Adding upstream version 6.7.7.upstream/6.7.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1160 insertions, 0 deletions

diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
new file mode 100644
index 0000000000..3b7c349f26
--- /dev/null
+++ b/fs/bcachefs/util.c
@@ -0,0 +1,1160 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * random utiility code, for bcache but in theory not specific to bcache
+ *
+ * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
+ * Copyright 2012 Google, Inc.
+ */
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/console.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/log2.h>
+#include <linux/math64.h>
+#include <linux/percpu.h>
+#include <linux/preempt.h>
+#include <linux/random.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/sched/clock.h>
+
+#include "eytzinger.h"
+#include "mean_and_variance.h"
+#include "util.h"
+
+static const char si_units[] = "?kMGTPEZY";
+
+/* string_get_size units: */
+static const char *const units_2[] = {
+	"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"
+};
+static const char *const units_10[] = {
+	"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"
+};
+
+static int parse_u64(const char *cp, u64 *res)
+{
+	const char *start = cp;
+	u64 v = 0;
+
+	if (!isdigit(*cp))
+		return -EINVAL;
+
+	do {
+		if (v > U64_MAX / 10)
+			return -ERANGE;
+		v *= 10;
+		if (v > U64_MAX - (*cp - '0'))
+			return -ERANGE;
+		v += *cp - '0';
+		cp++;
+	} while (isdigit(*cp));
+
+	*res = v;
+	return cp - start;
+}
+
+static int bch2_pow(u64 n, u64 p, u64 *res)
+{
+	*res = 1;
+
+	while (p--) {
+		if (*res > div_u64(U64_MAX, n))
+			return -ERANGE;
+		*res *= n;
+	}
+	return 0;
+}
+
+static int parse_unit_suffix(const char *cp, u64 *res)
+{
+	const char *start = cp;
+	u64 base = 1024;
+	unsigned u;
+	int ret;
+
+	if (*cp == ' ')
+		cp++;
+
+	for (u = 1; u < strlen(si_units); u++)
+		if (*cp == si_units[u]) {
+			cp++;
+			goto got_unit;
+		}
+
+	for (u = 0; u < ARRAY_SIZE(units_2); u++)
+		if (!strncmp(cp, units_2[u], strlen(units_2[u]))) {
+			cp += strlen(units_2[u]);
+			goto got_unit;
+		}
+
+	for (u = 0; u < ARRAY_SIZE(units_10); u++)
+		if (!strncmp(cp, units_10[u], strlen(units_10[u]))) {
+			cp += strlen(units_10[u]);
+			base = 1000;
+			goto got_unit;
+		}
+
+	*res = 1;
+	return 0;
+got_unit:
+	ret = bch2_pow(base, u, res);
+	if (ret)
+		return ret;
+
+	return cp - start;
+}
+
+#define parse_or_ret(cp, _f)			\
+do {						\
+	int _ret = _f;				\
+	if (_ret < 0)				\
+		return _ret;			\
+	cp += _ret;				\
+} while (0)
+
+static int __bch2_strtou64_h(const char *cp, u64 *res)
+{
+	const char *start = cp;
+	u64 v = 0, b, f_n = 0, f_d = 1;
+	int ret;
+
+	parse_or_ret(cp, parse_u64(cp, &v));
+
+	if (*cp == '.') {
+		cp++;
+		ret = parse_u64(cp, &f_n);
+		if (ret < 0)
+			return ret;
+		cp += ret;
+
+		ret = bch2_pow(10, ret, &f_d);
+		if (ret)
+			return ret;
+	}
+
+	parse_or_ret(cp, parse_unit_suffix(cp, &b));
+
+	if (v > div_u64(U64_MAX, b))
+		return -ERANGE;
+	v *= b;
+
+	if (f_n > div_u64(U64_MAX, b))
+		return -ERANGE;
+
+	f_n = div_u64(f_n * b, f_d);
+	if (v + f_n < v)
+		return -ERANGE;
+	v += f_n;
+
+	*res = v;
+	return cp - start;
+}
+
+static int __bch2_strtoh(const char *cp, u64 *res,
+			 u64 t_max, bool t_signed)
+{
+	bool positive = *cp != '-';
+	u64 v = 0;
+
+	if (*cp == '+' || *cp == '-')
+		cp++;
+
+	parse_or_ret(cp, __bch2_strtou64_h(cp, &v));
+
