2 * padata.c - generic interface to process data streams in parallel
4 * See Documentation/padata.txt for an api documentation.
6 * Copyright (C) 2008, 2009 secunet Security Networks AG
7 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms and conditions of the GNU General Public License,
11 * version 2, as published by the Free Software Foundation.
13 * This program is distributed in the hope it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
18 * You should have received a copy of the GNU General Public License along with
19 * this program; if not, write to the Free Software Foundation, Inc.,
20 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
23 #include <linux/export.h>
24 #include <linux/cpumask.h>
25 #include <linux/err.h>
26 #include <linux/cpu.h>
27 #include <linux/padata.h>
28 #include <linux/mutex.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31 #include <linux/sysfs.h>
32 #include <linux/rcupdate.h>
34 #define MAX_OBJ_NUM 1000
36 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
40 target_cpu = cpumask_first(pd->cpumask.pcpu);
41 for (cpu = 0; cpu < cpu_index; cpu++)
42 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
47 static int padata_cpu_hash(struct parallel_data *pd)
53 * Hash the sequence numbers to the cpus by taking
54 * seq_nr mod. number of cpus in use.
57 seq_nr = atomic_inc_return(&pd->seq_nr);
58 cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
60 return padata_index_to_cpu(pd, cpu_index);
63 static void padata_parallel_worker(struct work_struct *parallel_work)
65 struct padata_parallel_queue *pqueue;
66 struct parallel_data *pd;
67 struct padata_instance *pinst;
68 LIST_HEAD(local_list);
71 pqueue = container_of(parallel_work,
72 struct padata_parallel_queue, work);
76 spin_lock(&pqueue->parallel.lock);
77 list_replace_init(&pqueue->parallel.list, &local_list);
78 spin_unlock(&pqueue->parallel.lock);
80 while (!list_empty(&local_list)) {
81 struct padata_priv *padata;
83 padata = list_entry(local_list.next,
84 struct padata_priv, list);
86 list_del_init(&padata->list);
88 padata->parallel(padata);
95 * padata_do_parallel - padata parallelization function
97 * @pinst: padata instance
98 * @padata: object to be parallelized
99 * @cb_cpu: cpu the serialization callback function will run on,
100 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
102 * The parallelization callback function will run with BHs off.
103 * Note: Every object which is parallelized by padata_do_parallel
104 * must be seen by padata_do_serial.
106 int padata_do_parallel(struct padata_instance *pinst,
107 struct padata_priv *padata, int cb_cpu)
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))
125 if ((pinst->flags & PADATA_RESET))
128 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
132 atomic_inc(&pd->refcnt);
134 padata->cb_cpu = cb_cpu;
136 target_cpu = padata_cpu_hash(pd);
137 queue = per_cpu_ptr(pd->pqueue, target_cpu);
139 spin_lock(&queue->parallel.lock);
140 list_add_tail(&padata->list, &queue->parallel.list);
141 spin_unlock(&queue->parallel.lock);
143 queue_work_on(target_cpu, pinst->wq, &queue->work);
146 rcu_read_unlock_bh();
150 EXPORT_SYMBOL(padata_do_parallel);
153 * padata_get_next - Get the next object that needs serialization.
157 * A pointer to the control struct of the next object that needs
158 * serialization, if present in one of the percpu reorder queues.
160 * NULL, if all percpu reorder queues are empty.
162 * -EINPROGRESS, if the next object that needs serialization will
163 * be parallel processed by another cpu and is not yet present in
164 * the cpu's reorder queue.
166 * -ENODATA, if this cpu has to do the parallel processing for
169 static struct padata_priv *padata_get_next(struct parallel_data *pd)
172 unsigned int next_nr, next_index;
173 struct padata_parallel_queue *next_queue;
174 struct padata_priv *padata;
175 struct padata_list *reorder;
177 num_cpus = cpumask_weight(pd->cpumask.pcpu);
180 * Calculate the percpu reorder queue and the sequence
181 * number of the next object.
