kernel/padata.c

   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/slab.h>
  29 #include <linux/sysfs.h>
  30 #include <linux/rcupdate.h>
  31
  32 #define MAX_SEQ_NR (INT_MAX - NR_CPUS)
  33 #define MAX_OBJ_NUM 1000
  34
  35 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
  36 {
  37         int cpu, target_cpu;
  38
  39         target_cpu = cpumask_first(pd->cpumask.pcpu);
  40         for (cpu = 0; cpu < cpu_index; cpu++)
  41                 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
  42
  43         return target_cpu;
  44 }
  45
  46 static int padata_cpu_hash(struct padata_priv *padata)
  47 {
  48         int cpu_index;
  49         struct parallel_data *pd;
  50
  51         pd =  padata->pd;
  52
  53         /*
  54          * Hash the sequence numbers to the cpus by taking
  55          * seq_nr mod. number of cpus in use.
  56          */
  57         cpu_index =  padata->seq_nr % cpumask_weight(pd->cpumask.pcpu);
  58
  59         return padata_index_to_cpu(pd, cpu_index);
  60 }
  61
  62 static void padata_parallel_worker(struct work_struct *parallel_work)
  63 {
  64         struct padata_parallel_queue *pqueue;
  65         struct parallel_data *pd;
  66         struct padata_instance *pinst;
  67         LIST_HEAD(local_list);
  68
  69         local_bh_disable();
  70         pqueue = container_of(parallel_work,
  71                               struct padata_parallel_queue, work);
  72         pd = pqueue->pd;
  73         pinst = pd->pinst;
  74
  75         spin_lock(&pqueue->parallel.lock);
  76         list_replace_init(&pqueue->parallel.list, &local_list);
  77         spin_unlock(&pqueue->parallel.lock);
  78
  79         while (!list_empty(&local_list)) {
  80                 struct padata_priv *padata;
  81
  82                 padata = list_entry(local_list.next,
  83                                     struct padata_priv, list);
  84
  85                 list_del_init(&padata->list);
  86
  87                 padata->parallel(padata);
  88         }
  89
  90         local_bh_enable();
  91 }
  92
  93 /**
  94  * padata_do_parallel - padata parallelization function
  95  *
  96  * @pinst: padata instance
  97  * @padata: object to be parallelized
  98  * @cb_cpu: cpu the serialization callback function will run on,
  99  *          must be in the serial cpumask of padata(i.e. cpumask.cbcpu).
 100  *
 101  * The parallelization callback function will run with BHs off.
 102  * Note: Every object which is parallelized by padata_do_parallel
 103  * must be seen by padata_do_serial.
 104  */
 105 int padata_do_parallel(struct padata_instance *pinst,
 106                        struct padata_priv *padata, int cb_cpu)
 107 {
 108         int target_cpu, err;
 109         struct padata_parallel_queue *queue;
 110         struct parallel_data *pd;
 111
 112         rcu_read_lock_bh();
 113
 114         pd = rcu_dereference(pinst->pd);
 115
 116         err = -EINVAL;
 117         if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
 118                 goto out;
 119
 120         if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu))
 121                 goto out;
 122
 123         err =  -EBUSY;
 124         if ((pinst->flags & PADATA_RESET))
 125                 goto out;
 126
 127         if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM)
 128                 goto out;
 129
 130         err = 0;
 131         atomic_inc(&pd->refcnt);
 132         padata->pd = pd;
 133         padata->cb_cpu = cb_cpu;
 134
 135         if (unlikely(atomic_read(&pd->seq_nr) == pd->max_seq_nr))
 136                 atomic_set(&pd->seq_nr, -1);
 137
 138         padata->seq_nr = atomic_inc_return(&pd->seq_nr);
 139
 140         target_cpu = padata_cpu_hash(padata);
 141         queue = per_cpu_ptr(pd->pqueue, target_cpu);
 142
 143         spin_lock(&queue->parallel.lock);
 144         list_add_tail(&padata->list, &queue->parallel.list);
 145         spin_unlock(&queue->parallel.lock);
 146
 147         queue_work_on(target_cpu, pinst->wq, &queue->work);
 148
 149 out:
 150         rcu_read_unlock_bh();
 151
 152         return err;
 153 }
 154 EXPORT_SYMBOL(padata_do_parallel);
 155
 156 /*
 157  * padata_get_next - Get the next object that needs serialization.
 158  *
 159  * Return values are:
 160  *
 161  * A pointer to the control struct of the next object that needs
 162  * serialization, if present in one of the percpu reorder queues.
 163  *
 164  * NULL, if all percpu reorder queues are empty.
