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 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 /** 172 * bitmap_cut() - remove bit region from bitmap and right shift remaining bits 173 * @dst: destination bitmap, might overlap with src 174 * @src: source bitmap 175 * @first: start bit of region to be removed 176 * @cut: number of bits to remove 177 * @nbits: bitmap size, in bits 178 * 179 * Set the n-th bit of @dst iff the n-th bit of @src is set and 180 * n is less than @first, or the m-th bit of @src is set for any 181 * m such that @first <= n < nbits, and m = n + @cut. 182 * 183 * In pictures, example for a big-endian 32-bit architecture: 184 * 185 * The @src bitmap is:: 186 * 187 * 31 63 188 * | | 189 * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101 190 * | | | | 191 * 16 14 0 32 192 * 193 * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is:: 194 * 195 * 31 63 196 * | | 197 * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010 198 * | | | 199 * 14 (bit 17 0 32 200 * from @src) 201 * 202 * Note that @dst and @src might overlap partially or entirely. 203 * 204 * This is implemented in the obvious way, with a shift and carry 205 * step for each moved bit. Optimisation is left as an exercise 206 * for the compiler. 207 */ 208 void bitmap_cut(unsigned long *dst, const unsigned long *src, 209 unsigned int first, unsigned int cut, unsigned int nbits) 210 { 211 unsigned int len = BITS_TO_LONGS(nbits); 212 unsigned long keep = 0, carry; 213 int i; 214 215 if (first % BITS_PER_LONG) { 216 keep = src[first / BITS_PER_LONG] & 217 (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG)); 218 } 219 220 memmove(dst, src, len * sizeof(*dst)); 221 222 while (cut--) { 223 for (i = first / BITS_PER_LONG; i < len; i++) { 224 if (i < len - 1) 225 carry = dst[i + 1] & 1UL; 226 else 227 carry = 0; 228 229 dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1)); 230 } 231 } 232 233 dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG); 234 dst[first / BITS_PER_LONG] |= keep; 235 } 236 EXPORT_SYMBOL(bitmap_cut); 237 238 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, 239 const unsigned long *bitmap2, unsigned int bits) 240 { 241 unsigned int k; 242 unsigned int lim = bits/BITS_PER_LONG; 243 unsigned long result = 0; 244 245 for (k = 0; k < lim; k++) 246 result |= (dst[k] = bitmap1[k] & bitmap2[k]); 247 if (bits % BITS_PER_LONG) 248 result |= (dst[k] = bitmap1[k] & bitmap2[k] & 249 BITMAP_LAST_WORD_MASK(bits)); 250 return result != 0; 251 } 252 EXPORT_SYMBOL(__bitmap_and); 253 254 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, 255 const unsigned long *bitmap2, unsigned int bits) 256 { 257 unsigned int k; 258 unsigned int nr = BITS_TO_LONGS(bits); 259 260 for (k = 0; k < nr; k++) 261 dst[k] = bitmap1[k] | bitmap2[k]; 262 } 263 EXPORT_SYMBOL(__bitmap_or); 264 265 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, 266 const unsigned long *bitmap2, unsigned int bits) 267 { 268 unsigned int k; 269 unsigned int nr = BITS_TO_LONGS(bits); 270 271 for (k = 0; k < nr; k++) 272 dst[k] = bitmap1[k] ^ bitmap2[k]; 273 } 274 EXPORT_SYMBOL(__bitmap_xor); 275 276 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, 277 const unsigned long *bitmap2, unsigned int bits) 278 { 279 unsigned int k; 280 unsigned int lim = bits/BITS_PER_LONG; 281 unsigned long result = 0; 282 283 for (k = 0; k < lim; k++) 284 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); 285 if (bits % BITS_PER_LONG) 286 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & 287 BITMAP_LAST_WORD_MASK(bits)); 288 return result != 0; 289 } 290 EXPORT_SYMBOL(__bitmap_andnot); 291 292 void __bitmap_replace(unsigned long *dst, 293 const unsigned long *old, const unsigned long *new, 294 const unsigned long *mask, unsigned int nbits) 295 { 296 unsigned int k; 297 unsigned int nr = BITS_TO_LONGS(nbits); 298 299 for (k = 0; k < nr; k++) 300 dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]); 301 } 302 EXPORT_SYMBOL(__bitmap_replace); 303 304 int __bitmap_intersects(const unsigned long *bitmap1, 305 const unsigned long *bitmap2, unsigned int bits) 306 { 307 unsigned int k, lim = bits/BITS_PER_LONG; 308 for (k = 0; k < lim; ++k) 309 if (bitmap1[k] & bitmap2[k]) 310 return 1; 311 312 if (bits % BITS_PER_LONG) 313 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 314 return 1; 315 return 0; 316 } 317 EXPORT_SYMBOL(__bitmap_intersects); 318 319 int __bitmap_subset(const unsigned long *bitmap1, 320 const unsigned long *bitmap2, unsigned int bits) 321 { 322 unsigned int k, lim = bits/BITS_PER_LONG; 323 for (k = 0; k < lim; ++k) 324 if (bitmap1[k] & ~bitmap2[k]) 325 return 0; 326 327 if (bits % BITS_PER_LONG) 328 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 329 return 0; 330 return 1; 331 } 332 EXPORT_SYMBOL(__bitmap_subset); 333 334 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) 335 { 336 unsigned int k, lim = bits/BITS_PER_LONG; 337 int w = 0; 338 339 for (k = 0; k < lim; k++) 340 w += hweight_long(bitmap[k]); 341 342 if (bits % BITS_PER_LONG) 343 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); 344 345 return w; 346 } 347 EXPORT_SYMBOL(__bitmap_weight); 348 349 void __bitmap_set(unsigned long *map, unsigned int start, int len) 350 { 351 unsigned long *p = map + BIT_WORD(start); 352 const unsigned int size = start + len; 353 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); 354 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); 355 356 while (len - bits_to_set >= 0) { 357 *p |= mask_to_set; 358 len -= bits_to_set; 359 bits_to_set = BITS_PER_LONG; 360 mask_to_set = ~0UL; 361 p++; 362 } 363 if (len) { 364 mask_to_set &= BITMAP_LAST_WORD_MASK(size); 365 *p |= mask_to_set; 366 } 367 } 368 EXPORT_SYMBOL(__bitmap_set); 369 370 void __bitmap_clear(unsigned long *map, unsigned int start, int len) 371 { 372 unsigned long *p = map + BIT_WORD(start); 373 const unsigned int size = start + len; 374 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); 375 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); 376 377 while (len - bits_to_clear >= 0) { 378 *p &= ~mask_to_clear; 379 len -= bits_to_clear; 380 bits_to_clear = BITS_PER_LONG; 381 mask_to_clear = ~0UL; 382 p++; 383 } 384 if (len) { 385 mask_to_clear &= BITMAP_LAST_WORD_MASK(size); 386 *p &= ~mask_to_clear; 387 } 388 } 389 EXPORT_SYMBOL(__bitmap_clear); 390 391 /** 392 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area 393 * @map: The address to base the search on 394 * @size: The bitmap size in bits 395 * @start: The bitnumber to start searching at 396 * @nr: The number of zeroed bits we're looking for 397 * @align_mask: Alignment mask for zero area 398 * @align_offset: Alignment offset for zero area. 399 * 400 * The @align_mask should be one less than a power of 2; the effect is that 401 * the bit offset of all zero areas this function finds plus @align_offset 402 * is multiple of that power of 2. 403 */ 404 unsigned long bitmap_find_next_zero_area_off(unsigned long *map, 405 unsigned long size, 406 unsigned long start, 407 unsigned int nr, 408 unsigned long align_mask, 409 unsigned long align_offset) 410 { 411 unsigned long index, end, i; 412 again: 413 index = find_next_zero_bit(map, size, start); 414 415 /* Align allocation */ 416 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset; 417 418 end = index + nr; 419 if (end > size) 420 return end; 421 i = find_next_bit(map, end, index); 422 if (i < end) { 423 start = i + 1; 424 goto again; 425 } 426 return index; 427 } 428 EXPORT_SYMBOL(bitmap_find_next_zero_area_off); 429 430 /* 431 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers, 432 * second version by Paul Jackson, third by Joe Korty. 433 */ 434 435 /** 436 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap 437 * 438 * @ubuf: pointer to user buffer containing string. 439 * @ulen: buffer size in bytes. If string is smaller than this 440 * then it must be terminated with a \0. 441 * @maskp: pointer to bitmap array that will contain result. 442 * @nmaskbits: size of bitmap, in bits. 443 */ 444 int bitmap_parse_user(const char __user *ubuf, 445 unsigned int ulen, unsigned long *maskp, 446 int nmaskbits) 447 { 448 char *buf; 449 int ret; 450 451 buf = memdup_user_nul(ubuf, ulen); 452 if (IS_ERR(buf)) 453 return PTR_ERR(buf); 454 455 ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits); 456 457 kfree(buf); 458 return ret; 459 } 460 EXPORT_SYMBOL(bitmap_parse_user); 461 462 /** 463 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string 464 * @list: indicates whether the bitmap must be list 465 * @buf: page aligned buffer into which string is placed 466 * @maskp: pointer to bitmap to convert 467 * @nmaskbits: size of bitmap, in bits 468 * 469 * Output format is a comma-separated list of decimal numbers and 470 * ranges if list is specified or hex digits grouped into comma-separated 471 * sets of 8 digits/set. Returns the number of characters written to buf. 472 * 473 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned 474 * area and that sufficient storage remains at @buf to accommodate the 475 * bitmap_print_to_pagebuf() output. Returns the number of characters 476 * actually printed to @buf, excluding terminating '\0'. 