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 #include <linux/module.h> 34 35 #define MAX_OBJ_NUM 1000 36 37 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index) 38 { 39 int cpu, target_cpu; 40 41 target_cpu = cpumask_first(pd->cpumask.pcpu); 42 for (cpu = 0; cpu < cpu_index; cpu++) 43 target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu); 44 45 return target_cpu; 46 } 47 48 static int padata_cpu_hash(struct parallel_data *pd) 49 { 50 unsigned int seq_nr; 51 int cpu_index; 52 53 /* 54 * Hash the sequence numbers to the cpus by taking 55 * seq_nr mod. number of cpus in use. 56 */ 57 58 seq_nr = atomic_inc_return(&pd->seq_nr); 59 cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu); 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 LIST_HEAD(local_list); 68 69 local_bh_disable(); 70 pqueue = container_of(parallel_work, 71 struct padata_parallel_queue, work); 72 73 spin_lock(&pqueue->parallel.lock); 74 list_replace_init(&pqueue->parallel.list, &local_list); 75 spin_unlock(&pqueue->parallel.lock); 76 77 while (!list_empty(&local_list)) { 78 struct padata_priv *padata; 79 80 padata = list_entry(local_list.next, 81 struct padata_priv, list); 82 83 list_del_init(&padata->list); 84 85 padata->parallel(padata); 86 } 87 88 local_bh_enable(); 89 } 90 91 /** 92 * padata_do_parallel - padata parallelization function 93 * 94 * @pinst: padata instance 95 * @padata: object to be parallelized 96 * @cb_cpu: cpu the serialization callback function will run on, 97 * must be in the serial cpumask of padata(i.e. cpumask.cbcpu). 98 * 99 * The parallelization callback function will run with BHs off. 100 * Note: Every object which is parallelized by padata_do_parallel 101 * must be seen by padata_do_serial. 102 */ 103 int padata_do_parallel(struct padata_instance *pinst, 104 struct padata_priv *padata, int cb_cpu) 105 { 106 int target_cpu, err; 107 struct padata_parallel_queue *queue; 108 struct parallel_data *pd; 109 110 rcu_read_lock_bh(); 111 112 pd = rcu_dereference_bh(pinst->pd); 113 114 err = -EINVAL; 115 if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID) 116 goto out; 117 118 if (!cpumask_test_cpu(cb_cpu, pd->cpumask.cbcpu)) 119 goto out; 120 121 err = -EBUSY; 122 if ((pinst->flags & PADATA_RESET)) 123 goto out; 124 125 if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM) 126 goto out; 127 128 err = 0; 129 atomic_inc(&pd->refcnt); 130 padata->pd = pd; 131 padata->cb_cpu = cb_cpu; 132 133 target_cpu = padata_cpu_hash(pd); 134 queue = per_cpu_ptr(pd->pqueue, target_cpu); 135 136 spin_lock(&queue->parallel.lock); 137 list_add_tail(&padata->list, &queue->parallel.list); 138 spin_unlock(&queue->parallel.lock); 139 140 queue_work_on(target_cpu, pinst->wq, &queue->work); 141 142 out: 143 rcu_read_unlock_bh(); 144 145 return err; 146 } 147 EXPORT_SYMBOL(padata_do_parallel); 148 149 /* 150 * padata_get_next - Get the next object that needs serialization. 151 * 152 * Return values are: 153 * 154 * A pointer to the control struct of the next object that needs 155 * serialization, if present in one of the percpu reorder queues. 156 * 157 * -EINPROGRESS, if the next object that needs serialization will 158 * be parallel processed by another cpu and is not yet present in 159 * the cpu's reorder queue. 160 * 161 * -ENODATA, if this cpu has to do the parallel processing for 162 * the next object. 