drivers/md/bcache/util.c

   1 /*
   2  * random utiility code, for bcache but in theory not specific to bcache
   3  *
   4  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   5  * Copyright 2012 Google, Inc.
   6  */
   7
   8 #include <linux/bio.h>
   9 #include <linux/blkdev.h>
  10 #include <linux/ctype.h>
  11 #include <linux/debugfs.h>
  12 #include <linux/module.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/types.h>
  15 #include <linux/sched/clock.h>
  16
  17 #include "util.h"
  18
  19 #define simple_strtoint(c, end, base)   simple_strtol(c, end, base)
  20 #define simple_strtouint(c, end, base)  simple_strtoul(c, end, base)
  21
  22 #define STRTO_H(name, type)                                     \
  23 int bch_ ## name ## _h(const char *cp, type *res)               \
  24 {                                                               \
  25         int u = 0;                                              \
  26         char *e;                                                \
  27         type i = simple_ ## name(cp, &e, 10);                   \
  28                                                                 \
  29         switch (tolower(*e)) {                                  \
  30         default:                                                \
  31                 return -EINVAL;                                 \
  32         case 'y':                                               \
  33         case 'z':                                               \
  34                 u++;                                            \
  35                 /* fall through */                              \
  36         case 'e':                                               \
  37                 u++;                                            \
  38                 /* fall through */                              \
  39         case 'p':                                               \
  40                 u++;                                            \
  41                 /* fall through */                              \
  42         case 't':                                               \
  43                 u++;                                            \
  44                 /* fall through */                              \
  45         case 'g':                                               \
  46                 u++;                                            \
  47                 /* fall through */                              \
  48         case 'm':                                               \
  49                 u++;                                            \
  50                 /* fall through */                              \
  51         case 'k':                                               \
  52                 u++;                                            \
  53                 if (e++ == cp)                                  \
  54                         return -EINVAL;                         \
  55                 /* fall through */                              \
  56         case '\n':                                              \
  57         case '\0':                                              \
  58                 if (*e == '\n')                                 \
  59                         e++;                                    \
  60         }                                                       \
  61                                                                 \
  62         if (*e)                                                 \
  63                 return -EINVAL;                                 \
  64                                                                 \
  65         while (u--) {                                           \
  66                 if ((type) ~0 > 0 &&                            \
  67                     (type) ~0 / 1024 <= i)                      \
  68                         return -EINVAL;                         \
  69                 if ((i > 0 && ANYSINT_MAX(type) / 1024 < i) ||  \
  70                     (i < 0 && -ANYSINT_MAX(type) / 1024 > i))   \
  71                         return -EINVAL;                         \
  72                 i *= 1024;                                      \
  73         }                                                       \
  74                                                                 \
  75         *res = i;                                               \
  76         return 0;                                               \
  77 }                                                               \
  78
  79 STRTO_H(strtoint, int)
  80 STRTO_H(strtouint, unsigned int)
  81 STRTO_H(strtoll, long long)
  82 STRTO_H(strtoull, unsigned long long)
  83
  84 /**
  85  * bch_hprint - formats @v to human readable string for sysfs.
  86  * @buf: the (at least 8 byte) buffer to format the result into.
  87  * @v: signed 64 bit integer
  88  *
  89  * Returns the number of bytes used by format.
  90  */
  91 ssize_t bch_hprint(char *buf, int64_t v)
  92 {
  93         static const char units[] = "?kMGTPEZY";
  94         int u = 0, t;
  95
  96         uint64_t q;
  97
  98         if (v < 0)
  99                 q = -v;
 100         else
 101                 q = v;
 102
 103         /* For as long as the number is more than 3 digits, but at least
 104          * once, shift right / divide by 1024.  Keep the remainder for
 105          * a digit after the decimal point.
 106          */
 107         do {
 108                 u++;
 109
 110                 t = q & ~(~0 << 10);
 111                 q >>= 10;
 112         } while (q >= 1000);
 113
 114         if (v < 0)
 115                 /* '-', up to 3 digits, '.', 1 digit, 1 character, null;
 116                  * yields 8 bytes.