+	if (*cp == '\n')
+		cp++;
+	if (*cp)
+		return -EINVAL;
+
+	if (positive) {
+		if (v > t_max)
+			return -ERANGE;
+	} else {
+		if (v && !t_signed)
+			return -ERANGE;
+
+		if (v > t_max + 1)
+			return -ERANGE;
+		v = -v;
+	}
+
+	*res = v;
+	return 0;
+}
+
+#define STRTO_H(name, type)					\
+int bch2_ ## name ## _h(const char *cp, type *res)		\
+{								\
+	u64 v = 0;						\
+	int ret = __bch2_strtoh(cp, &v, ANYSINT_MAX(type),	\
+			ANYSINT_MAX(type) != ((type) ~0ULL));	\
+	*res = v;						\
+	return ret;						\
+}
+
+STRTO_H(strtoint, int)
+STRTO_H(strtouint, unsigned int)
+STRTO_H(strtoll, long long)
+STRTO_H(strtoull, unsigned long long)
+STRTO_H(strtou64, u64)
+
+u64 bch2_read_flag_list(char *opt, const char * const list[])
+{
+	u64 ret = 0;
+	char *p, *s, *d = kstrdup(opt, GFP_KERNEL);
+
+	if (!d)
+		return -ENOMEM;
+
+	s = strim(d);
+
+	while ((p = strsep(&s, ","))) {
+		int flag = match_string(list, -1, p);
+
+		if (flag < 0) {
+			ret = -1;
+			break;
+		}
+
+		ret |= 1 << flag;
+	}
+
+	kfree(d);
+
+	return ret;
+}
+
+bool bch2_is_zero(const void *_p, size_t n)
+{
+	const char *p = _p;
+	size_t i;
+
+	for (i = 0; i < n; i++)
+		if (p[i])
+			return false;
+	return true;
+}
+
+void bch2_prt_u64_binary(struct printbuf *out, u64 v, unsigned nr_bits)
+{
+	while (nr_bits)
+		prt_char(out, '0' + ((v >> --nr_bits) & 1));
+}
+
+void bch2_print_string_as_lines(const char *prefix, const char *lines)
+{
+	const char *p;
+
+	if (!lines) {
+		printk("%s (null)\n", prefix);
+		return;
+	}
+
+	console_lock();
+	while (1) {
+		p = strchrnul(lines, '\n');
+		printk("%s%.*s\n", prefix, (int) (p - lines), lines);
+		if (!*p)
+			break;
+		lines = p + 1;
+	}
+	console_unlock();
+}
+
+int bch2_save_backtrace(bch_stacktrace *stack, struct task_struct *task)
+{
+#ifdef CONFIG_STACKTRACE
+	unsigned nr_entries = 0;
+	int ret = 0;
+
+	stack->nr = 0;
+	ret = darray_make_room(stack, 32);
+	if (ret)
+		return ret;
+
+	if (!down_read_trylock(&task->signal->exec_update_lock))
+		return -1;
+
+	do {
+		nr_entries = stack_trace_save_tsk(task, stack->data, stack->size, 0);
+	} while (nr_entries == stack->size &&
+		 !(ret = darray_make_room(stack, stack->size * 2)));
+
+	stack->nr = nr_entries;
+	up_read(&task->signal->exec_update_lock);
+
+	return ret;
+#else
+	return 0;
+#endif
+}
+
+void bch2_prt_backtrace(struct printbuf *out, bch_stacktrace *stack)
+{
+	unsigned long *i;
+
+	darray_for_each(*stack, i) {
+		prt_printf(out, "[<0>] %pB", (void *) *i);
+		prt_newline(out);
+	}
+}
+
+int bch2_prt_task_backtrace(struct printbuf *out, struct task_struct *task)
+{
+	bch_stacktrace stack = { 0 };
+	int ret = bch2_save_backtrace(&stack, task);
+
+	bch2_prt_backtrace(out, &stack);
+	darray_exit(&stack);
+	return ret;
+}
+
+/* time stats: */
+
+#ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
+static void bch2_quantiles_update(struct bch2_quantiles *q, u64 v)
+{
+	unsigned i = 0;
+
+	while (i < ARRAY_SIZE(q->entries)) {
+		struct bch2_quantile_entry *e = q->entries + i;
+
+		if (unlikely(!e->step)) {
+			e->m = v;
+			e->step = max_t(unsigned, v / 2, 1024);
+		} else if (e->m > v) {
+			e->m = e->m >= e->step
+				? e->m - e->step
+				: 0;
+		} else if (e->m < v) {
+			e->m = e->m + e->step > e->m
+				? e->m + e->step
+				: U32_MAX;
+		}
+
+		if ((e->m > v ? e->m - v : v - e->m) < e->step)
+			e->step = max_t(unsigned, e->step / 2, 1);
+
+		if (v >= e->m)
+			break;
+
