1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * lib/bitmap.c 4 * Helper functions for bitmap.h. 5 */ 6 #include <linux/export.h> 7 #include <linux/thread_info.h> 8 #include <linux/ctype.h> 9 #include <linux/errno.h> 10 #include <linux/bitmap.h> 11 #include <linux/bitops.h> 12 #include <linux/bug.h> 13 #include <linux/kernel.h> 14 #include <linux/mm.h> 15 #include <linux/slab.h> 16 #include <linux/string.h> 17 #include <linux/uaccess.h> 18 19 #include <asm/page.h> 20 21 #include "kstrtox.h" 22 23 /** 24 * DOC: bitmap introduction 25 * 26 * bitmaps provide an array of bits, implemented using an an 27 * array of unsigned longs. The number of valid bits in a 28 * given bitmap does _not_ need to be an exact multiple of 29 * BITS_PER_LONG. 30 * 31 * The possible unused bits in the last, partially used word 32 * of a bitmap are 'don't care'. The implementation makes 33 * no particular effort to keep them zero. It ensures that 34 * their value will not affect the results of any operation. 35 * The bitmap operations that return Boolean (bitmap_empty, 36 * for example) or scalar (bitmap_weight, for example) results 37 * carefully filter out these unused bits from impacting their 38 * results. 39 * 40 * The byte ordering of bitmaps is more natural on little 41 * endian architectures. See the big-endian headers 42 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h 43 * for the best explanations of this ordering. 44 */ 45 46 int __bitmap_equal(const unsigned long *bitmap1, 47 const unsigned long *bitmap2, unsigned int bits) 48 { 49 unsigned int k, lim = bits/BITS_PER_LONG; 50 for (k = 0; k < lim; ++k) 51 if (bitmap1[k] != bitmap2[k]) 52 return 0; 53 54 if (bits % BITS_PER_LONG) 55 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 56 return 0; 57 58 return 1; 59 } 60 EXPORT_SYMBOL(__bitmap_equal); 61 62 bool __bitmap_or_equal(const unsigned long *bitmap1, 63 const unsigned long *bitmap2, 64 const unsigned long *bitmap3, 65 unsigned int bits) 66 { 67 unsigned int k, lim = bits / BITS_PER_LONG; 68 unsigned long tmp; 69 70 for (k = 0; k < lim; ++k) { 71 if ((bitmap1[k] | bitmap2[k]) != bitmap3[k]) 72 return false; 73 } 74 75 if (!(bits % BITS_PER_LONG)) 76 return true; 77 78 tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k]; 79 return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0; 80 } 81 82 void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits) 83 { 84 unsigned int k, lim = BITS_TO_LONGS(bits); 85 for (k = 0; k < lim; ++k) 86 dst[k] = ~src[k]; 87 } 88 EXPORT_SYMBOL(__bitmap_complement); 89 90 /** 91 * __bitmap_shift_right - logical right shift of the bits in a bitmap 92 * @dst : destination bitmap 93 * @src : source bitmap 94 * @shift : shift by this many bits 95 * @nbits : bitmap size, in bits 96 * 97 * Shifting right (dividing) means moving bits in the MS -> LS bit 98 * direction. Zeros are fed into the vacated MS positions and the 99 * LS bits shifted off the bottom are lost. 100 */ 101 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, 102 unsigned shift, unsigned nbits) 103 { 104 unsigned k, lim = BITS_TO_LONGS(nbits); 105 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; 106 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); 107 for (k = 0; off + k < lim; ++k) { 108 unsigned long upper, lower; 109 110 /* 111 * If shift is not word aligned, take lower rem bits of 112 * word above and make them the top rem bits of result. 113 */ 114 if (!rem || off + k + 1 >= lim) 115 upper = 0; 116 else { 117 upper = src[off + k + 1]; 118 if (off + k + 1 == lim - 1) 119 upper &= mask; 120 upper <<= (BITS_PER_LONG - rem); 121 } 122 lower = src[off + k]; 123 if (off + k == lim - 1) 124 lower &= mask; 125 lower >>= rem; 126 dst[k] = lower | upper; 127 } 128 if (off) 129 memset(&dst[lim - off], 0, off*sizeof(unsigned long)); 130 } 131 EXPORT_SYMBOL(__bitmap_shift_right); 132 133 134 /** 135 * __bitmap_shift_left - logical left shift of the bits in a bitmap 136 * @dst : destination bitmap 137 * @src : source bitmap 138 * @shift : shift by this many bits 139 * @nbits : bitmap size, in bits 140 * 141 * Shifting left (multiplying) means moving bits in the LS -> MS 142 * direction. Zeros are fed into the vacated LS bit positions 143 * and those MS bits shifted off the top are lost. 144 */ 145 146 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, 147 unsigned int shift, unsigned int nbits) 148 { 149 int k; 150 unsigned int lim = BITS_TO_LONGS(nbits); 151 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; 152 for (k = lim - off - 1; k >= 0; --k) { 153 unsigned long upper, lower; 154 155 /* 156 * If shift is not word aligned, take upper rem bits of 157 * word below and make them the bottom rem bits of result. 