1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/errno.h> 3 #include <linux/numa.h> 4 #include <linux/slab.h> 5 #include <linux/rculist.h> 6 #include <linux/threads.h> 7 #include <linux/preempt.h> 8 #include <linux/irqflags.h> 9 #include <linux/vmalloc.h> 10 #include <linux/mm.h> 11 #include <linux/module.h> 12 #include <linux/device-mapper.h> 13 14 #include "dm-core.h" 15 #include "dm-stats.h" 16 17 #define DM_MSG_PREFIX "stats" 18 19 static int dm_stat_need_rcu_barrier; 20 21 /* 22 * Using 64-bit values to avoid overflow (which is a 23 * problem that block/genhd.c's IO accounting has). 24 */ 25 struct dm_stat_percpu { 26 unsigned long long sectors[2]; 27 unsigned long long ios[2]; 28 unsigned long long merges[2]; 29 unsigned long long ticks[2]; 30 unsigned long long io_ticks[2]; 31 unsigned long long io_ticks_total; 32 unsigned long long time_in_queue; 33 unsigned long long *histogram; 34 }; 35 36 struct dm_stat_shared { 37 atomic_t in_flight[2]; 38 unsigned long long stamp; 39 struct dm_stat_percpu tmp; 40 }; 41 42 struct dm_stat { 43 struct list_head list_entry; 44 int id; 45 unsigned stat_flags; 46 size_t n_entries; 47 sector_t start; 48 sector_t end; 49 sector_t step; 50 unsigned n_histogram_entries; 51 unsigned long long *histogram_boundaries; 52 const char *program_id; 53 const char *aux_data; 54 struct rcu_head rcu_head; 55 size_t shared_alloc_size; 56 size_t percpu_alloc_size; 57 size_t histogram_alloc_size; 58 struct dm_stat_percpu *stat_percpu[NR_CPUS]; 59 struct dm_stat_shared stat_shared[]; 60 }; 61 62 #define STAT_PRECISE_TIMESTAMPS 1 63 64 struct dm_stats_last_position { 65 sector_t last_sector; 66 unsigned last_rw; 67 }; 68 69 /* 70 * A typo on the command line could possibly make the kernel run out of memory 71 * and crash. To prevent the crash we account all used memory. We fail if we 72 * exhaust 1/4 of all memory or 1/2 of vmalloc space. 73 */ 74 #define DM_STATS_MEMORY_FACTOR 4 75 #define DM_STATS_VMALLOC_FACTOR 2 76 77 static DEFINE_SPINLOCK(shared_memory_lock); 78 79 static unsigned long shared_memory_amount; 80 81 static bool __check_shared_memory(size_t alloc_size) 82 { 83 size_t a; 84 85 a = shared_memory_amount + alloc_size; 86 if (a < shared_memory_amount) 87 return false; 88 if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR) 89 return false; 90 #ifdef CONFIG_MMU 91 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR) 92 return false; 93 #endif 94 return true; 95 } 96 97 static bool check_shared_memory(size_t alloc_size) 98 { 99 bool ret; 100 101 spin_lock_irq(&shared_memory_lock); 102 103 ret = __check_shared_memory(alloc_size); 104 105 spin_unlock_irq(&shared_memory_lock); 106 107 return ret; 108 } 109 110 static bool claim_shared_memory(size_t alloc_size) 111 { 112 spin_lock_irq(&shared_memory_lock); 113 114 if (!__check_shared_memory(alloc_size)) { 115 spin_unlock_irq(&shared_memory_lock); 116 return false; 117 } 118 119 shared_memory_amount += alloc_size; 120 121 spin_unlock_irq(&shared_memory_lock); 122 123 return true; 124 } 125 126 static void free_shared_memory(size_t alloc_size) 127 { 128 unsigned long flags; 129 130 spin_lock_irqsave(&shared_memory_lock, flags); 131 132 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) { 133 spin_unlock_irqrestore(&shared_memory_lock, flags); 134 DMCRIT("Memory usage accounting bug."); 135 return; 136 } 137 138 shared_memory_amount -= alloc_size; 139 140 spin_unlock_irqrestore(&shared_memory_lock, flags); 141 } 142 143 static void *dm_kvzalloc(size_t alloc_size, int node) 144 { 145 void *p; 146 147 if (!claim_shared_memory(alloc_size)) 148 return NULL; 149 150 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node); 151 if (p) 152 return p; 153 154 free_shared_memory(alloc_size); 155 156 return NULL; 157 } 158 159 static void dm_kvfree(void *ptr, size_t alloc_size) 160 { 161 if (!ptr) 162 return; 163 164 free_shared_memory(alloc_size); 165 166 kvfree(ptr); 167 } 168 169 static void dm_stat_free(struct rcu_head *head) 170 { 171 int cpu; 172 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head); 173 174 kfree(s->histogram_boundaries); 175 