linux/lib/bitmap.c
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   1/*
   2 * lib/bitmap.c
   3 * Helper functions for bitmap.h.
   4 *
   5 * This source code is licensed under the GNU General Public License,
   6 * Version 2.  See the file COPYING for more details.
   7 */
   8#include <linux/module.h>
   9#include <linux/ctype.h>
  10#include <linux/errno.h>
  11#include <linux/bitmap.h>
  12#include <linux/bitops.h>
  13#include <asm/uaccess.h>
  14
  15/*
  16 * bitmaps provide an array of bits, implemented using an an
  17 * array of unsigned longs.  The number of valid bits in a
  18 * given bitmap does _not_ need to be an exact multiple of
  19 * BITS_PER_LONG.
  20 *
  21 * The possible unused bits in the last, partially used word
  22 * of a bitmap are 'don't care'.  The implementation makes
  23 * no particular effort to keep them zero.  It ensures that
  24 * their value will not affect the results of any operation.
  25 * The bitmap operations that return Boolean (bitmap_empty,
  26 * for example) or scalar (bitmap_weight, for example) results
  27 * carefully filter out these unused bits from impacting their
  28 * results.
  29 *
  30 * These operations actually hold to a slightly stronger rule:
  31 * if you don't input any bitmaps to these ops that have some
  32 * unused bits set, then they won't output any set unused bits
  33 * in output bitmaps.
  34 *
  35 * The byte ordering of bitmaps is more natural on little
  36 * endian architectures.  See the big-endian headers
  37 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
  38 * for the best explanations of this ordering.
  39 */
  40
  41int __bitmap_empty(const unsigned long *bitmap, int bits)
  42{
  43        int k, lim = bits/BITS_PER_LONG;
  44        for (k = 0; k < lim; ++k)
  45                if (bitmap[k])
  46                        return 0;
  47
  48        if (bits % BITS_PER_LONG)
  49                if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
  50                        return 0;
  51
  52        return 1;
  53}
  54EXPORT_SYMBOL(__bitmap_empty);
  55
  56int __bitmap_full(const unsigned long *bitmap, int bits)
  57{
  58        int k, lim = bits/BITS_PER_LONG;
  59        for (k = 0; k < lim; ++k)
  60                if (~bitmap[k])
  61                        return 0;
  62
  63        if (bits % BITS_PER_LONG)
  64                if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
  65                        return 0;
  66
  67        return 1;
  68}
  69EXPORT_SYMBOL(__bitmap_full);
  70
  71int __bitmap_equal(const unsigned long *bitmap1,
  72                const unsigned long *bitmap2, int bits)
  73{
  74        int k, lim = bits/BITS_PER_LONG;
  75        for (k = 0; k < lim; ++k)
  76                if (bitmap1[k] != bitmap2[k])
  77                        return 0;
  78
  79        if (bits % BITS_PER_LONG)
  80                if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
  81                        return 0;
  82
  83        return 1;
  84}
  85EXPORT_SYMBOL(__bitmap_equal);
  86
  87void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
  88{
  89        int k, lim = bits/BITS_PER_LONG;
  90        for (k = 0; k < lim; ++k)
  91                dst[k] = ~src[k];
  92
  93        if (bits % BITS_PER_LONG)
  94                dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
  95}
  96EXPORT_SYMBOL(__bitmap_complement);
  97
  98/**
  99 * __bitmap_shift_right - logical right shift of the bits in a bitmap
 100 *   @dst : destination bitmap
 101 *   @src : source bitmap
 102 *   @shift : shift by this many bits
 103 *   @bits : bitmap size, in bits
 104 *
 105 * Shifting right (dividing) means moving bits in the MS -> LS bit
 106 * direction.  Zeros are fed into the vacated MS positions and the
 107 * LS bits shifted off the bottom are lost.
 108 */
 109void __bitmap_shift_right(unsigned long *dst,
 110                        const unsigned long *src, int shift, int bits)
 111{
 112        int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
 113        int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
 114        unsigned long mask = (1UL << left) - 1;
 115        for (k = 0; off + k < lim; ++k) {
 116                unsigned long upper, lower;
 117
 118                /*
 119                 * If shift is not word aligned, take lower rem bits of
 120                 * word above and make them the top rem bits of result.
 121                 */
 122                if (!rem || off + k + 1 >= lim)
 123                        upper = 0;
 124                else {
 125                        upper = src[off + k + 1];
 126                        if (off + k + 1 == lim - 1 && left)
 127                                upper &= mask;
 128                }
 129                lower = src[off + k];
 130                if (left && off + k == lim - 1)
 131                        lower &= mask;
 132                dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
 133                if (left && k == lim - 1)
 134                        dst[k] &= mask;
 135        }
 136        if (off)
 137                memset(&dst[lim - off], 0, off*sizeof(unsigned long));
 138}
 139EXPORT_SYMBOL(__bitmap_shift_right);
 140
 141
 142/**
 143 * __bitmap_shift_left - logical left shift of the bits in a bitmap
 144 *   @dst : destination bitmap
 145 *   @src : source bitmap
 146 *   @shift : shift by this many bits
 147 *   @bits : bitmap size, in bits
 148 *
 149 * Shifting left (multiplying) means moving bits in the LS -> MS
 150 * direction.  Zeros are fed into the vacated LS bit positions
 151 * and those MS bits shifted off the top are lost.