 117                  */
 118                 return sprintf(buf, "-%llu.%i%c", q, t * 10 / 1024, units[u]);
 119         else
 120                 return sprintf(buf, "%llu.%i%c", q, t * 10 / 1024, units[u]);
 121 }
 122
 123 bool bch_is_zero(const char *p, size_t n)
 124 {
 125         size_t i;
 126
 127         for (i = 0; i < n; i++)
 128                 if (p[i])
 129                         return false;
 130         return true;
 131 }
 132
 133 int bch_parse_uuid(const char *s, char *uuid)
 134 {
 135         size_t i, j, x;
 136
 137         memset(uuid, 0, 16);
 138
 139         for (i = 0, j = 0;
 140              i < strspn(s, "-0123456789:ABCDEFabcdef") && j < 32;
 141              i++) {
 142                 x = s[i] | 32;
 143
 144                 switch (x) {
 145                 case '0'...'9':
 146                         x -= '0';
 147                         break;
 148                 case 'a'...'f':
 149                         x -= 'a' - 10;
 150                         break;
 151                 default:
 152                         continue;
 153                 }
 154
 155                 if (!(j & 1))
 156                         x <<= 4;
 157                 uuid[j++ >> 1] |= x;
 158         }
 159         return i;
 160 }
 161
 162 void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
 163 {
 164         uint64_t now, duration, last;
 165
 166         spin_lock(&stats->lock);
 167
 168         now             = local_clock();
 169         duration        = time_after64(now, start_time)
 170                 ? now - start_time : 0;
 171         last            = time_after64(now, stats->last)
 172                 ? now - stats->last : 0;
 173
 174         stats->max_duration = max(stats->max_duration, duration);
 175
 176         if (stats->last) {
 177                 ewma_add(stats->average_duration, duration, 8, 8);
 178
 179                 if (stats->average_frequency)
 180                         ewma_add(stats->average_frequency, last, 8, 8);
 181                 else
 182                         stats->average_frequency  = last << 8;
 183         } else {
 184                 stats->average_duration  = duration << 8;
 185         }
 186
 187         stats->last = now ?: 1;
 188
 189         spin_unlock(&stats->lock);
 190 }
 191
 192 /**
 193  * bch_next_delay() - update ratelimiting statistics and calculate next delay
 194  * @d: the struct bch_ratelimit to update
 195  * @done: the amount of work done, in arbitrary units
 196  *
 197  * Increment @d by the amount of work done, and return how long to delay in
 198  * jiffies until the next time to do some work.
 199  */
 200 uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
 201 {
 202         uint64_t now = local_clock();
 203
 204         d->next += div_u64(done * NSEC_PER_SEC, atomic_long_read(&d->rate));
 205
 206         /* Bound the time.  Don't let us fall further than 2 seconds behind
 207          * (this prevents unnecessary backlog that would make it impossible
 208          * to catch up).  If we're ahead of the desired writeback rate,
 209          * don't let us sleep more than 2.5 seconds (so we can notice/respond
 210          * if the control system tells us to speed up!).
 211          */
 212         if (time_before64(now + NSEC_PER_SEC * 5LLU / 2LLU, d->next))
 213                 d->next = now + NSEC_PER_SEC * 5LLU / 2LLU;
 214
 215         if (time_after64(now - NSEC_PER_SEC * 2, d->next))
 216                 d->next = now - NSEC_PER_SEC * 2;
 217
 218         return time_after64(d->next, now)
 219                 ? div_u64(d->next - now, NSEC_PER_SEC / HZ)
 220                 : 0;
 221 }
 222
 223 /*
 224  * Generally it isn't good to access .bi_io_vec and .bi_vcnt directly,
 225  * the preferred way is bio_add_page, but in this case, bch_bio_map()
 226  * supposes that the bvec table is empty, so it is safe to access
 227  * .bi_vcnt & .bi_io_vec in this way even after multipage bvec is
 228  * supported.
