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, unsigned int bits) 44 { 45 unsigned 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, unsigned int bits) 59 { 60 unsigned 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, unsigned int bits) 75 { 76 unsigned 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, unsigned int bits) 90 { 91 unsigned 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]; 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, unsigned int bits) 186 { 187 unsigned int k; 188 unsigned int lim = bits/BITS_PER_LONG; 189 unsigned long result = 0; 190 191 for (k = 0; k < lim; k++) 192 result |= (dst[k] = bitmap1[k] & bitmap2[k]); 193 if (bits % BITS_PER_LONG) 194 result |= (dst[k] = bitmap1[k] & bitmap2[k] & 195 BITMAP_LAST_WORD_MASK(bits)); 196 return result != 0; 197 } 198 EXPORT_SYMBOL(__bitmap_and); 199 200 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, 201 const unsigned long *bitmap2, unsigned int bits) 202 { 203 unsigned int k; 204 unsigned int nr = BITS_TO_LONGS(bits); 205 206 for (k = 0; k < nr; k++) 207 dst[k] = bitmap1[k] | bitmap2[k]; 208 } 209 EXPORT_SYMBOL(__bitmap_or); 210 211 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, 212 const unsigned long *bitmap2, unsigned int bits) 213 { 214 unsigned int k; 215 unsigned int nr = BITS_TO_LONGS(bits); 216 217 for (k = 0; k < nr; k++) 218 dst[k] = bitmap1[k] ^ bitmap2[k]; 219 } 220 EXPORT_SYMBOL(__bitmap_xor); 221 222 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, 223 const unsigned long *bitmap2, unsigned int bits) 224 { 225 unsigned int k; 226 unsigned int lim = bits/BITS_PER_LONG; 227 unsigned long result = 0; 228 229 for (k = 0; k < lim; k++) 230 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); 231 if (bits % BITS_PER_LONG) 232 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] & 233 BITMAP_LAST_WORD_MASK(bits)); 234 return result != 0; 235 } 236 EXPORT_SYMBOL(__bitmap_andnot); 237 238 int __bitmap_intersects(const unsigned long *bitmap1, 239 const unsigned long *bitmap2, unsigned int bits) 240 { 241 unsigned int k, lim = bits/BITS_PER_LONG; 242 for (k = 0; k < lim; ++k) 243 if (bitmap1[k] & bitmap2[k]) 244 return 1; 245 246 if (bits % BITS_PER_LONG) 247 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 248 return 1; 249 return 0; 250 } 251 EXPORT_SYMBOL(__bitmap_intersects); 252 253 int __bitmap_subset(const unsigned long *bitmap1, 254 const unsigned long *bitmap2, unsigned int bits) 255 { 256 unsigned int k, lim = bits/BITS_PER_LONG; 257 for (k = 0; k < lim; ++k) 258 if (bitmap1[k] & ~bitmap2[k]) 259 return 0; 260 261 if (bits % BITS_PER_LONG) 262 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) 263 return 0; 264 return 1; 265 } 266 EXPORT_SYMBOL(__bitmap_subset); 267 268 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) 269 { 270 unsigned int k, lim = bits/BITS_PER_LONG; 271 int w = 0; 272 273 for (k = 0; k < lim; k++) 274 w += hweight_long(bitmap[k]); 275 276 if (bits % BITS_PER_LONG) 277 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); 278 279 return w; 280 } 281 EXPORT_SYMBOL(__bitmap_weight); 282 283 void bitmap_set(unsigned long *map, unsigned int start, int len) 284 { 285 unsigned long *p = map + BIT_WORD(start); 286 const unsigned int size = start + len; 287 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); 288 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); 289 290 while (len - bits_to_set >= 0) { 291 *p |= mask_to_set; 292 len -= bits_to_set; 293 bits_to_set = BITS_PER_LONG; 294 mask_to_set = ~0UL; 295 p++; 296 } 297 if (len) { 298 mask_to_set &= BITMAP_LAST_WORD_MASK(size); 299 *p |= mask_to_set; 300 } 301 } 302 EXPORT_SYMBOL(bitmap_set); 303 304 void bitmap_clear(unsigned long *map, unsigned int start, int len) 305 { 306 unsigned long *p = map + BIT_WORD(start); 307 const unsigned int size = start + len; 308 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); 309 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); 310 311 while (len - bits_to_clear >= 0) { 312 *p &= ~mask_to_clear; 313 len -= bits_to_clear; 314 bits_to_clear = BITS_PER_LONG; 315 mask_to_clear = ~0UL; 316 p++; 317 } 318 if (len) { 