xref: /linux/fs/bcachefs/util.c (revision dbcedec3a31119d7594baacc743300d127c99c56)
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 
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_gfp(stack, stack->size * 2, gfp)));
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 = bch2_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 = 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 
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 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(&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(&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 			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 ", 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 static int alignment_ok(const void *base, size_t align)
711 {
712 	return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ||
713 		((unsigned long)base & (align - 1)) == 0;
714 }
715 
716 static void u32_swap(void *a, void *b, size_t size)
717 {
718 	u32 t = *(u32 *)a;
719 	*(u32 *)a = *(u32 *)b;
720 	*(u32 *)b = t;
721 }
722 
723 static void u64_swap(void *a, void *b, size_t size)
724 {
725 	u64 t = *(u64 *)a;
726 	*(u64 *)a = *(u64 *)b;
727 	*(u64 *)b = t;
728 }
729 
730 static void generic_swap(void *a, void *b, size_t size)
731 {
732 	char t;
733 
734 	do {
735 		t = *(char *)a;
736 		*(char *)a++ = *(char *)b;
737 		*(char *)b++ = t;
738 	} while (--size > 0);
739 }
740 
741 static inline int do_cmp(void *base, size_t n, size_t size,
742 			 int (*cmp_func)(const void *, const void *, size_t),
743 			 size_t l, size_t r)
744 {
745 	return cmp_func(base + inorder_to_eytzinger0(l, n) * size,
746 			base + inorder_to_eytzinger0(r, n) * size,
747 			size);
748 }
749 
750 static inline void do_swap(void *base, size_t n, size_t size,
751 			   void (*swap_func)(void *, void *, size_t),
752 			   size_t l, size_t r)
753 {
754 	swap_func(base + inorder_to_eytzinger0(l, n) * size,
755 		  base + inorder_to_eytzinger0(r, n) * size,
756 		  size);
757 }
758 
759 void eytzinger0_sort(void *base, size_t n, size_t size,
760 		     int (*cmp_func)(const void *, const void *, size_t),
761 		     void (*swap_func)(void *, void *, size_t))
762 {
763 	int i, c, r;
764 
765 	if (!swap_func) {
766 		if (size == 4 && alignment_ok(base, 4))
767 			swap_func = u32_swap;
768 		else if (size == 8 && alignment_ok(base, 8))
769 			swap_func = u64_swap;
770 		else
771 			swap_func = generic_swap;
772 	}
773 
774 	/* heapify */
775 	for (i = n / 2 - 1; i >= 0; --i) {
776 		for (r = i; r * 2 + 1 < n; r = c) {
777 			c = r * 2 + 1;
778 
779 			if (c + 1 < n &&
780 			    do_cmp(base, n, size, cmp_func, c, c + 1) < 0)
781 				c++;
782 
783 			if (do_cmp(base, n, size, cmp_func, r, c) >= 0)
784 				break;
785 
786 			do_swap(base, n, size, swap_func, r, c);
787 		}
788 	}
789 
790 	/* sort */
791 	for (i = n - 1; i > 0; --i) {
792 		do_swap(base, n, size, swap_func, 0, i);
793 
794 		for (r = 0; r * 2 + 1 < i; r = c) {
795 			c = r * 2 + 1;
796 
797 			if (c + 1 < i &&
798 			    do_cmp(base, n, size, cmp_func, c, c + 1) < 0)
799 				c++;
800 
801 			if (do_cmp(base, n, size, cmp_func, r, c) >= 0)
802 				break;
803 
804 			do_swap(base, n, size, swap_func, r, c);