 165  *
 166  * -EINPROGRESS, if the next object that needs serialization will
 167  *  be parallel processed by another cpu and is not yet present in
 168  *  the cpu's reorder queue.
 169  *
 170  * -ENODATA, if this cpu has to do the parallel processing for
 171  *  the next object.
 172  */
 173 static struct padata_priv *padata_get_next(struct parallel_data *pd)
 174 {
 175         int cpu, num_cpus;
 176         int next_nr, next_index;
 177         struct padata_parallel_queue *queue, *next_queue;
 178         struct padata_priv *padata;
 179         struct padata_list *reorder;
 180
 181         num_cpus = cpumask_weight(pd->cpumask.pcpu);
 182
 183         /*
 184          * Calculate the percpu reorder queue and the sequence
 185          * number of the next object.
 186          */
 187         next_nr = pd->processed;
 188         next_index = next_nr % num_cpus;
 189         cpu = padata_index_to_cpu(pd, next_index);
 190         next_queue = per_cpu_ptr(pd->pqueue, cpu);
 191
 192         if (unlikely(next_nr > pd->max_seq_nr)) {
 193                 next_nr = next_nr - pd->max_seq_nr - 1;
 194                 next_index = next_nr % num_cpus;
 195                 cpu = padata_index_to_cpu(pd, next_index);
 196                 next_queue = per_cpu_ptr(pd->pqueue, cpu);
 197                 pd->processed = 0;
 198         }
 199
 200         padata = NULL;
 201
 202         reorder = &next_queue->reorder;
 203
 204         if (!list_empty(&reorder->list)) {
 205                 padata = list_entry(reorder->list.next,
 206                                     struct padata_priv, list);
 207
 208                 BUG_ON(next_nr != padata->seq_nr);
 209
 210                 spin_lock(&reorder->lock);
 211                 list_del_init(&padata->list);
 212                 atomic_dec(&pd->reorder_objects);
 213                 spin_unlock(&reorder->lock);
 214
 215                 pd->processed++;
 216
 217                 goto out;
 218         }
 219
 220         queue = per_cpu_ptr(pd->pqueue, smp_processor_id());
 221         if (queue->cpu_index == next_queue->cpu_index) {
 222                 padata = ERR_PTR(-ENODATA);
 223                 goto out;
 224         }
 225
 226         padata = ERR_PTR(-EINPROGRESS);
 227 out:
 228         return padata;
 229 }
 230
 231 static void padata_reorder(struct parallel_data *pd)
 232 {
 233         struct padata_priv *padata;
 234         struct padata_serial_queue *squeue;
 235         struct padata_instance *pinst = pd->pinst;
 236
 237         /*
 238          * We need to ensure that only one cpu can work on dequeueing of
 239          * the reorder queue the time. Calculating in which percpu reorder
 240          * queue the next object will arrive takes some time. A spinlock
 241          * would be highly contended. Also it is not clear in which order
 242          * the objects arrive to the reorder queues. So a cpu could wait to
 243          * get the lock just to notice that there is nothing to do at the
 244          * moment. Therefore we use a trylock and let the holder of the lock
 245          * care for all the objects enqueued during the holdtime of the lock.
 246          */
 247         if (!spin_trylock_bh(&pd->lock))
 248                 return;
 249
 250         while (1) {
 251                 padata = padata_get_next(pd);
 252
 253                 /*
 254                  * All reorder queues are empty, or the next object that needs
 255                  * serialization is parallel processed by another cpu and is
 256                  * still on it's way to the cpu's reorder queue, nothing to
 257                  * do for now.
 258                  */
 259                 if (!padata || PTR_ERR(padata) == -EINPROGRESS)
 260                         break;
 261
 262                 /*
 263                  * This cpu has to do the parallel processing of the next
 264                  * object. It's waiting in the cpu's parallelization queue,
 265                  * so exit immediately.
 266                  */
 267                 if (PTR_ERR(padata) == -ENODATA) {
 268                         del_timer(&pd->timer);
 269                         spin_unlock_bh(&pd->lock);
 270                         return;
 271                 }
 272
 273                 squeue = per_cpu_ptr(pd->squeue, padata->cb_cpu);
 274
 275                 spin_lock(&squeue->serial.lock);
 276                 list_add_tail(&padata->list, &squeue->serial.list);
 277                 spin_unlock(&squeue->serial.lock);
 278
 279                 queue_work_on(padata->cb_cpu, pinst->wq, &squeue->work);
 280         }
 281
 282         spin_unlock_bh(&pd->lock);
 283
 284         /*
 285          * The next object that needs serialization might have arrived to
 286          * the reorder queues in the meantime, we will be called again
 287          * from the timer function if no one else cares for it.
