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 <linux/kernel.h> 16 #include <linux/string.h> 17 #include <linux/uaccess.h> 18 19 #include <asm/page.h> 20 21 /** 22 * DOC: bitmap introduction 23 * 24 * bitmaps provide an array of bits, implemented using an an 25 * array of unsigned longs. The number of valid bits in a 26 * given bitmap does _not_ need to be an exact multiple of 27 * BITS_PER_LONG. 28 * 29 * The possible unused bits in the last, partially used word 30 * of a bitmap are 'don't care'. The implementation makes 31 * no particular effort to keep them zero. It ensures that 32 * their value will not affect the results of any operation. 33 * The bitmap operations that return Boolean (bitmap_empty, 34 * for example) or scalar (bitmap_weight, for example) results 35 * carefully filter out these unused bits from impacting their 36 * results. 37 * 38 * These operations actually hold to a slightly stronger rule: 39 * if you don't input any bitmaps to these ops that have some 40 * unused bits set, then they won't output any set unused bits 41 * in output bitmaps. 42 * 43 * The byte ordering of bitmaps is more natural on little 44 * endian architectures. See the big-endian headers 45 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h 46 * for the best explanations of this ordering. 47 */ 48 49 int __bitmap_equal(const unsigned long *bitmap1, 50 const unsigned long *bitmap2, unsigned int bits) 51 { 52 unsigned int k, lim = bits/BITS_PER_LONG; 53 for (k = 0; k < lim; ++k) 54 if (bitmap1[k] != bitmap2[k]) 55 return 0; 56 57 if (bits % BITS_PER_LONG) 58 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 59 return 0; 60 61 return 1; 62 } 63 EXPORT_SYMBOL(__bitmap_equal); 64 65 void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits) 66 { 67 unsigned int k, lim = bits/BITS_PER_LONG; 68 for (k = 0; k < lim; ++k) 69 dst[k] = ~src[k]; 70 71 if (bits % BITS_PER_LONG) 72 dst[k] = ~src[k]; 73 } 74 EXPORT_SYMBOL(__bitmap_complement); 75 76 /** 77 * __bitmap_shift_right - logical right shift of the bits in a bitmap 78 * @dst : destination bitmap 79 * @src : source bitmap 80 * @shift : shift by this many bits 81 * @nbits : bitmap size, in bits 82 * 83 * Shifting right (dividing) means moving bits in the MS -> LS bit 84 * direction. Zeros are fed into the vacated MS positions and the 85 * LS bits shifted off the bottom are lost. 86 */ 87 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, 88 unsigned shift, unsigned nbits) 89 { 90 unsigned k, lim = BITS_TO_LONGS(nbits); 91 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; 92 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); 93 for (k = 0; off + k < lim; ++k) { 94 unsigned long upper, lower; 95 96 /* 97 * If shift is not word aligned, take lower rem bits of 98 * word above and make them the top rem bits of result. 99 */ 100 if (!rem || off + k + 1 >= lim) 101 upper = 0; 102 else { 103 upper = src[off + k + 1]; 104 if (off + k + 1 == lim - 1) 105 upper &= mask; 106 upper <<= (BITS_PER_LONG - rem); 107 } 108 lower = src[off + k]; 109 if (off + k == lim - 1) 110 lower &= mask; 111 lower >>= rem; 112 dst[k] = lower | upper; 113 } 114 if (off) 115 memset(&dst[lim - off], 0, off*sizeof(unsigned long)); 116 } 117 EXPORT_SYMBOL(__bitmap_shift_right); 118 119 120 /** 121 * __bitmap_shift_left - logical left shift of the bits in a bitmap 122 * @dst : destination bitmap 123 * @src : source bitmap 124 * @shift : shift by this many bits 125 * @nbits : bitmap size, in bits 126 * 127 * Shifting left (multiplying) means moving bits in the LS -> MS 128 * direction. Zeros are fed into the vacated LS bit positions 129 * and those MS bits shifted off the top are lost. 130 */ 131 132 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, 133 unsigned int shift, unsigned int nbits) 134 { 135 int k; 136 unsigned int lim = BITS_TO_LONGS(nbits); 137 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; 138 for (k = lim - off - 1; k >= 0; --k) { 139 unsigned long upper, lower; 140 141 /* 142 * If shift is not word aligned, take upper rem bits of 143 * word below and make them the bottom rem bits of result. 144 */ 145 if (rem && k > 0) 146 lower = src[k - 1] >> (BITS_PER_LONG - rem); 147 else 148 lower = 0; 149 upper = src[k] << rem; 150 dst[k + off] = lower | upper; 151 } 152 if (off) 153 memset(dst, 0, off*sizeof(unsigned long)); 154 } 155 EXPORT_SYMBOL(__bitmap_shift_left); 156 157 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, 158 const unsigned long *bitmap2, unsigned int bits) 159 { 160 unsigned int k; 161 unsigned int lim = bits/BITS_PER_LONG; 162 unsigned long result = 0; 163 164 for (k = 0; k < lim; k++) 165 result |= (dst[k] = bitmap1[k] & bitmap2[k]); 166 if (bits % BITS_PER_LONG) 167 result |= (dst[k] = bitmap1[k] & bitmap2[k] & 168 BITMAP_LAST_WORD_MASK(bits)); 169 return result != 0; 170 } 171 EXPORT_SYMBOL(__bitmap_and); 172 173 