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_TO_LONGS(bits); 68 for (k = 0; k < lim; ++k) 69 dst[k] = ~src[k]; 70 } 71 EXPORT_SYMBOL(__bitmap_complement); 72 73 /** 74 * __bitmap_shift_right - logical right shift of the bits in a bitmap 75 * @dst : destination bitmap 76 * @src : source bitmap 77 * @shift : shift by this many bits 78 * @nbits : bitmap size, in bits 79 * 80 * Shifting right (dividing) means moving bits in the MS -> LS bit 81 * direction. Zeros are fed into the vacated MS positions and the 82 * LS bits shifted off the bottom are lost. 83 */ 84 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, 85 unsigned shift, unsigned nbits) 86 { 87 unsigned k, lim = BITS_TO_LONGS(nbits); 88 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; 89 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits); 90 for (k = 0; off + k < lim; ++k) { 91 unsigned long upper, lower; 92 93 /* 94 * If shift is not word aligned, take lower rem bits of 95 * word above and make them the top rem bits of result. 96 */ 97 if (!rem || off + k + 1 >= lim) 98 upper = 0; 99 else { 100 upper = src[off + k + 1]; 101 if (off + k + 1 == lim - 1) 102 upper &= mask; 103 upper <<= (BITS_PER_LONG - rem); 104 } 105 lower = src[off + k]; 106 if (off + k == lim - 1) 107 lower &= mask; 108 lower >>= rem; 109 dst[k] = lower | upper; 110 } 111 if (off) 112 memset(&dst[lim - off], 0, off*sizeof(unsigned long)); 113 } 114 EXPORT_SYMBOL(__bitmap_shift_right); 115 116 117 /** 118 * __bitmap_shift_left - logical left shift of the bits in a bitmap 119 * @dst : destination bitmap 120 * @src : source bitmap 121 * @shift : shift by this many bits 122 * @nbits : bitmap size, in bits 123 * 124 * Shifting left (multiplying) means moving bits in the LS -> MS 125 * direction. Zeros are fed into the vacated LS bit positions 126 * and those MS bits shifted off the top are lost. 127 */ 128 129 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, 130 unsigned int shift, unsigned int nbits) 131 { 132 int k; 133 unsigned int lim = BITS_TO_LONGS(nbits); 134 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; 135 for (k = lim - off - 1; k >= 0; --k) { 136 unsigned long upper, lower; 137 138 /* 139 * If shift is not word aligned, take upper rem bits of 140 * word below and make them the bottom rem bits of result. 141 */ 142 if (rem && k > 0) 143 lower = src[k - 1] >> (BITS_PER_LONG - rem); 144 else 145 lower = 0; 146 upper = src[k] << rem; 147 dst[k + off] = lower | upper; 148 } 149 if (off) 150 memset(dst, 0, off*sizeof(unsigned long)); 151 } 152 EXPORT_SYMBOL(__bitmap_shift_left); 153 154 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, 155 const unsigned long *bitmap2, unsigned int bits) 156 { 157 unsigned int k; 158 unsigned int lim = bits/BITS_PER_LONG; 159 unsigned long result = 0; 160 161 for (k = 0; k < lim; k++) 162 result |= (dst[k] = bitmap1[k] & bitmap2[k]); 163 if (bits % BITS_PER_LONG) 164 result |= (dst[k] = bitmap1[k] & bitmap2[k] & 165 BITMAP_LAST_WORD_MASK(bits)); 166 return result != 0; 167 } 168 EXPORT_SYMBOL(__bitmap_and); 169 170 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, 171 const unsigned long *bitmap2, unsigned int bits) 172 { 173 unsigned int k; 174 unsigned int nr = BITS_TO_LONGS(bits); 175 176 for (k = 0; k < nr; k++) 177 dst[k] = bitmap1[k] | bitmap2[k]; 178 } 179 EXPORT_SYMBOL(__bitmap_or); 180 181 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, 182 const unsigned long *bitmap2, unsigned int bits) 183 { 184 unsigned int k; 185 unsigned int nr = BITS_TO_LONGS(bits); 186 187 for (k = 0; k < nr; k++) 188 dst[k] = bitmap1[k] ^ bitmap2[k]; 189 } 190 EXPORT_SYMBOL(__bitmap_xor); 191 192 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, 193 const unsigned long *bitmap2, unsigned int bits) 194 { 195 unsigned int k; 196 unsigned int lim = bits/BITS_PER_LONG; 197 unsigned long result = 0; 198 199 for (k = 0; k < lim; k++) 200 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); 201 if (bits % BITS_PER_LONG) 202 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & 203 BITMAP_LAST_WORD_MASK(bits)); 204 return result != 0; 205 } 206 EXPORT_SYMBOL(__bitmap_andnot); 207 208 int __bitmap_intersects(const unsigned long *bitmap1, 209 const unsigned long *bitmap2, unsigned int bits) 210 { 211 unsigned int k, lim = bits/BITS_PER_LONG; 212 for (k = 0; k < lim; ++k) 213 if (bitmap1[k] & bitmap2[k]) 214 return 1; 215 216 if (bits % BITS_PER_LONG) 217 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 218 return 1; 219 return 0; 220 } 221 EXPORT_SYMBOL(__bitmap_intersects); 