288 lines
6.4 KiB
C
288 lines
6.4 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* random utiility code, for bcache but in theory not specific to bcache
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*
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* Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
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* Copyright 2012 Google, Inc.
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*/
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/ctype.h>
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#include <linux/debugfs.h>
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#include <linux/module.h>
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#include <linux/seq_file.h>
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#include <linux/types.h>
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#include <linux/sched/clock.h>
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#include "util.h"
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#define simple_strtoint(c, end, base) simple_strtol(c, end, base)
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#define simple_strtouint(c, end, base) simple_strtoul(c, end, base)
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#define STRTO_H(name, type) \
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int bch_ ## name ## _h(const char *cp, type *res) \
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{ \
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int u = 0; \
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char *e; \
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type i = simple_ ## name(cp, &e, 10); \
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\
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switch (tolower(*e)) { \
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default: \
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return -EINVAL; \
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case 'y': \
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case 'z': \
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u++; \
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fallthrough; \
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case 'e': \
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u++; \
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fallthrough; \
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case 'p': \
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u++; \
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fallthrough; \
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case 't': \
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u++; \
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fallthrough; \
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case 'g': \
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u++; \
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fallthrough; \
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case 'm': \
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u++; \
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fallthrough; \
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case 'k': \
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u++; \
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if (e++ == cp) \
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return -EINVAL; \
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fallthrough; \
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case '\n': \
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case '\0': \
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if (*e == '\n') \
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e++; \
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} \
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\
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if (*e) \
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return -EINVAL; \
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\
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while (u--) { \
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if ((type) ~0 > 0 && \
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(type) ~0 / 1024 <= i) \
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return -EINVAL; \
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if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) || \
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(i < 0 && -ANYSINT_MAX(type) / 1024 > i)) \
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return -EINVAL; \
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i *= 1024; \
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} \
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\
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*res = i; \
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return 0; \
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} \
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STRTO_H(strtoint, int)
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STRTO_H(strtouint, unsigned int)
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STRTO_H(strtoll, long long)
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STRTO_H(strtoull, unsigned long long)
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/**
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* bch_hprint - formats @v to human readable string for sysfs.
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* @buf: the (at least 8 byte) buffer to format the result into.
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* @v: signed 64 bit integer
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*
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* Returns the number of bytes used by format.
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*/
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ssize_t bch_hprint(char *buf, int64_t v)
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{
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static const char units[] = "?kMGTPEZY";
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int u = 0, t;
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uint64_t q;
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if (v < 0)
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q = -v;
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else
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q = v;
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/* For as long as the number is more than 3 digits, but at least
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* once, shift right / divide by 1024. Keep the remainder for
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* a digit after the decimal point.
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*/
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do {
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u++;
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t = q & ~(~0 << 10);
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q >>= 10;
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} while (q >= 1000);
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if (v < 0)
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/* '-', up to 3 digits, '.', 1 digit, 1 character, null;
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* yields 8 bytes.
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*/
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return sprintf(buf, "-%llu.%i%c", q, t * 10 / 1024, units[u]);
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else
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return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]);
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}
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bool bch_is_zero(const char *p, size_t n)
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{
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size_t i;
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for (i = 0; i < n; i++)
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if (p[i])
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return false;
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return true;
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}
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int bch_parse_uuid(const char *s, char *uuid)
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{
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size_t i, j, x;
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memset(uuid, 0, 16);
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for (i = 0, j = 0;
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i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;
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i++) {
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x = s[i] | 32;
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switch (x) {
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case '0'...'9':
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x -= '0';
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break;
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case 'a'...'f':
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x -= 'a' - 10;
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break;
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default:
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continue;
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}
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if (!(j & 1))
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x <<= 4;
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uuid[j++ >> 1] |= x;
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}
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return i;
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}
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void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
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{
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uint64_t now, duration, last;
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spin_lock(&stats->lock);
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now = local_clock();
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duration = time_after64(now, start_time)
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? now - start_time : 0;
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last = time_after64(now, stats->last)
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? now - stats->last : 0;
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stats->max_duration = max(stats->max_duration, duration);
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if (stats->last) {
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ewma_add(stats->average_duration, duration, 8, 8);
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if (stats->average_frequency)
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ewma_add(stats->average_frequency, last, 8, 8);
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else
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stats->average_frequency = last << 8;
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} else {
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stats->average_duration = duration << 8;
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}
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stats->last = now ?: 1;
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spin_unlock(&stats->lock);
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}
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/**
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* bch_next_delay() - update ratelimiting statistics and calculate next delay
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* @d: the struct bch_ratelimit to update
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* @done: the amount of work done, in arbitrary units
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*
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* Increment @d by the amount of work done, and return how long to delay in
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* jiffies until the next time to do some work.
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*/
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uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
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{
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uint64_t now = local_clock();
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d->next += div_u64(done * NSEC_PER_SEC, atomic_long_read(&d->rate));
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/* Bound the time. Don't let us fall further than 2 seconds behind
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* (this prevents unnecessary backlog that would make it impossible
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* to catch up). If we're ahead of the desired writeback rate,
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* don't let us sleep more than 2.5 seconds (so we can notice/respond
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* if the control system tells us to speed up!).
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*/
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if (time_before64(now + NSEC_PER_SEC * 5LLU / 2LLU, d->next))
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d->next = now + NSEC_PER_SEC * 5LLU / 2LLU;
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if (time_after64(now - NSEC_PER_SEC * 2, d->next))
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d->next = now - NSEC_PER_SEC * 2;
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return time_after64(d->next, now)
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? div_u64(d->next - now, NSEC_PER_SEC / HZ)
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: 0;
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}
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/*
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* Generally it isn't good to access .bi_io_vec and .bi_vcnt directly,
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* the preferred way is bio_add_page, but in this case, bch_bio_map()
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* supposes that the bvec table is empty, so it is safe to access
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* .bi_vcnt & .bi_io_vec in this way even after multipage bvec is
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* supported.
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*/
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void bch_bio_map(struct bio *bio, void *base)
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{
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size_t size = bio->bi_iter.bi_size;
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struct bio_vec *bv = bio->bi_io_vec;
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BUG_ON(!bio->bi_iter.bi_size);
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BUG_ON(bio->bi_vcnt);
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bv->bv_offset = base ? offset_in_page(base) : 0;
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goto start;
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for (; size; bio->bi_vcnt++, bv++) {
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bv->bv_offset = 0;
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start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset,
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size);
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if (base) {
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bv->bv_page = is_vmalloc_addr(base)
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? vmalloc_to_page(base)
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: virt_to_page(base);
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base += bv->bv_len;
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}
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size -= bv->bv_len;
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}
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}
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/**
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* bch_bio_alloc_pages - allocates a single page for each bvec in a bio
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* @bio: bio to allocate pages for
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* @gfp_mask: flags for allocation
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*
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* Allocates pages up to @bio->bi_vcnt.
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*
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* Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
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* freed.
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*/
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int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
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{
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int i;
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struct bio_vec *bv;
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/*
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* This is called on freshly new bio, so it is safe to access the
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* bvec table directly.
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*/
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for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++, i++) {
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bv->bv_page = alloc_page(gfp_mask);
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if (!bv->bv_page) {
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while (--bv >= bio->bi_io_vec)
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__free_page(bv->bv_page);
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return -ENOMEM;
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}
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}
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return 0;
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}
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