1 /* 2 * padata.c - generic interface to process data streams in parallel 3 * 4 * See Documentation/padata.txt for an api documentation. 5 * 6 * Copyright (C) 2008, 2009 secunet Security Networks AG 7 * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com> 8 * 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. 12 * 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 16 * more details. 17 * 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. 21 */ 22 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> 33 34 #define MAX_OBJ_NUM 1000 35 36 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index) 37 { 38 int cpu, target_cpu; 39 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); 43 44 return target_cpu; 45 } 46 47 static int padata_cpu_hash(struct parallel_data *pd) 48 { 49 int cpu_index; 50 51 /* 52 * Hash the sequence numbers to the cpus by taking 53 * seq_nr mod. number of cpus in use. 54 */ 55 56 spin_lock(&pd->seq_lock); 57 cpu_index = pd->seq_nr % cpumask_weight(pd->cpumask.pcpu); 58 pd->seq_nr++; 59 spin_unlock(&pd->seq_lock); 60 61 return padata_index_to_cpu(pd, cpu_index); 62 } 63 64 static void padata_parallel_worker(struct work_struct *parallel_work) 65 { 66 struct padata_parallel_queue *pqueue; 67 struct parallel_data *pd; 68 struct padata_instance *pinst; 69 LIST_HEAD(local_list); 70 71 local_bh_disable(); 72 pqueue = container_of(parallel_work, 73 struct padata_parallel_queue, work); 74 pd = pqueue->pd; 75 pinst = pd->pinst; 76 77 spin_lock(&pqueue->parallel.lock); 78 list_replace_init(&pqueue->parallel.list, &local_list); 79 spin_unlock(&pqueue->parallel.lock); 80 81 while (!list_empty(&local_list)) { 82 struct padata_priv *padata; 83 84 padata = list_entry(local_list.next, 85 struct padata_priv, list); 86 87 list_del_init(&padata->list); 88 89 padata->parallel(padata); 90 } 91 92 local_bh_enable(); 93 } 94 95 /** 96 * padata_do_parallel - padata parallelization function 97 * 98 * @pinst: padata instance 99 * @padata: object to be parallelized 100 * @cb_cpu: cpu the serialization callback function will run on, 101 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu). 102 * 103 * The parallelization callback function will run with BHs off. 104 * Note: Every object which is parallelized by padata_do_parallel 105 * must be seen by padata_do_serial. 106 */ 107 int padata_do_parallel(struct padata_instance *pinst, 108 struct padata_priv *padata, int cb_cpu) 109 { 110 int target_cpu, err; 111 struct padata_parallel_queue *queue; 112 struct parallel_data *pd; 113 114 rcu_read_lock_bh(); 115 116 pd = rcu_dereference(pinst->pd); 117 118 err = -EINVAL; 119 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID) 120 goto out; 121 122 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu)) 123 goto out; 124 125 err = -EBUSY; 126 if ((pinst->flags & PADATA_RESET)) 127 goto out; 128 129 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM) 130 goto out; 131 132 err = 0; 133 atomic_inc(&pd->refcnt); 134 padata->pd = pd; 135 padata->cb_cpu = cb_cpu; 136 137 target_cpu = padata_cpu_hash(pd); 138 queue = per_cpu_ptr(pd->pqueue, target_cpu); 139 140 spin_lock(&queue->parallel.lock); 141 list_add_tail(&padata->list, &queue->parallel.list); 142 spin_unlock(&queue->parallel.lock); 143 144 queue_work_on(target_cpu, pinst->wq, &queue->work); 145 146 out: 147 rcu_read_unlock_bh(); 148 149 return err; 150 } 151 EXPORT_SYMBOL(padata_do_parallel); 152 153 /* 154 * padata_get_next - Get the next object that needs serialization. 155 * 156 * Return values are: 157 * 158 * A pointer to the control struct of the next object that needs 159 * serialization, if present in one of the percpu reorder queues. 