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/export.h>
   9#include <linux/thread_info.h>
  10#include <linux/ctype.h>
  11#include <linux/errno.h>
  12#include <linux/bitmap.h>
  13#include <linux/bitops.h>
  14#include <linux/bug.h>
  15#include <asm/uaccess.h>
  16
  17/*
  18 * bitmaps provide an array of bits, implemented using an an
  19 * array of unsigned longs.  The number of valid bits in a
  20 * given bitmap does _not_ need to be an exact multiple of
  21 * BITS_PER_LONG.
  22 *
  23 * The possible unused bits in the last, partially used word
  24 * of a bitmap are 'don't care'.  The implementation makes
  25 * no particular effort to keep them zero.  It ensures that
  26 * their value will not affect the results of any operation.
  27 * The bitmap operations that return Boolean (bitmap_empty,
  28 * for example) or scalar (bitmap_weight, for example) results
  29 * carefully filter out these unused bits from impacting their
  30 * results.
  31 *
  32 * These operations actually hold to a slightly stronger rule:
  33 * if you don't input any bitmaps to these ops that have some
  34 * unused bits set, then they won't output any set unused bits
  35 * in output bitmaps.
  36 *
  37 * The byte ordering of bitmaps is more natural on little
  38 * endian architectures.  See the big-endian headers
  39 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
  40 * for the best explanations of this ordering.
  41 */
  42
  43int __bitmap_empty(const unsigned long *bitmap, int bits)
  44{
  45        int k, lim = bits/BITS_PER_LONG;
  46        for (k = 0; k < lim; ++k)
  47                if (bitmap[k])
  48                        return 0;
  49
  50        if (bits % BITS_PER_LONG)
  51                if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
  52                        return 0;
  53
  54        return 1;
  55}
  56EXPORT_SYMBOL(__bitmap_empty);
  57
  58int __bitmap_full(const unsigned long *bitmap, int bits)
  59{
  60        int k, lim = bits/BITS_PER_LONG;
  61        for (k = 0; k < lim; ++k)
  62                if (~bitmap[k])
  63                        return 0;
  64
  65        if (bits % BITS_PER_LONG)
  66                if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
  67                        return 0;
  68
  69        return 1;
  70}
  71EXPORT_SYMBOL(__bitmap_full);
  72
  73int __bitmap_equal(const unsigned long *bitmap1,
  74                const unsigned long *bitmap2, int bits)
  75{
  76        int k, lim = bits/BITS_PER_LONG;
  77        for (k = 0; k < lim; ++k)
  78                if (bitmap1[k] != bitmap2[k])
  79                        return 0;
  80
  81        if (bits % BITS_PER_LONG)
  82                if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
  83                        return 0;
  84
  85        return 1;
  86}
  87EXPORT_SYMBOL(__bitmap_equal);
  88
  89void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
  90{
  91        int k, lim = bits/BITS_PER_LONG;
  92        for (k = 0; k < lim; ++k)
  93                dst[k] = ~src[k];
  94
  95        if (bits % BITS_PER_LONG)
  96                dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
  97}
  98EXPORT_SYMBOL(__bitmap_complement);
  99
 100/**
 101 * __bitmap_shift_right - logical right shift of the bits in a bitmap
 102 *   @dst : destination bitmap
 103 *   @src : source bitmap
 104 *   @shift : shift by this many bits
 105 *   @bits : bitmap size, in bits
 106 *
 107 * Shifting right (dividing) means moving bits in the MS -> LS bit
 108 * direction.  Zeros are fed into the vacated MS positions and the
 109 * LS bits shifted off the bottom are lost.
 110 */
 111void __bitmap_shift_right(unsigned long *dst,
 112                        const unsigned long *src, int shift, int bits)
 113{
 114        int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
 115        int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
 116        unsigned long mask = (1UL << left) - 1;
 117        for (k = 0; off + k < lim; ++k) {
 118                unsigned long upper, lower;
 119
 120                /*
 121                 * If shift is not word aligned, take lower rem bits of
 122                 * word above and make them the top rem bits of result.
 123                 */
 124                if (!rem || off + k + 1 >= lim)
 125                        upper = 0;
 126                else {
 127                        upper = src[off + k + 1];
 128                        if (off + k + 1 == lim - 1 && left)
 129                                upper &= mask;
 130                }
 131                lower = src[off + k];
 132                if (left && off + k == lim - 1)
 133                        lower &= mask;
 134                dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
 135                if (left && k == lim - 1)
 136                        dst[k] &= mask;
 137        }
 138        if (off)
 139                memset(&dst[lim - off], 0, off*sizeof(unsigned long));
 140}
 141EXPORT_SYMBOL(__bitmap_shift_right);
 142
 143
 144/**
 145 * __bitmap_shift_left - logical left shift of the bits in a bitmap
 146 *   @dst : destination bitmap
 147 *   @src : source bitmap
 148 *   @shift : shift by this many bits
 149 *   @bits : bitmap size, in bits
 150 *
 151 * Shifting left (multiplying) means moving bits in the LS -> MS
 152 * direction.  Zeros are fed into the vacated LS bit positions
 153 * and those MS bits shifted off the top are lost.
 154 */
 155
 156void __bitmap_shift_left(unsigned long *dst,
 157                        const unsigned long *src, int shift, int bits)
 158{
 159        int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
 160        int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
 161        for (k = lim - off - 1; k >= 0; --k) {
 162                unsigned long upper, lower;
 163
 164                /*
 165                 * If shift is not word aligned, take upper rem bits of
 166                 * word below and make them the bottom rem bits of result.