 288          */
 289         if (atomic_read(&pd->reorder_objects)
 290                         && !(pinst->flags & PADATA_RESET))
 291                 mod_timer(&pd->timer, jiffies + HZ);
 292         else
 293                 del_timer(&pd->timer);
 294
 295         return;
 296 }
 297
 298 static void padata_reorder_timer(unsigned long arg)
 299 {
 300         struct parallel_data *pd = (struct parallel_data *)arg;
 301
 302         padata_reorder(pd);
 303 }
 304
 305 static void padata_serial_worker(struct work_struct *serial_work)
 306 {
 307         struct padata_serial_queue *squeue;
 308         struct parallel_data *pd;
 309         LIST_HEAD(local_list);
 310
 311         local_bh_disable();
 312         squeue = container_of(serial_work, struct padata_serial_queue, work);
 313         pd = squeue->pd;
 314
 315         spin_lock(&squeue->serial.lock);
 316         list_replace_init(&squeue->serial.list, &local_list);
 317         spin_unlock(&squeue->serial.lock);
 318
 319         while (!list_empty(&local_list)) {
 320                 struct padata_priv *padata;
 321
 322                 padata = list_entry(local_list.next,
 323                                     struct padata_priv, list);
 324
 325                 list_del_init(&padata->list);
 326
 327                 padata->serial(padata);
 328                 atomic_dec(&pd->refcnt);
 329         }
 330         local_bh_enable();
 331 }
 332
 333 /**
 334  * padata_do_serial - padata serialization function
 335  *
 336  * @padata: object to be serialized.
 337  *
 338  * padata_do_serial must be called for every parallelized object.
 339  * The serialization callback function will run with BHs off.
 340  */
 341 void padata_do_serial(struct padata_priv *padata)
 342 {
 343         int cpu;
 344         struct padata_parallel_queue *pqueue;
 345         struct parallel_data *pd;
 346
 347         pd = padata->pd;
 348
 349         cpu = get_cpu();
 350         pqueue = per_cpu_ptr(pd->pqueue, cpu);
 351
 352         spin_lock(&pqueue->reorder.lock);
 353         atomic_inc(&pd->reorder_objects);
 354         list_add_tail(&padata->list, &pqueue->reorder.list);
 355         spin_unlock(&pqueue->reorder.lock);
 356
 357         put_cpu();
 358
 359         padata_reorder(pd);
 360 }
 361 EXPORT_SYMBOL(padata_do_serial);
 362
 363 static int padata_setup_cpumasks(struct parallel_data *pd,
 364                                  const struct cpumask *pcpumask,
 365                                  const struct cpumask *cbcpumask)
 366 {
 367         if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
 368                 return -ENOMEM;
 369
 370         cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_active_mask);
 371         if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
 372                 free_cpumask_var(pd->cpumask.cbcpu);
 373                 return -ENOMEM;
 374         }
 375
 376         cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_active_mask);
 377         return 0;
 378 }
 379
 380 static void __padata_list_init(struct padata_list *pd_list)
 381 {
 382         INIT_LIST_HEAD(&pd_list->list);
 383         spin_lock_init(&pd_list->lock);
 384 }
 385
 386 /* Initialize all percpu queues used by serial workers */
 387 static void padata_init_squeues(struct parallel_data *pd)
 388 {
 389         int cpu;
 390         struct padata_serial_queue *squeue;
 391
 392         for_each_cpu(cpu, pd->cpumask.cbcpu) {
 393                 squeue = per_cpu_ptr(pd->squeue, cpu);
 394                 squeue->pd = pd;
 395                 __padata_list_init(&squeue->serial);
 396                 INIT_WORK(&squeue->work, padata_serial_worker);
 397         }
 398 }
 399
 400 /* Initialize all percpu queues used by parallel workers */
 401 static void padata_init_pqueues(struct parallel_data *pd)
 402 {
 403         int cpu_index, num_cpus, cpu;
 404         struct padata_parallel_queue *pqueue;
 405
 406         cpu_index = 0;
 407         for_each_cpu(cpu, pd->cpumask.pcpu) {
 408                 pqueue = per_cpu_ptr(pd->pqueue, cpu);
 409                 pqueue->pd = pd;
 410                 pqueue->cpu_index = cpu_index;
 411                 cpu_index++;
 412
 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);
 417         }
 418
 419         num_cpus = cpumask_weight(pd->cpumask.pcpu);
 420         pd->max_seq_nr = num_cpus ? (MAX_SEQ_NR / num_cpus) * num_cpus - 1 : 0;
 421 }