 152 */
 153
 154void __bitmap_shift_left(unsigned long *dst,
 155                        const unsigned long *src, int shift, int bits)
 156{
 157        int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
 158        int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
 159        for (k = lim - off - 1; k >= 0; --k) {
 160                unsigned long upper, lower;
 161
 162                /*
 163                 * If shift is not word aligned, take upper rem bits of
 164                 * word below and make them the bottom rem bits of result.
 165                 */
 166                if (rem && k > 0)
 167                        lower = src[k - 1];
 168                else
 169                        lower = 0;
 170                upper = src[k];
 171                if (left && k == lim - 1)
 172                        upper &= (1UL << left) - 1;
 173                dst[k + off] = lower  >> (BITS_PER_LONG - rem) | upper << rem;
 174                if (left && k + off == lim - 1)
 175                        dst[k + off] &= (1UL << left) - 1;
 176        }
 177        if (off)
 178                memset(dst, 0, off*sizeof(unsigned long));
 179}
 180EXPORT_SYMBOL(__bitmap_shift_left);
 181
 182int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
 183                                const unsigned long *bitmap2, int bits)
 184{
 185        int k;
 186        int nr = BITS_TO_LONGS(bits);
 187        unsigned long result = 0;
 188
 189        for (k = 0; k < nr; k++)
 190                result |= (dst[k] = bitmap1[k] & bitmap2[k]);
 191        return result != 0;
 192}
 193EXPORT_SYMBOL(__bitmap_and);
 194
 195void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
 196                                const unsigned long *bitmap2, int bits)
 197{
 198        int k;
 199        int nr = BITS_TO_LONGS(bits);
 200
 201        for (k = 0; k < nr; k++)
 202                dst[k] = bitmap1[k] | bitmap2[k];
 203}
 204EXPORT_SYMBOL(__bitmap_or);
 205
 206void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
 207                                const unsigned long *bitmap2, int bits)
 208{
 209        int k;
 210        int nr = BITS_TO_LONGS(bits);
 211
 212        for (k = 0; k < nr; k++)
 213                dst[k] = bitmap1[k] ^ bitmap2[k];
 214}
 215EXPORT_SYMBOL(__bitmap_xor);
 216
 217int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
 218                                const unsigned long *bitmap2, int bits)
 219{
 220        int k;
 221        int nr = BITS_TO_LONGS(bits);
 222        unsigned long result = 0;
 223
 224        for (k = 0; k < nr; k++)
 225                result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
 226        return result != 0;
 227}
 228EXPORT_SYMBOL(__bitmap_andnot);
 229
 230int __bitmap_intersects(const unsigned long *bitmap1,
 231                                const unsigned long *bitmap2, int bits)
 232{
 233        int k, lim = bits/BITS_PER_LONG;
 234        for (k = 0; k < lim; ++k)
 235                if (bitmap1[k] & bitmap2[k])
 236                        return 1;
 237
 238        if (bits % BITS_PER_LONG)
 239                if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
 240                        return 1;
 241        return 0;
 242}
 243EXPORT_SYMBOL(__bitmap_intersects);
 244
 245int __bitmap_subset(const unsigned long *bitmap1,
 246                                const unsigned long *bitmap2, int bits)
 247{
 248        int k, lim = bits/BITS_PER_LONG;
 249        for (k = 0; k < lim; ++k)
 250                if (bitmap1[k] & ~bitmap2[k])
 251                        return 0;
 252
 253        if (bits % BITS_PER_LONG)
 254                if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
 255                        return 0;
 256        return 1;
 257}
 258EXPORT_SYMBOL(__bitmap_subset);
 259
 260int __bitmap_weight(const unsigned long *bitmap, int bits)
 261{
 262        int k, w = 0, lim = bits/BITS_PER_LONG;
 263
 264        for (k = 0; k < lim; k++)
 265                w += hweight_long(bitmap[k]);
 266
 267        if (bits % BITS_PER_LONG)
 268                w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
 269
 270        return w;
 271}
 272EXPORT_SYMBOL(__bitmap_weight);
 273
 274void bitmap_set(unsigned long *map, int start, int nr)
 275{
 276        unsigned long *p = map + BIT_WORD(start);
 277        const int size = start + nr;
 278        int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
 279        unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
 280
 281        while (nr - bits_to_set >= 0) {
 282                *p |= mask_to_set;
 283                nr -= bits_to_set;
 284                bits_to_set = BITS_PER_LONG;
 285                mask_to_set = ~0UL;
 286                p++;
 287        }
 288        if (nr) {
 289                mask_to_set &= BITMAP_LAST_WORD_MASK(size);
 290                *p |= mask_to_set;
 291        }
 292}
 293EXPORT_SYMBOL(bitmap_set);
 294
 295void bitmap_clear(unsigned long *map, int start, int nr)
 296{
 297        unsigned long *p = map + BIT_WORD(start);
 298        const int size = start + nr;
 299        int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
 300        unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
 301
 302        while (nr - bits_to_clear >= 0) {
 303                *p &= ~mask_to_clear;
 304                nr -= bits_to_clear;
 305                bits_to_clear = BITS_PER_LONG;
 306                mask_to_clear = ~0UL;
 307                p++;
 308        }
 309        if (nr) {
 310                mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
 311                *p &= ~mask_to_clear;
 312        }
 313}
 314EXPORT_SYMBOL(bitmap_clear);
 315
 316/*
 317 * bitmap_find_next_zero_area - find a contiguous aligned zero area
 318 * @map: The address to base the search on
 319 * @size: The bitmap size in bits
 320 * @start: The bitnumber to start searching at
 321 * @nr: The number of zeroed bits we're looking for
 322 * @align_mask: Alignment mask for zero area
 323 *
 324 * The @align_mask should be one less than a power of 2; the effect is that
 325 * the bit offset of all zero areas this function finds is multiples of that
 326 * power of 2. A @align_mask of 0 means no alignment is required.
