Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2002 Sistina Software (UK) Limited. |
| 3 | * |
| 4 | * This file is released under the GPL. |
| 5 | * |
| 6 | * Kcopyd provides a simple interface for copying an area of one |
| 7 | * block-device to one or more other block-devices, with an asynchronous |
| 8 | * completion notification. |
| 9 | */ |
| 10 | |
Alan Cox | 715b49e | 2006-01-18 17:44:07 -0800 | [diff] [blame] | 11 | #include <asm/types.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <asm/atomic.h> |
| 13 | |
| 14 | #include <linux/blkdev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Arjan van de Ven | 48c9c27 | 2006-03-27 01:18:20 -0800 | [diff] [blame] | 24 | #include <linux/mutex.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | |
| 26 | #include "kcopyd.h" |
| 27 | |
| 28 | static struct workqueue_struct *_kcopyd_wq; |
| 29 | static struct work_struct _kcopyd_work; |
| 30 | |
| 31 | static inline void wake(void) |
| 32 | { |
| 33 | queue_work(_kcopyd_wq, &_kcopyd_work); |
| 34 | } |
| 35 | |
| 36 | /*----------------------------------------------------------------- |
| 37 | * Each kcopyd client has its own little pool of preallocated |
| 38 | * pages for kcopyd io. |
| 39 | *---------------------------------------------------------------*/ |
| 40 | struct kcopyd_client { |
| 41 | struct list_head list; |
| 42 | |
| 43 | spinlock_t lock; |
| 44 | struct page_list *pages; |
| 45 | unsigned int nr_pages; |
| 46 | unsigned int nr_free_pages; |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 47 | |
| 48 | wait_queue_head_t destroyq; |
| 49 | atomic_t nr_jobs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | }; |
| 51 | |
| 52 | static struct page_list *alloc_pl(void) |
| 53 | { |
| 54 | struct page_list *pl; |
| 55 | |
| 56 | pl = kmalloc(sizeof(*pl), GFP_KERNEL); |
| 57 | if (!pl) |
| 58 | return NULL; |
| 59 | |
| 60 | pl->page = alloc_page(GFP_KERNEL); |
| 61 | if (!pl->page) { |
| 62 | kfree(pl); |
| 63 | return NULL; |
| 64 | } |
| 65 | |
| 66 | return pl; |
| 67 | } |
| 68 | |
| 69 | static void free_pl(struct page_list *pl) |
| 70 | { |
| 71 | __free_page(pl->page); |
| 72 | kfree(pl); |
| 73 | } |
| 74 | |
| 75 | static int kcopyd_get_pages(struct kcopyd_client *kc, |
| 76 | unsigned int nr, struct page_list **pages) |
| 77 | { |
| 78 | struct page_list *pl; |
| 79 | |
| 80 | spin_lock(&kc->lock); |
| 81 | if (kc->nr_free_pages < nr) { |
| 82 | spin_unlock(&kc->lock); |
| 83 | return -ENOMEM; |
| 84 | } |
| 85 | |
| 86 | kc->nr_free_pages -= nr; |
| 87 | for (*pages = pl = kc->pages; --nr; pl = pl->next) |
| 88 | ; |
| 89 | |
| 90 | kc->pages = pl->next; |
| 91 | pl->next = NULL; |
| 92 | |
| 93 | spin_unlock(&kc->lock); |
| 94 | |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | static void kcopyd_put_pages(struct kcopyd_client *kc, struct page_list *pl) |
| 99 | { |
| 100 | struct page_list *cursor; |
| 101 | |
| 102 | spin_lock(&kc->lock); |
| 103 | for (cursor = pl; cursor->next; cursor = cursor->next) |
| 104 | kc->nr_free_pages++; |
| 105 | |
| 106 | kc->nr_free_pages++; |
| 107 | cursor->next = kc->pages; |
| 108 | kc->pages = pl; |
| 109 | spin_unlock(&kc->lock); |
| 110 | } |
| 111 | |
| 112 | /* |
| 113 | * These three functions resize the page pool. |