+		i = eytzinger0_child(i, v > e->m);
+	}
+}
+
+static inline void bch2_time_stats_update_one(struct bch2_time_stats *stats,
+					      u64 start, u64 end)
+{
+	u64 duration, freq;
+
+	if (time_after64(end, start)) {
+		duration = end - start;
+		mean_and_variance_update(&stats->duration_stats, duration);
+		mean_and_variance_weighted_update(&stats->duration_stats_weighted, duration);
+		stats->max_duration = max(stats->max_duration, duration);
+		stats->min_duration = min(stats->min_duration, duration);
+		bch2_quantiles_update(&stats->quantiles, duration);
+	}
+
+	if (stats->last_event && time_after64(end, stats->last_event)) {
+		freq = end - stats->last_event;
+		mean_and_variance_update(&stats->freq_stats, freq);
+		mean_and_variance_weighted_update(&stats->freq_stats_weighted, freq);
+		stats->max_freq = max(stats->max_freq, freq);
+		stats->min_freq = min(stats->min_freq, freq);
+	}
+
+	stats->last_event = end;
+}
+
+static noinline void bch2_time_stats_clear_buffer(struct bch2_time_stats *stats,
+						  struct bch2_time_stat_buffer *b)
+{
+	struct bch2_time_stat_buffer_entry *i;
+	unsigned long flags;
+
+	spin_lock_irqsave(&stats->lock, flags);
+	for (i = b->entries;
+	     i < b->entries + ARRAY_SIZE(b->entries);
+	     i++)
+		bch2_time_stats_update_one(stats, i->start, i->end);
+	spin_unlock_irqrestore(&stats->lock, flags);
+
+	b->nr = 0;
+}
+
+void __bch2_time_stats_update(struct bch2_time_stats *stats, u64 start, u64 end)
+{
+	unsigned long flags;
+
+	WARN_RATELIMIT(!stats->min_duration || !stats->min_freq,
+		       "time_stats: min_duration = %llu, min_freq = %llu",
+		       stats->min_duration, stats->min_freq);
+
+	if (!stats->buffer) {
+		spin_lock_irqsave(&stats->lock, flags);
+		bch2_time_stats_update_one(stats, start, end);
+
+		if (mean_and_variance_weighted_get_mean(stats->freq_stats_weighted) < 32 &&
+		    stats->duration_stats.n > 1024)
+			stats->buffer =
+				alloc_percpu_gfp(struct bch2_time_stat_buffer,
+						 GFP_ATOMIC);
+		spin_unlock_irqrestore(&stats->lock, flags);
+	} else {
+		struct bch2_time_stat_buffer *b;
+
+		preempt_disable();
+		b = this_cpu_ptr(stats->buffer);
+
+		BUG_ON(b->nr >= ARRAY_SIZE(b->entries));
+		b->entries[b->nr++] = (struct bch2_time_stat_buffer_entry) {
+			.start = start,
+			.end = end
+		};
+
+		if (unlikely(b->nr == ARRAY_SIZE(b->entries)))
+			bch2_time_stats_clear_buffer(stats, b);
+		preempt_enable();
+	}
+}
+#endif
+
+static const struct time_unit {
+	const char	*name;
+	u64		nsecs;
+} time_units[] = {
+	{ "ns",		1		 },
+	{ "us",		NSEC_PER_USEC	 },
+	{ "ms",		NSEC_PER_MSEC	 },
+	{ "s",		NSEC_PER_SEC	 },
+	{ "m",          (u64) NSEC_PER_SEC * 60},
+	{ "h",          (u64) NSEC_PER_SEC * 3600},
+	{ "eon",        U64_MAX          },
+};
+
+static const struct time_unit *pick_time_units(u64 ns)
+{
+	const struct time_unit *u;
+
+	for (u = time_units;
+	     u + 1 < time_units + ARRAY_SIZE(time_units) &&
+	     ns >= u[1].nsecs << 1;
+	     u++)
+		;
+
+	return u;
+}
+
+void bch2_pr_time_units(struct printbuf *out, u64 ns)
+{
+	const struct time_unit *u = pick_time_units(ns);
+
+	prt_printf(out, "%llu %s", div_u64(ns, u->nsecs), u->name);
+}
+
+static void bch2_pr_time_units_aligned(struct printbuf *out, u64 ns)
+{
+	const struct time_unit *u = pick_time_units(ns);
+
+	prt_printf(out, "%llu ", div64_u64(ns, u->nsecs));
+	prt_tab_rjust(out);
+	prt_printf(out, "%s", u->name);
+}
+
+#ifndef __KERNEL__