 327 */
 328unsigned long bitmap_find_next_zero_area(unsigned long *map,
 329                                         unsigned long size,
 330                                         unsigned long start,
 331                                         unsigned int nr,
 332                                         unsigned long align_mask)
 333{
 334        unsigned long index, end, i;
 335again:
 336        index = find_next_zero_bit(map, size, start);
 337
 338        /* Align allocation */
 339        index = __ALIGN_MASK(index, align_mask);
 340
 341        end = index + nr;
 342        if (end > size)
 343                return end;
 344        i = find_next_bit(map, end, index);
 345        if (i < end) {
 346                start = i + 1;
 347                goto again;
 348        }
 349        return index;
 350}
 351EXPORT_SYMBOL(bitmap_find_next_zero_area);
 352
 353/*
 354 * Bitmap printing & parsing functions: first version by Bill Irwin,
 355 * second version by Paul Jackson, third by Joe Korty.
 356 */
 357
 358#define CHUNKSZ                         32
 359#define nbits_to_hold_value(val)        fls(val)
 360#define BASEDEC 10              /* fancier cpuset lists input in decimal */
 361
 362/**
 363 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
 364 * @buf: byte buffer into which string is placed
 365 * @buflen: reserved size of @buf, in bytes
 366 * @maskp: pointer to bitmap to convert
 367 * @nmaskbits: size of bitmap, in bits
 368 *
 369 * Exactly @nmaskbits bits are displayed.  Hex digits are grouped into
 370 * comma-separated sets of eight digits per set.
 371 */
 372int bitmap_scnprintf(char *buf, unsigned int buflen,
 373        const unsigned long *maskp, int nmaskbits)
 374{
 375        int i, word, bit, len = 0;
 376        unsigned long val;
 377        const char *sep = "";
 378        int chunksz;
 379        u32 chunkmask;
 380
 381        chunksz = nmaskbits & (CHUNKSZ - 1);
 382        if (chunksz == 0)
 383                chunksz = CHUNKSZ;
 384
 385        i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
 386        for (; i >= 0; i -= CHUNKSZ) {
 387                chunkmask = ((1ULL << chunksz) - 1);
 388                word = i / BITS_PER_LONG;
 389                bit = i % BITS_PER_LONG;
 390                val = (maskp[word] >> bit) & chunkmask;
 391                len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
 392                        (chunksz+3)/4, val);
 393                chunksz = CHUNKSZ;
 394                sep = ",";
 395        }
 396        return len;
 397}
 398EXPORT_SYMBOL(bitmap_scnprintf);
 399
 400/**
 401 * __bitmap_parse - convert an ASCII hex string into a bitmap.
 402 * @buf: pointer to buffer containing string.
 403 * @buflen: buffer size in bytes.  If string is smaller than this
 404 *    then it must be terminated with a \0.
 405 * @is_user: location of buffer, 0 indicates kernel space
 406 * @maskp: pointer to bitmap array that will contain result.
 407 * @nmaskbits: size of bitmap, in bits.
 408 *
 409 * Commas group hex digits into chunks.  Each chunk defines exactly 32
 410 * bits of the resultant bitmask.  No chunk may specify a value larger
 411 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
 412 * then leading 0-bits are prepended.  %-EINVAL is returned for illegal
 413 * characters and for grouping errors such as "1,,5", ",44", "," and "".
 414 * Leading and trailing whitespace accepted, but not embedded whitespace.
 415 */
 416int __bitmap_parse(const char *buf, unsigned int buflen,
 417                int is_user, unsigned long *maskp,
 418                int nmaskbits)
 419{
 420        int c, old_c, totaldigits, ndigits, nchunks, nbits;
 421        u32 chunk;
 422        const char __user *ubuf = buf;
 423
 424        bitmap_zero(maskp, nmaskbits);
 425
 426        nchunks = nbits = totaldigits = c = 0;
 427        do {
 428                chunk = ndigits = 0;
 429
 430                /* Get the next chunk of the bitmap */
 431                while (buflen) {
 432                        old_c = c;
 433                        if (is_user) {
 434                                if (__get_user(c, ubuf++))
 435                                        return -EFAULT;
 436                        }
 437                        else
 438                                c = *buf++;
 439                        buflen--;
 440                        if (isspace(c))
 441                                continue;
 442
 443                        /*
 444                         * If the last character was a space and the current
 445                         * character isn't '\0', we've got embedded whitespace.
 446                         * This is a no-no, so throw an error.
 447                         */
 448                        if (totaldigits && c && isspace(old_c))
 449                                return -EINVAL;
 450
 451                        /* A '\0' or a ',' signal the end of the chunk */
 452                        if (c == '\0' || c == ',')
 453                                break;
 454
 455                        if (!isxdigit(c))
 456                                return -EINVAL;
 457
 458                        /*
 459                         * Make sure there are at least 4 free bits in 'chunk'.
 460                         * If not, this hexdigit will overflow 'chunk', so
 461                         * throw an error.