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, 174 const unsigned long *bitmap2, unsigned int bits) 175 { 176 unsigned int k; 177 unsigned int nr = BITS_TO_LONGS(bits); 178 179 for (k = 0; k < nr; k++) 180 dst[k] = bitmap1[k] | bitmap2[k]; 181 } 182 EXPORT_SYMBOL(__bitmap_or); 183 184 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, 185 const unsigned long *bitmap2, unsigned int bits) 186 { 187 unsigned int k; 188 unsigned int nr = BITS_TO_LONGS(bits); 189 190 for (k = 0; k < nr; k++) 191 dst[k] = bitmap1[k] ^ bitmap2[k]; 192 } 193 EXPORT_SYMBOL(__bitmap_xor); 194 195 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, 196 const unsigned long *bitmap2, unsigned int bits) 197 { 198 unsigned int k; 199 unsigned int lim = bits/BITS_PER_LONG; 200 unsigned long result = 0; 201 202 for (k = 0; k < lim; k++) 203 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); 204 if (bits % BITS_PER_LONG) 205 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & 206 BITMAP_LAST_WORD_MASK(bits)); 207 return result != 0; 208 } 209 EXPORT_SYMBOL(__bitmap_andnot); 210 211 int __bitmap_intersects(const unsigned long *bitmap1, 212 const unsigned long *bitmap2, unsigned int bits) 213 { 214 unsigned int k, lim = bits/BITS_PER_LONG; 215 for (k = 0; k < lim; ++k) 216 if (bitmap1[k] & bitmap2[k]) 217 return 1; 218 219 if (bits % BITS_PER_LONG) 220 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 221 return 1; 222 return 0; 223 } 224 EXPORT_SYMBOL(__bitmap_intersects); 225 226 int __bitmap_subset(const unsigned long *bitmap1, 227 const unsigned long *bitmap2, unsigned int bits) 228 { 229 unsigned int k, lim = bits/BITS_PER_LONG; 230 for (k = 0; k < lim; ++k) 231 if (bitmap1[k] & ~bitmap2[k]) 232 return 0; 233 234 if (bits % BITS_PER_LONG) 235 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 236 return 0; 237 return 1; 238 } 239 EXPORT_SYMBOL(__bitmap_subset); 240 241 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) 242 { 243 unsigned int k, lim = bits/BITS_PER_LONG; 244 int w = 0; 245 246 for (k = 0; k < lim; k++) 247 w += hweight_long(bitmap[k]); 248 249 if (bits % BITS_PER_LONG) 250 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); 251 252 return w; 253 } 254 EXPORT_SYMBOL(__bitmap_weight); 255 256 void __bitmap_set(unsigned long *map, unsigned int start, int len) 257 { 258 unsigned long *p = map + BIT_WORD(start); 259 const unsigned int size = start + len; 260 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); 261 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); 262 263 while (len - bits_to_set >= 0) { 264 *p |= mask_to_set; 265 len -= bits_to_set; 266 bits_to_set = BITS_PER_LONG; 267 mask_to_set = ~0UL; 268 p++; 269 } 270 if (len) { 271 mask_to_set &= BITMAP_LAST_WORD_MASK(size); 272 *p |= mask_to_set; 273 } 274 } 275 EXPORT_SYMBOL(__bitmap_set); 276 277 void __bitmap_clear(unsigned long *map, unsigned int start, int len) 278 { 279 unsigned long *p = map + BIT_WORD(start); 280 const unsigned int size = start + len; 281 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); 282 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); 283 284 while (len - bits_to_clear >= 0) { 285 *p &= ~mask_to_clear; 286 len -= bits_to_clear; 287 bits_to_clear = BITS_PER_LONG; 288 mask_to_clear = ~0UL; 289 p++; 290 } 291 if (len) { 292 mask_to_clear &= BITMAP_LAST_WORD_MASK(size); 293 *p &= ~mask_to_clear; 294 } 295 } 296 EXPORT_SYMBOL(__bitmap_clear); 297 298 /** 299 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area 300 * @map: The address to base the search on 301 * @size: The bitmap size in bits 302 * @start: The bitnumber to start searching at 303 * @nr: The number of zeroed bits we're looking for 304 * @align_mask: Alignment mask for zero area 305 * @align_offset: Alignment offset for zero area. 306 * 307 * The @align_mask should be one less than a power of 2; the effect is that 308 * the bit offset of all zero areas this function finds plus @align_offset 309 * is multiple of that power of 2. 310 */ 311 unsigned long bitmap_find_next_zero_area_off(unsigned long *map, 312 unsigned long size, 313 unsigned long start, 314 unsigned int nr, 315 unsigned long align_mask, 316 unsigned long align_offset) 317 { 318 unsigned long index, end, i; 319 again: 320 index = find_next_zero_bit(map, size, start); 321 322 /* Align allocation */ 323 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset; 324 325 end = index + nr; 326 if (end > size) 327 return end; 328 i = find_next_bit(map, end, index); 329 if (i < end) { 330 start = i + 1; 331 goto again; 332 } 333 return index; 334 } 335 EXPORT_SYMBOL(bitmap_find_next_zero_area_off); 336 337 /* 338 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers, 339 * second version by Paul Jackson, third by Joe Korty. 340 */ 341 342 #define CHUNKSZ 32 343 #define nbits_to_hold_value(val) fls(val) 344 #define BASEDEC 10 /* fancier cpuset lists input in decimal */ 345 346 /** 347 * __bitmap_parse - convert an ASCII hex string into a bitmap. 