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-rw-r--r--include/linux/padata.h88
-rw-r--r--init/Kconfig4
-rw-r--r--kernel/Makefile1
-rw-r--r--kernel/padata.c690
4 files changed, 783 insertions, 0 deletions
diff --git a/include/linux/padata.h b/include/linux/padata.h
new file mode 100644
index 000000000000..51611da9c498
--- /dev/null
+++ b/include/linux/padata.h
@@ -0,0 +1,88 @@
1/*
2 * padata.h - header for the padata parallelization interface
3 *
4 * Copyright (C) 2008, 2009 secunet Security Networks AG
5 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21#ifndef PADATA_H
22#define PADATA_H
23
24#include <linux/workqueue.h>
25#include <linux/spinlock.h>
26#include <linux/list.h>
27
28struct padata_priv {
29 struct list_head list;
30 struct parallel_data *pd;
31 int cb_cpu;
32 int seq_nr;
33 int info;
34 void (*parallel)(struct padata_priv *padata);
35 void (*serial)(struct padata_priv *padata);
36};
37
38struct padata_list {
39 struct list_head list;
40 spinlock_t lock;
41};
42
43struct padata_queue {
44 struct padata_list parallel;
45 struct padata_list reorder;
46 struct padata_list serial;
47 struct work_struct pwork;
48 struct work_struct swork;
49 struct parallel_data *pd;
50 atomic_t num_obj;
51 int cpu_index;
52};
53
54struct parallel_data {
55 struct padata_instance *pinst;
56 struct padata_queue *queue;
57 atomic_t seq_nr;
58 atomic_t reorder_objects;
59 atomic_t refcnt;
60 unsigned int max_seq_nr;
61 cpumask_var_t cpumask;
62 spinlock_t lock;
63};
64
65struct padata_instance {
66 struct notifier_block cpu_notifier;
67 struct workqueue_struct *wq;
68 struct parallel_data *pd;
69 cpumask_var_t cpumask;
70 struct mutex lock;
71 u8 flags;
72#define PADATA_INIT 1
73#define PADATA_RESET 2
74};
75
76extern struct padata_instance *padata_alloc(const struct cpumask *cpumask,
77 struct workqueue_struct *wq);
78extern void padata_free(struct padata_instance *pinst);
79extern int padata_do_parallel(struct padata_instance *pinst,
80 struct padata_priv *padata, int cb_cpu);
81extern void padata_do_serial(struct padata_priv *padata);
82extern int padata_set_cpumask(struct padata_instance *pinst,
83 cpumask_var_t cpumask);
84extern int padata_add_cpu(struct padata_instance *pinst, int cpu);
85extern int padata_remove_cpu(struct padata_instance *pinst, int cpu);
86extern void padata_start(struct padata_instance *pinst);
87extern void padata_stop(struct padata_instance *pinst);
88#endif
diff --git a/init/Kconfig b/init/Kconfig
index a23da9f01803..9fd23bcc1709 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1252,4 +1252,8 @@ source "block/Kconfig"
1252config PREEMPT_NOTIFIERS 1252config PREEMPT_NOTIFIERS
1253 bool 1253 bool
1254 1254
1255config PADATA
1256 depends on SMP
1257 bool
1258
1255source "kernel/Kconfig.locks" 1259source "kernel/Kconfig.locks"
diff --git a/kernel/Makefile b/kernel/Makefile
index 864ff75d65f2..6aebdeb2aa34 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_SLOW_WORK_DEBUG) += slow-work-debugfs.o
100obj-$(CONFIG_PERF_EVENTS) += perf_event.o 100obj-$(CONFIG_PERF_EVENTS) += perf_event.o
101obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o 101obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
102obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o 102obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o
103obj-$(CONFIG_PADATA) += padata.o
103 104
104ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y) 105ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
105# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is 106# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
diff --git a/kernel/padata.c b/kernel/padata.c
new file mode 100644
index 000000000000..6f9bcb8313d6
--- /dev/null
+++ b/kernel/padata.c
@@ -0,0 +1,690 @@
1/*
2 * padata.c - generic interface to process data streams in parallel
3 *
4 * Copyright (C) 2008, 2009 secunet Security Networks AG
5 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21#include <linux/module.h>
22#include <linux/cpumask.h>
23#include <linux/err.h>
24#include <linux/cpu.h>
25#include <linux/padata.h>
26#include <linux/mutex.h>
27#include <linux/sched.h>
28#include <linux/rcupdate.h>
29
30#define MAX_SEQ_NR INT_MAX - NR_CPUS
31#define MAX_OBJ_NUM 10000 * NR_CPUS
32
33static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
34{
35 int cpu, target_cpu;
36
37 target_cpu = cpumask_first(pd->cpumask);
38 for (cpu = 0; cpu < cpu_index; cpu++)
39 target_cpu = cpumask_next(target_cpu, pd->cpumask);
40
41 return target_cpu;
42}
43
44static int padata_cpu_hash(struct padata_priv *padata)
45{
46 int cpu_index;
47 struct parallel_data *pd;
48
49 pd = padata->pd;
50
51 /*
52 * Hash the sequence numbers to the cpus by taking
53 * seq_nr mod. number of cpus in use.