 462                         */
 463                        if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
 464                                return -EOVERFLOW;
 465
 466                        chunk = (chunk << 4) | hex_to_bin(c);
 467                        ndigits++; totaldigits++;
 468                }
 469                if (ndigits == 0)
 470                        return -EINVAL;
 471                if (nchunks == 0 && chunk == 0)
 472                        continue;
 473
 474                __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
 475                *maskp |= chunk;
 476                nchunks++;
 477                nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
 478                if (nbits > nmaskbits)
 479                        return -EOVERFLOW;
 480        } while (buflen && c == ',');
 481
 482        return 0;
 483}
 484EXPORT_SYMBOL(__bitmap_parse);
 485
 486/**
 487 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
 488 *
 489 * @ubuf: pointer to user buffer containing string.
 490 * @ulen: buffer size in bytes.  If string is smaller than this
 491 *    then it must be terminated with a \0.
 492 * @maskp: pointer to bitmap array that will contain result.
 493 * @nmaskbits: size of bitmap, in bits.
 494 *
 495 * Wrapper for __bitmap_parse(), providing it with user buffer.
 496 *
 497 * We cannot have this as an inline function in bitmap.h because it needs
 498 * linux/uaccess.h to get the access_ok() declaration and this causes
 499 * cyclic dependencies.
 500 */
 501int bitmap_parse_user(const char __user *ubuf,
 502                        unsigned int ulen, unsigned long *maskp,
 503                        int nmaskbits)
 504{
 505        if (!access_ok(VERIFY_READ, ubuf, ulen))
 506                return -EFAULT;
 507        return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits);
 508}
 509EXPORT_SYMBOL(bitmap_parse_user);
 510
 511/*
 512 * bscnl_emit(buf, buflen, rbot, rtop, bp)
 513 *
 514 * Helper routine for bitmap_scnlistprintf().  Write decimal number
 515 * or range to buf, suppressing output past buf+buflen, with optional
 516 * comma-prefix.  Return len of what would be written to buf, if it
 517 * all fit.
 518 */
 519static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
 520{
 521        if (len > 0)
 522                len += scnprintf(buf + len, buflen - len, ",");
 523        if (rbot == rtop)
 524                len += scnprintf(buf + len, buflen - len, "%d", rbot);
 525        else
 526                len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
 527        return len;
 528}
 529
 530/**
 531 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
 532 * @buf: byte buffer into which string is placed
 533 * @buflen: reserved size of @buf, in bytes
 534 * @maskp: pointer to bitmap to convert
 535 * @nmaskbits: size of bitmap, in bits
 536 *
 537 * Output format is a comma-separated list of decimal numbers and
 538 * ranges.  Consecutively set bits are shown as two hyphen-separated
 539 * decimal numbers, the smallest and largest bit numbers set in
 540 * the range.  Output format is compatible with the format
 541 * accepted as input by bitmap_parselist().
 542 *
 543 * The return value is the number of characters which would be
 544 * generated for the given input, excluding the trailing '\0', as
 545 * per ISO C99.
 546 */
 547int bitmap_scnlistprintf(char *buf, unsigned int buflen,
 548        const unsigned long *maskp, int nmaskbits)
 549{
 550        int len = 0;
 551        /* current bit is 'cur', most recently seen range is [rbot, rtop] */
 552        int cur, rbot, rtop;
 553
 554        if (buflen == 0)
 555                return 0;
 556        buf[0] = 0;
 557
 558        rbot = cur = find_first_bit(maskp, nmaskbits);
 559        while (cur < nmaskbits) {
 560                rtop = cur;
 561                cur = find_next_bit(maskp, nmaskbits, cur+1);
 562                if (cur >= nmaskbits || cur > rtop + 1) {
 563                        len = bscnl_emit(buf, buflen, rbot, rtop, len);
 564                        rbot = cur;
 565                }
 566        }
 567        return len;
 568}
 569EXPORT_SYMBOL(bitmap_scnlistprintf);
 570
 571/**
 572 * __bitmap_parselist - convert list format ASCII string to bitmap
 573 * @buf: read nul-terminated user string from this buffer
 574 * @buflen: buffer size in bytes.  If string is smaller than this
 575 *    then it must be terminated with a \0.
 576 * @is_user: location of buffer, 0 indicates kernel space
 577 * @maskp: write resulting mask here
 578 * @nmaskbits: number of bits in mask to be written
 579 *
 580 * Input format is a comma-separated list of decimal numbers and
 581 * ranges.  Consecutively set bits are shown as two hyphen-separated
 582 * decimal numbers, the smallest and largest bit numbers set in
 583 * the range.
 584 *
 585 * Returns 0 on success, -errno on invalid input strings.
 586 * Error values:
 587 *    %-EINVAL: second number in range smaller than first
 588 *    %-EINVAL: invalid character in string
 589 *    %-ERANGE: bit number specified too large for mask
 590 */
 591static int __bitmap_parselist(const char *buf, unsigned int buflen,
 592                int is_user, unsigned long *maskp,
 593                int nmaskbits)
 594{
 595        unsigned a, b;
 596        int c, old_c, totaldigits;
 597        const char __user *ubuf = buf;
 598        int exp_digit, in_range;
 599
 600        totaldigits = c = 0;
 601        bitmap_zero(maskp, nmaskbits);
 602        do {
 603                exp_digit = 1;
 604                in_range = 0;
 605                a = b = 0;
 606
 607                /* Get the next cpu# or a range of cpu#'s */
 608                while (buflen) {
 609                        old_c = c;
 610                        if (is_user) {
 611                                if (__get_user(c, ubuf++))
 612                                        return -EFAULT;
 613                        } else
 614                                c = *buf++;
 615                        buflen--;
 616                        if (isspace(c))
 617                                continue;
 618
 619                        /*
 620                         * If the last character was a space and the current
 621                         * character isn't '\0', we've got embedded whitespace.
