);
456 spin_unlock(&ps
->lock
);
459 complete(&ps
->completion
);
463 * padata_do_multithreaded - run a multithreaded job
464 * @job: Description of the job.
466 * See the definition of struct padata_mt_job for more details.
468 void __init
padata_do_multithreaded(struct padata_mt_job
*job
)
470 /* In case threads finish at different times. */
471 static const unsigned long load_balance_factor
= 4;
472 struct padata_work my_work
, *pw
;
473 struct padata_mt_job_state ps
;
480 /* Ensure at least one thread when size < min_chunk. */
481 nworks
= max(job
->size
/ job
->min_chunk
, 1ul);
482 nworks
= min(nworks
, job
->max_threads
);
485 /* Single thread, no coordination needed, cut to the chase. */
486 job
->thread_fn(job
->start
, job
->start
+ job
->size
, job
->fn_arg
);
490 spin_lock_init(&ps
.lock
);
491 init_completion(&ps
.completion
);
493 ps
.nworks
= padata_work_alloc_mt(nworks
, &ps
, &works
);
497 * Chunk size is the amount of work a helper does per call to the
498 * thread function. Load balance large jobs between threads by
499 * increasing the number of chunks, guarantee at least the minimum
500 * chunk size from the caller, and honor the caller's alignment.
502 ps
.chunk_size
= job
->size
/ (ps
.nworks
* load_balance_factor
);
503 ps
.chunk_size
= max(ps
.chunk_size
, job
->min_chunk
);
504 ps
.chunk_size
= roundup(ps
.chunk_size
, job
->align
);
506 list_for_each_entry(pw
, &works
, pw_list
)
507 queue_work(system_unbound_wq
, &pw
->pw_work
);
509 /* Use the current thread, which saves starting a workqueue worker. */
510 padata_work_init(&my_work
, padata_mt_helper
, &ps
, PADATA_WORK_ONSTACK
);
511 padata_mt_helper(&my_work
.pw_work
);
513 /* Wait for all the helpers to finish. */
514 wait_for_completion(&ps
.completion
);
516 destroy_work_on_stack(&my_work
.pw_work
);
517 padata_works_free(&works
);
520 static void __padata_list_init(struct padata_list
*pd_list
)
522 INIT_LIST_HEAD(&pd_list
->list
);
523 spin_lock_init(&pd_list
->lock
);
526 /* Initialize all percpu queues used by serial workers */
527 static void padata_init_squeues(struct parallel_data
*pd
)
530 struct padata_serial_queue
*squeue
;
532 for_each_cpu(cpu
, pd
->cpumask
.cbcpu
) {
533 squeue
= per_cpu_ptr(pd
->squeue
, cpu
);
535 __padata_list_init(&squeue
->serial
);
536 INIT_WORK(&squeue
->work
, padata_serial_worker
);
540 /* Initialize per-CPU reorder lists */
541 static void padata_init_reorder_list(struct parallel_data
*pd
)
544 struct padata_list
*list
;
546 for_each_cpu(cpu
, pd
->cpumask
.pcpu
) {
547 list
= per_cpu_ptr(pd
->reorder_list
, cpu
);
548 __padata_list_init(list
);
552 /* Allocate and initialize the internal cpumask dependend resources. */
553 static struct parallel_data
*padata_alloc_pd(struct padata_shell
*ps
)
555 struct padata_instance
*pinst
= ps
->pinst
;
556 struct parallel_data
*pd
;
558 pd
= kzalloc(sizeof(struct parallel_data
), GFP_KERNEL
);
562 pd
->reorder_list
= alloc_percpu(struct padata_list
);
563 if (!pd
->reorder_list
)
566 pd