kfree(s->program_id); 176 kfree(s->aux_data); 177 for_each_possible_cpu(cpu) { 178 dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size); 179 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size); 180 } 181 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size); 182 dm_kvfree(s, s->shared_alloc_size); 183 } 184 185 static int dm_stat_in_flight(struct dm_stat_shared *shared) 186 { 187 return atomic_read(&shared->in_flight[READ]) + 188 atomic_read(&shared->in_flight[WRITE]); 189 } 190 191 void dm_stats_init(struct dm_stats *stats) 192 { 193 int cpu; 194 struct dm_stats_last_position *last; 195 196 mutex_init(&stats->mutex); 197 INIT_LIST_HEAD(&stats->list); 198 stats->precise_timestamps = false; 199 stats->last = alloc_percpu(struct dm_stats_last_position); 200 for_each_possible_cpu(cpu) { 201 last = per_cpu_ptr(stats->last, cpu); 202 last->last_sector = (sector_t)ULLONG_MAX; 203 last->last_rw = UINT_MAX; 204 } 205 } 206 207 void dm_stats_cleanup(struct dm_stats *stats) 208 { 209 size_t ni; 210 struct dm_stat *s; 211 struct dm_stat_shared *shared; 212 213 while (!list_empty(&stats->list)) { 214 s = container_of(stats->list.next, struct dm_stat, list_entry); 215 list_del(&s->list_entry); 216 for (ni = 0; ni < s->n_entries; ni++) { 217 shared = &s->stat_shared[ni]; 218 if (WARN_ON(dm_stat_in_flight(shared))) { 219 DMCRIT("leaked in-flight counter at index %lu " 220 "(start %llu, end %llu, step %llu): reads %d, writes %d", 221 (unsigned long)ni, 222 (unsigned long long)s->start, 223 (unsigned long long)s->end, 224 (unsigned long long)s->step, 225 atomic_read(&shared->in_flight[READ]), 226 atomic_read(&shared->in_flight[WRITE])); 227 } 228 cond_resched(); 229 } 230 dm_stat_free(&s->rcu_head); 231 } 232 free_percpu(stats->last); 233 mutex_destroy(&stats->mutex); 234 } 235 236 static void dm_stats_recalc_precise_timestamps(struct dm_stats *stats) 237 { 238 struct list_head *l; 239 struct dm_stat *tmp_s; 240 bool precise_timestamps = false; 241 242 list_for_each(l, &stats->list) { 243 tmp_s = container_of(l, struct dm_stat, list_entry); 244 if (tmp_s->stat_flags & STAT_PRECISE_TIMESTAMPS) { 245 precise_timestamps = true; 246 break; 247 } 248 } 249 stats->precise_timestamps = precise_timestamps; 250 } 251 252 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, 253 sector_t step, unsigned stat_flags, 254 unsigned n_histogram_entries, 255 unsigned long long *histogram_boundaries, 256 const char *program_id, const char *aux_data, 257 void (*suspend_callback)(struct mapped_device *), 258 void (*resume_callback)(struct mapped_device *), 259 struct mapped_device *md) 260 { 261 struct list_head *l; 262 struct dm_stat *s, *tmp_s; 263 sector_t n_entries; 264 size_t ni; 265 size_t shared_alloc_size; 266 size_t percpu_alloc_size; 267 size_t histogram_alloc_size; 268 struct dm_stat_percpu *p; 269 int cpu; 270 int ret_id; 271 int r; 272 273 if (end < start || !step) 274 return -EINVAL; 275 276 n_entries = end - start; 277 if (dm_sector_div64(n_entries, step)) 278 n_entries++; 279 280 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1)) 281 return -EOVERFLOW; 282 283 shared_alloc_size = struct_size(s, stat_shared, n_entries); 284 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries) 285 return -EOVERFLOW; 286 287 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu); 288 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries) 289 return -EOVERFLOW; 290 291 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long); 292 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long)) 293 return -EOVERFLOW; 294 295 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size + 296 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size))) 297 return -ENOMEM; 298 299 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE); 300 if (!s) 301 return -ENOMEM; 302 303 s->stat_flags = stat_flags; 304 s->n_entries = n_entries; 305 s->start = start; 306 s->end = end; 307 s->step = step; 308 s->shared_alloc_size = shared_alloc_size; 309 s->percpu_alloc_size = percpu_alloc_size; 310 s->histogram_alloc_size = histogram_alloc_size; 311 312 s->n_histogram_entries = n_histogram_entries; 313 s->histogram_boundaries = kmemdup(histogram_boundaries, 314 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL); 315 if (!s->histogram_boundaries) { 316 r = -ENOMEM; 317 goto out; 318 } 319 320 s->program_id = kstrdup(program_id, GFP_KERNEL); 321 if (!s->program_id) { 322 r = -ENOMEM; 323 goto out; 324 } 325 s->aux_data = kstrdup(aux_data, GFP_KERNEL); 326 if (!s->aux_data) { 327 r = -ENOMEM; 328 goto out; 329 } 330 331 for (ni = 0; ni < n_entries; ni++) { 332 atomic_set(&s->stat_shared[ni].in_flight[READ], 0); 333 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0); 334 cond_resched(); 335 } 336 337 if (s->n_histogram_entries) { 338 unsigned long long *hi; 339 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE); 340 if (!hi) { 341 r = -ENOMEM; 342 goto out; 343 } 344 for (ni = 0; ni < n_entries; ni++) { 345 s->stat_shared[ni].tmp.histogram = hi; 346 hi += s->n_histogram_entries + 1; 347 cond_resched(); 348 } 349 } 350 351 for_each_possible_cpu(cpu) { 352 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu)); 353 if (!p) { 354 r = -ENOMEM; 355 goto out; 356 } 357 s->stat_percpu[cpu] = p; 358 if (s->n_histogram_entries) { 359 unsigned long long *hi; 360 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu)); 361 if (!hi) { 362 r = -ENOMEM; 363 goto out; 364 } 365 for (ni = 0; ni < n_entries; ni++) { 366 p[ni].histogram = hi; 367 hi += s->n_histogram_entries + 1; 368 cond_resched(); 369 } 370 } 371 } 372 373 /* 374 * Suspend/resume to make sure there is no i/o in flight, 375 * so that newly created statistics will be exact. 376 * 377 * (note: we couldn't suspend earlier because we must not 378 * allocate memory while suspended) 379 */ 380 suspend_callback(md); 381 382 mutex_lock(&stats->mutex); 383 s->id = 0; 384 list_for_each(l, &stats->list) { 385 tmp_s = container_of(l, struct dm_stat, list_entry); 386 if (WARN_ON(tmp_s->id < s->id)) { 387 r = -EINVAL; 388 goto out_unlock_resume; 389 } 390 if (tmp_s->id > s->id) 391 break; 392 if (unlikely(s->id == INT_MAX)) { 393 r = -ENFILE; 394 goto out_unlock_resume; 395 } 396 s->id++; 397 } 398 ret_id = s->id; 399 list_add_tail_rcu(&s->list_entry, l); 400 401 dm_stats_recalc_precise_timestamps(stats); 402 403 if (!static_key_enabled(&stats_enabled.key)) 404 static_branch_enable(&stats_enabled); 405 406 mutex_unlock(&stats->mutex); 407 408 resume_callback(md); 409 410 return ret_id; 411 412 out_unlock_resume: 413 mutex_unlock(&stats->mutex); 414 resume_callback(md); 415 out: 416 dm_stat_free(&s->rcu_head); 417 return r; 418 } 419 420 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id) 421 { 422 struct dm_stat *s; 423 424 list_for_each_entry(s, &stats->list, list_entry) { 425 if (s->id > id) 426 break; 427 if (s->id == id) 428 return s; 429 } 430 431 return NULL; 432 } 433 434 static int dm_stats_delete(struct dm_stats *stats, int id) 435 { 436 struct dm_stat *s; 437 int cpu; 438 439 mutex_lock(&stats->mutex); 440 441 s = __dm_stats_find(stats, id); 442 if (!s) { 443 mutex_unlock(&stats->mutex); 444 return -ENOENT; 445 } 446 447 list_del_rcu(&s->list_entry); 448 449 dm_stats_recalc_precise_timestamps(stats); 450 451 mutex_unlock(&stats->mutex); 452 453 /* 454 * vfree can't be called from RCU callback 455 */ 456 for_each_possible_cpu(cpu) 457 if (is_vmalloc_addr(s->stat_percpu) || 458 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram)) 459 goto do_sync_free; 460 if (is_vmalloc_addr(s) || 461 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) { 462 do_sync_free: 463 synchronize_rcu_expedited(); 464 dm_stat_free(&s->rcu_head); 465 } else { 466 WRITE_ONCE(dm_stat_need_rcu_barrier, 1); 467 call_rcu(&s->rcu_head, dm_stat_free); 468 } 469 return 0; 470 } 471 472 static int dm_stats_list(struct dm_stats *stats, const char *program, 473 char *result, unsigned maxlen) 474 { 475 struct dm_stat *s; 476 sector_t len; 477 unsigned sz = 0; 478 479 /* 480 * Output format: 481 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data> 482 */ 483 484 mutex_lock(&stats->mutex); 485 list_for_each_entry(s, &stats->list, list_entry) { 486 if (!program || !strcmp(program, s->program_id)) { 