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/mm.h>
17 #include <linux/slab.h>
18 #include <linux/string.h>
19 #include <linux/uaccess.h>
20 
21 #include <asm/page.h>
22 
23 /**
24  * DOC: bitmap introduction
25  *
26  * bitmaps provide an array of bits, implemented using an an
27  * array of unsigned longs.  The number of valid bits in a
28  * given bitmap does _not_ need to be an exact multiple of
29  * BITS_PER_LONG.
30  *
31  * The possible unused bits in the last, partially used word
32  * of a bitmap are 'don't care'.  The implementation makes
33  * no particular effort to keep them zero.  It ensures that
34  * their value will not affect the results of any operation.
35  * The bitmap operations that return Boolean (bitmap_empty,
36  * for example) or scalar (bitmap_weight, for example) results
37  * carefully filter out these unused bits from impacting their
38  * results.
39  *
40  * These operations actually hold to a slightly stronger rule:
41  * if you don't input any bitmaps to these ops that have some
42  * unused bits set, then they won't output any set unused bits
43  * in output bitmaps.
44  *
45  * The byte ordering of bitmaps is more natural on little
46  * endian architectures.  See the big-endian headers
47  * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
48  * for the best explanations of this ordering.
49  */
50 
__bitmap_equal(const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)51 int __bitmap_equal(const unsigned long *bitmap1,
52 		const unsigned long *bitmap2, unsigned int bits)
53 {
54 	unsigned int k, lim = bits/BITS_PER_LONG;
55 	for (k = 0; k < lim; ++k)
56 		if (bitmap1[k] != bitmap2[k])
57 			return 0;
58 
59 	if (bits % BITS_PER_LONG)
60 		if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
61 			return 0;
62 
63 	return 1;
64 }
65 EXPORT_SYMBOL(__bitmap_equal);
66 
__bitmap_complement(unsigned long * dst,const unsigned long * src,unsigned int bits)67 void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
68 {
69 	unsigned int k, lim = BITS_TO_LONGS(bits);
70 	for (k = 0; k < lim; ++k)
71 		dst[k] = ~src[k];
72 }
73 EXPORT_SYMBOL(__bitmap_complement);
74 
75 /**
76  * __bitmap_shift_right - logical right shift of the bits in a bitmap
77  *   @dst : destination bitmap
78  *   @src : source bitmap
79  *   @shift : shift by this many bits
80  *   @nbits : bitmap size, in bits
81  *
82  * Shifting right (dividing) means moving bits in the MS -> LS bit
83  * direction.  Zeros are fed into the vacated MS positions and the
84  * LS bits shifted off the bottom are lost.
85  */
__bitmap_shift_right(unsigned long * dst,const unsigned long * src,unsigned shift,unsigned nbits)86 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
87 			unsigned shift, unsigned nbits)
88 {
89 	unsigned k, lim = BITS_TO_LONGS(nbits);
90 	unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
91 	unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
92 	for (k = 0; off + k < lim; ++k) {
93 		unsigned long upper, lower;
94 
95 		/*
96 		 * If shift is not word aligned, take lower rem bits of
97 		 * word above and make them the top rem bits of result.
98 		 */
99 		if (!rem || off + k + 1 >= lim)
100 			upper = 0;
101 		else {
102 			upper = src[off + k + 1];
103 			if (off + k + 1 == lim - 1)
104 				upper &= mask;
105 			upper <<= (BITS_PER_LONG - rem);
106 		}
107 		lower = src[off + k];
108 		if (off + k == lim - 1)
109 			lower &= mask;
110 		lower >>= rem;
111 		dst[k] = lower | upper;
112 	}
113 	if (off)
114 		memset(&dst[lim - off], 0, off*sizeof(unsigned long));
115 }
116 EXPORT_SYMBOL(__bitmap_shift_right);
117 
118 
119 /**
120  * __bitmap_shift_left - logical left shift of the bits in a bitmap
121  *   @dst : destination bitmap
122  *   @src : source bitmap
123  *   @shift : shift by this many bits
124  *   @nbits : bitmap size, in bits
125  *
126  * Shifting left (multiplying) means moving bits in the LS -> MS
127  * direction.  Zeros are fed into the vacated LS bit positions
128  * and those MS bits shifted off the top are lost.
129  */
130 
__bitmap_shift_left(unsigned long * dst,const unsigned long * src,unsigned int shift,unsigned int nbits)131 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
132 			unsigned int shift, unsigned int nbits)
133 {
134 	int k;
135 	unsigned int lim = BITS_TO_LONGS(nbits);
136 	unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
137 	for (k = lim - off - 1; k >= 0; --k) {
138 		unsigned long upper, lower;
139 
140 		/*
141 		 * If shift is not word aligned, take upper rem bits of
142 		 * word below and make them the bottom rem bits of result.
