| 1 | /* |
| 2 | * Copyright (C) 2002 Sistina Software (UK) Limited. |
| 3 | * Copyright (C) 2006 Red Hat GmbH |
| 4 | * |
| 5 | * This file is released under the GPL. |
| 6 | * |
| 7 | * Kcopyd provides a simple interface for copying an area of one |
| 8 | * block-device to one or more other block-devices, with an asynchronous |
| 9 | * completion notification. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/types.h> |
| 13 | #include <linux/atomic.h> |
| 14 | #include <linux/blkdev.h> |
| 15 | #include <linux/fs.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/list.h> |
| 18 | #include <linux/mempool.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/pagemap.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/vmalloc.h> |
| 23 | #include <linux/workqueue.h> |
| 24 | #include <linux/mutex.h> |
| 25 | #include <linux/device-mapper.h> |
| 26 | #include <linux/dm-kcopyd.h> |
| 27 | |
| 28 | #include "dm.h" |
| 29 | |
| 30 | #define SUB_JOB_SIZE 128 |
| 31 | #define SPLIT_COUNT 8 |
| 32 | #define MIN_JOBS 8 |
| 33 | #define RESERVE_PAGES (DIV_ROUND_UP(SUB_JOB_SIZE << SECTOR_SHIFT, PAGE_SIZE)) |
| 34 | |
| 35 | /*----------------------------------------------------------------- |
| 36 | * Each kcopyd client has its own little pool of preallocated |
| 37 | * pages for kcopyd io. |
| 38 | *---------------------------------------------------------------*/ |
| 39 | struct dm_kcopyd_client { |
| 40 | struct page_list *pages; |
| 41 | unsigned nr_reserved_pages; |
| 42 | unsigned nr_free_pages; |
| 43 | |
| 44 | struct dm_io_client *io_client; |
| 45 | |
| 46 | wait_queue_head_t destroyq; |
| 47 | atomic_t nr_jobs; |
| 48 | |
| 49 | mempool_t *job_pool; |
| 50 | |
| 51 | struct workqueue_struct *kcopyd_wq; |
| 52 | struct work_struct kcopyd_work; |
| 53 | |
| 54 | /* |
| 55 | * We maintain three lists of jobs: |
| 56 | * |
| 57 | * i) jobs waiting for pages |
| 58 | * ii) jobs that have pages, and are waiting for the io to be issued. |
| 59 | * iii) jobs that have completed. |
| 60 | * |
| 61 | * All three of these are protected by job_lock. |
| 62 | */ |
| 63 | spinlock_t job_lock; |
| 64 | struct list_head complete_jobs; |
| 65 | struct list_head io_jobs; |
| 66 | struct list_head pages_jobs; |
| 67 | }; |
| 68 | |
| 69 | static struct page_list zero_page_list; |
| 70 | |
| 71 | static void wake(struct dm_kcopyd_client *kc) |
| 72 | { |
| 73 | queue_work(kc->kcopyd_wq, &kc->kcopyd_work); |
| 74 | } |
| 75 | |
| 76 | /* |
| 77 | * Obtain one page for the use of kcopyd. |
| 78 | */ |
| 79 | static struct page_list *alloc_pl(gfp_t gfp) |
| 80 | { |
| 81 | struct page_list *pl; |
| 82 | |
| 83 | pl = kmalloc(sizeof(*pl), gfp); |
| 84 | if (!pl) |
| 85 | return NULL; |
| 86 | |
| 87 | pl->page = alloc_page(gfp); |
| 88 | if (!pl->page) { |
| 89 | kfree(pl); |
| 90 | return NULL; |
| 91 | } |
| 92 | |
| 93 | return pl; |
| 94 | } |
| 95 | |
| 96 | static void free_pl(struct page_list *pl) |
| 97 | { |
| 98 | __free_page(pl->page); |
| 99 | kfree(pl); |
| 100 | } |
| 101 | |
| 102 | /* |
| 103 | * Add the provided pages to a client's free page list, releasing |
| 104 | * back to the system any beyond the reserved_pages limit. |
| 105 | */ |
| 106 | static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl) |
| 107 | { |