319 mask_to_clear &= BITMAP_LAST_WORD_MASK(size); 320 *p &= ~mask_to_clear; 321 } 322 } 323 EXPORT_SYMBOL(bitmap_clear); 324 325 /* 326 * bitmap_find_next_zero_area - find a contiguous aligned zero area 327 * @map: The address to base the search on 328 * @size: The bitmap size in bits 329 * @start: The bitnumber to start searching at 330 * @nr: The number of zeroed bits we're looking for 331 * @align_mask: Alignment mask for zero area 332 * 333 * The @align_mask should be one less than a power of 2; the effect is that 334 * the bit offset of all zero areas this function finds is multiples of that 335 * power of 2. A @align_mask of 0 means no alignment is required. 336 */ 337 unsigned long bitmap_find_next_zero_area(unsigned long *map, 338 unsigned long size, 339 unsigned long start, 340 unsigned int nr, 341 unsigned long align_mask) 342 { 343 unsigned long index, end, i; 344 again: 345 index = find_next_zero_bit(map, size, start); 346 347 /* Align allocation */ 348 index = __ALIGN_MASK(index, align_mask); 349 350 end = index + nr; 351 if (end > size) 352 return end; 353 i = find_next_bit(map, end, index); 354 if (i < end) { 355 start = i + 1; 356 goto again; 357 } 358 return index; 359 } 360 EXPORT_SYMBOL(bitmap_find_next_zero_area); 361 362 /* 363 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers, 364 * second version by Paul Jackson, third by Joe Korty. 365 */ 366 367 #define CHUNKSZ 32 368 #define nbits_to_hold_value(val) fls(val) 369 #define BASEDEC 10 /* fancier cpuset lists input in decimal */ 370 371 /** 372 * bitmap_scnprintf - convert bitmap to an ASCII hex string. 373 * @buf: byte buffer into which string is placed 374 * @buflen: reserved size of @buf, in bytes 375 * @maskp: pointer to bitmap to convert 376 * @nmaskbits: size of bitmap, in bits 377 * 378 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into 379 * comma-separated sets of eight digits per set. Returns the number of 380 * characters which were written to *buf, excluding the trailing \0. 381 */ 382 int bitmap_scnprintf(char *buf, unsigned int buflen, 383 const unsigned long *maskp, int nmaskbits) 384 { 385 int i, word, bit, len = 0; 386 unsigned long val; 387 const char *sep = ""; 388 int chunksz; 389 u32 chunkmask; 390 391 chunksz = nmaskbits & (CHUNKSZ - 1); 392 if (chunksz == 0) 393 chunksz = CHUNKSZ; 394 395 i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ; 396 for (; i >= 0; i -= CHUNKSZ) { 397 chunkmask = ((1ULL << chunksz) - 1); 398 word = i / BITS_PER_LONG; 399 bit = i % BITS_PER_LONG; 400 val = (maskp[word] >> bit) & chunkmask; 401 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep, 402 (chunksz+3)/4, val); 403 chunksz = CHUNKSZ; 404 sep = ","; 405 } 406 return len; 407 } 408 EXPORT_SYMBOL(bitmap_scnprintf); 409 410 /** 411 * __bitmap_parse - convert an ASCII hex string into a bitmap. 412 * @buf: pointer to buffer containing string. 413 * @buflen: buffer size in bytes. If string is smaller than this 414 * then it must be terminated with a \0. 415 * @is_user: location of buffer, 0 indicates kernel space 416 * @maskp: pointer to bitmap array that will contain result. 417 * @nmaskbits: size of bitmap, in bits. 418 * 419 * Commas group hex digits into chunks. Each chunk defines exactly 32 420 * bits of the resultant bitmask. No chunk may specify a value larger 421 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value 422 * then leading 0-bits are prepended. %-EINVAL is returned for illegal 423 * characters and for grouping errors such as "1,,5", ",44", "," and "". 424 * Leading and trailing whitespace accepted, but not embedded whitespace. 425 */ 426 int __bitmap_parse(const char *buf, unsigned int buflen, 427 int is_user, unsigned long *maskp, 428 int nmaskbits) 429 { 430 int c, old_c, totaldigits, ndigits, nchunks, nbits; 431 u32 chunk; 432 const char __user __force *ubuf = (const char __user __force *)buf; 433 434 bitmap_zero(maskp, nmaskbits); 435 436 nchunks = nbits = totaldigits = c = 0; 437 do { 438 chunk = ndigits = 0; 439 440 /* Get the next chunk of the bitmap */ 441 while (buflen) { 442 old_c = c; 443 if (is_user) { 444 if (__get_user(c, ubuf++)) 445 return -EFAULT; 446 } 447 else 448 c = *buf++; 449 buflen--; 450 if (isspace(c)) 451 continue; 452 453 /* 454 * If the last character was a space and the current 455 * character isn't '\0', we've got embedded whitespace. 