163 */ 164 static struct padata_priv *padata_get_next(struct parallel_data *pd) 165 { 166 int cpu, num_cpus; 167 unsigned int next_nr, next_index; 168 struct padata_parallel_queue *next_queue; 169 struct padata_priv *padata; 170 struct padata_list *reorder; 171 172 num_cpus = cpumask_weight(pd->cpumask.pcpu); 173 174 /* 175 * Calculate the percpu reorder queue and the sequence 176 * number of the next object. 177 */ 178 next_nr = pd->processed; 179 next_index = next_nr % num_cpus; 180 cpu = padata_index_to_cpu(pd, next_index); 181 next_queue = per_cpu_ptr(pd->pqueue, cpu); 182 183 reorder = &next_queue->reorder; 184 185 spin_lock(&reorder->lock); 186 if (!list_empty(&reorder->list)) { 187 padata = list_entry(reorder->list.next, 188 struct padata_priv, list); 189 190 list_del_init(&padata->list); 191 atomic_dec(&pd->reorder_objects); 192 193 pd->processed++; 194 195 spin_unlock(&reorder->lock); 196 goto out; 197 } 198 spin_unlock(&reorder->lock); 199 200 if (__this_cpu_read(pd->pqueue->cpu_index) == next_queue->cpu_index) { 201 padata = ERR_PTR(-ENODATA); 202 goto out; 203 } 204 205 padata = ERR_PTR(-EINPROGRESS); 206 out: 207 return padata; 208 } 209 210 static void padata_reorder(struct parallel_data *pd) 211 { 212 int cb_cpu; 213 struct padata_priv *padata; 214 struct padata_serial_queue *squeue; 215 struct padata_instance *pinst = pd->pinst; 216 217 /* 218 * We need to ensure that only one cpu can work on dequeueing of 219 * the reorder queue the time. Calculating in which percpu reorder 220 * queue the next object will arrive takes some time. A spinlock 221 * would be highly contended. Also it is not clear in which order 222 * the objects arrive to the reorder queues. So a cpu could wait to 223 * get the lock just to notice that there is nothing to do at the 224 * moment. Therefore we use a trylock and let the holder of the lock 225 * care for all the objects enqueued during the holdtime of the lock. 226 */ 227 if (!spin_trylock_bh(&pd->lock)) 228 return; 229 230 while (1) { 231 padata = padata_get_next(pd); 232 233 /* 234 * If the next object that needs serialization is parallel 235 * processed by another cpu and is still on it's way to the 236 * cpu's reorder queue, nothing to do for now. 237 */ 238 if (PTR_ERR(padata) == -EINPROGRESS) 239 break; 240 241 /* 242 * This cpu has to do the parallel processing of the next 243 * object. It's waiting in the cpu's parallelization queue, 244 * so exit immediately. 245 */ 246 if (PTR_ERR(padata) == -ENODATA) { 247 del_timer(&pd->timer); 248 spin_unlock_bh(&pd->lock); 249 return; 250 } 251 252 cb_cpu = padata->cb_cpu; 253 squeue = per_cpu_ptr(pd->squeue, cb_cpu); 254 255 spin_lock(&squeue->serial.lock); 256 list_add_tail(&padata->list, &squeue->serial.list); 257 spin_unlock(&squeue->serial.lock); 258 259 queue_work_on(cb_cpu, pinst->wq, &squeue->work); 260 } 261 262 spin_unlock_bh(&pd->lock); 263 264 /* 265 * The next object that needs serialization might have arrived to 266 * the reorder queues in the meantime, we will be called again 267 * from the timer function if no one else cares for it. 268 */ 269 if (atomic_read(&pd->reorder_objects) 270 && !