 622                         * This is a no-no, so throw an error.
 623                         */
 624                        if (totaldigits && c && isspace(old_c))
 625                                return -EINVAL;
 626
 627                        /* A '\0' or a ',' signal the end of a cpu# or range */
 628                        if (c == '\0' || c == ',')
 629                                break;
 630
 631                        if (c == '-') {
 632                                if (exp_digit || in_range)
 633                                        return -EINVAL;
 634                                b = 0;
 635                                in_range = 1;
 636                                exp_digit = 1;
 637                                continue;
 638                        }
 639
 640                        if (!isdigit(c))
 641                                return -EINVAL;
 642
 643                        b = b * 10 + (c - '0');
 644                        if (!in_range)
 645                                a = b;
 646                        exp_digit = 0;
 647                        totaldigits++;
 648                }
 649                if (!(a <= b))
 650                        return -EINVAL;
 651                if (b >= nmaskbits)
 652                        return -ERANGE;
 653                while (a <= b) {
 654                        set_bit(a, maskp);
 655                        a++;
 656                }
 657        } while (buflen && c == ',');
 658        return 0;
 659}
 660
 661int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
 662{
 663        char *nl  = strchr(bp, '\n');
 664        int len;
 665
 666        if (nl)
 667                len = nl - bp;
 668        else
 669                len = strlen(bp);
 670
 671        return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
 672}
 673EXPORT_SYMBOL(bitmap_parselist);
 674
 675
 676/**
 677 * bitmap_parselist_user()
 678 *
 679 * @ubuf: pointer to user buffer containing string.
 680 * @ulen: buffer size in bytes.  If string is smaller than this
 681 *    then it must be terminated with a \0.
 682 * @maskp: pointer to bitmap array that will contain result.
 683 * @nmaskbits: size of bitmap, in bits.
 684 *
 685 * Wrapper for bitmap_parselist(), providing it with user buffer.
 686 *
 687 * We cannot have this as an inline function in bitmap.h because it needs
 688 * linux/uaccess.h to get the access_ok() declaration and this causes
 689 * cyclic dependencies.
 690 */
 691int bitmap_parselist_user(const char __user *ubuf,
 692                        unsigned int ulen, unsigned long *maskp,
 693                        int nmaskbits)
 694{
 695        if (!access_ok(VERIFY_READ, ubuf, ulen))
 696                return -EFAULT;
 697        return __bitmap_parselist((const char *)ubuf,
 698                                        ulen, 1, maskp, nmaskbits);
 699}
 700EXPORT_SYMBOL(bitmap_parselist_user);
 701
 702
 703/**
 704 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
 705 *      @buf: pointer to a bitmap
 706 *      @pos: a bit position in @buf (0 <= @pos < @bits)
 707 *      @bits: number of valid bit positions in @buf
 708 *
 709 * Map the bit at position @pos in @buf (of length @bits) to the
 710 * ordinal of which set bit it is.  If it is not set or if @pos
 711 * is not a valid bit position, map to -1.
 712 *
 713 * If for example, just bits 4 through 7 are set in @buf, then @pos
 714 * values 4 through 7 will get mapped to 0 through 3, respectively,
 715 * and other @pos values will get mapped to 0.  When @pos value 7
 716 * gets mapped to (returns) @ord value 3 in this example, that means
 717 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
 718 *
 719 * The bit positions 0 through @bits are valid positions in @buf.
 720 */
 721static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
 722{
 723        int i, ord;
 724
 725        if (pos < 0 || pos >= bits || !test_bit(pos, buf))
 726                return -1;
 727
 728        i = find_first_bit(buf, bits);
 729        ord = 0;
 730        while (i < pos) {
 731                i = find_next_bit(buf, bits, i + 1);
 732                ord++;
 733        }
 734        BUG_ON(i != pos);
 735
 736        return ord;
 737}
 738
 739/**
 740 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
 741 *      @buf: pointer to bitmap
 742 *      @ord: ordinal bit position (n-th set bit, n >= 0)
 743 *      @bits: number of valid bit positions in @buf
 744 *
 745 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
 746 * Value of @ord should be in range 0 <= @ord < weight(buf), else
 747 * results are undefined.
 748 *
 749 * If for example, just bits 4 through 7 are set in @buf, then @ord
 750 * values 0 through 3 will get mapped to 4 through 7, respectively,
 751 * and all other @ord values return undefined values.  When @ord value 3
 752 * gets mapped to (returns) @pos value 7 in this example, that means
 753 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
 754 *
 755 * The bit positions 0 through @bits are valid positions in @buf.