->squeue
= alloc_percpu(struct padata_serial_queue
);
568 goto err_free_reorder_list
;
572 if (!alloc_cpumask_var(&pd
->cpumask
.pcpu
, GFP_KERNEL
))
573 goto err_free_squeue
;
574 if (!alloc_cpumask_var(&pd
->cpumask
.cbcpu
, GFP_KERNEL
))
577 cpumask_and(pd
->cpumask
.pcpu
, pinst
->cpumask
.pcpu
, cpu_online_mask
);
578 cpumask_and(pd
->cpumask
.cbcpu
, pinst
->cpumask
.cbcpu
, cpu_online_mask
);
580 padata_init_reorder_list(pd
);
581 padata_init_squeues(pd
);
583 refcount_set(&pd
->refcnt
, 1);
584 spin_lock_init(&pd
->lock
);
585 pd
->cpu
= cpumask_first(pd
->cpumask
.pcpu
);
586 INIT_WORK(&pd
->reorder_work
, invoke_padata_reorder
);
591 free_cpumask_var(pd
->cpumask
.pcpu
);
593 free_percpu(pd
->squeue
);
594 err_free_reorder_list
:
595 free_percpu(pd
->reorder_list
);
602 static void padata_free_pd(struct parallel_data
*pd
)
604 free_cpumask_var(pd
->cpumask
.pcpu
);
605 free_cpumask_var(pd
->cpumask
.cbcpu
);
606 free_percpu(pd
->reorder_list
);
607 free_percpu(pd
->squeue
);
611 static void __padata_start(struct padata_instance
*pinst
)
613 pinst
->flags
|= PADATA_INIT
;
616 static void __padata_stop(struct padata_instance
*pinst
)
618 if (!(pinst
->flags
& PADATA_INIT
))
621 pinst
->flags
&= ~PADATA_INIT
;
626 /* Replace the internal control structure with a new one. */
627 static int padata_replace_one(struct padata_shell
*ps
)
629 struct parallel_data
*pd_new
;
631 pd_new
= padata_alloc_pd(ps
);
635 ps
->opd
= rcu_dereference_protected(ps
->pd
, 1);
636 rcu_assign_pointer(ps
->pd
, pd_new
);
641 static int padata_replace(struct padata_instance
*pinst
)
643 struct padata_shell
*ps
;
646 pinst
->flags
|= PADATA_RESET
;
648 list_for_each_entry(ps
, &pinst
->pslist
, list
) {
649 err
= padata_replace_one(ps
);
656 list_for_each_entry_continue_reverse(ps
, &pinst
->pslist
, list
)
657 if (refcount_dec_and_test(&ps
->opd
->refcnt
))
658 padata_free_pd(ps
->opd
);
660 pinst
->flags
&= ~PADATA_RESET
;
665 /* If cpumask contains no active cpu, we mark the instance as invalid. */
666 static bool padata_validate_cpumask(struct padata_instance
*pinst
,
667 const struct cpumask
*cpumask
)
669 if (!cpumask_intersects(cpumask
, cpu_online_mask
)) {
670 pinst
->flags
|= PADATA_INVALID
;
674 pinst
->flags
&= ~PADATA_INVALID
;
678 static int __padata_set_cpumasks(struct padata_instance
*pinst
,
679 cpumask_var_t pcpumask
,
680 cpumask_var_t cbcpumask
)
685 valid
= padata_validate_cpumask(pinst
, pcpumask
);
687 __padata_stop(pinst
);
691 valid
= padata_validate_cpumask(pinst
, cbcpumask
);
693 __padata_stop(pinst
);
696 cpumask_copy(pinst
->cpumask
.pcpu
, pcpumask
);
697 cpumask_copy(pinst
->cpumask
.cbcpu
, cbcpumask
);
699 err
= padata_setup_cpumasks(pinst
) ?: padata_replace(pinst
);
702 __padata_start(pinst
);
708 * padata_set_cpumask - Sets specified by @cpumask_type cpumask to the value
709 * equivalent to @cpumask.
710 * @pinst: padata instance
711 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
712 * to parallel and serial cpumasks respectively.
