// SPDX-License-Identifier: GPL-2.0
/*
* random utility code, for bcache but in theory not specific to bcache
*
* Copyright 2010, 2011 Kent Overstreet <[email protected]>
* 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;
}
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