 167                 */
 168                if (rem && k > 0)
 169                        lower = src[k - 1];
 170                else
 171                        lower = 0;
 172                upper = src[k];
 173                if (left && k == lim - 1)
 174                        upper &= (1UL << left) - 1;
 175                dst[k + off] = lower  >> (BITS_PER_LONG - rem) | upper << rem;
 176                if (left && k + off == lim - 1)
 177                        dst[k + off] &= (1UL << left) - 1;
 178        }
 179        if (off)
 180                memset(dst, 0, off*sizeof(unsigned long));
 181}
 182EXPORT_SYMBOL(__bitmap_shift_left);
 183
 184int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
 185                                const unsigned long *bitmap2, int bits)
 186{
 187        int k;
 188        int nr = BITS_TO_LONGS(bits);
 189        unsigned long result = 0;
 190
 191        for (k = 0; k < nr; k++)
 192                result |= (dst[k] = bitmap1[k] & bitmap2[k]);
 193        return result != 0;
 194}
 195EXPORT_SYMBOL(__bitmap_and);
 196
 197void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
 198                                const unsigned long *bitmap2, int bits)
 199{
 200        int k;
 201        int nr = BITS_TO_LONGS(bits);
 202
 203        for (k = 0; k < nr; k++)
 204                dst[k] = bitmap1[k] | bitmap2[k];
 205}
 206EXPORT_SYMBOL(__bitmap_or);
 207
 208void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
 209                                const unsigned long *bitmap2, int bits)
 210{
 211        int k;
 212        int nr = BITS_TO_LONGS(bits);
 213
 214        for (k = 0; k < nr; k++)
 215                dst[k] = bitmap1[k] ^ bitmap2[k];
 216}
 217EXPORT_SYMBOL(__bitmap_xor);
 218
 219int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
 220                                const unsigned long *bitmap2, int bits)
 221{
 222        int k;
 223        int nr = BITS_TO_LONGS(bits);
 224        unsigned long result = 0;
 225
 226        for (k = 0; k < nr; k++)
 227                result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
 228        return result != 0;
 229}
 230EXPORT_SYMBOL(__bitmap_andnot);
 231
 232int __bitmap_intersects(const unsigned long *bitmap1,
 233                                const unsigned long *bitmap2, int bits)
 234{
 235        int k, lim = bits/BITS_PER_LONG;
 236        for (k = 0; k < lim; ++k)
 237                if (bitmap1[k] & bitmap2[k])
 238                        return 1;
 239
 240        if (bits % BITS_PER_LONG)
 241                if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
 242                        return 1;
 243        return 0;
 244}
 245EXPORT_SYMBOL(__bitmap_intersects);
 246
 247int __bitmap_subset(const unsigned long *bitmap1,
 248                                const unsigned long *bitmap2, int bits)
 249{
 250        int k, lim = bits/BITS_PER_LONG;
 251        for (k = 0; k < lim; ++k)
 252                if (bitmap1[k] & ~bitmap2[k])
 253                        return 0;
 254
 255        if (bits % BITS_PER_LONG)
 256                if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
 257                        return 0;
 258        return 1;
 259}
 260EXPORT_SYMBOL(__bitmap_subset);
 261
 262int __bitmap_weight(const unsigned long *bitmap, int bits)
 263{
 264        int k, w = 0, lim = bits/BITS_PER_LONG;
 265
 266        for (k = 0; k < lim; k++)
 267                w += hweight_long(bitmap[k]);
 268
 269        if (bits % BITS_PER_LONG)
 270                w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
 271
 272        return w;
 273}
 274EXPORT_SYMBOL(__bitmap_weight);
 275
 276void bitmap_set(unsigned long *map, int start, int nr)
 277{
 278        unsigned long *p = map + BIT_WORD(start);
 279        const int size = start + nr;
 280        int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
 281        unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
 282
 283        while (nr - bits_to_set >= 0) {
 284                *p |= mask_to_set;
 285                nr -= bits_to_set;
 286                bits_to_set = BITS_PER_LONG;
 287                mask_to_set = ~0UL;
 288                p++;
 289        }
 290        if (nr) {
 291                mask_to_set &= BITMAP_LAST_WORD_MASK(size);
 292                *p |= mask_to_set;
 293        }
 294}
 295EXPORT_SYMBOL(bitmap_set);
 296
 297void bitmap_clear(unsigned long *map, int start, int nr)
 298{
 299        unsigned long *p = map + BIT_WORD(start);
 300        const int size = start + nr;
 301        int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
 302        unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
 303
 304        while (nr - bits_to_clear >= 0) {
 305                *p &= ~mask_to_clear;
 306                nr -= bits_to_clear;
 307                bits_to_clear = BITS_PER_LONG;
 308                mask_to_clear = ~0UL;
 309                p++;
 310        }
 311        if (nr) {
 312                mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
 313                *p &= ~mask_to_clear;
 314        }
 315}
 316EXPORT_SYMBOL(bitmap_clear);
 317
 318/*
 319 * bitmap_find_next_zero_area - find a contiguous aligned zero area
 320 * @map: The address to base the search on
 321 * @size: The bitmap size in bits
 322 * @start: The bitnumber to start searching at
 323 * @nr: The number of zeroed bits we're looking for
 324 * @align_mask: Alignment mask for zero area
 325 *
 326 * The @align_mask should be one less than a power of 2; the effect is that
 327 * the bit offset of all zero areas this function finds is multiples of that
 328 * power of 2. A @align_mask of 0 means no alignment is required.