348 * @buf: pointer to buffer containing string. 349 * @buflen: buffer size in bytes. If string is smaller than this 350 * then it must be terminated with a \0. 351 * @is_user: location of buffer, 0 indicates kernel space 352 * @maskp: pointer to bitmap array that will contain result. 353 * @nmaskbits: size of bitmap, in bits. 354 * 355 * Commas group hex digits into chunks. Each chunk defines exactly 32 356 * bits of the resultant bitmask. No chunk may specify a value larger 357 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value 358 * then leading 0-bits are prepended. %-EINVAL is returned for illegal 359 * characters and for grouping errors such as "1,,5", ",44", "," and "". 360 * Leading and trailing whitespace accepted, but not embedded whitespace. 361 */ 362 int __bitmap_parse(const char *buf, unsigned int buflen, 363 int is_user, unsigned long *maskp, 364 int nmaskbits) 365 { 366 int c, old_c, totaldigits, ndigits, nchunks, nbits; 367 u32 chunk; 368 const char __user __force *ubuf = (const char __user __force *)buf; 369 370 bitmap_zero(maskp, nmaskbits); 371 372 nchunks = nbits = totaldigits = c = 0; 373 do { 374 chunk = 0; 375 ndigits = totaldigits; 376 377 /* Get the next chunk of the bitmap */ 378 while (buflen) { 379 old_c = c; 380 if (is_user) { 381 if (__get_user(c, ubuf++)) 382 return -EFAULT; 383 } 384 else 385 c = *buf++; 386 buflen--; 387 if (isspace(c)) 388 continue; 389 390 /* 391 * If the last character was a space and the current 392 * character isn't '\0', we've got embedded whitespace. 393 * This is a no-no, so throw an error. 394 */ 395 if (totaldigits && c && isspace(old_c)) 396 return -EINVAL; 397 398 /* A '\0' or a ',' signal the end of the chunk */ 399 if (c == '\0' || c == ',') 400 break; 401 402 if (!isxdigit(c)) 403 return -EINVAL; 404 405 /* 406 * Make sure there are at least 4 free bits in 'chunk'. 407 * If not, this hexdigit will overflow 'chunk', so 408 * throw an error. 409 */ 410 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) 411 return -EOVERFLOW; 412 413 chunk = (chunk << 4) | hex_to_bin(c); 414 totaldigits++; 415 } 416 if (ndigits == totaldigits) 417 return -EINVAL; 418 if (nchunks == 0 && chunk == 0) 419 continue; 420 421 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); 422 *maskp |= chunk; 423 nchunks++; 424 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; 425 if (nbits > nmaskbits) 426 return -EOVERFLOW; 427 } while (buflen && c == ','); 428 429 return 0; 430 } 431 EXPORT_SYMBOL(__bitmap_parse); 432 433 /** 434 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap 435 * 436 * @ubuf: pointer to user buffer containing string. 437 * @ulen: buffer size in bytes. If string is smaller than this 438 * then it must be terminated with a \0. 439 * @maskp: pointer to bitmap array that will contain result. 440 * @nmaskbits: size of bitmap, in bits. 441 * 442 * Wrapper for __bitmap_parse(), providing it with user buffer. 443 * 444 * We cannot have this as an inline function in bitmap.h because it needs 445 * linux/uaccess.h to get the access_ok() declaration and this causes 446 * cyclic dependencies. 447 */ 448 int bitmap_parse_user(const char __user *ubuf, 449 unsigned int ulen, unsigned long *maskp, 450 int nmaskbits) 451 { 452 if (!access_ok(VERIFY_READ, ubuf, ulen)) 453 return -EFAULT; 454 return __bitmap_parse((const char __force *)ubuf, 455 ulen, 1, maskp, nmaskbits); 456 457 } 458 EXPORT_SYMBOL(bitmap_parse_user); 459 460 /** 461 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string 462 * @list: indicates whether the bitmap must be list 463 * @buf: page aligned buffer into which string is placed 464 * @maskp: pointer to bitmap to convert 465 * @nmaskbits: size of bitmap, in bits 466 * 467 * Output format is a comma-separated list of decimal numbers and 468 * ranges if list is specified or hex digits grouped into comma-separated 469 * sets of 8 digits/set. Returns the number of characters written to buf. 470 * 471 * It is assumed that @buf is a pointer into a PAGE_SIZE area and that 472 * sufficient storage remains at @buf to accommodate the 473 * bitmap_print_to_pagebuf() output. 474 */ 475 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, 476 int nmaskbits) 477 { 478 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; 479 int n = 0; 480 481 if (len > 1) 482 n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : 483 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); 484 return n; 485 } 486 EXPORT_SYMBOL(bitmap_print_to_pagebuf); 487 488 /** 489 * __bitmap_parselist - convert list format ASCII string to bitmap 490 * @buf: read nul-terminated user string from this buffer 491 * @buflen: buffer size in bytes. If string is smaller than this 492 * then it must be terminated with a \0. 