456 * This is a no-no, so throw an error. 457 */ 458 if (totaldigits && c && isspace(old_c)) 459 return -EINVAL; 460 461 /* A '\0' or a ',' signal the end of the chunk */ 462 if (c == '\0' || c == ',') 463 break; 464 465 if (!isxdigit(c)) 466 return -EINVAL; 467 468 /* 469 * Make sure there are at least 4 free bits in 'chunk'. 470 * If not, this hexdigit will overflow 'chunk', so 471 * throw an error. 472 */ 473 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) 474 return -EOVERFLOW; 475 476 chunk = (chunk << 4) | hex_to_bin(c); 477 ndigits++; totaldigits++; 478 } 479 if (ndigits == 0) 480 return -EINVAL; 481 if (nchunks == 0 && chunk == 0) 482 continue; 483 484 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); 485 *maskp |= chunk; 486 nchunks++; 487 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; 488 if (nbits > nmaskbits) 489 return -EOVERFLOW; 490 } while (buflen && c == ','); 491 492 return 0; 493 } 494 EXPORT_SYMBOL(__bitmap_parse); 495 496 /** 497 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap 498 * 499 * @ubuf: pointer to user buffer containing string. 500 * @ulen: buffer size in bytes. If string is smaller than this 501 * then it must be terminated with a \0. 502 * @maskp: pointer to bitmap array that will contain result. 503 * @nmaskbits: size of bitmap, in bits. 504 * 505 * Wrapper for __bitmap_parse(), providing it with user buffer. 506 * 507 * We cannot have this as an inline function in bitmap.h because it needs 508 * linux/uaccess.h to get the access_ok() declaration and this causes 509 * cyclic dependencies. 510 */ 511 int bitmap_parse_user(const char __user *ubuf, 512 unsigned int ulen, unsigned long *maskp, 513 int nmaskbits) 514 { 515 if (!access_ok(VERIFY_READ, ubuf, ulen)) 516 return -EFAULT; 517 return __bitmap_parse((const char __force *)ubuf, 518 ulen, 1, maskp, nmaskbits); 519 520 } 521 EXPORT_SYMBOL(bitmap_parse_user); 522 523 /* 524 * bscnl_emit(buf, buflen, rbot, rtop, bp) 525 * 526 * Helper routine for bitmap_scnlistprintf(). Write decimal number 527 * or range to buf, suppressing output past buf+buflen, with optional 528 * comma-prefix. Return len of what was written to *buf, excluding the 529 * trailing \0. 530 */ 531 static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len) 532 { 533 if (len > 0) 534 len += scnprintf(buf + len, buflen - len, ","); 535 if (rbot == rtop) 536 len += scnprintf(buf + len, buflen - len, "%d", rbot); 537 else 538 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop); 539 return len; 540 } 541 542 /** 543 * bitmap_scnlistprintf - convert bitmap to list format ASCII string 544 * @buf: byte buffer into which string is placed 545 * @buflen: reserved size of @buf, in bytes 546 * @maskp: pointer to bitmap to convert 547 * @nmaskbits: size of bitmap, in bits 548 * 549 * Output format is a comma-separated list of decimal numbers and 550 * ranges. Consecutively set bits are shown as two hyphen-separated 551 * decimal numbers, the smallest and largest bit numbers set in 552 * the range. Output format is compatible with the format 553 * accepted as input by bitmap_parselist(). 554 * 555 * The return value is the number of characters which were written to *buf 556 * excluding the trailing '\0', as per ISO C99's scnprintf. 557 */ 558 int bitmap_scnlistprintf(char *buf, unsigned int buflen, 559 const unsigned long *maskp, int nmaskbits) 560 { 561 int len = 0; 562 /* current bit is 'cur', most recently seen range is [rbot, rtop] */ 563 int cur, rbot, rtop; 564 565 if (buflen == 0) 566 return 0; 567 buf[0] = 0; 568 569 rbot = cur = find_first_bit(maskp, nmaskbits); 570 while (cur < nmaskbits) { 571 rtop = cur; 572 cur = find_next_bit(maskp, nmaskbits, cur+1); 573 if (cur >= nmaskbits || cur > rtop + 1) { 574 len = bscnl_emit(buf, buflen, rbot, rtop, len); 575 rbot = cur; 576 } 577 } 578 return len; 579 } 580 EXPORT_SYMBOL(bitmap_scnlistprintf); 581 582 /** 583 * __bitmap_parselist - convert list format ASCII string to bitmap 584 * @buf: read nul-terminated user string from this buffer 585 * @buflen: buffer size in bytes. If string is smaller than this 586 * then it must be terminated with a \0. 