54 */
55 cpu_index = padata->seq_nr % cpumask_weight(pd->cpumask);
56
57 return padata_index_to_cpu(pd, cpu_index);
58}
59
60static void padata_parallel_worker(struct work_struct *work)
61{
62 struct padata_queue *queue;
63 struct parallel_data *pd;
64 struct padata_instance *pinst;
65 LIST_HEAD(local_list);
66
67 local_bh_disable();
68 queue = container_of(work, struct padata_queue, pwork);
69 pd = queue->pd;
70 pinst = pd->pinst;
71
72 spin_lock(&queue->parallel.lock);
73 list_replace_init(&queue->parallel.list, &local_list);
74 spin_unlock(&queue->parallel.lock);
75
76 while (!list_empty(&local_list)) {
77 struct padata_priv *padata;
78
79 padata = list_entry(local_list.next,
80 struct padata_priv, list);
81
82 list_del_init(&padata->list);
83
84 padata->parallel(padata);
85 }
86
87 local_bh_enable();
88}
89
90/*
91 * padata_do_parallel - padata parallelization function
92 *
93 * @pinst: padata instance
94 * @padata: object to be parallelized
95 * @cb_cpu: cpu the serialization callback function will run on,
96 * must be in the cpumask of padata.
97 *
98 * The parallelization callback function will run with BHs off.
99 * Note: Every object which is parallelized by padata_do_parallel
100 * must be seen by padata_do_serial.
101 */
102int padata_do_parallel(struct padata_instance *pinst,
103 struct padata_priv *padata, int cb_cpu)
104{
105 int target_cpu, err;
106 struct padata_queue *queue;
107 struct parallel_data *pd;
108
109 rcu_read_lock_bh();
110
111 pd = rcu_dereference(pinst->pd);
112
113 err = 0;
114 if (!(pinst->flags & PADATA_INIT))
115 goto out;
116
117 err = -EBUSY;
118 if ((pinst->flags & PADATA_RESET))
119 goto out;
120
121 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
122 goto out;
123
124 err = -EINVAL;
125 if (!cpumask_test_cpu(cb_cpu, pd->cpumask))
126 goto out;
127
128 err = -EINPROGRESS;
129 atomic_inc(&pd->refcnt);
130 padata->pd = pd;
131 padata->cb_cpu = cb_cpu;
132
133 if (unlikely(atomic_read(&pd->seq_nr) == pd->max_seq_nr))
134 atomic_set(&pd->seq_nr, -1);
135
136 padata->seq_nr = atomic_inc_return(&pd->seq_nr);
137
138 target_cpu = padata_cpu_hash(padata);
139 queue = per_cpu_ptr(pd->queue, target_cpu);
140
141 spin_lock(&queue->parallel.lock);
142 list_add_tail(&padata->list, &queue->parallel.list);
143 spin_unlock(&queue->parallel.lock);
144
145 queue_work_on(target_cpu, pinst->wq, &queue->pwork);
146
147out:
148 rcu_read_unlock_bh();
149
150 return err;
151}
152EXPORT_SYMBOL(padata_do_parallel);
153
154static struct padata_priv *padata_get_next(struct parallel_data *pd)
155{
156 int cpu, num_cpus, empty, calc_seq_nr;
157 int seq_nr, next_nr, overrun, next_overrun;
158 struct padata_queue *queue, *next_queue;
159 struct padata_priv *padata;
160 struct padata_list *reorder;
161
162 empty = 0;
163 next_nr = -1;
164 next_overrun = 0;
165 next_queue = NULL;
166
167 num_cpus = cpumask_weight(pd->cpumask);
168
169 for_each_cpu(cpu, pd->cpumask) {
170 queue = per_cpu_ptr(pd->queue, cpu);
171 reorder = &queue->reorder;
172
173 /*
174 * Calculate the seq_nr of the object that should be
175 * next in this queue.