493 * @is_user: location of buffer, 0 indicates kernel space 494 * @maskp: write resulting mask here 495 * @nmaskbits: number of bits in mask to be written 496 * 497 * Input format is a comma-separated list of decimal numbers and 498 * ranges. Consecutively set bits are shown as two hyphen-separated 499 * decimal numbers, the smallest and largest bit numbers set in 500 * the range. 501 * Optionally each range can be postfixed to denote that only parts of it 502 * should be set. The range will divided to groups of specific size. 503 * From each group will be used only defined amount of bits. 504 * Syntax: range:used_size/group_size 505 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769 506 * 507 * Returns: 0 on success, -errno on invalid input strings. Error values: 508 * 509 * - ``-EINVAL``: second number in range smaller than first 510 * - ``-EINVAL``: invalid character in string 511 * - ``-ERANGE``: bit number specified too large for mask 512 */ 513 static int __bitmap_parselist(const char *buf, unsigned int buflen, 514 int is_user, unsigned long *maskp, 515 int nmaskbits) 516 { 517 unsigned int a, b, old_a, old_b; 518 unsigned int group_size, used_size, off; 519 int c, old_c, totaldigits, ndigits; 520 const char __user __force *ubuf = (const char __user __force *)buf; 521 int at_start, in_range, in_partial_range; 522 523 totaldigits = c = 0; 524 old_a = old_b = 0; 525 group_size = used_size = 0; 526 bitmap_zero(maskp, nmaskbits); 527 do { 528 at_start = 1; 529 in_range = 0; 530 in_partial_range = 0; 531 a = b = 0; 532 ndigits = totaldigits; 533 534 /* Get the next cpu# or a range of cpu#'s */ 535 while (buflen) { 536 old_c = c; 537 if (is_user) { 538 if (__get_user(c, ubuf++)) 539 return -EFAULT; 540 } else 541 c = *buf++; 542 buflen--; 543 if (isspace(c)) 544 continue; 545 546 /* A '\0' or a ',' signal the end of a cpu# or range */ 547 if (c == '\0' || c == ',') 548 break; 549 /* 550 * whitespaces between digits are not allowed, 551 * but it's ok if whitespaces are on head or tail. 552 * when old_c is whilespace, 553 * if totaldigits == ndigits, whitespace is on head. 554 * if whitespace is on tail, it should not run here. 555 * as c was ',' or '\0', 556 * the last code line has broken the current loop. 557 */ 558 if ((totaldigits != ndigits) && isspace(old_c)) 559 return -EINVAL; 560 561 if (c == '/') { 562 used_size = a; 563 at_start = 1; 564 in_range = 0; 565 a = b = 0; 566 continue; 567 } 568 569 if (c == ':') { 570 old_a = a; 571 old_b = b; 572 at_start = 1; 573 in_range = 0; 574 in_partial_range = 1; 575 a = b = 0; 576 continue; 577 } 578 579 if (c == '-') { 580 if (at_start || in_range) 581 return -EINVAL; 582 b = 0; 583 in_range = 1; 584 at_start = 1; 585 continue; 586 } 587 588 if (!isdigit(c)) 589 return -EINVAL; 590 591 b = b * 10 + (c - '0'); 592 if (!in_range) 593 a = b; 594 at_start = 0; 595 totaldigits++; 596 } 597 if (ndigits == totaldigits) 598 continue; 599 if (in_partial_range) { 600 group_size = a; 601 a = old_a; 602 b = old_b; 603 old_a = old_b = 0; 604 } else { 605 used_size = group_size = b - a + 1; 606 } 607 /* if no digit is after '-', it's wrong*/ 608 if (at_start && in_range) 609 return -EINVAL; 610 if (!(a <= b) || !(used_size <= group_size)) 611 return -EINVAL; 612 if (b >= nmaskbits) 613 return -ERANGE; 614 while (a <= b) { 615 off = min(b - a + 1, used_size); 616 bitmap_set(maskp, a, off); 617 a += group_size; 618 } 619 } while (buflen && c == ','); 620 return 0; 621 } 622 623 int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) 624 { 625 char *nl = strchrnul(bp, '\n'); 626 int len = nl - bp; 627 628 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits); 629 } 630 EXPORT_SYMBOL(bitmap_parselist); 631 632 633 /** 634 * bitmap_parselist_user() 635 * 636 * @ubuf: pointer to user buffer containing string. 637 * @ulen: buffer size in bytes. If string is smaller than this 638 * then it must be terminated with a \0. 639 * @maskp: pointer to bitmap array that will contain result. 640 * @nmaskbits: size of bitmap, in bits. 641 * 642 * Wrapper for bitmap_parselist(), providing it with user buffer. 643 * 644 * We cannot have this as an inline function in bitmap.h because it needs 645 * linux/uaccess.h to get the access_ok() declaration and this causes 646 * cyclic dependencies. 647 */ 648 int bitmap_parselist_user(const char __user *ubuf, 649 unsigned int ulen, unsigned long *maskp, 650 int nmaskbits) 651 { 652 if (!access_ok(VERIFY_READ, ubuf, ulen)) 653 return -EFAULT; 654 return __bitmap_parselist((const char __force *)ubuf, 655 ulen, 1, maskp, nmaskbits); 656 } 657 EXPORT_SYMBOL(bitmap_parselist_user); 658 659 660 /** 661 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap 662 * @buf: pointer to a bitmap 663 * @pos: a bit position in @buf (0 <= @pos < @nbits) 664 * @nbits: number of valid bit positions in @buf 665 * 666 * Map the bit at position @pos in @buf (of length @nbits) to the 667 * ordinal of which set bit it is. If it is not set or if @pos 668 * is not a valid bit position, map to -1. 