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1// SPDX-License-Identifier: GPL-2.02/*3 * random utility code, for bcache but in theory not specific to bcache4 *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/freezer.h>15#include <linux/kthread.h>16#include <linux/log2.h>17#include <linux/math64.h>18#include <linux/percpu.h>19#include <linux/preempt.h>20#include <linux/random.h>21#include <linux/seq_file.h>22#include <linux/string.h>23#include <linux/types.h>24#include <linux/sched/clock.h>25 26#include "eytzinger.h"27#include "mean_and_variance.h"28#include "util.h"29 30static const char si_units[] = "?kMGTPEZY";31 32/* string_get_size units: */33static const char *const units_2[] = {34 "B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"35};36static const char *const units_10[] = {37 "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"38};39 40static 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 62static int bch2_pow(u64 n, u64 p, u64 *res)63{64 *res = 1;65 66 while (p--) {67 if (*res > div64_u64(U64_MAX, n))68 return -ERANGE;69 *res *= n;70 }71 return 0;72}73 74static 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;105got_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) \114do { \115 int _ret = _f; \116 if (_ret < 0) \117 return _ret; \118 cp += _ret; \119} while (0)120 121static 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 > div64_u64(U64_MAX, b))144 return -ERANGE;145 v *= b;146 147 if (f_n > div64_u64(U64_MAX, b))148 return -ERANGE;149 150 f_n = div64_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 159static 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) \192int 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 201STRTO_H(strtoint, int)202STRTO_H(strtouint, unsigned int)203STRTO_H(strtoll, long long)204STRTO_H(strtoull, unsigned long long)205STRTO_H(strtou64, u64)206 207u64 bch2_read_flag_list(const 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 |= BIT_ULL(flag);226 }227 228 kfree(d);229 230 return ret;231}232 233bool 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 244void 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 250void bch2_prt_u64_base2(struct printbuf *out, u64 v)251{252 bch2_prt_u64_base2_nbits(out, v, fls64(v) ?: 1);253}254 255static void __bch2_print_string_as_lines(const char *prefix, const char *lines,256 bool nonblocking)257{258 bool locked = false;259 const char *p;260 261 if (!lines) {262 printk("%s (null)\n", prefix);263 return;264 }265 266 if (!nonblocking) {267 console_lock();268 locked = true;269 } else {270 locked = console_trylock();271 }272 273 while (1) {274 p = strchrnul(lines, '\n');275 printk("%s%.*s\n", prefix, (int) (p - lines), lines);276 if (!*p)277 break;278 lines = p + 1;279 }280 if (locked)281 console_unlock();282}283 284void bch2_print_string_as_lines(const char *prefix, const char *lines)285{286 return __bch2_print_string_as_lines(prefix, lines, false);287}288 289void bch2_print_string_as_lines_nonblocking(const char *prefix, const char *lines)290{291 return __bch2_print_string_as_lines(prefix, lines, true);292}293 294int bch2_save_backtrace(bch_stacktrace *stack, struct task_struct *task, unsigned skipnr,295 gfp_t gfp)296{297#ifdef CONFIG_STACKTRACE298 unsigned nr_entries = 0;299 300 stack->nr = 0;301 int ret = darray_make_room_gfp(stack, 32, gfp);302 if (ret)303 return ret;304 305 if (!down_read_trylock(&task->signal->exec_update_lock))306 return -1;307 308 do {309 nr_entries = stack_trace_save_tsk(task, stack->data, stack->size, skipnr + 1);310 } while (nr_entries == stack->size &&311 !