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