477 */ 478 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, 479 int nmaskbits) 480 { 481 ptrdiff_t len = PAGE_SIZE - offset_in_page(buf); 482 483 return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : 484 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); 485 } 486 EXPORT_SYMBOL(bitmap_print_to_pagebuf); 487 488 /* 489 * Region 9-38:4/10 describes the following bitmap structure: 490 * 0 9 12 18 38 491 * .........****......****......****...... 492 * ^ ^ ^ ^ 493 * start off group_len end 494 */ 495 struct region { 496 unsigned int start; 497 unsigned int off; 498 unsigned int group_len; 499 unsigned int end; 500 }; 501 502 static int bitmap_set_region(const struct region *r, 503 unsigned long *bitmap, int nbits) 504 { 505 unsigned int start; 506 507 if (r->end >= nbits) 508 return -ERANGE; 509 510 for (start = r->start; start <= r->end; start += r->group_len) 511 bitmap_set(bitmap, start, min(r->end - start + 1, r->off)); 512 513 return 0; 514 } 515 516 static int bitmap_check_region(const struct region *r) 517 { 518 if (r->start > r->end || r->group_len == 0 || r->off > r->group_len) 519 return -EINVAL; 520 521 return 0; 522 } 523 524 static const char *bitmap_getnum(const char *str, unsigned int *num) 525 { 526 unsigned long long n; 527 unsigned int len; 528 529 len = _parse_integer(str, 10, &n); 530 if (!len) 531 return ERR_PTR(-EINVAL); 532 if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n) 533 return ERR_PTR(-EOVERFLOW); 534 535 *num = n; 536 return str + len; 537 } 538 539 static inline bool end_of_str(char c) 540 { 541 return c == '\0' || c == '\n'; 542 } 543 544 static inline bool __end_of_region(char c) 545 { 546 return isspace(c) || c == ','; 547 } 548 549 static inline bool end_of_region(char c) 550 { 551 return __end_of_region(c) || end_of_str(c); 552 } 553 554 /* 555 * The format allows commas and whitespaces at the beginning 556 * of the region. 557 */ 558 static const char *bitmap_find_region(const char *str) 559 { 560 while (__end_of_region(*str)) 561 str++; 562 563 return end_of_str(*str) ? NULL : str; 564 } 565 566 static const char *bitmap_find_region_reverse(const char *start, const char *end) 567 { 568 while (start <= end && __end_of_region(*end)) 569 end--; 570 571 return end; 572 } 573 574 static const char *bitmap_parse_region(const char *str, struct region *r) 575 { 576 str = bitmap_getnum(str, &r->start); 577 if (IS_ERR(str)) 578 return str; 579 580 if (end_of_region(*str)) 581 goto no_end; 582 583 if (*str != '-') 584 return ERR_PTR(-EINVAL); 585 586 str = bitmap_getnum(str + 1, &r->end); 587 if (IS_ERR(str)) 588 return str; 589 590 if (end_of_region(*str)) 591 goto no_pattern; 592 593 if (*str != ':') 594 return ERR_PTR(-EINVAL); 595 596 str = bitmap_getnum(str + 1, &r->off); 597 if (IS_ERR(str)) 598 return str; 599 600 if (*str != '/') 601 return ERR_PTR(-EINVAL); 602 603 return bitmap_getnum(str + 1, &r->group_len); 604 605 no_end: 606 r->end = r->start; 607 no_pattern: 608 r->off = r->end + 1; 609 r->group_len = r->end + 1; 610 611 return end_of_str(*str) ? NULL : str; 612 } 613 614 /** 615 * bitmap_parselist - convert list format ASCII string to bitmap 616 * @buf: read user string from this buffer; must be terminated 617 * with a \0 or \n. 618 * @maskp: write resulting mask here 619 * @nmaskbits: number of bits in mask to be written 620 * 621 * Input format is a comma-separated list of decimal numbers and 622 * ranges. Consecutively set bits are shown as two hyphen-separated 623 * decimal numbers, the smallest and largest bit numbers set in 624 * the range. 625 * Optionally each range can be postfixed to denote that only parts of it 626 * should be set. The range will divided to groups of specific size. 627 * From each group will be used only defined amount of bits. 628 * Syntax: range:used_size/group_size 629 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769 630 * 631 * Returns: 0 on success, -errno on invalid input strings. Error values: 632 * 633 * - ``-EINVAL``: wrong region format 634 * - ``-EINVAL``: invalid character in string 635 * - ``-ERANGE``: bit number specified too large for mask 636 * - ``-EOVERFLOW``: integer overflow in the input parameters 637 */ 638 int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits) 639 { 640 struct region r; 641 long ret; 642 643 bitmap_zero(maskp, nmaskbits); 644 645 while (buf) { 646 buf = bitmap_find_region(buf); 647 if (buf == NULL) 648 return 0; 649 650 buf = bitmap_parse_region(buf, &r); 651 if (IS_ERR(buf)) 652 return PTR_ERR(buf); 653 654 ret = bitmap_check_region(&r); 655 if (ret) 656 return ret; 657 658 ret = bitmap_set_region(&r, maskp, nmaskbits); 659 if (ret) 660 return ret; 661 } 662 663 return 0; 664 } 665 EXPORT_SYMBOL(bitmap_parselist); 666 667 668 /** 669 * bitmap_parselist_user() 670 * 671 * @ubuf: pointer to user buffer containing string. 