222 223 int __bitmap_subset(const unsigned long *bitmap1, 224 const unsigned long *bitmap2, unsigned int bits) 225 { 226 unsigned int k, lim = bits/BITS_PER_LONG; 227 for (k = 0; k < lim; ++k) 228 if (bitmap1[k] & ~bitmap2[k]) 229 return 0; 230 231 if (bits % BITS_PER_LONG) 232 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 233 return 0; 234 return 1; 235 } 236 EXPORT_SYMBOL(__bitmap_subset); 237 238 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) 239 { 240 unsigned int k, lim = bits/BITS_PER_LONG; 241 int w = 0; 242 243 for (k = 0; k < lim; k++) 244 w += hweight_long(bitmap[k]); 245 246 if (bits % BITS_PER_LONG) 247 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); 248 249 return w; 250 } 251 EXPORT_SYMBOL(__bitmap_weight); 252 253 void __bitmap_set(unsigned long *map, unsigned int start, int len) 254 { 255 unsigned long *p = map + BIT_WORD(start); 256 const unsigned int size = start + len; 257 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); 258 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); 259 260 while (len - bits_to_set >= 0) { 261 *p |= mask_to_set; 262 len -= bits_to_set; 263 bits_to_set = BITS_PER_LONG; 264 mask_to_set = ~0UL; 265 p++; 266 } 267 if (len) { 268 mask_to_set &= BITMAP_LAST_WORD_MASK(size); 269 *p |= mask_to_set; 270 } 271 } 272 EXPORT_SYMBOL(__bitmap_set); 273 274 void __bitmap_clear(unsigned long *map, unsigned int start, int len) 275 { 276 unsigned long *p = map + BIT_WORD(start); 277 const unsigned int size = start + len; 278 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); 279 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); 280 281 while (len - bits_to_clear >= 0) { 282 *p &= ~mask_to_clear; 283 len -= bits_to_clear; 284 bits_to_clear = BITS_PER_LONG; 285 mask_to_clear = ~0UL; 286 p++; 287 } 288 if (len) { 289 mask_to_clear &= BITMAP_LAST_WORD_MASK(size); 290 *p &= ~mask_to_clear; 291 } 292 } 293 EXPORT_SYMBOL(__bitmap_clear); 294 295 /** 296 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area 297 * @map: The address to base the search on 298 * @size: The bitmap size in bits 299 * @start: The bitnumber to start searching at 300 * @nr: The number of zeroed bits we're looking for 301 * @align_mask: Alignment mask for zero area 302 * @align_offset: Alignment offset for zero area. 303 * 304 * The @align_mask should be one less than a power of 2; the effect is that 305 * the bit offset of all zero areas this function finds plus @align_offset 306 * is multiple of that power of 2. 307 */ 308 unsigned long bitmap_find_next_zero_area_off(unsigned long *map, 309 unsigned long size, 310 unsigned long start, 311 unsigned int nr, 312 unsigned long align_mask, 313 unsigned long align_offset) 314 { 315 unsigned long index, end, i; 316 again: 317 index = find_next_zero_bit(map, size, start); 318 319 /* Align allocation */ 320 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset; 321 322 end = index + nr; 323 if (end > size) 324 return end; 325 i = find_next_bit(map, end, index); 326 if (i < end) { 327 start = i + 1; 328 goto again; 329 } 330 return index; 331 } 332 EXPORT_SYMBOL(bitmap_find_next_zero_area_off); 333 334 /* 335 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers, 336 * second version by Paul Jackson, third by Joe Korty. 337 */ 338 339 #define CHUNKSZ 32 340 #define nbits_to_hold_value(val) fls(val) 341 #define BASEDEC 10 /* fancier cpuset lists input in decimal */ 342 343 /** 344 * __bitmap_parse - convert an ASCII hex string into a bitmap. 345 * @buf: pointer to buffer containing string. 346 * @buflen: buffer size in bytes. If string is smaller than this 347 * then it must be terminated with a \0. 348 * @is_user: location of buffer, 0 indicates kernel space 349 * @maskp: pointer to bitmap array that will contain result. 350 * @nmaskbits: size of bitmap, in bits. 351 * 352 * Commas group hex digits into chunks. Each chunk defines exactly 32 353 * bits of the resultant bitmask. No chunk may specify a value larger 354 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value 355 * then leading 0-bits are prepended. %-EINVAL is returned for illegal 356 * characters and for grouping errors such as "1,,5", ",44", "," and "". 357 * Leading and trailing whitespace accepted, but not embedded whitespace. 