 756 */
 757int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
 758{
 759        int pos = 0;
 760
 761        if (ord >= 0 && ord < bits) {
 762                int i;
 763
 764                for (i = find_first_bit(buf, bits);
 765                     i < bits && ord > 0;
 766                     i = find_next_bit(buf, bits, i + 1))
 767                        ord--;
 768                if (i < bits && ord == 0)
 769                        pos = i;
 770        }
 771
 772        return pos;
 773}
 774
 775/**
 776 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
 777 *      @dst: remapped result
 778 *      @src: subset to be remapped
 779 *      @old: defines domain of map
 780 *      @new: defines range of map
 781 *      @bits: number of bits in each of these bitmaps
 782 *
 783 * Let @old and @new define a mapping of bit positions, such that
 784 * whatever position is held by the n-th set bit in @old is mapped
 785 * to the n-th set bit in @new.  In the more general case, allowing
 786 * for the possibility that the weight 'w' of @new is less than the
 787 * weight of @old, map the position of the n-th set bit in @old to
 788 * the position of the m-th set bit in @new, where m == n % w.
 789 *
 790 * If either of the @old and @new bitmaps are empty, or if @src and
 791 * @dst point to the same location, then this routine copies @src
 792 * to @dst.
 793 *
 794 * The positions of unset bits in @old are mapped to themselves
 795 * (the identify map).
 796 *
 797 * Apply the above specified mapping to @src, placing the result in
 798 * @dst, clearing any bits previously set in @dst.
 799 *
 800 * For example, lets say that @old has bits 4 through 7 set, and
 801 * @new has bits 12 through 15 set.  This defines the mapping of bit
 802 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
 803 * bit positions unchanged.  So if say @src comes into this routine
 804 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
 805 * 13 and 15 set.
 806 */
 807void bitmap_remap(unsigned long *dst, const unsigned long *src,
 808                const unsigned long *old, const unsigned long *new,
 809                int bits)
 810{
 811        int oldbit, w;
 812
 813        if (dst == src)         /* following doesn't handle inplace remaps */
 814                return;
 815        bitmap_zero(dst, bits);
 816
 817        w = bitmap_weight(new, bits);
 818        for_each_set_bit(oldbit, src, bits) {
 819                int n = bitmap_pos_to_ord(old, oldbit, bits);
 820
 821                if (n < 0 || w == 0)
 822                        set_bit(oldbit, dst);   /* identity map */
 823                else
 824                        set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
 825        }
 826}
 827EXPORT_SYMBOL(bitmap_remap);
 828
 829/**
 830 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
 831 *      @oldbit: bit position to be mapped
 832 *      @old: defines domain of map
 833 *      @new: defines range of map
 834 *      @bits: number of bits in each of these bitmaps
 835 *
 836 * Let @old and @new define a mapping of bit positions, such that
 837 * whatever position is held by the n-th set bit in @old is mapped
 838 * to the n-th set bit in @new.  In the more general case, allowing
 839 * for the possibility that the weight 'w' of @new is less than the
 840 * weight of @old, map the position of the n-th set bit in @old to
 841 * the position of the m-th set bit in @new, where m == n % w.
 842 *
 843 * The positions of unset bits in @old are mapped to themselves
 844 * (the identify map).
 845 *
 846 * Apply the above specified mapping to bit position @oldbit, returning
 847 * the new bit position.
 848 *
 849 * For example, lets say that @old has bits 4 through 7 set, and
 850 * @new has bits 12 through 15 set.  This defines the mapping of bit
 851 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
 852 * bit positions unchanged.  So if say @oldbit is 5, then this routine
 853 * returns 13.
 854 */
 855int bitmap_bitremap(int oldbit, const unsigned long *old,
 856                                const unsigned long *new, int bits)
 857{
 858        int w = bitmap_weight(new, bits);
 859        int n = bitmap_pos_to_ord(old, oldbit, bits);
 860        if (n < 0 || w == 0)
 861                return oldbit;
 862        else
 863                return bitmap_ord_to_pos(new, n % w, bits);
 864}
 865EXPORT_SYMBOL(bitmap_bitremap);
 866
 867/**
 868 * bitmap_onto - translate one bitmap relative to another
 869 *      @dst: resulting translated bitmap
 870 *      @orig: original untranslated bitmap
 871 *      @relmap: bitmap relative to which translated
 872 *      @bits: number of bits in each of these bitmaps
 873 *
 874 * Set the n-th bit of @dst iff there exists some m such that the
 875 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
 876 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
 877 * (If you understood the previous sentence the first time your
 878 * read it, you're overqualified for your current job.)
 879 *
 880 * In other words, @orig is mapped onto (surjectively) @dst,
 881 * using the the map { <n, m> | the n-th bit of @relmap is the
 882 * m-th set bit of @relmap }.
 883 *
 884 * Any set bits in @orig above bit number W, where W is the
 885 * weight of (number of set bits in) @relmap are mapped nowhere.
 886 * In particular, if for all bits m set in @orig, m >= W, then
 887 * @dst will end up empty.  In situations where the possibility
 888 * of such an empty result is not desired, one way to avoid it is
 889 * to use the bitmap_fold() operator, below, to first fold the
 890 * @orig bitmap over itself so that all its set bits x are in the
 891 * range 0 <= x < W.  The bitmap_fold() operator does this by
 892 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
 893 *
 894 * Example [1] for bitmap_onto():
 895 *  Let's say @relmap has bits 30-39 set, and @orig has bits
 896 *  1, 3, 5, 7, 9 and 11 set.  Then on return from this routine,
 897 *  @dst will have bits 31, 33, 35, 37 and 39 set.