672 * @ulen: buffer size in bytes. If string is smaller than this 673 * then it must be terminated with a \0. 674 * @maskp: pointer to bitmap array that will contain result. 675 * @nmaskbits: size of bitmap, in bits. 676 * 677 * Wrapper for bitmap_parselist(), providing it with user buffer. 678 */ 679 int bitmap_parselist_user(const char __user *ubuf, 680 unsigned int ulen, unsigned long *maskp, 681 int nmaskbits) 682 { 683 char *buf; 684 int ret; 685 686 buf = memdup_user_nul(ubuf, ulen); 687 if (IS_ERR(buf)) 688 return PTR_ERR(buf); 689 690 ret = bitmap_parselist(buf, maskp, nmaskbits); 691 692 kfree(buf); 693 return ret; 694 } 695 EXPORT_SYMBOL(bitmap_parselist_user); 696 697 static const char *bitmap_get_x32_reverse(const char *start, 698 const char *end, u32 *num) 699 { 700 u32 ret = 0; 701 int c, i; 702 703 for (i = 0; i < 32; i += 4) { 704 c = hex_to_bin(*end--); 705 if (c < 0) 706 return ERR_PTR(-EINVAL); 707 708 ret |= c << i; 709 710 if (start > end || __end_of_region(*end)) 711 goto out; 712 } 713 714 if (hex_to_bin(*end--) >= 0) 715 return ERR_PTR(-EOVERFLOW); 716 out: 717 *num = ret; 718 return end; 719 } 720 721 /** 722 * bitmap_parse - convert an ASCII hex string into a bitmap. 723 * @start: pointer to buffer containing string. 724 * @buflen: buffer size in bytes. If string is smaller than this 725 * then it must be terminated with a \0 or \n. In that case, 726 * UINT_MAX may be provided instead of string length. 727 * @maskp: pointer to bitmap array that will contain result. 728 * @nmaskbits: size of bitmap, in bits. 729 * 730 * Commas group hex digits into chunks. Each chunk defines exactly 32 731 * bits of the resultant bitmask. No chunk may specify a value larger 732 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value 733 * then leading 0-bits are prepended. %-EINVAL is returned for illegal 734 * characters. Grouping such as "1,,5", ",44", "," or "" is allowed. 735 * Leading, embedded and trailing whitespace accepted. 736 */ 737 int bitmap_parse(const char *start, unsigned int buflen, 738 unsigned long *maskp, int nmaskbits) 739 { 740 const char *end = strnchrnul(start, buflen, '\n') - 1; 741 int chunks = BITS_TO_U32(nmaskbits); 742 u32 *bitmap = (u32 *)maskp; 743 int unset_bit; 744 int chunk; 745 746 for (chunk = 0; ; chunk++) { 747 end = bitmap_find_region_reverse(start, end); 748 if (start > end) 749 break; 750 751 if (!chunks--) 752 return -EOVERFLOW; 753 754 #if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN) 755 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]); 756 #else 757 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]); 758 #endif 759 if (IS_ERR(end)) 760 return PTR_ERR(end); 761 } 762 763 unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32; 764 if (unset_bit < nmaskbits) { 765 bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit); 766 return 0; 767 } 768 769 if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit) 770 return -EOVERFLOW; 771 772 return 0; 773 } 774 EXPORT_SYMBOL(bitmap_parse); 775 776 777 #ifdef CONFIG_NUMA 778 /** 779 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap 780 * @buf: pointer to a bitmap 781 * @pos: a bit position in @buf (0 <= @pos < @nbits) 782 * @nbits: number of valid bit positions in @buf 783 * 784 * Map the bit at position @pos in @buf (of length @nbits) to the 785 * ordinal of which set bit it is. If it is not set or if @pos 786 * is not a valid bit position, map to -1. 787 * 788 * If for example, just bits 4 through 7 are set in @buf, then @pos 789 * values 4 through 7 will get mapped to 0 through 3, respectively, 790 * and other @pos values will get mapped to -1. When @pos value 7 791 * gets mapped to (returns) @ord value 3 in this example, that means 792 * that bit 7 is the 3rd (starting with 0th) set bit in @buf. 793 * 794 * The bit positions 0 through @bits are valid positions in @buf. 795 */ 796 static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) 797 { 798 if (pos >= nbits || !test_bit(pos, buf)) 799 return -1; 800 801 return __bitmap_weight(buf, pos); 802 } 803 804 /** 805 * bitmap_ord_to_pos - find position of n-th set bit in bitmap 806 * @buf: pointer to bitmap 807 * @ord: ordinal bit position (n-th set bit, n >= 0) 808 * @nbits: number of valid bit positions in @buf 809 * 810 * Map the ordinal offset of bit @ord in @buf to its position in @buf. 811 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord 812 * >= weight(buf), returns @nbits. 