183 next_nr = pd->processed;
184 next_index = next_nr % num_cpus;
185 cpu = padata_index_to_cpu(pd, next_index);
186 next_queue = per_cpu_ptr(pd->pqueue, cpu);
190 reorder = &next_queue->reorder;
192 spin_lock(&reorder->lock);
193 if (!list_empty(&reorder->list)) {
194 padata = list_entry(reorder->list.next,
195 struct padata_priv, list);
197 list_del_init(&padata->list);
198 atomic_dec(&pd->reorder_objects);
202 spin_unlock(&reorder->lock);
205 spin_unlock(&reorder->lock);
207 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) {
208 padata = ERR_PTR(-ENODATA);
212 padata = ERR_PTR(-EINPROGRESS);
217 static void padata_reorder(struct parallel_data *pd)
220 struct padata_priv *padata;
221 struct padata_serial_queue *squeue;
222 struct padata_instance *pinst = pd->pinst;
225 * We need to ensure that only one cpu can work on dequeueing of
226 * the reorder queue the time. Calculating in which percpu reorder
227 * queue the next object will arrive takes some time. A spinlock
228 * would be highly contended. Also it is not clear in which order
229 * the objects arrive to the reorder queues. So a cpu could wait to
230 * get the lock just to notice that there is nothing to do at the
231 * moment. Therefore we use a trylock and let the holder of the lock
232 * care for all the objects enqueued during the holdtime of the lock.
234 if (!spin_trylock_bh(&pd->lock))
238 padata = padata_get_next(pd);
241 * All reorder queues are empty, or the next object that needs
242 * serialization is parallel processed by another cpu and is
243 * still on it's way to the cpu's reorder queue, nothing to
246 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
250 * This cpu has to do the parallel processing of the next
251 * object. It's waiting in the cpu's parallelization queue,
252 * so exit immediately.
254 if (PTR_ERR(padata) == -ENODATA) {
255 del_timer(&pd->timer);
256 spin_unlock_bh(&pd->lock);
260 cb_cpu = padata->cb_cpu;
261 squeue = per_cpu_ptr(pd->squeue, cb_cpu);
263 spin_lock(&squeue->serial.lock);
264 list_add_tail(&padata->list, &squeue->serial.list);
265 spin_unlock(&squeue->serial.lock);
267 queue_work_on(cb_cpu, pinst->wq, &squeue->work);
270 spin_unlock_bh(&pd->lock);
273 * The next object that needs serialization might have arrived to
274 * the reorder queues in the meantime, we will be called again
275 * from the timer function if no one else cares for it.
277 * Ensure reorder_objects is read after pd->lock is dropped so we see
278 * an increment from another task in padata_do_serial. Pairs with
279 * smp_mb__after_atomic in padata_do_serial.
282 if (atomic_read(&pd->reorder_objects)
283 && !(pinst->flags & PADATA_RESET))
284 mod_timer(&pd->timer, jiffies + HZ);
286 del_timer(&pd->timer);
291 static void padata_reorder_timer(unsigned long arg)
293 struct parallel_data *pd = (struct parallel_data *)arg;
298 static void padata_serial_worker(struct work_struct *serial_work)
300 struct padata_serial_queue *squeue;
301 struct parallel_data *pd;
302 LIST_HEAD(local_list);
305 squeue = container_of(serial_work, struct padata_serial_queue, work);
308 spin_lock(&squeue->serial.lock);
309 list_replace_init(&squeue->serial.list, &local_list);
310 spin_unlock(&squeue->serial.lock);
312 while (!list_empty(&local_list)) {
313 struct padata_priv *padata;
315 padata = list_entry(local_list.next,
316 struct padata_priv, list);
318 list_del_init(&padata->list);
320 padata->serial(padata);
321 atomic_dec(&pd->refcnt);
327 * padata_do_serial - padata serialization function
329 * @padata: object to be serialized.
331 * padata_do_serial must be called for every parallelized object.
332 * The serialization callback function will run with BHs off.