 422
 423 /* Allocate and initialize the internal cpumask dependend resources. */
 424 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst,
 425                                              const struct cpumask *pcpumask,
 426                                              const struct cpumask *cbcpumask)
 427 {
 428         struct parallel_data *pd;
 429
 430         pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
 431         if (!pd)
 432                 goto err;
 433
 434         pd->pqueue = alloc_percpu(struct padata_parallel_queue);
 435         if (!pd->pqueue)
 436                 goto err_free_pd;
 437
 438         pd->squeue = alloc_percpu(struct padata_serial_queue);
 439         if (!pd->squeue)
 440                 goto err_free_pqueue;
 441         if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0)
 442                 goto err_free_squeue;
 443
 444         padata_init_pqueues(pd);
 445         padata_init_squeues(pd);
 446         setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd);
 447         atomic_set(&pd->seq_nr, -1);
 448         atomic_set(&pd->reorder_objects, 0);
 449         atomic_set(&pd->refcnt, 0);
 450         pd->pinst = pinst;
 451         spin_lock_init(&pd->lock);
 452
 453         return pd;
 454
 455 err_free_squeue:
 456         free_percpu(pd->squeue);
 457 err_free_pqueue:
 458         free_percpu(pd->pqueue);
 459 err_free_pd:
 460         kfree(pd);
 461 err:
 462         return NULL;
 463 }
 464
 465 static void padata_free_pd(struct parallel_data *pd)
 466 {
 467         free_cpumask_var(pd->cpumask.pcpu);
 468         free_cpumask_var(pd->cpumask.cbcpu);
 469         free_percpu(pd->pqueue);
 470         free_percpu(pd->squeue);
 471         kfree(pd);
 472 }
 473
 474 /* Flush all objects out of the padata queues. */
 475 static void padata_flush_queues(struct parallel_data *pd)
 476 {
 477         int cpu;
 478         struct padata_parallel_queue *pqueue;
 479         struct padata_serial_queue *squeue;
 480
 481         for_each_cpu(cpu, pd->cpumask.pcpu) {
 482                 pqueue = per_cpu_ptr(pd->pqueue, cpu);
 483                 flush_work(&pqueue->work);
 484         }
 485
 486         del_timer_sync(&pd->timer);
 487
 488         if (atomic_read(&pd->reorder_objects))
 489                 padata_reorder(pd);
 490
 491         for_each_cpu(cpu, pd->cpumask.cbcpu) {
 492                 squeue = per_cpu_ptr(pd->squeue, cpu);
 493                 flush_work(&squeue->work);
 494         }
 495
 496         BUG_ON(atomic_read(&pd->refcnt) != 0);
 497 }
 498
 499 static void __padata_start(struct padata_instance *pinst)
 500 {
 501         pinst->flags |= PADATA_INIT;
 502 }
 503
 504 static void __padata_stop(struct padata_instance *pinst)
 505 {
 506         if (!(pinst->flags & PADATA_INIT))
 507                 return;
 508
 509         pinst->flags &= ~PADATA_INIT;
 510
 511         synchronize_rcu();
 512
 513         get_online_cpus();
 514         padata_flush_queues(pinst->pd);
 515         put_online_cpus();
 516 }
 517
 518 /* Replace the internal control structure with a new one. */
 519 static void padata_replace(struct padata_instance *pinst,
 520                            struct parallel_data *pd_new)
 521 {
 522         struct parallel_data *pd_old = pinst->pd;
 523         int notification_mask = 0;
 524
 525         pinst->flags |= PADATA_RESET;
 526
 527         rcu_assign_pointer(pinst->pd, pd_new);
 528
 529         synchronize_rcu();
 530
 531         if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu))
 532                 notification_mask |= PADATA_CPU_PARALLEL;
 533         if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu))
 534                 notification_mask |= PADATA_CPU_SERIAL;
 535
 536         padata_flush_queues(pd_old);
 537         padata_free_pd(pd_old);
 538
 539         if (notification_mask)
 540                 blocking_notifier_call_chain(&pinst->cpumask_change_notifier,
 541                                              notification_mask,
 542                                              &pd_new->cpumask);
 543
 544         pinst->flags &= ~PADATA_RESET;
 545 }
 546
 547 /**
 548  * padata_register_cpumask_notifier - Registers a notifier that will be called
 549  *                             if either pcpu or cbcpu or both cpumasks change.
 550  *
 551  * @pinst: A poineter to padata instance
 552  * @nblock: A pointer to notifier block.