813 * 814 * If for example, just bits 4 through 7 are set in @buf, then @ord 815 * values 0 through 3 will get mapped to 4 through 7, respectively, 816 * and all other @ord values returns @nbits. When @ord value 3 817 * gets mapped to (returns) @pos value 7 in this example, that means 818 * that the 3rd set bit (starting with 0th) is at position 7 in @buf. 819 * 820 * The bit positions 0 through @nbits-1 are valid positions in @buf. 821 */ 822 unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) 823 { 824 unsigned int pos; 825 826 for (pos = find_first_bit(buf, nbits); 827 pos < nbits && ord; 828 pos = find_next_bit(buf, nbits, pos + 1)) 829 ord--; 830 831 return pos; 832 } 833 834 /** 835 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap 836 * @dst: remapped result 837 * @src: subset to be remapped 838 * @old: defines domain of map 839 * @new: defines range of map 840 * @nbits: number of bits in each of these bitmaps 841 * 842 * Let @old and @new define a mapping of bit positions, such that 843 * whatever position is held by the n-th set bit in @old is mapped 844 * to the n-th set bit in @new. In the more general case, allowing 845 * for the possibility that the weight 'w' of @new is less than the 846 * weight of @old, map the position of the n-th set bit in @old to 847 * the position of the m-th set bit in @new, where m == n % w. 848 * 849 * If either of the @old and @new bitmaps are empty, or if @src and 850 * @dst point to the same location, then this routine copies @src 851 * to @dst. 852 * 853 * The positions of unset bits in @old are mapped to themselves 854 * (the identify map). 855 * 856 * Apply the above specified mapping to @src, placing the result in 857 * @dst, clearing any bits previously set in @dst. 858 * 859 * For example, lets say that @old has bits 4 through 7 set, and 860 * @new has bits 12 through 15 set. This defines the mapping of bit 861 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 862 * bit positions unchanged. So if say @src comes into this routine 863 * with bits 1, 5 and 7 set, then @dst should leave with bits 1, 864 * 13 and 15 set. 865 */ 866 void bitmap_remap(unsigned long *dst, const unsigned long *src, 867 const unsigned long *old, const unsigned long *new, 868 unsigned int nbits) 869 { 870 unsigned int oldbit, w; 871 872 if (dst == src) /* following doesn't handle inplace remaps */ 873 return; 874 bitmap_zero(dst, nbits); 875 876 w = bitmap_weight(new, nbits); 877 for_each_set_bit(oldbit, src, nbits) { 878 int n = bitmap_pos_to_ord(old, oldbit, nbits); 879 880 if (n < 0 || w == 0) 881 set_bit(oldbit, dst); /* identity map */ 882 else 883 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); 884 } 885 } 886 887 /** 888 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit 889 * @oldbit: bit position to be mapped 890 * @old: defines domain of map 891 * @new: defines range of map 892 * @bits: number of bits in each of these bitmaps 893 * 894 * Let @old and @new define a mapping of bit positions, such that 895 * whatever position is held by the n-th set bit in @old is mapped 896 * to the n-th set bit in @new. In the more general case, allowing 897 * for the possibility that the weight 'w' of @new is less than the 898 * weight of @old, map the position of the n-th set bit in @old to 899 * the position of the m-th set bit in @new, where m == n % w. 900 * 901 * The positions of unset bits in @old are mapped to themselves 902 * (the identify map). 903 * 904 * Apply the above specified mapping to bit position @oldbit, returning 905 * the new bit position. 906 * 907 * For example, lets say that @old has bits 4 through 7 set, and 908 * @new has bits 12 through 15 set. This defines the mapping of bit 909 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 910 * bit positions unchanged. So if say @oldbit is 5, then this routine 911 * returns 13. 912 */ 913 int bitmap_bitremap(int oldbit, const unsigned long *old, 914 const unsigned long *new, int bits) 915 { 916 int w = bitmap_weight(new, bits); 917 int n = bitmap_pos_to_ord(old, oldbit, bits); 918 if (n < 0 || w == 0) 919 return oldbit; 920 else 921 return bitmap_ord_to_pos(new, n % w, bits); 922 } 923 924 /** 925 * bitmap_onto - translate one bitmap relative to another 926 * @dst: resulting translated bitmap 927 * @orig: original untranslated bitmap 928 * @relmap: bitmap relative to which translated 929 * @bits: number of bits in each of these bitmaps 930 * 931 * Set the n-th bit of @dst iff there exists some m such that the 932 * n-th bit of @relmap is set, the m-th bit of @orig is set, and 933 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. 