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/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(c: *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(c: *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 > div_u64(U64_MAX, divisor: 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(n: base, p: 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, res: &f_n);
132 if (ret < 0)
133 return ret;
134 cp += ret;
135
136 ret = bch2_pow(n: 10, p: ret, res: &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, divisor: b))
144 return -ERANGE;
145 v *= b;
146
147 if (f_n > div_u64(U64_MAX, divisor: b))
148 return -ERANGE;
149
150 f_n = div_u64(dividend: f_n * b, divisor: 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(char *opt, const char * const list[])
208{
209 u64 ret = 0;
210 char *p, *s, *d = kstrdup(s: 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(array: list, n: -1, string: p);
219
220 if (flag < 0) {
221 ret = -1;
222 break;
223 }
224
225 ret |= 1 << flag;
226 }
227
228 kfree(objp: 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, c: '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, nr_bits: fls64(x: v) ?: 1);
253}
254
255void 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
275int 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(sem: &task->signal->exec_update_lock))
287 return -1;
288
289 do {
290 nr_entries = stack_trace_save_tsk(task, store: stack->data, size: stack->size, skipnr: skipnr + 1);
291 } while (nr_entries == stack->size &&
292 !(ret = darray_make_room_gfp(stack, stack->size * 2, gfp)));
293
294 stack->nr = nr_entries;
295 up_read(sem: &task->signal->exec_update_lock);
296
297 return ret;
298#else
299 return 0;
300#endif
301}
302
303void 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
311int 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: &stack, task, skipnr: skipnr + 1, gfp);
315
316 bch2_prt_backtrace(out, stack: &stack);
317 darray_exit(&stack);
318 return ret;
319}
320
321#ifndef __KERNEL__
322#include <time.h>
323void 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
332void bch2_prt_datetime(struct printbuf *out, time64_t sec)
333{
334 char buf[64];
335 snprintf(buf, size: sizeof(buf), fmt: "%ptT", &sec);
336 prt_u64(out, sec);
337}
338#endif
339
340void bch2_pr_time_units(struct printbuf *out, u64 ns)
341{
342 const struct time_unit *u = bch2_pick_time_units(ns);
343
344 prt_printf(out, "%llu %s", div_u64(ns, u->nsecs), u->name);
345}
346
347static void bch2_pr_time_units_aligned(struct printbuf *out, u64 ns)
348{
349 const struct time_unit *u = bch2_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
356static inline void pr_name_and_units(struct printbuf *out, const char *name, u64 ns)
357{
358 prt_str(out, str: 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
366void bch2_time_stats_to_text(struct printbuf *out, struct bch2_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(lock: &stats->lock);
376 for_each_possible_cpu(cpu)
377 __bch2_time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu));
378 spin_unlock_irq(lock: &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(s: stats->freq_stats);
386 f_stddev = mean_and_variance_get_stddev(s: stats->freq_stats);
387 d_mean = mean_and_variance_get_mean(s: stats->duration_stats);
388 d_stddev = mean_and_variance_get_stddev(s: 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, name: "min:", ns: stats->min_duration);
425 pr_name_and_units(out, name: "max:", ns: stats->max_duration);
426 pr_name_and_units(out, name: "total:", ns: stats->total_duration);
427
428 prt_printf(out, "mean:");
429 prt_tab(out);
430 bch2_pr_time_units_aligned(out, ns: d_mean);
431 prt_tab(out);
432 bch2_pr_time_units_aligned(out, ns: mean_and_variance_weighted_get_mean(s: 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, ns: d_stddev);
438 prt_tab(out);
439 bch2_pr_time_units_aligned(out, ns: mean_and_variance_weighted_get_stddev(s: 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, name: "min:", ns: stats->min_freq);
449 pr_name_and_units(out, name: "max:", ns: stats->max_freq);
450
451 prt_printf(out, "mean:");
452 prt_tab(out);
453 bch2_pr_time_units_aligned(out, ns: f_mean);
454 prt_tab(out);
455 bch2_pr_time_units_aligned(out, ns: mean_and_variance_weighted_get_mean(s: 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, ns: f_stddev);
461 prt_tab(out);
462 bch2_pr_time_units_aligned(out, ns: mean_and_variance_weighted_get_stddev(s: 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(ns: 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 */
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(n: 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 */
510void bch2_ratelimit_increment(struct bch_ratelimit *d, u64 done)
511{
512 u64 now = local_clock();
513
514 d->next += div_u64(dividend: done * NSEC_PER_SEC, divisor: 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 */
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(dividend: proportional, divisor: pd->p_term_inverse);
548
549 derivative = actual - pd->last_actual;
550 derivative = div_s64(dividend: derivative, divisor: 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(dividend: derivative, divisor: 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:");
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
630void bch2_bio_map(struct bio *bio, void *base, size_t size)
631{
632 while (size) {
633 struct page *page = is_vmalloc_addr(x: base)
634 ? vmalloc_to_page(addr: 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
645int 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: gfp_mask, order: 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
665size_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
680void 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(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
695void 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(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
711void 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
743void 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
776static 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
783static 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
806void 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 */
840u64 *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(acc: ret, src: i, nr);
855 memset(i, 0, nr * sizeof(u64));
856 }
857 }
858
859 return ret;
860}
861
862void bch2_darray_str_exit(darray_str *d)
863{
864 darray_for_each(*d, i)
865 kfree(objp: *i);
866 darray_exit(d);
867}
868
869int 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(s: _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(objp: p);
886 goto err;
887 }
888 }
889
890 kfree(objp: orig);
891 return 0;
892err:
893 bch2_darray_str_exit(d: ret);
894 kfree(objp: orig);
895 return -ENOMEM;
896}
897

source code of linux/fs/bcachefs/util.c