 898 *
 899 *  When bit 0 is set in @orig, it means turn on the bit in
 900 *  @dst corresponding to whatever is the first bit (if any)
 901 *  that is turned on in @relmap.  Since bit 0 was off in the
 902 *  above example, we leave off that bit (bit 30) in @dst.
 903 *
 904 *  When bit 1 is set in @orig (as in the above example), it
 905 *  means turn on the bit in @dst corresponding to whatever
 906 *  is the second bit that is turned on in @relmap.  The second
 907 *  bit in @relmap that was turned on in the above example was
 908 *  bit 31, so we turned on bit 31 in @dst.
 909 *
 910 *  Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
 911 *  because they were the 4th, 6th, 8th and 10th set bits
 912 *  set in @relmap, and the 4th, 6th, 8th and 10th bits of
 913 *  @orig (i.e. bits 3, 5, 7 and 9) were also set.
 914 *
 915 *  When bit 11 is set in @orig, it means turn on the bit in
 916 *  @dst corresponding to whatever is the twelfth bit that is
 917 *  turned on in @relmap.  In the above example, there were
 918 *  only ten bits turned on in @relmap (30..39), so that bit
 919 *  11 was set in @orig had no affect on @dst.
 920 *
 921 * Example [2] for bitmap_fold() + bitmap_onto():
 922 *  Let's say @relmap has these ten bits set:
 923 *              40 41 42 43 45 48 53 61 74 95
 924 *  (for the curious, that's 40 plus the first ten terms of the
 925 *  Fibonacci sequence.)
 926 *
 927 *  Further lets say we use the following code, invoking
 928 *  bitmap_fold() then bitmap_onto, as suggested above to
 929 *  avoid the possitility of an empty @dst result:
 930 *
 931 *      unsigned long *tmp;     // a temporary bitmap's bits
 932 *
 933 *      bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
 934 *      bitmap_onto(dst, tmp, relmap, bits);
 935 *
 936 *  Then this table shows what various values of @dst would be, for
 937 *  various @orig's.  I list the zero-based positions of each set bit.
 938 *  The tmp column shows the intermediate result, as computed by
 939 *  using bitmap_fold() to fold the @orig bitmap modulo ten
 940 *  (the weight of @relmap).
 941 *
 942 *      @orig           tmp            @dst
 943 *      0                0             40
 944 *      1                1             41
 945 *      9                9             95
 946 *      10               0             40 (*)
 947 *      1 3 5 7          1 3 5 7       41 43 48 61
 948 *      0 1 2 3 4        0 1 2 3 4     40 41 42 43 45
 949 *      0 9 18 27        0 9 8 7       40 61 74 95
 950 *      0 10 20 30       0             40
 951 *      0 11 22 33       0 1 2 3       40 41 42 43
 952 *      0 12 24 36       0 2 4 6       40 42 45 53
 953 *      78 102 211       1 2 8         41 42 74 (*)
 954 *
 955 * (*) For these marked lines, if we hadn't first done bitmap_fold()
 956 *     into tmp, then the @dst result would have been empty.
 957 *
 958 * If either of @orig or @relmap is empty (no set bits), then @dst
 959 * will be returned empty.
 960 *
 961 * If (as explained above) the only set bits in @orig are in positions
 962 * m where m >= W, (where W is the weight of @relmap) then @dst will
 963 * once again be returned empty.
 964 *
 965 * All bits in @dst not set by the above rule are cleared.
 966 */
 967void bitmap_onto(unsigned long *dst, const unsigned long *orig,
 968                        const unsigned long *relmap, int bits)
 969{
 970        int n, m;               /* same meaning as in above comment */
 971
 972        if (dst == orig)        /* following doesn't handle inplace mappings */
 973                return;
 974        bitmap_zero(dst, bits);
 975
 976        /*
 977         * The following code is a more efficient, but less
 978         * obvious, equivalent to the loop:
 979         *      for (m = 0; m < bitmap_weight(relmap, bits); m++) {
 980         *              n = bitmap_ord_to_pos(orig, m, bits);
 981         *              if (test_bit(m, orig))
 982         *                      set_bit(n, dst);
 983         *      }
 984         */
 985
 986        m = 0;
 987        for_each_set_bit(n, relmap, bits) {
 988                /* m == bitmap_pos_to_ord(relmap, n, bits) */
 989                if (test_bit(m, orig))
 990                        set_bit(n, dst);
 991                m++;
 992        }
 993}
 994EXPORT_SYMBOL(bitmap_onto);
 995
 996/**
 997 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
 998 *      @dst: resulting smaller bitmap
 999 *      @orig: original larger bitmap
1000 *      @sz: specified size
1001 *      @bits: number of bits in each of these bitmaps
1002 *
1003 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1004 * Clear all other bits in @dst.  See further the comment and
1005 * Example [2] for bitmap_onto() for why and how to use this.
1006 */
1007void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1008                        int sz, int bits)
1009{
1010        int oldbit;
1011
1012        if (dst == orig)        /* following doesn't handle inplace mappings */
1013                return;
1014        bitmap_zero(dst, bits);
1015
1016        for_each_set_bit(oldbit, orig, bits)
1017                set_bit(oldbit % sz, dst);
1018}
1019EXPORT_SYMBOL(bitmap_fold);
1020
1021/*
1022 * Common code for bitmap_*_region() routines.