(ret = darray_make_room_gfp(stack, stack->size * 2, gfp)));312 313 stack->nr = nr_entries;314 up_read(&task->signal->exec_update_lock);315 316 return ret;317#else318 return 0;319#endif320}321 322void bch2_prt_backtrace(struct printbuf *out, bch_stacktrace *stack)323{324 darray_for_each(*stack, i) {325 prt_printf(out, "[<0>] %pB", (void *) *i);326 prt_newline(out);327 }328}329 330int bch2_prt_task_backtrace(struct printbuf *out, struct task_struct *task, unsigned skipnr, gfp_t gfp)331{332 bch_stacktrace stack = { 0 };333 int ret = bch2_save_backtrace(&stack, task, skipnr + 1, gfp);334 335 bch2_prt_backtrace(out, &stack);336 darray_exit(&stack);337 return ret;338}339 340#ifndef __KERNEL__341#include <time.h>342void bch2_prt_datetime(struct printbuf *out, time64_t sec)343{344 time_t t = sec;345 char buf[64];346 ctime_r(&t, buf);347 strim(buf);348 prt_str(out, buf);349}350#else351void bch2_prt_datetime(struct printbuf *out, time64_t sec)352{353 char buf[64];354 snprintf(buf, sizeof(buf), "%ptT", &sec);355 prt_u64(out, sec);356}357#endif358 359void bch2_pr_time_units(struct printbuf *out, u64 ns)360{361 const struct time_unit *u = bch2_pick_time_units(ns);362 363 prt_printf(out, "%llu %s", div64_u64(ns, u->nsecs), u->name);364}365 366static void bch2_pr_time_units_aligned(struct printbuf *out, u64 ns)367{368 const struct time_unit *u = bch2_pick_time_units(ns);369 370 prt_printf(out, "%llu \r%s", div64_u64(ns, u->nsecs), u->name);371}372 373static inline void pr_name_and_units(struct printbuf *out, const char *name, u64 ns)374{375 prt_printf(out, "%s\t", name);376 bch2_pr_time_units_aligned(out, ns);377 prt_newline(out);378}379 380#define TABSTOP_SIZE 12381 382void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats)383{384 struct quantiles *quantiles = time_stats_to_quantiles(stats);385 s64 f_mean = 0, d_mean = 0;386 u64 f_stddev = 0, d_stddev = 0;387 388 if (stats->buffer) {389 int cpu;390 391 spin_lock_irq(&stats->lock);392 for_each_possible_cpu(cpu)393 __bch2_time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu));394 spin_unlock_irq(&stats->lock);395 }396 397 /*398 * avoid divide by zero399 */400 if (stats->freq_stats.n) {401 f_mean = mean_and_variance_get_mean(stats->freq_stats);402 f_stddev = mean_and_variance_get_stddev(stats->freq_stats);403 d_mean = mean_and_variance_get_mean(stats->duration_stats);404 d_stddev = mean_and_variance_get_stddev(stats->duration_stats);405 }406 407 printbuf_tabstop_push(out, out->indent + TABSTOP_SIZE);408 prt_printf(out, "count:\t%llu\n", stats->duration_stats.n);409 printbuf_tabstop_pop(out);410 411 printbuf_tabstops_reset(out);412 413 printbuf_tabstop_push(out, out->indent + 20);414 printbuf_tabstop_push(out, TABSTOP_SIZE + 2);415 printbuf_tabstop_push(out, 0);416 printbuf_tabstop_push(out, TABSTOP_SIZE + 2);417 418 prt_printf(out, "\tsince mount\r\trecent\r\n");419 420 printbuf_tabstops_reset(out);421 printbuf_tabstop_push(out, out->indent + 20);422 printbuf_tabstop_push(out, TABSTOP_SIZE);423 printbuf_tabstop_push(out, 2);424 printbuf_tabstop_push(out, TABSTOP_SIZE);425 426 prt_printf(out, "duration of events\n");427 printbuf_indent_add(out, 2);428 429 pr_name_and_units(out, "min:", stats->min_duration);430 pr_name_and_units(out, "max:", stats->max_duration);431 pr_name_and_units(out, "total:", stats->total_duration);432 433 prt_printf(out, "mean:\t");434 bch2_pr_time_units_aligned(out, d_mean);435 prt_tab(out);436 bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT));437 prt_newline(out);438 439 prt_printf(out, "stddev:\t");440 bch2_pr_time_units_aligned(out, d_stddev);441 prt_tab(out);442 bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->duration_stats_weighted, TIME_STATS_MV_WEIGHT));443 444 printbuf_indent_sub(out, 2);445 prt_newline(out);446 447 prt_printf(out, "time between events\n");448 printbuf_indent_add(out, 2);449 450 pr_name_and_units(out, "min:", stats->min_freq);451 pr_name_and_units(out, "max:", stats->max_freq);452 453 prt_printf(out, "mean:\t");454 bch2_pr_time_units_aligned(out, f_mean);455 prt_tab(out);456 bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->freq_stats_weighted, TIME_STATS_MV_WEIGHT));457 prt_newline(out);458 459 prt_printf(out, "stddev:\t");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 