158 */ 159 if (rem && k > 0) 160 lower = src[k - 1] >> (BITS_PER_LONG - rem); 161 else 162 lower = 0; 163 upper = src[k] << rem; 164 dst[k + off] = lower | upper; 165 } 166 if (off) 167 memset(dst, 0, off*sizeof(unsigned long)); 168 } 169 EXPORT_SYMBOL(__bitmap_shift_left); 170 171 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, 172 const unsigned long *bitmap2, unsigned int bits) 173 { 174 unsigned int k; 175 unsigned int lim = bits/BITS_PER_LONG; 176 unsigned long result = 0; 177 178 for (k = 0; k < lim; k++) 179 result |= (dst[k] = bitmap1[k] & bitmap2[k]); 180 if (bits % BITS_PER_LONG) 181 result |= (dst[k] = bitmap1[k] & bitmap2[k] & 182 BITMAP_LAST_WORD_MASK(bits)); 183 return result != 0; 184 } 185 EXPORT_SYMBOL(__bitmap_and); 186 187 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, 188 const unsigned long *bitmap2, unsigned int bits) 189 { 190 unsigned int k; 191 unsigned int nr = BITS_TO_LONGS(bits); 192 193 for (k = 0; k < nr; k++) 194 dst[k] = bitmap1[k] | bitmap2[k]; 195 } 196 EXPORT_SYMBOL(__bitmap_or); 197 198 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, 199 const unsigned long *bitmap2, unsigned int bits) 200 { 201 unsigned int k; 202 unsigned int nr = BITS_TO_LONGS(bits); 203 204 for (k = 0; k < nr; k++) 205 dst[k] = bitmap1[k] ^ bitmap2[k]; 206 } 207 EXPORT_SYMBOL(__bitmap_xor); 208 209 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, 210 const unsigned long *bitmap2, unsigned int bits) 211 { 212 unsigned int k; 213 unsigned int lim = bits/BITS_PER_LONG; 214 unsigned long result = 0; 215 216 for (k = 0; k < lim; k++) 217 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); 218 if (bits % BITS_PER_LONG) 219 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & 220 BITMAP_LAST_WORD_MASK(bits)); 221 return result != 0; 222 } 223 EXPORT_SYMBOL(__bitmap_andnot); 224 225 int __bitmap_intersects(const unsigned long *bitmap1, 226 const unsigned long *bitmap2, unsigned int bits) 227 { 228 unsigned int k, lim = bits/BITS_PER_LONG; 229 for (k = 0; k < lim; ++k) 230 if (bitmap1[k] & bitmap2[k]) 231 return 1; 232 233 if (bits % BITS_PER_LONG) 234 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 235 return 1; 236 return 0; 237 } 238 EXPORT_SYMBOL(__bitmap_intersects); 239 240 int __bitmap_subset(const unsigned long *bitmap1, 241 const unsigned long *bitmap2, unsigned int bits) 242 { 243 unsigned int k, lim = bits/BITS_PER_LONG; 244 for (k = 0; k < lim; ++k) 245 if (bitmap1[k] & ~bitmap2[k]) 246 return 0; 247 248 if (bits % BITS_PER_LONG) 249 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 250 return 0; 251 return 1; 252 } 253 EXPORT_SYMBOL(__bitmap_subset); 254 255 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) 256 { 257 unsigned int k, lim = bits/BITS_PER_LONG; 258 int w = 0; 259 260 for (k = 0; k < lim; k++) 261 w += hweight_long(bitmap[k]); 262 263 if (bits % BITS_PER_LONG) 264 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); 265 266 return w; 267 } 268 EXPORT_SYMBOL(__bitmap_weight); 269 270 void __bitmap_set(unsigned long *map, unsigned int start, int len) 271 { 272 unsigned long *p = map + BIT_WORD(start); 273 const unsigned int size = start + len; 274 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); 275 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); 276 277 while (len - bits_to_set >= 0) { 278 *p |= mask_to_set; 279 len -= bits_to_set; 280 bits_to_set = BITS_PER_LONG; 281 mask_to_set = ~0UL; 282 p++; 283 } 284 if (len) { 285 mask_to_set &= BITMAP_LAST_WORD_MASK(size); 286 *p |= mask_to_set; 287 } 288 } 289 EXPORT_SYMBOL(__bitmap_set); 290 291 void __bitmap_clear(unsigned long *map, unsigned int start, int len) 292 { 293 unsigned long *p = map + BIT_WORD(start); 294 const unsigned int size = start + len; 295 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); 296 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); 297 298 while (len - bits_to_clear >= 0) { 299 *p &= ~mask_to_clear; 300 len -= bits_to_clear; 301 bits_to_clear = BITS_PER_LONG; 302 mask_to_clear = ~0UL; 303 p++; 304 } 305 if (len) { 306 mask_to_clear &= BITMAP_LAST_WORD_MASK(size); 307 *p &= ~mask_to_clear; 308 } 309 } 310 EXPORT_SYMBOL(__bitmap_clear); 311 312 /** 313 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area 314 * @map: The address to base the search on 315 * @size: The bitmap size in bits 316 * @start: The bitnumber to start searching at 317 * @nr: The number of zeroed bits we're looking for 318 * @align_mask: Alignment mask for zero area 319 * @align_offset: Alignment offset for zero area. 320 * 321 * The @align_mask should be one less than a power of 2; the effect is that 322 * the bit offset of all zero areas this function finds plus @align_offset 323 * is multiple of that power of 2. 