176 */
177 overrun = 0;
178 calc_seq_nr = (atomic_read(&queue->num_obj) * num_cpus)
179 + queue->cpu_index;
180
181 if (unlikely(calc_seq_nr > pd->max_seq_nr)) {
182 calc_seq_nr = calc_seq_nr - pd->max_seq_nr - 1;
183 overrun = 1;
184 }
185
186 if (!list_empty(&reorder->list)) {
187 padata = list_entry(reorder->list.next,
188 struct padata_priv, list);
189
190 seq_nr = padata->seq_nr;
191 BUG_ON(calc_seq_nr != seq_nr);
192 } else {
193 seq_nr = calc_seq_nr;
194 empty++;
195 }
196
197 if (next_nr < 0 || seq_nr < next_nr
198 || (next_overrun && !overrun)) {
199 next_nr = seq_nr;
200 next_overrun = overrun;
201 next_queue = queue;
202 }
203 }
204
205 padata = NULL;
206
207 if (empty == num_cpus)
208 goto out;
209
210 reorder = &next_queue->reorder;
211
212 if (!list_empty(&reorder->list)) {
213 padata = list_entry(reorder->list.next,
214 struct padata_priv, list);
215
216 if (unlikely(next_overrun)) {
217 for_each_cpu(cpu, pd->cpumask) {
218 queue = per_cpu_ptr(pd->queue, cpu);
219 atomic_set(&queue->num_obj, 0);
220 }
221 }
222
223 spin_lock(&reorder->lock);
224 list_del_init(&padata->list);
225 atomic_dec(&pd->reorder_objects);
226 spin_unlock(&reorder->lock);
227
228 atomic_inc(&next_queue->num_obj);
229
230 goto out;
231 }
232
233 if (next_nr % num_cpus == next_queue->cpu_index) {
234 padata = ERR_PTR(-ENODATA);
235 goto out;
236 }
237
238 padata = ERR_PTR(-EINPROGRESS);
239out:
240 return padata;
241}
242
243static void padata_reorder(struct parallel_data *pd)
244{
245 struct padata_priv *padata;
246 struct padata_queue *queue;
247 struct padata_instance *pinst = pd->pinst;
248
249try_again:
250 if (!spin_trylock_bh(&pd->lock))
251 goto out;
252
253 while (1) {
254 padata = padata_get_next(pd);
255
256 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
257 break;
258
259 if (PTR_ERR(padata) == -ENODATA) {
260 spin_unlock_bh(&pd->lock);
261 goto out;
262 }
263
264 queue = per_cpu_ptr(pd->queue, padata->cb_cpu);
265
266 spin_lock(&queue->serial.lock);
267 list_add_tail(&padata->list, &queue->serial.list);
268 spin_unlock(&queue->serial.lock);
269
270 queue_work_on(padata->cb_cpu, pinst->wq, &queue->swork);
271 }
272
273 spin_unlock_bh(&pd->lock);
274
275 if (atomic_read(&pd->reorder_objects))
276 goto try_again;
277
278out:
279 return;
280}
281
282static void padata_serial_worker(struct work_struct *work)
283{
284 struct padata_queue *queue;
285 struct parallel_data *pd;
286 LIST_HEAD(local_list);
287
288 local_bh_disable();
289 queue = container_of(work, struct padata_queue, swork);
290 pd = queue->pd;
291
292 spin_lock(&queue->serial.lock);
293 list_replace_init(&queue->serial.list, &local_list);
294 spin_unlock(&queue->serial.lock);
295
296 while (!list_empty(&local_list)) {
297 struct padata_priv *padata;
298
299 padata = list_entry(local_list.next,
300 struct padata_priv, list);
301
302 list_del_init(&padata->list);
303
304 padata->serial(padata);
305 atomic_dec(&pd->refcnt);
306 }
307 local_bh_enable();
308}
309
310/*
311 * padata_do_serial - padata serialization function
312 *
313 * @padata: object to be serialized.