bch2_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 ", div64_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 do492 * some work493 * @d: the struct bch_ratelimit to update494 * Returns: the amount of time to delay by, in jiffies495 */496u64 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 done507 * @d: the struct bch_ratelimit to update508 * @done: the amount of work done, in arbitrary units509 */510void 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 value528 * @actual: current value529 *530 * @sign: 1 or -1; 1 if increasing the rate makes actual go up, -1 if increasing531 * it makes actual go down.532 */533void 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 577void 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 587void 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:\t");593 prt_human_readable_s64(out, pd->rate.rate);594 prt_newline(out);595 596 prt_printf(out, "target:\t");597 prt_human_readable_u64(out, pd->last_target);598 prt_newline(out);599 600 prt_printf(out, "actual:\t");601 prt_human_readable_u64(out, pd->last_actual);602 prt_newline(out);603 604 prt_printf(out, "proportional:\t");605 prt_human_readable_s64(out, pd->last_proportional);606 prt_newline(out);607 608 prt_printf(out, "derivative:\t");609 prt_human_readable_s64(out, pd->last_derivative);610 prt_newline(out);611 612 prt_printf(out, "change:\t");613 prt_human_readable_s64(out, pd->last_change);614 prt_newline(out);615 616 prt_printf(out, "next io:\t%llims\n", div64_s64(pd->rate.next - local_clock(), NSEC_PER_MSEC));617}618 619/* misc: */620 621void bch2_bio_map(struct bio *bio, void *base, size_t size)622{623 while (size) {624 struct page *page = is_vmalloc_addr(base)625 ? vmalloc_to_page(base)626 : virt_to_page(base);627 unsigned offset = offset_in_page(base);628 unsigned len = min_t(size_t, PAGE_SIZE - offset, size);629 630 BUG_ON(!bio_add_page(bio, page, len, offset));631 size -= len;632 base += len;633 }634}635 636int bch2_bio_alloc_pages(struct bio *bio, size_t size, gfp_t gfp_mask)637{638 while (size) {639 struct page *page = alloc_pages(gfp_mask, 0);640 unsigned len = min_t(size_t, PAGE_SIZE, size);641 642 if (!page)643 return -ENOMEM;644 645 if (unlikely(!bio_add_page(bio, page, len, 0))) {646 __free_page(page);647 break;648 }649 650 size -= len;651 }652 653 return 0;654}655 656size_t bch2_rand_range(size_t max)657{658 size_t rand;659 660 if (!max)661 return 0;662 663 do {664 rand = get_random_long();665 rand &= roundup_pow_of_two(max) - 1;666 } while (rand >= max);667 668 return rand;669}670 671void memcpy_to_bio(struct bio *dst, struct bvec_iter dst_iter, const void *src)672{673 struct bio_vec bv;674 struct bvec_iter iter;675 676 __bio_for_each_segment(bv, dst, iter, dst_iter) {677 void *dstp = kmap_local_page(bv.bv_page);678 679 memcpy(dstp + bv.bv_offset, src, bv.bv_len);680 kunmap_local(dstp);681 682 src += bv.bv_len;683 }684}685 686void memcpy_from_bio(void *dst, struct bio *src, struct bvec_iter src_iter)687{688 struct bio_vec bv;689 struct bvec_iter iter;690 691 __bio_for_each_segment(bv, src, iter, src_iter) {692 void *srcp = kmap_local_page(bv.bv_page);693 694 memcpy(dst, srcp + bv.bv_offset, bv.bv_len);695 kunmap_local(srcp);696 697 dst += bv.bv_len;698 }699}700 701#if 0702void eytzinger1_test(void)703{704 unsigned inorder, eytz, size;705 706 pr_info("1 based eytzinger test:");707 708 for (size = 2;709 size < 65536;710 size++) {711 unsigned extra = eytzinger1_extra(size);712 713 if (!