1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * random utiility code, for bcache but in theory not specific to bcache 4 * 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) \ 24 int 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 /* fall through */ \ 37 case 'e': \ 38 u++; \ 39 /* fall through */ \ 40 case 'p': \ 41 u++; \ 42 /* fall through */ \ 43 case 't': \ 44 u++; \ 45 /* fall through */ \ 46 case 'g': \ 47 u++; \ 48 /* fall through */ \ 49 case 'm': \ 50 u++; \ 51 /* fall through */ \ 52 case 'k': \ 53 u++; \ 54 if (e++ == cp) \ 55 return -EINVAL; \ 56 /* fall through */ \ 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 80 STRTO_H(strtoint, int) 81 STRTO_H(strtouint, unsigned int) 82 STRTO_H(strtoll, long long) 83 STRTO_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 integer 89 * 90 * Returns the number of bytes used by format. 91 */ 92 ssize_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 else 102 q = v; 103 104 /* For as long as the number is more than 3 digits, but at least 105 * once, shift right / divide by 1024. Keep the remainder for 106 * 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 else 121 return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]); 122 } 123 124 bool 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 } 133 134 int 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 } 162 163 void 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 else 183 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 delay 195 * @d: the struct bch_ratelimit to update 196 * @done: the amount of work done, in arbitrary units 197 * 198 * Increment @d by the amount of work done, and return how long to delay in 199 * jiffies until the next time to do some work. 200 */ 201 uint64_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 behind 208 * (this prevents unnecessary backlog that would make it impossible 209 * 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/respond 211 * 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 access 228 * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is 229 * supported. 230 */ 231 void 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; 244 start: 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 bio 260 * @bio: bio to allocate pages for 261 * @gfp_mask: flags for allocation 262 * 263 * Allocates pages up to @bio->bi_vcnt. 264 * 265 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are 266 * freed. 267 */ 268 int 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 the 275 * 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