934 * (If you understood the previous sentence the first time your 935 * read it, you're overqualified for your current job.) 936 * 937 * In other words, @orig is mapped onto (surjectively) @dst, 938 * using the map { <n, m> | the n-th bit of @relmap is the 939 * m-th set bit of @relmap }. 940 * 941 * Any set bits in @orig above bit number W, where W is the 942 * weight of (number of set bits in) @relmap are mapped nowhere. 943 * In particular, if for all bits m set in @orig, m >= W, then 944 * @dst will end up empty. In situations where the possibility 945 * of such an empty result is not desired, one way to avoid it is 946 * to use the bitmap_fold() operator, below, to first fold the 947 * @orig bitmap over itself so that all its set bits x are in the 948 * range 0 <= x < W. The bitmap_fold() operator does this by 949 * setting the bit (m % W) in @dst, for each bit (m) set in @orig. 950 * 951 * Example [1] for bitmap_onto(): 952 * Let's say @relmap has bits 30-39 set, and @orig has bits 953 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, 954 * @dst will have bits 31, 33, 35, 37 and 39 set. 955 * 956 * When bit 0 is set in @orig, it means turn on the bit in 957 * @dst corresponding to whatever is the first bit (if any) 958 * that is turned on in @relmap. Since bit 0 was off in the 959 * above example, we leave off that bit (bit 30) in @dst. 960 * 961 * When bit 1 is set in @orig (as in the above example), it 962 * means turn on the bit in @dst corresponding to whatever 963 * is the second bit that is turned on in @relmap. The second 964 * bit in @relmap that was turned on in the above example was 965 * bit 31, so we turned on bit 31 in @dst. 966 * 967 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, 968 * because they were the 4th, 6th, 8th and 10th set bits 969 * set in @relmap, and the 4th, 6th, 8th and 10th bits of 970 * @orig (i.e. bits 3, 5, 7 and 9) were also set. 971 * 972 * When bit 11 is set in @orig, it means turn on the bit in 973 * @dst corresponding to whatever is the twelfth bit that is 974 * turned on in @relmap. In the above example, there were 975 * only ten bits turned on in @relmap (30..39), so that bit 976 * 11 was set in @orig had no affect on @dst. 977 * 978 * Example [2] for bitmap_fold() + bitmap_onto(): 979 * Let's say @relmap has these ten bits set:: 980 * 981 * 40 41 42 43 45 48 53 61 74 95 982 * 983 * (for the curious, that's 40 plus the first ten terms of the 984 * Fibonacci sequence.) 985 * 986 * Further lets say we use the following code, invoking 987 * bitmap_fold() then bitmap_onto, as suggested above to 988 * avoid the possibility of an empty @dst result:: 989 * 990 * unsigned long *tmp; // a temporary bitmap's bits 991 * 992 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); 993 * bitmap_onto(dst, tmp, relmap, bits); 994 * 995 * Then this table shows what various values of @dst would be, for 996 * various @orig's. I list the zero-based positions of each set bit. 997 * The tmp column shows the intermediate result, as computed by 998 * using bitmap_fold() to fold the @orig bitmap modulo ten 999 * (the weight of @relmap): 1000 * 1001 * =============== ============== ================= 1002 * @orig tmp @dst 1003 * 0 0 40 1004 * 1 1 41 1005 * 9 9 95 1006 * 10 0 40 [#f1]_ 1007 * 1 3 5 7 1 3 5 7 41 43 48 61 1008 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 1009 * 0 9 18 27 0 9 8 7 40 61 74 95 1010 * 0 10 20 30 0 40 1011 * 0 11 22 33 0 1 2 3 40 41 42 43 1012 * 0 12 24 36 0 2 4 6 40 42 45 53 1013 * 78 102 211 1 2 8 41 42 74 [#f1]_ 1014 * =============== ============== ================= 1015 * 1016 * .. [#f1] 1017 * 1018 * For these marked lines, if we hadn't first done bitmap_fold() 1019 * into tmp, then the @dst result would have been empty. 1020 * 1021 * If either of @orig or @relmap is empty (no set bits), then @dst 1022 * will be returned empty. 1023 * 1024 * If (as explained above) the only set bits in @orig are in positions 1025 * m where m >= W, (where W is the weight of @relmap) then @dst will 1026 * once again be returned empty. 1027 * 1028 * All bits in @dst not set by the above rule are cleared. 