314 *
315 * padata_do_serial must be called for every parallelized object.
316 * The serialization callback function will run with BHs off.
317 */
318void padata_do_serial(struct padata_priv *padata)
319{
320 int cpu;
321 struct padata_queue *queue;
322 struct parallel_data *pd;
323
324 pd = padata->pd;
325
326 cpu = get_cpu();
327 queue = per_cpu_ptr(pd->queue, cpu);
328
329 spin_lock(&queue->reorder.lock);
330 atomic_inc(&pd->reorder_objects);
331 list_add_tail(&padata->list, &queue->reorder.list);
332 spin_unlock(&queue->reorder.lock);
333
334 put_cpu();
335
336 padata_reorder(pd);
337}
338EXPORT_SYMBOL(padata_do_serial);
339
340static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
341 const struct cpumask *cpumask)
342{
343 int cpu, cpu_index, num_cpus;
344 struct padata_queue *queue;
345 struct parallel_data *pd;
346
347 cpu_index = 0;
348
349 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
350 if (!pd)
351 goto err;
352
353 pd->queue = alloc_percpu(struct padata_queue);
354 if (!pd->queue)
355 goto err_free_pd;
356
357 if (!alloc_cpumask_var(&pd->cpumask, GFP_KERNEL))
358 goto err_free_queue;
359
360 for_each_possible_cpu(cpu) {
361 queue = per_cpu_ptr(pd->queue, cpu);
362
363 queue->pd = pd;
364
365 if (cpumask_test_cpu(cpu, cpumask)
366 && cpumask_test_cpu(cpu, cpu_active_mask)) {
367 queue->cpu_index = cpu_index;
368 cpu_index++;
369 } else
370 queue->cpu_index = -1;
371
372 INIT_LIST_HEAD(&queue->reorder.list);
373 INIT_LIST_HEAD(&queue->parallel.list);
374 INIT_LIST_HEAD(&queue->serial.list);
375 spin_lock_init(&queue->reorder.lock);
376 spin_lock_init(&queue->parallel.lock);
377 spin_lock_init(&queue->serial.lock);
378
379 INIT_WORK(&queue->pwork, padata_parallel_worker);
380 INIT_WORK(&queue->swork, padata_serial_worker);
381 atomic_set(&queue->num_obj, 0);
382 }
383
384 cpumask_and(pd->cpumask, cpumask, cpu_active_mask);
385
386 num_cpus = cpumask_weight(pd->cpumask);
387 pd->max_seq_nr = (MAX_SEQ_NR / num_cpus) * num_cpus - 1;
388
389 atomic_set(&pd->seq_nr, -1);
390 atomic_set(&pd->reorder_objects, 0);
391 atomic_set(&pd->refcnt, 0);
392 pd->pinst = pinst;
393 spin_lock_init(&pd->lock);
394
395 return pd;
396
397err_free_queue:
398 free_percpu(pd->queue);
399err_free_pd:
400 kfree(pd);
401err:
402 return NULL;
403}
404
405static void padata_free_pd(struct parallel_data *pd)
406{
407 free_cpumask_var(pd->cpumask);
408 free_percpu(pd->queue);
409 kfree(pd);
410}
411
412static void padata_replace(struct padata_instance *pinst,
413 struct parallel_data *pd_new)
414{
415 struct parallel_data *pd_old = pinst->pd;
416
417 pinst->flags |= PADATA_RESET;
418
419 rcu_assign_pointer(pinst->pd, pd_new);
420
421 synchronize_rcu();
422
423 while (atomic_read(&pd_old->refcnt) != 0)
424 yield();
425
426 flush_workqueue(pinst->wq);
427
428 padata_free_pd(pd_old);
429