| 114 | */ |
| 115 | static void drop_pages(struct page_list *pl) |
| 116 | { |
| 117 | struct page_list *next; |
| 118 | |
| 119 | while (pl) { |
| 120 | next = pl->next; |
| 121 | free_pl(pl); |
| 122 | pl = next; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | static int client_alloc_pages(struct kcopyd_client *kc, unsigned int nr) |
| 127 | { |
| 128 | unsigned int i; |
| 129 | struct page_list *pl = NULL, *next; |
| 130 | |
| 131 | for (i = 0; i < nr; i++) { |
| 132 | next = alloc_pl(); |
| 133 | if (!next) { |
| 134 | if (pl) |
| 135 | drop_pages(pl); |
| 136 | return -ENOMEM; |
| 137 | } |
| 138 | next->next = pl; |
| 139 | pl = next; |
| 140 | } |
| 141 | |
| 142 | kcopyd_put_pages(kc, pl); |
| 143 | kc->nr_pages += nr; |
| 144 | return 0; |
| 145 | } |
| 146 | |
| 147 | static void client_free_pages(struct kcopyd_client *kc) |
| 148 | { |
| 149 | BUG_ON(kc->nr_free_pages != kc->nr_pages); |
| 150 | drop_pages(kc->pages); |
| 151 | kc->pages = NULL; |
| 152 | kc->nr_free_pages = kc->nr_pages = 0; |
| 153 | } |
| 154 | |
| 155 | /*----------------------------------------------------------------- |
| 156 | * kcopyd_jobs need to be allocated by the *clients* of kcopyd, |
| 157 | * for this reason we use a mempool to prevent the client from |
| 158 | * ever having to do io (which could cause a deadlock). |
| 159 | *---------------------------------------------------------------*/ |
| 160 | struct kcopyd_job { |
| 161 | struct kcopyd_client *kc; |
| 162 | struct list_head list; |
| 163 | unsigned long flags; |
| 164 | |
| 165 | /* |
| 166 | * Error state of the job. |
| 167 | */ |
| 168 | int read_err; |
| 169 | unsigned int write_err; |
| 170 | |
| 171 | /* |
| 172 | * Either READ or WRITE |
| 173 | */ |
| 174 | int rw; |
| 175 | struct io_region source; |
| 176 | |
| 177 | /* |
| 178 | * The destinations for the transfer. |
| 179 | */ |
| 180 | unsigned int num_dests; |
| 181 | struct io_region dests[KCOPYD_MAX_REGIONS]; |
| 182 | |
| 183 | sector_t offset; |
| 184 | unsigned int nr_pages; |
| 185 | struct page_list *pages; |
| 186 | |
| 187 | /* |
| 188 | * Set this to ensure you are notified when the job has |
| 189 | * completed. 'context' is for callback to use. |
| 190 | */ |
| 191 | kcopyd_notify_fn fn; |
| 192 | void *context; |
| 193 | |
| 194 | /* |
| 195 | * These fields are only used if the job has been split |
| 196 | * into more manageable parts. |
| 197 | */ |
| 198 | struct semaphore lock; |
| 199 | atomic_t sub_jobs; |
| 200 | sector_t progress; |
| 201 | }; |
| 202 | |
| 203 | /* FIXME: this should scale with the number of pages */ |
| 204 | #define MIN_JOBS 512 |
| 205 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 206 | static struct kmem_cache *_job_cache; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | static mempool_t *_job_pool; |
| 208 | |
| 209 | /* |
| 210 | * We maintain three lists of jobs: |
| 211 | * |
| 212 | * i) jobs waiting for pages |
| 213 | * ii) jobs that have pages, and are waiting for the io to be issued. |
| 214 | * iii) jobs that have completed. |
| 215 | * |
| 216 | * All three of these are protected by job_lock. |
| 217 | */ |
| 218 | static DEFINE_SPINLOCK(_job_lock); |
| 219 | |