 553  */
 554 int padata_register_cpumask_notifier(struct padata_instance *pinst,
 555                                      struct notifier_block *nblock)
 556 {
 557         return blocking_notifier_chain_register(&pinst->cpumask_change_notifier,
 558                                                 nblock);
 559 }
 560 EXPORT_SYMBOL(padata_register_cpumask_notifier);
 561
 562 /**
 563  * padata_unregister_cpumask_notifier - Unregisters cpumask notifier
 564  *        registered earlier  using padata_register_cpumask_notifier
 565  *
 566  * @pinst: A pointer to data instance.
 567  * @nlock: A pointer to notifier block.
 568  */
 569 int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
 570                                        struct notifier_block *nblock)
 571 {
 572         return blocking_notifier_chain_unregister(
 573                 &pinst->cpumask_change_notifier,
 574                 nblock);
 575 }
 576 EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
 577
 578
 579 /* If cpumask contains no active cpu, we mark the instance as invalid. */
 580 static bool padata_validate_cpumask(struct padata_instance *pinst,
 581                                     const struct cpumask *cpumask)
 582 {
 583         if (!cpumask_intersects(cpumask, cpu_active_mask)) {
 584                 pinst->flags |= PADATA_INVALID;
 585                 return false;
 586         }
 587
 588         pinst->flags &= ~PADATA_INVALID;
 589         return true;
 590 }
 591
 592 static int __padata_set_cpumasks(struct padata_instance *pinst,
 593                                  cpumask_var_t pcpumask,
 594                                  cpumask_var_t cbcpumask)
 595 {
 596         int valid;
 597         struct parallel_data *pd;
 598
 599         valid = padata_validate_cpumask(pinst, pcpumask);
 600         if (!valid) {
 601                 __padata_stop(pinst);
 602                 goto out_replace;
 603         }
 604
 605         valid = padata_validate_cpumask(pinst, cbcpumask);
 606         if (!valid)
 607                 __padata_stop(pinst);
 608
 609 out_replace:
 610         pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
 611         if (!pd)
 612                 return -ENOMEM;
 613
 614         cpumask_copy(pinst->cpumask.pcpu, pcpumask);
 615         cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
 616
 617         padata_replace(pinst, pd);
 618
 619         if (valid)
 620                 __padata_start(pinst);
 621
 622         return 0;
 623 }
 624
 625 /**
 626  * padata_set_cpumasks - Set both parallel and serial cpumasks. The first
 627  *                       one is used by parallel workers and the second one
 628  *                       by the wokers doing serialization.
 629  *
 630  * @pinst: padata instance
 631  * @pcpumask: the cpumask to use for parallel workers
 632  * @cbcpumask: the cpumsak to use for serial workers
 633  */
 634 int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask,
 635                         cpumask_var_t cbcpumask)
 636 {
 637         int err;
 638
 639         mutex_lock(&pinst->lock);
 640         get_online_cpus();
 641
 642         err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask);
 643
 644         put_online_cpus();
 645         mutex_unlock(&pinst->lock);
 646
 647         return err;
 648
 649 }
 650 EXPORT_SYMBOL(padata_set_cpumasks);
 651
 652 /**
 653  * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value
 654  *                     equivalent to @cpumask.
 655  *
 656  * @pinst: padata instance
 657  * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
 658  *                to parallel and serial cpumasks respectively.
 659  * @cpumask: the cpumask to use
 660  */
 661 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
 662                        cpumask_var_t cpumask)
 663 {
 664         struct cpumask *serial_mask, *parallel_mask;
 665         int err = -EINVAL;
 666
 667         mutex_lock(&pinst->lock);
 668         get_online_cpus();
 669
 670         switch (cpumask_type) {
 671         case PADATA_CPU_PARALLEL:
 672                 serial_mask = pinst->cpumask.cbcpu;
 673                 parallel_mask = cpumask;
 674                 break;
 675         case PADATA_CPU_SERIAL:
 676                 parallel_mask = pinst->cpumask.pcpu;
 677                 serial_mask = cpumask;
 678                 break;
 679         default:
 680                  goto out;
 681         }
 682
 683         err =  __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
 684
 685 out:
 686         put_online_cpus();
 687         mutex_unlock(&pinst->lock);
 688
 689         return err;
 690 }
 691 EXPORT_SYMBOL(padata_set_cpumask);
 692
 693 static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
 694 {
 695         struct parallel_data *pd;
 696
 697         if (cpumask_test_cpu(cpu, cpu_active_mask)) {
 698                 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
 699                                      pinst->cpumask.cbcpu);
 700                 if (!pd)
 701                         return -ENOMEM;
 702
 703                 padata_replace(pinst, pd);
 704
 705                 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
 706                     padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
 707                         __padata_start(pinst);
 708         }
 709
 710         return 0;
 711 }
 712
 713  /**
 714  * padata_add_cpu - add a cpu to one or both(parallel and serial)
 715  *                  padata cpumasks.