334 void padata_do_serial(struct padata_priv *padata)
337 struct padata_parallel_queue *pqueue;
338 struct parallel_data *pd;
343 pqueue = per_cpu_ptr(pd->pqueue, cpu);
345 spin_lock(&pqueue->reorder.lock);
346 atomic_inc(&pd->reorder_objects);
347 list_add_tail(&padata->list, &pqueue->reorder.list);
348 spin_unlock(&pqueue->reorder.lock);
351 * Ensure the atomic_inc of reorder_objects above is ordered correctly
352 * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
355 smp_mb__after_atomic();
361 EXPORT_SYMBOL(padata_do_serial);
363 static int padata_setup_cpumasks(struct parallel_data *pd,
364 const struct cpumask *pcpumask,
365 const struct cpumask *cbcpumask)
367 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
370 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
371 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
372 free_cpumask_var(pd->cpumask.pcpu);
376 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
380 static void __padata_list_init(struct padata_list *pd_list)
382 INIT_LIST_HEAD(&pd_list->list);
383 spin_lock_init(&pd_list->lock);
386 /* Initialize all percpu queues used by serial workers */
387 static void padata_init_squeues(struct parallel_data *pd)
390 struct padata_serial_queue *squeue;
392 for_each_cpu(cpu, pd->cpumask.cbcpu) {
393 squeue = per_cpu_ptr(pd->squeue, cpu);
395 __padata_list_init(&squeue->serial);
396 INIT_WORK(&squeue->work, padata_serial_worker);
400 /* Initialize all percpu queues used by parallel workers */
401 static void padata_init_pqueues(struct parallel_data *pd)
404 struct padata_parallel_queue *pqueue;
407 for_each_cpu(cpu, pd->cpumask.pcpu) {
408 pqueue = per_cpu_ptr(pd->pqueue, cpu);
410 pqueue->cpu_index = cpu_index;
413 __padata_list_init(&pqueue->reorder);
414 __padata_list_init(&pqueue->parallel);
415 INIT_WORK(&pqueue->work, padata_parallel_worker);
416 atomic_set(&pqueue->num_obj, 0);
420 /* Allocate and initialize the internal cpumask dependend resources. */
421 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
422 const struct cpumask *pcpumask,
423 const struct cpumask *cbcpumask)
425 struct parallel_data *pd;
427 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
431 pd->pqueue = alloc_percpu(struct padata_parallel_queue);
435 pd->squeue = alloc_percpu(struct padata_serial_queue);
437 goto err_free_pqueue;
438 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
439 goto err_free_squeue;
441 padata_init_pqueues(pd);
442 padata_init_squeues(pd);
443 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
444 atomic_set(&pd->seq_nr, -1);
445 atomic_set(&pd->reorder_objects, 0);
446 atomic_set(&pd->refcnt, 0);
448 spin_lock_init(&pd->lock);
453 free_percpu(pd->squeue);
455 free_percpu(pd->pqueue);
462 static void padata_free_pd(struct parallel_data *pd)
464 free_cpumask_var(pd->cpumask.pcpu);
465 free_cpumask_var(pd->cpumask.cbcpu);
466 free_percpu(pd->pqueue);
467 free_percpu(pd->squeue);
471 /* Flush all objects out of the padata queues. */
472 static void padata_flush_queues(struct parallel_data *pd)
475 struct padata_parallel_queue *pqueue;
476 struct padata_serial_queue *squeue;
478 for_each_cpu(cpu, pd->cpumask.pcpu) {
479 pqueue = per_cpu_ptr(pd->pqueue, cpu);
480 flush_work(&pqueue->work);
483 del_timer_sync(&pd->timer);
485 if (atomic_read(&pd->reorder_objects))
488 for_each_cpu(cpu, pd->cpumask.cbcpu) {
489 squeue = per_cpu_ptr(pd->squeue, cpu);
490 flush_work(&squeue->work);
493 BUG_ON(atomic_read(&pd->refcnt) != 0);
496 static void __padata_start(struct padata_instance *pinst)
498 pinst->flags |= PADATA_INIT;
501 static void __padata_stop(struct padata_instance *pinst)
503 if (!(pinst->flags & PADATA_INIT))
506 pinst->flags &= ~PADATA_INIT;
511 padata_flush_queues(pinst->pd);
515 /* Replace the internal control structure with a new one. */
516 static void padata_replace(struct padata_instance *pinst,
517 struct parallel_data *pd_new)
519 struct parallel_data *pd_old = pinst->pd;
520 int notification_mask = 0;
522 pinst->flags |= PADATA_RESET;
524 rcu_assign_pointer(pinst->pd, pd_new);
528 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
529 notification_mask |= PADATA_CPU_PARALLEL;
530 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
531 notification_mask |= PADATA_CPU_SERIAL;
533 padata_flush_queues(pd_old);
534 padata_free_pd(pd_old);
536 if (notification_mask)
537 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
541 pinst->flags &= ~PADATA_RESET;
545 * padata_register_cpumask_notifier - Registers a notifier that will be called
546 * if either pcpu or cbcpu or both cpumasks change.