160 * 161 * NULL, if all percpu reorder queues are empty. 162 * 163 * -EINPROGRESS, if the next object that needs serialization will 164 * be parallel processed by another cpu and is not yet present in 165 * the cpu's reorder queue. 166 * 167 * -ENODATA, if this cpu has to do the parallel processing for 168 * the next object. 169 */ 170 static struct padata_priv *padata_get_next(struct parallel_data *pd) 171 { 172 int cpu, num_cpus; 173 unsigned int next_nr, next_index; 174 struct padata_parallel_queue *queue, *next_queue; 175 struct padata_priv *padata; 176 struct padata_list *reorder; 177 178 num_cpus = cpumask_weight(pd->cpumask.pcpu); 179 180 /* 181 * Calculate the percpu reorder queue and the sequence 182 * number of the next object. 183 */ 184 next_nr = pd->processed; 185 next_index = next_nr % num_cpus; 186 cpu = padata_index_to_cpu(pd, next_index); 187 next_queue = per_cpu_ptr(pd->pqueue, cpu); 188 189 padata = NULL; 190 191 reorder = &next_queue->reorder; 192 193 if (!list_empty(&reorder->list)) { 194 padata = list_entry(reorder->list.next, 195 struct padata_priv, list); 196 197 spin_lock(&reorder->lock); 198 list_del_init(&padata->list); 199 atomic_dec(&pd->reorder_objects); 200 spin_unlock(&reorder->lock); 201 202 pd->processed++; 203 204 goto out; 205 } 206 207 queue = per_cpu_ptr(pd->pqueue, smp_processor_id()); 208 if (queue->cpu_index == next_queue->cpu_index) { 209 padata = ERR_PTR(-ENODATA); 210 goto out; 211 } 212 213 padata = ERR_PTR(-EINPROGRESS); 214 out: 215 return padata; 216 } 217 218 static void padata_reorder(struct parallel_data *pd) 219 { 220 int cb_cpu; 221 struct padata_priv *padata; 222 struct padata_serial_queue *squeue; 223 struct padata_instance *pinst = pd->pinst; 224 225 /* 226 * We need to ensure that only one cpu can work on dequeueing of 227 * the reorder queue the time. Calculating in which percpu reorder 228 * queue the next object will arrive takes some time. A spinlock 229 * would be highly contended. Also it is not clear in which order 230 * the objects arrive to the reorder queues. So a cpu could wait to 231 * get the lock just to notice that there is nothing to do at the 232 * moment. Therefore we use a trylock and let the holder of the lock 233 * care for all the objects enqueued during the holdtime of the lock. 234 */ 235 if (!spin_trylock_bh(&pd->lock)) 236 return; 237 238 while (1) { 239 padata = padata_get_next(pd); 240 241 /* 242 * All reorder queues are empty, or the next object that needs 243 * serialization is parallel processed by another cpu and is 244 * still on it's way to the cpu's reorder queue, nothing to 245 * do for now. 246 */ 247 if (!padata || PTR_ERR(padata) == -EINPROGRESS) 248 break; 249 250 /* 251 * This cpu has to do the parallel processing of the next 252 * object. It's waiting in the cpu's parallelization queue, 253 * so exit immediately. 254 */ 255 if (PTR_ERR(padata) == -ENODATA) { 256 del_timer(&pd->timer); 257 spin_unlock_bh(&pd->lock); 258 return; 259 } 260 261 cb_cpu = padata->cb_cpu; 262 squeue = per_cpu_ptr(pd->squeue, cb_cpu); 263 264 spin_lock(&squeue->serial.lock); 265 list_add_tail(&padata->list, &squeue->serial.list); 266 spin_unlock(&squeue->serial.lock); 267 268 queue_work_on(cb_cpu, pinst->wq, &squeue->work); 269 } 270 271 spin_unlock_bh(&pd->lock); 272 273 /* 274 * The next object that needs serialization might have arrived to 275 * the reorder queues in the meantime, we will be called again 276 * from the timer function if no one else cares for it. 277 */ 278 if (atomic_read(&pd->reorder_objects) 279 && !