(size % 4096))714 pr_info("tree size %u", size);715 716 BUG_ON(eytzinger1_prev(0, size) != eytzinger1_last(size));717 BUG_ON(eytzinger1_next(0, size) != eytzinger1_first(size));718 719 BUG_ON(eytzinger1_prev(eytzinger1_first(size), size) != 0);720 BUG_ON(eytzinger1_next(eytzinger1_last(size), size) != 0);721 722 inorder = 1;723 eytzinger1_for_each(eytz, size) {724 BUG_ON(__inorder_to_eytzinger1(inorder, size, extra) != eytz);725 BUG_ON(__eytzinger1_to_inorder(eytz, size, extra) != inorder);726 BUG_ON(eytz != eytzinger1_last(size) &&727 eytzinger1_prev(eytzinger1_next(eytz, size), size) != eytz);728 729 inorder++;730 }731 }732}733 734void eytzinger0_test(void)735{736 737 unsigned inorder, eytz, size;738 739 pr_info("0 based eytzinger test:");740 741 for (size = 1;742 size < 65536;743 size++) {744 unsigned extra = eytzinger0_extra(size);745 746 if (!(size % 4096))747 pr_info("tree size %u", size);748 749 BUG_ON(eytzinger0_prev(-1, size) != eytzinger0_last(size));750 BUG_ON(eytzinger0_next(-1, size) != eytzinger0_first(size));751 752 BUG_ON(eytzinger0_prev(eytzinger0_first(size), size) != -1);753 BUG_ON(eytzinger0_next(eytzinger0_last(size), size) != -1);754 755 inorder = 0;756 eytzinger0_for_each(eytz, size) {757 BUG_ON(__inorder_to_eytzinger0(inorder, size, extra) != eytz);758 BUG_ON(__eytzinger0_to_inorder(eytz, size, extra) != inorder);759 BUG_ON(eytz != eytzinger0_last(size) &&760 eytzinger0_prev(eytzinger0_next(eytz, size), size) != eytz);761 762 inorder++;763 }764 }765}766 767static inline int cmp_u16(const void *_l, const void *_r, size_t size)768{769 const u16 *l = _l, *r = _r;770 771 return (*l > *r) - (*r - *l);772}773 774static void eytzinger0_find_test_val(u16 *test_array, unsigned nr, u16 search)775{776 int i, c1 = -1, c2 = -1;777 ssize_t r;778 779 r = eytzinger0_find_le(test_array, nr,780 sizeof(test_array[0]),781 cmp_u16, &search);782 if (r >= 0)783 c1 = test_array[r];784 785 for (i = 0; i < nr; i++)786 if (test_array[i] <= search && test_array[i] > c2)787 c2 = test_array[i];788 789 if (c1 != c2) {790 eytzinger0_for_each(i, nr)791 pr_info("[%3u] = %12u", i, test_array[i]);792 pr_info("find_le(%2u) -> [%2zi] = %2i should be %2i",793 i, r, c1, c2);794 }795}796 797void eytzinger0_find_test(void)798{799 unsigned i, nr, allocated = 1 << 12;800 u16 *test_array = kmalloc_array(allocated, sizeof(test_array[0]), GFP_KERNEL);801 802 for (nr = 1; nr < allocated; nr++) {803 pr_info("testing %u elems", nr);804 805 get_random_bytes(test_array, nr * sizeof(test_array[0]));806 eytzinger0_sort(test_array, nr, sizeof(test_array[0]), cmp_u16, NULL);807 808 /* verify array is sorted correctly: */809 eytzinger0_for_each(i, nr)810 BUG_ON(i != eytzinger0_last(nr) &&811 test_array[i] > test_array[eytzinger0_next(i, nr)]);812 813 for (i = 0; i < U16_MAX; i += 1 << 12)814 eytzinger0_find_test_val(test_array, nr, i);815 816 for (i = 0; i < nr; i++) {817 eytzinger0_find_test_val(test_array, nr, test_array[i] - 1);818 eytzinger0_find_test_val(test_array, nr, test_array[i]);819 eytzinger0_find_test_val(test_array, nr, test_array[i] + 1);820 }821 }822 823 kfree(test_array);824}825#endif826 827/*828 * Accumulate percpu counters onto one cpu's copy - only valid when access829 * against any percpu counter is guarded against830 */831u64 *bch2_acc_percpu_u64s(u64 __percpu *p, unsigned nr)832{833 u64 *ret;834 int cpu;835 836 /* access to pcpu vars has to be blocked by other locking */837 preempt_disable();838 ret = this_cpu_ptr(p);839 preempt_enable();840 841 for_each_possible_cpu(cpu) {842 u64 *i = per_cpu_ptr(p, cpu);843 844 if (i != ret) {845 acc_u64s(ret, i, nr);846 memset(i, 0, nr * sizeof(u64));847 }848 }849 850 return ret;851}852 853void bch2_darray_str_exit(darray_str *d)854{855 darray_for_each(*d, i)856 kfree(*i);857 darray_exit(d);858}859 860int bch2_split_devs(const char *_dev_name, darray_str *ret)861{862 darray_init(ret);863 864 char *dev_name, *s, *orig;865 866 dev_name = orig = kstrdup(_dev_name, GFP_KERNEL);867 if (!dev_name)868 return -ENOMEM;869 870 while ((s = strsep(&dev_name, ":"))) {871 char *p = kstrdup(s, GFP_KERNEL);872 if (!p)873 goto err;874 875 if (darray_push(ret, p)) {876 kfree(p);877 goto err;878 }879 }880 881 kfree(orig);882 return 0;883err:884 bch2_darray_str_exit(ret);885 kfree(orig);886 return -ENOMEM;887}888