358 */ 359 int __bitmap_parse(const char *buf, unsigned int buflen, 360 int is_user, unsigned long *maskp, 361 int nmaskbits) 362 { 363 int c, old_c, totaldigits, ndigits, nchunks, nbits; 364 u32 chunk; 365 const char __user __force *ubuf = (const char __user __force *)buf; 366 367 bitmap_zero(maskp, nmaskbits); 368 369 nchunks = nbits = totaldigits = c = 0; 370 do { 371 chunk = 0; 372 ndigits = totaldigits; 373 374 /* Get the next chunk of the bitmap */ 375 while (buflen) { 376 old_c = c; 377 if (is_user) { 378 if (__get_user(c, ubuf++)) 379 return -EFAULT; 380 } 381 else 382 c = *buf++; 383 buflen--; 384 if (isspace(c)) 385 continue; 386 387 /* 388 * If the last character was a space and the current 389 * character isn't '\0', we've got embedded whitespace. 390 * This is a no-no, so throw an error. 391 */ 392 if (totaldigits && c && isspace(old_c)) 393 return -EINVAL; 394 395 /* A '\0' or a ',' signal the end of the chunk */ 396 if (c == '\0' || c == ',') 397 break; 398 399 if (!isxdigit(c)) 400 return -EINVAL; 401 402 /* 403 * Make sure there are at least 4 free bits in 'chunk'. 404 * If not, this hexdigit will overflow 'chunk', so 405 * throw an error. 406 */ 407 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) 408 return -EOVERFLOW; 409 410 chunk = (chunk << 4) | hex_to_bin(c); 411 totaldigits++; 412 } 413 if (ndigits == totaldigits) 414 return -EINVAL; 415 if (nchunks == 0 && chunk == 0) 416 continue; 417 418 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); 419 *maskp |= chunk; 420 nchunks++; 421 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; 422 if (nbits > nmaskbits) 423 return -EOVERFLOW; 424 } while (buflen && c == ','); 425 426 return 0; 427 } 428 EXPORT_SYMBOL(__bitmap_parse); 429 430 /** 431 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap 432 * 433 * @ubuf: pointer to user buffer containing string. 434 * @ulen: buffer size in bytes. If string is smaller than this 435 * then it must be terminated with a \0. 436 * @maskp: pointer to bitmap array that will contain result. 437 * @nmaskbits: size of bitmap, in bits. 438 * 439 * Wrapper for __bitmap_parse(), providing it with user buffer. 440 * 441 * We cannot have this as an inline function in bitmap.h because it needs 442 * linux/uaccess.h to get the access_ok() declaration and this causes 443 * cyclic dependencies. 444 */ 445 int bitmap_parse_user(const char __user *ubuf, 446 unsigned int ulen, unsigned long *maskp, 447 int nmaskbits) 448 { 449 if (!access_ok(VERIFY_READ, ubuf, ulen)) 450 return -EFAULT; 451 return __bitmap_parse((const char __force *)ubuf, 452 ulen, 1, maskp, nmaskbits); 453 454 } 455 EXPORT_SYMBOL(bitmap_parse_user); 456 457 /** 458 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string 459 * @list: indicates whether the bitmap must be list 460 * @buf: page aligned buffer into which string is placed 461 * @maskp: pointer to bitmap to convert 462 * @nmaskbits: size of bitmap, in bits 463 * 464 * Output format is a comma-separated list of decimal numbers and 465 * ranges if list is specified or hex digits grouped into comma-separated 466 * sets of 8 digits/set. Returns the number of characters written to buf. 467 * 468 * It is assumed that @buf is a pointer into a PAGE_SIZE area and that 469 * sufficient storage remains at @buf to accommodate the 470 * bitmap_print_to_pagebuf() output. 471 */ 472 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, 473 int nmaskbits) 474 { 475 ptrdiff_t len = PTR_ALIGN(buf + PAGE_SIZE - 1, PAGE_SIZE) - buf; 476 int n = 0; 477 478 if (len > 1) 479 n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : 480 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); 481 return n; 482 } 483 EXPORT_SYMBOL(bitmap_print_to_pagebuf); 484 485 /** 486 * __bitmap_parselist - convert list format ASCII string to bitmap 487 * @buf: read nul-terminated user string from this buffer 488 * @buflen: buffer size in bytes. If string is smaller than this 489 * then it must be terminated with a \0. 490 * @is_user: location of buffer, 0 indicates kernel space 491 * @maskp: write resulting mask here 492 * @nmaskbits: number of bits in mask to be written 493 * 494 * Input format is a comma-separated list of decimal numbers and 495 * ranges. Consecutively set bits are shown as two hyphen-separated 496 * decimal numbers, the smallest and largest bit numbers set in 497 * the range. 