1029 */ 1030 void bitmap_onto(unsigned long *dst, const unsigned long *orig, 1031 const unsigned long *relmap, unsigned int bits) 1032 { 1033 unsigned int n, m; /* same meaning as in above comment */ 1034 1035 if (dst == orig) /* following doesn't handle inplace mappings */ 1036 return; 1037 bitmap_zero(dst, bits); 1038 1039 /* 1040 * The following code is a more efficient, but less 1041 * obvious, equivalent to the loop: 1042 * for (m = 0; m < bitmap_weight(relmap, bits); m++) { 1043 * n = bitmap_ord_to_pos(orig, m, bits); 1044 * if (test_bit(m, orig)) 1045 * set_bit(n, dst); 1046 * } 1047 */ 1048 1049 m = 0; 1050 for_each_set_bit(n, relmap, bits) { 1051 /* m == bitmap_pos_to_ord(relmap, n, bits) */ 1052 if (test_bit(m, orig)) 1053 set_bit(n, dst); 1054 m++; 1055 } 1056 } 1057 1058 /** 1059 * bitmap_fold - fold larger bitmap into smaller, modulo specified size 1060 * @dst: resulting smaller bitmap 1061 * @orig: original larger bitmap 1062 * @sz: specified size 1063 * @nbits: number of bits in each of these bitmaps 1064 * 1065 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. 1066 * Clear all other bits in @dst. See further the comment and 1067 * Example [2] for bitmap_onto() for why and how to use this. 1068 */ 1069 void bitmap_fold(unsigned long *dst, const unsigned long *orig, 1070 unsigned int sz, unsigned int nbits) 1071 { 1072 unsigned int oldbit; 1073 1074 if (dst == orig) /* following doesn't handle inplace mappings */ 1075 return; 1076 bitmap_zero(dst, nbits); 1077 1078 for_each_set_bit(oldbit, orig, nbits) 1079 set_bit(oldbit % sz, dst); 1080 } 1081 #endif /* CONFIG_NUMA */ 1082 1083 /* 1084 * Common code for bitmap_*_region() routines. 1085 * bitmap: array of unsigned longs corresponding to the bitmap 1086 * pos: the beginning of the region 1087 * order: region size (log base 2 of number of bits) 1088 * reg_op: operation(s) to perform on that region of bitmap 1089 * 1090 * Can set, verify and/or release a region of bits in a bitmap, 1091 * depending on which combination of REG_OP_* flag bits is set. 1092 * 1093 * A region of a bitmap is a sequence of bits in the bitmap, of 1094 * some size '1 << order' (a power of two), aligned to that same 1095 * '1 << order' power of two. 1096 * 1097 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). 1098 * Returns 0 in all other cases and reg_ops. 1099 */ 1100 1101 enum { 1102 REG_OP_ISFREE, /* true if region is all zero bits */ 1103 REG_OP_ALLOC, /* set all bits in region */ 1104 REG_OP_RELEASE, /* clear all bits in region */ 1105 }; 1106 1107 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op) 1108 { 1109 int nbits_reg; /* number of bits in region */ 1110 int index; /* index first long of region in bitmap */ 1111 int offset; /* bit offset region in bitmap[index] */ 1112 int nlongs_reg; /* num longs spanned by region in bitmap */ 1113 int nbitsinlong; /* num bits of region in each spanned long */ 1114 unsigned long mask; /* bitmask for one long of region */ 1115 int i; /* scans bitmap by longs */ 1116 int ret = 0; /* return value */ 1117 1118 /* 1119 * Either nlongs_reg == 1 (for small orders that fit in one long) 1120 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) 1121 */ 1122 nbits_reg = 1 << order; 1123 index = pos / BITS_PER_LONG; 1124 offset = pos - (index * BITS_PER_LONG); 1125 nlongs_reg = BITS_TO_LONGS(nbits_reg); 1126 nbitsinlong = min(nbits_reg, BITS_PER_LONG); 1127 1128 /* 1129 * Can't do "mask = (1UL << nbitsinlong) - 1", as that 1130 * overflows if nbitsinlong == BITS_PER_LONG. 1131 */ 1132 mask = (1UL << (nbitsinlong - 1)); 1133 mask += mask - 1; 1134 mask <<= offset; 1135 1136 switch (reg_op) { 1137 case REG_OP_ISFREE: 1138 for (i = 0; i < nlongs_reg; i++) { 1139 if (bitmap[index + i] & mask) 1140 goto done; 1141 } 1142 ret = 1; /* all bits in region free (zero) */ 1143 break; 1144 1145 case REG_OP_ALLOC: 1146 for (i = 0; i < nlongs_reg; i++) 1147 bitmap[index + i] |= mask; 1148 break; 1149 1150 case REG_OP_RELEASE: 1151 for (i = 0; i < nlongs_reg; i++) 1152 bitmap[index + i] &= ~mask; 1153 break; 1154 } 1155 done: 1156 return ret; 1157 } 1158 1159 /** 1160 * bitmap_find_free_region - find a contiguous aligned mem region 1161 * @bitmap: array of unsigned longs corresponding to the bitmap 1162 * @bits: number of bits in the bitmap 1163 * @order: region size (log base 2 of number of bits) to find 1164 * 1165 * Find a region of free (zero) bits in a @bitmap of @bits bits and 1166 * allocate them (set them to one). Only consider regions of length 1167 * a power (@order) of two, aligned to that power of two, which 1168 * makes the search algorithm much faster. 