+#include <time.h>
+void bch2_prt_datetime(struct printbuf *out, time64_t sec)
+{
+	time_t t = sec;
+	char buf[64];
+	ctime_r(&t, buf);
+	prt_str(out, buf);
+}
+#else
+void bch2_prt_datetime(struct printbuf *out, time64_t sec)
+{
+	char buf[64];
+	snprintf(buf, sizeof(buf), "%ptT", &sec);
+	prt_u64(out, sec);
+}
+#endif
+
+#define TABSTOP_SIZE 12
+
+static inline void pr_name_and_units(struct printbuf *out, const char *name, u64 ns)
+{
+	prt_str(out, name);
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, ns);
+	prt_newline(out);
+}
+
+void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats)
+{
+	const struct time_unit *u;
+	s64 f_mean = 0, d_mean = 0;
+	u64 q, last_q = 0, f_stddev = 0, d_stddev = 0;
+	int i;
+	/*
+	 * avoid divide by zero
+	 */
+	if (stats->freq_stats.n) {
+		f_mean = mean_and_variance_get_mean(stats->freq_stats);
+		f_stddev = mean_and_variance_get_stddev(stats->freq_stats);
+		d_mean = mean_and_variance_get_mean(stats->duration_stats);
+		d_stddev = mean_and_variance_get_stddev(stats->duration_stats);
+	}
+
+	printbuf_tabstop_push(out, out->indent + TABSTOP_SIZE);
+	prt_printf(out, "count:");
+	prt_tab(out);
+	prt_printf(out, "%llu ",
+			 stats->duration_stats.n);
+	printbuf_tabstop_pop(out);
+	prt_newline(out);
+
+	printbuf_tabstops_reset(out);
+
+	printbuf_tabstop_push(out, out->indent + 20);
+	printbuf_tabstop_push(out, TABSTOP_SIZE + 2);
+	printbuf_tabstop_push(out, 0);
+	printbuf_tabstop_push(out, TABSTOP_SIZE + 2);
+
+	prt_tab(out);
+	prt_printf(out, "since mount");
+	prt_tab_rjust(out);
+	prt_tab(out);
+	prt_printf(out, "recent");
+	prt_tab_rjust(out);
+	prt_newline(out);
+
+	printbuf_tabstops_reset(out);
+	printbuf_tabstop_push(out, out->indent + 20);
+	printbuf_tabstop_push(out, TABSTOP_SIZE);
+	printbuf_tabstop_push(out, 2);
+	printbuf_tabstop_push(out, TABSTOP_SIZE);
+
+	prt_printf(out, "duration of events");
+	prt_newline(out);
+	printbuf_indent_add(out, 2);
+
+	pr_name_and_units(out, "min:", stats->min_duration);
+	pr_name_and_units(out, "max:", stats->max_duration);
+
+	prt_printf(out, "mean:");
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, d_mean);
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->duration_stats_weighted));
+	prt_newline(out);
+
+	prt_printf(out, "stddev:");
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, d_stddev);
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->duration_stats_weighted));
+
+	printbuf_indent_sub(out, 2);
+	prt_newline(out);
+
+	prt_printf(out, "time between events");
+	prt_newline(out);
+	printbuf_indent_add(out, 2);
+
+	pr_name_and_units(out, "min:", stats->min_freq);
+	pr_name_and_units(out, "max:", stats->max_freq);
+
+	prt_printf(out, "mean:");
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, f_mean);
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_mean(stats->freq_stats_weighted));
+	prt_newline(out);
+
+	prt_printf(out, "stddev:");
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, f_stddev);
+	prt_tab(out);
+	bch2_pr_time_units_aligned(out, mean_and_variance_weighted_get_stddev(stats->freq_stats_weighted));
+
+	printbuf_indent_sub(out, 2);
+	prt_newline(out);
+
+	printbuf_tabstops_reset(out);
+
+	i = eytzinger0_first(NR_QUANTILES);
+	u = pick_time_units(stats->quantiles.entries[i].m);
+
+	prt_printf(out, "quantiles (%s):\t", u->name);
+	eytzinger0_for_each(i, NR_QUANTILES) {
+		bool is_last = eytzinger0_next(i, NR_QUANTILES) == -1;