| 220 | static LIST_HEAD(_complete_jobs); |
| 221 | static LIST_HEAD(_io_jobs); |
| 222 | static LIST_HEAD(_pages_jobs); |
| 223 | |
| 224 | static int jobs_init(void) |
| 225 | { |
| 226 | _job_cache = kmem_cache_create("kcopyd-jobs", |
| 227 | sizeof(struct kcopyd_job), |
| 228 | __alignof__(struct kcopyd_job), |
| 229 | 0, NULL, NULL); |
| 230 | if (!_job_cache) |
| 231 | return -ENOMEM; |
| 232 | |
Matthew Dobson | 93d2341 | 2006-03-26 01:37:50 -0800 | [diff] [blame] | 233 | _job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | if (!_job_pool) { |
| 235 | kmem_cache_destroy(_job_cache); |
| 236 | return -ENOMEM; |
| 237 | } |
| 238 | |
| 239 | return 0; |
| 240 | } |
| 241 | |
| 242 | static void jobs_exit(void) |
| 243 | { |
| 244 | BUG_ON(!list_empty(&_complete_jobs)); |
| 245 | BUG_ON(!list_empty(&_io_jobs)); |
| 246 | BUG_ON(!list_empty(&_pages_jobs)); |
| 247 | |
| 248 | mempool_destroy(_job_pool); |
| 249 | kmem_cache_destroy(_job_cache); |
| 250 | _job_pool = NULL; |
| 251 | _job_cache = NULL; |
| 252 | } |
| 253 | |
| 254 | /* |
| 255 | * Functions to push and pop a job onto the head of a given job |
| 256 | * list. |
| 257 | */ |
| 258 | static inline struct kcopyd_job *pop(struct list_head *jobs) |
| 259 | { |
| 260 | struct kcopyd_job *job = NULL; |
| 261 | unsigned long flags; |
| 262 | |
| 263 | spin_lock_irqsave(&_job_lock, flags); |
| 264 | |
| 265 | if (!list_empty(jobs)) { |
| 266 | job = list_entry(jobs->next, struct kcopyd_job, list); |
| 267 | list_del(&job->list); |
| 268 | } |
| 269 | spin_unlock_irqrestore(&_job_lock, flags); |
| 270 | |
| 271 | return job; |
| 272 | } |
| 273 | |
| 274 | static inline void push(struct list_head *jobs, struct kcopyd_job *job) |
| 275 | { |
| 276 | unsigned long flags; |
| 277 | |
| 278 | spin_lock_irqsave(&_job_lock, flags); |
| 279 | list_add_tail(&job->list, jobs); |
| 280 | spin_unlock_irqrestore(&_job_lock, flags); |
| 281 | } |
| 282 | |
| 283 | /* |
| 284 | * These three functions process 1 item from the corresponding |
| 285 | * job list. |
| 286 | * |
| 287 | * They return: |
| 288 | * < 0: error |
| 289 | * 0: success |
| 290 | * > 0: can't process yet. |
| 291 | */ |
| 292 | static int run_complete_job(struct kcopyd_job *job) |
| 293 | { |
| 294 | void *context = job->context; |
| 295 | int read_err = job->read_err; |
| 296 | unsigned int write_err = job->write_err; |
| 297 | kcopyd_notify_fn fn = job->fn; |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 298 | struct kcopyd_client *kc = job->kc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 300 | kcopyd_put_pages(kc, job->pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | mempool_free(job, _job_pool); |
| 302 | fn(read_err, write_err, context); |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 303 | |
| 304 | if (atomic_dec_and_test(&kc->nr_jobs)) |
| 305 | wake_up(&kc->destroyq); |
| 306 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | return 0; |
| 308 | } |
| 309 | |
| 310 | static void complete_io(unsigned long error, void *context) |
| 311 | { |
| 312 | struct kcopyd_job *job = (struct kcopyd_job *) context; |
| 313 | |
| 314 | if (error) { |
| 315 | if (job->rw == WRITE) |