669 * 670 * If for example, just bits 4 through 7 are set in @buf, then @pos 671 * values 4 through 7 will get mapped to 0 through 3, respectively, 672 * and other @pos values will get mapped to -1. When @pos value 7 673 * gets mapped to (returns) @ord value 3 in this example, that means 674 * that bit 7 is the 3rd (starting with 0th) set bit in @buf. 675 * 676 * The bit positions 0 through @bits are valid positions in @buf. 677 */ 678 static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) 679 { 680 if (pos >= nbits || !test_bit(pos, buf)) 681 return -1; 682 683 return __bitmap_weight(buf, pos); 684 } 685 686 /** 687 * bitmap_ord_to_pos - find position of n-th set bit in bitmap 688 * @buf: pointer to bitmap 689 * @ord: ordinal bit position (n-th set bit, n >= 0) 690 * @nbits: number of valid bit positions in @buf 691 * 692 * Map the ordinal offset of bit @ord in @buf to its position in @buf. 693 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord 694 * >= weight(buf), returns @nbits. 695 * 696 * If for example, just bits 4 through 7 are set in @buf, then @ord 697 * values 0 through 3 will get mapped to 4 through 7, respectively, 698 * and all other @ord values returns @nbits. When @ord value 3 699 * gets mapped to (returns) @pos value 7 in this example, that means 700 * that the 3rd set bit (starting with 0th) is at position 7 in @buf. 701 * 702 * The bit positions 0 through @nbits-1 are valid positions in @buf. 703 */ 704 unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) 705 { 706 unsigned int pos; 707 708 for (pos = find_first_bit(buf, nbits); 709 pos < nbits && ord; 710 pos = find_next_bit(buf, nbits, pos + 1)) 711 ord--; 712 713 return pos; 714 } 715 716 /** 717 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap 718 * @dst: remapped result 719 * @src: subset to be remapped 720 * @old: defines domain of map 721 * @new: defines range of map 722 * @nbits: number of bits in each of these bitmaps 723 * 724 * Let @old and @new define a mapping of bit positions, such that 725 * whatever position is held by the n-th set bit in @old is mapped 726 * to the n-th set bit in @new. In the more general case, allowing 727 * for the possibility that the weight 'w' of @new is less than the 728 * weight of @old, map the position of the n-th set bit in @old to 729 * the position of the m-th set bit in @new, where m == n % w. 730 * 731 * If either of the @old and @new bitmaps are empty, or if @src and 732 * @dst point to the same location, then this routine copies @src 733 * to @dst. 734 * 735 * The positions of unset bits in @old are mapped to themselves 736 * (the identify map). 737 * 738 * Apply the above specified mapping to @src, placing the result in 739 * @dst, clearing any bits previously set in @dst. 740 * 741 * For example, lets say that @old has bits 4 through 7 set, and 742 * @new has bits 12 through 15 set. This defines the mapping of bit 743 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 744 * bit positions unchanged. So if say @src comes into this routine 745 * with bits 1, 5 and 7 set, then @dst should leave with bits 1, 746 * 13 and 15 set. 747 */ 748 void bitmap_remap(unsigned long *dst, const unsigned long *src, 749 const unsigned long *old, const unsigned long *new, 750 unsigned int nbits) 751 { 752 unsigned int oldbit, w; 753 754 if (dst == src) /* following doesn't handle inplace remaps */ 755 return; 756 bitmap_zero(dst, nbits); 757 758 w = bitmap_weight(new, nbits); 759 for_each_set_bit(oldbit, src, nbits) { 760 int n = bitmap_pos_to_ord(old, oldbit, nbits); 761 762 if (n < 0 || w == 0) 763 set_bit(oldbit, dst); /* identity map */ 764 else 765 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); 766 } 767 } 768 EXPORT_SYMBOL(bitmap_remap); 769 770 /** 771 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit 772 * @oldbit: bit position to be mapped 773 * @old: defines domain of map 774 * @new: defines range of map 775 * @bits: number of bits in each of these bitmaps 776 * 777 * Let @old and @new define a mapping of bit positions, such that 778 * whatever position is held by the n-th set bit in @old is mapped 779 * to the n-th set bit in @new. In the more general case, allowing 780 * for the possibility that the weight 'w' of @new is less than the 781 * weight of @old, map the position of the n-th set bit in @old to 782 * the position of the m-th set bit in @new, where m == n % w. 783 * 784 * The positions of unset bits in @old are mapped to themselves 785 * (the identify map). 786 * 787 * Apply the above specified mapping to bit position @oldbit, returning 788 * the new bit position. 789 * 790 * For example, lets say that @old has bits 4 through 7 set, and 791 * @new has bits 12 through 15 set. This defines the mapping of bit 792 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 793 * bit positions unchanged. So if say @oldbit is 5, then this routine 794 * returns 13. 