324 */ 325 unsigned long bitmap_find_next_zero_area_off(unsigned long *map, 326 unsigned long size, 327 unsigned long start, 328 unsigned int nr, 329 unsigned long align_mask, 330 unsigned long align_offset) 331 { 332 unsigned long index, end, i; 333 again: 334 index = find_next_zero_bit(map, size, start); 335 336 /* Align allocation */ 337 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset; 338 339 end = index + nr; 340 if (end > size) 341 return end; 342 i = find_next_bit(map, end, index); 343 if (i < end) { 344 start = i + 1; 345 goto again; 346 } 347 return index; 348 } 349 EXPORT_SYMBOL(bitmap_find_next_zero_area_off); 350 351 /* 352 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers, 353 * second version by Paul Jackson, third by Joe Korty. 354 */ 355 356 #define CHUNKSZ 32 357 #define nbits_to_hold_value(val) fls(val) 358 #define BASEDEC 10 /* fancier cpuset lists input in decimal */ 359 360 /** 361 * __bitmap_parse - convert an ASCII hex string into a bitmap. 362 * @buf: pointer to buffer containing string. 363 * @buflen: buffer size in bytes. If string is smaller than this 364 * then it must be terminated with a \0. 365 * @is_user: location of buffer, 0 indicates kernel space 366 * @maskp: pointer to bitmap array that will contain result. 367 * @nmaskbits: size of bitmap, in bits. 368 * 369 * Commas group hex digits into chunks. Each chunk defines exactly 32 370 * bits of the resultant bitmask. No chunk may specify a value larger 371 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value 372 * then leading 0-bits are prepended. %-EINVAL is returned for illegal 373 * characters and for grouping errors such as "1,,5", ",44", "," and "". 374 * Leading and trailing whitespace accepted, but not embedded whitespace. 375 */ 376 int __bitmap_parse(const char *buf, unsigned int buflen, 377 int is_user, unsigned long *maskp, 378 int nmaskbits) 379 { 380 int c, old_c, totaldigits, ndigits, nchunks, nbits; 381 u32 chunk; 382 const char __user __force *ubuf = (const char __user __force *)buf; 383 384 bitmap_zero(maskp, nmaskbits); 385 386 nchunks = nbits = totaldigits = c = 0; 387 do { 388 chunk = 0; 389 ndigits = totaldigits; 390 391 /* Get the next chunk of the bitmap */ 392 while (buflen) { 393 old_c = c; 394 if (is_user) { 395 if (__get_user(c, ubuf++)) 396 return -EFAULT; 397 } 398 else 399 c = *buf++; 400 buflen--; 401 if (isspace(c)) 402 continue; 403 404 /* 405 * If the last character was a space and the current 406 * character isn't '\0', we've got embedded whitespace. 407 * This is a no-no, so throw an error. 408 */ 409 if (totaldigits && c && isspace(old_c)) 410 return -EINVAL; 411 412 /* A '\0' or a ',' signal the end of the chunk */ 413 if (c == '\0' || c == ',') 414 break; 415 416 if (!isxdigit(c)) 417 return -EINVAL; 418 419 /* 420 * Make sure there are at least 4 free bits in 'chunk'. 421 * If not, this hexdigit will overflow 'chunk', so 422 * throw an error. 423 */ 424 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) 425 return -EOVERFLOW; 426 427 chunk = (chunk << 4) | hex_to_bin(c); 428 totaldigits++; 429 } 430 if (ndigits == totaldigits) 431 return -EINVAL; 432 if (nchunks == 0 && chunk == 0) 433 continue; 434 435 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); 436 *maskp |= chunk; 437 nchunks++; 438 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; 439 if (nbits > nmaskbits) 440 return -EOVERFLOW; 441 } while (buflen && c == ','); 442 443 return 0; 444 } 445 EXPORT_SYMBOL(__bitmap_parse); 446 447 /** 448 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap 449 * 450 * @ubuf: pointer to user buffer containing string. 451 * @ulen: buffer size in bytes. If string is smaller than this 452 * then it must be terminated with a \0. 453 * @maskp: pointer to bitmap array that will contain result. 454 * @nmaskbits: size of bitmap, in bits. 455 * 456 * Wrapper for __bitmap_parse(), providing it with user buffer. 457 * 458 * We cannot have this as an inline function in bitmap.h because it needs 459 * linux/uaccess.h to get the access_ok() declaration and this causes 460 * cyclic dependencies. 461 */ 462 int bitmap_parse_user(const char __user *ubuf, 463 unsigned int ulen, unsigned long *maskp, 464 int nmaskbits) 465 { 466 if (!access_ok(ubuf, ulen)) 467 return -EFAULT; 468 return __bitmap_parse((const char __force *)ubuf, 469 ulen, 1, maskp, nmaskbits); 470 471 } 472 EXPORT_SYMBOL(bitmap_parse_user); 473 474 /** 475 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string 476 * @list: indicates whether the bitmap must be list 477 * @buf: page aligned buffer into which string is placed 478 * @maskp: pointer to bitmap to convert 479 * @nmaskbits: size of bitmap, in bits 480 * 481 * Output format is a comma-separated list of decimal numbers and 482 * ranges if list is specified or hex digits grouped into comma-separated 483 * sets of 8 digits/set. Returns the number of characters written to buf. 484 * 485 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned 486 * area and that sufficient storage remains at @buf to accommodate the 487 * bitmap_print_to_pagebuf() output. Returns the number of characters 488 * actually printed to @buf, excluding terminating '\0'. 