| 108 | struct page_list *next; |
| 109 | |
| 110 | do { |
| 111 | next = pl->next; |
| 112 | |
| 113 | if (kc->nr_free_pages >= kc->nr_reserved_pages) |
| 114 | free_pl(pl); |
| 115 | else { |
| 116 | pl->next = kc->pages; |
| 117 | kc->pages = pl; |
| 118 | kc->nr_free_pages++; |
| 119 | } |
| 120 | |
| 121 | pl = next; |
| 122 | } while (pl); |
| 123 | } |
| 124 | |
| 125 | static int kcopyd_get_pages(struct dm_kcopyd_client *kc, |
| 126 | unsigned int nr, struct page_list **pages) |
| 127 | { |
| 128 | struct page_list *pl; |
| 129 | |
| 130 | *pages = NULL; |
| 131 | |
| 132 | do { |
| 133 | pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY); |
| 134 | if (unlikely(!pl)) { |
| 135 | /* Use reserved pages */ |
| 136 | pl = kc->pages; |
| 137 | if (unlikely(!pl)) |
| 138 | goto out_of_memory; |
| 139 | kc->pages = pl->next; |
| 140 | kc->nr_free_pages--; |
| 141 | } |
| 142 | pl->next = *pages; |
| 143 | *pages = pl; |
| 144 | } while (--nr); |
| 145 | |
| 146 | return 0; |
| 147 | |
| 148 | out_of_memory: |
| 149 | if (*pages) |
| 150 | kcopyd_put_pages(kc, *pages); |
| 151 | return -ENOMEM; |
| 152 | } |
| 153 | |
| 154 | /* |
| 155 | * These three functions resize the page pool. |
| 156 | */ |
| 157 | static void drop_pages(struct page_list *pl) |
| 158 | { |
| 159 | struct page_list *next; |
| 160 | |
| 161 | while (pl) { |
| 162 | next = pl->next; |
| 163 | free_pl(pl); |
| 164 | pl = next; |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | /* |
| 169 | * Allocate and reserve nr_pages for the use of a specific client. |
| 170 | */ |
| 171 | static int client_reserve_pages(struct dm_kcopyd_client *kc, unsigned nr_pages) |
| 172 | { |
| 173 | unsigned i; |
| 174 | struct page_list *pl = NULL, *next; |
| 175 | |
| 176 | for (i = 0; i < nr_pages; i++) { |
| 177 | next = alloc_pl(GFP_KERNEL); |
| 178 | if (!next) { |
| 179 | if (pl) |
| 180 | drop_pages(pl); |
| 181 | return -ENOMEM; |
| 182 | } |
| 183 | next->next = pl; |
| 184 | pl = next; |
| 185 | } |
| 186 | |
| 187 | kc->nr_reserved_pages += nr_pages; |
| 188 | kcopyd_put_pages(kc, pl); |
| 189 | |
| 190 | return 0; |
| 191 | } |
| 192 | |
| 193 | static void client_free_pages(struct dm_kcopyd_client *kc) |
| 194 | { |
| 195 | BUG_ON(kc->nr_free_pages != kc->nr_reserved_pages); |
| 196 | drop_pages(kc->pages); |
| 197 | kc->pages = NULL; |
| 198 | kc->nr_free_pages = kc->nr_reserved_pages = 0; |
| 199 | } |
| 200 | |
| 201 | /*----------------------------------------------------------------- |
| 202 | * kcopyd_jobs need to be allocated by the *clients* of kcopyd, |
| 203 | * for this reason we use a mempool to prevent the client from |
| 204 | * ever having to do io (which could cause a deadlock). |
| 205 | *---------------------------------------------------------------*/ |
| 206 | struct kcopyd_job { |
| 207 | struct dm_kcopyd_client *kc; |
| 208 | struct list_head list; |
| 209 | unsigned long flags; |
| 210 | |
| 211 | /* |
| 212 | * Error state of the job. |
| 213 | */ |
| 214 | int read_err; |
| 215 | unsigned long write_err; |
| 216 | |
| 217 | /* |
| 218 | * Either READ or WRITE |
| 219 | */ |
| 220 | int rw; |
| 221 | struct dm_io_region source; |
| 222 | |
| 223 | /* |
| 224 | * The destinations for the transfer. |
| 225 | */ |