(pinst->flags & PADATA_RESET)) 280 mod_timer(&pd->timer, jiffies + HZ); 281 else 282 del_timer(&pd->timer); 283 284 return; 285 } 286 287 static void padata_reorder_timer(unsigned long arg) 288 { 289 struct parallel_data *pd = (struct parallel_data *)arg; 290 291 padata_reorder(pd); 292 } 293 294 static void padata_serial_worker(struct work_struct *serial_work) 295 { 296 struct padata_serial_queue *squeue; 297 struct parallel_data *pd; 298 LIST_HEAD(local_list); 299 300 local_bh_disable(); 301 squeue = container_of(serial_work, struct padata_serial_queue, work); 302 pd = squeue->pd; 303 304 spin_lock(&squeue->serial.lock); 305 list_replace_init(&squeue->serial.list, &local_list); 306 spin_unlock(&squeue->serial.lock); 307 308 while (!list_empty(&local_list)) { 309 struct padata_priv *padata; 310 311 padata = list_entry(local_list.next, 312 struct padata_priv, list); 313 314 list_del_init(&padata->list); 315 316 padata->serial(padata); 317 atomic_dec(&pd->refcnt); 318 } 319 local_bh_enable(); 320 } 321 322 /** 323 * padata_do_serial - padata serialization function 324 * 325 * @padata: object to be serialized. 326 * 327 * padata_do_serial must be called for every parallelized object. 328 * The serialization callback function will run with BHs off. 329 */ 330 void padata_do_serial(struct padata_priv *padata) 331 { 332 int cpu; 333 struct padata_parallel_queue *pqueue; 334 struct parallel_data *pd; 335 336 pd = padata->pd; 337 338 cpu = get_cpu(); 339 pqueue = per_cpu_ptr(pd->pqueue, cpu); 340 341 spin_lock(&pqueue->reorder.lock); 342 atomic_inc(&pd->reorder_objects); 343 list_add_tail(&padata->list, &pqueue->reorder.list); 344 spin_unlock(&pqueue->reorder.lock); 345 346 put_cpu(); 347 348 padata_reorder(pd); 349 } 350 EXPORT_SYMBOL(padata_do_serial); 351 352 static int padata_setup_cpumasks(struct parallel_data *pd, 353 const struct cpumask *pcpumask, 354 const struct cpumask *cbcpumask) 355 { 356 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL)) 357 return -ENOMEM; 358 359 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask); 360 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) { 361 free_cpumask_var(pd->cpumask.cbcpu); 362 return -ENOMEM; 363 } 364 365 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask); 366 return 0; 367 } 368 369 static void __padata_list_init(struct padata_list *pd_list) 370 { 371 INIT_LIST_HEAD(&pd_list->list); 372 spin_lock_init(&pd_list->lock); 373 } 374 375 /* Initialize all percpu queues used by serial workers */ 376 static void padata_init_squeues(struct parallel_data *pd) 377 { 378 int cpu; 379 struct padata_serial_queue *squeue; 380 381 for_each_cpu(cpu, pd->cpumask.cbcpu) { 382 squeue = per_cpu_ptr(pd->squeue, cpu); 383 squeue->pd = pd; 384 __padata_list_init(&squeue->serial); 385 INIT_WORK(&squeue->work, padata_serial_worker); 386 } 387 } 388 389 /* Initialize all percpu queues used by parallel workers */ 390 static void padata_init_pqueues(struct parallel_data *pd) 391 { 392 int cpu_index, cpu; 393 struct padata_parallel_queue *pqueue; 394 395 cpu_index = 0; 396 for_each_cpu(cpu, pd->cpumask.pcpu) { 397 pqueue = per_cpu_ptr(pd->pqueue, cpu); 398 pqueue->pd = pd; 399 pqueue->cpu_index = cpu_index; 400 cpu_index++; 401 402 __padata_list_init(&pqueue->reorder); 403 __padata_list_init(&pqueue->parallel); 404 INIT_WORK(&pqueue->work, padata_parallel_worker); 405 atomic_set(&pqueue->num_obj, 0); 406 } 407 } 408 409 /* Allocate and initialize the internal cpumask dependend resources. */ 410 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst, 411 const struct cpumask *pcpumask, 412 const struct cpumask *cbcpumask) 413 { 414 struct parallel_data *pd; 415 416 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL); 417 if (!pd) 418 goto err; 419 420 pd->pqueue = alloc_percpu(struct padata_parallel_queue); 421 if (!pd->pqueue) 