498 * Optionally each range can be postfixed to denote that only parts of it 499 * should be set. The range will divided to groups of specific size. 500 * From each group will be used only defined amount of bits. 501 * Syntax: range:used_size/group_size 502 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769 503 * 504 * Returns: 0 on success, -errno on invalid input strings. Error values: 505 * 506 * - ``-EINVAL``: second number in range smaller than first 507 * - ``-EINVAL``: invalid character in string 508 * - ``-ERANGE``: bit number specified too large for mask 509 */ 510 static int __bitmap_parselist(const char *buf, unsigned int buflen, 511 int is_user, unsigned long *maskp, 512 int nmaskbits) 513 { 514 unsigned int a, b, old_a, old_b; 515 unsigned int group_size, used_size, off; 516 int c, old_c, totaldigits, ndigits; 517 const char __user __force *ubuf = (const char __user __force *)buf; 518 int at_start, in_range, in_partial_range; 519 520 totaldigits = c = 0; 521 old_a = old_b = 0; 522 group_size = used_size = 0; 523 bitmap_zero(maskp, nmaskbits); 524 do { 525 at_start = 1; 526 in_range = 0; 527 in_partial_range = 0; 528 a = b = 0; 529 ndigits = totaldigits; 530 531 /* Get the next cpu# or a range of cpu#'s */ 532 while (buflen) { 533 old_c = c; 534 if (is_user) { 535 if (__get_user(c, ubuf++)) 536 return -EFAULT; 537 } else 538 c = *buf++; 539 buflen--; 540 if (isspace(c)) 541 continue; 542 543 /* A '\0' or a ',' signal the end of a cpu# or range */ 544 if (c == '\0' || c == ',') 545 break; 546 /* 547 * whitespaces between digits are not allowed, 548 * but it's ok if whitespaces are on head or tail. 549 * when old_c is whilespace, 550 * if totaldigits == ndigits, whitespace is on head. 551 * if whitespace is on tail, it should not run here. 552 * as c was ',' or '\0', 553 * the last code line has broken the current loop. 554 */ 555 if ((totaldigits != ndigits) && isspace(old_c)) 556 return -EINVAL; 557 558 if (c == '/') { 559 used_size = a; 560 at_start = 1; 561 in_range = 0; 562 a = b = 0; 563 continue; 564 } 565 566 if (c == ':') { 567 old_a = a; 568 old_b = b; 569 at_start = 1; 570 in_range = 0; 571 in_partial_range = 1; 572 a = b = 0; 573 continue; 574 } 575 576 if (c == '-') { 577 if (at_start || in_range) 578 return -EINVAL; 579 b = 0; 580 in_range = 1; 581 at_start = 1; 582 continue; 583 } 584 585 if (!isdigit(c)) 586 return -EINVAL; 587 588 b = b * 10 + (c - '0'); 589 if (!in_range) 590 a = b; 591 at_start = 0; 592 totaldigits++; 593 } 594 if (ndigits == totaldigits) 595 continue; 596 if (in_partial_range) { 597 group_size = a; 598 a = old_a; 599 b = old_b; 600 old_a = old_b = 0; 601 } else { 602 used_size = group_size = b - a + 1; 603 } 604 /* if no digit is after '-', it's wrong*/ 605 if (at_start && in_range) 606 return -EINVAL; 607 if (!(a <= b) || group_size == 0 || !(used_size <= group_size)) 608 return -EINVAL; 609 if (b >= nmaskbits) 610 return -ERANGE; 611 while (a <= b) { 612 off = min(b - a + 1, used_size); 613 bitmap_set(maskp, a, off); 614 a += group_size; 615 } 616 } while (buflen && c == ','); 617 return 0; 618 } 619 620 int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) 621 { 622 char *nl = strchrnul(bp, '\n'); 623 int len = nl - bp; 624 625 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits); 626 } 627 EXPORT_SYMBOL(bitmap_parselist); 628 629 630 /** 631 * bitmap_parselist_user() 632 * 633 * @ubuf: pointer to user buffer containing string. 634 * @ulen: buffer size in bytes. If string is smaller than this 635 * then it must be terminated with a \0. 636 * @maskp: pointer to bitmap array that will contain result. 637 * @nmaskbits: size of bitmap, in bits. 638 * 639 * Wrapper for bitmap_parselist(), providing it with user buffer. 640 * 641 * We cannot have this as an inline function in bitmap.h because it needs 642 * linux/uaccess.h to get the access_ok() declaration and this causes 643 * cyclic dependencies. 644 */ 645 int bitmap_parselist_user(const char __user *ubuf, 646 unsigned int ulen, unsigned long *maskp, 647 int nmaskbits) 648 { 649 if (!access_ok(VERIFY_READ, ubuf, ulen)) 650 return -EFAULT; 651 return __bitmap_parselist((const char __force *)ubuf, 652 ulen, 1, maskp, nmaskbits); 653 } 654 EXPORT_SYMBOL(bitmap_parselist_user); 655 656 657 /** 658 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap 659 * @buf: pointer to a bitmap 660 * @pos: a bit position in @buf (0 <= @pos < @nbits) 661 * @nbits: number of valid bit positions in @buf 662 * 663 * Map the bit at position @pos in @buf (of length @nbits) to the 664 * ordinal of which set bit it is. If it is not set or if @pos 665 * is not a valid bit position, map to -1. 