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