422 goto err_free_pd; 423 424 pd->squeue = alloc_percpu(struct padata_serial_queue); 425 if (!pd->squeue) 426 goto err_free_pqueue; 427 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0) 428 goto err_free_squeue; 429 430 padata_init_pqueues(pd); 431 padata_init_squeues(pd); 432 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd); 433 pd->seq_nr = 0; 434 atomic_set(&pd->reorder_objects, 0); 435 atomic_set(&pd->refcnt, 0); 436 pd->pinst = pinst; 437 spin_lock_init(&pd->lock); 438 439 return pd; 440 441 err_free_squeue: 442 free_percpu(pd->squeue); 443 err_free_pqueue: 444 free_percpu(pd->pqueue); 445 err_free_pd: 446 kfree(pd); 447 err: 448 return NULL; 449 } 450 451 static void padata_free_pd(struct parallel_data *pd) 452 { 453 free_cpumask_var(pd->cpumask.pcpu); 454 free_cpumask_var(pd->cpumask.cbcpu); 455 free_percpu(pd->pqueue); 456 free_percpu(pd->squeue); 457 kfree(pd); 458 } 459 460 /* Flush all objects out of the padata queues. */ 461 static void padata_flush_queues(struct parallel_data *pd) 462 { 463 int cpu; 464 struct padata_parallel_queue *pqueue; 465 struct padata_serial_queue *squeue; 466 467 for_each_cpu(cpu, pd->cpumask.pcpu) { 468 pqueue = per_cpu_ptr(pd->pqueue, cpu); 469 flush_work(&pqueue->work); 470 } 471 472 del_timer_sync(&pd->timer); 473 474 if (atomic_read(&pd->reorder_objects)) 475 padata_reorder(pd); 476 477 for_each_cpu(cpu, pd->cpumask.cbcpu) { 478 squeue = per_cpu_ptr(pd->squeue, cpu); 479 flush_work(&squeue->work); 480 } 481 482 BUG_ON(atomic_read(&pd->refcnt) != 0); 483 } 484 485 static void __padata_start(struct padata_instance *pinst) 486 { 487 pinst->flags |= PADATA_INIT; 488 } 489 490 static void __padata_stop(struct padata_instance *pinst) 491 { 492 if (!(pinst->flags & PADATA_INIT)) 493 return; 494 495 pinst->flags &= ~PADATA_INIT; 496 497 synchronize_rcu(); 498 499 get_online_cpus(); 500 padata_flush_queues(pinst->pd); 501 put_online_cpus(); 502 } 503 504 /* Replace the internal control structure with a new one. */ 505 static void padata_replace(struct padata_instance *pinst, 506 struct parallel_data *pd_new) 507 { 508 struct parallel_data *pd_old = pinst->pd; 509 int notification_mask = 0; 510 511 pinst->flags |= PADATA_RESET; 512 513 rcu_assign_pointer(pinst->pd, pd_new); 514 515 synchronize_rcu(); 516 517 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu)) 518 notification_mask |= PADATA_CPU_PARALLEL; 519 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu)) 520 notification_mask |= PADATA_CPU_SERIAL; 521 522 padata_flush_queues(pd_old); 523 padata_free_pd(pd_old); 524 525 if (notification_mask) 526 blocking_notifier_call_chain(&pinst->cpumask_change_notifier, 527 notification_mask, 528 &pd_new->cpumask); 529 530 pinst->flags &= ~PADATA_RESET; 531 } 532 533 /** 534 * padata_register_cpumask_notifier - Registers a notifier that will be called 535 * if either pcpu or cbcpu or both cpumasks change. 536 * 537 * @pinst: A poineter to padata instance 538 * @nblock: A pointer to notifier block. 539 */ 540 int padata_register_cpumask_notifier(struct padata_instance *pinst, 541 struct notifier_block *nblock) 542 { 543 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier, 544 nblock); 545 } 546 EXPORT_SYMBOL(padata_register_cpumask_notifier); 547 548 /** 549 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier 550 * registered earlier using padata_register_cpumask_notifier 551 * 552 * @pinst: A pointer to data instance. 553 * @nlock: A pointer to notifier block. 