| 226 | unsigned int num_dests; |
| 227 | struct dm_io_region dests[DM_KCOPYD_MAX_REGIONS]; |
| 228 | |
| 229 | struct page_list *pages; |
| 230 | |
| 231 | /* |
| 232 | * Set this to ensure you are notified when the job has |
| 233 | * completed. 'context' is for callback to use. |
| 234 | */ |
| 235 | dm_kcopyd_notify_fn fn; |
| 236 | void *context; |
| 237 | |
| 238 | /* |
| 239 | * These fields are only used if the job has been split |
| 240 | * into more manageable parts. |
| 241 | */ |
| 242 | struct mutex lock; |
| 243 | atomic_t sub_jobs; |
| 244 | sector_t progress; |
| 245 | |
| 246 | struct kcopyd_job *master_job; |
| 247 | }; |
| 248 | |
| 249 | static struct kmem_cache *_job_cache; |
| 250 | |
| 251 | int __init dm_kcopyd_init(void) |
| 252 | { |
| 253 | _job_cache = kmem_cache_create("kcopyd_job", |
| 254 | sizeof(struct kcopyd_job) * (SPLIT_COUNT + 1), |
| 255 | __alignof__(struct kcopyd_job), 0, NULL); |
| 256 | if (!_job_cache) |
| 257 | return -ENOMEM; |
| 258 | |
| 259 | zero_page_list.next = &zero_page_list; |
| 260 | zero_page_list.page = ZERO_PAGE(0); |
| 261 | |
| 262 | return 0; |
| 263 | } |
| 264 | |
| 265 | void dm_kcopyd_exit(void) |
| 266 | { |
| 267 | kmem_cache_destroy(_job_cache); |
| 268 | _job_cache = NULL; |
| 269 | } |
| 270 | |
| 271 | /* |
| 272 | * Functions to push and pop a job onto the head of a given job |
| 273 | * list. |
| 274 | */ |
| 275 | static struct kcopyd_job *pop(struct list_head *jobs, |
| 276 | struct dm_kcopyd_client *kc) |
| 277 | { |
| 278 | struct kcopyd_job *job = NULL; |
| 279 | unsigned long flags; |
| 280 | |
| 281 | spin_lock_irqsave(&kc->job_lock, flags); |
| 282 | |
| 283 | if (!list_empty(jobs)) { |
| 284 | job = list_entry(jobs->next, struct kcopyd_job, list); |
| 285 | list_del(&job->list); |
| 286 | } |
| 287 | spin_unlock_irqrestore(&kc->job_lock, flags); |
| 288 | |
| 289 | return job; |
| 290 | } |
| 291 | |
| 292 | static void push(struct list_head *jobs, struct kcopyd_job *job) |
| 293 | { |
| 294 | unsigned long flags; |
| 295 | struct dm_kcopyd_client *kc = job->kc; |
| 296 | |
| 297 | spin_lock_irqsave(&kc->job_lock, flags); |
| 298 | list_add_tail(&job->list, jobs); |
| 299 | spin_unlock_irqrestore(&kc->job_lock, flags); |
| 300 | } |
| 301 | |
| 302 | |
| 303 | static void push_head(struct list_head *jobs, struct kcopyd_job *job) |
| 304 | { |
| 305 | unsigned long flags; |
| 306 | struct dm_kcopyd_client *kc = job->kc; |
| 307 | |
| 308 | spin_lock_irqsave(&kc->job_lock, flags); |
| 309 | list_add(&job->list, jobs); |
| 310 | spin_unlock_irqrestore(&kc->job_lock, flags); |
| 311 | } |
| 312 | |
| 313 | /* |
| 314 | * These three functions process 1 item from the corresponding |
| 315 | * job list. |
| 316 | * |
| 317 | * They return: |
| 318 | * < 0: error |
| 319 | * 0: success |
| 320 | * > 0: can't process yet. |
| 321 | */ |
| 322 | static int run_complete_job(struct kcopyd_job *job) |
| 323 | { |
| 324 | void *context = job->context; |
| 325 | int read_err = job->read_err; |
| 326 | unsigned long write_err = job->write_err; |
| 327 | dm_kcopyd_notify_fn fn = job->fn; |
| 328 | struct dm_kcopyd_client *kc = job->kc; |
| 329 | |
| 330 | if (job->pages && job->pages != &zero_page_list) |
| 331 | kcopyd_put_pages(kc, job->pages); |
| 332 | /* |
