// SPDX-License-Identifier: GPL-2.0/* * random utility 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/ctype.h>#include <linux/debugfs.h>#include <linux/module.h>#include <linux/seq_file.h>#include <linux/types.h>#include <linux/sched/clock.h> #include "util.h" #define simple_strtoint(c, end, base)	simple_strtol(c, end, base)#define simple_strtouint(c, end, base)	simple_strtoul(c, end, base) #define STRTO_H(name, type)					\int bch_ ## name ## _h(const char *cp, type *res)		\{								\	int u = 0;						\	char *e;						\	type i = simple_ ## name(cp, &e, 10);			\								\	switch (tolower(*e)) {					\	default:						\		return -EINVAL;					\	case 'y':						\	case 'z':						\		u++;						\		fallthrough;					\	case 'e':						\		u++;						\		fallthrough;					\	case 'p':						\		u++;						\		fallthrough;					\	case 't':						\		u++;						\		fallthrough;					\	case 'g':						\		u++;						\		fallthrough;					\	case 'm':						\		u++;						\		fallthrough;					\	case 'k':						\		u++;						\		if (e++ == cp)					\			return -EINVAL;				\		fallthrough;					\	case '\n':						\	case '\0':						\		if (*e == '\n')					\			e++;					\	}							\								\	if (*e)							\		return -EINVAL;					\								\	while (u--) {						\		if ((type) ~0 > 0 &&				\		    (type) ~0 / 1024 <= i)			\			return -EINVAL;				\		if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) ||	\		    (i < 0 && -ANYSINT_MAX(type) / 1024 > i))	\			return -EINVAL;				\		i *= 1024;					\	}							\								\	*res = i;						\	return 0;						\}								\ STRTO_H(strtoint, int)STRTO_H(strtouint, unsigned int)STRTO_H(strtoll, long long)STRTO_H(strtoull, unsigned long long) /** * bch_hprint - formats @v to human readable string for sysfs. * @buf: the (at least 8 byte) buffer to format the result into. * @v: signed 64 bit integer * * Returns the number of bytes used by format. */ssize_t bch_hprint(char *buf, int64_t v){	static const char units[] = "?kMGTPEZY";	int u = 0, t; 	uint64_t q; 	if (v < 0)		q = -v;	else		q = v; 	/* For as long as the number is more than 3 digits, but at least	 * once, shift right / divide by 1024.  Keep the remainder for	 * a digit after the decimal point.	 */	do {		u++; 		t = q & ~(~0 << 10);		q >>= 10;	} while (q >= 1000); 	if (v < 0)		/* '-', up to 3 digits, '.', 1 digit, 1 character, null;		 * yields 8 bytes.		 */		return sprintf(buf, "-%llu.%i%c", q, t * 10 / 1024, units[u]);	else		return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]);} bool bch_is_zero(const char *p, size_t n){	size_t i; 	for (i = 0; i < n; i++)		if (p[i])			return false;	return true;} int bch_parse_uuid(const char *s, char *uuid){	size_t i, j, x; 	memset(uuid, 0, 16); 	for (i = 0, j = 0;	     i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;	     i++) {		x = s[i] | 32; 		switch (x) {		case '0'...'9':			x -= '0';			break;		case 'a'...'f':			x -= 'a' - 10;			break;		default:			continue;		} 		if (!(j & 1))			x <<= 4;		uuid[j++ >> 1] |= x;	}	return i;} void bch_time_stats_update(struct time_stats *stats, uint64_t start_time){	uint64_t now, duration, last; 	spin_lock(&stats->lock); 	now		= local_clock();	duration	= time_after64(now, start_time)		? now - start_time : 0;	last		= time_after64(now, stats->last)		? now - stats->last : 0; 	stats->max_duration = max(stats->max_duration, duration); 	if (stats->last) {		ewma_add(stats->average_duration, duration, 8, 8); 		if (stats->average_frequency)			ewma_add(stats->average_frequency, last, 8, 8);		else			stats->average_frequency  = last << 8;	} else {		stats->average_duration  = duration << 8;	} 	stats->last = now ?: 1; 	spin_unlock(&stats->lock);} /** * bch_next_delay() - update ratelimiting statistics and calculate next delay * @d: the struct bch_ratelimit to update * @done: the amount of work done, in arbitrary units * * Increment @d by the amount of work done, and return how long to delay in * jiffies until the next time to do some work. */uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done){	uint64_t now = local_clock(); 	d->next += div_u64(done * NSEC_PER_SEC, atomic_long_read(&d->rate)); 	/* Bound the time.  Don't let us fall further than 2 seconds behind	 * (this prevents unnecessary backlog that would make it impossible	 * to catch up).  If we're ahead of the desired writeback rate,	 * don't let us sleep more than 2.5 seconds (so we can notice/respond	 * if the control system tells us to speed up!).	 */	if (time_before64(now + NSEC_PER_SEC * 5LLU / 2LLU, d->next))		d->next = now + NSEC_PER_SEC * 5LLU / 2LLU; 	if (time_after64(now - NSEC_PER_SEC * 2, d->next))		d->next = now - NSEC_PER_SEC * 2; 	return time_after64(d->next, now)		? div_u64(d->next - now, NSEC_PER_SEC / HZ)		: 0;} /* * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly, * the preferred way is bio_add_page, but in this case, bch_bio_map() * supposes that the bvec table is empty, so it is safe to access * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is * supported. */void bch_bio_map(struct bio *bio, void *base){	size_t size = bio->bi_iter.bi_size;	struct bio_vec *bv = bio->bi_io_vec; 	BUG_ON(!bio->bi_iter.bi_size);	BUG_ON(bio->bi_vcnt); 	bv->bv_offset = base ? offset_in_page(base) : 0;	goto start; 	for (; size; bio->bi_vcnt++, bv++) {		bv->bv_offset	= 0;start:		bv->bv_len	= min_t(size_t, PAGE_SIZE - bv->bv_offset,					size);		if (base) {			bv->bv_page = is_vmalloc_addr(base)				? vmalloc_to_page(base)				: virt_to_page(base); 			base += bv->bv_len;		} 		size -= bv->bv_len;	}} /** * bch_bio_alloc_pages - allocates a single page for each bvec in a bio * @bio: bio to allocate pages for * @gfp_mask: flags for allocation * * Allocates pages up to @bio->bi_vcnt. * * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are * freed. */int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask){	int i;	struct bio_vec *bv; 	/*	 * This is called on freshly new bio, so it is safe to access the	 * bvec table directly.	 */	for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++, i++) {		bv->bv_page = alloc_page(gfp_mask);		if (!bv->bv_page) {			while (--bv >= bio->bi_io_vec)				__free_page(bv->bv_page);			return -ENOMEM;		}	} 	return 0;}