Jonathan Brassow | ce503f5 | 2006-06-26 00:27:30 -0700 | [diff] [blame] | 316 | job->write_err |= error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | else |
| 318 | job->read_err = 1; |
| 319 | |
| 320 | if (!test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) { |
| 321 | push(&_complete_jobs, job); |
| 322 | wake(); |
| 323 | return; |
| 324 | } |
| 325 | } |
| 326 | |
| 327 | if (job->rw == WRITE) |
| 328 | push(&_complete_jobs, job); |
| 329 | |
| 330 | else { |
| 331 | job->rw = WRITE; |
| 332 | push(&_io_jobs, job); |
| 333 | } |
| 334 | |
| 335 | wake(); |
| 336 | } |
| 337 | |
| 338 | /* |
| 339 | * Request io on as many buffer heads as we can currently get for |
| 340 | * a particular job. |
| 341 | */ |
| 342 | static int run_io_job(struct kcopyd_job *job) |
| 343 | { |
| 344 | int r; |
| 345 | |
| 346 | if (job->rw == READ) |
| 347 | r = dm_io_async(1, &job->source, job->rw, |
| 348 | job->pages, |
| 349 | job->offset, complete_io, job); |
| 350 | |
| 351 | else |
| 352 | r = dm_io_async(job->num_dests, job->dests, job->rw, |
| 353 | job->pages, |
| 354 | job->offset, complete_io, job); |
| 355 | |
| 356 | return r; |
| 357 | } |
| 358 | |
| 359 | static int run_pages_job(struct kcopyd_job *job) |
| 360 | { |
| 361 | int r; |
| 362 | |
| 363 | job->nr_pages = dm_div_up(job->dests[0].count + job->offset, |
| 364 | PAGE_SIZE >> 9); |
| 365 | r = kcopyd_get_pages(job->kc, job->nr_pages, &job->pages); |
| 366 | if (!r) { |
| 367 | /* this job is ready for io */ |
| 368 | push(&_io_jobs, job); |
| 369 | return 0; |
| 370 | } |
| 371 | |
| 372 | if (r == -ENOMEM) |
| 373 | /* can't complete now */ |
| 374 | return 1; |
| 375 | |
| 376 | return r; |
| 377 | } |
| 378 | |
| 379 | /* |
| 380 | * Run through a list for as long as possible. Returns the count |
| 381 | * of successful jobs. |
| 382 | */ |
| 383 | static int process_jobs(struct list_head *jobs, int (*fn) (struct kcopyd_job *)) |
| 384 | { |
| 385 | struct kcopyd_job *job; |
| 386 | int r, count = 0; |
| 387 | |
| 388 | while ((job = pop(jobs))) { |
| 389 | |
| 390 | r = fn(job); |
| 391 | |
| 392 | if (r < 0) { |
| 393 | /* error this rogue job */ |
| 394 | if (job->rw == WRITE) |
| 395 | job->write_err = (unsigned int) -1; |
| 396 | else |
| 397 | job->read_err = 1; |
| 398 | push(&_complete_jobs, job); |
| 399 | break; |
| 400 | } |
| 401 | |
| 402 | if (r > 0) { |
| 403 | /* |
| 404 | * We couldn't service this job ATM, so |
| 405 | * push this job back onto the list. |
| 406 | */ |
| 407 | push(jobs, job); |
| 408 | break; |
| 409 | } |
| 410 | |
| 411 | count++; |
| 412 | } |
| 413 | |
| 414 | return count; |
| 415 | } |
| 416 | |
| 417 | /* |
| 418 | * kcopyd does this every time it's woken up. |
| 419 | */ |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 420 | static void do_work(struct work_struct *ignored) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 421 | { |
| 422 | /* |
| 423 | * The order that these are called is *very* important. |
| 424 | * complete jobs can free some pages for pages jobs. |
| 425 | * Pages jobs when successful will jump onto the io jobs |
| 426 | * list. io jobs call wake when they complete and it all |
| 427 | * starts again. |
| 428 | */ |
| 429 | process_jobs(&_complete_jobs, run_complete_job); |
| 430 | process_jobs(&_pages_jobs, run_pages_job); |