489 */ 490 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, 491 int nmaskbits) 492 { 493 ptrdiff_t len = PAGE_SIZE - offset_in_page(buf); 494 495 return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : 496 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); 497 } 498 EXPORT_SYMBOL(bitmap_print_to_pagebuf); 499 500 /* 501 * Region 9-38:4/10 describes the following bitmap structure: 502 * 0 9 12 18 38 503 * .........****......****......****...... 504 * ^ ^ ^ ^ 505 * start off group_len end 506 */ 507 struct region { 508 unsigned int start; 509 unsigned int off; 510 unsigned int group_len; 511 unsigned int end; 512 }; 513 514 static int bitmap_set_region(const struct region *r, 515 unsigned long *bitmap, int nbits) 516 { 517 unsigned int start; 518 519 if (r->end >= nbits) 520 return -ERANGE; 521 522 for (start = r->start; start <= r->end; start += r->group_len) 523 bitmap_set(bitmap, start, min(r->end - start + 1, r->off)); 524 525 return 0; 526 } 527 528 static int bitmap_check_region(const struct region *r) 529 { 530 if (r->start > r->end || r->group_len == 0 || r->off > r->group_len) 531 return -EINVAL; 532 533 return 0; 534 } 535 536 static const char *bitmap_getnum(const char *str, unsigned int *num) 537 { 538 unsigned long long n; 539 unsigned int len; 540 541 len = _parse_integer(str, 10, &n); 542 if (!len) 543 return ERR_PTR(-EINVAL); 544 if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n) 545 return ERR_PTR(-EOVERFLOW); 546 547 *num = n; 548 return str + len; 549 } 550 551 static inline bool end_of_str(char c) 552 { 553 return c == '\0' || c == '\n'; 554 } 555 556 static inline bool __end_of_region(char c) 557 { 558 return isspace(c) || c == ','; 559 } 560 561 static inline bool end_of_region(char c) 562 { 563 return __end_of_region(c) || end_of_str(c); 564 } 565 566 /* 567 * The format allows commas and whitespases at the beginning 568 * of the region. 569 */ 570 static const char *bitmap_find_region(const char *str) 571 { 572 while (__end_of_region(*str)) 573 str++; 574 575 return end_of_str(*str) ? NULL : str; 576 } 577 578 static const char *bitmap_parse_region(const char *str, struct region *r) 579 { 580 str = bitmap_getnum(str, &r->start); 581 if (IS_ERR(str)) 582 return str; 583 584 if (end_of_region(*str)) 585 goto no_end; 586 587 if (*str != '-') 588 return ERR_PTR(-EINVAL); 589 590 str = bitmap_getnum(str + 1, &r->end); 591 if (IS_ERR(str)) 592 return str; 593 594 if (end_of_region(*str)) 595 goto no_pattern; 596 597 if (*str != ':') 598 return ERR_PTR(-EINVAL); 599 600 str = bitmap_getnum(str + 1, &r->off); 601 if (IS_ERR(str)) 602 return str; 603 604 if (*str != '/') 605 return ERR_PTR(-EINVAL); 606 607 return bitmap_getnum(str + 1, &r->group_len); 608 609 no_end: 610 r->end = r->start; 611 no_pattern: 612 r->off = r->end + 1; 613 r->group_len = r->end + 1; 614 615 return end_of_str(*str) ? NULL : str; 616 } 617 618 /** 619 * bitmap_parselist - convert list format ASCII string to bitmap 620 * @buf: read user string from this buffer; must be terminated 621 * with a \0 or \n. 622 * @maskp: write resulting mask here 623 * @nmaskbits: number of bits in mask to be written 624 * 625 * Input format is a comma-separated list of decimal numbers and 626 * ranges. Consecutively set bits are shown as two hyphen-separated 627 * decimal numbers, the smallest and largest bit numbers set in 628 * the range. 629 * Optionally each range can be postfixed to denote that only parts of it 630 * should be set. The range will divided to groups of specific size. 631 * From each group will be used only defined amount of bits. 632 * Syntax: range:used_size/group_size 633 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769 634 * 635 * Returns: 0 on success, -errno on invalid input strings. Error values: 636 * 637 * - ``-EINVAL``: wrong region format 638 * - ``-EINVAL``: invalid character in string 639 * - ``-ERANGE``: bit number specified too large for mask 640 * - ``-EOVERFLOW``: integer overflow in the input parameters 641 */ 642 int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits) 643 { 644 struct region r; 645 long ret; 646 647 bitmap_zero(maskp, nmaskbits); 648 649 while (buf) { 650 buf = bitmap_find_region(buf); 651 if (buf == NULL) 652 return 0; 653 654 buf = bitmap_parse_region(buf, &r); 655 if (IS_ERR(buf)) 656 return PTR_ERR(buf); 657 658 ret = bitmap_check_region(&r); 659 if (ret) 660 return ret; 661 662 ret = bitmap_set_region(&r, maskp, nmaskbits); 663 if (ret) 664 return ret; 665 } 666 667 return 0; 668 } 669 EXPORT_SYMBOL(bitmap_parselist); 670 671 672 /** 673 * bitmap_parselist_user() 674 * 675 * @ubuf: pointer to user buffer containing string. 