git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/util.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * random utiility code, for bcache but in theory not specific to bcache
   4  *
   5  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   6  * Copyright 2012 Google, Inc.
   7  */
   8
   9 #include <linux/bio.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/console.h>
  12 #include <linux/ctype.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/eytzinger.h>
  15 #include <linux/freezer.h>
  16 #include <linux/kthread.h>
  17 #include <linux/log2.h>
  18 #include <linux/math64.h>
  19 #include <linux/percpu.h>
  20 #include <linux/preempt.h>
  21 #include <linux/random.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/string.h>
  24 #include <linux/types.h>
  25 #include <linux/sched/clock.h>
  26 #include <linux/mean_and_variance.h>
  27
  28 #include "util.h"
  29
  30 static const char si_units[] = "?kMGTPEZY";
  31
  32 /* string_get_size units: */
  33 static const char *const units_2[] = {
  34         "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"
  35 };
  36 static const char *const units_10[] = {
  37         "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"
  38 };
  39
  40 static int parse_u64(const char *cp, u64 *res)
  41 {
  42         const char *start = cp;
  43         u64 v = 0;
  44
  45         if (!isdigit(*cp))
  46                 return -EINVAL;
  47
  48         do {
  49                 if (v > U64_MAX / 10)
  50                         return -ERANGE;
  51                 v *= 10;
  52                 if (v > U64_MAX - (*cp - '0'))
  53                         return -ERANGE;
  54                 v += *cp - '0';
  55                 cp++;
  56         } while (isdigit(*cp));
  57
  58         *res = v;
  59         return cp - start;
  60 }
  61
  62 static int bch2_pow(u64 n, u64 p, u64 *res)
  63 {
  64         *res = 1;
  65
  66         while (p--) {
  67                 if (*res > div_u64(U64_MAX, n))
  68                         return -ERANGE;
  69                 *res *= n;
  70         }
  71         return 0;
  72 }
  73
  74 static int parse_unit_suffix(const char *cp, u64 *res)
  75 {
  76         const char *start = cp;
  77         u64 base = 1024;
  78         unsigned u;
  79         int ret;
  80
  81         if (*cp == ' ')
  82                 cp++;
  83
  84         for (u = 1; u < strlen(si_units); u++)
  85                 if (*cp == si_units[u]) {
  86                         cp++;
  87                         goto got_unit;
  88                 }
  89
  90         for (u = 0; u < ARRAY_SIZE(units_2); u++)
  91                 if (!strncmp(cp, units_2[u], strlen(units_2[u]))) {
  92                         cp += strlen(units_2[u]);
  93                         goto got_unit;
  94                 }
  95
  96         for (u = 0; u < ARRAY_SIZE(units_10); u++)
  97                 if (!strncmp(cp, units_10[u], strlen(units_10[u]))) {
  98                         cp += strlen(units_10[u]);
  99                         base = 1000;
 100                         goto got_unit;
 101                 }
 102
 103         *res = 1;
 104         return 0;
 105 got_unit:
 106         ret = bch2_pow(base, u, res);
 107         if (ret)
 108                 return ret;
 109
 110         return cp - start;
 111 }
 112
 113 #define parse_or_ret(cp, _f)                    \
 114 do {                                            \
 115         int _ret = _f;                          \
 116         if (_ret < 0)                           \
 117                 return _ret;                    \
 118         cp += _ret;                             \
 119 } while (0)
 120