| 333 | * If this is the master job, the sub jobs have already |
| 334 | * completed so we can free everything. |
| 335 | */ |
| 336 | if (job->master_job == job) |
| 337 | mempool_free(job, kc->job_pool); |
| 338 | fn(read_err, write_err, context); |
| 339 | |
| 340 | if (atomic_dec_and_test(&kc->nr_jobs)) |
| 341 | wake_up(&kc->destroyq); |
| 342 | |
| 343 | return 0; |
| 344 | } |
| 345 | |
| 346 | static void complete_io(unsigned long error, void *context) |
| 347 | { |
| 348 | struct kcopyd_job *job = (struct kcopyd_job *) context; |
| 349 | struct dm_kcopyd_client *kc = job->kc; |
| 350 | |
| 351 | if (error) { |
| 352 | if (job->rw == WRITE) |
| 353 | job->write_err |= error; |
| 354 | else |
| 355 | job->read_err = 1; |
| 356 | |
| 357 | if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { |
| 358 | push(&kc->complete_jobs, job); |
| 359 | wake(kc); |
| 360 | return; |
| 361 | } |
| 362 | } |
| 363 | |
| 364 | if (job->rw == WRITE) |
| 365 | push(&kc->complete_jobs, job); |
| 366 | |
| 367 | else { |
| 368 | job->rw = WRITE; |
| 369 | push(&kc->io_jobs, job); |
| 370 | } |
| 371 | |
| 372 | wake(kc); |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * Request io on as many buffer heads as we can currently get for |
| 377 | * a particular job. |
| 378 | */ |
| 379 | static int run_io_job(struct kcopyd_job *job) |
| 380 | { |
| 381 | int r; |
| 382 | struct dm_io_request io_req = { |
| 383 | .bi_rw = job->rw, |
| 384 | .mem.type = DM_IO_PAGE_LIST, |
| 385 | .mem.ptr.pl = job->pages, |
| 386 | .mem.offset = 0, |
| 387 | .notify.fn = complete_io, |
| 388 | .notify.context = job, |
| 389 | .client = job->kc->io_client, |
| 390 | }; |
| 391 | |
| 392 | if (job->rw == READ) |
| 393 | r = dm_io(&io_req, 1, &job->source, NULL); |
| 394 | else |
| 395 | r = dm_io(&io_req, job->num_dests, job->dests, NULL); |
| 396 | |
| 397 | return r; |
| 398 | } |
| 399 | |
| 400 | static int run_pages_job(struct kcopyd_job *job) |
| 401 | { |
| 402 | int r; |
| 403 | unsigned nr_pages = dm_div_up(job->dests[0].count, PAGE_SIZE >> 9); |
| 404 | |
| 405 | r = kcopyd_get_pages(job->kc, nr_pages, &job->pages); |
| 406 | if (!r) { |
| 407 | /* this job is ready for io */ |
| 408 | push(&job->kc->io_jobs, job); |
| 409 | return 0; |
| 410 | } |
| 411 | |
| 412 | if (r == -ENOMEM) |
| 413 | /* can't complete now */ |
| 414 | return 1; |
| 415 | |
| 416 | return r; |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * Run through a list for as long as possible. Returns the count |
| 421 | * of successful jobs. |
| 422 | */ |
| 423 | static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc, |
| 424 | int (*fn) (struct kcopyd_job *)) |
| 425 | { |
| 426 | struct kcopyd_job *job; |
| 427 | int r, count = 0; |
| 428 | |
| 429 | while ((job = pop(jobs, kc))) { |
| 430 | |
| 431 | r = fn(job); |
| 432 | |
| 433 | if (r < 0) { |
| 434 | /* error this rogue job */ |
| 435 | if (job->rw == WRITE) |
| 436 | job->write_err = (unsigned long) -1L; |
| 437 | else |
| 438 | job->read_err = 1; |
| 439 | push(&kc->complete_jobs, job); |
| 440 | break; |
| 441 | } |
| 442 | |
| 443 | if (r > 0) { |
| 444 | /* |
| 445 | * We couldn't service this job ATM, so |
| 446 | * push this job back onto the list. |
| 447 | */ |
| 448 | push_head(jobs, job); |