713 * @cpumask: the cpumask to use
715 * Return: 0 on success or negative error code
717 int padata_set_cpumask(struct padata_instance
*pinst
, int cpumask_type
,
718 cpumask_var_t cpumask
)
720 struct cpumask
*serial_mask
, *parallel_mask
;
724 mutex_lock(&pinst
->lock
);
726 switch (cpumask_type
) {
727 case PADATA_CPU_PARALLEL
:
728 serial_mask
= pinst
->cpumask
.cbcpu
;
729 parallel_mask
= cpumask
;
731 case PADATA_CPU_SERIAL
:
732 parallel_mask
= pinst
->cpumask
.pcpu
;
733 serial_mask
= cpumask
;
739 err
= __padata_set_cpumasks(pinst
, parallel_mask
, serial_mask
);
742 mutex_unlock(&pinst
->lock
);
747 EXPORT_SYMBOL(padata_set_cpumask
);
749 #ifdef CONFIG_HOTPLUG_CPU
751 static int __padata_add_cpu(struct padata_instance
*pinst
, int cpu
)
755 if (cpumask_test_cpu(cpu
, cpu_online_mask
)) {
756 err
= padata_replace(pinst
);
758 if (padata_validate_cpumask(pinst
, pinst
->cpumask
.pcpu
) &&
759 padata_validate_cpumask(pinst
, pinst
->cpumask
.cbcpu
))
760 __padata_start(pinst
);
766 static int __padata_remove_cpu(struct padata_instance
*pinst
, int cpu
)
770 if (!cpumask_test_cpu(cpu
, cpu_online_mask
)) {
771 if (!padata_validate_cpumask(pinst
, pinst
->cpumask
.pcpu
) ||
772 !padata_validate_cpumask(pinst
, pinst
->cpumask
.cbcpu
))
773 __padata_stop(pinst
);
775 err
= padata_replace(pinst
);
781 static inline int pinst_has_cpu(struct padata_instance
*pinst
, int cpu
)
783 return cpumask_test_cpu(cpu
, pinst
->cpumask
.pcpu
) ||
784 cpumask_test_cpu(cpu
, pinst
->cpumask
.cbcpu
);
787 static int padata_cpu_online(unsigned int cpu
, struct hlist_node
*node
)
789 struct padata_instance
*pinst
;
792 pinst
= hlist_entry_safe(node
, struct padata_instance
, cpu_online_node
);
793 if (!pinst_has_cpu(pinst
, cpu
))
796 mutex_lock(&pinst
->lock
);
797 ret
= __padata_add_cpu(pinst
, cpu
);
798 mutex_unlock(&pinst
->lock
);
802 static int padata_cpu_dead(unsigned int cpu
, struct hlist_node
*node
)
804 struct padata_instance
*pinst
;
807 pinst
= hlist_entry_safe(node
, struct padata_instance
, cpu_dead_node
);
808 if (!pinst_has_cpu(pinst
, cpu
))
811 mutex_lock(&pinst
->lock
);
812 ret
= __padata_remove_cpu(pinst
, cpu
);
813 mutex_unlock(&pinst
->lock
);
817 static enum cpuhp_state hp_online
;
820 static void __padata_free(struct padata_instance
*pinst
)
822 #ifdef CONFIG_HOTPLUG_CPU
823 cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD
,
824 &pinst
->cpu_dead_node
);
825 cpuhp_state_remove_instance_nocalls(hp_online
, &pinst
->cpu_online_node
);
828 WARN_ON(!list_empty(&pinst
->pslist
));
830 free_cpumask_var(pinst
->cpumask
.pcpu
);
831 free_cpumask_var(pinst
->cpumask
.cbcpu
);
832 destroy_workqueue(pinst
->serial_wq
);
833 destroy_workqueue(pinst
->parallel_wq
);
837 #define kobj2pinst(_kobj) \
838 container_of(_kobj, struct padata_instance, kobj)
839 #define attr2pentry(_attr) \
840 container_of(_attr, struct padata_sysfs_entry, attr)
842 static void padata_sysfs_release(struct kobject
*kobj
)
844 struct padata_instance
*pinst
= kobj2pinst(kobj
);
845 __padata_free(pinst
);
848 struct padata_sysfs_entry
{
849 struct attribute attr
;
850 ssize_t (*show
)(struct padata_instance
*, struct attribute
*, char *);
851 ssize_t (*store
)(struct padata_instance
*, struct attribute
*,
852 const char *, size_t);
855 static ssize_t
show_cpumask(struct padata_instance
*pinst
,
856 struct attribute
*attr
, char *buf
)
858 struct cpumask
*cpumask
;
861 mutex_lock(&pinst
->lock
);
862 if (!strcmp(attr
->name
, "serial_cpumask"))
863 cpumask
= pinst
->cpumask
.cbcpu
;
865 cpumask
= pinst
->cpumask
.pcpu
;
867 len
= snprintf(buf
, PAGE_SIZE
, "%*pb\n",
868 nr_cpu_ids
, cpumask_bits(cpumask
));
869 mutex_unlock(&pinst
->lock
);
870 return len
< PAGE_SIZE
? len
: -EINVAL
;
873 static ssize_t
store_cpumask(struct padata_instance
*pinst
,
874 struct attribute
*attr
,
875 const char *buf
, size_t count
)
877 cpumask_var_t new_cpumask
;
881 if (!alloc_cpumask_var(&new_cpumask
, GFP_KERNEL
))
884 ret
= bitmap_parse(buf
, count
, cpumask_bits(new_cpumask
),
889 mask_type
= !strcmp(attr
->name
, "serial_cpumask") ?