143 		 */
144 		if (rem && k > 0)
145 			lower = src[k - 1] >> (BITS_PER_LONG - rem);
146 		else
147 			lower = 0;
148 		upper = src[k] << rem;
149 		dst[k + off] = lower | upper;
150 	}
151 	if (off)
152 		memset(dst, 0, off*sizeof(unsigned long));
153 }
154 EXPORT_SYMBOL(__bitmap_shift_left);
155 
__bitmap_and(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)156 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
157 				const unsigned long *bitmap2, unsigned int bits)
158 {
159 	unsigned int k;
160 	unsigned int lim = bits/BITS_PER_LONG;
161 	unsigned long result = 0;
162 
163 	for (k = 0; k < lim; k++)
164 		result |= (dst[k] = bitmap1[k] & bitmap2[k]);
165 	if (bits % BITS_PER_LONG)
166 		result |= (dst[k] = bitmap1[k] & bitmap2[k] &
167 			   BITMAP_LAST_WORD_MASK(bits));
168 	return result != 0;
169 }
170 EXPORT_SYMBOL(__bitmap_and);
171 
__bitmap_or(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)172 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
173 				const unsigned long *bitmap2, unsigned int bits)
174 {
175 	unsigned int k;
176 	unsigned int nr = BITS_TO_LONGS(bits);
177 
178 	for (k = 0; k < nr; k++)
179 		dst[k] = bitmap1[k] | bitmap2[k];
180 }
181 EXPORT_SYMBOL(__bitmap_or);
182 
__bitmap_xor(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)183 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
184 				const unsigned long *bitmap2, unsigned int bits)
185 {
186 	unsigned int k;
187 	unsigned int nr = BITS_TO_LONGS(bits);
188 
189 	for (k = 0; k < nr; k++)
190 		dst[k] = bitmap1[k] ^ bitmap2[k];
191 }
192 EXPORT_SYMBOL(__bitmap_xor);
193 
__bitmap_andnot(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)194 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
195 				const unsigned long *bitmap2, unsigned int bits)
196 {
197 	unsigned int k;
198 	unsigned int lim = bits/BITS_PER_LONG;
199 	unsigned long result = 0;
200 
201 	for (k = 0; k < lim; k++)
202 		result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
203 	if (bits % BITS_PER_LONG)
204 		result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
205 			   BITMAP_LAST_WORD_MASK(bits));
206 	return result != 0;
207 }
208 EXPORT_SYMBOL(__bitmap_andnot);
209 
__bitmap_intersects(const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)210 int __bitmap_intersects(const unsigned long *bitmap1,
211 			const unsigned long *bitmap2, unsigned int bits)
212 {
213 	unsigned int k, lim = bits/BITS_PER_LONG;
214 	for (k = 0; k < lim; ++k)
215 		if (bitmap1[k] & bitmap2[k])
216 			return 1;
217 
218 	if (bits % BITS_PER_LONG)
219 		if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
220 			return 1;
221 	return 0;
222 }
223 EXPORT_SYMBOL(__bitmap_intersects);
224 
__bitmap_subset(const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)225 int __bitmap_subset(const unsigned long *bitmap1,
226 		    const unsigned long *bitmap2, unsigned int bits)
227 {
228 	unsigned int k, lim = bits/BITS_PER_LONG;
229 	for (k = 0; k < lim; ++k)
230 		if (bitmap1[k] & ~bitmap2[k])
231 			return 0;
232 
233 	if (bits % BITS_PER_LONG)
234 		if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
235 			return 0;
236 	return 1;
237 }
238 EXPORT_SYMBOL(__bitmap_subset);
239 
__bitmap_weight(const unsigned long * bitmap,unsigned int bits)240 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
241 {
242 	unsigned int k, lim = bits/BITS_PER_LONG;
243 	int w = 0;
244 
245 	for (k = 0; k < lim; k++)
246 		w += hweight_long(bitmap[k]);
247 
248 	if (bits % BITS_PER_LONG)
249 		w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
250 
251 	return w;
252 }
253 EXPORT_SYMBOL(__bitmap_weight);
254 
__bitmap_set(unsigned long * map,unsigned int start,int len)255 void __bitmap_set(unsigned long *map, unsigned int start, int len)
256 {
257 	unsigned long *p = map + BIT_WORD(start);
258 	const unsigned int size = start + len;
259 	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
260 	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
261 
262 	while (len - bits_to_set >= 0) {
263 		*p |= mask_to_set;
264 		len -= bits_to_set;
265 		bits_to_set = BITS_PER_LONG;
266 		mask_to_set = ~0UL;
267 		p++;
268 	}
269 	if (len) {
270 		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
271 		*p |= mask_to_set;
272 	}
273 }
274 EXPORT_SYMBOL(__bitmap_set);
275 
__bitmap_clear(unsigned long * map,unsigned int start,int len)276 void __bitmap_clear(unsigned long *map, unsigned int start, int len)
277 {
278 	unsigned long *p = map + BIT_WORD(start);
279 	const unsigned int size = start + len;
280 	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
281 	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
282 
283 	while (len - bits_to_clear >= 0) {
284 		*p &= ~mask_to_clear;
285 		len -= bits_to_clear;
286 		bits_to_clear = BITS_PER_LONG;
287 		mask_to_clear = ~0UL;
288 		p++;
289 	}
290 	if (len) {
291 		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
292 		*p &= ~mask_to_clear;
293 	}
294 }
295 EXPORT_SYMBOL(__bitmap_clear);
296 
297 /**
298  * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
299  * @map: The address to base the search on
300  * @size: The bitmap size in bits
301  * @start: The bitnumber to start searching at
302  * @nr: The number of zeroed bits we're looking for
303  * @align_mask: Alignment mask for zero area
304  * @align_offset: Alignment offset for zero area.
305  *
306  * The @align_mask should be one less than a power of 2; the effect is that
307  * the bit offset of all zero areas this function finds plus @align_offset
308  * is multiple of that power of 2.