548 * @pinst: A poineter to padata instance
549 * @nblock: A pointer to notifier block.
551 int padata_register_cpumask_notifier(struct padata_instance *pinst,
552 struct notifier_block *nblock)
554 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
557 EXPORT_SYMBOL(padata_register_cpumask_notifier);
560 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
561 * registered earlier using padata_register_cpumask_notifier
563 * @pinst: A pointer to data instance.
564 * @nlock: A pointer to notifier block.
566 int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
567 struct notifier_block *nblock)
569 return blocking_notifier_chain_unregister(
570 &pinst->cpumask_change_notifier,
573 EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
576 /* If cpumask contains no active cpu, we mark the instance as invalid. */
577 static bool padata_validate_cpumask(struct padata_instance *pinst,
578 const struct cpumask *cpumask)
580 if (!cpumask_intersects(cpumask, cpu_online_mask)) {
581 pinst->flags |= PADATA_INVALID;
585 pinst->flags &= ~PADATA_INVALID;
589 static int __padata_set_cpumasks(struct padata_instance *pinst,
590 cpumask_var_t pcpumask,
591 cpumask_var_t cbcpumask)
594 struct parallel_data *pd;
596 valid = padata_validate_cpumask(pinst, pcpumask);
598 __padata_stop(pinst);
602 valid = padata_validate_cpumask(pinst, cbcpumask);
604 __padata_stop(pinst);
607 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
611 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
612 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
614 padata_replace(pinst, pd);
617 __padata_start(pinst);
623 * padata_set_cpumasks - Set both parallel and serial cpumasks. The first
624 * one is used by parallel workers and the second one
625 * by the wokers doing serialization.
627 * @pinst: padata instance
628 * @pcpumask: the cpumask to use for parallel workers
629 * @cbcpumask: the cpumsak to use for serial workers
631 int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
632 cpumask_var_t cbcpumask)
636 mutex_lock(&pinst->lock);
639 err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
642 mutex_unlock(&pinst->lock);
647 EXPORT_SYMBOL(padata_set_cpumasks);
650 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
651 * equivalent to @cpumask.
653 * @pinst: padata instance
654 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
655 * to parallel and serial cpumasks respectively.
656 * @cpumask: the cpumask to use
658 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
659 cpumask_var_t cpumask)
661 struct cpumask *serial_mask, *parallel_mask;
664 mutex_lock(&pinst->lock);
667 switch (cpumask_type) {
668 case PADATA_CPU_PARALLEL:
669 serial_mask = pinst->cpumask.cbcpu;
670 parallel_mask = cpumask;
672 case PADATA_CPU_SERIAL:
673 parallel_mask = pinst->cpumask.pcpu;
674 serial_mask = cpumask;
680 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
684 mutex_unlock(&pinst->lock);
688 EXPORT_SYMBOL(padata_set_cpumask);
690 static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
692 struct parallel_data *pd;
694 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
695 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
696 pinst->cpumask.cbcpu);
700 padata_replace(pinst, pd);
702 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
703 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
704 __padata_start(pinst);
711 * padata_add_cpu - add a cpu to one or both(parallel and serial)
714 * @pinst: padata instance
716 * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
717 * The @mask may be any combination of the following flags:
718 * PADATA_CPU_SERIAL - serial cpumask
719 * PADATA_CPU_PARALLEL - parallel cpumask
722 int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask)
726 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
729 mutex_lock(&pinst->lock);
732 if (mask & PADATA_CPU_SERIAL)
733 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu);
734 if (mask & PADATA_CPU_PARALLEL)
735 cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
737 err = __padata_add_cpu(pinst, cpu);
740 mutex_unlock(&pinst->lock);
744 EXPORT_SYMBOL(padata_add_cpu);
746 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
748 struct parallel_data *pd = NULL;
750 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