| 449 | break; |
| 450 | } |
| 451 | |
| 452 | count++; |
| 453 | } |
| 454 | |
| 455 | return count; |
| 456 | } |
| 457 | |
| 458 | /* |
| 459 | * kcopyd does this every time it's woken up. |
| 460 | */ |
| 461 | static void do_work(struct work_struct *work) |
| 462 | { |
| 463 | struct dm_kcopyd_client *kc = container_of(work, |
| 464 | struct dm_kcopyd_client, kcopyd_work); |
| 465 | struct blk_plug plug; |
| 466 | |
| 467 | /* |
| 468 | * The order that these are called is *very* important. |
| 469 | * complete jobs can free some pages for pages jobs. |
| 470 | * Pages jobs when successful will jump onto the io jobs |
| 471 | * list. io jobs call wake when they complete and it all |
| 472 | * starts again. |
| 473 | */ |
| 474 | blk_start_plug(&plug); |
| 475 | process_jobs(&kc->complete_jobs, kc, run_complete_job); |
| 476 | process_jobs(&kc->pages_jobs, kc, run_pages_job); |
| 477 | process_jobs(&kc->io_jobs, kc, run_io_job); |
| 478 | blk_finish_plug(&plug); |
| 479 | } |
| 480 | |
| 481 | /* |
| 482 | * If we are copying a small region we just dispatch a single job |
| 483 | * to do the copy, otherwise the io has to be split up into many |
| 484 | * jobs. |
| 485 | */ |
| 486 | static void dispatch_job(struct kcopyd_job *job) |
| 487 | { |
| 488 | struct dm_kcopyd_client *kc = job->kc; |
| 489 | atomic_inc(&kc->nr_jobs); |
| 490 | if (unlikely(!job->source.count)) |
| 491 | push(&kc->complete_jobs, job); |
| 492 | else if (job->pages == &zero_page_list) |
| 493 | push(&kc->io_jobs, job); |
| 494 | else |
| 495 | push(&kc->pages_jobs, job); |
| 496 | wake(kc); |
| 497 | } |
| 498 | |
| 499 | static void segment_complete(int read_err, unsigned long write_err, |
| 500 | void *context) |
| 501 | { |
| 502 | /* FIXME: tidy this function */ |
| 503 | sector_t progress = 0; |
| 504 | sector_t count = 0; |
| 505 | struct kcopyd_job *sub_job = (struct kcopyd_job *) context; |
| 506 | struct kcopyd_job *job = sub_job->master_job; |
| 507 | struct dm_kcopyd_client *kc = job->kc; |
| 508 | |
| 509 | mutex_lock(&job->lock); |
| 510 | |
| 511 | /* update the error */ |
| 512 | if (read_err) |
| 513 | job->read_err = 1; |
| 514 | |
| 515 | if (write_err) |
| 516 | job->write_err |= write_err; |
| 517 | |
| 518 | /* |
| 519 | * Only dispatch more work if there hasn't been an error. |
| 520 | */ |
| 521 | if ((!job->read_err && !job->write_err) || |
| 522 | test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { |
| 523 | /* get the next chunk of work */ |
| 524 | progress = job->progress; |
| 525 | count = job->source.count - progress; |
| 526 | if (count) { |
| 527 | if (count > SUB_JOB_SIZE) |
| 528 | count = SUB_JOB_SIZE; |
| 529 | |
| 530 | job->progress += count; |
| 531 | } |
| 532 | } |
| 533 | mutex_unlock(&job->lock); |
| 534 | |
| 535 | if (count) { |
| 536 | int i; |
| 537 | |
| 538 | *sub_job = *job; |
| 539 | sub_job->source.sector += progress; |
| 540 | sub_job->source.count = count; |
| 541 | |
| 542 | for (i = 0; i < job->num_dests; i++) { |
| 543 | sub_job->dests[i].sector += progress; |
| 544 | sub_job->dests[i].count = count; |
| 545 | } |
| 546 | |
| 547 | sub_job->fn = segment_complete; |
| 548 | sub_job->context = sub_job; |
| 549 | dispatch_job(sub_job); |
| 550 | |