(pinst->flags & PADATA_RESET)) 271 mod_timer(&pd->timer, jiffies + HZ); 272 else 273 del_timer(&pd->timer); 274 275 return; 276 } 277 278 static void padata_reorder_timer(unsigned long arg) 279 { 280 struct parallel_data *pd = (struct parallel_data *)arg; 281 282 padata_reorder(pd); 283 } 284 285 static void padata_serial_worker(struct work_struct *serial_work) 286 { 287 struct padata_serial_queue *squeue; 288 struct parallel_data *pd; 289 LIST_HEAD(local_list); 290 291 local_bh_disable(); 292 squeue = container_of(serial_work, struct padata_serial_queue, work); 293 pd = squeue->pd; 294 295 spin_lock(&squeue->serial.lock); 296 list_replace_init(&squeue->serial.list, &local_list); 297 spin_unlock(&squeue->serial.lock); 298 299 while (!list_empty(&local_list)) { 300 struct padata_priv *padata; 301 302 padata = list_entry(local_list.next, 303 struct padata_priv, list); 304 305 list_del_init(&padata->list); 306 307 padata->serial(padata); 308 atomic_dec(&pd->refcnt); 309 } 310 local_bh_enable(); 311 } 312 313 /** 314 * padata_do_serial - padata serialization function 315 * 316 * @padata: object to be serialized. 317 * 318 * padata_do_serial must be called for every parallelized object. 319 * The serialization callback function will run with BHs off. 320 */ 321 void padata_do_serial(struct padata_priv *padata) 322 { 323 int cpu; 324 struct padata_parallel_queue *pqueue; 325 struct parallel_data *pd; 326 327 pd = padata->pd; 328 329 cpu = get_cpu(); 330 pqueue = per_cpu_ptr(pd->pqueue, cpu); 331 332 spin_lock(&pqueue->reorder.lock); 333 atomic_inc(&pd->reorder_objects); 334 list_add_tail(&padata->list, &pqueue->reorder.list); 335 spin_unlock(&pqueue->reorder.lock); 336 337 put_cpu(); 338 339 padata_reorder(pd); 340 } 341 EXPORT_SYMBOL(padata_do_serial); 342 343 static int padata_setup_cpumasks(struct parallel_data *pd, 344 const struct cpumask *pcpumask, 345 const struct cpumask *cbcpumask) 346 { 347 if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL)) 348 return -ENOMEM; 349 350 cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask); 351 if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) { 352 free_cpumask_var(pd->cpumask.pcpu); 353 return -ENOMEM; 354 } 355 356 cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask); 357 return 0; 358 } 359 360 static void __padata_list_init(struct padata_list *pd_list) 361 { 362 INIT_LIST_HEAD(&pd_list->list); 363 spin_lock_init(&pd_list->lock); 364 } 365 366 /* Initialize all percpu queues used by serial workers */ 367 static void padata_init_squeues(struct parallel_data *pd) 368 { 369 int cpu; 370 struct padata_serial_queue *squeue; 371 372 for_each_cpu(cpu, pd->cpumask.cbcpu) { 373 squeue = per_cpu_ptr(pd->squeue, cpu); 374 squeue->pd = pd; 375 __padata_list_init(&squeue->serial); 376 INIT_WORK(&squeue->work, padata_serial_worker); 377 } 378 } 379 380 /* Initialize all percpu queues used by parallel workers */ 381 static void padata_init_pqueues(struct parallel_data *pd) 382 { 383 int cpu_index, cpu; 384 struct padata_parallel_queue *pqueue; 385 386 cpu_index = 0; 387 for_each_cpu(cpu, pd->cpumask.pcpu) { 388 pqueue = per_cpu_ptr(pd->pqueue, cpu); 389 pqueue->pd = pd; 390 pqueue->cpu_index = cpu_index; 391 cpu_index++; 392 393 __padata_list_init(&pqueue->reorder); 394 __padata_list_init(&pqueue->parallel); 395 INIT_WORK(&pqueue->work, padata_parallel_worker); 396 atomic_set(&pqueue->num_obj, 0); 397 } 398 } 399 400 /* Allocate and initialize the internal cpumask dependend resources. */ 401 static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst, 402 const struct cpumask *pcpumask, 403 const struct cpumask *cbcpumask) 404 { 405 struct parallel_data *pd; 406 407 pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL); 408 if (!pd) 409 goto err; 410 411 pd->pqueue = alloc_percpu(struct padata_parallel_queue); 412 if (!pd->pqueue) 413 goto err_free_pd; 414 415 pd->squeue = alloc_percpu(struct padata_serial_queue); 416 if (!pd->squeue) 417 goto err_free_pqueue; 418 if (padata_setup_cpumasks(pd, pcpumask, cbcpumask) < 0) 419 goto err_free_squeue; 420 421 padata_init_pqueues(pd); 422 padata_init_squeues(pd); 423 setup_timer(&pd->timer, padata_reorder_timer, (unsigned long)pd); 424 atomic_set(&pd->seq_nr, -1); 425 atomic_set(&pd->reorder_objects, 0); 426 atomic_set(&pd->refcnt, 0); 427 pd->pinst = pinst; 428 spin_lock_init(&pd->lock); 429 430 return pd; 431 432 err_free_squeue: 433 free_percpu(pd->squeue); 434 err_free_pqueue: 435 free_percpu(pd->pqueue); 436 err_free_pd: 437 kfree(pd); 438 err: 439 return NULL; 440 } 441 442 static void padata_free_pd(struct parallel_data *pd) 443 { 444 free_cpumask_var(pd->cpumask.pcpu); 445 free_cpumask_var(pd->cpumask.cbcpu); 446 free_percpu(pd->pqueue); 447 free_percpu(pd->squeue); 448 kfree(pd); 449 } 450 451 /* Flush all objects out of the padata queues. */ 452 static void padata_flush_queues(struct parallel_data *pd) 453 { 454 int cpu; 455 struct padata_parallel_queue *pqueue; 456 struct padata_serial_queue *squeue; 457 458 for_each_cpu(cpu, pd->cpumask.pcpu) { 459 pqueue = per_cpu_ptr(pd->pqueue, cpu); 460 flush_work(&pqueue->work); 461 } 462 463 del_timer_sync(&pd->timer); 464 465 if (atomic_read(&pd->reorder_objects)) 466 padata_reorder(pd); 467 468 for_each_cpu(cpu, pd->cpumask.cbcpu) { 469 squeue = per_cpu_ptr(pd->squeue, cpu); 470 flush_work(&squeue->work); 471 } 472 473 BUG_ON(atomic_read(&pd->refcnt) != 0); 474 } 475 476 static void __padata_start(struct padata_instance *pinst) 477 { 478 pinst->flags |= PADATA_INIT; 479 } 480 481 static void __padata_stop(struct padata_instance *pinst) 482 { 483 if (!(pinst->flags & PADATA_INIT)) 484 return; 485 486 pinst->flags &= ~PADATA_INIT; 487 488 synchronize_rcu(); 489 490 get_online_cpus(); 491 padata_flush_queues(pinst->pd); 492 put_online_cpus(); 493 } 494 495 /* Replace the internal control structure with a new one. */ 496 static void padata_replace(struct padata_instance *pinst, 497 struct parallel_data *pd_new) 498 { 499 struct parallel_data *pd_old = pinst->pd; 500 int notification_mask = 0; 501 502 pinst->flags |= PADATA_RESET; 503 504 rcu_assign_pointer(pinst->pd, pd_new); 505 506 synchronize_rcu(); 507 508 if (!cpumask_equal(pd_old->cpumask.pcpu, pd_new->cpumask.pcpu)) 509 notification_mask |= PADATA_CPU_PARALLEL; 510 if (!cpumask_equal(pd_old->cpumask.cbcpu, pd_new->cpumask.cbcpu)) 511 notification_mask |= PADATA_CPU_SERIAL; 512 513 padata_flush_queues(pd_old); 514 padata_free_pd(pd_old); 515 516 if (notification_mask) 517 blocking_notifier_call_chain(&pinst->cpumask_change_notifier, 518 notification_mask, 519 &pd_new->cpumask); 520 521 pinst->flags &= ~PADATA_RESET; 522 } 523 524 /** 525 * padata_register_cpumask_notifier - Registers a notifier that will be called 526 * if either pcpu or cbcpu or both cpumasks change. 527 * 528 * @pinst: A poineter to padata instance 529 * @nblock: A pointer to notifier block. 