676 * @ulen: buffer size in bytes. If string is smaller than this 677 * then it must be terminated with a \0. 678 * @maskp: pointer to bitmap array that will contain result. 679 * @nmaskbits: size of bitmap, in bits. 680 * 681 * Wrapper for bitmap_parselist(), providing it with user buffer. 682 */ 683 int bitmap_parselist_user(const char __user *ubuf, 684 unsigned int ulen, unsigned long *maskp, 685 int nmaskbits) 686 { 687 char *buf; 688 int ret; 689 690 buf = memdup_user_nul(ubuf, ulen); 691 if (IS_ERR(buf)) 692 return PTR_ERR(buf); 693 694 ret = bitmap_parselist(buf, maskp, nmaskbits); 695 696 kfree(buf); 697 return ret; 698 } 699 EXPORT_SYMBOL(bitmap_parselist_user); 700 701 702 #ifdef CONFIG_NUMA 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 < @nbits) 707 * @nbits: number of valid bit positions in @buf 708 * 709 * Map the bit at position @pos in @buf (of length @nbits) 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 -1. 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 */ 721 static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) 722 { 723 if (pos >= nbits || !test_bit(pos, buf)) 724 return -1; 725 726 return __bitmap_weight(buf, pos); 727 } 728 729 /** 730 * bitmap_ord_to_pos - find position of n-th set bit in bitmap 731 * @buf: pointer to bitmap 732 * @ord: ordinal bit position (n-th set bit, n >= 0) 733 * @nbits: number of valid bit positions in @buf 734 * 735 * Map the ordinal offset of bit @ord in @buf to its position in @buf. 736 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord 737 * >= weight(buf), returns @nbits. 738 * 739 * If for example, just bits 4 through 7 are set in @buf, then @ord 740 * values 0 through 3 will get mapped to 4 through 7, respectively, 741 * and all other @ord values returns @nbits. When @ord value 3 742 * gets mapped to (returns) @pos value 7 in this example, that means 743 * that the 3rd set bit (starting with 0th) is at position 7 in @buf. 744 * 745 * The bit positions 0 through @nbits-1 are valid positions in @buf. 746 */ 747 unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) 748 { 749 unsigned int pos; 750 751 for (pos = find_first_bit(buf, nbits); 752 pos < nbits && ord; 753 pos = find_next_bit(buf, nbits, pos + 1)) 754 ord--; 755 756 return pos; 757 } 758 759 /** 760 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap 761 * @dst: remapped result 762 * @src: subset to be remapped 763 * @old: defines domain of map 764 * @new: defines range of map 765 * @nbits: number of bits in each of these bitmaps 766 * 767 * Let @old and @new define a mapping of bit positions, such that 768 * whatever position is held by the n-th set bit in @old is mapped 769 * to the n-th set bit in @new. In the more general case, allowing 770 * for the possibility that the weight 'w' of @new is less than the 771 * weight of @old, map the position of the n-th set bit in @old to 772 * the position of the m-th set bit in @new, where m == n % w. 773 * 774 * If either of the @old and @new bitmaps are empty, or if @src and 775 * @dst point to the same location, then this routine copies @src 776 * to @dst. 777 * 778 * The positions of unset bits in @old are mapped to themselves 779 * (the identify map). 780 * 781 * Apply the above specified mapping to @src, placing the result in 782 * @dst, clearing any bits previously set in @dst. 783 * 784 * For example, lets say that @old has bits 4 through 7 set, and 785 * @new has bits 12 through 15 set. This defines the mapping of bit 786 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 787 * bit positions unchanged. So if say @src comes into this routine 788 * with bits 1, 5 and 7 set, then @dst should leave with bits 1, 789 * 13 and 15 set. 790 */ 791 void bitmap_remap(unsigned long *dst, const unsigned long *src, 792 const unsigned long *old, const unsigned long *new, 793 unsigned int nbits) 794 { 795 unsigned int oldbit, w; 796 797 if (dst == src) /* following doesn't handle inplace remaps */ 798 return; 799 bitmap_zero(dst, nbits); 800 801 w = bitmap_weight(new, nbits); 802 for_each_set_bit(oldbit, src, nbits) { 803 int n = bitmap_pos_to_ord(old, oldbit, nbits); 804 805 if (n < 0 || w == 0) 806 set_bit(oldbit, dst); /* identity map */ 807 else 808 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); 809 } 810 } 811 812 /** 813 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit 814 * @oldbit: bit position to be mapped 815 * @old: defines domain of map 816 * @new: defines range of map 817 * @bits: number of bits in each of these bitmaps 818 * 819 * Let @old and @new define a mapping of bit positions, such that 820 * whatever position is held by the n-th set bit in @old is mapped 821 * to the n-th set bit in @new. In the more general case, allowing 822 * for the possibility that the weight 'w' of @new is less than the 823 * weight of @old, map the position of the n-th set bit in @old to 824 * the position of the m-th set bit in @new, where m == n % w. 825 * 826 * The positions of unset bits in @old are mapped to themselves 827 * (the identify map). 