890 PADATA_CPU_SERIAL
: PADATA_CPU_PARALLEL
;
891 ret
= padata_set_cpumask(pinst
, mask_type
, new_cpumask
);
896 free_cpumask_var(new_cpumask
);
900 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \
901 static struct padata_sysfs_entry _name##_attr = \
902 __ATTR(_name, 0644, _show_name, _store_name)
903 #define PADATA_ATTR_RO(_name, _show_name) \
904 static struct padata_sysfs_entry _name##_attr = \
905 __ATTR(_name, 0400, _show_name, NULL)
907 PADATA_ATTR_RW(serial_cpumask
, show_cpumask
, store_cpumask
);
908 PADATA_ATTR_RW(parallel_cpumask
, show_cpumask
, store_cpumask
);
911 * Padata sysfs provides the following objects:
912 * serial_cpumask [RW] - cpumask for serial workers
913 * parallel_cpumask [RW] - cpumask for parallel workers
915 static struct attribute
*padata_default_attrs
[] = {
916 &serial_cpumask_attr
.attr
,
917 ¶llel_cpumask_attr
.attr
,
920 ATTRIBUTE_GROUPS(padata_default
);
922 static ssize_t
padata_sysfs_show(struct kobject
*kobj
,
923 struct attribute
*attr
, char *buf
)
925 struct padata_instance
*pinst
;
926 struct padata_sysfs_entry
*pentry
;
929 pinst
= kobj2pinst(kobj
);
930 pentry
= attr2pentry(attr
);
932 ret
= pentry
->show(pinst
, attr
, buf
);
937 static ssize_t
padata_sysfs_store(struct kobject
*kobj
, struct attribute
*attr
,
938 const char *buf
, size_t count
)
940 struct padata_instance
*pinst
;
941 struct padata_sysfs_entry
*pentry
;
944 pinst
= kobj2pinst(kobj
);
945 pentry
= attr2pentry(attr
);
947 ret
= pentry
->store(pinst
, attr
, buf
, count
);
952 static const struct sysfs_ops padata_sysfs_ops
= {
953 .show
= padata_sysfs_show
,
954 .store
= padata_sysfs_store
,
957 static struct kobj_type padata_attr_type
= {
958 .sysfs_ops
= &padata_sysfs_ops
,
959 .default_groups
= padata_default_groups
,
960 .release
= padata_sysfs_release
,
964 * padata_alloc - allocate and initialize a padata instance
965 * @name: used to identify the instance
967 * Return: new instance on success, NULL on error
969 struct padata_instance
*padata_alloc(const char *name
)
971 struct padata_instance
*pinst
;
973 pinst
= kzalloc(sizeof(struct padata_instance
), GFP_KERNEL
);
977 pinst
->parallel_wq
= alloc_workqueue("%s_parallel", WQ_UNBOUND
, 0,
979 if (!pinst
->parallel_wq
)
984 pinst
->serial_wq
= alloc_workqueue("%s_serial", WQ_MEM_RECLAIM
|
985 WQ_CPU_INTENSIVE
, 1, name
);
986 if (!pinst
->serial_wq
)
989 if (!alloc_cpumask_var(&pinst
->cpumask
.pcpu
, GFP_KERNEL
))
990 goto err_free_serial_wq
;
991 if (!alloc_cpumask_var(&pinst
->cpumask
.cbcpu
, GFP_KERNEL
)) {
992 free_cpumask_var(pinst
->cpumask
.pcpu
);
993 goto err_free_serial_wq
;
996 INIT_LIST_HEAD(&pinst
->pslist
);
998 cpumask_copy(pinst