554 */ 555 int padata_unregister_cpumask_notifier(struct padata_instance *pinst, 556 struct notifier_block *nblock) 557 { 558 return blocking_notifier_chain_unregister( 559 &pinst->cpumask_change_notifier, 560 nblock); 561 } 562 EXPORT_SYMBOL(padata_unregister_cpumask_notifier); 563 564 565 /* If cpumask contains no active cpu, we mark the instance as invalid. */ 566 static bool padata_validate_cpumask(struct padata_instance *pinst, 567 const struct cpumask *cpumask) 568 { 569 if (!cpumask_intersects(cpumask, cpu_online_mask)) { 570 pinst->flags |= PADATA_INVALID; 571 return false; 572 } 573 574 pinst->flags &= ~PADATA_INVALID; 575 return true; 576 } 577 578 static int __padata_set_cpumasks(struct padata_instance *pinst, 579 cpumask_var_t pcpumask, 580 cpumask_var_t cbcpumask) 581 { 582 int valid; 583 struct parallel_data *pd; 584 585 valid = padata_validate_cpumask(pinst, pcpumask); 586 if (!valid) { 587 __padata_stop(pinst); 588 goto out_replace; 589 } 590 591 valid = padata_validate_cpumask(pinst, cbcpumask); 592 if (!valid) 593 __padata_stop(pinst); 594 595 out_replace: 596 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); 597 if (!pd) 598 return -ENOMEM; 599 600 cpumask_copy(pinst->cpumask.pcpu, pcpumask); 601 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); 602 603 padata_replace(pinst, pd); 604 605 if (valid) 606 __padata_start(pinst); 607 608 return 0; 609 } 610 611 /** 612 * padata_set_cpumasks - Set both parallel and serial cpumasks. The first 613 * one is used by parallel workers and the second one 614 * by the wokers doing serialization. 615 * 616 * @pinst: padata instance 617 * @pcpumask: the cpumask to use for parallel workers 618 * @cbcpumask: the cpumsak to use for serial workers 619 */ 620 int padata_set_cpumasks(struct padata_instance *pinst, cpumask_var_t pcpumask, 621 cpumask_var_t cbcpumask) 622 { 623 int err; 624 625 mutex_lock(&pinst->lock); 626 get_online_cpus(); 627 628 err = __padata_set_cpumasks(pinst, pcpumask, cbcpumask); 629 630 put_online_cpus(); 631 mutex_unlock(&pinst->lock); 632 633 return err; 634 635 } 636 EXPORT_SYMBOL(padata_set_cpumasks); 637 638 /** 639 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value 640 * equivalent to @cpumask. 641 * 642 * @pinst: padata instance 643 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding 644 * to parallel and serial cpumasks respectively. 645 * @cpumask: the cpumask to use 646 */ 647 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, 648 cpumask_var_t cpumask) 649 { 650 struct cpumask *serial_mask, *parallel_mask; 651 int err = -EINVAL; 652 653 mutex_lock(&pinst->lock); 654 get_online_cpus(); 655 656 switch (cpumask_type) { 657 case PADATA_CPU_PARALLEL: 658 serial_mask = pinst->cpumask.cbcpu; 659 parallel_mask = cpumask; 660 break; 661 case PADATA_CPU_SERIAL: 662 parallel_mask = pinst->cpumask.pcpu; 663 serial_mask = cpumask; 664 break; 665 default: 666 goto out; 667 } 668 669 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask); 670 671 out: 672 put_online_cpus(); 673 mutex_unlock(&pinst->lock); 674 675 return err; 676 } 677 EXPORT_SYMBOL(padata_set_cpumask); 678 679 static int __padata_add_cpu(struct padata_instance *pinst, int cpu) 680 { 681 struct parallel_data *pd; 682 683 if (cpumask_test_cpu(cpu, cpu_online_mask)) { 684 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, 685 pinst->cpumask.cbcpu); 686 if (!pd) 687 return -ENOMEM; 688 689 padata_replace(pinst, pd); 690 691 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) && 692 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) 693 __padata_start(pinst); 694 } 695 696 return 0; 697 } 698 699 /** 700 * padata_add_cpu - add a cpu to one or both(parallel and serial) 701 * padata cpumasks. 702 * 703 * @pinst: padata instance 704 * @cpu: cpu to add 705 * @mask: bitmask of flags specifying to which cpumask @cpu shuld be added. 