 329 */
 330unsigned long bitmap_find_next_zero_area(unsigned long *map,
 331                                         unsigned long size,
 332                                         unsigned long start,
 333                                         unsigned int nr,
 334                                         unsigned long align_mask)
 335{
 336        unsigned long index, end, i;
 337again:
 338        index = find_next_zero_bit(map, size, start);
 339
 340        /* Align allocation */
 341        index = __ALIGN_MASK(index, align_mask);
 342
 343        end = index + nr;
 344        if (end > size)
 345                return end;
 346        i = find_next_bit(map, end, index);
 347        if (i < end) {
 348                start = i + 1;
 349                goto again;
 350        }
 351        return index;
 352}
 353EXPORT_SYMBOL(bitmap_find_next_zero_area);
 354
 355/*
 356 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
 357 * second version by Paul Jackson, third by Joe Korty.
 358 */
 359
 360#define CHUNKSZ                         32
 361#define nbits_to_hold_value(val)        fls(val)
 362#define BASEDEC 10              /* fancier cpuset lists input in decimal */
 363
 364/**
 365 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
 366 * @buf: byte buffer into which string is placed
 367 * @buflen: reserved size of @buf, in bytes
 368 * @maskp: pointer to bitmap to convert
 369 * @nmaskbits: size of bitmap, in bits
 370 *
 371 * Exactly @nmaskbits bits are displayed.  Hex digits are grouped into
 372 * comma-separated sets of eight digits per set.  Returns the number of
 373 * characters which were written to *buf, excluding the trailing \0.
 374 */
 375int bitmap_scnprintf(char *buf, unsigned int buflen,
 376        const unsigned long *maskp, int nmaskbits)
 377{
 378        int i, word, bit, len = 0;
 379        unsigned long val;
 380        const char *sep = "";
 381        int chunksz;
 382        u32 chunkmask;
 383
 384        chunksz = nmaskbits & (CHUNKSZ - 1);
 385        if (chunksz == 0)
 386                chunksz = CHUNKSZ;
 387
 388        i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
 389        for (; i >= 0; i -= CHUNKSZ) {
 390                chunkmask = ((1ULL << chunksz) - 1);
 391                word = i / BITS_PER_LONG;
 392                bit = i % BITS_PER_LONG;
 393                val = (maskp[word] >> bit) & chunkmask;
 394                len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
 395                        (chunksz+3)/4, val);
 396                chunksz = CHUNKSZ;
 397                sep = ",";
 398        }
 399        return len;
 400}
 401EXPORT_SYMBOL(bitmap_scnprintf);
 402
 403/**
 404 * __bitmap_parse - convert an ASCII hex string into a bitmap.
 405 * @buf: pointer to buffer containing string.
 406 * @buflen: buffer size in bytes.  If string is smaller than this
 407 *    then it must be terminated with a \0.
 408 * @is_user: location of buffer, 0 indicates kernel space
 409 * @maskp: pointer to bitmap array that will contain result.
 410 * @nmaskbits: size of bitmap, in bits.
 411 *
 412 * Commas group hex digits into chunks.  Each chunk defines exactly 32
 413 * bits of the resultant bitmask.  No chunk may specify a value larger
 414 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
 415 * then leading 0-bits are prepended.  %-EINVAL is returned for illegal
 416 * characters and for grouping errors such as "1,,5", ",44", "," and "".
 417 * Leading and trailing whitespace accepted, but not embedded whitespace.
 418 */
 419int __bitmap_parse(const char *buf, unsigned int buflen,
 420                int is_user, unsigned long *maskp,
 421                int nmaskbits)
 422{
 423        int c, old_c, totaldigits, ndigits, nchunks, nbits;
 424        u32 chunk;
 425        const char __user __force *ubuf = (const char __user __force *)buf;
 426
 427        bitmap_zero(maskp, nmaskbits);
 428
 429        nchunks = nbits = totaldigits = c = 0;
 430        do {
 431                chunk = ndigits = 0;
 432
 433                /* Get the next chunk of the bitmap */
 434                while (buflen) {
 435                        old_c = c;
 436                        if (is_user) {
 437                                if (__get_user(c, ubuf++))
 438                                        return -EFAULT;
 439                        }
 440                        else
 441                                c = *buf++;
 442                        buflen--;
 443                        if (isspace(c))
 444                                continue;
 445
 446                        /*
 447                         * If the last character was a space and the current
 448                         * character isn't '\0', we've got embedded whitespace.
 449                         * This is a no-no, so throw an error.
 450                         */
 451                        if (totaldigits && c && isspace(old_c))
 452                                return -EINVAL;
 453
 454                        /* A '\0' or a ',' signal the end of the chunk */
 455                        if (c == '\0' || c == ',')
 456                                break;
 457
 458                        if (!isxdigit(c))
 459                                return -EINVAL;
 460
 461                        /*
 462                         * Make sure there are at least 4 free bits in 'chunk'.
 463                         * If not, this hexdigit will overflow 'chunk', so
 464                         * throw an error.