 716  *
 717  * @pinst: padata instance
 718  * @cpu: cpu to add
 719  * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added.
 720  *        The @mask may be any combination of the following flags:
 721  *          PADATA_CPU_SERIAL   - serial cpumask
 722  *          PADATA_CPU_PARALLEL - parallel cpumask
 723  */
 724
 725 int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask)
 726 {
 727         int err;
 728
 729         if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
 730                 return -EINVAL;
 731
 732         mutex_lock(&pinst->lock);
 733
 734         get_online_cpus();
 735         if (mask & PADATA_CPU_SERIAL)
 736                 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu);
 737         if (mask & PADATA_CPU_PARALLEL)
 738                 cpumask_set_cpu(cpu, pinst->cpumask.pcpu);
 739
 740         err = __padata_add_cpu(pinst, cpu);
 741         put_online_cpus();
 742
 743         mutex_unlock(&pinst->lock);
 744
 745         return err;
 746 }
 747 EXPORT_SYMBOL(padata_add_cpu);
 748
 749 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
 750 {
 751         struct parallel_data *pd = NULL;
 752
 753         if (cpumask_test_cpu(cpu, cpu_online_mask)) {
 754
 755                 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
 756                     !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
 757                         __padata_stop(pinst);
 758
 759                 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
 760                                      pinst->cpumask.cbcpu);
 761                 if (!pd)
 762                         return -ENOMEM;
 763
 764                 padata_replace(pinst, pd);
 765         }
 766
 767         return 0;
 768 }
 769
 770  /**
 771  * padata_remove_cpu - remove a cpu from the one or both(serial and parallel)
 772  *                     padata cpumasks.
 773  *
 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
 780  */
 781 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask)
 782 {
 783         int err;
 784
 785         if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL)))
 786                 return -EINVAL;
 787
 788         mutex_lock(&pinst->lock);
 789
 790         get_online_cpus();
 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);
 795
 796         err = __padata_remove_cpu(pinst, cpu);
 797         put_online_cpus();
 798
 799         mutex_unlock(&pinst->lock);
 800
 801         return err;
 802 }
 803 EXPORT_SYMBOL(padata_remove_cpu);
 804
 805 /**
 806  * padata_start - start the parallel processing
 807  *
 808  * @pinst: padata instance to start
 809  */
 810 int padata_start(struct padata_instance *pinst)
 811 {
 812         int err = 0;
 813
 814         mutex_lock(&pinst->lock);
 815
 816         if (pinst->flags & PADATA_INVALID)
 817                 err =-EINVAL;
 818
 819          __padata_start(pinst);
 820
 821         mutex_unlock(&pinst->lock);
 822
 823         return err;
 824 }
 825 EXPORT_SYMBOL(padata_start);
 826
 827 /**
 828  * padata_stop - stop the parallel processing
 829  *
 830  * @pinst: padata instance to stop
 831  */
 832 void padata_stop(struct padata_instance *pinst)
 833 {
 834         mutex_lock(&pinst->lock);
 835         __padata_stop(pinst);
 836         mutex_unlock(&pinst->lock);
 837 }
 838 EXPORT_SYMBOL(padata_stop);
 839
 840 #ifdef CONFIG_HOTPLUG_CPU
 841
 842 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
 843 {
 844         return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
 845                 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
 846 }
 847
 848
 849 static int padata_cpu_callback(struct notifier_block *nfb,
 850                                unsigned long action, void *hcpu)
 851 {
 852         int err;
 853         struct padata_instance *pinst;
 854         int cpu = (unsigned long)hcpu;
 855
 856         pinst = container_of(nfb, struct padata_instance, cpu_notifier);
 857
 858         switch (action) {
 859         case CPU_ONLINE:
 860         case CPU_ONLINE_FROZEN:
 861                 if (!pinst_has_cpu(pinst, cpu))
 862                         break;
 863                 mutex_lock(&pinst->lock);
 864                 err = __padata_add_cpu(pinst, cpu);
 865                 mutex_unlock(&pinst->lock);
 866                 if (err)
 867                         return notifier_from_errno(err);
 868                 break;
 869
 870         case CPU_DOWN_PREPARE:
 871         case CPU_DOWN_PREPARE_FROZEN:
 872                 if (!pinst_has_cpu(pinst, cpu))
 873                         break;
 874                 mutex_lock(&pinst->lock);
 875                 err = __padata_remove_cpu(pinst, cpu);
 876                 mutex_unlock(&pinst->lock);
 877                 if (err)
 878                         return notifier_from_errno(err);
 879                 break;
 880
 881         case CPU_UP_CANCELED:
 882         case CPU_UP_CANCELED_FROZEN:
 883                 if (!pinst_has_cpu(pinst, cpu))
 884                         break;
 885                 mutex_lock(&pinst->lock);
 886                 __padata_remove_cpu(pinst, cpu);
 887                 mutex_unlock(&pinst->lock);
 888
 889         case CPU_DOWN_FAILED:
 890         case CPU_DOWN_FAILED_FROZEN:
 891                 if (!pinst_has_cpu(pinst, cpu))
 892                         break;
 893                 mutex_lock(&pinst->lock);
 894                 __padata_add_cpu(pinst, cpu);
 895                 mutex_unlock(&pinst->lock);
 896         }
 897
 898         return NOTIFY_OK;
 899 }
 900 #endif
 901
 902 static void __padata_free(struct padata_instance *pinst)
 903 {
 904 #ifdef CONFIG_HOTPLUG_CPU
 905         unregister_hotcpu_notifier(&pinst->cpu_notifier);
 906 #endif
 907
 908         padata_stop(pinst);
 909         padata_free_pd(pinst->pd);
 910         free_cpumask_var(pinst->cpumask.pcpu);
 911         free_cpumask_var(pinst->cpumask.cbcpu);
 912         kfree(pinst);
 913 }
 914
 915 #define kobj2pinst(_kobj)                                       \
 916         container_of(_kobj, struct padata_instance, kobj)
 917 #define attr2pentry(_attr)                                      \
 918         container_of(_attr, struct padata_sysfs_entry, attr)
 919
 920 static void padata_sysfs_release(struct kobject *kobj)
 921 {
 922         struct padata_instance *pinst = kobj2pinst(kobj);
 923         __padata_free(pinst);
 924 }
 925
 926 struct padata_sysfs_entry {
 927         struct attribute attr;
 928         ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
 929         ssize_t (*store)(struct padata_instance *, struct attribute *,
 930                          const char *, size_t);
 931 };
 932
 933 static ssize_t show_cpumask(struct padata_instance *pinst,
 934                             struct attribute *attr,  char *buf)
 935 {
 936         struct cpumask *cpumask;
 937         ssize_t len;
 938
 939         mutex_lock(&pinst->lock);
 940         if (!strcmp(attr->name, "serial_cpumask"))
 941                 cpumask = pinst->cpumask.cbcpu;
 942         else
 943                 cpumask = pinst->cpumask.pcpu;
 944
 945         len = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask),
 946                                nr_cpu_ids);
 947         if (PAGE_SIZE - len < 2)
 948                 len = -EINVAL;
 949         else
 950                 len += sprintf(buf + len, "\n");
 951
 952         mutex_unlock(&pinst->lock);
 953         return len;
 954 }
 955
 956 static ssize_t store_cpumask(struct padata_instance *pinst,
 957                              struct attribute *attr,
 958                              const char *buf, size_t count)
 959 {
 960         cpumask_var_t new_cpumask;
 961         ssize_t ret;
 962         int mask_type;
 963
 964         if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
 965                 return -ENOMEM;
 966
 967         ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
 968                            nr_cpumask_bits);
 969         if (ret < 0)
 970                 goto out;
 971
 972         mask_type = !strcmp(attr->name, "serial_cpumask") ?