 121 static int __bch2_strtou64_h(const char *cp, u64 *res)
 122 {
 123         const char *start = cp;
 124         u64 v = 0, b, f_n = 0, f_d = 1;
 125         int ret;
 126
 127         parse_or_ret(cp, parse_u64(cp, &v));
 128
 129         if (*cp == '.') {
 130                 cp++;
 131                 ret = parse_u64(cp, &f_n);
 132                 if (ret < 0)
 133                         return ret;
 134                 cp += ret;
 135
 136                 ret = bch2_pow(10, ret, &f_d);
 137                 if (ret)
 138                         return ret;
 139         }
 140
 141         parse_or_ret(cp, parse_unit_suffix(cp, &b));
 142
 143         if (v > div_u64(U64_MAX, b))
 144                 return -ERANGE;
 145         v *= b;
 146
 147         if (f_n > div_u64(U64_MAX, b))
 148                 return -ERANGE;
 149
 150         f_n = div_u64(f_n * b, f_d);
 151         if (v + f_n < v)
 152                 return -ERANGE;
 153         v += f_n;
 154
 155         *res = v;
 156         return cp - start;
 157 }
 158
 159 static int __bch2_strtoh(const char *cp, u64 *res,
 160                          u64 t_max, bool t_signed)
 161 {
 162         bool positive = *cp != '-';
 163         u64 v = 0;
 164
 165         if (*cp == '+' || *cp == '-')
 166                 cp++;
 167
 168         parse_or_ret(cp, __bch2_strtou64_h(cp, &v));
 169
 170         if (*cp == '\n')
 171                 cp++;
 172         if (*cp)
 173                 return -EINVAL;
 174
 175         if (positive) {
 176                 if (v > t_max)
 177                         return -ERANGE;
 178         } else {
 179                 if (v && !t_signed)
 180                         return -ERANGE;
 181
 182                 if (v > t_max + 1)
 183                         return -ERANGE;
 184                 v = -v;
 185         }
 186
 187         *res = v;
 188         return 0;
 189 }
 190
 191 #define STRTO_H(name, type)                                     \
 192 int bch2_ ## name ## _h(const char *cp, type *res)              \
 193 {                                                               \
 194         u64 v = 0;                                              \
 195         int ret = __bch2_strtoh(cp, &v, ANYSINT_MAX(type),      \
 196                         ANYSINT_MAX(type) != ((type) ~0ULL));   \
 197         *res = v;                                               \
 198         return ret;                                             \
 199 }
 200
 201 STRTO_H(strtoint, int)
 202 STRTO_H(strtouint, unsigned int)
 203 STRTO_H(strtoll, long long)
 204 STRTO_H(strtoull, unsigned long long)
 205 STRTO_H(strtou64, u64)
 206
 207 u64 bch2_read_flag_list(char *opt, const char * const list[])
 208 {
 209         u64 ret = 0;
 210         char *p, *s, *d = kstrdup(opt, GFP_KERNEL);
 211
 212         if (!d)
 213                 return -ENOMEM;
 214
 215         s = strim(d);
 216
 217         while ((p = strsep(&s, ","))) {
 218                 int flag = match_string(list, -1, p);
 219
 220                 if (flag < 0) {
 221                         ret = -1;
 222                         break;
 223                 }
 224
 225                 ret |= 1 << flag;
 226         }
 227
 228         kfree(d);
 229
 230         return ret;
 231 }
 232
 233 bool bch2_is_zero(const void *_p, size_t n)
 234 {
 235         const char *p = _p;
 236         size_t i;
 237
 238         for (i = 0; i < n; i++)
 239                 if (p[i])
 240                         return false;
 241         return true;
 242 }
 243
 244 void bch2_prt_u64_base2_nbits(struct printbuf *out, u64 v, unsigned nr_bits)
 245 {
 246         while (nr_bits)
 247                 prt_char(out, '0' + ((v >> --nr_bits) & 1));