 465                         */
 466                        if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
 467                                return -EOVERFLOW;
 468
 469                        chunk = (chunk << 4) | hex_to_bin(c);
 470                        ndigits++; totaldigits++;
 471                }
 472                if (ndigits == 0)
 473                        return -EINVAL;
 474                if (nchunks == 0 && chunk == 0)
 475                        continue;
 476
 477                __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
 478                *maskp |= chunk;
 479                nchunks++;
 480                nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
 481                if (nbits > nmaskbits)
 482                        return -EOVERFLOW;
 483        } while (buflen && c == ',');
 484
 485        return 0;
 486}
 487EXPORT_SYMBOL(__bitmap_parse);
 488
 489/**
 490 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
 491 *
 492 * @ubuf: pointer to user buffer containing string.
 493 * @ulen: buffer size in bytes.  If string is smaller than this
 494 *    then it must be terminated with a \0.
 495 * @maskp: pointer to bitmap array that will contain result.
 496 * @nmaskbits: size of bitmap, in bits.
 497 *
 498 * Wrapper for __bitmap_parse(), providing it with user buffer.
 499 *
 500 * We cannot have this as an inline function in bitmap.h because it needs
 501 * linux/uaccess.h to get the access_ok() declaration and this causes
 502 * cyclic dependencies.
 503 */
 504int bitmap_parse_user(const char __user *ubuf,
 505                        unsigned int ulen, unsigned long *maskp,
 506                        int nmaskbits)
 507{
 508        if (!access_ok(VERIFY_READ, ubuf, ulen))
 509                return -EFAULT;
 510        return __bitmap_parse((const char __force *)ubuf,
 511                                ulen, 1, maskp, nmaskbits);
 512
 513}
 514EXPORT_SYMBOL(bitmap_parse_user);
 515
 516/*
 517 * bscnl_emit(buf, buflen, rbot, rtop, bp)
 518 *
 519 * Helper routine for bitmap_scnlistprintf().  Write decimal number
 520 * or range to buf, suppressing output past buf+buflen, with optional
 521 * comma-prefix.  Return len of what was written to *buf, excluding the
 522 * trailing \0.
 523 */
 524static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
 525{
 526        if (len > 0)
 527                len += scnprintf(buf + len, buflen - len, ",");
 528        if (rbot == rtop)
 529                len += scnprintf(buf + len, buflen - len, "%d", rbot);
 530        else
 531                len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
 532        return len;
 533}
 534
 535/**
 536 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
 537 * @buf: byte buffer into which string is placed
 538 * @buflen: reserved size of @buf, in bytes
 539 * @maskp: pointer to bitmap to convert
 540 * @nmaskbits: size of bitmap, in bits
 541 *
 542 * Output format is a comma-separated list of decimal numbers and
 543 * ranges.  Consecutively set bits are shown as two hyphen-separated
 544 * decimal numbers, the smallest and largest bit numbers set in
 545 * the range.  Output format is compatible with the format
 546 * accepted as input by bitmap_parselist().
 547 *
 548 * The return value is the number of characters which were written to *buf
 549 * excluding the trailing '\0', as per ISO C99's scnprintf.
 550 */
 551int bitmap_scnlistprintf(char *buf, unsigned int buflen,
 552        const unsigned long *maskp, int nmaskbits)
 553{
 554        int len = 0;
 555        /* current bit is 'cur', most recently seen range is [rbot, rtop] */
 556        int cur, rbot, rtop;
 557
 558        if (buflen == 0)
 559                return 0;
 560        buf[0] = 0;
 561
 562        rbot = cur = find_first_bit(maskp, nmaskbits);
 563        while (cur < nmaskbits) {
 564                rtop = cur;
 565                cur = find_next_bit(maskp, nmaskbits, cur+1);
 566                if (cur >= nmaskbits || cur > rtop + 1) {
 567                        len = bscnl_emit(buf, buflen, rbot, rtop, len);
 568                        rbot = cur;
 569                }
 570        }
 571        return len;
 572}
 573EXPORT_SYMBOL(bitmap_scnlistprintf);
 574
 575/**
 576 * __bitmap_parselist - convert list format ASCII string to bitmap
 577 * @buf: read nul-terminated user string from this buffer
 578 * @buflen: buffer size in bytes.  If string is smaller than this
 579 *    then it must be terminated with a \0.
 580 * @is_user: location of buffer, 0 indicates kernel space
 581 * @maskp: write resulting mask here
 582 * @nmaskbits: number of bits in mask to be written
 583 *
 584 * Input format is a comma-separated list of decimal numbers and
 585 * ranges.  Consecutively set bits are shown as two hyphen-separated
 586 * decimal numbers, the smallest and largest bit numbers set in
 587 * the range.
 588 *
 589 * Returns 0 on success, -errno on invalid input strings.
 590 * Error values:
 591 *    %-EINVAL: second number in range smaller than first
 592 *    %-EINVAL: invalid character in string
 593 *    %-ERANGE: bit number specified too large for mask
 594 */
 595static int __bitmap_parselist(const char *buf, unsigned int buflen,
 596                int is_user, unsigned long *maskp,
 597                int nmaskbits)
 598{
 599        unsigned a, b;
 600        int c, old_c, totaldigits;
 601        const char __user __force *ubuf = (const char __user __force *)buf;
 602        int exp_digit, in_range;
 603
 604        totaldigits = c = 0;
 605        bitmap_zero(maskp, nmaskbits);
 606        do {
 607                exp_digit = 1;
 608                in_range = 0;
 609                a = b = 0;
 610
 611                /* Get the next cpu# or a range of cpu#'s */
 612                while (buflen) {
 613                        old_c = c;
 614                        if (is_user) {
 615                                if (__get_user(c, ubuf++))
 616                                        return -EFAULT;
 617                        } else
 618                                c = *buf++;
 619                        buflen--;
 620                        if (isspace(c))
 621                                continue;
 622
 623                        /*
 624                         * If the last character was a space and the current
 625                         * character isn't '\0', we've got embedded whitespace.