666 * 667 * If for example, just bits 4 through 7 are set in @buf, then @pos 668 * values 4 through 7 will get mapped to 0 through 3, respectively, 669 * and other @pos values will get mapped to -1. When @pos value 7 670 * gets mapped to (returns) @ord value 3 in this example, that means 671 * that bit 7 is the 3rd (starting with 0th) set bit in @buf. 672 * 673 * The bit positions 0 through @bits are valid positions in @buf. 674 */ 675 static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits) 676 { 677 if (pos >= nbits || !test_bit(pos, buf)) 678 return -1; 679 680 return __bitmap_weight(buf, pos); 681 } 682 683 /** 684 * bitmap_ord_to_pos - find position of n-th set bit in bitmap 685 * @buf: pointer to bitmap 686 * @ord: ordinal bit position (n-th set bit, n >= 0) 687 * @nbits: number of valid bit positions in @buf 688 * 689 * Map the ordinal offset of bit @ord in @buf to its position in @buf. 690 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord 691 * >= weight(buf), returns @nbits. 692 * 693 * If for example, just bits 4 through 7 are set in @buf, then @ord 694 * values 0 through 3 will get mapped to 4 through 7, respectively, 695 * and all other @ord values returns @nbits. When @ord value 3 696 * gets mapped to (returns) @pos value 7 in this example, that means 697 * that the 3rd set bit (starting with 0th) is at position 7 in @buf. 698 * 699 * The bit positions 0 through @nbits-1 are valid positions in @buf. 700 */ 701 unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits) 702 { 703 unsigned int pos; 704 705 for (pos = find_first_bit(buf, nbits); 706 pos < nbits && ord; 707 pos = find_next_bit(buf, nbits, pos + 1)) 708 ord--; 709 710 return pos; 711 } 712 713 /** 714 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap 715 * @dst: remapped result 716 * @src: subset to be remapped 717 * @old: defines domain of map 718 * @new: defines range of map 719 * @nbits: number of bits in each of these bitmaps 720 * 721 * Let @old and @new define a mapping of bit positions, such that 722 * whatever position is held by the n-th set bit in @old is mapped 723 * to the n-th set bit in @new. In the more general case, allowing 724 * for the possibility that the weight 'w' of @new is less than the 725 * weight of @old, map the position of the n-th set bit in @old to 726 * the position of the m-th set bit in @new, where m == n % w. 727 * 728 * If either of the @old and @new bitmaps are empty, or if @src and 729 * @dst point to the same location, then this routine copies @src 730 * to @dst. 731 * 732 * The positions of unset bits in @old are mapped to themselves 733 * (the identify map). 734 * 735 * Apply the above specified mapping to @src, placing the result in 736 * @dst, clearing any bits previously set in @dst. 737 * 738 * For example, lets say that @old has bits 4 through 7 set, and 739 * @new has bits 12 through 15 set. This defines the mapping of bit 740 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 741 * bit positions unchanged. So if say @src comes into this routine 742 * with bits 1, 5 and 7 set, then @dst should leave with bits 1, 743 * 13 and 15 set. 744 */ 745 void bitmap_remap(unsigned long *dst, const unsigned long *src, 746 const unsigned long *old, const unsigned long *new, 747 unsigned int nbits) 748 { 749 unsigned int oldbit, w; 750 751 if (dst == src) /* following doesn't handle inplace remaps */ 752 return; 753 bitmap_zero(dst, nbits); 754 755 w = bitmap_weight(new, nbits); 756 for_each_set_bit(oldbit, src, nbits) { 757 int n = bitmap_pos_to_ord(old, oldbit, nbits); 758 759 if (n < 0 || w == 0) 760 set_bit(oldbit, dst); /* identity map */ 761 else 762 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst); 763 } 764 } 765 EXPORT_SYMBOL(bitmap_remap); 766 767 /** 768 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit 769 * @oldbit: bit position to be mapped 770 * @old: defines domain of map 771 * @new: defines range of map 772 * @bits: number of bits in each of these bitmaps 773 * 774 * Let @old and @new define a mapping of bit positions, such that 775 * whatever position is held by the n-th set bit in @old is mapped 776 * to the n-th set bit in @new. In the more general case, allowing 777 * for the possibility that the weight 'w' of @new is less than the 778 * weight of @old, map the position of the n-th set bit in @old to 779 * the position of the m-th set bit in @new, where m == n % w. 780 * 781 * The positions of unset bits in @old are mapped to themselves 782 * (the identify map). 783 * 784 * Apply the above specified mapping to bit position @oldbit, returning 785 * the new bit position. 786 * 787 * For example, lets say that @old has bits 4 through 7 set, and 788 * @new has bits 12 through 15 set. This defines the mapping of bit 789 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 790 * bit positions unchanged. So if say @oldbit is 5, then this routine 791 * returns 13. 