1169 * 1170 * Return the bit offset in bitmap of the allocated region, 1171 * or -errno on failure. 1172 */ 1173 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) 1174 { 1175 unsigned int pos, end; /* scans bitmap by regions of size order */ 1176 1177 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) { 1178 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1179 continue; 1180 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1181 return pos; 1182 } 1183 return -ENOMEM; 1184 } 1185 EXPORT_SYMBOL(bitmap_find_free_region); 1186 1187 /** 1188 * bitmap_release_region - release allocated bitmap region 1189 * @bitmap: array of unsigned longs corresponding to the bitmap 1190 * @pos: beginning of bit region to release 1191 * @order: region size (log base 2 of number of bits) to release 1192 * 1193 * This is the complement to __bitmap_find_free_region() and releases 1194 * the found region (by clearing it in the bitmap). 1195 * 1196 * No return value. 1197 */ 1198 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 1199 { 1200 __reg_op(bitmap, pos, order, REG_OP_RELEASE); 1201 } 1202 EXPORT_SYMBOL(bitmap_release_region); 1203 1204 /** 1205 * bitmap_allocate_region - allocate bitmap region 1206 * @bitmap: array of unsigned longs corresponding to the bitmap 1207 * @pos: beginning of bit region to allocate 1208 * @order: region size (log base 2 of number of bits) to allocate 1209 * 1210 * Allocate (set bits in) a specified region of a bitmap. 1211 * 1212 * Return 0 on success, or %-EBUSY if specified region wasn't 1213 * free (not all bits were zero). 1214 */ 1215 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 1216 { 1217 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1218 return -EBUSY; 1219 return __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1220 } 1221 EXPORT_SYMBOL(bitmap_allocate_region); 1222 1223 /** 1224 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. 1225 * @dst: destination buffer 1226 * @src: bitmap to copy 1227 * @nbits: number of bits in the bitmap 1228 * 1229 * Require nbits % BITS_PER_LONG == 0. 1230 */ 1231 #ifdef __BIG_ENDIAN 1232 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits) 1233 { 1234 unsigned int i; 1235 1236 for (i = 0; i < nbits/BITS_PER_LONG; i++) { 1237 if (BITS_PER_LONG == 64) 1238 dst[i] = cpu_to_le64(src[i]); 1239 else 1240 dst[i] = cpu_to_le32(src[i]); 1241 } 1242 } 1243 EXPORT_SYMBOL(bitmap_copy_le); 1244 #endif 1245 1246 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags) 1247 { 1248 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long), 1249 flags); 1250 } 1251 EXPORT_SYMBOL(bitmap_alloc); 1252 1253 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags) 1254 { 1255 return bitmap_alloc(nbits, flags | __GFP_ZERO); 1256 } 1257 EXPORT_SYMBOL(bitmap_zalloc); 1258 1259 void bitmap_free(const unsigned long *bitmap) 1260 { 1261 kfree(bitmap); 1262 } 1263 EXPORT_SYMBOL(bitmap_free); 1264 1265 #if BITS_PER_LONG == 64 1266 /** 1267 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap 1268 * @bitmap: array of unsigned longs, the destination bitmap 1269 * @buf: array of u32 (in host byte order), the source bitmap 1270 * @nbits: number of bits in @bitmap 1271 */ 1272 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits) 1273 { 1274 unsigned int i, halfwords; 1275 1276 halfwords = DIV_ROUND_UP(nbits, 32); 1277 for (i = 0; i < halfwords; i++) { 1278 bitmap[i/2] = (unsigned long) buf[i]; 1279 if (++i < halfwords) 1280 bitmap[i/2] |= ((unsigned long) buf[i]) << 32; 1281 } 1282 1283 /* Clear tail bits in last word beyond nbits. */ 1284 if (nbits % BITS_PER_LONG) 1285 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits); 1286 } 1287 EXPORT_SYMBOL(bitmap_from_arr32); 1288 1289 /** 1290 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits 1291 * @buf: array of u32 (in host byte order), the dest bitmap 1292 * @bitmap: array of unsigned longs, the source bitmap 1293 * @nbits: number of bits in @bitmap 1294 */ 1295 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits) 1296 { 1297 unsigned int i, halfwords; 1298 1299 halfwords = DIV_ROUND_UP(nbits, 32); 1300 for (i = 0; i < halfwords; i++) { 1301 buf[i] = (u32) (bitmap[i/2] & UINT_MAX); 1302 if (++i < halfwords) 1303 buf[i] = (u32) (bitmap[i/2] >> 32); 1304 } 1305 1306 /* Clear tail bits in last element of array beyond nbits. */ 1307 if (nbits % BITS_PER_LONG) 1308 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31)); 1309 } 1310 EXPORT_SYMBOL(bitmap_to_arr32); 1311 1312 #endif 1313