| 431 | process_jobs(&_io_jobs, run_io_job); |
| 432 | } |
| 433 | |
| 434 | /* |
| 435 | * If we are copying a small region we just dispatch a single job |
| 436 | * to do the copy, otherwise the io has to be split up into many |
| 437 | * jobs. |
| 438 | */ |
| 439 | static void dispatch_job(struct kcopyd_job *job) |
| 440 | { |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 441 | atomic_inc(&job->kc->nr_jobs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | push(&_pages_jobs, job); |
| 443 | wake(); |
| 444 | } |
| 445 | |
| 446 | #define SUB_JOB_SIZE 128 |
| 447 | static void segment_complete(int read_err, |
| 448 | unsigned int write_err, void *context) |
| 449 | { |
| 450 | /* FIXME: tidy this function */ |
| 451 | sector_t progress = 0; |
| 452 | sector_t count = 0; |
| 453 | struct kcopyd_job *job = (struct kcopyd_job *) context; |
| 454 | |
| 455 | down(&job->lock); |
| 456 | |
| 457 | /* update the error */ |
| 458 | if (read_err) |
| 459 | job->read_err = 1; |
| 460 | |
| 461 | if (write_err) |
Jonathan Brassow | ce503f5 | 2006-06-26 00:27:30 -0700 | [diff] [blame] | 462 | job->write_err |= write_err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | |
| 464 | /* |
| 465 | * Only dispatch more work if there hasn't been an error. |
| 466 | */ |
| 467 | if ((!job->read_err && !job->write_err) || |
| 468 | test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) { |
| 469 | /* get the next chunk of work */ |
| 470 | progress = job->progress; |
| 471 | count = job->source.count - progress; |
| 472 | if (count) { |
| 473 | if (count > SUB_JOB_SIZE) |
| 474 | count = SUB_JOB_SIZE; |
| 475 | |
| 476 | job->progress += count; |
| 477 | } |
| 478 | } |
| 479 | up(&job->lock); |
| 480 | |
| 481 | if (count) { |
| 482 | int i; |
| 483 | struct kcopyd_job *sub_job = mempool_alloc(_job_pool, GFP_NOIO); |
| 484 | |
| 485 | *sub_job = *job; |
| 486 | sub_job->source.sector += progress; |
| 487 | sub_job->source.count = count; |
| 488 | |
| 489 | for (i = 0; i < job->num_dests; i++) { |
| 490 | sub_job->dests[i].sector += progress; |
| 491 | sub_job->dests[i].count = count; |
| 492 | } |
| 493 | |
| 494 | sub_job->fn = segment_complete; |
| 495 | sub_job->context = job; |
| 496 | dispatch_job(sub_job); |
| 497 | |
| 498 | } else if (atomic_dec_and_test(&job->sub_jobs)) { |
| 499 | |
| 500 | /* |
| 501 | * To avoid a race we must keep the job around |
| 502 | * until after the notify function has completed. |
| 503 | * Otherwise the client may try and stop the job |
| 504 | * after we've completed. |
| 505 | */ |
| 506 | job->fn(read_err, write_err, job->context); |
| 507 | mempool_free(job, _job_pool); |
| 508 | } |
| 509 | } |
| 510 | |
| 511 | /* |
| 512 | * Create some little jobs that will do the move between |
| 513 | * them. |
| 514 | */ |
| 515 | #define SPLIT_COUNT 8 |
| 516 | static void split_job(struct kcopyd_job *job) |
| 517 | { |
| 518 | int i; |
| 519 | |
| 520 | atomic_set(&job->sub_jobs, SPLIT_COUNT); |
| 521 | for (i = 0; i < SPLIT_COUNT; i++) |
| 522 | segment_complete(0, 0u, job); |
| 523 | } |
| 524 | |
| 525 | int kcopyd_copy(struct kcopyd_client *kc, struct io_region *from, |
| 526 | unsigned int num_dests, struct io_region *dests, |