805 		}
806 	}
807 }
808 
809 void sort_cmp_size(void *base, size_t num, size_t size,
810 	  int (*cmp_func)(const void *, const void *, size_t),
811 	  void (*swap_func)(void *, void *, size_t size))
812 {
813 	/* pre-scale counters for performance */
814 	int i = (num/2 - 1) * size, n = num * size, c, r;
815 
816 	if (!swap_func) {
817 		if (size == 4 && alignment_ok(base, 4))
818 			swap_func = u32_swap;
819 		else if (size == 8 && alignment_ok(base, 8))
820 			swap_func = u64_swap;
821 		else
822 			swap_func = generic_swap;
823 	}
824 
825 	/* heapify */
826 	for ( ; i >= 0; i -= size) {
827 		for (r = i; r * 2 + size < n; r  = c) {
828 			c = r * 2 + size;
829 			if (c < n - size &&
830 			    cmp_func(base + c, base + c + size, size) < 0)
831 				c += size;
832 			if (cmp_func(base + r, base + c, size) >= 0)
833 				break;
834 			swap_func(base + r, base + c, size);
835 		}
836 	}
837 
838 	/* sort */
839 	for (i = n - size; i > 0; i -= size) {
840 		swap_func(base, base + i, size);
841 		for (r = 0; r * 2 + size < i; r = c) {
842 			c = r * 2 + size;
843 			if (c < i - size &&
844 			    cmp_func(base + c, base + c + size, size) < 0)
845 				c += size;
846 			if (cmp_func(base + r, base + c, size) >= 0)
847 				break;
848 			swap_func(base + r, base + c, size);
849 		}
850 	}
851 }
852 
853 #if 0
854 void eytzinger1_test(void)
855 {
856 	unsigned inorder, eytz, size;
857 
858 	pr_info("1 based eytzinger test:");
859 
860 	for (size = 2;
861 	     size < 65536;
862 	     size++) {
863 		unsigned extra = eytzinger1_extra(size);
864 
865 		if (!(size % 4096))
866 			pr_info("tree size %u", size);
867 
868 		BUG_ON(eytzinger1_prev(0, size) != eytzinger1_last(size));
869 		BUG_ON(eytzinger1_next(0, size) != eytzinger1_first(size));
870 
871 		BUG_ON(eytzinger1_prev(eytzinger1_first(size), size)	!= 0);
872 		BUG_ON(eytzinger1_next(eytzinger1_last(size), size)	!= 0);
873 
874 		inorder = 1;
875 		eytzinger1_for_each(eytz, size) {
876 			BUG_ON(__inorder_to_eytzinger1(inorder, size, extra) != eytz);
877 			BUG_ON(__eytzinger1_to_inorder(eytz, size, extra) != inorder);
878 			BUG_ON(eytz != eytzinger1_last(size) &&
879 			       eytzinger1_prev(eytzinger1_next(eytz, size), size) != eytz);
880 
881 			inorder++;
882 		}
883 	}
884 }
885 
886 void eytzinger0_test(void)
887 {
888 
889 	unsigned inorder, eytz, size;
890 
891 	pr_info("0 based eytzinger test:");
892 
893 	for (size = 1;
894 	     size < 65536;
895 	     size++) {
896 		unsigned extra = eytzinger0_extra(size);
897 
898 		if (!(size % 4096))
899 			pr_info("tree size %u", size);
900 
901 		BUG_ON(eytzinger0_prev(-1, size) != eytzinger0_last(size));
902 		BUG_ON(eytzinger0_next(-1, size) != eytzinger0_first(size));
903 
904 		BUG_ON(eytzinger0_prev(eytzinger0_first(size), size)	!= -1);
905 		BUG_ON(eytzinger0_next(eytzinger0_last(size), size)	!= -1);
906 
907 		inorder = 0;
908 		eytzinger0_for_each(eytz, size) {
909 			BUG_ON(__inorder_to_eytzinger0(inorder, size, extra) != eytz);
910 			BUG_ON(__eytzinger0_to_inorder(eytz, size, extra) != inorder);
911 			BUG_ON(eytz != eytzinger0_last(size) &&
912 			       eytzinger0_prev(eytzinger0_next(eytz, size), size) != eytz);