487 len = s->end - s->start; 488 DMEMIT("%d: %llu+%llu %llu %s %s", s->id, 489 (unsigned long long)s->start, 490 (unsigned long long)len, 491 (unsigned long long)s->step, 492 s->program_id, 493 s->aux_data); 494 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS) 495 DMEMIT(" precise_timestamps"); 496 if (s->n_histogram_entries) { 497 unsigned i; 498 DMEMIT(" histogram:"); 499 for (i = 0; i < s->n_histogram_entries; i++) { 500 if (i) 501 DMEMIT(","); 502 DMEMIT("%llu", s->histogram_boundaries[i]); 503 } 504 } 505 DMEMIT("\n"); 506 } 507 cond_resched(); 508 } 509 mutex_unlock(&stats->mutex); 510 511 return 1; 512 } 513 514 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared, 515 struct dm_stat_percpu *p) 516 { 517 /* 518 * This is racy, but so is part_round_stats_single. 519 */ 520 unsigned long long now, difference; 521 unsigned in_flight_read, in_flight_write; 522 523 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS))) 524 now = jiffies; 525 else 526 now = ktime_to_ns(ktime_get()); 527 528 difference = now - shared->stamp; 529 if (!difference) 530 return; 531 532 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]); 533 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]); 534 if (in_flight_read) 535 p->io_ticks[READ] += difference; 536 if (in_flight_write) 537 p->io_ticks[WRITE] += difference; 538 if (in_flight_read + in_flight_write) { 539 p->io_ticks_total += difference; 540 p->time_in_queue += (in_flight_read + in_flight_write) * difference; 541 } 542 shared->stamp = now; 543 } 544 545 static void dm_stat_for_entry(struct dm_stat *s, size_t entry, 546 int idx, sector_t len, 547 struct dm_stats_aux *stats_aux, bool end, 548 unsigned long duration_jiffies) 549 { 550 struct dm_stat_shared *shared = &s->stat_shared[entry]; 551 struct dm_stat_percpu *p; 552 553 /* 554 * For strict correctness we should use local_irq_save/restore 555 * instead of preempt_disable/enable. 556 * 557 * preempt_disable/enable is racy if the driver finishes bios 558 * from non-interrupt context as well as from interrupt context 559 * or from more different interrupts. 560 * 561 * On 64-bit architectures the race only results in not counting some 562 * events, so it is acceptable. On 32-bit architectures the race could 563 * cause the counter going off by 2^32, so we need to do proper locking 564 * there. 565 * 566 * part_stat_lock()/part_stat_unlock() have this race too. 567 */ 568 #if BITS_PER_LONG == 32 569 unsigned long flags; 570 local_irq_save(flags); 571 #else 572 preempt_disable(); 573 #endif 574 p = &s->stat_percpu[smp_processor_id()][entry]; 575 576 if (!end) { 577 dm_stat_round(s, shared, p); 578 atomic_inc(&shared->in_flight[idx]); 579 } else { 580 unsigned long long duration; 581 dm_stat_round(s, shared, p); 582 atomic_dec(&shared->in_flight[idx]); 583 p->sectors[idx] += len; 584 p->ios[idx] += 1; 585 p->merges[idx] += stats_aux->merged; 586 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) { 587 p->ticks[idx] += duration_jiffies; 588 duration = jiffies_to_msecs(duration_jiffies); 589 } else { 590 p->ticks[idx] += stats_aux->duration_ns; 591 duration = stats_aux->duration_ns; 592 } 593 if (s->n_histogram_entries) { 594 unsigned lo = 0, hi = s->n_histogram_entries + 1; 595 while (lo + 1 < hi) { 596 unsigned mid = (lo + hi) / 2; 597 if (s->histogram_boundaries[mid - 1] > duration) { 598 hi = mid; 599 } else { 600 lo = mid; 601 } 602 603 } 604 p->histogram[lo]++; 605 } 606 } 607 608 #if BITS_PER_LONG == 32 609 local_irq_restore(flags); 610 #else 611 preempt_enable(); 612 #endif 613 } 614 615 static void __dm_stat_bio(struct dm_stat *s, int bi_rw, 616 sector_t bi_sector, sector_t end_sector, 617 bool end, unsigned long duration_jiffies, 618 struct dm_stats_aux *stats_aux) 619 { 620 sector_t rel_sector, offset, todo, fragment_len; 621 size_t entry; 622 623 if (end_sector <= s->start || bi_sector >= s->end) 624 return; 625 if (unlikely(bi_sector < s->start)) { 626 rel_sector = 0; 627 todo = end_sector - s->start; 628 } else { 629 rel_sector = bi_sector - s->start; 630 todo = end_sector - bi_sector; 631 } 632 if (unlikely(end_sector > s->end)) 633 todo -= (end_sector - s->end); 634 635 offset = dm_sector_div64(rel_sector, s->step); 636 entry = rel_sector; 637 do { 638 if (WARN_ON_ONCE(entry >= s->n_entries)) { 639 DMCRIT("Invalid area access in region id %d", s->id); 640 return; 641 } 642 fragment_len = todo; 643 if (fragment_len > s->step - offset) 644 fragment_len = s->step - offset; 645 dm_stat_for_entry(s, entry, bi_rw, fragment_len, 646 stats_aux, end, duration_jiffies); 647 todo -= fragment_len; 648 entry++; 649 offset = 0; 650 } while (unlikely(todo != 0)); 651 } 652 653 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw, 654 sector_t bi_sector, unsigned bi_sectors, bool end, 655 unsigned long start_time, 656 struct dm_stats_aux *stats_aux) 657 { 658 struct dm_stat *s; 659 sector_t end_sector; 660 struct dm_stats_last_position *last; 661 bool got_precise_time; 662 unsigned long duration_jiffies = 0; 663 664 if (unlikely(!bi_sectors)) 665 return; 666 667 end_sector = bi_sector + bi_sectors; 668 669 if (!end) { 670 /* 671 * A race condition can at worst result in the merged flag being 672 * misrepresented, so we don't have to disable preemption here. 673 */ 674 last = raw_cpu_ptr(stats->last); 675 stats_aux->merged = 676 (bi_sector == (READ_ONCE(last->last_sector) && 677 ((bi_rw == WRITE) == 678 (READ_ONCE(last->last_rw) == WRITE)) 679 )); 680 WRITE_ONCE(last->last_sector, end_sector); 681 WRITE_ONCE(last->last_rw, bi_rw); 682 } else 683 duration_jiffies = jiffies - start_time; 684 685 rcu_read_lock(); 686 687 got_precise_time = false; 688 list_for_each_entry_rcu(s, &stats->list, list_entry) { 689 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) { 690 /* start (!end) duration_ns is set by DM core's alloc_io() */ 691 if (end) 692 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns; 693 got_precise_time = true; 694 } 695 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux); 696 } 697 698 rcu_read_unlock(); 699 } 700 701 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared, 702 struct dm_stat *s, size_t x) 703 { 704 int cpu; 705 struct dm_stat_percpu *p; 706 707 local_irq_disable(); 708 p = &s->stat_percpu[smp_processor_id()][x]; 709 dm_stat_round(s, shared, p); 710 local_irq_enable(); 711 712 shared->tmp.sectors[READ] = 0; 713 shared->tmp.sectors[WRITE] = 0; 714 shared->tmp.ios[READ] = 0; 715 shared->tmp.ios[WRITE] = 0; 716 shared->tmp.merges[READ] = 0; 717 shared->tmp.merges[WRITE] = 0; 718 shared->tmp.ticks[READ] = 0; 719 shared->tmp.ticks[WRITE] = 0; 720 shared->tmp.io_ticks[READ] = 0; 721 shared->tmp.io_ticks[WRITE] = 0; 722 shared->tmp.io_ticks_total = 0; 723 shared->tmp.time_in_queue = 0; 724 725 if (s->n_histogram_entries) 726 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long)); 727 728 for_each_possible_cpu(cpu) { 729 p = &s->stat_percpu[cpu][x]; 730 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]); 731 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]); 732 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]); 733 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]); 734 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]); 735 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]); 736 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]); 737 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]); 738 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]); 739 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]); 740 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total); 741 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue); 742 if (s->n_histogram_entries) { 743 unsigned i; 744 for (i = 0; i < s->n_histogram_entries + 1; i++) 745 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]); 746 } 747 } 748 } 749 750 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end, 751 bool init_tmp_percpu_totals) 752 { 753 size_t x; 754 struct dm_stat_shared *shared; 755 struct dm_stat_percpu *p; 756 757 for (x = idx_start; x < idx_end; x++) { 758 shared = &s->stat_shared[x]; 759 if (init_tmp_percpu_totals) 760 __dm_stat_init_temporary_percpu_totals(shared, s, x); 761 local_irq_disable(); 762 p = &s->stat_percpu[smp_processor_id()][x]; 763 p->sectors[READ] -= shared->tmp.sectors[READ]; 764 p->sectors[WRITE] -= shared->tmp.sectors[WRITE]; 765 p->ios[READ] -= shared->tmp.ios[READ]; 766 p->ios[WRITE] -= shared->tmp.ios[WRITE]; 767 p->merges[READ] -= shared->tmp.merges[READ]; 768 p->merges[WRITE] -= shared->tmp.merges[WRITE]; 769 p->ticks[READ] -= shared->tmp.ticks[READ]; 770 p->ticks[WRITE] -= shared->tmp.ticks[WRITE]; 771 p->io_ticks[READ] -= shared->tmp.io_ticks[READ]; 772 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE]; 773 p->io_ticks_total -= shared->tmp.io_ticks_total; 774 p->time_in_queue -= shared->tmp.time_in_queue; 775 local_irq_enable(); 776 if (s->n_histogram_entries) { 777 unsigned i; 778 for (i = 0; i < s->n_histogram_entries + 1; i++) { 779 local_irq_disable(); 780 p = &s->stat_percpu[smp_processor_id()][x]; 781 p->histogram[i] -= shared->tmp.histogram[i]; 782 local_irq_enable(); 783 } 784 } 785 cond_resched(); 786 } 787 } 788 789 static int dm_stats_clear(struct dm_stats *stats, int id) 790 { 791 struct dm_stat *s; 792 793 mutex_lock(&stats->mutex); 794 795 s = __dm_stats_find(stats, id); 796 if (!s) { 797 mutex_unlock(&stats->mutex); 798 return -ENOENT; 799 } 800 801 __dm_stat_clear(s, 0, s->n_entries, true); 802 803 mutex_unlock(&stats->mutex); 804 805 return 1; 806 } 807 808 /* 809 * This is like jiffies_to_msec, but works for 64-bit values. 810 */ 811 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j) 812 { 813 unsigned long long result; 814 unsigned mult; 815 816 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS) 817 return j; 818 819 result = 0; 820 if (j) 821 result = jiffies_to_msecs(j & 0x3fffff); 822 if (j >= 1 << 22) { 823 mult = jiffies_to_msecs(1 << 22); 824 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff); 825 } 826 if (j >= 1ULL << 44) 827 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44); 828 829 return result; 830 } 831 832 static int dm_stats_print(struct dm_stats *stats, int id, 833 size_t idx_start, size_t idx_len, 834 bool clear, char *result, unsigned maxlen) 835 { 836 unsigned sz = 0; 837 struct dm_stat *s; 838 size_t x; 839 sector_t start, end, step; 840 size_t idx_end; 841 struct dm_stat_shared *shared; 842 843 /* 844 * Output format: 845 * <start_sector>+<length> counters 846 */ 847 848 mutex_lock(&stats->mutex); 849 850 s = __dm_stats_find(stats, id); 851 if (!s) { 852 mutex_unlock(&stats->mutex); 853 return -ENOENT; 854 } 855 856 idx_end = idx_start + idx_len; 857 if (idx_end < idx_start || 858 idx_end > s->n_entries) 859 idx_end = s->n_entries; 860 861 if (idx_start > idx_end) 862 idx_start = idx_end; 863 864 step = s->step; 865 start = s->start + (step * idx_start); 866 867 for (x = idx_start; x < idx_end; x++, start = end) { 868 shared = &s->stat_shared[x]; 869 end = start + step; 870 if (unlikely(end > s->end)) 871 end = s->end; 872 873 __dm_stat_init_temporary_percpu_totals(shared, s, x); 874 875 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu", 876 (unsigned long long)start, 877 (unsigned long long)step, 878 shared->tmp.ios[READ], 879 shared->tmp.merges[READ], 880 shared->tmp.sectors[READ], 881 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]), 882 shared->tmp.ios[WRITE], 883 shared->tmp.merges[WRITE], 884 shared->tmp.sectors[WRITE], 885 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]), 886 dm_stat_in_flight(shared), 887 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total), 888 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue), 889 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]), 890 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE])); 891 if (s->n_histogram_entries) { 892 unsigned i; 893 for (i = 0; i < s->n_histogram_entries + 1; i++) { 894 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]); 895 } 896 } 897 DMEMIT("\n"); 898 899 if (unlikely(sz + 1 >= maxlen)) 900 goto buffer_overflow; 901 902 cond_resched(); 903 } 904 905 if (clear) 906 __dm_stat_clear(s, idx_start, idx_end, false); 907 908 buffer_overflow: 909 mutex_unlock(&stats->mutex); 910 911 return 1; 912 } 913 914 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data) 