309  */
bitmap_find_next_zero_area_off(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,unsigned long align_mask,unsigned long align_offset)310 unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
311 					     unsigned long size,
312 					     unsigned long start,
313 					     unsigned int nr,
314 					     unsigned long align_mask,
315 					     unsigned long align_offset)
316 {
317 	unsigned long index, end, i;
318 again:
319 	index = find_next_zero_bit(map, size, start);
320 
321 	/* Align allocation */
322 	index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
323 
324 	end = index + nr;
325 	if (end > size)
326 		return end;
327 	i = find_next_bit(map, end, index);
328 	if (i < end) {
329 		start = i + 1;
330 		goto again;
331 	}
332 	return index;
333 }
334 EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
335 
336 /*
337  * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
338  * second version by Paul Jackson, third by Joe Korty.
339  */
340 
341 #define CHUNKSZ				32
342 #define nbits_to_hold_value(val)	fls(val)
343 #define BASEDEC 10		/* fancier cpuset lists input in decimal */
344 
345 /**
346  * __bitmap_parse - convert an ASCII hex string into a bitmap.
347  * @buf: pointer to buffer containing string.
348  * @buflen: buffer size in bytes.  If string is smaller than this
349  *    then it must be terminated with a \0.
350  * @is_user: location of buffer, 0 indicates kernel space
351  * @maskp: pointer to bitmap array that will contain result.
352  * @nmaskbits: size of bitmap, in bits.
353  *
354  * Commas group hex digits into chunks.  Each chunk defines exactly 32
355  * bits of the resultant bitmask.  No chunk may specify a value larger
356  * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
357  * then leading 0-bits are prepended.  %-EINVAL is returned for illegal
358  * characters and for grouping errors such as "1,,5", ",44", "," and "".
359  * Leading and trailing whitespace accepted, but not embedded whitespace.
360  */
__bitmap_parse(const char * buf,unsigned int buflen,int is_user,unsigned long * maskp,int nmaskbits)361 int __bitmap_parse(const char *buf, unsigned int buflen,
362 		int is_user, unsigned long *maskp,
363 		int nmaskbits)
364 {
365 	int c, old_c, totaldigits, ndigits, nchunks, nbits;
366 	u32 chunk;
367 	const char __user __force *ubuf = (const char __user __force *)buf;
368 
369 	bitmap_zero(maskp, nmaskbits);
370 
371 	nchunks = nbits = totaldigits = c = 0;
372 	do {
373 		chunk = 0;
374 		ndigits = totaldigits;
375 
376 		/* Get the next chunk of the bitmap */
377 		while (buflen) {
378 			old_c = c;
379 			if (is_user) {
380 				if (__get_user(c, ubuf++))
381 					return -EFAULT;
382 			}
383 			else
384 				c = *buf++;
385 			buflen--;
386 			if (isspace(c))
387 				continue;
388 
389 			/*
390 			 * If the last character was a space and the current
391 			 * character isn't '\0', we've got embedded whitespace.
392 			 * This is a no-no, so throw an error.
393 			 */
394 			if (totaldigits && c && isspace(old_c))
395 				return -EINVAL;
396 
397 			/* A '\0' or a ',' signal the end of the chunk */
398 			if (c == '\0' || c == ',')
399 				break;
400 
401 			if (!isxdigit(c))
402 				return -EINVAL;
403 
404 			/*
405 			 * Make sure there are at least 4 free bits in 'chunk'.
406 			 * If not, this hexdigit will overflow 'chunk', so
407 			 * throw an error.
408 			 */
409 			if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
410 				return -EOVERFLOW;
411 
412 			chunk = (chunk << 4) | hex_to_bin(c);
413 			totaldigits++;
414 		}
415 		if (ndigits == totaldigits)
416 			return -EINVAL;
417 		if (nchunks == 0 && chunk == 0)
418 			continue;
419 
420 		__bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
421 		*maskp |= chunk;
422 		nchunks++;
423 		nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
424 		if (nbits > nmaskbits)
425 			return -EOVERFLOW;
426 	} while (buflen && c == ',');
427 
428 	return 0;
429 }
430 EXPORT_SYMBOL(__bitmap_parse);
431 
432 /**
433  * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
434  *
435  * @ubuf: pointer to user buffer containing string.
436  * @ulen: buffer size in bytes.  If string is smaller than this
437  *    then it must be terminated with a \0.
438  * @maskp: pointer to bitmap array that will contain result.
439  * @nmaskbits: size of bitmap, in bits.
440  *
441  * Wrapper for __bitmap_parse(), providing it with user buffer.
442  *
443  * We cannot have this as an inline function in bitmap.h because it needs
444  * linux/uaccess.h to get the access_ok() declaration and this causes
445  * cyclic dependencies.
446  */
bitmap_parse_user(const char __user * ubuf,unsigned int ulen,unsigned long * maskp,int nmaskbits)447 int bitmap_parse_user(const char __user *ubuf,
448 			unsigned int ulen, unsigned long *maskp,
449 			int nmaskbits)
450 {
451 	if (!access_ok(VERIFY_READ, ubuf, ulen))
452 		return -EFAULT;
453 	return __bitmap_parse((const char __force *)ubuf,
454 				ulen, 1, maskp, nmaskbits);
455 
456 }
457 EXPORT_SYMBOL(bitmap_parse_user);
458 
459 /**
460  * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
461  * @list: indicates whether the bitmap must be list
462  * @buf: page aligned buffer into which string is placed
463  * @maskp: pointer to bitmap to convert
464  * @nmaskbits: size of bitmap, in bits
465  *
466  * Output format is a comma-separated list of decimal numbers and
467  * ranges if list is specified or hex digits grouped into comma-separated
468  * sets of 8 digits/set. Returns the number of characters written to buf.
