linux/drivers/md/bcache/util.c
Ming Lei 2e1f4f4d24 bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()
bch_bio_alloc_pages() is always called on one new bio, so it is safe
to access the bvec table directly. Given it is the only kind of this
case, open code the bvec table access since bio_for_each_segment_all()
will be changed to support for iterating over multipage bvec.

Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-15 08:40:11 -07:00

288 lines
6.4 KiB
C

// 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/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++; \
/* fall through */ \
case 'e': \
u++; \
/* fall through */ \
case 'p': \
u++; \
/* fall through */ \
case 't': \
u++; \
/* fall through */ \
case 'g': \
u++; \
/* fall through */ \
case 'm': \
u++; \
/* fall through */ \
case 'k': \
u++; \
if (e++ == cp) \
return -EINVAL; \
/* fall through */ \
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;
}