915 { 916 struct dm_stat *s; 917 const char *new_aux_data; 918 919 mutex_lock(&stats->mutex); 920 921 s = __dm_stats_find(stats, id); 922 if (!s) { 923 mutex_unlock(&stats->mutex); 924 return -ENOENT; 925 } 926 927 new_aux_data = kstrdup(aux_data, GFP_KERNEL); 928 if (!new_aux_data) { 929 mutex_unlock(&stats->mutex); 930 return -ENOMEM; 931 } 932 933 kfree(s->aux_data); 934 s->aux_data = new_aux_data; 935 936 mutex_unlock(&stats->mutex); 937 938 return 0; 939 } 940 941 static int parse_histogram(const char *h, unsigned *n_histogram_entries, 942 unsigned long long **histogram_boundaries) 943 { 944 const char *q; 945 unsigned n; 946 unsigned long long last; 947 948 *n_histogram_entries = 1; 949 for (q = h; *q; q++) 950 if (*q == ',') 951 (*n_histogram_entries)++; 952 953 *histogram_boundaries = kmalloc_array(*n_histogram_entries, 954 sizeof(unsigned long long), 955 GFP_KERNEL); 956 if (!*histogram_boundaries) 957 return -ENOMEM; 958 959 n = 0; 960 last = 0; 961 while (1) { 962 unsigned long long hi; 963 int s; 964 char ch; 965 s = sscanf(h, "%llu%c", &hi, &ch); 966 if (!s || (s == 2 && ch != ',')) 967 return -EINVAL; 968 if (hi <= last) 969 return -EINVAL; 970 last = hi; 971 (*histogram_boundaries)[n] = hi; 972 if (s == 1) 973 return 0; 974 h = strchr(h, ',') + 1; 975 n++; 976 } 977 } 978 979 static int message_stats_create(struct mapped_device *md, 980 unsigned argc, char **argv, 981 char *result, unsigned maxlen) 982 { 983 int r; 984 int id; 985 char dummy; 986 unsigned long long start, end, len, step; 987 unsigned divisor; 988 const char *program_id, *aux_data; 989 unsigned stat_flags = 0; 990 991 unsigned n_histogram_entries = 0; 992 unsigned long long *histogram_boundaries = NULL; 993 994 struct dm_arg_set as, as_backup; 995 const char *a; 996 unsigned feature_args; 997 998 /* 999 * Input format: 1000 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]] 1001 */ 1002 1003 if (argc < 3) 1004 goto ret_einval; 1005 1006 as.argc = argc; 1007 as.argv = argv; 1008 dm_consume_args(&as, 1); 1009 1010 a = dm_shift_arg(&as); 1011 if (!strcmp(a, "-")) { 1012 start = 0; 1013 len = dm_get_size(md); 1014 if (!len) 1015 len = 1; 1016 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 || 1017 start != (sector_t)start || len != (sector_t)len) 1018 goto ret_einval; 1019 1020 end = start + len; 1021 if (start >= end) 1022 goto ret_einval; 1023 1024 a = dm_shift_arg(&as); 1025 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) { 1026 if (!divisor) 1027 return -EINVAL; 1028 step = end - start; 1029 if (do_div(step, divisor)) 1030 step++; 1031 if (!step) 1032 step = 1; 1033 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 || 1034 step != (sector_t)step || !step) 1035 goto ret_einval; 1036 1037 as_backup = as; 1038 a = dm_shift_arg(&as); 1039 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) { 1040 while (feature_args--) { 1041 a = dm_shift_arg(&as); 1042 if (!a) 1043 goto ret_einval; 1044 if (!strcasecmp(a, "precise_timestamps")) 1045 stat_flags |= STAT_PRECISE_TIMESTAMPS; 1046 else if (!strncasecmp(a, "histogram:", 10)) { 1047 if (n_histogram_entries) 1048 goto ret_einval; 1049 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries))) 1050 goto ret; 1051 } else 1052 goto ret_einval; 1053 } 1054 } else { 1055 as = as_backup; 1056 } 1057 1058 program_id = "-"; 1059 aux_data = "-"; 1060 1061 a = dm_shift_arg(&as); 1062 if (a) 1063 program_id = a; 1064 1065 a = dm_shift_arg(&as); 1066 if (a) 1067 aux_data = a; 1068 1069 if (as.argc) 1070 goto ret_einval; 1071 1072 /* 1073 * If a buffer overflow happens after we created the region, 1074 * it's too late (the userspace would retry with a larger 1075 * buffer, but the region id that caused the overflow is already 1076 * leaked). So we must detect buffer overflow in advance. 