469  *
470  * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
471  * area and that sufficient storage remains at @buf to accommodate the
472  * bitmap_print_to_pagebuf() output. Returns the number of characters
473  * actually printed to @buf, excluding terminating '\0'.
474  */
bitmap_print_to_pagebuf(bool list,char * buf,const unsigned long * maskp,int nmaskbits)475 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
476 			    int nmaskbits)
477 {
478 	ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
479 	int n = 0;
480 
481 	if (len > 1)
482 		n = list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
483 			   scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
484 	return n;
485 }
486 EXPORT_SYMBOL(bitmap_print_to_pagebuf);
487 
488 /**
489  * __bitmap_parselist - convert list format ASCII string to bitmap
490  * @buf: read nul-terminated user string from this buffer
491  * @buflen: buffer size in bytes.  If string is smaller than this
492  *    then it must be terminated with a \0.
493  * @is_user: location of buffer, 0 indicates kernel space
494  * @maskp: write resulting mask here
495  * @nmaskbits: number of bits in mask to be written
496  *
497  * Input format is a comma-separated list of decimal numbers and
498  * ranges.  Consecutively set bits are shown as two hyphen-separated
499  * decimal numbers, the smallest and largest bit numbers set in
500  * the range.
501  * Optionally each range can be postfixed to denote that only parts of it
502  * should be set. The range will divided to groups of specific size.
503  * From each group will be used only defined amount of bits.
504  * Syntax: range:used_size/group_size
505  * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
506  *
507  * Returns: 0 on success, -errno on invalid input strings. Error values:
508  *
509  *   - ``-EINVAL``: second number in range smaller than first
510  *   - ``-EINVAL``: invalid character in string
511  *   - ``-ERANGE``: bit number specified too large for mask
512  */
__bitmap_parselist(const char * buf,unsigned int buflen,int is_user,unsigned long * maskp,int nmaskbits)513 static int __bitmap_parselist(const char *buf, unsigned int buflen,
514 		int is_user, unsigned long *maskp,
515 		int nmaskbits)
516 {
517 	unsigned int a, b, old_a, old_b;
518 	unsigned int group_size, used_size, off;
519 	int c, old_c, totaldigits, ndigits;
520 	const char __user __force *ubuf = (const char __user __force *)buf;
521 	int at_start, in_range, in_partial_range;
522 
523 	totaldigits = c = 0;
524 	old_a = old_b = 0;
525 	group_size = used_size = 0;
526 	bitmap_zero(maskp, nmaskbits);
527 	do {
528 		at_start = 1;
529 		in_range = 0;
530 		in_partial_range = 0;
531 		a = b = 0;
532 		ndigits = totaldigits;
533 
534 		/* Get the next cpu# or a range of cpu#'s */
535 		while (buflen) {
536 			old_c = c;
537 			if (is_user) {
538 				if (__get_user(c, ubuf++))
539 					return -EFAULT;
540 			} else
541 				c = *buf++;
542 			buflen--;
543 			if (isspace(c))
544 				continue;
545 
546 			/* A '\0' or a ',' signal the end of a cpu# or range */
547 			if (c == '\0' || c == ',')
548 				break;
549 			/*
550 			* whitespaces between digits are not allowed,
551 			* but it's ok if whitespaces are on head or tail.
552 			* when old_c is whilespace,
553 			* if totaldigits == ndigits, whitespace is on head.
554 			* if whitespace is on tail, it should not run here.
555 			* as c was ',' or '\0',
556 			* the last code line has broken the current loop.
557 			*/
558 			if ((totaldigits != ndigits) && isspace(old_c))
559 				return -EINVAL;
560 
561 			if (c == '/') {
562 				used_size = a;
563 				at_start = 1;
564 				in_range = 0;
565 				a = b = 0;
566 				continue;
567 			}
568 
569 			if (c == ':') {
570 				old_a = a;
571 				old_b = b;
572 				at_start = 1;
573 				in_range = 0;
574 				in_partial_range = 1;
575 				a = b = 0;
576 				continue;
577 			}
578 
579 			if (c == '-') {
580 				if (at_start || in_range)
581 					return -EINVAL;
582 				b = 0;
583 				in_range = 1;
584 				at_start = 1;
585 				continue;
586 			}
587 
588 			if (!isdigit(c))
589 				return -EINVAL;
590 
591 			b = b * 10 + (c - '0');
592 			if (!in_range)
593 				a = b;
594 			at_start = 0;
595 			totaldigits++;
596 		}
597 		if (ndigits == totaldigits)
598 			continue;
599 		if (in_partial_range) {
600 			group_size = a;
601 			a = old_a;
602 			b = old_b;
603 			old_a = old_b = 0;
604 		} else {
605 			used_size = group_size = b - a + 1;
606 		}
607 		/* if no digit is after '-', it's wrong*/
608 		if (at_start && in_range)
609 			return -EINVAL;
610 		if (!(a <= b) || group_size == 0 || !(used_size <= group_size))
611 			return -EINVAL;
612 		if (b >= nmaskbits)
613 			return -ERANGE;
614 		while (a <= b) {
615 			off = min(b - a + 1, used_size);
616 			bitmap_set(maskp, a, off);
617 			a += group_size;
618 		}
619 	} while (buflen && c == ',');
620 	return 0;
621 }
622 
bitmap_parselist(const char * bp,unsigned long * maskp,int nmaskbits)623 int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
624 {
625 	char *nl  = strchrnul(bp, '\n');
626 	int len = nl - bp;
627 
628 	return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
629 }
630 EXPORT_SYMBOL(bitmap_parselist);
631 
632 
633 /**
634  * bitmap_parselist_user()
635  *
636  * @ubuf: pointer to user buffer containing string.