587 * @is_user: location of buffer, 0 indicates kernel space 588 * @maskp: write resulting mask here 589 * @nmaskbits: number of bits in mask to be written 590 * 591 * Input format is a comma-separated list of decimal numbers and 592 * ranges. Consecutively set bits are shown as two hyphen-separated 593 * decimal numbers, the smallest and largest bit numbers set in 594 * the range. 595 * 596 * Returns 0 on success, -errno on invalid input strings. 597 * Error values: 598 * %-EINVAL: second number in range smaller than first 599 * %-EINVAL: invalid character in string 600 * %-ERANGE: bit number specified too large for mask 601 */ 602 static int __bitmap_parselist(const char *buf, unsigned int buflen, 603 int is_user, unsigned long *maskp, 604 int nmaskbits) 605 { 606 unsigned a, b; 607 int c, old_c, totaldigits; 608 const char __user __force *ubuf = (const char __user __force *)buf; 609 int exp_digit, in_range; 610 611 totaldigits = c = 0; 612 bitmap_zero(maskp, nmaskbits); 613 do { 614 exp_digit = 1; 615 in_range = 0; 616 a = b = 0; 617 618 /* Get the next cpu# or a range of cpu#'s */ 619 while (buflen) { 620 old_c = c; 621 if (is_user) { 622 if (__get_user(c, ubuf++)) 623 return -EFAULT; 624 } else 625 c = *buf++; 626 buflen--; 627 if (isspace(c)) 628 continue; 629 630 /* 631 * If the last character was a space and the current 632 * character isn't '\0', we've got embedded whitespace. 633 * This is a no-no, so throw an error. 634 */ 635 if (totaldigits && c && isspace(old_c)) 636 return -EINVAL; 637 638 /* A '\0' or a ',' signal the end of a cpu# or range */ 639 if (c == '\0' || c == ',') 640 break; 641 642 if (c == '-') { 643 if (exp_digit || in_range) 644 return -EINVAL; 645 b = 0; 646 in_range = 1; 647 exp_digit = 1; 648 continue; 649 } 650 651 if (!isdigit(c)) 652 return -EINVAL; 653 654 b = b * 10 + (c - '0'); 655 if (!in_range) 656 a = b; 657 exp_digit = 0; 658 totaldigits++; 659 } 660 if (!(a <= b)) 661 return -EINVAL; 662 if (b >= nmaskbits) 663 return -ERANGE; 664 while (a <= b) { 665 set_bit(a, maskp); 666 a++; 667 } 668 } while (buflen && c == ','); 669 return 0; 670 } 671 672 int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) 673 { 674 char *nl = strchrnul(bp, '\n'); 675 int len = nl - bp; 676 677 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits); 678 } 679 EXPORT_SYMBOL(bitmap_parselist); 680 681 682 /** 683 * bitmap_parselist_user() 684 * 685 * @ubuf: pointer to user buffer containing string. 686 * @ulen: buffer size in bytes. If string is smaller than this 687 * then it must be terminated with a \0. 688 * @maskp: pointer to bitmap array that will contain result. 689 * @nmaskbits: size of bitmap, in bits. 690 * 691 * Wrapper for bitmap_parselist(), providing it with user buffer. 692 * 693 * We cannot have this as an inline function in bitmap.h because it needs 694 * linux/uaccess.h to get the access_ok() declaration and this causes 695 * cyclic dependencies. 696 */ 697 int bitmap_parselist_user(const char __user *ubuf, 698 unsigned int ulen, unsigned long *maskp, 699 int nmaskbits) 700 { 701 if (!access_ok(VERIFY_READ, ubuf, ulen)) 702 return -EFAULT; 703 return __bitmap_parselist((const char __force *)ubuf, 704 ulen, 1, maskp, nmaskbits); 705 } 706 EXPORT_SYMBOL(bitmap_parselist_user); 707 708 709 /** 710 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap 711 * @buf: pointer to a bitmap 712 * @pos: a bit position in @buf (0 <= @pos < @bits) 713 * @bits: number of valid bit positions in @buf 714 * 715 * Map the bit at position @pos in @buf (of length @bits) to the 716 * ordinal of which set bit it is. If it is not set or if @pos 717 * is not a valid bit position, map to -1. 