1077 */ 1078 snprintf(result, maxlen, "%d", INT_MAX); 1079 if (dm_message_test_buffer_overflow(result, maxlen)) { 1080 r = 1; 1081 goto ret; 1082 } 1083 1084 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags, 1085 n_histogram_entries, histogram_boundaries, program_id, aux_data, 1086 dm_internal_suspend_fast, dm_internal_resume_fast, md); 1087 if (id < 0) { 1088 r = id; 1089 goto ret; 1090 } 1091 1092 snprintf(result, maxlen, "%d", id); 1093 1094 r = 1; 1095 goto ret; 1096 1097 ret_einval: 1098 r = -EINVAL; 1099 ret: 1100 kfree(histogram_boundaries); 1101 return r; 1102 } 1103 1104 static int message_stats_delete(struct mapped_device *md, 1105 unsigned argc, char **argv) 1106 { 1107 int id; 1108 char dummy; 1109 1110 if (argc != 2) 1111 return -EINVAL; 1112 1113 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1114 return -EINVAL; 1115 1116 return dm_stats_delete(dm_get_stats(md), id); 1117 } 1118 1119 static int message_stats_clear(struct mapped_device *md, 1120 unsigned argc, char **argv) 1121 { 1122 int id; 1123 char dummy; 1124 1125 if (argc != 2) 1126 return -EINVAL; 1127 1128 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1129 return -EINVAL; 1130 1131 return dm_stats_clear(dm_get_stats(md), id); 1132 } 1133 1134 static int message_stats_list(struct mapped_device *md, 1135 unsigned argc, char **argv, 1136 char *result, unsigned maxlen) 1137 { 1138 int r; 1139 const char *program = NULL; 1140 1141 if (argc < 1 || argc > 2) 1142 return -EINVAL; 1143 1144 if (argc > 1) { 1145 program = kstrdup(argv[1], GFP_KERNEL); 1146 if (!program) 1147 return -ENOMEM; 1148 } 1149 1150 r = dm_stats_list(dm_get_stats(md), program, result, maxlen); 1151 1152 kfree(program); 1153 1154 return r; 1155 } 1156 1157 static int message_stats_print(struct mapped_device *md, 1158 unsigned argc, char **argv, bool clear, 1159 char *result, unsigned maxlen) 1160 { 1161 int id; 1162 char dummy; 1163 unsigned long idx_start = 0, idx_len = ULONG_MAX; 1164 1165 if (argc != 2 && argc != 4) 1166 return -EINVAL; 1167 1168 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1169 return -EINVAL; 1170 1171 if (argc > 3) { 1172 if (strcmp(argv[2], "-") && 1173 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1) 1174 return -EINVAL; 1175 if (strcmp(argv[3], "-") && 1176 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1) 1177 return -EINVAL; 1178 } 1179 1180 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear, 1181 result, maxlen); 1182 } 1183 1184 static int message_stats_set_aux(struct mapped_device *md, 1185 unsigned argc, char **argv) 1186 { 1187 int id; 1188 char dummy; 1189 1190 if (argc != 3) 1191 return -EINVAL; 1192 1193 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1194 return -EINVAL; 1195 1196 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]); 1197 } 1198 1199 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv, 1200 char *result, unsigned maxlen) 1201 { 1202 int r; 1203 1204 /* All messages here must start with '@' */ 1205 if (!strcasecmp(argv[0], "@stats_create")) 1206 r = message_stats_create(md, argc, argv, result, maxlen); 1207 else if (!strcasecmp(argv[0], "@stats_delete")) 1208 r = message_stats_delete(md, argc, argv); 1209 else if (!strcasecmp(argv[0], "@stats_clear")) 1210 r = message_stats_clear(md, argc, argv); 1211 else if (!strcasecmp(argv[0], "@stats_list")) 1212 r = message_stats_list(md, argc, argv, result, maxlen); 1213 else if (!strcasecmp(argv[0], "@stats_print")) 1214 r = message_stats_print(md, argc, argv, false, result, maxlen); 1215 else if (!strcasecmp(argv[0], "@stats_print_clear")) 1216 r = message_stats_print(md, argc, argv, true, result, maxlen); 1217 else if (!strcasecmp(argv[0], "@stats_set_aux")) 1218 r = message_stats_set_aux(md, argc, argv); 1219 else 1220 return 2; /* this wasn't a stats message */ 1221 1222 if (r == -EINVAL) 1223 DMCRIT("Invalid parameters for message %s", argv[0]); 1224 1225 return r; 1226 } 1227 1228 int __init dm_statistics_init(void) 1229 { 1230 shared_memory_amount = 0; 1231 dm_stat_need_rcu_barrier = 0; 1232 return 0; 1233 } 1234 1235 void dm_statistics_exit(void) 1236 { 1237 if (dm_stat_need_rcu_barrier) 1238 rcu_barrier(); 1239 if (WARN_ON(shared_memory_amount)) 1240 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount); 1241 } 1242 1243 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO); 1244 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics"); 1245