637  * @ulen: buffer size in bytes.  If string is smaller than this
638  *    then it must be terminated with a \0.
639  * @maskp: pointer to bitmap array that will contain result.
640  * @nmaskbits: size of bitmap, in bits.
641  *
642  * Wrapper for bitmap_parselist(), providing it with user buffer.
643  *
644  * We cannot have this as an inline function in bitmap.h because it needs
645  * linux/uaccess.h to get the access_ok() declaration and this causes
646  * cyclic dependencies.
647  */
bitmap_parselist_user(const char __user * ubuf,unsigned int ulen,unsigned long * maskp,int nmaskbits)648 int bitmap_parselist_user(const char __user *ubuf,
649 			unsigned int ulen, unsigned long *maskp,
650 			int nmaskbits)
651 {
652 	if (!access_ok(VERIFY_READ, ubuf, ulen))
653 		return -EFAULT;
654 	return __bitmap_parselist((const char __force *)ubuf,
655 					ulen, 1, maskp, nmaskbits);
656 }
657 EXPORT_SYMBOL(bitmap_parselist_user);
658 
659 
660 /**
661  * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
662  *	@buf: pointer to a bitmap
663  *	@pos: a bit position in @buf (0 <= @pos < @nbits)
664  *	@nbits: number of valid bit positions in @buf
665  *
666  * Map the bit at position @pos in @buf (of length @nbits) to the
667  * ordinal of which set bit it is.  If it is not set or if @pos
668  * is not a valid bit position, map to -1.
669  *
670  * If for example, just bits 4 through 7 are set in @buf, then @pos
671  * values 4 through 7 will get mapped to 0 through 3, respectively,
672  * and other @pos values will get mapped to -1.  When @pos value 7
673  * gets mapped to (returns) @ord value 3 in this example, that means
674  * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
675  *
676  * The bit positions 0 through @bits are valid positions in @buf.
677  */
bitmap_pos_to_ord(const unsigned long * buf,unsigned int pos,unsigned int nbits)678 static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
679 {
680 	if (pos >= nbits || !test_bit(pos, buf))
681 		return -1;
682 
683 	return __bitmap_weight(buf, pos);
684 }
685 
686 /**
687  * bitmap_ord_to_pos - find position of n-th set bit in bitmap
688  *	@buf: pointer to bitmap
689  *	@ord: ordinal bit position (n-th set bit, n >= 0)
690  *	@nbits: number of valid bit positions in @buf
691  *
692  * Map the ordinal offset of bit @ord in @buf to its position in @buf.
693  * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
694  * >= weight(buf), returns @nbits.
695  *
696  * If for example, just bits 4 through 7 are set in @buf, then @ord
697  * values 0 through 3 will get mapped to 4 through 7, respectively,
698  * and all other @ord values returns @nbits.  When @ord value 3
699  * gets mapped to (returns) @pos value 7 in this example, that means
700  * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
701  *
702  * The bit positions 0 through @nbits-1 are valid positions in @buf.
703  */
bitmap_ord_to_pos(const unsigned long * buf,unsigned int ord,unsigned int nbits)704 unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
705 {
706 	unsigned int pos;
707 
708 	for (pos = find_first_bit(buf, nbits);
709 	     pos < nbits && ord;
710 	     pos = find_next_bit(buf, nbits, pos + 1))
711 		ord--;
712 
713 	return pos;
714 }
715 
716 /**
717  * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
718  *	@dst: remapped result
719  *	@src: subset to be remapped
720  *	@old: defines domain of map
721  *	@new: defines range of map
722  *	@nbits: number of bits in each of these bitmaps
723  *
724  * Let @old and @new define a mapping of bit positions, such that
725  * whatever position is held by the n-th set bit in @old is mapped
726  * to the n-th set bit in @new.  In the more general case, allowing
727  * for the possibility that the weight 'w' of @new is less than the
728  * weight of @old, map the position of the n-th set bit in @old to
729  * the position of the m-th set bit in @new, where m == n % w.
730  *
731  * If either of the @old and @new bitmaps are empty, or if @src and
732  * @dst point to the same location, then this routine copies @src
733  * to @dst.
734  *
735  * The positions of unset bits in @old are mapped to themselves
736  * (the identify map).
737  *
738  * Apply the above specified mapping to @src, placing the result in
739  * @dst, clearing any bits previously set in @dst.
740  *
741  * For example, lets say that @old has bits 4 through 7 set, and
742  * @new has bits 12 through 15 set.  This defines the mapping of bit
743  * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
744  * bit positions unchanged.  So if say @src comes into this routine
745  * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
746  * 13 and 15 set.
747  */
bitmap_remap(unsigned long * dst,const unsigned long * src,const unsigned long * old,const unsigned long * new,unsigned int nbits)748 void bitmap_remap(unsigned long *dst, const unsigned long *src,
749 		const unsigned long *old, const unsigned long *new,
750 		unsigned int nbits)
751 {
752 	unsigned int oldbit, w;
753 
754 	if (dst == src)		/* following doesn't handle inplace remaps */
755 		return;
756 	bitmap_zero(dst, nbits);
757 
758 	w = bitmap_weight(new, nbits);
759 	for_each_set_bit(oldbit, src, nbits) {
760 		int n = bitmap_pos_to_ord(old, oldbit, nbits);
761 
762 		if (n < 0 || w == 0)
763 			set_bit(oldbit, dst);	/* identity map */
764 		else
765 			set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst);
766 	}
767 }
768 EXPORT_SYMBOL(bitmap_remap);
769 
770 /**
771  * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
772  *	@oldbit: bit position to be mapped
773  *	@old: defines domain of map
774  *	@new: defines range of map
775  *	@bits: number of bits in each of these bitmaps
776  *
777  * Let @old and @new define a mapping of bit positions, such that
778  * whatever position is held by the n-th set bit in @old is mapped
779  * to the n-th set bit in @new.  In the more general case, allowing
780  * for the possibility that the weight 'w' of @new is less than the
781  * weight of @old, map the position of the n-th set bit in @old to
782  * the position of the m-th set bit in @new, where m == n % w.