 229  */
 230 void bch_bio_map(struct bio *bio, void *base)
 231 {
 232         size_t size = bio->bi_iter.bi_size;
 233         struct bio_vec *bv = bio->bi_io_vec;
 234
 235         BUG_ON(!bio->bi_iter.bi_size);
 236         BUG_ON(bio->bi_vcnt);
 237
 238         bv->bv_offset = base ? offset_in_page(base) : 0;
 239         goto start;
 240
 241         for (; size; bio->bi_vcnt++, bv++) {
 242                 bv->bv_offset   = 0;
 243 start:          bv->bv_len      = min_t(size_t, PAGE_SIZE - bv->bv_offset,
 244                                         size);
 245                 if (base) {
 246                         bv->bv_page = is_vmalloc_addr(base)
 247                                 ? vmalloc_to_page(base)
 248                                 : virt_to_page(base);
 249
 250                         base += bv->bv_len;
 251                 }
 252
 253                 size -= bv->bv_len;
 254         }
 255 }
 256
 257 /**
 258  * bch_bio_alloc_pages - allocates a single page for each bvec in a bio
 259  * @bio: bio to allocate pages for
 260  * @gfp_mask: flags for allocation
 261  *
 262  * Allocates pages up to @bio->bi_vcnt.
 263  *
 264  * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
 265  * freed.
 266  */
 267 int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
 268 {
 269         int i;
 270         struct bio_vec *bv;
 271
 272         bio_for_each_segment_all(bv, bio, i) {
 273                 bv->bv_page = alloc_page(gfp_mask);
 274                 if (!bv->bv_page) {
 275                         while (--bv >= bio->bi_io_vec)
 276                                 __free_page(bv->bv_page);
 277                         return -ENOMEM;
 278                 }
 279         }
 280
 281         return 0;
 282 }
 283
 284 /*
 285  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group (Any
 286  * use permitted, subject to terms of PostgreSQL license; see.)
 287
 288  * If we have a 64-bit integer type, then a 64-bit CRC looks just like the
 289  * usual sort of implementation. (See Ross Williams' excellent introduction
 290  * A PAINLESS GUIDE TO CRC ERROR DETECTION ALGORITHMS, available from
 291  * ftp://ftp.rocksoft.com/papers/crc_v3.txt or several other net sites.)
 292  * If we have no working 64-bit type, then fake it with two 32-bit registers.
 293  *
 294  * The present implementation is a normal (not "reflected", in Williams'
 295  * terms) 64-bit CRC, using initial all-ones register contents and a final
 296  * bit inversion. The chosen polynomial is borrowed from the DLT1 spec
 297  * (ECMA-182, available from http://www.ecma.ch/ecma1/STAND/ECMA-182.HTM):