792 */ 793 int bitmap_bitremap(int oldbit, const unsigned long *old, 794 const unsigned long *new, int bits) 795 { 796 int w = bitmap_weight(new, bits); 797 int n = bitmap_pos_to_ord(old, oldbit, bits); 798 if (n < 0 || w == 0) 799 return oldbit; 800 else 801 return bitmap_ord_to_pos(new, n % w, bits); 802 } 803 EXPORT_SYMBOL(bitmap_bitremap); 804 805 /** 806 * bitmap_onto - translate one bitmap relative to another 807 * @dst: resulting translated bitmap 808 * @orig: original untranslated bitmap 809 * @relmap: bitmap relative to which translated 810 * @bits: number of bits in each of these bitmaps 811 * 812 * Set the n-th bit of @dst iff there exists some m such that the 813 * n-th bit of @relmap is set, the m-th bit of @orig is set, and 814 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. 815 * (If you understood the previous sentence the first time your 816 * read it, you're overqualified for your current job.) 817 * 818 * In other words, @orig is mapped onto (surjectively) @dst, 819 * using the map { <n, m> | the n-th bit of @relmap is the 820 * m-th set bit of @relmap }. 821 * 822 * Any set bits in @orig above bit number W, where W is the 823 * weight of (number of set bits in) @relmap are mapped nowhere. 824 * In particular, if for all bits m set in @orig, m >= W, then 825 * @dst will end up empty. In situations where the possibility 826 * of such an empty result is not desired, one way to avoid it is 827 * to use the bitmap_fold() operator, below, to first fold the 828 * @orig bitmap over itself so that all its set bits x are in the 829 * range 0 <= x < W. The bitmap_fold() operator does this by 830 * setting the bit (m % W) in @dst, for each bit (m) set in @orig. 831 * 832 * Example [1] for bitmap_onto(): 833 * Let's say @relmap has bits 30-39 set, and @orig has bits 834 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, 835 * @dst will have bits 31, 33, 35, 37 and 39 set. 836 * 837 * When bit 0 is set in @orig, it means turn on the bit in 838 * @dst corresponding to whatever is the first bit (if any) 839 * that is turned on in @relmap. Since bit 0 was off in the 840 * above example, we leave off that bit (bit 30) in @dst. 841 * 842 * When bit 1 is set in @orig (as in the above example), it 843 * means turn on the bit in @dst corresponding to whatever 844 * is the second bit that is turned on in @relmap. The second 845 * bit in @relmap that was turned on in the above example was 846 * bit 31, so we turned on bit 31 in @dst. 847 * 848 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, 849 * because they were the 4th, 6th, 8th and 10th set bits 850 * set in @relmap, and the 4th, 6th, 8th and 10th bits of 851 * @orig (i.e. bits 3, 5, 7 and 9) were also set. 852 * 853 * When bit 11 is set in @orig, it means turn on the bit in 854 * @dst corresponding to whatever is the twelfth bit that is 855 * turned on in @relmap. In the above example, there were 856 * only ten bits turned on in @relmap (30..39), so that bit 857 * 11 was set in @orig had no affect on @dst. 858 * 859 * Example [2] for bitmap_fold() + bitmap_onto(): 860 * Let's say @relmap has these ten bits set:: 861 * 862 * 40 41 42 43 45 48 53 61 74 95 863 * 864 * (for the curious, that's 40 plus the first ten terms of the 865 * Fibonacci sequence.) 866 * 867 * Further lets say we use the following code, invoking 868 * bitmap_fold() then bitmap_onto, as suggested above to 869 * avoid the possibility of an empty @dst result:: 870 * 871 * unsigned long *tmp; // a temporary bitmap's bits 872 * 873 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); 874 * bitmap_onto(dst, tmp, relmap, bits); 875 * 876 * Then this table shows what various values of @dst would be, for 877 * various @orig's. I list the zero-based positions of each set bit. 878 * The tmp column shows the intermediate result, as computed by 879 * using bitmap_fold() to fold the @orig bitmap modulo ten 880 * (the weight of @relmap): 881 * 882 * =============== ============== ================= 883 * @orig tmp @dst 884 * 0 0 40 885 * 1 1 41 886 * 9 9 95 887 * 10 0 40 [#f1]_ 888 * 1 3 5 7 1 3 5 7 41 43 48 61 889 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 890 * 0 9 18 27 0 9 8 7 40 61 74 95 891 * 0 10 20 30 0 40 892 * 0 11 22 33 0 1 2 3 40 41 42 43 893 * 0 12 24 36 0 2 4 6 40 42 45 53 894 * 78 102 211 1 2 8 41 42 74 [#f1]_ 895 * =============== ============== ================= 896 * 897 * .. [#f1] 898 * 899 * For these marked lines, if we hadn't first done bitmap_fold() 900 * into tmp, then the @dst result would have been empty. 