 626                         * This is a no-no, so throw an error.
 627                         */
 628                        if (totaldigits && c && isspace(old_c))
 629                                return -EINVAL;
 630
 631                        /* A '\0' or a ',' signal the end of a cpu# or range */
 632                        if (c == '\0' || c == ',')
 633                                break;
 634
 635                        if (c == '-') {
 636                                if (exp_digit || in_range)
 637                                        return -EINVAL;
 638                                b = 0;
 639                                in_range = 1;
 640                                exp_digit = 1;
 641                                continue;
 642                        }
 643
 644                        if (!isdigit(c))
 645                                return -EINVAL;
 646
 647                        b = b * 10 + (c - '0');
 648                        if (!in_range)
 649                                a = b;
 650                        exp_digit = 0;
 651                        totaldigits++;
 652                }
 653                if (!(a <= b))
 654                        return -EINVAL;
 655                if (b >= nmaskbits)
 656                        return -ERANGE;
 657                while (a <= b) {
 658                        set_bit(a, maskp);
 659                        a++;
 660                }
 661        } while (buflen && c == ',');
 662        return 0;
 663}
 664
 665int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
 666{
 667        char *nl  = strchr(bp, '\n');
 668        int len;
 669
 670        if (nl)
 671                len = nl - bp;
 672        else
 673                len = strlen(bp);
 674
 675        return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
 676}
 677EXPORT_SYMBOL(bitmap_parselist);
 678
 679
 680/**
 681 * bitmap_parselist_user()
 682 *
 683 * @ubuf: pointer to user buffer containing string.
 684 * @ulen: buffer size in bytes.  If string is smaller than this
 685 *    then it must be terminated with a \0.
 686 * @maskp: pointer to bitmap array that will contain result.
 687 * @nmaskbits: size of bitmap, in bits.
 688 *
 689 * Wrapper for bitmap_parselist(), providing it with user buffer.
 690 *
 691 * We cannot have this as an inline function in bitmap.h because it needs
 692 * linux/uaccess.h to get the access_ok() declaration and this causes
 693 * cyclic dependencies.
 694 */
 695int bitmap_parselist_user(const char __user *ubuf,
 696                        unsigned int ulen, unsigned long *maskp,
 697                        int nmaskbits)
 698{
 699        if (!access_ok(VERIFY_READ, ubuf, ulen))
 700                return -EFAULT;
 701        return __bitmap_parselist((const char __force *)ubuf,
 702                                        ulen, 1, maskp, nmaskbits);
 703}
 704EXPORT_SYMBOL(bitmap_parselist_user);
 705
 706
 707/**
 708 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
 709 *      @buf: pointer to a bitmap
 710 *      @pos: a bit position in @buf (0 <= @pos < @bits)
 711 *      @bits: number of valid bit positions in @buf
 712 *
 713 * Map the bit at position @pos in @buf (of length @bits) to the
 714 * ordinal of which set bit it is.  If it is not set or if @pos
 715 * is not a valid bit position, map to -1.
 716 *
 717 * If for example, just bits 4 through 7 are set in @buf, then @pos
 718 * values 4 through 7 will get mapped to 0 through 3, respectively,
 719 * and other @pos values will get mapped to 0.  When @pos value 7
 720 * gets mapped to (returns) @ord value 3 in this example, that means
 721 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
 722 *
 723 * The bit positions 0 through @bits are valid positions in @buf.
 724 */
 725static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
 726{
 727        int i, ord;
 728
 729        if (pos < 0 || pos >= bits || !test_bit(pos, buf))
 730                return -1;
 731
 732        i = find_first_bit(buf, bits);
 733        ord = 0;
 734        while (i < pos) {
 735                i = find_next_bit(buf, bits, i + 1);
 736                ord++;
 737        }
 738        BUG_ON(i != pos);
 739
 740        return ord;
 741}
 742
 743/**
 744 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
 745 *      @buf: pointer to bitmap
 746 *      @ord: ordinal bit position (n-th set bit, n >= 0)
 747 *      @bits: number of valid bit positions in @buf
 748 *
 749 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
 750 * Value of @ord should be in range 0 <= @ord < weight(buf), else
 751 * results are undefined.
 752 *
 753 * If for example, just bits 4 through 7 are set in @buf, then @ord
 754 * values 0 through 3 will get mapped to 4 through 7, respectively,
 755 * and all other @ord values return undefined values.  When @ord value 3
 756 * gets mapped to (returns) @pos value 7 in this example, that means
 757 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
 758 *
 759 * The bit positions 0 through @bits are valid positions in @buf.
