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