706 * The @mask may be any combination of the following flags: 707 * PADATA_CPU_SERIAL - serial cpumask 708 * PADATA_CPU_PARALLEL - parallel cpumask 709 */ 710 711 int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask) 712 { 713 int err; 714 715 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL))) 716 return -EINVAL; 717 718 mutex_lock(&pinst->lock); 719 720 get_online_cpus(); 721 if (mask & PADATA_CPU_SERIAL) 722 cpumask_set_cpu(cpu, pinst->cpumask.cbcpu); 723 if (mask & PADATA_CPU_PARALLEL) 724 cpumask_set_cpu(cpu, pinst->cpumask.pcpu); 725 726 err = __padata_add_cpu(pinst, cpu); 727 put_online_cpus(); 728 729 mutex_unlock(&pinst->lock); 730 731 return err; 732 } 733 EXPORT_SYMBOL(padata_add_cpu); 734 735 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu) 736 { 737 struct parallel_data *pd = NULL; 738 739 if (cpumask_test_cpu(cpu, cpu_online_mask)) { 740 741 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) || 742 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) 743 __padata_stop(pinst); 744 745 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, 746 pinst->cpumask.cbcpu); 747 if (!pd) 748 return -ENOMEM; 749 750 padata_replace(pinst, pd); 751 752 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu); 753 cpumask_clear_cpu(cpu, pd->cpumask.pcpu); 754 } 755 756 return 0; 757 } 758 759 /** 760 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel) 761 * padata cpumasks. 762 * 763 * @pinst: padata instance 764 * @cpu: cpu to remove 765 * @mask: bitmask specifying from which cpumask @cpu should be removed 766 * The @mask may be any combination of the following flags: 767 * PADATA_CPU_SERIAL - serial cpumask 768 * PADATA_CPU_PARALLEL - parallel cpumask 769 */ 770 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask) 771 { 772 int err; 773 774 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL))) 775 return -EINVAL; 776 777 mutex_lock(&pinst->lock); 778 779 get_online_cpus(); 780 if (mask & PADATA_CPU_SERIAL) 781 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu); 782 if (mask & PADATA_CPU_PARALLEL) 783 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu); 784 785 err = __padata_remove_cpu(pinst, cpu); 786 put_online_cpus(); 787 788 mutex_unlock(&pinst->lock); 789 790 return err; 791 } 792 EXPORT_SYMBOL(padata_remove_cpu); 793 794 /** 795 * padata_start - start the parallel processing 796 * 797 * @pinst: padata instance to start 798 */ 799 int padata_start(struct padata_instance *pinst) 800 { 801 int err = 0; 802 803 mutex_lock(&pinst->lock); 804 805 if (pinst->flags & PADATA_INVALID) 806 err =-EINVAL; 807 808 __padata_start(pinst); 809 810 mutex_unlock(&pinst->lock); 811 812 return err; 813 } 814 EXPORT_SYMBOL(padata_start); 815 816 /** 817 * padata_stop - stop the parallel processing 818 * 819 * @pinst: padata instance to stop 820 */ 821 void padata_stop(struct padata_instance *pinst) 822 { 823 mutex_lock(&pinst->lock); 824 __padata_stop(pinst); 825 mutex_unlock(&pinst->lock); 826 } 827 EXPORT_SYMBOL(padata_stop); 828 829 #ifdef CONFIG_HOTPLUG_CPU 830 831 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu) 832 { 833 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) || 834 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu); 835 } 836 837 838 static int padata_cpu_callback(struct notifier_block *nfb, 839 unsigned long action, void *hcpu) 840 { 841 int err; 842 struct padata_instance *pinst; 843 int cpu = (unsigned long)hcpu; 844 845 pinst = container_of(nfb, struct padata_instance, cpu_notifier); 846 847 switch (action) { 848 case CPU_ONLINE: 849 case CPU_ONLINE_FROZEN: 850 if (!pinst_has_cpu(pinst, cpu)) 851 break; 852 mutex_lock(&pinst->lock); 853 err = __padata_add_cpu(pinst, cpu); 854 mutex_unlock(&pinst->lock); 