+
+		q = max(stats->quantiles.entries[i].m, last_q);
+		prt_printf(out, "%llu ",
+		       div_u64(q, u->nsecs));
+		if (is_last)
+			prt_newline(out);
+		last_q = q;
+	}
+}
+
+void bch2_time_stats_exit(struct bch2_time_stats *stats)
+{
+	free_percpu(stats->buffer);
+}
+
+void bch2_time_stats_init(struct bch2_time_stats *stats)
+{
+	memset(stats, 0, sizeof(*stats));
+	stats->duration_stats_weighted.weight = 8;
+	stats->freq_stats_weighted.weight = 8;
+	stats->min_duration = U64_MAX;
+	stats->min_freq = U64_MAX;
+	spin_lock_init(&stats->lock);
+}
+
+/* ratelimit: */
+
+/**
+ * bch2_ratelimit_delay() - return how long to delay until the next time to do
+ *		some work
+ * @d:		the struct bch_ratelimit to update
+ * Returns:	the amount of time to delay by, in jiffies
+ */
+u64 bch2_ratelimit_delay(struct bch_ratelimit *d)
+{
+	u64 now = local_clock();
+
+	return time_after64(d->next, now)
+		? nsecs_to_jiffies(d->next - now)
+		: 0;
+}
+
+/**
+ * bch2_ratelimit_increment() - increment @d by the amount of work done
+ * @d:		the struct bch_ratelimit to update
+ * @done:	the amount of work done, in arbitrary units
+ */
+void bch2_ratelimit_increment(struct bch_ratelimit *d, u64 done)
+{
+	u64 now = local_clock();
+
+	d->next += div_u64(done * NSEC_PER_SEC, d->rate);
+
+	if (time_before64(now + NSEC_PER_SEC, d->next))
+		d->next = now + NSEC_PER_SEC;
+
+	if (time_after64(now - NSEC_PER_SEC * 2, d->next))
+		d->next = now - NSEC_PER_SEC * 2;
+}
+
+/* pd controller: */
+
+/*
+ * Updates pd_controller. Attempts to scale inputed values to units per second.
+ * @target: desired value
+ * @actual: current value
+ *
+ * @sign: 1 or -1; 1 if increasing the rate makes actual go up, -1 if increasing
+ * it makes actual go down.
+ */
+void bch2_pd_controller_update(struct bch_pd_controller *pd,
+			      s64 target, s64 actual, int sign)
+{
+	s64 proportional, derivative, change;
+
+	unsigned long seconds_since_update = (jiffies - pd->last_update) / HZ;
+
+	if (seconds_since_update == 0)
+		return;
+
+	pd->last_update = jiffies;
+
+	proportional = actual - target;
+	proportional *= seconds_since_update;
+	proportional = div_s64(proportional, pd->p_term_inverse);
+
+	derivative = actual - pd->last_actual;
+	derivative = div_s64(derivative, seconds_since_update);
+	derivative = ewma_add(pd->smoothed_derivative, derivative,
+			      (pd->d_term / seconds_since_update) ?: 1);
+	derivative = derivative * pd->d_term;
+	derivative = div_s64(derivative, pd->p_term_inverse);
+
+	change = proportional + derivative;
+
+	/* Don't increase rate if not keeping up */
+	if (change > 0 &&
+	    pd->backpressure &&
+	    time_after64(local_clock(),
+			 pd->rate.next + NSEC_PER_MSEC))
+		change = 0;
+
+	change *= (sign * -1);
+
+	pd->rate.rate = clamp_t(s64, (s64) pd->rate.rate + change,
+				1, UINT_MAX);
+
+	pd->last_actual		= actual;
+	pd->last_derivative	= derivative;
+	pd->last_proportional	= proportional;
+	pd->last_change		= change;
+	pd->last_target		= target;
+}
+
+void bch2_pd_controller_init(struct bch_pd_controller *pd)
+{
+	pd->rate.rate		= 1024;
+	pd->last_update		= jiffies;
+	pd->p_term_inverse	= 6000;
+	pd->d_term		= 30;
+	pd->d_smooth		= pd->d_term;
+	pd->backpressure	= 1;
+}
+
+void bch2_pd_controller_debug_to_text(struct printbuf *out, struct bch_pd_controller *pd)
+{
+	if (!out->nr_tabstops)
+		printbuf_tabstop_push(out, 20);
+
+	prt_printf(out, "rate:");