430 pinst->flags &= ~PADATA_RESET;
431}
432
433/*
434 * padata_set_cpumask - set the cpumask that padata should use
435 *
436 * @pinst: padata instance
437 * @cpumask: the cpumask to use
438 */
439int padata_set_cpumask(struct padata_instance *pinst,
440 cpumask_var_t cpumask)
441{
442 struct parallel_data *pd;
443 int err = 0;
444
445 might_sleep();
446
447 mutex_lock(&pinst->lock);
448
449 pd = padata_alloc_pd(pinst, cpumask);
450 if (!pd) {
451 err = -ENOMEM;
452 goto out;
453 }
454
455 cpumask_copy(pinst->cpumask, cpumask);
456
457 padata_replace(pinst, pd);
458
459out:
460 mutex_unlock(&pinst->lock);
461
462 return err;
463}
464EXPORT_SYMBOL(padata_set_cpumask);
465
466static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
467{
468 struct parallel_data *pd;
469
470 if (cpumask_test_cpu(cpu, cpu_active_mask)) {
471 pd = padata_alloc_pd(pinst, pinst->cpumask);
472 if (!pd)
473 return -ENOMEM;
474
475 padata_replace(pinst, pd);
476 }
477
478 return 0;
479}
480
481/*
482 * padata_add_cpu - add a cpu to the padata cpumask
483 *
484 * @pinst: padata instance
485 * @cpu: cpu to add
486 */
487int padata_add_cpu(struct padata_instance *pinst, int cpu)
488{
489 int err;
490
491 might_sleep();
492
493 mutex_lock(&pinst->lock);
494
495 cpumask_set_cpu(cpu, pinst->cpumask);
496 err = __padata_add_cpu(pinst, cpu);
497
498 mutex_unlock(&pinst->lock);
499
500 return err;
501}
502EXPORT_SYMBOL(padata_add_cpu);
503
504static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
505{
506 struct parallel_data *pd;
507
508 if (cpumask_test_cpu(cpu, cpu_online_mask)) {
509 pd = padata_alloc_pd(pinst, pinst->cpumask);
510 if (!pd)
511 return -ENOMEM;
512
513 padata_replace(pinst, pd);
514 }
515
516 return 0;
517}
518
519/*
520 * padata_remove_cpu - remove a cpu from the padata cpumask
521 *
522 * @pinst: padata instance
523 * @cpu: cpu to remove
524 */
525int padata_remove_cpu(struct padata_instance *pinst, int cpu)
526{
527 int err;
528
529 might_sleep();
530
531 mutex_lock(&pinst->lock);
532
533 cpumask_clear_cpu(cpu, pinst->cpumask);
534 err = __padata_remove_cpu(pinst, cpu);
535
536 mutex_unlock(&pinst->lock);
537
538 return err;
539}
540EXPORT_SYMBOL(padata_remove_cpu);
541
542/*
543 * padata_start - start the parallel processing
544 *
545 * @pinst: padata instance to start
546 */
547void padata_start(struct padata_instance *pinst)
548{
549 might_sleep();
550
551 mutex_lock(&pinst->lock);
552 pinst->flags |= PADATA_INIT;
553 mutex_unlock(&pinst->lock);
554}
555EXPORT_SYMBOL(padata_start);
556
557/*
558 * padata_stop - stop the parallel processing
559 *
560 * @pinst: padata instance to stop
561 */
562void padata_stop(struct padata_instance *pinst)
563{
564 might_sleep();
565
566 mutex_lock(&pinst->lock);
567 pinst->flags &= ~PADATA_INIT;
568 mutex_unlock(&pinst->lock);
569}
570EXPORT_SYMBOL(padata_stop);
571