530 */ 531 int padata_register_cpumask_notifier(struct padata_instance *pinst, 532 struct notifier_block *nblock) 533 { 534 return blocking_notifier_chain_register(&pinst->cpumask_change_notifier, 535 nblock); 536 } 537 EXPORT_SYMBOL(padata_register_cpumask_notifier); 538 539 /** 540 * padata_unregister_cpumask_notifier - Unregisters cpumask notifier 541 * registered earlier using padata_register_cpumask_notifier 542 * 543 * @pinst: A pointer to data instance. 544 * @nlock: A pointer to notifier block. 545 */ 546 int padata_unregister_cpumask_notifier(struct padata_instance *pinst, 547 struct notifier_block *nblock) 548 { 549 return blocking_notifier_chain_unregister( 550 &pinst->cpumask_change_notifier, 551 nblock); 552 } 553 EXPORT_SYMBOL(padata_unregister_cpumask_notifier); 554 555 556 /* If cpumask contains no active cpu, we mark the instance as invalid. */ 557 static bool padata_validate_cpumask(struct padata_instance *pinst, 558 const struct cpumask *cpumask) 559 { 560 if (!cpumask_intersects(cpumask, cpu_online_mask)) { 561 pinst->flags |= PADATA_INVALID; 562 return false; 563 } 564 565 pinst->flags &= ~PADATA_INVALID; 566 return true; 567 } 568 569 static int __padata_set_cpumasks(struct padata_instance *pinst, 570 cpumask_var_t pcpumask, 571 cpumask_var_t cbcpumask) 572 { 573 int valid; 574 struct parallel_data *pd; 575 576 valid = padata_validate_cpumask(pinst, pcpumask); 577 if (!valid) { 578 __padata_stop(pinst); 579 goto out_replace; 580 } 581 582 valid = padata_validate_cpumask(pinst, cbcpumask); 583 if (!valid) 584 __padata_stop(pinst); 585 586 out_replace: 587 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); 588 if (!pd) 589 return -ENOMEM; 590 591 cpumask_copy(pinst->cpumask.pcpu, pcpumask); 592 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); 593 594 padata_replace(pinst, pd); 595 596 if (valid) 597 __padata_start(pinst); 598 599 return 0; 600 } 601 602 /** 603 * padata_set_cpumask: Sets specified by @cpumask_type cpumask to the value 604 * equivalent to @cpumask. 605 * 606 * @pinst: padata instance 607 * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding 608 * to parallel and serial cpumasks respectively. 609 * @cpumask: the cpumask to use 610 */ 611 int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type, 612 cpumask_var_t cpumask) 613 { 614 struct cpumask *serial_mask, *parallel_mask; 615 int err = -EINVAL; 616 617 mutex_lock(&pinst->lock); 618 get_online_cpus(); 619 620 switch (cpumask_type) { 621 case PADATA_CPU_PARALLEL: 622 serial_mask = pinst->cpumask.cbcpu; 623 parallel_mask = cpumask; 624 break; 625 case PADATA_CPU_SERIAL: 626 parallel_mask = pinst->cpumask.pcpu; 627 serial_mask = cpumask; 628 break; 629 default: 630 goto out; 631 } 632 633 err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask); 634 635 out: 636 put_online_cpus(); 637 mutex_unlock(&pinst->lock); 638 639 return err; 640 } 641 EXPORT_SYMBOL(padata_set_cpumask); 642 643 /** 644 * padata_start - start the parallel processing 645 * 646 * @pinst: padata instance to start 647 */ 648 int padata_start(struct padata_instance *pinst) 649 { 650 int err = 0; 651 652 mutex_lock(&pinst->lock); 653 654 if (pinst->flags & PADATA_INVALID) 655 err = -EINVAL; 656 657 __padata_start(pinst); 658 659 mutex_unlock(&pinst->lock); 660 661 return err; 662 } 663 EXPORT_SYMBOL(padata_start); 664 665 /** 666 * padata_stop - stop the parallel processing 667 * 668 * @pinst: padata instance to stop 669 */ 670 void padata_stop(struct padata_instance *pinst) 671 { 672 mutex_lock(&pinst->lock); 673 __padata_stop(pinst); 674 mutex_unlock(&pinst->lock); 675 } 676 