 248 }
 249
 250 void bch2_prt_u64_base2(struct printbuf *out, u64 v)
 251 {
 252         bch2_prt_u64_base2_nbits(out, v, fls64(v) ?: 1);
 253 }
 254
 255 void bch2_print_string_as_lines(const char *prefix, const char *lines)
 256 {
 257         const char *p;
 258
 259         if (!lines) {
 260                 printk("%s (null)\n", prefix);
 261                 return;
 262         }
 263
 264         console_lock();
 265         while (1) {
 266                 p = strchrnul(lines, '\n');
 267                 printk("%s%.*s\n", prefix, (int) (p - lines), lines);
 268                 if (!*p)
 269                         break;
 270                 lines = p + 1;
 271         }
 272         console_unlock();
 273 }
 274
 275 int bch2_save_backtrace(bch_stacktrace *stack, struct task_struct *task, unsigned skipnr,
 276                         gfp_t gfp)
 277 {
 278 #ifdef CONFIG_STACKTRACE
 279         unsigned nr_entries = 0;
 280
 281         stack->nr = 0;
 282         int ret = darray_make_room_gfp(stack, 32, gfp);
 283         if (ret)
 284                 return ret;
 285
 286         if (!down_read_trylock(&task->signal->exec_update_lock))
 287                 return -1;
 288
 289         do {
 290                 nr_entries = stack_trace_save_tsk(task, stack->data, stack->size, skipnr + 1);
 291         } while (nr_entries == stack->size &&
 292                  !(ret = darray_make_room(stack, stack->size * 2)));
 293
 294         stack->nr = nr_entries;
 295         up_read(&task->signal->exec_update_lock);
 296
 297         return ret;
 298 #else
 299         return 0;
 300 #endif
 301 }
 302
 303 void bch2_prt_backtrace(struct printbuf *out, bch_stacktrace *stack)
 304 {
 305         darray_for_each(*stack, i) {
 306                 prt_printf(out, "[<0>] %pB", (void *) *i);
 307                 prt_newline(out);
 308         }
 309 }
 310
 311 int bch2_prt_task_backtrace(struct printbuf *out, struct task_struct *task, unsigned skipnr, gfp_t gfp)
 312 {
 313         bch_stacktrace stack = { 0 };
 314         int ret = bch2_save_backtrace(&stack, task, skipnr + 1, gfp);
 315
 316         bch2_prt_backtrace(out, &stack);
 317         darray_exit(&stack);
 318         return ret;
 319 }
 320
 321 #ifndef __KERNEL__
 322 #include <time.h>
 323 void bch2_prt_datetime(struct printbuf *out, time64_t sec)
 324 {
 325         time_t t = sec;
 326         char buf[64];
 327         ctime_r(&t, buf);
 328         strim(buf);
 329         prt_str(out, buf);
 330 }
 331 #else
 332 void bch2_prt_datetime(struct printbuf *out, time64_t sec)
 333 {
 334         char buf[64];
 335         snprintf(buf, sizeof(buf), "%ptT", &sec);
 336         prt_u64(out, sec);
 337 }
 338 #endif
 339
 340 void bch2_pr_time_units(struct printbuf *out, u64 ns)
 341 {
 342         const struct time_unit *u = pick_time_units(ns);
 343
 344         prt_printf(out, "%llu %s", div_u64(ns, u->nsecs), u->name);
 345 }
 346
 347 static void bch2_pr_time_units_aligned(struct printbuf *out, u64 ns)
 348 {
 349         const struct time_unit *u = pick_time_units(ns);
 350
 351         prt_printf(out, "%llu ", div64_u64(ns, u->nsecs));
 352         prt_tab_rjust(out);
 353         prt_printf(out, "%s", u->name);
 354 }
 355
 356 static inline void pr_name_and_units(struct printbuf *out, const char *name, u64 ns)
 357 {
 358         prt_str(out, name);
 359         prt_tab(out);
 360         bch2_pr_time_units_aligned(out, ns);
 361         prt_newline(out);
 362 }
 363
 364 #define TABSTOP_SIZE 12
 365
 366 void bch2_time_stats_to_text(struct printbuf *out, struct time_stats *stats)
 367 {
 368         struct quantiles *quantiles = time_stats_to_quantiles(stats);
 369         s64 f_mean = 0, d_mean = 0;