| 551 | } else if (atomic_dec_and_test(&job->sub_jobs)) { |
| 552 | |
| 553 | /* |
| 554 | * Queue the completion callback to the kcopyd thread. |
| 555 | * |
| 556 | * Some callers assume that all the completions are called |
| 557 | * from a single thread and don't race with each other. |
| 558 | * |
| 559 | * We must not call the callback directly here because this |
| 560 | * code may not be executing in the thread. |
| 561 | */ |
| 562 | push(&kc->complete_jobs, job); |
| 563 | wake(kc); |
| 564 | } |
| 565 | } |
| 566 | |
| 567 | /* |
| 568 | * Create some sub jobs to share the work between them. |
| 569 | */ |
| 570 | static void split_job(struct kcopyd_job *master_job) |
| 571 | { |
| 572 | int i; |
| 573 | |
| 574 | atomic_inc(&master_job->kc->nr_jobs); |
| 575 | |
| 576 | atomic_set(&master_job->sub_jobs, SPLIT_COUNT); |
| 577 | for (i = 0; i < SPLIT_COUNT; i++) { |
| 578 | master_job[i + 1].master_job = master_job; |
| 579 | segment_complete(0, 0u, &master_job[i + 1]); |
| 580 | } |
| 581 | } |
| 582 | |
| 583 | int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, |
| 584 | unsigned int num_dests, struct dm_io_region *dests, |
| 585 | unsigned int flags, dm_kcopyd_notify_fn fn, void *context) |
| 586 | { |
| 587 | struct kcopyd_job *job; |
| 588 | |
| 589 | /* |
| 590 | * Allocate an array of jobs consisting of one master job |
| 591 | * followed by SPLIT_COUNT sub jobs. |
| 592 | */ |
| 593 | job = mempool_alloc(kc->job_pool, GFP_NOIO); |
| 594 | |
| 595 | /* |
| 596 | * set up for the read. |
| 597 | */ |
| 598 | job->kc = kc; |
| 599 | job->flags = flags; |
| 600 | job->read_err = 0; |
| 601 | job->write_err = 0; |
| 602 | |
| 603 | job->num_dests = num_dests; |
| 604 | memcpy(&job->dests, dests, sizeof(*dests) * num_dests); |
| 605 | |
| 606 | if (from) { |
| 607 | job->source = *from; |
| 608 | job->pages = NULL; |
| 609 | job->rw = READ; |
| 610 | } else { |
| 611 | memset(&job->source, 0, sizeof job->source); |
| 612 | job->source.count = job->dests[0].count; |
| 613 | job->pages = &zero_page_list; |
| 614 | job->rw = WRITE; |
| 615 | } |
| 616 | |
| 617 | job->fn = fn; |
| 618 | job->context = context; |
| 619 | job->master_job = job; |
| 620 | |
| 621 | if (job->source.count <= SUB_JOB_SIZE) |
| 622 | dispatch_job(job); |
| 623 | else { |
| 624 | mutex_init(&job->lock); |
| 625 | job->progress = 0; |
| 626 | split_job(job); |
| 627 | } |
| 628 | |
| 629 | return 0; |
| 630 | } |
| 631 | EXPORT_SYMBOL(dm_kcopyd_copy); |
| 632 | |
| 633 | int dm_kcopyd_zero(struct dm_kcopyd_client *kc, |
| 634 | unsigned num_dests, struct dm_io_region *dests, |
| 635 | unsigned flags, dm_kcopyd_notify_fn fn, void *context) |
| 636 | { |
| 637 | return dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context); |
| 638 | } |
| 639 | EXPORT_SYMBOL(dm_kcopyd_zero); |
| 640 | |
| 641 | void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, |
| 642 | dm_kcopyd_notify_fn fn, void *context) |
| 643 | { |
| 644 | struct kcopyd_job *job; |
| 645 | |
| 646 | job = mempool_alloc(kc->job_pool, GFP_NOIO); |
| 647 | |
| 648 | memset(job, 0, sizeof(struct kcopyd_job)); |
| 649 | job->kc = kc; |
| 650 | job->fn = fn; |
| 651 | job->context = context; |
| 652 | job->master_job = job; |
| 653 | |
| 654 | atomic_inc(&kc->nr_jobs); |
| 655 | |