718 * 719 * If for example, just bits 4 through 7 are set in @buf, then @pos 720 * values 4 through 7 will get mapped to 0 through 3, respectively, 721 * and other @pos values will get mapped to -1. When @pos value 7 722 * gets mapped to (returns) @ord value 3 in this example, that means 723 * that bit 7 is the 3rd (starting with 0th) set bit in @buf. 724 * 725 * The bit positions 0 through @bits are valid positions in @buf. 726 */ 727 static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits) 728 { 729 int i, ord; 730 731 if (pos < 0 || pos >= bits || !test_bit(pos, buf)) 732 return -1; 733 734 i = find_first_bit(buf, bits); 735 ord = 0; 736 while (i < pos) { 737 i = find_next_bit(buf, bits, i + 1); 738 ord++; 739 } 740 BUG_ON(i != pos); 741 742 return ord; 743 } 744 745 /** 746 * bitmap_ord_to_pos - find position of n-th set bit in bitmap 747 * @buf: pointer to bitmap 748 * @ord: ordinal bit position (n-th set bit, n >= 0) 749 * @bits: number of valid bit positions in @buf 750 * 751 * Map the ordinal offset of bit @ord in @buf to its position in @buf. 752 * Value of @ord should be in range 0 <= @ord < weight(buf), else 753 * results are undefined. 754 * 755 * If for example, just bits 4 through 7 are set in @buf, then @ord 756 * values 0 through 3 will get mapped to 4 through 7, respectively, 757 * and all other @ord values return undefined values. When @ord value 3 758 * gets mapped to (returns) @pos value 7 in this example, that means 759 * that the 3rd set bit (starting with 0th) is at position 7 in @buf. 760 * 761 * The bit positions 0 through @bits are valid positions in @buf. 762 */ 763 int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) 764 { 765 int pos = 0; 766 767 if (ord >= 0 && ord < bits) { 768 int i; 769 770 for (i = find_first_bit(buf, bits); 771 i < bits && ord > 0; 772 i = find_next_bit(buf, bits, i + 1)) 773 ord--; 774 if (i < bits && ord == 0) 775 pos = i; 776 } 777 778 return pos; 779 } 780 781 /** 782 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap 783 * @dst: remapped result 784 * @src: subset to be remapped 785 * @old: defines domain of map 786 * @new: defines range of map 787 * @bits: number of bits in each of these bitmaps 788 * 789 * Let @old and @new define a mapping of bit positions, such that 790 * whatever position is held by the n-th set bit in @old is mapped 791 * to the n-th set bit in @new. In the more general case, allowing 792 * for the possibility that the weight 'w' of @new is less than the 793 * weight of @old, map the position of the n-th set bit in @old to 794 * the position of the m-th set bit in @new, where m == n % w. 795 * 796 * If either of the @old and @new bitmaps are empty, or if @src and 797 * @dst point to the same location, then this routine copies @src 798 * to @dst. 799 * 800 * The positions of unset bits in @old are mapped to themselves 801 * (the identify map). 802 * 803 * Apply the above specified mapping to @src, placing the result in 804 * @dst, clearing any bits previously set in @dst. 805 * 806 * For example, lets say that @old has bits 4 through 7 set, and 807 * @new has bits 12 through 15 set. This defines the mapping of bit 808 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 809 * bit positions unchanged. So if say @src comes into this routine 810 * with bits 1, 5 and 7 set, then @dst should leave with bits 1, 811 * 13 and 15 set. 812 */ 813 void bitmap_remap(unsigned long *dst, const unsigned long *src, 814 const unsigned long *old, const unsigned long *new, 815 int bits) 816 { 817 int oldbit, w; 818 819 if (dst == src) /* following doesn't handle inplace remaps */ 820 return; 821 bitmap_zero(dst, bits); 822 823 w = bitmap_weight(new, bits); 824 for_each_set_bit(oldbit, src, bits) { 825 int n = bitmap_pos_to_ord(old, oldbit, bits); 826 827 if (n < 0 || w == 0) 828 set_bit(oldbit, dst); /* identity map */ 829 else 830 set_bit(bitmap_ord_to_pos(new, n % w, bits), dst); 831 } 832 } 833 EXPORT_SYMBOL(bitmap_remap); 834 835 /** 836 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit 837 * @oldbit: bit position to be mapped 838 * @old: defines domain of map 839 * @new: defines range of map 840 * @bits: number of bits in each of these bitmaps 841 * 842 * Let @old and @new define a mapping of bit positions, such that 843 * whatever position is held by the n-th set bit in @old is mapped 844 * to the n-th set bit in @new. In the more general case, allowing 845 * for the possibility that the weight 'w' of @new is less than the 846 * weight of @old, map the position of the n-th set bit in @old to 847 * the position of the m-th set bit in @new, where m == n % w. 848 * 849 * The positions of unset bits in @old are mapped to themselves 850 * (the identify map). 