| 527 | unsigned int flags, kcopyd_notify_fn fn, void *context) |
| 528 | { |
| 529 | struct kcopyd_job *job; |
| 530 | |
| 531 | /* |
| 532 | * Allocate a new job. |
| 533 | */ |
| 534 | job = mempool_alloc(_job_pool, GFP_NOIO); |
| 535 | |
| 536 | /* |
| 537 | * set up for the read. |
| 538 | */ |
| 539 | job->kc = kc; |
| 540 | job->flags = flags; |
| 541 | job->read_err = 0; |
| 542 | job->write_err = 0; |
| 543 | job->rw = READ; |
| 544 | |
| 545 | job->source = *from; |
| 546 | |
| 547 | job->num_dests = num_dests; |
| 548 | memcpy(&job->dests, dests, sizeof(*dests) * num_dests); |
| 549 | |
| 550 | job->offset = 0; |
| 551 | job->nr_pages = 0; |
| 552 | job->pages = NULL; |
| 553 | |
| 554 | job->fn = fn; |
| 555 | job->context = context; |
| 556 | |
| 557 | if (job->source.count < SUB_JOB_SIZE) |
| 558 | dispatch_job(job); |
| 559 | |
| 560 | else { |
| 561 | init_MUTEX(&job->lock); |
| 562 | job->progress = 0; |
| 563 | split_job(job); |
| 564 | } |
| 565 | |
| 566 | return 0; |
| 567 | } |
| 568 | |
| 569 | /* |
| 570 | * Cancels a kcopyd job, eg. someone might be deactivating a |
| 571 | * mirror. |
| 572 | */ |
Adrian Bunk | 0b56306 | 2006-01-06 00:20:08 -0800 | [diff] [blame] | 573 | #if 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | int kcopyd_cancel(struct kcopyd_job *job, int block) |
| 575 | { |
| 576 | /* FIXME: finish */ |
| 577 | return -1; |
| 578 | } |
Adrian Bunk | 0b56306 | 2006-01-06 00:20:08 -0800 | [diff] [blame] | 579 | #endif /* 0 */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | |
| 581 | /*----------------------------------------------------------------- |
| 582 | * Unit setup |
| 583 | *---------------------------------------------------------------*/ |
Arjan van de Ven | 48c9c27 | 2006-03-27 01:18:20 -0800 | [diff] [blame] | 584 | static DEFINE_MUTEX(_client_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | static LIST_HEAD(_clients); |
| 586 | |
| 587 | static void client_add(struct kcopyd_client *kc) |
| 588 | { |
Arjan van de Ven | 48c9c27 | 2006-03-27 01:18:20 -0800 | [diff] [blame] | 589 | mutex_lock(&_client_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | list_add(&kc->list, &_clients); |
Arjan van de Ven | 48c9c27 | 2006-03-27 01:18:20 -0800 | [diff] [blame] | 591 | mutex_unlock(&_client_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | } |
| 593 | |
| 594 | static void client_del(struct kcopyd_client *kc) |
| 595 | { |
Arjan van de Ven | 48c9c27 | 2006-03-27 01:18:20 -0800 | [diff] [blame] | 596 | mutex_lock(&_client_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 597 | list_del(&kc->list); |
Arjan van de Ven | 48c9c27 | 2006-03-27 01:18:20 -0800 | [diff] [blame] | 598 | mutex_unlock(&_client_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 599 | } |
| 600 | |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 601 | static DEFINE_MUTEX(kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | static int kcopyd_clients = 0; |
| 603 | |
| 604 | static int kcopyd_init(void) |
| 605 | { |
| 606 | int r; |
| 607 | |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 608 | mutex_lock(&kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | |
| 610 | if (kcopyd_clients) { |
| 611 | /* Already initialized. */ |