+	prt_tab(out);
+	prt_human_readable_s64(out, pd->rate.rate);
+	prt_newline(out);
+
+	prt_printf(out, "target:");
+	prt_tab(out);
+	prt_human_readable_u64(out, pd->last_target);
+	prt_newline(out);
+
+	prt_printf(out, "actual:");
+	prt_tab(out);
+	prt_human_readable_u64(out, pd->last_actual);
+	prt_newline(out);
+
+	prt_printf(out, "proportional:");
+	prt_tab(out);
+	prt_human_readable_s64(out, pd->last_proportional);
+	prt_newline(out);
+
+	prt_printf(out, "derivative:");
+	prt_tab(out);
+	prt_human_readable_s64(out, pd->last_derivative);
+	prt_newline(out);
+
+	prt_printf(out, "change:");
+	prt_tab(out);
+	prt_human_readable_s64(out, pd->last_change);
+	prt_newline(out);
+
+	prt_printf(out, "next io:");
+	prt_tab(out);
+	prt_printf(out, "%llims", div64_s64(pd->rate.next - local_clock(), NSEC_PER_MSEC));
+	prt_newline(out);
+}
+
+/* misc: */
+
+void bch2_bio_map(struct bio *bio, void *base, size_t size)
+{
+	while (size) {
+		struct page *page = is_vmalloc_addr(base)
+				? vmalloc_to_page(base)
+				: virt_to_page(base);
+		unsigned offset = offset_in_page(base);
+		unsigned len = min_t(size_t, PAGE_SIZE - offset, size);
+
+		BUG_ON(!bio_add_page(bio, page, len, offset));
+		size -= len;
+		base += len;
+	}
+}
+
+int bch2_bio_alloc_pages(struct bio *bio, size_t size, gfp_t gfp_mask)
+{
+	while (size) {
+		struct page *page = alloc_pages(gfp_mask, 0);
+		unsigned len = min_t(size_t, PAGE_SIZE, size);
+
+		if (!page)
+			return -ENOMEM;
+
+		if (unlikely(!bio_add_page(bio, page, len, 0))) {
+			__free_page(page);
+			break;
+		}
+
+		size -= len;
+	}
+
+	return 0;
+}
+
+size_t bch2_rand_range(size_t max)
+{
+	size_t rand;
+
+	if (!max)
+		return 0;
+
+	do {
+		rand = get_random_long();
+		rand &= roundup_pow_of_two(max) - 1;
+	} while (rand >= max);
+
+	return rand;
+}
+
+void memcpy_to_bio(struct bio *dst, struct bvec_iter dst_iter, const void *src)
+{
+	struct bio_vec bv;
+	struct bvec_iter iter;
+
+	__bio_for_each_segment(bv, dst, iter, dst_iter) {
+		void *dstp = kmap_local_page(bv.bv_page);
+
+		memcpy(dstp + bv.bv_offset, src, bv.bv_len);
+		kunmap_local(dstp);
+
+		src += bv.bv_len;
+	}
+}
+
+void memcpy_from_bio(void *dst, struct bio *src, struct bvec_iter src_iter)
+{
+	struct bio_vec bv;
+	struct bvec_iter iter;
+
+	__bio_for_each_segment(bv, src, iter, src_iter) {
+		void *srcp = kmap_local_page(bv.bv_page);
+
+		memcpy(dst, srcp + bv.bv_offset, bv.bv_len);
+		kunmap_local(srcp);
+
+		dst += bv.bv_len;
+	}
+}
+
+static int alignment_ok(const void *base, size_t align)
+{
+	return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ||
+		((unsigned long)base & (align - 1)) == 0;
+}
+
+static void u32_swap(void *a, void *b, size_t size)
+{
+	u32 t = *(u32 *)a;
+	*(u32 *)a = *(u32 *)b;
+	*(u32 *)b = t;
+}
+
+static void u64_swap(void *a, void *b, size_t size)
+{
+	u64 t = *(u64 *)a;
+	*(u64 *)a = *(u64 *)b;
+	*(u64 *)b = t;
+}
+
+static void generic_swap(void *a, void *b, size_t size)
+{
+	char t;
+
+	do {
+		t = *(char *)a;
+		*(char *)a++ = *(char *)b;
+		*(char *)b++ = t;
+	} while (--size > 0);
+}
+
+static inline int do_cmp(void *base, size_t n, size_t size,
+			 int (*cmp_func)(const void *, const void *, size_t),
+			 size_t l, size_t r)
+{
+	return cmp_func(base + inorder_to_eytzinger0(l, n) * size,
+			base + inorder_to_eytzinger0(r, n) * size,
+			size);
+}
+
+static inline void do_swap(void *base, size_t n, size_t size,