 760 */
 761int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
 762{
 763        int pos = 0;
 764
 765        if (ord >= 0 && ord < bits) {
 766                int i;
 767
 768                for (i = find_first_bit(buf, bits);
 769                     i < bits && ord > 0;
 770                     i = find_next_bit(buf, bits, i + 1))
 771                        ord--;
 772                if (i < bits && ord == 0)
 773                        pos = i;
 774        }
 775
 776        return pos;
 777}
 778
 779/**
 780 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
 781 *      @dst: remapped result
 782 *      @src: subset to be remapped
 783 *      @old: defines domain of map
 784 *      @new: defines range of map
 785 *      @bits: number of bits in each of these bitmaps
 786 *
 787 * Let @old and @new define a mapping of bit positions, such that
 788 * whatever position is held by the n-th set bit in @old is mapped
 789 * to the n-th set bit in @new.  In the more general case, allowing
 790 * for the possibility that the weight 'w' of @new is less than the
 791 * weight of @old, map the position of the n-th set bit in @old to
 792 * the position of the m-th set bit in @new, where m == n % w.
 793 *
 794 * If either of the @old and @new bitmaps are empty, or if @src and
 795 * @dst point to the same location, then this routine copies @src
 796 * to @dst.
 797 *
 798 * The positions of unset bits in @old are mapped to themselves
 799 * (the identify map).
 800 *
 801 * Apply the above specified mapping to @src, placing the result in
 802 * @dst, clearing any bits previously set in @dst.
 803 *
 804 * For example, lets say that @old has bits 4 through 7 set, and
 805 * @new has bits 12 through 15 set.  This defines the mapping of bit
 806 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
 807 * bit positions unchanged.  So if say @src comes into this routine
 808 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
 809 * 13 and 15 set.
 810 */
 811void bitmap_remap(unsigned long *dst, const unsigned long *src,
 812                const unsigned long *old, const unsigned long *new,
 813                int bits)
 814{
 815        int oldbit, w;
 816
 817        if (dst == src)         /* following doesn't handle inplace remaps */
 818                return;
 819        bitmap_zero(dst, bits);
 820
 821        w = bitmap_weight(new, bits);
 822        for_each_set_bit(oldbit, src, bits) {
 823                int n = bitmap_pos_to_ord(old, oldbit, bits);
 824
 825                if (n < 0 || w == 0)
 826                        set_bit(oldbit, dst);   /* identity map */
 827                else
 828                        set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
 829        }
 830}
 831EXPORT_SYMBOL(bitmap_remap);
 832
 833/**
 834 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
 835 *      @oldbit: bit position to be mapped
 836 *      @old: defines domain of map
 837 *      @new: defines range of map
 838 *      @bits: number of bits in each of these bitmaps
 839 *
 840 * Let @old and @new define a mapping of bit positions, such that
 841 * whatever position is held by the n-th set bit in @old is mapped
 842 * to the n-th set bit in @new.  In the more general case, allowing
 843 * for the possibility that the weight 'w' of @new is less than the
 844 * weight of @old, map the position of the n-th set bit in @old to
 845 * the position of the m-th set bit in @new, where m == n % w.
 846 *
 847 * The positions of unset bits in @old are mapped to themselves
 848 * (the identify map).
 849 *
 850 * Apply the above specified mapping to bit position @oldbit, returning
 851 * the new bit position.
 852 *
 853 * For example, lets say that @old has bits 4 through 7 set, and
 854 * @new has bits 12 through 15 set.  This defines the mapping of bit
 855 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
 856 * bit positions unchanged.  So if say @oldbit is 5, then this routine
 857 * returns 13.
 858 */
 859int bitmap_bitremap(int oldbit, const unsigned long *old,
 860                                const unsigned long *new, int bits)
 861{
 862        int w = bitmap_weight(new, bits);
 863        int n = bitmap_pos_to_ord(old, oldbit, bits);
 864        if (n < 0 || w == 0)
 865                return oldbit;
 866        else
 867                return bitmap_ord_to_pos(new, n % w, bits);
 868}
 869EXPORT_SYMBOL(bitmap_bitremap);
 870
 871/**
 872 * bitmap_onto - translate one bitmap relative to another
 873 *      @dst: resulting translated bitmap
 874 *      @orig: original untranslated bitmap
 875 *      @relmap: bitmap relative to which translated
 876 *      @bits: number of bits in each of these bitmaps
 877 *
 878 * Set the n-th bit of @dst iff there exists some m such that the
 879 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
 880 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
 881 * (If you understood the previous sentence the first time your
 882 * read it, you're overqualified for your current job.)
 883 *
 884 * In other words, @orig is mapped onto (surjectively) @dst,
 885 * using the the map { <n, m> | the n-th bit of @relmap is the
 886 * m-th set bit of @relmap }.
 887 *
 888 * Any set bits in @orig above bit number W, where W is the
 889 * weight of (number of set bits in) @relmap are mapped nowhere.
 890 * In particular, if for all bits m set in @orig, m >= W, then
 891 * @dst will end up empty.  In situations where the possibility
 892 * of such an empty result is not desired, one way to avoid it is
 893 * to use the bitmap_fold() operator, below, to first fold the
 894 * @orig bitmap over itself so that all its set bits x are in the
 895 * range 0 <= x < W.  The bitmap_fold() operator does this by
 896 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
 897 *
 898 * Example [1] for bitmap_onto():
 899 *  Let's say @relmap has bits 30-39 set, and @orig has bits
 900 *  1, 3, 5, 7, 9 and 11 set.  Then on return from this routine,
 901 *  @dst will have bits 31, 33, 35, 37 and 39 set.