 370         u64 f_stddev = 0, d_stddev = 0;
 371
 372         if (stats->buffer) {
 373                 int cpu;
 374
 375                 spin_lock_irq(&stats->lock);
 376                 for_each_possible_cpu(cpu)
 377                         __time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu));
 378                 spin_unlock_irq(&stats->lock);
 379         }
 380
 381         /*
 382          * avoid divide by zero
 383          */
 384         if (stats->freq_stats.n) {
 385                 f_mean = mean_and_variance_get_mean(stats->freq_stats);
 386                 f_stddev = mean_and_variance_get_stddev(stats->freq_stats);
 387                 d_mean = mean_and_variance_get_mean(stats->duration_stats);
 388                 d_stddev = mean_and_variance_get_stddev(stats->duration_stats);
 389         }
 390
 391         printbuf_tabstop_push(out, out->indent + TABSTOP_SIZE);
 392         prt_printf(out, "count:");
 393         prt_tab(out);
 394         prt_printf(out, "%llu ",
 395                          stats->duration_stats.n);
 396         printbuf_tabstop_pop(out);
 397         prt_newline(out);
 398
 399         printbuf_tabstops_reset(out);
 400
 401         printbuf_tabstop_push(out, out->indent + 20);
 402         printbuf_tabstop_push(out, TABSTOP_SIZE + 2);
 403         printbuf_tabstop_push(out, 0);
 404         printbuf_tabstop_push(out, TABSTOP_SIZE + 2);
 405
 406         prt_tab(out);
 407         prt_printf(out, "since mount");
 408         prt_tab_rjust(out);
 409         prt_tab(out);
 410         prt_printf(out, "recent");
 411         prt_tab_rjust(out);
 412         prt_newline(out);
 413
 414         printbuf_tabstops_reset(out);
 415         printbuf_tabstop_push(out, out->indent + 20);
 416         printbuf_tabstop_push(out, TABSTOP_SIZE);
 417         printbuf_tabstop_push(out, 2);
 418         printbuf_tabstop_push(out, TABSTOP_SIZE);
 419
 420         prt_printf(out, "duration of events");
 421         prt_newline(out);
 422         printbuf_indent_add(out, 2);
 423
 424         pr_name_and_units(out, "min:", stats->min_duration);
 425         pr_name_and_units(out, "max:", stats->max_duration);
 426         pr_name_and_units(out, "total:", stats->total_duration);
 427
 428         prt_printf(out, "mean:");
 429         prt_tab(out);
 430         bch2_pr_time_units_aligned(out, d_mean);
 431         prt_tab(out);
 432         bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT));
 433         prt_newline(out);
 434
 435         prt_printf(out, "stddev:");
 436         prt_tab(out);
 437         bch2_pr_time_units_aligned(out, d_stddev);
 438         prt_tab(out);
 439         bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT));
 440
 441         printbuf_indent_sub(out, 2);
 442         prt_newline(out);
 443
 444         prt_printf(out, "time between events");
 445         prt_newline(out);
 446         printbuf_indent_add(out, 2);
 447
 448         pr_name_and_units(out, "min:", stats->min_freq);
 449         pr_name_and_units(out, "max:", stats->max_freq);
 450
 451         prt_printf(out, "mean:");
 452         prt_tab(out);
 453         bch2_pr_time_units_aligned(out, f_mean);
 454         prt_tab(out);
 455         bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT));
 456         prt_newline(out);
 457
 458         prt_printf(out, "stddev:");
 459         prt_tab(out);
 460         bch2_pr_time_units_aligned(out, f_stddev);
 461         prt_tab(out);
 462         bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT));
 463
 464         printbuf_indent_sub(out, 2);
 465         prt_newline(out);
 466
 467         printbuf_tabstops_reset(out);
 468
 469         if (quantiles) {