| 656 | return job; |
| 657 | } |
| 658 | EXPORT_SYMBOL(dm_kcopyd_prepare_callback); |
| 659 | |
| 660 | void dm_kcopyd_do_callback(void *j, int read_err, unsigned long write_err) |
| 661 | { |
| 662 | struct kcopyd_job *job = j; |
| 663 | struct dm_kcopyd_client *kc = job->kc; |
| 664 | |
| 665 | job->read_err = read_err; |
| 666 | job->write_err = write_err; |
| 667 | |
| 668 | push(&kc->complete_jobs, job); |
| 669 | wake(kc); |
| 670 | } |
| 671 | EXPORT_SYMBOL(dm_kcopyd_do_callback); |
| 672 | |
| 673 | /* |
| 674 | * Cancels a kcopyd job, eg. someone might be deactivating a |
| 675 | * mirror. |
| 676 | */ |
| 677 | #if 0 |
| 678 | int kcopyd_cancel(struct kcopyd_job *job, int block) |
| 679 | { |
| 680 | /* FIXME: finish */ |
| 681 | return -1; |
| 682 | } |
| 683 | #endif /* 0 */ |
| 684 | |
| 685 | /*----------------------------------------------------------------- |
| 686 | * Client setup |
| 687 | *---------------------------------------------------------------*/ |
| 688 | struct dm_kcopyd_client *dm_kcopyd_client_create(void) |
| 689 | { |
| 690 | int r = -ENOMEM; |
| 691 | struct dm_kcopyd_client *kc; |
| 692 | |
| 693 | kc = kmalloc(sizeof(*kc), GFP_KERNEL); |
| 694 | if (!kc) |
| 695 | return ERR_PTR(-ENOMEM); |
| 696 | |
| 697 | spin_lock_init(&kc->job_lock); |
| 698 | INIT_LIST_HEAD(&kc->complete_jobs); |
| 699 | INIT_LIST_HEAD(&kc->io_jobs); |
| 700 | INIT_LIST_HEAD(&kc->pages_jobs); |
| 701 | |
| 702 | kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); |
| 703 | if (!kc->job_pool) |
| 704 | goto bad_slab; |
| 705 | |
| 706 | INIT_WORK(&kc->kcopyd_work, do_work); |
| 707 | kc->kcopyd_wq = alloc_workqueue("kcopyd", |
| 708 | WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0); |
| 709 | if (!kc->kcopyd_wq) |
| 710 | goto bad_workqueue; |
| 711 | |
| 712 | kc->pages = NULL; |
| 713 | kc->nr_reserved_pages = kc->nr_free_pages = 0; |
| 714 | r = client_reserve_pages(kc, RESERVE_PAGES); |
| 715 | if (r) |
| 716 | goto bad_client_pages; |
| 717 | |
| 718 | kc->io_client = dm_io_client_create(); |
| 719 | if (IS_ERR(kc->io_client)) { |
| 720 | r = PTR_ERR(kc->io_client); |
| 721 | goto bad_io_client; |
| 722 | } |
| 723 | |
| 724 | init_waitqueue_head(&kc->destroyq); |
| 725 | atomic_set(&kc->nr_jobs, 0); |
| 726 | |
| 727 | return kc; |
| 728 | |
| 729 | bad_io_client: |
| 730 | client_free_pages(kc); |
| 731 | bad_client_pages: |
| 732 | destroy_workqueue(kc->kcopyd_wq); |
| 733 | bad_workqueue: |
| 734 | mempool_destroy(kc->job_pool); |
| 735 | bad_slab: |
| 736 | kfree(kc); |
| 737 | |
| 738 | return ERR_PTR(r); |
| 739 | } |
| 740 | EXPORT_SYMBOL(dm_kcopyd_client_create); |
| 741 | |
| 742 | void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc) |
| 743 | { |
| 744 | /* Wait for completion of all jobs submitted by this client. */ |
| 745 | wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs)); |
| 746 | |
| 747 | BUG_ON(!list_empty(&kc->complete_jobs)); |
| 748 | BUG_ON(!list_empty(&kc->io_jobs)); |
| 749 | BUG_ON(!list_empty(&kc->pages_jobs)); |
| 750 | destroy_workqueue(kc->kcopyd_wq); |
| 751 | dm_io_client_destroy(kc->io_client); |
| 752 | client_free_pages(kc); |
| 753 | mempool_destroy(kc->job_pool); |
| 754 | kfree(kc); |
| 755 | } |
| 756 | EXPORT_SYMBOL(dm_kcopyd_client_destroy); |