 902 *
 903 *  When bit 0 is set in @orig, it means turn on the bit in
 904 *  @dst corresponding to whatever is the first bit (if any)
 905 *  that is turned on in @relmap.  Since bit 0 was off in the
 906 *  above example, we leave off that bit (bit 30) in @dst.
 907 *
 908 *  When bit 1 is set in @orig (as in the above example), it
 909 *  means turn on the bit in @dst corresponding to whatever
 910 *  is the second bit that is turned on in @relmap.  The second
 911 *  bit in @relmap that was turned on in the above example was
 912 *  bit 31, so we turned on bit 31 in @dst.
 913 *
 914 *  Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
 915 *  because they were the 4th, 6th, 8th and 10th set bits
 916 *  set in @relmap, and the 4th, 6th, 8th and 10th bits of
 917 *  @orig (i.e. bits 3, 5, 7 and 9) were also set.
 918 *
 919 *  When bit 11 is set in @orig, it means turn on the bit in
 920 *  @dst corresponding to whatever is the twelfth bit that is
 921 *  turned on in @relmap.  In the above example, there were
 922 *  only ten bits turned on in @relmap (30..39), so that bit
 923 *  11 was set in @orig had no affect on @dst.
 924 *
 925 * Example [2] for bitmap_fold() + bitmap_onto():
 926 *  Let's say @relmap has these ten bits set:
 927 *              40 41 42 43 45 48 53 61 74 95
 928 *  (for the curious, that's 40 plus the first ten terms of the
 929 *  Fibonacci sequence.)
 930 *
 931 *  Further lets say we use the following code, invoking
 932 *  bitmap_fold() then bitmap_onto, as suggested above to
 933 *  avoid the possitility of an empty @dst result:
 934 *
 935 *      unsigned long *tmp;     // a temporary bitmap's bits
 936 *
 937 *      bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
 938 *      bitmap_onto(dst, tmp, relmap, bits);
 939 *
 940 *  Then this table shows what various values of @dst would be, for
 941 *  various @orig's.  I list the zero-based positions of each set bit.
 942 *  The tmp column shows the intermediate result, as computed by
 943 *  using bitmap_fold() to fold the @orig bitmap modulo ten
 944 *  (the weight of @relmap).
 945 *
 946 *      @orig           tmp            @dst
 947 *      0                0             40
 948 *      1                1             41
 949 *      9                9             95
 950 *      10               0             40 (*)
 951 *      1 3 5 7          1 3 5 7       41 43 48 61
 952 *      0 1 2 3 4        0 1 2 3 4     40 41 42 43 45
 953 *      0 9 18 27        0 9 8 7       40 61 74 95
 954 *      0 10 20 30       0             40
 955 *      0 11 22 33       0 1 2 3       40 41 42 43
 956 *      0 12 24 36       0 2 4 6       40 42 45 53
 957 *      78 102 211       1 2 8         41 42 74 (*)
 958 *
 959 * (*) For these marked lines, if we hadn't first done bitmap_fold()
 960 *     into tmp, then the @dst result would have been empty.
 961 *
 962 * If either of @orig or @relmap is empty (no set bits), then @dst
 963 * will be returned empty.
 964 *
 965 * If (as explained above) the only set bits in @orig are in positions
 966 * m where m >= W, (where W is the weight of @relmap) then @dst will
 967 * once again be returned empty.
 968 *
 969 * All bits in @dst not set by the above rule are cleared.
 970 */
 971void bitmap_onto(unsigned long *dst, const unsigned long *orig,
 972                        const unsigned long *relmap, int bits)
 973{
 974        int n, m;               /* same meaning as in above comment */
 975
 976        if (dst == orig)        /* following doesn't handle inplace mappings */
 977                return;
 978        bitmap_zero(dst, bits);
 979
 980        /*
 981         * The following code is a more efficient, but less
 982         * obvious, equivalent to the loop:
 983         *      for (m = 0; m < bitmap_weight(relmap, bits); m++) {
 984         *              n = bitmap_ord_to_pos(orig, m, bits);
 985         *              if (test_bit(m, orig))
 986         *                      set_bit(n, dst);
 987         *      }
 988         */
 989
 990        m = 0;
 991        for_each_set_bit(n, relmap, bits) {
 992                /* m == bitmap_pos_to_ord(relmap, n, bits) */
 993                if (test_bit(m, orig))
 994                        set_bit(n, dst);
 995                m++;
 996        }
 997}
 998EXPORT_SYMBOL(bitmap_onto);
 999
1000/**
1001 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1002 *      @dst: resulting smaller bitmap
1003 *      @orig: original larger bitmap
1004 *      @sz: specified size
1005 *      @bits: number of bits in each of these bitmaps
1006 *
1007 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1008 * Clear all other bits in @dst.  See further the comment and
1009 * Example [2] for bitmap_onto() for why and how to use this.
1010 */
1011void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1012                        int sz, int bits)
1013{
1014        int oldbit;
1015
1016        if (dst == orig)        /* following doesn't handle inplace mappings */
1017                return;
1018        bitmap_zero(dst, bits);
1019
1020        for_each_set_bit(oldbit, orig, bits)
1021                set_bit(oldbit % sz, dst);
1022}
1023EXPORT_SYMBOL(bitmap_fold);
1024
1025/*
1026 * Common code for bitmap_*_region() routines.