EXPORT_SYMBOL(padata_stop); 677 678 #ifdef CONFIG_HOTPLUG_CPU 679 680 static int __padata_add_cpu(struct padata_instance *pinst, int cpu) 681 { 682 struct parallel_data *pd; 683 684 if (cpumask_test_cpu(cpu, cpu_online_mask)) { 685 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, 686 pinst->cpumask.cbcpu); 687 if (!pd) 688 return -ENOMEM; 689 690 padata_replace(pinst, pd); 691 692 if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) && 693 padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) 694 __padata_start(pinst); 695 } 696 697 return 0; 698 } 699 700 static int __padata_remove_cpu(struct padata_instance *pinst, int cpu) 701 { 702 struct parallel_data *pd = NULL; 703 704 if (cpumask_test_cpu(cpu, cpu_online_mask)) { 705 706 if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) || 707 !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu)) 708 __padata_stop(pinst); 709 710 pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu, 711 pinst->cpumask.cbcpu); 712 if (!pd) 713 return -ENOMEM; 714 715 padata_replace(pinst, pd); 716 717 cpumask_clear_cpu(cpu, pd->cpumask.cbcpu); 718 cpumask_clear_cpu(cpu, pd->cpumask.pcpu); 719 } 720 721 return 0; 722 } 723 724 /** 725 * padata_remove_cpu - remove a cpu from the one or both(serial and parallel) 726 * padata cpumasks. 727 * 728 * @pinst: padata instance 729 * @cpu: cpu to remove 730 * @mask: bitmask specifying from which cpumask @cpu should be removed 731 * The @mask may be any combination of the following flags: 732 * PADATA_CPU_SERIAL - serial cpumask 733 * PADATA_CPU_PARALLEL - parallel cpumask 734 */ 735 int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask) 736 { 737 int err; 738 739 if (!(mask & (PADATA_CPU_SERIAL | PADATA_CPU_PARALLEL))) 740 return -EINVAL; 741 742 mutex_lock(&pinst->lock); 743 744 get_online_cpus(); 745 if (mask & PADATA_CPU_SERIAL) 746 cpumask_clear_cpu(cpu, pinst->cpumask.cbcpu); 747 if (mask & PADATA_CPU_PARALLEL) 748 cpumask_clear_cpu(cpu, pinst->cpumask.pcpu); 749 750 err = __padata_remove_cpu(pinst, cpu); 751 put_online_cpus(); 752 753 mutex_unlock(&pinst->lock); 754 755 return err; 756 } 757 EXPORT_SYMBOL(padata_remove_cpu); 758 759 static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu) 760 { 761 return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) || 762 cpumask_test_cpu(cpu, pinst->cpumask.cbcpu); 763 } 764 765 static int padata_cpu_online(unsigned int cpu, struct hlist_node *node) 766 { 767 struct padata_instance *pinst; 768 int ret; 769 770 pinst = hlist_entry_safe(node, struct padata_instance, node); 771 if (!pinst_has_cpu(pinst, cpu)) 772 return 0; 773 774 mutex_lock(&pinst->lock); 775 ret = __padata_add_cpu(pinst, cpu); 776 mutex_unlock(&pinst->lock); 777 return ret; 778 } 779 780 static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node) 781 { 782 struct padata_instance *pinst; 783 int ret; 784 785 pinst = hlist_entry_safe(node, struct padata_instance, node); 786 if (!pinst_has_cpu(pinst, cpu)) 787 return 0; 788 789 mutex_lock(&pinst->lock); 790 ret = __padata_remove_cpu(pinst, cpu); 791 mutex_unlock(&pinst->lock); 792 return ret; 793 } 794 795 static enum cpuhp_state hp_online; 796 #endif 797 798 static void __padata_free(struct padata_instance *pinst) 799 { 800 #ifdef CONFIG_HOTPLUG_CPU 801 cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node); 802 #endif 803 804 padata_stop(pinst); 805 padata_free_pd(pinst->pd); 806 