752 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
753 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
754 __padata_stop(pinst);
756 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
757 pinst->cpumask.cbcpu);
761 padata_replace(pinst, pd);
763 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu);
764 cpumask_clear_cpu(cpu, pd->cpumask.pcpu);
771 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
774 * @pinst: padata instance
775 * @cpu: cpu to remove
776 * @mask: bitmask specifying from which cpumask @cpu should be removed
777 * The @mask may be any combination of the following flags:
778 * PADATA_CPU_SERIAL - serial cpumask
779 * PADATA_CPU_PARALLEL - parallel cpumask
781 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
785 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
788 mutex_lock(&pinst->lock);
791 if (mask & PADATA_CPU_SERIAL)
792 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu);
793 if (mask & PADATA_CPU_PARALLEL)
794 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu);
796 err = __padata_remove_cpu(pinst, cpu);
799 mutex_unlock(&pinst->lock);
803 EXPORT_SYMBOL(padata_remove_cpu);
806 * padata_start - start the parallel processing
808 * @pinst: padata instance to start
810 int padata_start(struct padata_instance *pinst)
814 mutex_lock(&pinst->lock);
816 if (pinst->flags & PADATA_INVALID)
819 __padata_start(pinst);
821 mutex_unlock(&pinst->lock);
825 EXPORT_SYMBOL(padata_start);
828 * padata_stop - stop the parallel processing
830 * @pinst: padata instance to stop
832 void padata_stop(struct padata_instance *pinst)
834 mutex_lock(&pinst->lock);
835 __padata_stop(pinst);
836 mutex_unlock(&pinst->lock);
838 EXPORT_SYMBOL(padata_stop);
840 #ifdef CONFIG_HOTPLUG_CPU
842 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
844 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
845 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
849 static int padata_cpu_callback(struct notifier_block *nfb,
850 unsigned long action, void *hcpu)
853 struct padata_instance *pinst;
854 int cpu = (unsigned long)hcpu;
856 pinst = container_of(nfb, struct padata_instance, cpu_notifier);
860 case CPU_ONLINE_FROZEN:
861 case CPU_DOWN_FAILED:
862 case CPU_DOWN_FAILED_FROZEN:
863 if (!pinst_has_cpu(pinst, cpu))
865 mutex_lock(&pinst->lock);
866 err = __padata_add_cpu(pinst, cpu);
867 mutex_unlock(&pinst->lock);
869 return notifier_from_errno(err);
872 case CPU_DOWN_PREPARE:
873 case CPU_DOWN_PREPARE_FROZEN:
874 case CPU_UP_CANCELED:
875 case CPU_UP_CANCELED_FROZEN:
876 if (!pinst_has_cpu(pinst, cpu))
878 mutex_lock(&pinst->lock);
879 err = __padata_remove_cpu(pinst, cpu);
880 mutex_unlock(&pinst->lock);
882 return notifier_from_errno(err);
890 static void __padata_free(struct padata_instance *pinst)
892 #ifdef CONFIG_HOTPLUG_CPU
893 unregister_hotcpu_notifier(&pinst->cpu_notifier);
897 padata_free_pd(pinst->pd);
898 free_cpumask_var(pinst->cpumask.pcpu);
899 free_cpumask_var(pinst->cpumask.cbcpu);
903 #define kobj2pinst(_kobj) \
904 container_of(_kobj, struct padata_instance, kobj)
905 #define attr2pentry(_attr) \
906 container_of(_attr, struct padata_sysfs_entry, attr)
908 static void padata_sysfs_release(struct kobject *kobj)
910 struct padata_instance *pinst = kobj2pinst(kobj);
911 __padata_free(pinst);
914 struct padata_sysfs_entry {
915 struct attribute attr;
916 ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
917 ssize_t (*store)(struct padata_instance *, struct attribute *,
918 const char *, size_t);
921 static ssize_t show_cpumask(struct padata_instance *pinst,
922 struct attribute *attr, char *buf)
924 struct cpumask *cpumask;
927 mutex_lock(&pinst->lock);
928 if (!strcmp(attr->name, "serial_cpumask"))
929 cpumask = pinst->cpumask.cbcpu;
931 cpumask = pinst->cpumask.pcpu;
933 len = snprintf(buf, PAGE_SIZE, "%*pb\n",
934 nr_cpu_ids, cpumask_bits(cpumask));
935 mutex_unlock(&pinst->lock);
936 return len < PAGE_SIZE ? len : -EINVAL;
939 static ssize_t store_cpumask(struct padata_instance *pinst,
940 struct attribute *attr,
941 const char *buf, size_t count)
943 cpumask_var_t new_cpumask;
947 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
950 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
955 mask_type = !strcmp(attr->name, "serial_cpumask") ?