+			   void (*swap_func)(void *, void *, size_t),
+			   size_t l, size_t r)
+{
+	swap_func(base + inorder_to_eytzinger0(l, n) * size,
+		  base + inorder_to_eytzinger0(r, n) * size,
+		  size);
+}
+
+void eytzinger0_sort(void *base, size_t n, size_t size,
+		     int (*cmp_func)(const void *, const void *, size_t),
+		     void (*swap_func)(void *, void *, size_t))
+{
+	int i, c, r;
+
+	if (!swap_func) {
+		if (size == 4 && alignment_ok(base, 4))
+			swap_func = u32_swap;
+		else if (size == 8 && alignment_ok(base, 8))
+			swap_func = u64_swap;
+		else
+			swap_func = generic_swap;
+	}
+
+	/* heapify */
+	for (i = n / 2 - 1; i >= 0; --i) {
+		for (r = i; r * 2 + 1 < n; r = c) {
+			c = r * 2 + 1;
+
+			if (c + 1 < n &&
+			    do_cmp(base, n, size, cmp_func, c, c + 1) < 0)
+				c++;
+
+			if (do_cmp(base, n, size, cmp_func, r, c) >= 0)
+				break;
+
+			do_swap(base, n, size, swap_func, r, c);
+		}
+	}
+
+	/* sort */
+	for (i = n - 1; i > 0; --i) {
+		do_swap(base, n, size, swap_func, 0, i);
+
+		for (r = 0; r * 2 + 1 < i; r = c) {
+			c = r * 2 + 1;
+
+			if (c + 1 < i &&
+			    do_cmp(base, n, size, cmp_func, c, c + 1) < 0)
+				c++;
+
+			if (do_cmp(base, n, size, cmp_func, r, c) >= 0)
+				break;
+
+			do_swap(base, n, size, swap_func, r, c);
+		}
+	}
+}
+
+void sort_cmp_size(void *base, size_t num, size_t size,
+	  int (*cmp_func)(const void *, const void *, size_t),
+	  void (*swap_func)(void *, void *, size_t size))
+{
+	/* pre-scale counters for performance */
+	int i = (num/2 - 1) * size, n = num * size, c, r;
+
+	if (!swap_func) {
+		if (size == 4 && alignment_ok(base, 4))
+			swap_func = u32_swap;
+		else if (size == 8 && alignment_ok(base, 8))
+			swap_func = u64_swap;
+		else
+			swap_func = generic_swap;
+	}
+
+	/* heapify */
+	for ( ; i >= 0; i -= size) {
+		for (r = i; r * 2 + size < n; r  = c) {
+			c = r * 2 + size;
+			if (c < n - size &&
+			    cmp_func(base + c, base + c + size, size) < 0)
+				c += size;
+			if (cmp_func(base + r, base + c, size) >= 0)
+				break;
+			swap_func(base + r, base + c, size);
+		}
+	}
+
+	/* sort */
+	for (i = n - size; i > 0; i -= size) {
+		swap_func(base, base + i, size);
+		for (r = 0; r * 2 + size < i; r = c) {
+			c = r * 2 + size;
+			if (c < i - size &&
+			    cmp_func(base + c, base + c + size, size) < 0)
+				c += size;
+			if (cmp_func(base + r, base + c, size) >= 0)
+				break;
+			swap_func(base + r, base + c, size);
+		}
+	}
+}
+
+static void mempool_free_vp(void *element, void *pool_data)
+{
+	size_t size = (size_t) pool_data;
+
+	vpfree(element, size);
+}
+
+static void *mempool_alloc_vp(gfp_t gfp_mask, void *pool_data)
+{
+	size_t size = (size_t) pool_data;
+
+	return vpmalloc(size, gfp_mask);
+}
+
+int mempool_init_kvpmalloc_pool(mempool_t *pool, int min_nr, size_t size)
+{
+	return size < PAGE_SIZE
+		? mempool_init_kmalloc_pool(pool, min_nr, size)
+		: mempool_init(pool, min_nr, mempool_alloc_vp,
+			       mempool_free_vp, (void *) size);
+}
+
+#if 0
+void eytzinger1_test(void)
+{
+	unsigned inorder, eytz, size;
+
+	pr_info("1 based eytzinger test:");
+
+	for (size = 2;
+	     size < 65536;
+	     size++) {
+		unsigned extra = eytzinger1_extra(size);
+
+		if (!(size % 4096))
+			pr_info("tree size %u", size);
+
+		BUG_ON(eytzinger1_prev(0, size) != eytzinger1_last(size));
+		BUG_ON(eytzinger1_next(0, size) != eytzinger1_first(size));
+
+		BUG_ON(eytzinger1_prev(eytzinger1_first(size), size)	!= 0);