 470                 int i = eytzinger0_first(NR_QUANTILES);
 471                 const struct time_unit *u =
 472                         pick_time_units(quantiles->entries[i].m);
 473                 u64 last_q = 0;
 474
 475                 prt_printf(out, "quantiles (%s):\t", u->name);
 476                 eytzinger0_for_each(i, NR_QUANTILES) {
 477                         bool is_last = eytzinger0_next(i, NR_QUANTILES) == -1;
 478
 479                         u64 q = max(quantiles->entries[i].m, last_q);
 480                         prt_printf(out, "%llu ", div_u64(q, u->nsecs));
 481                         if (is_last)
 482                                 prt_newline(out);
 483                         last_q = q;
 484                 }
 485         }
 486 }
 487
 488 /* ratelimit: */
 489
 490 /**
 491  * bch2_ratelimit_delay() - return how long to delay until the next time to do
 492  *              some work
 493  * @d:          the struct bch_ratelimit to update
 494  * Returns:     the amount of time to delay by, in jiffies
 495  */
 496 u64 bch2_ratelimit_delay(struct bch_ratelimit *d)
 497 {
 498         u64 now = local_clock();
 499
 500         return time_after64(d->next, now)
 501                 ? nsecs_to_jiffies(d->next - now)
 502                 : 0;
 503 }
 504
 505 /**
 506  * bch2_ratelimit_increment() - increment @d by the amount of work done
 507  * @d:          the struct bch_ratelimit to update
 508  * @done:       the amount of work done, in arbitrary units
 509  */
 510 void bch2_ratelimit_increment(struct bch_ratelimit *d, u64 done)
 511 {
 512         u64 now = local_clock();
 513
 514         d->next += div_u64(done * NSEC_PER_SEC, d->rate);
 515
 516         if (time_before64(now + NSEC_PER_SEC, d->next))
 517                 d->next = now + NSEC_PER_SEC;
 518
 519         if (time_after64(now - NSEC_PER_SEC * 2, d->next))
 520                 d->next = now - NSEC_PER_SEC * 2;
 521 }
 522
 523 /* pd controller: */
 524
 525 /*
 526  * Updates pd_controller. Attempts to scale inputed values to units per second.
 527  * @target: desired value
 528  * @actual: current value
 529  *
 530  * @sign: 1 or -1; 1 if increasing the rate makes actual go up, -1 if increasing
 531  * it makes actual go down.
 532  */
 533 void bch2_pd_controller_update(struct bch_pd_controller *pd,
 534                               s64 target, s64 actual, int sign)
 535 {
 536         s64 proportional, derivative, change;
 537
 538         unsigned long seconds_since_update = (jiffies - pd->last_update) / HZ;
 539
 540         if (seconds_since_update == 0)
 541                 return;
 542
 543         pd->last_update = jiffies;
 544
 545         proportional = actual - target;
 546         proportional *= seconds_since_update;
 547         proportional = div_s64(proportional, pd->p_term_inverse);
 548
 549         derivative = actual - pd->last_actual;
 550         derivative = div_s64(derivative, seconds_since_update);
 551         derivative = ewma_add(pd->smoothed_derivative, derivative,
 552                               (pd->d_term / seconds_since_update) ?: 1);
 553         derivative = derivative * pd->d_term;
 554         derivative = div_s64(derivative, pd->p_term_inverse);
 555
 556         change = proportional + derivative;
 557
 558         /* Don't increase rate if not keeping up */
 559         if (change > 0 &&
 560             pd->backpressure &&
 561             time_after64(local_clock(),
 562                          pd->rate.next + NSEC_PER_MSEC))
 563                 change = 0;
 564
 565         change *= (sign * -1);
 566
 567         pd->rate.rate = clamp_t(s64, (s64) pd->rate.rate + change,