828 * 829 * Apply the above specified mapping to bit position @oldbit, returning 830 * the new bit position. 831 * 832 * For example, lets say that @old has bits 4 through 7 set, and 833 * @new has bits 12 through 15 set. This defines the mapping of bit 834 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 835 * bit positions unchanged. So if say @oldbit is 5, then this routine 836 * returns 13. 837 */ 838 int bitmap_bitremap(int oldbit, const unsigned long *old, 839 const unsigned long *new, int bits) 840 { 841 int w = bitmap_weight(new, bits); 842 int n = bitmap_pos_to_ord(old, oldbit, bits); 843 if (n < 0 || w == 0) 844 return oldbit; 845 else 846 return bitmap_ord_to_pos(new, n % w, bits); 847 } 848 849 /** 850 * bitmap_onto - translate one bitmap relative to another 851 * @dst: resulting translated bitmap 852 * @orig: original untranslated bitmap 853 * @relmap: bitmap relative to which translated 854 * @bits: number of bits in each of these bitmaps 855 * 856 * Set the n-th bit of @dst iff there exists some m such that the 857 * n-th bit of @relmap is set, the m-th bit of @orig is set, and 858 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. 859 * (If you understood the previous sentence the first time your 860 * read it, you're overqualified for your current job.) 861 * 862 * In other words, @orig is mapped onto (surjectively) @dst, 863 * using the map { <n, m> | the n-th bit of @relmap is the 864 * m-th set bit of @relmap }. 865 * 866 * Any set bits in @orig above bit number W, where W is the 867 * weight of (number of set bits in) @relmap are mapped nowhere. 868 * In particular, if for all bits m set in @orig, m >= W, then 869 * @dst will end up empty. In situations where the possibility 870 * of such an empty result is not desired, one way to avoid it is 871 * to use the bitmap_fold() operator, below, to first fold the 872 * @orig bitmap over itself so that all its set bits x are in the 873 * range 0 <= x < W. The bitmap_fold() operator does this by 874 * setting the bit (m % W) in @dst, for each bit (m) set in @orig. 875 * 876 * Example [1] for bitmap_onto(): 877 * Let's say @relmap has bits 30-39 set, and @orig has bits 878 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, 879 * @dst will have bits 31, 33, 35, 37 and 39 set. 880 * 881 * When bit 0 is set in @orig, it means turn on the bit in 882 * @dst corresponding to whatever is the first bit (if any) 883 * that is turned on in @relmap. Since bit 0 was off in the 884 * above example, we leave off that bit (bit 30) in @dst. 885 * 886 * When bit 1 is set in @orig (as in the above example), it 887 * means turn on the bit in @dst corresponding to whatever 888 * is the second bit that is turned on in @relmap. The second 889 * bit in @relmap that was turned on in the above example was 890 * bit 31, so we turned on bit 31 in @dst. 891 * 892 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, 893 * because they were the 4th, 6th, 8th and 10th set bits 894 * set in @relmap, and the 4th, 6th, 8th and 10th bits of 895 * @orig (i.e. bits 3, 5, 7 and 9) were also set. 896 * 897 * When bit 11 is set in @orig, it means turn on the bit in 898 * @dst corresponding to whatever is the twelfth bit that is 899 * turned on in @relmap. In the above example, there were 900 * only ten bits turned on in @relmap (30..39), so that bit 901 * 11 was set in @orig had no affect on @dst. 902 * 903 * Example [2] for bitmap_fold() + bitmap_onto(): 904 * Let's say @relmap has these ten bits set:: 905 * 906 * 40 41 42 43 45 48 53 61 74 95 907 * 908 * (for the curious, that's 40 plus the first ten terms of the 909 * Fibonacci sequence.) 910 * 911 * Further lets say we use the following code, invoking 912 * bitmap_fold() then bitmap_onto, as suggested above to 913 * avoid the possibility of an empty @dst result:: 914 * 915 * unsigned long *tmp; // a temporary bitmap's bits 916 * 917 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); 918 * bitmap_onto(dst, tmp, relmap, bits); 919 * 920 * Then this table shows what various values of @dst would be, for 921 * various @orig's. I list the zero-based positions of each set bit. 922 * The tmp column shows the intermediate result, as computed by 923 * using bitmap_fold() to fold the @orig bitmap modulo ten 924 * (the weight of @relmap): 925 * 926 * =============== ============== ================= 927 * @orig tmp @dst 928 * 0 0 40 929 * 1 1 41 930 * 9 9 95 931 * 10 0 40 [#f1]_ 932 * 1 3 5 7 1 3 5 7 41 43 48 61 933 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 934 * 0 9 18 27 0 9 8 7 40 61 74 95 935 * 0 10 20 30 0 40 936 * 0 11 22 33 0 1 2 3 40 41 42 43 937 * 0 12 24 36 0 2 4 6 40 42 45 53 938 * 78 102 211 1 2 8 41 42 74 [#f1]_ 939 * =============== ============== ================= 940 * 941 * .. [#f1] 942 * 943 * For these marked lines, if we hadn't first done bitmap_fold() 944 * into tmp, then the @dst result would have been empty. 