 298  *
 299  * x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 +
 300  * x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 +
 301  * x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
 302  * x^7 + x^4 + x + 1
 303 */
 304
 305 static const uint64_t crc_table[256] = {
 306         0x0000000000000000ULL, 0x42F0E1EBA9EA3693ULL, 0x85E1C3D753D46D26ULL,
 307         0xC711223CFA3E5BB5ULL, 0x493366450E42ECDFULL, 0x0BC387AEA7A8DA4CULL,
 308         0xCCD2A5925D9681F9ULL, 0x8E224479F47CB76AULL, 0x9266CC8A1C85D9BEULL,
 309         0xD0962D61B56FEF2DULL, 0x17870F5D4F51B498ULL, 0x5577EEB6E6BB820BULL,
 310         0xDB55AACF12C73561ULL, 0x99A54B24BB2D03F2ULL, 0x5EB4691841135847ULL,
 311         0x1C4488F3E8F96ED4ULL, 0x663D78FF90E185EFULL, 0x24CD9914390BB37CULL,
 312         0xE3DCBB28C335E8C9ULL, 0xA12C5AC36ADFDE5AULL, 0x2F0E1EBA9EA36930ULL,
 313         0x6DFEFF5137495FA3ULL, 0xAAEFDD6DCD770416ULL, 0xE81F3C86649D3285ULL,
 314         0xF45BB4758C645C51ULL, 0xB6AB559E258E6AC2ULL, 0x71BA77A2DFB03177ULL,
 315         0x334A9649765A07E4ULL, 0xBD68D2308226B08EULL, 0xFF9833DB2BCC861DULL,
 316         0x388911E7D1F2DDA8ULL, 0x7A79F00C7818EB3BULL, 0xCC7AF1FF21C30BDEULL,
 317         0x8E8A101488293D4DULL, 0x499B3228721766F8ULL, 0x0B6BD3C3DBFD506BULL,
 318         0x854997BA2F81E701ULL, 0xC7B97651866BD192ULL, 0x00A8546D7C558A27ULL,
 319         0x4258B586D5BFBCB4ULL, 0x5E1C3D753D46D260ULL, 0x1CECDC9E94ACE4F3ULL,
 320         0xDBFDFEA26E92BF46ULL, 0x990D1F49C77889D5ULL, 0x172F5B3033043EBFULL,
 321         0x55DFBADB9AEE082CULL, 0x92CE98E760D05399ULL, 0xD03E790CC93A650AULL,
 322         0xAA478900B1228E31ULL, 0xE8B768EB18C8B8A2ULL, 0x2FA64AD7E2F6E317ULL,
 323         0x6D56AB3C4B1CD584ULL, 0xE374EF45BF6062EEULL, 0xA1840EAE168A547DULL,
 324         0x66952C92ECB40FC8ULL, 0x2465CD79455E395BULL, 0x3821458AADA7578FULL,
 325         0x7AD1A461044D611CULL, 0xBDC0865DFE733AA9ULL, 0xFF3067B657990C3AULL,
 326         0x711223CFA3E5BB50ULL, 0x33E2C2240A0F8DC3ULL, 0xF4F3E018F031D676ULL,
 327         0xB60301F359DBE0E5ULL, 0xDA050215EA6C212FULL, 0x98F5E3FE438617BCULL,
 328         0x5FE4C1C2B9B84C09ULL, 0x1D14202910527A9AULL, 0x93366450E42ECDF0ULL,
 329         0xD1C685BB4DC4FB63ULL, 0x16D7A787B7FAA0D6ULL, 0x5427466C1E109645ULL,
 330         0x4863CE9FF6E9F891ULL, 0x0A932F745F03CE02ULL, 0xCD820D48A53D95B7ULL,
 331         0x8F72ECA30CD7A324ULL, 0x0150A8DAF8AB144EULL, 0x43A04931514122DDULL,
 332         0x84B16B0DAB7F7968ULL, 0xC6418AE602954FFBULL, 0xBC387AEA7A8DA4C0ULL,
 333         0xFEC89B01D3679253ULL, 0x39D9B93D2959C9E6ULL, 0x7B2958D680B3FF75ULL,