783  *
784  * The positions of unset bits in @old are mapped to themselves
785  * (the identify map).
786  *
787  * Apply the above specified mapping to bit position @oldbit, returning
788  * the new bit position.
789  *
790  * For example, lets say that @old has bits 4 through 7 set, and
791  * @new has bits 12 through 15 set.  This defines the mapping of bit
792  * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
793  * bit positions unchanged.  So if say @oldbit is 5, then this routine
794  * returns 13.
795  */
bitmap_bitremap(int oldbit,const unsigned long * old,const unsigned long * new,int bits)796 int bitmap_bitremap(int oldbit, const unsigned long *old,
797 				const unsigned long *new, int bits)
798 {
799 	int w = bitmap_weight(new, bits);
800 	int n = bitmap_pos_to_ord(old, oldbit, bits);
801 	if (n < 0 || w == 0)
802 		return oldbit;
803 	else
804 		return bitmap_ord_to_pos(new, n % w, bits);
805 }
806 EXPORT_SYMBOL(bitmap_bitremap);
807 
808 /**
809  * bitmap_onto - translate one bitmap relative to another
810  *	@dst: resulting translated bitmap
811  * 	@orig: original untranslated bitmap
812  * 	@relmap: bitmap relative to which translated
813  *	@bits: number of bits in each of these bitmaps
814  *
815  * Set the n-th bit of @dst iff there exists some m such that the
816  * n-th bit of @relmap is set, the m-th bit of @orig is set, and
817  * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
818  * (If you understood the previous sentence the first time your
819  * read it, you're overqualified for your current job.)
820  *
821  * In other words, @orig is mapped onto (surjectively) @dst,
822  * using the map { <n, m> | the n-th bit of @relmap is the
823  * m-th set bit of @relmap }.
824  *
825  * Any set bits in @orig above bit number W, where W is the
826  * weight of (number of set bits in) @relmap are mapped nowhere.
827  * In particular, if for all bits m set in @orig, m >= W, then
828  * @dst will end up empty.  In situations where the possibility
829  * of such an empty result is not desired, one way to avoid it is
830  * to use the bitmap_fold() operator, below, to first fold the
831  * @orig bitmap over itself so that all its set bits x are in the
832  * range 0 <= x < W.  The bitmap_fold() operator does this by
833  * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
834  *
835  * Example [1] for bitmap_onto():
836  *  Let's say @relmap has bits 30-39 set, and @orig has bits
837  *  1, 3, 5, 7, 9 and 11 set.  Then on return from this routine,
838  *  @dst will have bits 31, 33, 35, 37 and 39 set.
839  *
840  *  When bit 0 is set in @orig, it means turn on the bit in
841  *  @dst corresponding to whatever is the first bit (if any)
842  *  that is turned on in @relmap.  Since bit 0 was off in the
843  *  above example, we leave off that bit (bit 30) in @dst.
844  *
845  *  When bit 1 is set in @orig (as in the above example), it
846  *  means turn on the bit in @dst corresponding to whatever
847  *  is the second bit that is turned on in @relmap.  The second
848  *  bit in @relmap that was turned on in the above example was
849  *  bit 31, so we turned on bit 31 in @dst.
850  *
851  *  Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
852  *  because they were the 4th, 6th, 8th and 10th set bits
853  *  set in @relmap, and the 4th, 6th, 8th and 10th bits of
854  *  @orig (i.e. bits 3, 5, 7 and 9) were also set.
855  *
856  *  When bit 11 is set in @orig, it means turn on the bit in
857  *  @dst corresponding to whatever is the twelfth bit that is
858  *  turned on in @relmap.  In the above example, there were
859  *  only ten bits turned on in @relmap (30..39), so that bit
860  *  11 was set in @orig had no affect on @dst.
861  *
862  * Example [2] for bitmap_fold() + bitmap_onto():
863  *  Let's say @relmap has these ten bits set::
864  *
865  *		40 41 42 43 45 48 53 61 74 95
866  *
867  *  (for the curious, that's 40 plus the first ten terms of the
868  *  Fibonacci sequence.)
869  *
870  *  Further lets say we use the following code, invoking
871  *  bitmap_fold() then bitmap_onto, as suggested above to
872  *  avoid the possibility of an empty @dst result::
873  *
874  *	unsigned long *tmp;	// a temporary bitmap's bits
875  *
876  *	bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
877  *	bitmap_onto(dst, tmp, relmap, bits);
878  *
879  *  Then this table shows what various values of @dst would be, for
880  *  various @orig's.  I list the zero-based positions of each set bit.