945 * 946 * If either of @orig or @relmap is empty (no set bits), then @dst 947 * will be returned empty. 948 * 949 * If (as explained above) the only set bits in @orig are in positions 950 * m where m >= W, (where W is the weight of @relmap) then @dst will 951 * once again be returned empty. 952 * 953 * All bits in @dst not set by the above rule are cleared. 954 */ 955 void bitmap_onto(unsigned long *dst, const unsigned long *orig, 956 const unsigned long *relmap, unsigned int bits) 957 { 958 unsigned int n, m; /* same meaning as in above comment */ 959 960 if (dst == orig) /* following doesn't handle inplace mappings */ 961 return; 962 bitmap_zero(dst, bits); 963 964 /* 965 * The following code is a more efficient, but less 966 * obvious, equivalent to the loop: 967 * for (m = 0; m < bitmap_weight(relmap, bits); m++) { 968 * n = bitmap_ord_to_pos(orig, m, bits); 969 * if (test_bit(m, orig)) 970 * set_bit(n, dst); 971 * } 972 */ 973 974 m = 0; 975 for_each_set_bit(n, relmap, bits) { 976 /* m == bitmap_pos_to_ord(relmap, n, bits) */ 977 if (test_bit(m, orig)) 978 set_bit(n, dst); 979 m++; 980 } 981 } 982 983 /** 984 * bitmap_fold - fold larger bitmap into smaller, modulo specified size 985 * @dst: resulting smaller bitmap 986 * @orig: original larger bitmap 987 * @sz: specified size 988 * @nbits: number of bits in each of these bitmaps 989 * 990 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. 991 * Clear all other bits in @dst. See further the comment and 992 * Example [2] for bitmap_onto() for why and how to use this. 993 */ 994 void bitmap_fold(unsigned long *dst, const unsigned long *orig, 995 unsigned int sz, unsigned int nbits) 996 { 997 unsigned int oldbit; 998 999 if (dst == orig) /* following doesn't handle inplace mappings */ 1000 return; 1001 bitmap_zero(dst, nbits); 1002 1003 for_each_set_bit(oldbit, orig, nbits) 1004 set_bit(oldbit % sz, dst); 1005 } 1006 #endif /* CONFIG_NUMA */ 1007 1008 /* 1009 * Common code for bitmap_*_region() routines. 1010 * bitmap: array of unsigned longs corresponding to the bitmap 1011 * pos: the beginning of the region 1012 * order: region size (log base 2 of number of bits) 1013 * reg_op: operation(s) to perform on that region of bitmap 1014 * 1015 * Can set, verify and/or release a region of bits in a bitmap, 1016 * depending on which combination of REG_OP_* flag bits is set. 1017 * 1018 * A region of a bitmap is a sequence of bits in the bitmap, of 1019 * some size '1 << order' (a power of two), aligned to that same 1020 * '1 << order' power of two. 1021 * 1022 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). 1023 * Returns 0 in all other cases and reg_ops. 1024 */ 1025 1026 enum { 1027 REG_OP_ISFREE, /* true if region is all zero bits */ 1028 REG_OP_ALLOC, /* set all bits in region */ 1029 REG_OP_RELEASE, /* clear all bits in region */ 1030 }; 1031 1032 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op) 1033 { 1034 int nbits_reg; /* number of bits in region */ 1035 int index; /* index first long of region in bitmap */ 1036 int offset; /* bit offset region in bitmap[index] */ 1037 int nlongs_reg; /* num longs spanned by region in bitmap */ 1038 int nbitsinlong; /* num bits of region in each spanned long */ 1039 unsigned long mask; /* bitmask for one long of region */ 1040 int i; /* scans bitmap by longs */ 1041 int ret = 0; /* return value */ 1042 1043 /* 1044 * Either nlongs_reg == 1 (for small orders that fit in one long) 1045 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) 1046 */ 1047 nbits_reg = 1 << order; 1048 index = pos / BITS_PER_LONG; 1049 offset = pos - (index * BITS_PER_LONG); 1050 nlongs_reg = BITS_TO_LONGS(nbits_reg); 1051 nbitsinlong = min(nbits_reg, BITS_PER_LONG); 1052 1053 /* 1054 * Can't do "mask = (1UL << nbitsinlong) - 1", as that 1055 * overflows if nbitsinlong == BITS_PER_LONG. 1056 */ 1057 mask = (1UL << (nbitsinlong - 1)); 1058 mask += mask - 1; 1059 mask <<= offset; 1060 1061 switch (reg_op) { 1062 case REG_OP_ISFREE: 1063 for (i = 0; i < nlongs_reg; i++) { 1064 if (bitmap[index + i] & mask) 1065 goto done; 1066 } 1067 ret = 1; /* all bits in region free (zero) */ 1068 break; 1069 1070 case REG_OP_ALLOC: 1071 for (i = 0; i < nlongs_reg; i++) 1072 bitmap[index + i] |= mask; 1073 break; 1074 1075 case REG_OP_RELEASE: 1076 for (i = 0; i < nlongs_reg; i++) 1077 bitmap[index + i] &= ~mask; 1078 break; 1079 } 1080 done: 1081 return ret; 1082 } 1083 1084 /** 1085 * bitmap_find_free_region - find a contiguous aligned mem region 1086 * @bitmap: array of unsigned longs corresponding to the bitmap 1087 * @bits: number of bits in the bitmap 1088 * @order: region size (log base 2 of number of bits) to find 1089 * 1090 * Find a region of free (zero) bits in a @bitmap of @bits bits and 1091 * allocate them (set them to one). Only consider regions of length 1092 * a power (@order) of two, aligned to that power of two, which 1093 * makes the search algorithm much faster. 