+		BUG_ON(eytzinger1_next(eytzinger1_last(size), size)	!= 0);
+
+		inorder = 1;
+		eytzinger1_for_each(eytz, size) {
+			BUG_ON(__inorder_to_eytzinger1(inorder, size, extra) != eytz);
+			BUG_ON(__eytzinger1_to_inorder(eytz, size, extra) != inorder);
+			BUG_ON(eytz != eytzinger1_last(size) &&
+			       eytzinger1_prev(eytzinger1_next(eytz, size), size) != eytz);
+
+			inorder++;
+		}
+	}
+}
+
+void eytzinger0_test(void)
+{
+
+	unsigned inorder, eytz, size;
+
+	pr_info("0 based eytzinger test:");
+
+	for (size = 1;
+	     size < 65536;
+	     size++) {
+		unsigned extra = eytzinger0_extra(size);
+
+		if (!(size % 4096))
+			pr_info("tree size %u", size);
+
+		BUG_ON(eytzinger0_prev(-1, size) != eytzinger0_last(size));
+		BUG_ON(eytzinger0_next(-1, size) != eytzinger0_first(size));
+
+		BUG_ON(eytzinger0_prev(eytzinger0_first(size), size)	!= -1);
+		BUG_ON(eytzinger0_next(eytzinger0_last(size), size)	!= -1);
+
+		inorder = 0;
+		eytzinger0_for_each(eytz, size) {
+			BUG_ON(__inorder_to_eytzinger0(inorder, size, extra) != eytz);
+			BUG_ON(__eytzinger0_to_inorder(eytz, size, extra) != inorder);
+			BUG_ON(eytz != eytzinger0_last(size) &&
+			       eytzinger0_prev(eytzinger0_next(eytz, size), size) != eytz);
+
+			inorder++;
+		}
+	}
+}
+
+static inline int cmp_u16(const void *_l, const void *_r, size_t size)
+{
+	const u16 *l = _l, *r = _r;
+
+	return (*l > *r) - (*r - *l);
+}
+
+static void eytzinger0_find_test_val(u16 *test_array, unsigned nr, u16 search)
+{
+	int i, c1 = -1, c2 = -1;
+	ssize_t r;
+
+	r = eytzinger0_find_le(test_array, nr,
+			       sizeof(test_array[0]),
+			       cmp_u16, &search);
+	if (r >= 0)
+		c1 = test_array[r];
+
+	for (i = 0; i < nr; i++)
+		if (test_array[i] <= search && test_array[i] > c2)
+			c2 = test_array[i];
+
+	if (c1 != c2) {
+		eytzinger0_for_each(i, nr)
+			pr_info("[%3u] = %12u", i, test_array[i]);
+		pr_info("find_le(%2u) -> [%2zi] = %2i should be %2i",
+			i, r, c1, c2);
+	}
+}
+
+void eytzinger0_find_test(void)
+{
+	unsigned i, nr, allocated = 1 << 12;
+	u16 *test_array = kmalloc_array(allocated, sizeof(test_array[0]), GFP_KERNEL);
+
+	for (nr = 1; nr < allocated; nr++) {
+		pr_info("testing %u elems", nr);
+
+		get_random_bytes(test_array, nr * sizeof(test_array[0]));
+		eytzinger0_sort(test_array, nr, sizeof(test_array[0]), cmp_u16, NULL);
+
+		/* verify array is sorted correctly: */
+		eytzinger0_for_each(i, nr)
+			BUG_ON(i != eytzinger0_last(nr) &&
+			       test_array[i] > test_array[eytzinger0_next(i, nr)]);
+
+		for (i = 0; i < U16_MAX; i += 1 << 12)
+			eytzinger0_find_test_val(test_array, nr, i);
+
+		for (i = 0; i < nr; i++) {
+			eytzinger0_find_test_val(test_array, nr, test_array[i] - 1);
+			eytzinger0_find_test_val(test_array, nr, test_array[i]);
+			eytzinger0_find_test_val(test_array, nr, test_array[i] + 1);
+		}
+	}
+
+	kfree(test_array);
+}
+#endif
+
+/*
+ * Accumulate percpu counters onto one cpu's copy - only valid when access
+ * against any percpu counter is guarded against
+ */
+u64 *bch2_acc_percpu_u64s(u64 __percpu *p, unsigned nr)
+{
+	u64 *ret;
+	int cpu;
+
+	/* access to pcpu vars has to be blocked by other locking */
+	preempt_disable();
+	ret = this_cpu_ptr(p);
+	preempt_enable();
+
+	for_each_possible_cpu(cpu) {
+		u64 *i = per_cpu_ptr(p, cpu);
+
+		if (i != ret) {
+			acc_u64s(ret, i, nr);
+			memset(i, 0, nr * sizeof(u64));
+		}
+	}
+
+	return ret;
+}