 334         0xF50B1CAF74CF481FULL, 0xB7FBFD44DD257E8CULL, 0x70EADF78271B2539ULL,
 335         0x321A3E938EF113AAULL, 0x2E5EB66066087D7EULL, 0x6CAE578BCFE24BEDULL,
 336         0xABBF75B735DC1058ULL, 0xE94F945C9C3626CBULL, 0x676DD025684A91A1ULL,
 337         0x259D31CEC1A0A732ULL, 0xE28C13F23B9EFC87ULL, 0xA07CF2199274CA14ULL,
 338         0x167FF3EACBAF2AF1ULL, 0x548F120162451C62ULL, 0x939E303D987B47D7ULL,
 339         0xD16ED1D631917144ULL, 0x5F4C95AFC5EDC62EULL, 0x1DBC74446C07F0BDULL,
 340         0xDAAD56789639AB08ULL, 0x985DB7933FD39D9BULL, 0x84193F60D72AF34FULL,
 341         0xC6E9DE8B7EC0C5DCULL, 0x01F8FCB784FE9E69ULL, 0x43081D5C2D14A8FAULL,
 342         0xCD2A5925D9681F90ULL, 0x8FDAB8CE70822903ULL, 0x48CB9AF28ABC72B6ULL,
 343         0x0A3B7B1923564425ULL, 0x70428B155B4EAF1EULL, 0x32B26AFEF2A4998DULL,
 344         0xF5A348C2089AC238ULL, 0xB753A929A170F4ABULL, 0x3971ED50550C43C1ULL,
 345         0x7B810CBBFCE67552ULL, 0xBC902E8706D82EE7ULL, 0xFE60CF6CAF321874ULL,
 346         0xE224479F47CB76A0ULL, 0xA0D4A674EE214033ULL, 0x67C58448141F1B86ULL,
 347         0x253565A3BDF52D15ULL, 0xAB1721DA49899A7FULL, 0xE9E7C031E063ACECULL,
 348         0x2EF6E20D1A5DF759ULL, 0x6C0603E6B3B7C1CAULL, 0xF6FAE5C07D3274CDULL,
 349         0xB40A042BD4D8425EULL, 0x731B26172EE619EBULL, 0x31EBC7FC870C2F78ULL,
 350         0xBFC9838573709812ULL, 0xFD39626EDA9AAE81ULL, 0x3A28405220A4F534ULL,
 351         0x78D8A1B9894EC3A7ULL, 0x649C294A61B7AD73ULL, 0x266CC8A1C85D9BE0ULL,
 352         0xE17DEA9D3263C055ULL, 0xA38D0B769B89F6C6ULL, 0x2DAF4F0F6FF541ACULL,
 353         0x6F5FAEE4C61F773FULL, 0xA84E8CD83C212C8AULL, 0xEABE6D3395CB1A19ULL,
 354         0x90C79D3FEDD3F122ULL, 0xD2377CD44439C7B1ULL, 0x15265EE8BE079C04ULL,
 355         0x57D6BF0317EDAA97ULL, 0xD9F4FB7AE3911DFDULL, 0x9B041A914A7B2B6EULL,
 356         0x5C1538ADB04570DBULL, 0x1EE5D94619AF4648ULL, 0x02A151B5F156289CULL,
 357         0x4051B05E58BC1E0FULL, 0x87409262A28245BAULL, 0xC5B073890B687329ULL,
 358         0x4B9237F0FF14C443ULL, 0x0962D61B56FEF2D0ULL, 0xCE73F427ACC0A965ULL,
 359         0x8C8315CC052A9FF6ULL, 0x3A80143F5CF17F13ULL, 0x7870F5D4F51B4980ULL,
 360         0xBF61D7E80F251235ULL, 0xFD913603A6CF24A6ULL, 0x73B3727A52B393CCULL,
 361         0x31439391FB59A55FULL, 0xF652B1AD0167FEEAULL, 0xB4A25046A88DC879ULL,
 362         0xA8E6D8B54074A6ADULL, 0xEA16395EE99E903EULL, 0x2D071B6213A0CB8BULL,
 363         0x6FF7FA89BA4AFD18ULL, 0xE1D5BEF04E364A72ULL, 0xA3255F1BE7DC7CE1ULL,
 364         0x64347D271DE22754ULL, 0x26C49CCCB40811C7ULL, 0x5CBD6CC0CC10FAFCULL,
 365         0x1E4D8D2B65FACC6FULL, 0xD95CAF179FC497DAULL, 0x9BAC4EFC362EA149ULL,
 366         0x158E0A85C2521623ULL, 0x577EEB6E6BB820B0ULL, 0x906FC95291867B05ULL,