956 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
957 ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
962 free_cpumask_var(new_cpumask);
966 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \
967 static struct padata_sysfs_entry _name##_attr = \
968 __ATTR(_name, 0644, _show_name, _store_name)
969 #define PADATA_ATTR_RO(_name, _show_name) \
970 static struct padata_sysfs_entry _name##_attr = \
971 __ATTR(_name, 0400, _show_name, NULL)
973 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
974 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
977 * Padata sysfs provides the following objects:
978 * serial_cpumask [RW] - cpumask for serial workers
979 * parallel_cpumask [RW] - cpumask for parallel workers
981 static struct attribute *padata_default_attrs[] = {
982 &serial_cpumask_attr.attr,
983 ¶llel_cpumask_attr.attr,
987 static ssize_t padata_sysfs_show(struct kobject *kobj,
988 struct attribute *attr, char *buf)
990 struct padata_instance *pinst;
991 struct padata_sysfs_entry *pentry;
994 pinst = kobj2pinst(kobj);
995 pentry = attr2pentry(attr);
997 ret = pentry->show(pinst, attr, buf);
1002 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
1003 const char *buf, size_t count)
1005 struct padata_instance *pinst;
1006 struct padata_sysfs_entry *pentry;
1009 pinst = kobj2pinst(kobj);
1010 pentry = attr2pentry(attr);
1012 ret = pentry->store(pinst, attr, buf, count);
1017 static const struct sysfs_ops padata_sysfs_ops = {
1018 .show = padata_sysfs_show,
1019 .store = padata_sysfs_store,
1022 static struct kobj_type padata_attr_type = {
1023 .sysfs_ops = &padata_sysfs_ops,
1024 .default_attrs = padata_default_attrs,
1025 .release = padata_sysfs_release,
1029 * padata_alloc_possible - Allocate and initialize padata instance.
1030 * Use the cpu_possible_mask for serial and
1033 * @wq: workqueue to use for the allocated padata instance
1035 struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1037 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1039 EXPORT_SYMBOL(padata_alloc_possible);
1042 * padata_alloc - allocate and initialize a padata instance and specify
1043 * cpumasks for serial and parallel workers.
1045 * @wq: workqueue to use for the allocated padata instance
1046 * @pcpumask: cpumask that will be used for padata parallelization
1047 * @cbcpumask: cpumask that will be used for padata serialization
1049 struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1050 const struct cpumask *pcpumask,
1051 const struct cpumask *cbcpumask)
1053 struct padata_instance *pinst;
1054 struct parallel_data *pd = NULL;
1056 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1061 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1063 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1064 free_cpumask_var(pinst->cpumask.pcpu);
1067 if (!padata_validate_cpumask(pinst, pcpumask) ||
1068 !padata_validate_cpumask(pinst, cbcpumask))
1069 goto err_free_masks;
1071 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1073 goto err_free_masks;
1075 rcu_assign_pointer(pinst->pd, pd);
1079 cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1080 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1086 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1087 kobject_init(&pinst->kobj, &padata_attr_type);
1088 mutex_init(&pinst->lock);
1090 #ifdef CONFIG_HOTPLUG_CPU
1091 pinst->cpu_notifier.notifier_call = padata_cpu_callback;
1092 pinst->cpu_notifier.priority = 0;
1093 register_hotcpu_notifier(&pinst->cpu_notifier);
1099 free_cpumask_var(pinst->cpumask.pcpu);
1100 free_cpumask_var(pinst->cpumask.cbcpu);
1107 EXPORT_SYMBOL(padata_alloc);
1110 * padata_free - free a padata instance
1112 * @padata_inst: padata instance to free
1114 void padata_free(struct padata_instance *pinst)
1116 kobject_put(&pinst->kobj);
1118 EXPORT_SYMBOL(padata_free);