 568                                 1, UINT_MAX);
 569
 570         pd->last_actual         = actual;
 571         pd->last_derivative     = derivative;
 572         pd->last_proportional   = proportional;
 573         pd->last_change         = change;
 574         pd->last_target         = target;
 575 }
 576
 577 void bch2_pd_controller_init(struct bch_pd_controller *pd)
 578 {
 579         pd->rate.rate           = 1024;
 580         pd->last_update         = jiffies;
 581         pd->p_term_inverse      = 6000;
 582         pd->d_term              = 30;
 583         pd->d_smooth            = pd->d_term;
 584         pd->backpressure        = 1;
 585 }
 586
 587 void bch2_pd_controller_debug_to_text(struct printbuf *out, struct bch_pd_controller *pd)
 588 {
 589         if (!out->nr_tabstops)
 590                 printbuf_tabstop_push(out, 20);
 591
 592         prt_printf(out, "rate:");
 593         prt_tab(out);
 594         prt_human_readable_s64(out, pd->rate.rate);
 595         prt_newline(out);
 596
 597         prt_printf(out, "target:");
 598         prt_tab(out);
 599         prt_human_readable_u64(out, pd->last_target);
 600         prt_newline(out);
 601
 602         prt_printf(out, "actual:");
 603         prt_tab(out);
 604         prt_human_readable_u64(out, pd->last_actual);
 605         prt_newline(out);
 606
 607         prt_printf(out, "proportional:");
 608         prt_tab(out);
 609         prt_human_readable_s64(out, pd->last_proportional);
 610         prt_newline(out);
 611
 612         prt_printf(out, "derivative:");
 613         prt_tab(out);
 614         prt_human_readable_s64(out, pd->last_derivative);
 615         prt_newline(out);
 616
 617         prt_printf(out, "change:");
 618         prt_tab(out);
 619         prt_human_readable_s64(out, pd->last_change);
 620         prt_newline(out);
 621
 622         prt_printf(out, "next io:");
 623         prt_tab(out);
 624         prt_printf(out, "%llims", div64_s64(pd->rate.next - local_clock(), NSEC_PER_MSEC));
 625         prt_newline(out);
 626 }
 627
 628 /* misc: */
 629
 630 void bch2_bio_map(struct bio *bio, void *base, size_t size)
 631 {
 632         while (size) {
 633                 struct page *page = is_vmalloc_addr(base)
 634                                 ? vmalloc_to_page(base)
 635                                 : virt_to_page(base);
 636                 unsigned offset = offset_in_page(base);
 637                 unsigned len = min_t(size_t, PAGE_SIZE - offset, size);
 638
 639                 BUG_ON(!bio_add_page(bio, page, len, offset));
 640                 size -= len;
 641                 base += len;
 642         }
 643 }
 644
 645 int bch2_bio_alloc_pages(struct bio *bio, size_t size, gfp_t gfp_mask)
 646 {
 647         while (size) {
 648                 struct page *page = alloc_pages(gfp_mask, 0);
 649                 unsigned len = min_t(size_t, PAGE_SIZE, size);
 650
 651                 if (!page)
 652                         return -ENOMEM;
 653
 654                 if (unlikely(!bio_add_page(bio, page, len, 0))) {
 655                         __free_page(page);
 656                         break;
 657                 }
 658
 659                 size -= len;
 660         }
 661
 662         return 0;
 663 }
 664
 665 size_t bch2_rand_range(size_t max)
 666 {
 667         size_t rand;
 668
 669         if (!max)
 670                 return 0;
 671
 672         do {
 673                 rand = get_random_long();
 674                 rand &= roundup_pow_of_two(max) - 1;
 675         } while (rand >= max);
 676
 677         return rand;
 678 }
 679
 680 void memcpy_to_bio(struct bio *dst, struct bvec_iter dst_iter, const void *src)
 681 {
 682         struct bio_vec bv;