913 
914 			inorder++;
915 		}
916 	}
917 }
918 
919 static inline int cmp_u16(const void *_l, const void *_r, size_t size)
920 {
921 	const u16 *l = _l, *r = _r;
922 
923 	return (*l > *r) - (*r - *l);
924 }
925 
926 static void eytzinger0_find_test_val(u16 *test_array, unsigned nr, u16 search)
927 {
928 	int i, c1 = -1, c2 = -1;
929 	ssize_t r;
930 
931 	r = eytzinger0_find_le(test_array, nr,
932 			       sizeof(test_array[0]),
933 			       cmp_u16, &search);
934 	if (r >= 0)
935 		c1 = test_array[r];
936 
937 	for (i = 0; i < nr; i++)
938 		if (test_array[i] <= search && test_array[i] > c2)
939 			c2 = test_array[i];
940 
941 	if (c1 != c2) {
942 		eytzinger0_for_each(i, nr)
943 			pr_info("[%3u] = %12u", i, test_array[i]);
944 		pr_info("find_le(%2u) -> [%2zi] = %2i should be %2i",
945 			i, r, c1, c2);
946 	}
947 }
948 
949 void eytzinger0_find_test(void)
950 {
951 	unsigned i, nr, allocated = 1 << 12;
952 	u16 *test_array = kmalloc_array(allocated, sizeof(test_array[0]), GFP_KERNEL);
953 
954 	for (nr = 1; nr < allocated; nr++) {
955 		pr_info("testing %u elems", nr);
956 
957 		get_random_bytes(test_array, nr * sizeof(test_array[0]));
958 		eytzinger0_sort(test_array, nr, sizeof(test_array[0]), cmp_u16, NULL);
959 
960 		/* verify array is sorted correctly: */
961 		eytzinger0_for_each(i, nr)
962 			BUG_ON(i != eytzinger0_last(nr) &&
963 			       test_array[i] > test_array[eytzinger0_next(i, nr)]);
964 
965 		for (i = 0; i < U16_MAX; i += 1 << 12)
966 			eytzinger0_find_test_val(test_array, nr, i);
967 
968 		for (i = 0; i < nr; i++) {
969 			eytzinger0_find_test_val(test_array, nr, test_array[i] - 1);
970 			eytzinger0_find_test_val(test_array, nr, test_array[i]);
971 			eytzinger0_find_test_val(test_array, nr, test_array[i] + 1);
972 		}
973 	}
974 
975 	kfree(test_array);
976 }
977 #endif
978 
979 /*
980  * Accumulate percpu counters onto one cpu's copy - only valid when access
981  * against any percpu counter is guarded against
982  */
983 u64 *bch2_acc_percpu_u64s(u64 __percpu *p, unsigned nr)
984 {
985 	u64 *ret;
986 	int cpu;
987 
988 	/* access to pcpu vars has to be blocked by other locking */
989 	preempt_disable();
990 	ret = this_cpu_ptr(p);
991 	preempt_enable();
992 
993 	for_each_possible_cpu(cpu) {
994 		u64 *i = per_cpu_ptr(p, cpu);
995 
996 		if (i != ret) {
997 			acc_u64s(ret, i, nr);
998 			memset(i, 0, nr * sizeof(u64));
999 		}
1000 	}
1001 
1002 	return ret;
1003 }
1004 
1005 void bch2_darray_str_exit(darray_str *d)
1006 {
1007 	darray_for_each(*d, i)
1008 		kfree(*i);
1009 	darray_exit(d);
1010 }
1011 
1012 int bch2_split_devs(const char *_dev_name, darray_str *ret)
1013 {
1014 	darray_init(ret);
1015 
1016 	char *dev_name, *s, *orig;
1017 
1018 	dev_name = orig = kstrdup(_dev_name, GFP_KERNEL);
1019 	if (!dev_name)
1020 		return -ENOMEM;
1021 
1022 	while ((s = strsep(&dev_name, ":"))) {
1023 		char *p = kstrdup(s, GFP_KERNEL);
1024 		if (!p)
1025 			goto err;
1026 
1027 		if (darray_push(ret, p)) {
1028 			kfree(p);
1029 			goto err;
1030 		}
1031 	}
1032 
1033 	kfree(orig);
1034 	return 0;
1035 err:
1036 	bch2_darray_str_exit(ret);
1037 	kfree(orig);
1038 	return -ENOMEM;
1039 }
1040