795 */ 796 int bitmap_bitremap(int oldbit, const unsigned long *old, 797 const unsigned long *new, int bits) 798 { 799 int w = bitmap_weight(new, bits); 800 int n = bitmap_pos_to_ord(old, oldbit, bits); 801 if (n < 0 || w == 0) 802 return oldbit; 803 else 804 return bitmap_ord_to_pos(new, n % w, bits); 805 } 806 EXPORT_SYMBOL(bitmap_bitremap); 807 808 /** 809 * bitmap_onto - translate one bitmap relative to another 810 * @dst: resulting translated bitmap 811 * @orig: original untranslated bitmap 812 * @relmap: bitmap relative to which translated 813 * @bits: number of bits in each of these bitmaps 814 * 815 * Set the n-th bit of @dst iff there exists some m such that the 816 * n-th bit of @relmap is set, the m-th bit of @orig is set, and 817 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. 818 * (If you understood the previous sentence the first time your 819 * read it, you're overqualified for your current job.) 820 * 821 * In other words, @orig is mapped onto (surjectively) @dst, 822 * using the map { <n, m> | the n-th bit of @relmap is the 823 * m-th set bit of @relmap }. 824 * 825 * Any set bits in @orig above bit number W, where W is the 826 * weight of (number of set bits in) @relmap are mapped nowhere. 827 * In particular, if for all bits m set in @orig, m >= W, then 828 * @dst will end up empty. In situations where the possibility 829 * of such an empty result is not desired, one way to avoid it is 830 * to use the bitmap_fold() operator, below, to first fold the 831 * @orig bitmap over itself so that all its set bits x are in the 832 * range 0 <= x < W. The bitmap_fold() operator does this by 833 * setting the bit (m % W) in @dst, for each bit (m) set in @orig. 834 * 835 * Example [1] for bitmap_onto(): 836 * Let's say @relmap has bits 30-39 set, and @orig has bits 837 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, 838 * @dst will have bits 31, 33, 35, 37 and 39 set. 839 * 840 * When bit 0 is set in @orig, it means turn on the bit in 841 * @dst corresponding to whatever is the first bit (if any) 842 * that is turned on in @relmap. Since bit 0 was off in the 843 * above example, we leave off that bit (bit 30) in @dst. 844 * 845 * When bit 1 is set in @orig (as in the above example), it 846 * means turn on the bit in @dst corresponding to whatever 847 * is the second bit that is turned on in @relmap. The second 848 * bit in @relmap that was turned on in the above example was 849 * bit 31, so we turned on bit 31 in @dst. 850 * 851 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, 852 * because they were the 4th, 6th, 8th and 10th set bits 853 * set in @relmap, and the 4th, 6th, 8th and 10th bits of 854 * @orig (i.e. bits 3, 5, 7 and 9) were also set. 855 * 856 * When bit 11 is set in @orig, it means turn on the bit in 857 * @dst corresponding to whatever is the twelfth bit that is 858 * turned on in @relmap. In the above example, there were 859 * only ten bits turned on in @relmap (30..39), so that bit 860 * 11 was set in @orig had no affect on @dst. 861 * 862 * Example [2] for bitmap_fold() + bitmap_onto(): 863 * Let's say @relmap has these ten bits set:: 864 * 865 * 40 41 42 43 45 48 53 61 74 95 866 * 867 * (for the curious, that's 40 plus the first ten terms of the 868 * Fibonacci sequence.) 869 * 870 * Further lets say we use the following code, invoking 871 * bitmap_fold() then bitmap_onto, as suggested above to 872 * avoid the possibility of an empty @dst result:: 873 * 874 * unsigned long *tmp; // a temporary bitmap's bits 875 * 876 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); 877 * bitmap_onto(dst, tmp, relmap, bits); 878 * 879 * Then this table shows what various values of @dst would be, for 880 * various @orig's. I list the zero-based positions of each set bit. 881 * The tmp column shows the intermediate result, as computed by 882 * using bitmap_fold() to fold the @orig bitmap modulo ten 883 * (the weight of @relmap): 884 * 885 * =============== ============== ================= 886 * @orig tmp @dst 887 * 0 0 40 888 * 1 1 41 889 * 9 9 95 890 * 10 0 40 [#f1]_ 891 * 1 3 5 7 1 3 5 7 41 43 48 61 892 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 893 * 0 9 18 27 0 9 8 7 40 61 74 95 894 * 0 10 20 30 0 40 895 * 0 11 22 33 0 1 2 3 40 41 42 43 896 * 0 12 24 36 0 2 4 6 40 42 45 53 897 * 78 102 211 1 2 8 41 42 74 [#f1]_ 898 * =============== ============== ================= 899 * 900 * .. [#f1] 901 * 902 * For these marked lines, if we hadn't first done bitmap_fold() 903 * into tmp, then the @dst result would have been empty. 904 * 905 * If either of @orig or @relmap is empty (no set bits), then @dst 906 * will be returned empty. 907 * 908 * If (as explained above) the only set bits in @orig are in positions 909 * m where m >= W, (where W is the weight of @relmap) then @dst will 910 * once again be returned empty. 