1027 *      bitmap: array of unsigned longs corresponding to the bitmap
1028 *      pos: the beginning of the region
1029 *      order: region size (log base 2 of number of bits)
1030 *      reg_op: operation(s) to perform on that region of bitmap
1031 *
1032 * Can set, verify and/or release a region of bits in a bitmap,
1033 * depending on which combination of REG_OP_* flag bits is set.
1034 *
1035 * A region of a bitmap is a sequence of bits in the bitmap, of
1036 * some size '1 << order' (a power of two), aligned to that same
1037 * '1 << order' power of two.
1038 *
1039 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1040 * Returns 0 in all other cases and reg_ops.
1041 */
1042
1043enum {
1044        REG_OP_ISFREE,          /* true if region is all zero bits */
1045        REG_OP_ALLOC,           /* set all bits in region */
1046        REG_OP_RELEASE,         /* clear all bits in region */
1047};
1048
1049static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op)
1050{
1051        int nbits_reg;          /* number of bits in region */
1052        int index;              /* index first long of region in bitmap */
1053        int offset;             /* bit offset region in bitmap[index] */
1054        int nlongs_reg;         /* num longs spanned by region in bitmap */
1055        int nbitsinlong;        /* num bits of region in each spanned long */
1056        unsigned long mask;     /* bitmask for one long of region */
1057        int i;                  /* scans bitmap by longs */
1058        int ret = 0;            /* return value */
1059
1060        /*
1061         * Either nlongs_reg == 1 (for small orders that fit in one long)
1062         * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1063         */
1064        nbits_reg = 1 << order;
1065        index = pos / BITS_PER_LONG;
1066        offset = pos - (index * BITS_PER_LONG);
1067        nlongs_reg = BITS_TO_LONGS(nbits_reg);
1068        nbitsinlong = min(nbits_reg,  BITS_PER_LONG);
1069
1070        /*
1071         * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1072         * overflows if nbitsinlong == BITS_PER_LONG.
1073         */
1074        mask = (1UL << (nbitsinlong - 1));
1075        mask += mask - 1;
1076        mask <<= offset;
1077
1078        switch (reg_op) {
1079        case REG_OP_ISFREE:
1080                for (i = 0; i < nlongs_reg; i++) {
1081                        if (bitmap[index + i] & mask)
1082                                goto done;
1083                }
1084                ret = 1;        /* all bits in region free (zero) */
1085                break;
1086
1087        case REG_OP_ALLOC:
1088                for (i = 0; i < nlongs_reg; i++)
1089                        bitmap[index + i] |= mask;
1090                break;
1091
1092        case REG_OP_RELEASE:
1093                for (i = 0; i < nlongs_reg; i++)
1094                        bitmap[index + i] &= ~mask;
1095                break;
1096        }
1097done:
1098        return ret;
1099}
1100
1101/**
1102 * bitmap_find_free_region - find a contiguous aligned mem region
1103 *      @bitmap: array of unsigned longs corresponding to the bitmap
1104 *      @bits: number of bits in the bitmap
1105 *      @order: region size (log base 2 of number of bits) to find
1106 *
1107 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1108 * allocate them (set them to one).  Only consider regions of length
1109 * a power (@order) of two, aligned to that power of two, which
1110 * makes the search algorithm much faster.
1111 *
1112 * Return the bit offset in bitmap of the allocated region,
1113 * or -errno on failure.
1114 */
1115int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
1116{
1117        int pos, end;           /* scans bitmap by regions of size order */
1118
1119        for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) {
1120                if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1121                        continue;
1122                __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1123                return pos;
1124        }
1125        return -ENOMEM;
1126}
1127EXPORT_SYMBOL(bitmap_find_free_region);
1128
1129/**
1130 * bitmap_release_region - release allocated bitmap region
1131 *      @bitmap: array of unsigned longs corresponding to the bitmap
1132 *      @pos: beginning of bit region to release
1133 *      @order: region size (log base 2 of number of bits) to release
1134 *
1135 * This is the complement to __bitmap_find_free_region() and releases
1136 * the found region (by clearing it in the bitmap).
1137 *
1138 * No return value.
1139 */
1140void bitmap_release_region(unsigned long *bitmap, int pos, int order)
1141{
1142        __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1143}
1144EXPORT_SYMBOL(bitmap_release_region);
1145
1146/**
1147 * bitmap_allocate_region - allocate bitmap region
1148 *      @bitmap: array of unsigned longs corresponding to the bitmap
1149 *      @pos: beginning of bit region to allocate
1150 *      @order: region size (log base 2 of number of bits) to allocate
1151 *
1152 * Allocate (set bits in) a specified region of a bitmap.
1153 *
1154 * Return 0 on success, or %-EBUSY if specified region wasn't
1155 * free (not all bits were zero).
1156 */
1157int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
1158{
1159        if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1160                return -EBUSY;
1161        __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1162        return 0;
1163}
1164EXPORT_SYMBOL(bitmap_allocate_region);
1165
1166/**
1167 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1168 * @dst:   destination buffer
1169 * @src:   bitmap to copy
1170 * @nbits: number of bits in the bitmap
1171 *
1172 * Require nbits % BITS_PER_LONG == 0.
1173 */
1174void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1175{
1176        unsigned long *d = dst;
1177        int i;
1178
1179        for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1180                if (BITS_PER_LONG == 64)
1181                        d[i] = cpu_to_le64(src[i]);
1182                else
1183                        d[i] = cpu_to_le32(src[i]);
1184        }
1185}
1186EXPORT_SYMBOL(bitmap_copy_le);
1187
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