free_cpumask_var(pinst->cpumask.pcpu); 807 free_cpumask_var(pinst->cpumask.cbcpu); 808 kfree(pinst); 809 } 810 811 #define kobj2pinst(_kobj) \ 812 container_of(_kobj, struct padata_instance, kobj) 813 #define attr2pentry(_attr) \ 814 container_of(_attr, struct padata_sysfs_entry, attr) 815 816 static void padata_sysfs_release(struct kobject *kobj) 817 { 818 struct padata_instance *pinst = kobj2pinst(kobj); 819 __padata_free(pinst); 820 } 821 822 struct padata_sysfs_entry { 823 struct attribute attr; 824 ssize_t (*show)(struct padata_instance *, struct attribute *, char *); 825 ssize_t (*store)(struct padata_instance *, struct attribute *, 826 const char *, size_t); 827 }; 828 829 static ssize_t show_cpumask(struct padata_instance *pinst, 830 struct attribute *attr, char *buf) 831 { 832 struct cpumask *cpumask; 833 ssize_t len; 834 835 mutex_lock(&pinst->lock); 836 if (!strcmp(attr->name, "serial_cpumask")) 837 cpumask = pinst->cpumask.cbcpu; 838 else 839 cpumask = pinst->cpumask.pcpu; 840 841 len = snprintf(buf, PAGE_SIZE, "%*pb\n", 842 nr_cpu_ids, cpumask_bits(cpumask)); 843 mutex_unlock(&pinst->lock); 844 return len < PAGE_SIZE ? len : -EINVAL; 845 } 846 847 static ssize_t store_cpumask(struct padata_instance *pinst, 848 struct attribute *attr, 849 const char *buf, size_t count) 850 { 851 cpumask_var_t new_cpumask; 852 ssize_t ret; 853 int mask_type; 854 855 if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL)) 856 return -ENOMEM; 857 858 ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask), 859 nr_cpumask_bits); 860 if (ret < 0) 861 goto out; 862 863 mask_type = !strcmp(attr->name, "serial_cpumask") ? 864 PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL; 865 ret = padata_set_cpumask(pinst, mask_type, new_cpumask); 866 if (!ret) 867 ret = count; 868 869 out: 870 free_cpumask_var(new_cpumask); 871 return ret; 872 } 873 874 #define PADATA_ATTR_RW(_name, _show_name, _store_name) \ 875 static struct padata_sysfs_entry _name##_attr = \ 876 __ATTR(_name, 0644, _show_name, _store_name) 877 #define PADATA_ATTR_RO(_name, _show_name) \ 878 static struct padata_sysfs_entry _name##_attr = \ 879 __ATTR(_name, 0400, _show_name, NULL) 880 881 PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask); 882 PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask); 883 884 /* 885 * Padata sysfs provides the following objects: 886 * serial_cpumask [RW] - cpumask for serial workers 887 * parallel_cpumask [RW] - cpumask for parallel workers 888 */ 889 static struct attribute *padata_default_attrs[] = { 890 &serial_cpumask_attr.attr, 891 ¶llel_cpumask_attr.attr, 892 NULL, 893 }; 894 895 static ssize_t padata_sysfs_show(struct kobject *kobj, 896 struct attribute *attr, char *buf) 897 { 898 struct padata_instance *pinst; 899 struct padata_sysfs_entry *pentry; 900 ssize_t ret = -EIO; 901 902 pinst = kobj2pinst(kobj); 903 pentry = attr2pentry(attr); 904 if (pentry->show) 905 ret = pentry->show(pinst, attr, buf); 906 907 return ret; 908 } 909 910 static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr, 911 const char *buf, size_t count) 912 { 913 struct padata_instance *pinst; 914 struct padata_sysfs_entry *pentry; 915 ssize_t ret = -EIO; 916 917 pinst = kobj2pinst(kobj); 918 pentry = attr2pentry(attr); 919 if (pentry->show) 920 ret = pentry->store(pinst, attr, buf, count); 921 922 return ret; 923 } 924 925 static const struct sysfs_ops padata_sysfs_ops = { 926 .show = padata_sysfs_show, 927 .store = padata_sysfs_store, 928 }; 929 930 static struct kobj_type padata_attr_type = { 931 .sysfs_ops = &padata_sysfs_ops, 932 .default_attrs = padata_default_attrs, 933 .release = padata_sysfs_release, 934 }; 935 936 /** 937 * padata_alloc - allocate and initialize a padata instance and specify 938 * cpumasks for serial and parallel workers. 