911 * 912 * All bits in @dst not set by the above rule are cleared. 913 */ 914 void bitmap_onto(unsigned long *dst, const unsigned long *orig, 915 const unsigned long *relmap, unsigned int bits) 916 { 917 unsigned int n, m; /* same meaning as in above comment */ 918 919 if (dst == orig) /* following doesn't handle inplace mappings */ 920 return; 921 bitmap_zero(dst, bits); 922 923 /* 924 * The following code is a more efficient, but less 925 * obvious, equivalent to the loop: 926 * for (m = 0; m < bitmap_weight(relmap, bits); m++) { 927 * n = bitmap_ord_to_pos(orig, m, bits); 928 * if (test_bit(m, orig)) 929 * set_bit(n, dst); 930 * } 931 */ 932 933 m = 0; 934 for_each_set_bit(n, relmap, bits) { 935 /* m == bitmap_pos_to_ord(relmap, n, bits) */ 936 if (test_bit(m, orig)) 937 set_bit(n, dst); 938 m++; 939 } 940 } 941 EXPORT_SYMBOL(bitmap_onto); 942 943 /** 944 * bitmap_fold - fold larger bitmap into smaller, modulo specified size 945 * @dst: resulting smaller bitmap 946 * @orig: original larger bitmap 947 * @sz: specified size 948 * @nbits: number of bits in each of these bitmaps 949 * 950 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. 951 * Clear all other bits in @dst. See further the comment and 952 * Example [2] for bitmap_onto() for why and how to use this. 953 */ 954 void bitmap_fold(unsigned long *dst, const unsigned long *orig, 955 unsigned int sz, unsigned int nbits) 956 { 957 unsigned int oldbit; 958 959 if (dst == orig) /* following doesn't handle inplace mappings */ 960 return; 961 bitmap_zero(dst, nbits); 962 963 for_each_set_bit(oldbit, orig, nbits) 964 set_bit(oldbit % sz, dst); 965 } 966 EXPORT_SYMBOL(bitmap_fold); 967 968 /* 969 * Common code for bitmap_*_region() routines. 970 * bitmap: array of unsigned longs corresponding to the bitmap 971 * pos: the beginning of the region 972 * order: region size (log base 2 of number of bits) 973 * reg_op: operation(s) to perform on that region of bitmap 974 * 975 * Can set, verify and/or release a region of bits in a bitmap, 976 * depending on which combination of REG_OP_* flag bits is set. 977 * 978 * A region of a bitmap is a sequence of bits in the bitmap, of 979 * some size '1 << order' (a power of two), aligned to that same 980 * '1 << order' power of two. 981 * 982 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). 983 * Returns 0 in all other cases and reg_ops. 984 */ 985 986 enum { 987 REG_OP_ISFREE, /* true if region is all zero bits */ 988 REG_OP_ALLOC, /* set all bits in region */ 989 REG_OP_RELEASE, /* clear all bits in region */ 990 }; 991 992 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op) 993 { 994 int nbits_reg; /* number of bits in region */ 995 int index; /* index first long of region in bitmap */ 996 int offset; /* bit offset region in bitmap[index] */ 997 int nlongs_reg; /* num longs spanned by region in bitmap */ 998 int nbitsinlong; /* num bits of region in each spanned long */ 999 unsigned long mask; /* bitmask for one long of region */ 1000 int i; /* scans bitmap by longs */ 1001 int ret = 0; /* return value */ 1002 1003 /* 1004 * Either nlongs_reg == 1 (for small orders that fit in one long) 1005 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) 1006 */ 1007 nbits_reg = 1 << order; 1008 index = pos / BITS_PER_LONG; 1009 offset = pos - (index * BITS_PER_LONG); 1010 nlongs_reg = BITS_TO_LONGS(nbits_reg); 1011 nbitsinlong = min(nbits_reg, BITS_PER_LONG); 1012 1013 /* 1014 * Can't do "mask = (1UL << nbitsinlong) - 1", as that 1015 * overflows if nbitsinlong == BITS_PER_LONG. 1016 */ 1017 mask = (1UL << (nbitsinlong - 1)); 1018 mask += mask - 1; 1019 mask <<= offset; 1020 1021 switch (reg_op) { 1022 case REG_OP_ISFREE: 1023 for (i = 0; i < nlongs_reg; i++) { 1024 if (bitmap[index + i] & mask) 1025 goto done; 1026 } 1027 ret = 1; /* all bits in region free (zero) */ 1028 break; 1029 1030 case REG_OP_ALLOC: 1031 for (i = 0; i < nlongs_reg; i++) 1032 bitmap[index + i] |= mask; 1033 break; 1034 1035 case REG_OP_RELEASE: 1036 for (i = 0; i < nlongs_reg; i++) 1037 bitmap[index + i] &= ~mask; 1038 break; 1039 } 1040 done: 1041 return ret; 1042 } 1043 1044 /** 1045 * bitmap_find_free_region - find a contiguous aligned mem region 1046 * @bitmap: array of unsigned longs corresponding to the bitmap 1047 * @bits: number of bits in the bitmap 1048 * @order: region size (log base 2 of number of bits) to find 1049 * 1050 * Find a region of free (zero) bits in a @bitmap of @bits bits and 1051 * allocate them (set them to one). Only consider regions of length 1052 * a power (@order) of two, aligned to that power of two, which 1053 * makes the search algorithm much faster. 1054 * 1055 * Return the bit offset in bitmap of the allocated region, 1056 * or -errno on failure. 