->cpumask
.pcpu
, cpu_possible_mask
);
999 cpumask_copy(pinst
->cpumask
.cbcpu
, cpu_possible_mask
);
1001 if (padata_setup_cpumasks(pinst
))
1002 goto err_free_masks
;
1004 __padata_start(pinst
);
1006 kobject_init(&pinst
->kobj
, &padata_attr_type
);
1007 mutex_init(&pinst
->lock
);
1009 #ifdef CONFIG_HOTPLUG_CPU
1010 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online
,
1011 &pinst
->cpu_online_node
);
1012 cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD
,
1013 &pinst
->cpu_dead_node
);
1021 free_cpumask_var(pinst
->cpumask
.pcpu
);
1022 free_cpumask_var(pinst
->cpumask
.cbcpu
);
1024 destroy_workqueue(pinst
->serial_wq
);
1027 destroy_workqueue(pinst
->parallel_wq
);
1033 EXPORT_SYMBOL(padata_alloc
);
1036 * padata_free - free a padata instance
1038 * @pinst: padata instance to free
1040 void padata_free(struct padata_instance
*pinst
)
1042 kobject_put(&pinst
->kobj
);
1044 EXPORT_SYMBOL(padata_free
);
1047 * padata_alloc_shell - Allocate and initialize padata shell.
1049 * @pinst: Parent padata_instance object.
1051 * Return: new shell on success, NULL on error
1053 struct padata_shell
*padata_alloc_shell(struct padata_instance
*pinst
)
1055 struct parallel_data
*pd
;
1056 struct padata_shell
*ps
;
1058 ps
= kzalloc(sizeof(*ps
), GFP_KERNEL
);
1065 pd
= padata_alloc_pd(ps
);
1071 mutex_lock(&pinst
->lock
);
1072 RCU_INIT_POINTER(ps
->pd
, pd
);
1073 list_add(&ps
->list
, &pinst
->pslist
);
1074 mutex_unlock(&pinst
->lock
);
1083 EXPORT_SYMBOL(padata_alloc_shell
);
1086 * padata_free_shell - free a padata shell
1088 * @ps: padata shell to free
1090 void padata_free_shell(struct padata_shell
*ps
)
1095 mutex_lock(&ps
->pinst
->lock
);
1096 list_del(&ps
->list
);
1097 padata_free_pd(rcu_dereference_protected(ps
->pd
, 1));
1098 mutex_unlock(&ps
->pinst
->lock
);
1102 EXPORT_SYMBOL(padata_free_shell
);
1104 void __init
padata_init(void)
1106 unsigned int i
, possible_cpus
;
1107 #ifdef CONFIG_HOTPLUG_CPU
1110 ret
= cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN
, "padata:online",
1111 padata_cpu_online
, NULL
);
1116 ret
= cpuhp_setup_state_multi(CPUHP_PADATA_DEAD
, "padata:dead",
1117 NULL
, padata_cpu_dead
);
1119 goto remove_online_state
;
1122 possible_cpus
= num_possible_cpus();
1123 padata_works
= kmalloc_array(possible_cpus
, sizeof(struct padata_work
),
1126 goto remove_dead_state
;
1128 for (i
= 0; i
< possible_cpus
; ++i
)
1129 list_add(&padata_works
[i
].pw_list
, &padata_free_works
);
1134 #ifdef CONFIG_HOTPLUG_CPU
1135 cpuhp_remove_multi_state(CPUHP_PADATA_DEAD
);
1136 remove_online_state
:
1137 cpuhp_remove_multi_state(hp_online
);
1140 pr_warn("padata: initialization failed\n");