851 * 852 * Apply the above specified mapping to bit position @oldbit, returning 853 * the new bit position. 854 * 855 * For example, lets say that @old has bits 4 through 7 set, and 856 * @new has bits 12 through 15 set. This defines the mapping of bit 857 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other 858 * bit positions unchanged. So if say @oldbit is 5, then this routine 859 * returns 13. 860 */ 861 int bitmap_bitremap(int oldbit, const unsigned long *old, 862 const unsigned long *new, int bits) 863 { 864 int w = bitmap_weight(new, bits); 865 int n = bitmap_pos_to_ord(old, oldbit, bits); 866 if (n < 0 || w == 0) 867 return oldbit; 868 else 869 return bitmap_ord_to_pos(new, n % w, bits); 870 } 871 EXPORT_SYMBOL(bitmap_bitremap); 872 873 /** 874 * bitmap_onto - translate one bitmap relative to another 875 * @dst: resulting translated bitmap 876 * @orig: original untranslated bitmap 877 * @relmap: bitmap relative to which translated 878 * @bits: number of bits in each of these bitmaps 879 * 880 * Set the n-th bit of @dst iff there exists some m such that the 881 * n-th bit of @relmap is set, the m-th bit of @orig is set, and 882 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. 883 * (If you understood the previous sentence the first time your 884 * read it, you're overqualified for your current job.) 885 * 886 * In other words, @orig is mapped onto (surjectively) @dst, 887 * using the the map { <n, m> | the n-th bit of @relmap is the 888 * m-th set bit of @relmap }. 889 * 890 * Any set bits in @orig above bit number W, where W is the 891 * weight of (number of set bits in) @relmap are mapped nowhere. 892 * In particular, if for all bits m set in @orig, m >= W, then 893 * @dst will end up empty. In situations where the possibility 894 * of such an empty result is not desired, one way to avoid it is 895 * to use the bitmap_fold() operator, below, to first fold the 896 * @orig bitmap over itself so that all its set bits x are in the 897 * range 0 <= x < W. The bitmap_fold() operator does this by 898 * setting the bit (m % W) in @dst, for each bit (m) set in @orig. 899 * 900 * Example [1] for bitmap_onto(): 901 * Let's say @relmap has bits 30-39 set, and @orig has bits 902 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, 903 * @dst will have bits 31, 33, 35, 37 and 39 set. 904 * 905 * When bit 0 is set in @orig, it means turn on the bit in 906 * @dst corresponding to whatever is the first bit (if any) 907 * that is turned on in @relmap. Since bit 0 was off in the 908 * above example, we leave off that bit (bit 30) in @dst. 909 * 910 * When bit 1 is set in @orig (as in the above example), it 911 * means turn on the bit in @dst corresponding to whatever 912 * is the second bit that is turned on in @relmap. The second 913 * bit in @relmap that was turned on in the above example was 914 * bit 31, so we turned on bit 31 in @dst. 915 * 916 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, 917 * because they were the 4th, 6th, 8th and 10th set bits 918 * set in @relmap, and the 4th, 6th, 8th and 10th bits of 919 * @orig (i.e. bits 3, 5, 7 and 9) were also set. 920 * 921 * When bit 11 is set in @orig, it means turn on the bit in 922 * @dst corresponding to whatever is the twelfth bit that is 923 * turned on in @relmap. In the above example, there were 924 * only ten bits turned on in @relmap (30..39), so that bit 925 * 11 was set in @orig had no affect on @dst. 926 * 927 * Example [2] for bitmap_fold() + bitmap_onto(): 928 * Let's say @relmap has these ten bits set: 929 * 40 41 42 43 45 48 53 61 74 95 930 * (for the curious, that's 40 plus the first ten terms of the 931 * Fibonacci sequence.) 