1094 * 1095 * Return the bit offset in bitmap of the allocated region, 1096 * or -errno on failure. 1097 */ 1098 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) 1099 { 1100 unsigned int pos, end; /* scans bitmap by regions of size order */ 1101 1102 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) { 1103 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1104 continue; 1105 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1106 return pos; 1107 } 1108 return -ENOMEM; 1109 } 1110 EXPORT_SYMBOL(bitmap_find_free_region); 1111 1112 /** 1113 * bitmap_release_region - release allocated bitmap region 1114 * @bitmap: array of unsigned longs corresponding to the bitmap 1115 * @pos: beginning of bit region to release 1116 * @order: region size (log base 2 of number of bits) to release 1117 * 1118 * This is the complement to __bitmap_find_free_region() and releases 1119 * the found region (by clearing it in the bitmap). 1120 * 1121 * No return value. 1122 */ 1123 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 1124 { 1125 __reg_op(bitmap, pos, order, REG_OP_RELEASE); 1126 } 1127 EXPORT_SYMBOL(bitmap_release_region); 1128 1129 /** 1130 * bitmap_allocate_region - allocate bitmap region 1131 * @bitmap: array of unsigned longs corresponding to the bitmap 1132 * @pos: beginning of bit region to allocate 1133 * @order: region size (log base 2 of number of bits) to allocate 1134 * 1135 * Allocate (set bits in) a specified region of a bitmap. 1136 * 1137 * Return 0 on success, or %-EBUSY if specified region wasn't 1138 * free (not all bits were zero). 1139 */ 1140 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 1141 { 1142 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1143 return -EBUSY; 1144 return __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1145 } 1146 EXPORT_SYMBOL(bitmap_allocate_region); 1147 1148 /** 1149 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. 1150 * @dst: destination buffer 1151 * @src: bitmap to copy 1152 * @nbits: number of bits in the bitmap 1153 * 1154 * Require nbits % BITS_PER_LONG == 0. 1155 */ 1156 #ifdef __BIG_ENDIAN 1157 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits) 1158 { 1159 unsigned int i; 1160 1161 for (i = 0; i < nbits/BITS_PER_LONG; i++) { 1162 if (BITS_PER_LONG == 64) 1163 dst[i] = cpu_to_le64(src[i]); 1164 else 1165 dst[i] = cpu_to_le32(src[i]); 1166 } 1167 } 1168 EXPORT_SYMBOL(bitmap_copy_le); 1169 #endif 1170 1171 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags) 1172 { 1173 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long), 1174 flags); 1175 } 1176 EXPORT_SYMBOL(bitmap_alloc); 1177 1178 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags) 1179 { 1180 return bitmap_alloc(nbits, flags | __GFP_ZERO); 1181 } 1182 EXPORT_SYMBOL(bitmap_zalloc); 1183 1184 void bitmap_free(const unsigned long *bitmap) 1185 { 1186 kfree(bitmap); 1187 } 1188 EXPORT_SYMBOL(bitmap_free); 1189 1190 #if BITS_PER_LONG == 64 1191 /** 1192 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap 1193 * @bitmap: array of unsigned longs, the destination bitmap 1194 * @buf: array of u32 (in host byte order), the source bitmap 1195 * @nbits: number of bits in @bitmap 1196 */ 1197 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits) 1198 { 1199 unsigned int i, halfwords; 1200 1201 halfwords = DIV_ROUND_UP(nbits, 32); 1202 for (i = 0; i < halfwords; i++) { 1203 bitmap[i/2] = (unsigned long) buf[i]; 1204 if (++i < halfwords) 1205 bitmap[i/2] |= ((unsigned long) buf[i]) << 32; 1206 } 1207 1208 /* Clear tail bits in last word beyond nbits. */ 1209 if (nbits % BITS_PER_LONG) 1210 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits); 1211 } 1212 EXPORT_SYMBOL(bitmap_from_arr32); 1213 1214 /** 1215 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits 1216 * @buf: array of u32 (in host byte order), the dest bitmap 1217 * @bitmap: array of unsigned longs, the source bitmap 1218 * @nbits: number of bits in @bitmap 1219 */ 1220 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits) 1221 { 1222 unsigned int i, halfwords; 1223 1224 halfwords = DIV_ROUND_UP(nbits, 32); 1225 for (i = 0; i < halfwords; i++) { 1226 buf[i] = (u32) (bitmap[i/2] & UINT_MAX); 1227 if (++i < halfwords) 1228 buf[i] = (u32) (bitmap[i/2] >> 32); 1229 } 1230 1231 /* Clear tail bits in last element of array beyond nbits. */ 1232 if (nbits % BITS_PER_LONG) 1233 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31)); 1234 } 1235 EXPORT_SYMBOL(bitmap_to_arr32); 1236 1237 #endif 1238