| 612 | kcopyd_clients++; |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 613 | mutex_unlock(&kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 614 | return 0; |
| 615 | } |
| 616 | |
| 617 | r = jobs_init(); |
| 618 | if (r) { |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 619 | mutex_unlock(&kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 620 | return r; |
| 621 | } |
| 622 | |
| 623 | _kcopyd_wq = create_singlethread_workqueue("kcopyd"); |
| 624 | if (!_kcopyd_wq) { |
| 625 | jobs_exit(); |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 626 | mutex_unlock(&kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 627 | return -ENOMEM; |
| 628 | } |
| 629 | |
| 630 | kcopyd_clients++; |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 631 | INIT_WORK(&_kcopyd_work, do_work); |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 632 | mutex_unlock(&kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 633 | return 0; |
| 634 | } |
| 635 | |
| 636 | static void kcopyd_exit(void) |
| 637 | { |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 638 | mutex_lock(&kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | kcopyd_clients--; |
| 640 | if (!kcopyd_clients) { |
| 641 | jobs_exit(); |
| 642 | destroy_workqueue(_kcopyd_wq); |
| 643 | _kcopyd_wq = NULL; |
| 644 | } |
Ingo Molnar | 14cc3e2 | 2006-03-26 01:37:14 -0800 | [diff] [blame] | 645 | mutex_unlock(&kcopyd_init_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | } |
| 647 | |
| 648 | int kcopyd_client_create(unsigned int nr_pages, struct kcopyd_client **result) |
| 649 | { |
| 650 | int r = 0; |
| 651 | struct kcopyd_client *kc; |
| 652 | |
| 653 | r = kcopyd_init(); |
| 654 | if (r) |
| 655 | return r; |
| 656 | |
| 657 | kc = kmalloc(sizeof(*kc), GFP_KERNEL); |
| 658 | if (!kc) { |
| 659 | kcopyd_exit(); |
| 660 | return -ENOMEM; |
| 661 | } |
| 662 | |
| 663 | spin_lock_init(&kc->lock); |
| 664 | kc->pages = NULL; |
| 665 | kc->nr_pages = kc->nr_free_pages = 0; |
| 666 | r = client_alloc_pages(kc, nr_pages); |
| 667 | if (r) { |
| 668 | kfree(kc); |
| 669 | kcopyd_exit(); |
| 670 | return r; |
| 671 | } |
| 672 | |
| 673 | r = dm_io_get(nr_pages); |
| 674 | if (r) { |
| 675 | client_free_pages(kc); |
| 676 | kfree(kc); |
| 677 | kcopyd_exit(); |
| 678 | return r; |
| 679 | } |
| 680 | |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 681 | init_waitqueue_head(&kc->destroyq); |
| 682 | atomic_set(&kc->nr_jobs, 0); |
| 683 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 684 | client_add(kc); |
| 685 | *result = kc; |
| 686 | return 0; |
| 687 | } |
| 688 | |
| 689 | void kcopyd_client_destroy(struct kcopyd_client *kc) |
| 690 | { |
Alasdair G Kergon | 138728dc | 2006-03-27 01:17:50 -0800 | [diff] [blame] | 691 | /* Wait for completion of all jobs submitted by this client. */ |
| 692 | wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs)); |
| 693 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 694 | dm_io_put(kc->nr_pages); |
| 695 | client_free_pages(kc); |
| 696 | client_del(kc); |
| 697 | kfree(kc); |
| 698 | kcopyd_exit(); |
| 699 | } |
| 700 | |
| 701 | EXPORT_SYMBOL(kcopyd_client_create); |
| 702 | EXPORT_SYMBOL(kcopyd_client_destroy); |
| 703 | EXPORT_SYMBOL(kcopyd_copy); |