901 * 902 * If either of @orig or @relmap is empty (no set bits), then @dst 903 * will be returned empty. 904 * 905 * If (as explained above) the only set bits in @orig are in positions 906 * m where m >= W, (where W is the weight of @relmap) then @dst will 907 * once again be returned empty. 908 * 909 * All bits in @dst not set by the above rule are cleared. 910 */ 911 void bitmap_onto(unsigned long *dst, const unsigned long *orig, 912 const unsigned long *relmap, unsigned int bits) 913 { 914 unsigned int n, m; /* same meaning as in above comment */ 915 916 if (dst == orig) /* following doesn't handle inplace mappings */ 917 return; 918 bitmap_zero(dst, bits); 919 920 /* 921 * The following code is a more efficient, but less 922 * obvious, equivalent to the loop: 923 * for (m = 0; m < bitmap_weight(relmap, bits); m++) { 924 * n = bitmap_ord_to_pos(orig, m, bits); 925 * if (test_bit(m, orig)) 926 * set_bit(n, dst); 927 * } 928 */ 929 930 m = 0; 931 for_each_set_bit(n, relmap, bits) { 932 /* m == bitmap_pos_to_ord(relmap, n, bits) */ 933 if (test_bit(m, orig)) 934 set_bit(n, dst); 935 m++; 936 } 937 } 938 EXPORT_SYMBOL(bitmap_onto); 939 940 /** 941 * bitmap_fold - fold larger bitmap into smaller, modulo specified size 942 * @dst: resulting smaller bitmap 943 * @orig: original larger bitmap 944 * @sz: specified size 945 * @nbits: number of bits in each of these bitmaps 946 * 947 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. 948 * Clear all other bits in @dst. See further the comment and 949 * Example [2] for bitmap_onto() for why and how to use this. 950 */ 951 void bitmap_fold(unsigned long *dst, const unsigned long *orig, 952 unsigned int sz, unsigned int nbits) 953 { 954 unsigned int oldbit; 955 956 if (dst == orig) /* following doesn't handle inplace mappings */ 957 return; 958 bitmap_zero(dst, nbits); 959 960 for_each_set_bit(oldbit, orig, nbits) 961 set_bit(oldbit % sz, dst); 962 } 963 EXPORT_SYMBOL(bitmap_fold); 964 965 /* 966 * Common code for bitmap_*_region() routines. 967 * bitmap: array of unsigned longs corresponding to the bitmap 968 * pos: the beginning of the region 969 * order: region size (log base 2 of number of bits) 970 * reg_op: operation(s) to perform on that region of bitmap 971 * 972 * Can set, verify and/or release a region of bits in a bitmap, 973 * depending on which combination of REG_OP_* flag bits is set. 974 * 975 * A region of a bitmap is a sequence of bits in the bitmap, of 976 * some size '1 << order' (a power of two), aligned to that same 977 * '1 << order' power of two. 978 * 979 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). 980 * Returns 0 in all other cases and reg_ops. 981 */ 982 983 enum { 984 REG_OP_ISFREE, /* true if region is all zero bits */ 985 REG_OP_ALLOC, /* set all bits in region */ 986 REG_OP_RELEASE, /* clear all bits in region */ 987 }; 988 989 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op) 990 { 991 int nbits_reg; /* number of bits in region */ 992 int index; /* index first long of region in bitmap */ 993 int offset; /* bit offset region in bitmap[index] */ 994 int nlongs_reg; /* num longs spanned by region in bitmap */ 995 int nbitsinlong; /* num bits of region in each spanned long */ 996 unsigned long mask; /* bitmask for one long of region */ 997 int i; /* scans bitmap by longs */ 998 int ret = 0; /* return value */ 999 1000 /* 1001 * Either nlongs_reg == 1 (for small orders that fit in one long) 1002 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) 1003 */ 1004 nbits_reg = 1 << order; 1005 index = pos / BITS_PER_LONG; 1006 offset = pos - (index * BITS_PER_LONG); 1007 nlongs_reg = BITS_TO_LONGS(nbits_reg); 1008 nbitsinlong = min(nbits_reg, BITS_PER_LONG); 1009 1010 /* 1011 * Can't do "mask = (1UL << nbitsinlong) - 1", as that 1012 * overflows if nbitsinlong == BITS_PER_LONG. 1013 */ 1014 mask = (1UL << (nbitsinlong - 1)); 1015 mask += mask - 1; 1016 mask <<= offset; 1017 1018 switch (reg_op) { 1019 case REG_OP_ISFREE: 1020 for (i = 0; i < nlongs_reg; i++) { 1021 if (bitmap[index + i] & mask) 1022 goto done; 1023 } 1024 ret = 1; /* all bits in region free (zero) */ 1025 break; 1026 1027 case REG_OP_ALLOC: 1028 for (i = 0; i < nlongs_reg; i++) 1029 bitmap[index + i] |= mask; 1030 break; 1031 1032 case REG_OP_RELEASE: 1033 for (i = 0; i < nlongs_reg; i++) 1034 bitmap[index + i] &= ~mask; 1035 break; 1036 } 1037 done: 1038 return ret; 1039 } 1040 1041 /** 1042 * bitmap_find_free_region - find a contiguous aligned mem region 1043 * @bitmap: array of unsigned longs corresponding to the bitmap 1044 * @bits: number of bits in the bitmap 1045 * @order: region size (log base 2 of number of bits) to find 1046 * 1047 * Find a region of free (zero) bits in a @bitmap of @bits bits and 1048 * allocate them (set them to one). Only consider regions of length 1049 * a power (@order) of two, aligned to that power of two, which 1050 * makes the search algorithm much faster. 