939 * 940 * @wq: workqueue to use for the allocated padata instance 941 * @pcpumask: cpumask that will be used for padata parallelization 942 * @cbcpumask: cpumask that will be used for padata serialization 943 * 944 * Must be called from a cpus_read_lock() protected region 945 */ 946 static struct padata_instance *padata_alloc(struct workqueue_struct *wq, 947 const struct cpumask *pcpumask, 948 const struct cpumask *cbcpumask) 949 { 950 struct padata_instance *pinst; 951 struct parallel_data *pd = NULL; 952 953 pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL); 954 if (!pinst) 955 goto err; 956 957 if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL)) 958 goto err_free_inst; 959 if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) { 960 free_cpumask_var(pinst->cpumask.pcpu); 961 goto err_free_inst; 962 } 963 if (!padata_validate_cpumask(pinst, pcpumask) || 964 !padata_validate_cpumask(pinst, cbcpumask)) 965 goto err_free_masks; 966 967 pd = padata_alloc_pd(pinst, pcpumask, cbcpumask); 968 if (!pd) 969 goto err_free_masks; 970 971 rcu_assign_pointer(pinst->pd, pd); 972 973 pinst->wq = wq; 974 975 cpumask_copy(pinst->cpumask.pcpu, pcpumask); 976 cpumask_copy(pinst->cpumask.cbcpu, cbcpumask); 977 978 pinst->flags = 0; 979 980 BLOCKING_INIT_NOTIFIER_HEAD(&pinst->cpumask_change_notifier); 981 kobject_init(&pinst->kobj, &padata_attr_type); 982 mutex_init(&pinst->lock); 983 984 #ifdef CONFIG_HOTPLUG_CPU 985 cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node); 986 #endif 987 return pinst; 988 989 err_free_masks: 990 free_cpumask_var(pinst->cpumask.pcpu); 991 free_cpumask_var(pinst->cpumask.cbcpu); 992 err_free_inst: 993 kfree(pinst); 994 err: 995 return NULL; 996 } 997 998 /** 999 * padata_alloc_possible - Allocate and initialize padata instance. 1000 * Use the cpu_possible_mask for serial and 1001 * parallel workers. 1002 * 1003 * @wq: workqueue to use for the allocated padata instance 1004 * 1005 * Must be called from a cpus_read_lock() protected region 1006 */ 1007 struct padata_instance *padata_alloc_possible(struct workqueue_struct *wq) 1008 { 1009 lockdep_assert_cpus_held(); 1010 return padata_alloc(wq, cpu_possible_mask, cpu_possible_mask); 1011 } 1012 EXPORT_SYMBOL(padata_alloc_possible); 1013 1014 /** 1015 * padata_free - free a padata instance 1016 * 1017 * @padata_inst: padata instance to free 1018 */ 1019 void padata_free(struct padata_instance *pinst) 1020 { 1021 kobject_put(&pinst->kobj); 1022 } 1023 EXPORT_SYMBOL(padata_free); 1024 1025 #ifdef CONFIG_HOTPLUG_CPU 1026 1027 static __init int padata_driver_init(void) 1028 { 1029 int ret; 1030 1031 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online", 1032 padata_cpu_online, 1033 padata_cpu_prep_down); 1034 if (ret < 0) 1035 return ret; 1036 hp_online = ret; 1037 return 0; 1038 } 1039 module_init(padata_driver_init); 1040 1041 static __exit void padata_driver_exit(void) 1042 { 1043 cpuhp_remove_multi_state(hp_online); 1044 } 1045 module_exit(padata_driver_exit); 1046 #endif 1047