 683         struct bvec_iter iter;
 684
 685         __bio_for_each_segment(bv, dst, iter, dst_iter) {
 686                 void *dstp = kmap_local_page(bv.bv_page);
 687
 688                 memcpy(dstp + bv.bv_offset, src, bv.bv_len);
 689                 kunmap_local(dstp);
 690
 691                 src += bv.bv_len;
 692         }
 693 }
 694
 695 void memcpy_from_bio(void *dst, struct bio *src, struct bvec_iter src_iter)
 696 {
 697         struct bio_vec bv;
 698         struct bvec_iter iter;
 699
 700         __bio_for_each_segment(bv, src, iter, src_iter) {
 701                 void *srcp = kmap_local_page(bv.bv_page);
 702
 703                 memcpy(dst, srcp + bv.bv_offset, bv.bv_len);
 704                 kunmap_local(srcp);
 705
 706                 dst += bv.bv_len;
 707         }
 708 }
 709
 710 #if 0
 711 void eytzinger1_test(void)
 712 {
 713         unsigned inorder, eytz, size;
 714
 715         pr_info("1 based eytzinger test:");
 716
 717         for (size = 2;
 718              size < 65536;
 719              size++) {
 720                 unsigned extra = eytzinger1_extra(size);
 721
 722                 if (!(size % 4096))
 723                         pr_info("tree size %u", size);
 724
 725                 BUG_ON(eytzinger1_prev(0, size) != eytzinger1_last(size));
 726                 BUG_ON(eytzinger1_next(0, size) != eytzinger1_first(size));
 727
 728                 BUG_ON(eytzinger1_prev(eytzinger1_first(size), size)    != 0);
 729                 BUG_ON(eytzinger1_next(eytzinger1_last(size), size)     != 0);
 730
 731                 inorder = 1;
 732                 eytzinger1_for_each(eytz, size) {
 733                         BUG_ON(__inorder_to_eytzinger1(inorder, size, extra) != eytz);
 734                         BUG_ON(__eytzinger1_to_inorder(eytz, size, extra) != inorder);
 735                         BUG_ON(eytz != eytzinger1_last(size) &&
 736                                eytzinger1_prev(eytzinger1_next(eytz, size), size) != eytz);
 737
 738                         inorder++;
 739                 }
 740         }
 741 }
 742
 743 void eytzinger0_test(void)
 744 {
 745
 746         unsigned inorder, eytz, size;
 747
 748         pr_info("0 based eytzinger test:");
 749
 750         for (size = 1;
 751              size < 65536;
 752              size++) {
 753                 unsigned extra = eytzinger0_extra(size);
 754
 755                 if (!(size % 4096))
 756                         pr_info("tree size %u", size);
 757
 758                 BUG_ON(eytzinger0_prev(-1, size) != eytzinger0_last(size));
 759                 BUG_ON(eytzinger0_next(-1, size) != eytzinger0_first(size));
 760
 761                 BUG_ON(eytzinger0_prev(eytzinger0_first(size), size)    != -1);
 762                 BUG_ON(eytzinger0_next(eytzinger0_last(size), size)     != -1);
 763
 764                 inorder = 0;
 765                 eytzinger0_for_each(eytz, size) {
 766                         BUG_ON(__inorder_to_eytzinger0(inorder, size, extra) != eytz);
 767                         BUG_ON(__eytzinger0_to_inorder(eytz, size, extra) != inorder);
 768                         BUG_ON(eytz != eytzinger0_last(size) &&
 769                                eytzinger0_prev(eytzinger0_next(eytz, size), size) != eytz);
 770
 771                         inorder++;
 772                 }
 773         }
 774 }
 775
 776 static inline int cmp_u16(const void *_l, const void *_r, size_t size)
 777 {
 778         const u16 *l = _l, *r = _r;
 779
 780         return (*l > *r) - (*r - *l);
 781 }
 782
 783 static void eytzinger0_find_test_val(u16 *test_array, unsigned nr, u16 search)
 784 {
 785         int i, c1 = -1, c2 = -1;
 786         ssize_t r;
