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1// SPDX-License-Identifier: GPL-2.02/*3 * random utility code, for bcache but in theory not specific to bcache4 *5 * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>6 * Copyright 2012 Google, Inc.7 */8 9#include <linux/bio.h>10#include <linux/blkdev.h>11#include <linux/ctype.h>12#include <linux/debugfs.h>13#include <linux/module.h>14#include <linux/seq_file.h>15#include <linux/types.h>16#include <linux/sched/clock.h>17 18#include "util.h"19 20#define simple_strtoint(c, end, base) simple_strtol(c, end, base)21#define simple_strtouint(c, end, base) simple_strtoul(c, end, base)22 23#define STRTO_H(name, type) \24int bch_ ## name ## _h(const char *cp, type *res) \25{ \26 int u = 0; \27 char *e; \28 type i = simple_ ## name(cp, &e, 10); \29 \30 switch (tolower(*e)) { \31 default: \32 return -EINVAL; \33 case 'y': \34 case 'z': \35 u++; \36 fallthrough; \37 case 'e': \38 u++; \39 fallthrough; \40 case 'p': \41 u++; \42 fallthrough; \43 case 't': \44 u++; \45 fallthrough; \46 case 'g': \47 u++; \48 fallthrough; \49 case 'm': \50 u++; \51 fallthrough; \52 case 'k': \53 u++; \54 if (e++ == cp) \55 return -EINVAL; \56 fallthrough; \57 case '\n': \58 case '\0': \59 if (*e == '\n') \60 e++; \61 } \62 \63 if (*e) \64 return -EINVAL; \65 \66 while (u--) { \67 if ((type) ~0 > 0 && \68 (type) ~0 / 1024 <= i) \69 return -EINVAL; \70 if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) || \71 (i < 0 && -ANYSINT_MAX(type) / 1024 > i)) \72 return -EINVAL; \73 i *= 1024; \74 } \75 \76 *res = i; \77 return 0; \78} \79 80STRTO_H(strtoint, int)81STRTO_H(strtouint, unsigned int)82STRTO_H(strtoll, long long)83STRTO_H(strtoull, unsigned long long)84 85/**86 * bch_hprint - formats @v to human readable string for sysfs.87 * @buf: the (at least 8 byte) buffer to format the result into.88 * @v: signed 64 bit integer89 *90 * Returns the number of bytes used by format.91 */92ssize_t bch_hprint(char *buf, int64_t v)93{94 static const char units[] = "?kMGTPEZY";95 int u = 0, t;96 97 uint64_t q;98 99 if (v < 0)100 q = -v;101 else102 q = v;103 104 /* For as long as the number is more than 3 digits, but at least105 * once, shift right / divide by 1024. Keep the remainder for106 * a digit after the decimal point.107 */108 do {109 u++;110 111 t = q & ~(~0 << 10);112 q >>= 10;113 } while (q >= 1000);114 115 if (v < 0)116 /* '-', up to 3 digits, '.', 1 digit, 1 character, null;117 * yields 8 bytes.118 */119 return sprintf(buf, "-%llu.%i%c", q, t * 10 / 1024, units[u]);120 else121 return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]);122}123 124bool bch_is_zero(const char *p, size_t n)125{126 size_t i;127 128 for (i = 0; i < n; i++)129 if (p[i])130 return false;131 return true;132}133 134int bch_parse_uuid(const char *s, char *uuid)135{136 size_t i, j, x;137 138 memset(uuid, 0, 16);139 140 for (i = 0, j = 0;141 i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;142 i++) {143 x = s[i] | 32;144 145 switch (x) {146 case '0'...'9':147 x -= '0';148 break;149 case 'a'...'f':150 x -= 'a' - 10;151 break;152 default:153 continue;154 }155 156 if (!(j & 1))157 x <<= 4;158 uuid[j++ >> 1] |= x;159 }160 return i;161}162 163void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)164{165 uint64_t now, duration, last;166 167 spin_lock(&stats->lock);168 169 now = local_clock();170 duration = time_after64(now, start_time)171 ? now - start_time : 0;172 last = time_after64(now, stats->last)173 ? now - stats->last : 0;174 175 stats->max_duration = max(stats->max_duration, duration);176 177 if (stats->last) {178 ewma_add(stats->average_duration, duration, 8, 8);179 180 if (stats->average_frequency)181 ewma_add(stats->average_frequency, last, 8, 8);182 else183 stats->average_frequency = last << 8;184 } else {185 stats->average_duration = duration << 8;186 }187 188 stats->last = now ?: 1;189 190 spin_unlock(&stats->lock);191}192 193/**194 * bch_next_delay() - update ratelimiting statistics and calculate next delay195 * @d: the struct bch_ratelimit to update196 * @done: the amount of work done, in arbitrary units197 *198 * Increment @d by the amount of work done, and return how long to delay in199 * jiffies until the next time to do some work.200 */201uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)202{203 uint64_t now = local_clock();204 205 d->next += div_u64(done * NSEC_PER_SEC, atomic_long_read(&d->rate));206 207 /* Bound the time. Don't let us fall further than 2 seconds behind208 * (this prevents unnecessary backlog that would make it impossible209 * to catch up). If we're ahead of the desired writeback rate,210 * don't let us sleep more than 2.5 seconds (so we can notice/respond211 * if the control system tells us to speed up!).212 */213 if (time_before64(now + NSEC_PER_SEC * 5LLU / 2LLU, d->next))214 d->next = now + NSEC_PER_SEC * 5LLU / 2LLU;215 216 if (time_after64(now - NSEC_PER_SEC * 2, d->next))217 d->next = now - NSEC_PER_SEC * 2;218 219 return time_after64(d->next, now)220 ? div_u64(d->next - now, NSEC_PER_SEC / HZ)221 : 0;222}223 224/*225 * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly,226 * the preferred way is bio_add_page, but in this case, bch_bio_map()227 * supposes that the bvec table is empty, so it is safe to access228 * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is229 * supported.230 */231void bch_bio_map(struct bio *bio, void *base)232{233 size_t size = bio->bi_iter.bi_size;234 struct bio_vec *bv = bio->bi_io_vec;235 236 BUG_ON(!bio->bi_iter.bi_size);237 BUG_ON(bio->bi_vcnt);238 239 bv->bv_offset = base ? offset_in_page(base) : 0;240 goto start;241 242 for (; size; bio->bi_vcnt++, bv++) {243 bv->bv_offset = 0;244start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset,245 size);246 if (base) {247 bv->bv_page = is_vmalloc_addr(base)248 ? vmalloc_to_page(base)249 : virt_to_page(base);250 251 base += bv->bv_len;252 }253 254 size -= bv->bv_len;255 }256}257 258/**259 * bch_bio_alloc_pages - allocates a single page for each bvec in a bio260 * @bio: bio to allocate pages for261 * @gfp_mask: flags for allocation262 *263 * Allocates pages up to @bio->bi_vcnt.264 *265 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are266 * freed.267 */268int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)269{270 int i;271 struct bio_vec *bv;272 273 /*274 * This is called on freshly new bio, so it is safe to access the275 * bvec table directly.276 */277 for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++, i++) {278 bv->bv_page = alloc_page(gfp_mask);279 if (!bv->bv_page) {280 while (--bv >= bio->bi_io_vec)281 __free_page(bv->bv_page);282 return -ENOMEM;283 }284 }285 286 return 0;287}288