881  *  The tmp column shows the intermediate result, as computed by
882  *  using bitmap_fold() to fold the @orig bitmap modulo ten
883  *  (the weight of @relmap):
884  *
885  *      =============== ============== =================
886  *      @orig           tmp            @dst
887  *      0                0             40
888  *      1                1             41
889  *      9                9             95
890  *      10               0             40 [#f1]_
891  *      1 3 5 7          1 3 5 7       41 43 48 61
892  *      0 1 2 3 4        0 1 2 3 4     40 41 42 43 45
893  *      0 9 18 27        0 9 8 7       40 61 74 95
894  *      0 10 20 30       0             40
895  *      0 11 22 33       0 1 2 3       40 41 42 43
896  *      0 12 24 36       0 2 4 6       40 42 45 53
897  *      78 102 211       1 2 8         41 42 74 [#f1]_
898  *      =============== ============== =================
899  *
900  * .. [#f1]
901  *
902  *     For these marked lines, if we hadn't first done bitmap_fold()
903  *     into tmp, then the @dst result would have been empty.
904  *
905  * If either of @orig or @relmap is empty (no set bits), then @dst
906  * will be returned empty.
907  *
908  * If (as explained above) the only set bits in @orig are in positions
909  * m where m >= W, (where W is the weight of @relmap) then @dst will
910  * once again be returned empty.
911  *
912  * All bits in @dst not set by the above rule are cleared.
913  */
bitmap_onto(unsigned long * dst,const unsigned long * orig,const unsigned long * relmap,unsigned int bits)914 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
915 			const unsigned long *relmap, unsigned int bits)
916 {
917 	unsigned int n, m;	/* same meaning as in above comment */
918 
919 	if (dst == orig)	/* following doesn't handle inplace mappings */
920 		return;
921 	bitmap_zero(dst, bits);
922 
923 	/*
924 	 * The following code is a more efficient, but less
925 	 * obvious, equivalent to the loop:
926 	 *	for (m = 0; m < bitmap_weight(relmap, bits); m++) {
927 	 *		n = bitmap_ord_to_pos(orig, m, bits);
928 	 *		if (test_bit(m, orig))
929 	 *			set_bit(n, dst);
930 	 *	}
931 	 */
932 
933 	m = 0;
934 	for_each_set_bit(n, relmap, bits) {
935 		/* m == bitmap_pos_to_ord(relmap, n, bits) */
936 		if (test_bit(m, orig))
937 			set_bit(n, dst);
938 		m++;
939 	}
940 }
941 EXPORT_SYMBOL(bitmap_onto);
942 
943 /**
944  * bitmap_fold - fold larger bitmap into smaller, modulo specified size
945  *	@dst: resulting smaller bitmap
946  *	@orig: original larger bitmap
947  *	@sz: specified size
948  *	@nbits: number of bits in each of these bitmaps
949  *
950  * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
951  * Clear all other bits in @dst.  See further the comment and
952  * Example [2] for bitmap_onto() for why and how to use this.
953  */
bitmap_fold(unsigned long * dst,const unsigned long * orig,unsigned int sz,unsigned int nbits)954 void bitmap_fold(unsigned long *dst, const unsigned long *orig,
955 			unsigned int sz, unsigned int nbits)
956 {
957 	unsigned int oldbit;
958 
959 	if (dst == orig)	/* following doesn't handle inplace mappings */
960 		return;
961 	bitmap_zero(dst, nbits);
962 
963 	for_each_set_bit(oldbit, orig, nbits)
964 		set_bit(oldbit % sz, dst);
965 }
966 EXPORT_SYMBOL(bitmap_fold);
967 
968 /*
969  * Common code for bitmap_*_region() routines.
970  *	bitmap: array of unsigned longs corresponding to the bitmap
971  *	pos: the beginning of the region
972  *	order: region size (log base 2 of number of bits)
973  *	reg_op: operation(s) to perform on that region of bitmap
974  *
975  * Can set, verify and/or release a region of bits in a bitmap,
976  * depending on which combination of REG_OP_* flag bits is set.
977  *
978  * A region of a bitmap is a sequence of bits in the bitmap, of
979  * some size '1 << order' (a power of two), aligned to that same
980  * '1 << order' power of two.
981  *
982  * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
983  * Returns 0 in all other cases and reg_ops.
984  */
985 
986 enum {
987 	REG_OP_ISFREE,		/* true if region is all zero bits */
988 	REG_OP_ALLOC,		/* set all bits in region */
989 	REG_OP_RELEASE,		/* clear all bits in region */
990 };
991 
__reg_op(unsigned long * bitmap,unsigned int pos,int order,int reg_op)992 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
993 {
994 	int nbits_reg;		/* number of bits in region */
995 	int index;		/* index first long of region in bitmap */
996 	int offset;		/* bit offset region in bitmap[index] */
997 	int nlongs_reg;		/* num longs spanned by region in bitmap */
998 	int nbitsinlong;	/* num bits of region in each spanned long */
999 	unsigned long mask;	/* bitmask for one long of region */
1000 	int i;			/* scans bitmap by longs */
1001 	int ret = 0;		/* return value */
1002 
1003 	/*
1004 	 * Either nlongs_reg == 1 (for small orders that fit in one long)
1005 	 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1006 	 */
1007 	nbits_reg = 1 << order;
1008 	index = pos / BITS_PER_LONG;
1009 	offset = pos - (index * BITS_PER_LONG);
1010 	nlongs_reg = BITS_TO_LONGS(nbits_reg);
1011 	nbitsinlong = min(nbits_reg,  BITS_PER_LONG);
1012 
1013 	/*
1014 	 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1015 	 * overflows if nbitsinlong == BITS_PER_LONG.