1051 * 1052 * Return the bit offset in bitmap of the allocated region, 1053 * or -errno on failure. 1054 */ 1055 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) 1056 { 1057 unsigned int pos, end; /* scans bitmap by regions of size order */ 1058 1059 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) { 1060 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1061 continue; 1062 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1063 return pos; 1064 } 1065 return -ENOMEM; 1066 } 1067 EXPORT_SYMBOL(bitmap_find_free_region); 1068 1069 /** 1070 * bitmap_release_region - release allocated bitmap region 1071 * @bitmap: array of unsigned longs corresponding to the bitmap 1072 * @pos: beginning of bit region to release 1073 * @order: region size (log base 2 of number of bits) to release 1074 * 1075 * This is the complement to __bitmap_find_free_region() and releases 1076 * the found region (by clearing it in the bitmap). 1077 * 1078 * No return value. 1079 */ 1080 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 1081 { 1082 __reg_op(bitmap, pos, order, REG_OP_RELEASE); 1083 } 1084 EXPORT_SYMBOL(bitmap_release_region); 1085 1086 /** 1087 * bitmap_allocate_region - allocate bitmap region 1088 * @bitmap: array of unsigned longs corresponding to the bitmap 1089 * @pos: beginning of bit region to allocate 1090 * @order: region size (log base 2 of number of bits) to allocate 1091 * 1092 * Allocate (set bits in) a specified region of a bitmap. 1093 * 1094 * Return 0 on success, or %-EBUSY if specified region wasn't 1095 * free (not all bits were zero). 1096 */ 1097 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 1098 { 1099 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1100 return -EBUSY; 1101 return __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1102 } 1103 EXPORT_SYMBOL(bitmap_allocate_region); 1104 1105 /** 1106 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. 1107 * @dst: destination buffer 1108 * @src: bitmap to copy 1109 * @nbits: number of bits in the bitmap 1110 * 1111 * Require nbits % BITS_PER_LONG == 0. 1112 */ 1113 #ifdef __BIG_ENDIAN 1114 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits) 1115 { 1116 unsigned int i; 1117 1118 for (i = 0; i < nbits/BITS_PER_LONG; i++) { 1119 if (BITS_PER_LONG == 64) 1120 dst[i] = cpu_to_le64(src[i]); 1121 else 1122 dst[i] = cpu_to_le32(src[i]); 1123 } 1124 } 1125 EXPORT_SYMBOL(bitmap_copy_le); 1126 #endif 1127 1128 #if BITS_PER_LONG == 64 1129 /** 1130 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap 1131 * @bitmap: array of unsigned longs, the destination bitmap 1132 * @buf: array of u32 (in host byte order), the source bitmap 1133 * @nbits: number of bits in @bitmap 1134 */ 1135 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, 1136 unsigned int nbits) 1137 { 1138 unsigned int i, halfwords; 1139 1140 if (!nbits) 1141 return; 1142 1143 halfwords = DIV_ROUND_UP(nbits, 32); 1144 for (i = 0; i < halfwords; i++) { 1145 bitmap[i/2] = (unsigned long) buf[i]; 1146 if (++i < halfwords) 1147 bitmap[i/2] |= ((unsigned long) buf[i]) << 32; 1148 } 1149 1150 /* Clear tail bits in last word beyond nbits. */ 1151 if (nbits % BITS_PER_LONG) 1152 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits); 1153 } 1154 EXPORT_SYMBOL(bitmap_from_arr32); 1155 1156 /** 1157 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits 1158 * @buf: array of u32 (in host byte order), the dest bitmap 1159 * @bitmap: array of unsigned longs, the source bitmap 1160 * @nbits: number of bits in @bitmap 1161 */ 1162 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits) 1163 { 1164 unsigned int i, halfwords; 1165 1166 if (!nbits) 1167 return; 1168 1169 halfwords = DIV_ROUND_UP(nbits, 32); 1170 for (i = 0; i < halfwords; i++) { 1171 buf[i] = (u32) (bitmap[i/2] & UINT_MAX); 1172 if (++i < halfwords) 1173 buf[i] = (u32) (bitmap[i/2] >> 32); 1174 } 1175 1176 /* Clear tail bits in last element of array beyond nbits. */ 1177 if (nbits % BITS_PER_LONG) 1178 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31)); 1179 } 1180 EXPORT_SYMBOL(bitmap_to_arr32); 1181 1182 #endif 1183