572static int __cpuinit padata_cpu_callback(struct notifier_block *nfb,
573 unsigned long action, void *hcpu)
574{
575 int err;
576 struct padata_instance *pinst;
577 int cpu = (unsigned long)hcpu;
578
579 pinst = container_of(nfb, struct padata_instance, cpu_notifier);
580
581 switch (action) {
582 case CPU_ONLINE:
583 case CPU_ONLINE_FROZEN:
584 if (!cpumask_test_cpu(cpu, pinst->cpumask))
585 break;
586 mutex_lock(&pinst->lock);
587 err = __padata_add_cpu(pinst, cpu);
588 mutex_unlock(&pinst->lock);
589 if (err)
590 return NOTIFY_BAD;
591 break;
592
593 case CPU_DOWN_PREPARE:
594 case CPU_DOWN_PREPARE_FROZEN:
595 if (!cpumask_test_cpu(cpu, pinst->cpumask))
596 break;
597 mutex_lock(&pinst->lock);
598 err = __padata_remove_cpu(pinst, cpu);
599 mutex_unlock(&pinst->lock);
600 if (err)
601 return NOTIFY_BAD;
602 break;
603
604 case CPU_UP_CANCELED:
605 case CPU_UP_CANCELED_FROZEN:
606 if (!cpumask_test_cpu(cpu, pinst->cpumask))
607 break;
608 mutex_lock(&pinst->lock);
609 __padata_remove_cpu(pinst, cpu);
610 mutex_unlock(&pinst->lock);
611
612 case CPU_DOWN_FAILED:
613 case CPU_DOWN_FAILED_FROZEN:
614 if (!cpumask_test_cpu(cpu, pinst->cpumask))
615 break;
616 mutex_lock(&pinst->lock);
617 __padata_add_cpu(pinst, cpu);
618 mutex_unlock(&pinst->lock);
619 }
620
621 return NOTIFY_OK;
622}
623
624/*
625 * padata_alloc - allocate and initialize a padata instance
626 *
627 * @cpumask: cpumask that padata uses for parallelization
628 * @wq: workqueue to use for the allocated padata instance
629 */
630struct padata_instance *padata_alloc(const struct cpumask *cpumask,
631 struct workqueue_struct *wq)
632{
633 int err;
634 struct padata_instance *pinst;
635 struct parallel_data *pd;
636
637 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
638 if (!pinst)
639 goto err;
640
641 pd = padata_alloc_pd(pinst, cpumask);
642 if (!pd)
643 goto err_free_inst;
644
645 rcu_assign_pointer(pinst->pd, pd);
646
647 pinst->wq = wq;
648
649 cpumask_copy(pinst->cpumask, cpumask);
650
651 pinst->flags = 0;
652
653 pinst->cpu_notifier.notifier_call = padata_cpu_callback;
654 pinst->cpu_notifier.priority = 0;
655 err = register_hotcpu_notifier(&pinst->cpu_notifier);
656 if (err)
657 goto err_free_pd;
658
659 mutex_init(&pinst->lock);
660
661 return pinst;
662
663err_free_pd:
664 padata_free_pd(pd);
665err_free_inst:
666 kfree(pinst);
667err:
668 return NULL;
669}
670EXPORT_SYMBOL(padata_alloc);
671
672/*
673 * padata_free - free a padata instance
674 *
675 * @ padata_inst: padata instance to free
676 */
677void padata_free(struct padata_instance *pinst)
678{
679 padata_stop(pinst);
680
681 synchronize_rcu();
682
683 while (atomic_read(&pinst->pd->refcnt) != 0)
684 yield();
685
686 unregister_hotcpu_notifier(&pinst->cpu_notifier);
687 padata_free_pd(pinst->pd);
688 kfree(pinst);
689}
690EXPORT_SYMBOL(padata_free);