932 * 933 * Further lets say we use the following code, invoking 934 * bitmap_fold() then bitmap_onto, as suggested above to 935 * avoid the possitility of an empty @dst result: 936 * 937 * unsigned long *tmp; // a temporary bitmap's bits 938 * 939 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); 940 * bitmap_onto(dst, tmp, relmap, bits); 941 * 942 * Then this table shows what various values of @dst would be, for 943 * various @orig's. I list the zero-based positions of each set bit. 944 * The tmp column shows the intermediate result, as computed by 945 * using bitmap_fold() to fold the @orig bitmap modulo ten 946 * (the weight of @relmap). 947 * 948 * @orig tmp @dst 949 * 0 0 40 950 * 1 1 41 951 * 9 9 95 952 * 10 0 40 (*) 953 * 1 3 5 7 1 3 5 7 41 43 48 61 954 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 955 * 0 9 18 27 0 9 8 7 40 61 74 95 956 * 0 10 20 30 0 40 957 * 0 11 22 33 0 1 2 3 40 41 42 43 958 * 0 12 24 36 0 2 4 6 40 42 45 53 959 * 78 102 211 1 2 8 41 42 74 (*) 960 * 961 * (*) For these marked lines, if we hadn't first done bitmap_fold() 962 * into tmp, then the @dst result would have been empty. 963 * 964 * If either of @orig or @relmap is empty (no set bits), then @dst 965 * will be returned empty. 966 * 967 * If (as explained above) the only set bits in @orig are in positions 968 * m where m >= W, (where W is the weight of @relmap) then @dst will 969 * once again be returned empty. 970 * 971 * All bits in @dst not set by the above rule are cleared. 972 */ 973 void bitmap_onto(unsigned long *dst, const unsigned long *orig, 974 const unsigned long *relmap, int bits) 975 { 976 int n, m; /* same meaning as in above comment */ 977 978 if (dst == orig) /* following doesn't handle inplace mappings */ 979 return; 980 bitmap_zero(dst, bits); 981 982 /* 983 * The following code is a more efficient, but less 984 * obvious, equivalent to the loop: 985 * for (m = 0; m < bitmap_weight(relmap, bits); m++) { 986 * n = bitmap_ord_to_pos(orig, m, bits); 987 * if (test_bit(m, orig)) 988 * set_bit(n, dst); 989 * } 990 */ 991 992 m = 0; 993 for_each_set_bit(n, relmap, bits) { 994 /* m == bitmap_pos_to_ord(relmap, n, bits) */ 995 if (test_bit(m, orig)) 996 set_bit(n, dst); 997 m++; 998 } 999 } 1000 EXPORT_SYMBOL(bitmap_onto); 1001 1002 /** 1003 * bitmap_fold - fold larger bitmap into smaller, modulo specified size 1004 * @dst: resulting smaller bitmap 1005 * @orig: original larger bitmap 1006 * @sz: specified size 1007 * @bits: number of bits in each of these bitmaps 1008 * 1009 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. 1010 * Clear all other bits in @dst. See further the comment and 1011 * Example [2] for bitmap_onto() for why and how to use this. 1012 */ 1013 void bitmap_fold(unsigned long *dst, const unsigned long *orig, 1014 int sz, int bits) 1015 { 1016 int oldbit; 1017 1018 if (dst == orig) /* following doesn't handle inplace mappings */ 1019 return; 1020 bitmap_zero(dst, bits); 1021 1022 for_each_set_bit(oldbit, orig, bits) 1023 set_bit(oldbit % sz, dst); 1024 } 1025 EXPORT_SYMBOL(bitmap_fold); 1026 1027 /* 1028 * Common code for bitmap_*_region() routines. 1029 * bitmap: array of unsigned longs corresponding to the bitmap 1030 * pos: the beginning of the region 1031 * order: region size (log base 2 of number of bits) 1032 * reg_op: operation(s) to perform on that region of bitmap 1033 * 1034 * Can set, verify and/or release a region of bits in a bitmap, 1035 * depending on which combination of REG_OP_* flag bits is set. 1036 * 1037 * A region of a bitmap is a sequence of bits in the bitmap, of 1038 * some size '1 << order' (a power of two), aligned to that same 1039 * '1 << order' power of two. 1040 * 1041 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). 