1057 */ 1058 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) 1059 { 1060 unsigned int pos, end; /* scans bitmap by regions of size order */ 1061 1062 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) { 1063 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1064 continue; 1065 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1066 return pos; 1067 } 1068 return -ENOMEM; 1069 } 1070 EXPORT_SYMBOL(bitmap_find_free_region); 1071 1072 /** 1073 * bitmap_release_region - release allocated bitmap region 1074 * @bitmap: array of unsigned longs corresponding to the bitmap 1075 * @pos: beginning of bit region to release 1076 * @order: region size (log base 2 of number of bits) to release 1077 * 1078 * This is the complement to __bitmap_find_free_region() and releases 1079 * the found region (by clearing it in the bitmap). 1080 * 1081 * No return value. 1082 */ 1083 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 1084 { 1085 __reg_op(bitmap, pos, order, REG_OP_RELEASE); 1086 } 1087 EXPORT_SYMBOL(bitmap_release_region); 1088 1089 /** 1090 * bitmap_allocate_region - allocate bitmap region 1091 * @bitmap: array of unsigned longs corresponding to the bitmap 1092 * @pos: beginning of bit region to allocate 1093 * @order: region size (log base 2 of number of bits) to allocate 1094 * 1095 * Allocate (set bits in) a specified region of a bitmap. 1096 * 1097 * Return 0 on success, or %-EBUSY if specified region wasn't 1098 * free (not all bits were zero). 1099 */ 1100 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 1101 { 1102 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1103 return -EBUSY; 1104 return __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1105 } 1106 EXPORT_SYMBOL(bitmap_allocate_region); 1107 1108 /** 1109 * bitmap_from_u32array - copy the contents of a u32 array of bits to bitmap 1110 * @bitmap: array of unsigned longs, the destination bitmap, non NULL 1111 * @nbits: number of bits in @bitmap 1112 * @buf: array of u32 (in host byte order), the source bitmap, non NULL 1113 * @nwords: number of u32 words in @buf 1114 * 1115 * copy min(nbits, 32*nwords) bits from @buf to @bitmap, remaining 1116 * bits between nword and nbits in @bitmap (if any) are cleared. In 1117 * last word of @bitmap, the bits beyond nbits (if any) are kept 1118 * unchanged. 1119 * 1120 * Return the number of bits effectively copied. 1121 */ 1122 unsigned int 1123 bitmap_from_u32array(unsigned long *bitmap, unsigned int nbits, 1124 const u32 *buf, unsigned int nwords) 1125 { 1126 unsigned int dst_idx, src_idx; 1127 1128 for (src_idx = dst_idx = 0; dst_idx < BITS_TO_LONGS(nbits); ++dst_idx) { 1129 unsigned long part = 0; 1130 1131 if (src_idx < nwords) 1132 part = buf[src_idx++]; 1133 1134 #if BITS_PER_LONG == 64 1135 if (src_idx < nwords) 1136 part |= ((unsigned long) buf[src_idx++]) << 32; 1137 #endif 1138 1139 if (dst_idx < nbits/BITS_PER_LONG) 1140 bitmap[dst_idx] = part; 1141 else { 1142 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); 1143 1144 bitmap[dst_idx] = (bitmap[dst_idx] & ~mask) 1145 | (part & mask); 1146 } 1147 } 1148 1149 return min_t(unsigned int, nbits, 32*nwords); 1150 } 1151 EXPORT_SYMBOL(bitmap_from_u32array); 1152 1153 /** 1154 * bitmap_to_u32array - copy the contents of bitmap to a u32 array of bits 1155 * @buf: array of u32 (in host byte order), the dest bitmap, non NULL 1156 * @nwords: number of u32 words in @buf 1157 * @bitmap: array of unsigned longs, the source bitmap, non NULL 1158 * @nbits: number of bits in @bitmap 1159 * 1160 * copy min(nbits, 32*nwords) bits from @bitmap to @buf. Remaining 1161 * bits after nbits in @buf (if any) are cleared. 1162 * 1163 * Return the number of bits effectively copied. 1164 */ 1165 unsigned int 1166 bitmap_to_u32array(u32 *buf, unsigned int nwords, 1167 const unsigned long *bitmap, unsigned int nbits) 1168 { 1169 unsigned int dst_idx = 0, src_idx = 0; 1170 1171 while (dst_idx < nwords) { 1172 unsigned long part = 0; 1173 1174 if (src_idx < BITS_TO_LONGS(nbits)) { 1175 part = bitmap[src_idx]; 1176 if (src_idx >= nbits/BITS_PER_LONG) 1177 part &= BITMAP_LAST_WORD_MASK(nbits); 1178 src_idx++; 1179 } 1180 1181 buf[dst_idx++] = part & 0xffffffffUL; 1182 1183 #if BITS_PER_LONG == 64 1184 if (dst_idx < nwords) { 1185 part >>= 32; 1186 buf[dst_idx++] = part & 0xffffffffUL; 1187 } 1188 #endif 1189 } 1190 1191 return min_t(unsigned int, nbits, 32*nwords); 1192 } 1193 EXPORT_SYMBOL(bitmap_to_u32array); 1194 1195 /** 1196 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. 1197 * @dst: destination buffer 1198 * @src: bitmap to copy 1199 * @nbits: number of bits in the bitmap 1200 * 1201 * Require nbits % BITS_PER_LONG == 0. 1202 */ 1203 #ifdef __BIG_ENDIAN 1204 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits) 1205 { 1206 unsigned int i; 1207 1208 for (i = 0; i < nbits/BITS_PER_LONG; i++) { 1209 if (BITS_PER_LONG == 64) 1210 dst[i] = cpu_to_le64(src[i]); 1211 else 1212 dst[i] = cpu_to_le32(src[i]); 1213 } 1214 } 1215 EXPORT_SYMBOL(bitmap_copy_le); 1216 #endif 1217