 973                 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
 974         ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
 975         if (!ret)
 976                 ret = count;
 977
 978 out:
 979         free_cpumask_var(new_cpumask);
 980         return ret;
 981 }
 982
 983 #define PADATA_ATTR_RW(_name, _show_name, _store_name)          \
 984         static struct padata_sysfs_entry _name##_attr =         \
 985                 __ATTR(_name, 0644, _show_name, _store_name)
 986 #define PADATA_ATTR_RO(_name, _show_name)               \
 987         static struct padata_sysfs_entry _name##_attr = \
 988                 __ATTR(_name, 0400, _show_name, NULL)
 989
 990 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
 991 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
 992
 993 /*
 994  * Padata sysfs provides the following objects:
 995  * serial_cpumask   [RW] - cpumask for serial workers
 996  * parallel_cpumask [RW] - cpumask for parallel workers
 997  */
 998 static struct attribute *padata_default_attrs[] = {
 999         &serial_cpumask_attr.attr,
1000         &parallel_cpumask_attr.attr,
1001         NULL,
1002 };
1003
1004 static ssize_t padata_sysfs_show(struct kobject *kobj,
1005                                  struct attribute *attr, char *buf)
1006 {
1007         struct padata_instance *pinst;
1008         struct padata_sysfs_entry *pentry;
1009         ssize_t ret = -EIO;
1010
1011         pinst = kobj2pinst(kobj);
1012         pentry = attr2pentry(attr);
1013         if (pentry->show)
1014                 ret = pentry->show(pinst, attr, buf);
1015
1016         return ret;
1017 }
1018
1019 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
1020                                   const char *buf, size_t count)
1021 {
1022         struct padata_instance *pinst;
1023         struct padata_sysfs_entry *pentry;
1024         ssize_t ret = -EIO;
1025
1026         pinst = kobj2pinst(kobj);
1027         pentry = attr2pentry(attr);
1028         if (pentry->show)
1029                 ret = pentry->store(pinst, attr, buf, count);
1030
1031         return ret;
1032 }
1033
1034 static const struct sysfs_ops padata_sysfs_ops = {
1035         .show = padata_sysfs_show,
1036         .store = padata_sysfs_store,
1037 };
1038
1039 static struct kobj_type padata_attr_type = {
1040         .sysfs_ops = &padata_sysfs_ops,
1041         .default_attrs = padata_default_attrs,
1042         .release = padata_sysfs_release,
1043 };
1044
1045 /**
1046  * padata_alloc_possible - Allocate and initialize padata instance.
1047  *                         Use the cpu_possible_mask for serial and
1048  *                         parallel workers.
1049  *
1050  * @wq: workqueue to use for the allocated padata instance
1051  */
1052 struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq)
1053 {
1054         return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask);
1055 }
1056 EXPORT_SYMBOL(padata_alloc_possible);
1057
1058 /**
1059  * padata_alloc - allocate and initialize a padata instance and specify
1060  *                cpumasks for serial and parallel workers.
1061  *
1062  * @wq: workqueue to use for the allocated padata instance
1063  * @pcpumask: cpumask that will be used for padata parallelization
1064  * @cbcpumask: cpumask that will be used for padata serialization
1065  */
1066 struct padata_instance *padata_alloc(struct workqueue_struct *wq,
1067                                      const struct cpumask *pcpumask,
1068                                      const struct cpumask *cbcpumask)
1069 {
1070         struct padata_instance *pinst;
1071         struct parallel_data *pd = NULL;
1072
1073         pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
1074         if (!pinst)
1075                 goto err;
1076
1077         get_online_cpus();
1078         if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
1079                 goto err_free_inst;
1080         if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
1081                 free_cpumask_var(pinst->cpumask.pcpu);
1082                 goto err_free_inst;
1083         }
1084         if (!padata_validate_cpumask(pinst, pcpumask) ||
1085             !padata_validate_cpumask(pinst, cbcpumask))
1086                 goto err_free_masks;
1087
1088         pd = padata_alloc_pd(pinst, pcpumask, cbcpumask);
1089         if (!pd)
1090                 goto err_free_masks;
1091
1092         rcu_assign_pointer(pinst->pd, pd);
1093
1094         pinst->wq = wq;
1095
1096         cpumask_copy(pinst->cpumask.pcpu, pcpumask);
1097         cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
1098
1099         pinst->flags = 0;
1100
1101 #ifdef CONFIG_HOTPLUG_CPU
1102         pinst->cpu_notifier.notifier_call = padata_cpu_callback;
1103         pinst->cpu_notifier.priority = 0;
1104         register_hotcpu_notifier(&pinst->cpu_notifier);
1105 #endif
1106
1107         put_online_cpus();
1108
1109         BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier);
1110         kobject_init(&pinst->kobj, &padata_attr_type);
1111         mutex_init(&pinst->lock);
1112
1113         return pinst;
1114
1115 err_free_masks:
1116         free_cpumask_var(pinst->cpumask.pcpu);
1117         free_cpumask_var(pinst->cpumask.cbcpu);
1118 err_free_inst:
1119         kfree(pinst);
1120         put_online_cpus();
1121 err:
1122         return NULL;
1123 }
1124 EXPORT_SYMBOL(padata_alloc);
1125
1126 /**
1127  * padata_free - free a padata instance
1128  *
1129  * @padata_inst: padata instance to free
1130  */
1131 void padata_free(struct padata_instance *pinst)
1132 {
1133         kobject_put(&pinst->kobj);
1134 }
1135 EXPORT_SYMBOL(padata_free);