 367         0xD29F28B9386C4D96ULL, 0xCEDBA04AD0952342ULL, 0x8C2B41A1797F15D1ULL,
 368         0x4B3A639D83414E64ULL, 0x09CA82762AAB78F7ULL, 0x87E8C60FDED7CF9DULL,
 369         0xC51827E4773DF90EULL, 0x020905D88D03A2BBULL, 0x40F9E43324E99428ULL,
 370         0x2CFFE7D5975E55E2ULL, 0x6E0F063E3EB46371ULL, 0xA91E2402C48A38C4ULL,
 371         0xEBEEC5E96D600E57ULL, 0x65CC8190991CB93DULL, 0x273C607B30F68FAEULL,
 372         0xE02D4247CAC8D41BULL, 0xA2DDA3AC6322E288ULL, 0xBE992B5F8BDB8C5CULL,
 373         0xFC69CAB42231BACFULL, 0x3B78E888D80FE17AULL, 0x7988096371E5D7E9ULL,
 374         0xF7AA4D1A85996083ULL, 0xB55AACF12C735610ULL, 0x724B8ECDD64D0DA5ULL,
 375         0x30BB6F267FA73B36ULL, 0x4AC29F2A07BFD00DULL, 0x08327EC1AE55E69EULL,
 376         0xCF235CFD546BBD2BULL, 0x8DD3BD16FD818BB8ULL, 0x03F1F96F09FD3CD2ULL,
 377         0x41011884A0170A41ULL, 0x86103AB85A2951F4ULL, 0xC4E0DB53F3C36767ULL,
 378         0xD8A453A01B3A09B3ULL, 0x9A54B24BB2D03F20ULL, 0x5D45907748EE6495ULL,
 379         0x1FB5719CE1045206ULL, 0x919735E51578E56CULL, 0xD367D40EBC92D3FFULL,
 380         0x1476F63246AC884AULL, 0x568617D9EF46BED9ULL, 0xE085162AB69D5E3CULL,
 381         0xA275F7C11F7768AFULL, 0x6564D5FDE549331AULL, 0x279434164CA30589ULL,
 382         0xA9B6706FB8DFB2E3ULL, 0xEB46918411358470ULL, 0x2C57B3B8EB0BDFC5ULL,
 383         0x6EA7525342E1E956ULL, 0x72E3DAA0AA188782ULL, 0x30133B4B03F2B111ULL,
 384         0xF7021977F9CCEAA4ULL, 0xB5F2F89C5026DC37ULL, 0x3BD0BCE5A45A6B5DULL,
 385         0x79205D0E0DB05DCEULL, 0xBE317F32F78E067BULL, 0xFCC19ED95E6430E8ULL,
 386         0x86B86ED5267CDBD3ULL, 0xC4488F3E8F96ED40ULL, 0x0359AD0275A8B6F5ULL,
 387         0x41A94CE9DC428066ULL, 0xCF8B0890283E370CULL, 0x8D7BE97B81D4019FULL,
 388         0x4A6ACB477BEA5A2AULL, 0x089A2AACD2006CB9ULL, 0x14DEA25F3AF9026DULL,
 389         0x562E43B4931334FEULL, 0x913F6188692D6F4BULL, 0xD3CF8063C0C759D8ULL,
 390         0x5DEDC41A34BBEEB2ULL, 0x1F1D25F19D51D821ULL, 0xD80C07CD676F8394ULL,
 391         0x9AFCE626CE85B507ULL,
 392 };
 393
 394 uint64_t bch_crc64_update(uint64_t crc, const void *_data, size_t len)
 395 {
 396         const unsigned char *data = _data;
 397
 398         while (len--) {
 399                 int i = ((int) (crc >> 56) ^ *data++) & 0xFF;
 400                 crc = crc_table[i] ^ (crc << 8);
 401         }
 402
 403         return crc;
 404 }
 405
 406 uint64_t bch_crc64(const void *data, size_t len)
 407 {
 408         uint64_t crc = 0xffffffffffffffffULL;
 409
 410         crc = bch_crc64_update(crc, data, len);
 411
 412         return crc ^ 0xffffffffffffffffULL;
 413 }