855 if (err) 856 return notifier_from_errno(err); 857 break; 858 859 case CPU_DOWN_PREPARE: 860 case CPU_DOWN_PREPARE_FROZEN: 861 if (!pinst_has_cpu(pinst, cpu)) 862 break; 863 mutex_lock(&pinst->lock); 864 err = __padata_remove_cpu(pinst, cpu); 865 mutex_unlock(&pinst->lock); 866 if (err) 867 return notifier_from_errno(err); 868 break; 869 870 case CPU_UP_CANCELED: 871 case CPU_UP_CANCELED_FROZEN: 872 if (!pinst_has_cpu(pinst, cpu)) 873 break; 874 mutex_lock(&pinst->lock); 875 __padata_remove_cpu(pinst, cpu); 876 mutex_unlock(&pinst->lock); 877 878 case CPU_DOWN_FAILED: 879 case CPU_DOWN_FAILED_FROZEN: 880 if (!pinst_has_cpu(pinst, cpu)) 881 break; 882 mutex_lock(&pinst->lock); 883 __padata_add_cpu(pinst, cpu); 884 mutex_unlock(&pinst->lock); 885 } 886 887 return NOTIFY_OK; 888 } 889 #endif 890 891 static void __padata_free(struct padata_instance *pinst) 892 { 893 #ifdef CONFIG_HOTPLUG_CPU 894 unregister_hotcpu_notifier(&pinst->cpu_notifier); 895 #endif 896 897 padata_stop(pinst); 898 padata_free_pd(pinst->pd); 899 free_cpumask_var(pinst->cpumask.pcpu); 900 free_cpumask_var(pinst->cpumask.cbcpu); 901 kfree(pinst); 902 } 903 904 #define kobj2pinst(_kobj) \ 905 container_of(_kobj, struct padata_instance, kobj) 906 #define attr2pentry(_attr) \ 907 container_of(_attr, struct padata_sysfs_entry, attr) 908 909 static void padata_sysfs_release(struct kobject *kobj) 910 { 911 struct padata_instance *pinst = kobj2pinst(kobj); 912 __padata_free(pinst); 913 } 914 915 struct padata_sysfs_entry { 916 struct attribute attr; 917 ssize_t (*show)(struct padata_instance *, struct attribute *, char *); 918 ssize_t (*store)(struct padata_instance *, struct attribute *, 919 const char *, size_t); 920 }; 921 922 static ssize_t show_cpumask(struct padata_instance *pinst, 923 struct attribute *attr, char *buf) 924 { 925 struct cpumask *cpumask; 926 ssize_t len; 927 928 mutex_lock(&pinst->lock); 929 if (!strcmp(attr->name, "serial_cpumask")) 930 cpumask = pinst->cpumask.cbcpu; 931 else 932 cpumask = pinst->cpumask.pcpu; 933 934 len = bitmap_scnprintf(buf, PAGE_SIZE, cpumask_bits(cpumask), 935 nr_cpu_ids); 936 if (PAGE_SIZE - len < 2) 937 len = -EINVAL; 938 else 939 len += sprintf(buf + len, "\n"); 940 941 mutex_unlock(&pinst->lock); 942 return len; 943 } 944 945 static ssize_t store_cpumask(struct padata_instance *pinst, 946 struct attribute *attr, 947 const char *buf, size_t count) 948 { 949 cpumask_var_t new_cpumask; 950 ssize_t ret; 951 int mask_type; 952 953 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL)) 954 return -ENOMEM; 955 956 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask), 957 nr_cpumask_bits); 958 if (ret < 0) 959 goto out; 960 961 mask_type = !strcmp(attr->name, "serial_cpumask") ? 962 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL; 963 ret = padata_set_cpumask(pinst, mask_type, new_cpumask); 964 if (!ret) 965 ret = count; 966 967 out: 968 free_cpumask_var(new_cpumask); 969 return ret; 970 } 971 972 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \ 973 static struct padata_sysfs_entry _name##_attr = \ 974 __ATTR(_name, 0644, _show_name, _store_name) 975 #define PADATA_ATTR_RO(_name, _show_name) \ 976 static struct padata_sysfs_entry _name##_attr = \ 977 __ATTR(_name, 0400, _show_name, NULL) 978 979 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask); 980 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask); 981 982 /* 983 * Padata sysfs provides the following objects: 984 * serial_cpumask [RW] - cpumask for serial workers 985 * parallel_cpumask [RW] - cpumask for parallel workers 986 */ 987 static struct attribute *padata_default_attrs[] = { 988 &serial_cpumask_attr.attr, 989 ¶llel_cpumask_attr.attr, 990 NULL, 991 }; 992 993 static ssize_t padata_sysfs_show(struct kobject *kobj, 994 struct attribute *attr, char *buf) 995 { 996 struct padata_instance *pinst; 997 struct padata_sysfs_entry *pentry; 998 ssize_t ret = -EIO; 999 1000 pinst = kobj2pinst(kobj); 1001 pentry = attr2pentry(attr); 1002 if (pentry->show) 1003 ret = pentry->show(pinst, attr, buf); 1004 1005 return ret; 1006 } 1007 1008 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr, 1009 const char *buf, size_t count) 1010 { 1011 struct padata_instance *pinst; 1012 struct padata_sysfs_entry *pentry; 1013 ssize_t ret = -EIO; 1014 1015 pinst = kobj2pinst(kobj); 1016 pentry = attr2pentry(attr); 1017 if (pentry->show) 1018 ret = pentry->store(pinst, attr, buf, count); 1019 1020 return ret; 1021 } 1022 1023 static const struct sysfs_ops padata_sysfs_ops = { 1024 .show = padata_sysfs_show, 1025 .store = padata_sysfs_store, 1026 }; 1027 1028 static struct kobj_type padata_attr_type = { 1029 .sysfs_ops = &padata_sysfs_ops, 1030 .default_attrs = padata_default_attrs, 1031 .release = padata_sysfs_release, 1032 }; 1033 1034 /** 1035 * padata_alloc_possible - Allocate and initialize padata instance. 1036 * Use the cpu_possible_mask for serial and 1037 * parallel workers. 1038 * 1039 * @wq: workqueue to use for the allocated padata instance 1040 */ 1041 struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq) 1042 { 1043 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask); 1044 } 1045 EXPORT_SYMBOL(padata_alloc_possible); 1046 1047 /** 1048 * padata_alloc - allocate and initialize a padata instance and specify 1049 * cpumasks for serial and parallel workers. 1050 * 1051 * @wq: workqueue to use for the allocated padata instance 1052 * @pcpumask: cpumask that will be used for padata parallelization 1053 * @cbcpumask: cpumask that will be used for padata serialization 1054 */ 1055 struct padata_instance *padata_alloc(struct workqueue_struct *wq, 1056 const struct cpumask *pcpumask, 1057 const struct cpumask *cbcpumask) 1058 { 1059 struct padata_instance *pinst; 1060 struct parallel_data *pd = NULL; 1061 1062 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL); 1063 if (!pinst) 1064 goto err; 1065 1066 get_online_cpus(); 1067 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL)) 1068 goto err_free_inst; 1069 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) { 1070 free_cpumask_var(pinst->cpumask.pcpu); 1071 goto err_free_inst; 1072 } 1073 if (!padata_validate_cpumask(pinst, pcpumask) || 1074 !padata_validate_cpumask(pinst, cbcpumask)) 1075 goto err_free_masks; 1076 1077 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); 1078 if (!pd) 1079 goto err_free_masks; 1080 1081 rcu_assign_pointer(pinst->pd, pd); 1082 1083 pinst->wq = wq; 1084 1085 cpumask_copy(pinst->cpumask.pcpu, pcpumask); 1086 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); 1087 1088 pinst->flags = 0; 1089 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); 1094 #endif 1095 1096 put_online_cpus(); 1097 1098 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier); 1099 kobject_init(&pinst->kobj, &padata_attr_type); 1100 mutex_init(&pinst->lock); 1101 1102 return pinst; 1103 1104 err_free_masks: 1105 free_cpumask_var(pinst->cpumask.pcpu); 1106 free_cpumask_var(pinst->cpumask.cbcpu); 1107 err_free_inst: 1108 kfree(pinst); 1109 put_online_cpus(); 1110 err: 1111 return NULL; 1112 } 1113 EXPORT_SYMBOL(padata_alloc); 1114 1115 /** 1116 * padata_free - free a padata instance 1117 * 1118 * @padata_inst: padata instance to free 1119 */ 1120 void padata_free(struct padata_instance *pinst) 1121 { 1122 kobject_put(&pinst->kobj); 1123 } 1124 EXPORT_SYMBOL(padata_free); 1125