1023 *      bitmap: array of unsigned longs corresponding to the bitmap
1024 *      pos: the beginning of the region
1025 *      order: region size (log base 2 of number of bits)
1026 *      reg_op: operation(s) to perform on that region of bitmap
1027 *
1028 * Can set, verify and/or release a region of bits in a bitmap,
1029 * depending on which combination of REG_OP_* flag bits is set.
1030 *
1031 * A region of a bitmap is a sequence of bits in the bitmap, of
1032 * some size '1 << order' (a power of two), aligned to that same
1033 * '1 << order' power of two.
1034 *
1035 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1036 * Returns 0 in all other cases and reg_ops.
1037 */
1038
1039enum {
1040        REG_OP_ISFREE,          /* true if region is all zero bits */
1041        REG_OP_ALLOC,           /* set all bits in region */
1042        REG_OP_RELEASE,         /* clear all bits in region */
1043};
1044
1045static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op)
1046{
1047        int nbits_reg;          /* number of bits in region */
1048        int index;              /* index first long of region in bitmap */
1049        int offset;             /* bit offset region in bitmap[index] */
1050        int nlongs_reg;         /* num longs spanned by region in bitmap */
1051        int nbitsinlong;        /* num bits of region in each spanned long */
1052        unsigned long mask;     /* bitmask for one long of region */
1053        int i;                  /* scans bitmap by longs */
1054        int ret = 0;            /* return value */
1055
1056        /*
1057         * Either nlongs_reg == 1 (for small orders that fit in one long)
1058         * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1059         */
1060        nbits_reg = 1 << order;
1061        index = pos / BITS_PER_LONG;
1062        offset = pos - (index * BITS_PER_LONG);
1063        nlongs_reg = BITS_TO_LONGS(nbits_reg);
1064        nbitsinlong = min(nbits_reg,  BITS_PER_LONG);
1065
1066        /*
1067         * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1068         * overflows if nbitsinlong == BITS_PER_LONG.
1069         */
1070        mask = (1UL << (nbitsinlong - 1));
1071        mask += mask - 1;
1072        mask <<= offset;
1073
1074        switch (reg_op) {
1075        case REG_OP_ISFREE:
1076                for (i = 0; i < nlongs_reg; i++) {
1077                        if (bitmap[index + i] & mask)
1078                                goto done;
1079                }
1080                ret = 1;        /* all bits in region free (zero) */
1081                break;
1082
1083        case REG_OP_ALLOC:
1084                for (i = 0; i < nlongs_reg; i++)
1085                        bitmap[index + i] |= mask;
1086                break;
1087
1088        case REG_OP_RELEASE:
1089                for (i = 0; i < nlongs_reg; i++)
1090                        bitmap[index + i] &= ~mask;
1091                break;
1092        }
1093done:
1094        return ret;
1095}
1096
1097/**
1098 * bitmap_find_free_region - find a contiguous aligned mem region
1099 *      @bitmap: array of unsigned longs corresponding to the bitmap
1100 *      @bits: number of bits in the bitmap
1101 *      @order: region size (log base 2 of number of bits) to find
1102 *
1103 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1104 * allocate them (set them to one).  Only consider regions of length
1105 * a power (@order) of two, aligned to that power of two, which
1106 * makes the search algorithm much faster.
1107 *
1108 * Return the bit offset in bitmap of the allocated region,
1109 * or -errno on failure.
1110 */
1111int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
1112{
1113        int pos, end;           /* scans bitmap by regions of size order */
1114
1115        for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) {
1116                if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1117                        continue;
1118                __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1119                return pos;
1120        }
1121        return -ENOMEM;
1122}
1123EXPORT_SYMBOL(bitmap_find_free_region);
1124
1125/**
1126 * bitmap_release_region - release allocated bitmap region
1127 *      @bitmap: array of unsigned longs corresponding to the bitmap
1128 *      @pos: beginning of bit region to release
1129 *      @order: region size (log base 2 of number of bits) to release
1130 *
1131 * This is the complement to __bitmap_find_free_region() and releases
1132 * the found region (by clearing it in the bitmap).
1133 *
1134 * No return value.
1135 */
1136void bitmap_release_region(unsigned long *bitmap, int pos, int order)
1137{
1138        __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1139}
1140EXPORT_SYMBOL(bitmap_release_region);
1141
1142/**
1143 * bitmap_allocate_region - allocate bitmap region
1144 *      @bitmap: array of unsigned longs corresponding to the bitmap
1145 *      @pos: beginning of bit region to allocate
1146 *      @order: region size (log base 2 of number of bits) to allocate
1147 *
1148 * Allocate (set bits in) a specified region of a bitmap.
1149 *
1150 * Return 0 on success, or %-EBUSY if specified region wasn't
1151 * free (not all bits were zero).
1152 */
1153int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
1154{
1155        if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1156                return -EBUSY;
1157        __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1158        return 0;
1159}
1160EXPORT_SYMBOL(bitmap_allocate_region);
1161
1162/**
1163 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1164 * @dst:   destination buffer
1165 * @src:   bitmap to copy
1166 * @nbits: number of bits in the bitmap
1167 *
1168 * Require nbits % BITS_PER_LONG == 0.
1169 */
1170void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1171{
1172        unsigned long *d = dst;
1173        int i;
1174
1175        for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1176                if (BITS_PER_LONG == 64)
1177                        d[i] = cpu_to_le64(src[i]);
1178                else
1179                        d[i] = cpu_to_le32(src[i]);
1180        }
1181}
1182EXPORT_SYMBOL(bitmap_copy_le);
1183
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