1042 * Returns 0 in all other cases and reg_ops. 1043 */ 1044 1045 enum { 1046 REG_OP_ISFREE, /* true if region is all zero bits */ 1047 REG_OP_ALLOC, /* set all bits in region */ 1048 REG_OP_RELEASE, /* clear all bits in region */ 1049 }; 1050 1051 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op) 1052 { 1053 int nbits_reg; /* number of bits in region */ 1054 int index; /* index first long of region in bitmap */ 1055 int offset; /* bit offset region in bitmap[index] */ 1056 int nlongs_reg; /* num longs spanned by region in bitmap */ 1057 int nbitsinlong; /* num bits of region in each spanned long */ 1058 unsigned long mask; /* bitmask for one long of region */ 1059 int i; /* scans bitmap by longs */ 1060 int ret = 0; /* return value */ 1061 1062 /* 1063 * Either nlongs_reg == 1 (for small orders that fit in one long) 1064 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) 1065 */ 1066 nbits_reg = 1 << order; 1067 index = pos / BITS_PER_LONG; 1068 offset = pos - (index * BITS_PER_LONG); 1069 nlongs_reg = BITS_TO_LONGS(nbits_reg); 1070 nbitsinlong = min(nbits_reg, BITS_PER_LONG); 1071 1072 /* 1073 * Can't do "mask = (1UL << nbitsinlong) - 1", as that 1074 * overflows if nbitsinlong == BITS_PER_LONG. 1075 */ 1076 mask = (1UL << (nbitsinlong - 1)); 1077 mask += mask - 1; 1078 mask <<= offset; 1079 1080 switch (reg_op) { 1081 case REG_OP_ISFREE: 1082 for (i = 0; i < nlongs_reg; i++) { 1083 if (bitmap[index + i] & mask) 1084 goto done; 1085 } 1086 ret = 1; /* all bits in region free (zero) */ 1087 break; 1088 1089 case REG_OP_ALLOC: 1090 for (i = 0; i < nlongs_reg; i++) 1091 bitmap[index + i] |= mask; 1092 break; 1093 1094 case REG_OP_RELEASE: 1095 for (i = 0; i < nlongs_reg; i++) 1096 bitmap[index + i] &= ~mask; 1097 break; 1098 } 1099 done: 1100 return ret; 1101 } 1102 1103 /** 1104 * bitmap_find_free_region - find a contiguous aligned mem region 1105 * @bitmap: array of unsigned longs corresponding to the bitmap 1106 * @bits: number of bits in the bitmap 1107 * @order: region size (log base 2 of number of bits) to find 1108 * 1109 * Find a region of free (zero) bits in a @bitmap of @bits bits and 1110 * allocate them (set them to one). Only consider regions of length 1111 * a power (@order) of two, aligned to that power of two, which 1112 * makes the search algorithm much faster. 1113 * 1114 * Return the bit offset in bitmap of the allocated region, 1115 * or -errno on failure. 1116 */ 1117 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order) 1118 { 1119 unsigned int pos, end; /* scans bitmap by regions of size order */ 1120 1121 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) { 1122 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1123 continue; 1124 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1125 return pos; 1126 } 1127 return -ENOMEM; 1128 } 1129 EXPORT_SYMBOL(bitmap_find_free_region); 1130 1131 /** 1132 * bitmap_release_region - release allocated bitmap region 1133 * @bitmap: array of unsigned longs corresponding to the bitmap 1134 * @pos: beginning of bit region to release 1135 * @order: region size (log base 2 of number of bits) to release 1136 * 1137 * This is the complement to __bitmap_find_free_region() and releases 1138 * the found region (by clearing it in the bitmap). 1139 * 1140 * No return value. 1141 */ 1142 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order) 1143 { 1144 __reg_op(bitmap, pos, order, REG_OP_RELEASE); 1145 } 1146 EXPORT_SYMBOL(bitmap_release_region); 1147 1148 /** 1149 * bitmap_allocate_region - allocate bitmap region 1150 * @bitmap: array of unsigned longs corresponding to the bitmap 1151 * @pos: beginning of bit region to allocate 1152 * @order: region size (log base 2 of number of bits) to allocate 1153 * 1154 * Allocate (set bits in) a specified region of a bitmap. 1155 * 1156 * Return 0 on success, or %-EBUSY if specified region wasn't 1157 * free (not all bits were zero). 1158 */ 1159 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order) 1160 { 1161 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 1162 return -EBUSY; 1163 return __reg_op(bitmap, pos, order, REG_OP_ALLOC); 1164 } 1165 EXPORT_SYMBOL(bitmap_allocate_region); 1166 1167 /** 1168 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. 1169 * @dst: destination buffer 1170 * @src: bitmap to copy 1171 * @nbits: number of bits in the bitmap 1172 * 1173 * Require nbits % BITS_PER_LONG == 0. 1174 */ 1175 void bitmap_copy_le(void *dst, const unsigned long *src, int nbits) 1176 { 1177 unsigned long *d = dst; 1178 int i; 1179 1180 for (i = 0; i < nbits/BITS_PER_LONG; i++) { 1181 if (BITS_PER_LONG == 64) 1182 d[i] = cpu_to_le64(src[i]); 1183 else 1184 d[i] = cpu_to_le32(src[i]); 1185 } 1186 } 1187 EXPORT_SYMBOL(bitmap_copy_le); 1188