 787
 788         r = eytzinger0_find_le(test_array, nr,
 789                                sizeof(test_array[0]),
 790                                cmp_u16, &search);
 791         if (r >= 0)
 792                 c1 = test_array[r];
 793
 794         for (i = 0; i < nr; i++)
 795                 if (test_array[i] <= search && test_array[i] > c2)
 796                         c2 = test_array[i];
 797
 798         if (c1 != c2) {
 799                 eytzinger0_for_each(i, nr)
 800                         pr_info("[%3u] = %12u", i, test_array[i]);
 801                 pr_info("find_le(%2u) -> [%2zi] = %2i should be %2i",
 802                         i, r, c1, c2);
 803         }
 804 }
 805
 806 void eytzinger0_find_test(void)
 807 {
 808         unsigned i, nr, allocated = 1 << 12;
 809         u16 *test_array = kmalloc_array(allocated, sizeof(test_array[0]), GFP_KERNEL);
 810
 811         for (nr = 1; nr < allocated; nr++) {
 812                 pr_info("testing %u elems", nr);
 813
 814                 get_random_bytes(test_array, nr * sizeof(test_array[0]));
 815                 eytzinger0_sort(test_array, nr, sizeof(test_array[0]), cmp_u16, NULL);
 816
 817                 /* verify array is sorted correctly: */
 818                 eytzinger0_for_each(i, nr)
 819                         BUG_ON(i != eytzinger0_last(nr) &&
 820                                test_array[i] > test_array[eytzinger0_next(i, nr)]);
 821
 822                 for (i = 0; i < U16_MAX; i += 1 << 12)
 823                         eytzinger0_find_test_val(test_array, nr, i);
 824
 825                 for (i = 0; i < nr; i++) {
 826                         eytzinger0_find_test_val(test_array, nr, test_array[i] - 1);
 827                         eytzinger0_find_test_val(test_array, nr, test_array[i]);
 828                         eytzinger0_find_test_val(test_array, nr, test_array[i] + 1);
 829                 }
 830         }
 831
 832         kfree(test_array);
 833 }
 834 #endif
 835
 836 /*
 837  * Accumulate percpu counters onto one cpu's copy - only valid when access
 838  * against any percpu counter is guarded against
 839  */
 840 u64 *bch2_acc_percpu_u64s(u64 __percpu *p, unsigned nr)
 841 {
 842         u64 *ret;
 843         int cpu;
 844
 845         /* access to pcpu vars has to be blocked by other locking */
 846         preempt_disable();
 847         ret = this_cpu_ptr(p);
 848         preempt_enable();
 849
 850         for_each_possible_cpu(cpu) {
 851                 u64 *i = per_cpu_ptr(p, cpu);
 852
 853                 if (i != ret) {
 854                         acc_u64s(ret, i, nr);
 855                         memset(i, 0, nr * sizeof(u64));
 856                 }
 857         }
 858
 859         return ret;
 860 }
 861
 862 void bch2_darray_str_exit(darray_str *d)
 863 {
 864         darray_for_each(*d, i)
 865                 kfree(*i);
 866         darray_exit(d);
 867 }
 868
 869 int bch2_split_devs(const char *_dev_name, darray_str *ret)
 870 {
 871         darray_init(ret);
 872
 873         char *dev_name, *s, *orig;
 874
 875         dev_name = orig = kstrdup(_dev_name, GFP_KERNEL);
 876         if (!dev_name)
 877                 return -ENOMEM;
 878
 879         while ((s = strsep(&dev_name, ":"))) {
 880                 char *p = kstrdup(s, GFP_KERNEL);
 881                 if (!p)
 882                         goto err;
 883
 884                 if (darray_push(ret, p)) {
 885                         kfree(p);
 886                         goto err;
 887                 }
 888         }
 889
 890         kfree(orig);
 891         return 0;
 892 err:
 893         bch2_darray_str_exit(ret);
 894         kfree(orig);
 895         return -ENOMEM;
 896 }