1016 	 */
1017 	mask = (1UL << (nbitsinlong - 1));
1018 	mask += mask - 1;
1019 	mask <<= offset;
1020 
1021 	switch (reg_op) {
1022 	case REG_OP_ISFREE:
1023 		for (i = 0; i < nlongs_reg; i++) {
1024 			if (bitmap[index + i] & mask)
1025 				goto done;
1026 		}
1027 		ret = 1;	/* all bits in region free (zero) */
1028 		break;
1029 
1030 	case REG_OP_ALLOC:
1031 		for (i = 0; i < nlongs_reg; i++)
1032 			bitmap[index + i] |= mask;
1033 		break;
1034 
1035 	case REG_OP_RELEASE:
1036 		for (i = 0; i < nlongs_reg; i++)
1037 			bitmap[index + i] &= ~mask;
1038 		break;
1039 	}
1040 done:
1041 	return ret;
1042 }
1043 
1044 /**
1045  * bitmap_find_free_region - find a contiguous aligned mem region
1046  *	@bitmap: array of unsigned longs corresponding to the bitmap
1047  *	@bits: number of bits in the bitmap
1048  *	@order: region size (log base 2 of number of bits) to find
1049  *
1050  * Find a region of free (zero) bits in a @bitmap of @bits bits and
1051  * allocate them (set them to one).  Only consider regions of length
1052  * a power (@order) of two, aligned to that power of two, which
1053  * makes the search algorithm much faster.
1054  *
1055  * Return the bit offset in bitmap of the allocated region,
1056  * or -errno on failure.
1057  */
bitmap_find_free_region(unsigned long * bitmap,unsigned int bits,int order)1058 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1059 {
1060 	unsigned int pos, end;		/* scans bitmap by regions of size order */
1061 
1062 	for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1063 		if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1064 			continue;
1065 		__reg_op(bitmap, pos, order, REG_OP_ALLOC);
1066 		return pos;
1067 	}
1068 	return -ENOMEM;
1069 }
1070 EXPORT_SYMBOL(bitmap_find_free_region);
1071 
1072 /**
1073  * bitmap_release_region - release allocated bitmap region
1074  *	@bitmap: array of unsigned longs corresponding to the bitmap
1075  *	@pos: beginning of bit region to release
1076  *	@order: region size (log base 2 of number of bits) to release
1077  *
1078  * This is the complement to __bitmap_find_free_region() and releases
1079  * the found region (by clearing it in the bitmap).
1080  *
1081  * No return value.
1082  */
bitmap_release_region(unsigned long * bitmap,unsigned int pos,int order)1083 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1084 {
1085 	__reg_op(bitmap, pos, order, REG_OP_RELEASE);
1086 }
1087 EXPORT_SYMBOL(bitmap_release_region);
1088 
1089 /**
1090  * bitmap_allocate_region - allocate bitmap region
1091  *	@bitmap: array of unsigned longs corresponding to the bitmap
1092  *	@pos: beginning of bit region to allocate
1093  *	@order: region size (log base 2 of number of bits) to allocate
1094  *
1095  * Allocate (set bits in) a specified region of a bitmap.
1096  *
1097  * Return 0 on success, or %-EBUSY if specified region wasn't
1098  * free (not all bits were zero).
1099  */
bitmap_allocate_region(unsigned long * bitmap,unsigned int pos,int order)1100 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1101 {
1102 	if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1103 		return -EBUSY;
1104 	return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1105 }
1106 EXPORT_SYMBOL(bitmap_allocate_region);
1107 
1108 /**
1109  * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1110  * @dst:   destination buffer
1111  * @src:   bitmap to copy
1112  * @nbits: number of bits in the bitmap
1113  *
1114  * Require nbits % BITS_PER_LONG == 0.
1115  */
1116 #ifdef __BIG_ENDIAN
bitmap_copy_le(unsigned long * dst,const unsigned long * src,unsigned int nbits)1117 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
1118 {
1119 	unsigned int i;
1120 
1121 	for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1122 		if (BITS_PER_LONG == 64)
1123 			dst[i] = cpu_to_le64(src[i]);
1124 		else
1125 			dst[i] = cpu_to_le32(src[i]);
1126 	}
1127 }
1128 EXPORT_SYMBOL(bitmap_copy_le);
1129 #endif
1130 
bitmap_alloc(unsigned int nbits,gfp_t flags)1131 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
1132 {
1133 	return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
1134 			     flags);
1135 }
1136 EXPORT_SYMBOL(bitmap_alloc);
1137 
bitmap_zalloc(unsigned int nbits,gfp_t flags)1138 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
1139 {
1140 	return bitmap_alloc(nbits, flags | __GFP_ZERO);
1141 }
1142 EXPORT_SYMBOL(bitmap_zalloc);
1143 
bitmap_free(const unsigned long * bitmap)1144 void bitmap_free(const unsigned long *bitmap)
1145 {
1146 	kfree(bitmap);
1147 }
1148 EXPORT_SYMBOL(bitmap_free);
1149 
1150 #if BITS_PER_LONG == 64
1151 /**
1152  * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
1153  *	@bitmap: array of unsigned longs, the destination bitmap
1154  *	@buf: array of u32 (in host byte order), the source bitmap
1155  *	@nbits: number of bits in @bitmap
1156  */
bitmap_from_arr32(unsigned long * bitmap,const u32 * buf,unsigned int nbits)1157 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
1158 {
1159 	unsigned int i, halfwords;
1160 
1161 	halfwords = DIV_ROUND_UP(nbits, 32);
1162 	for (i = 0; i < halfwords; i++) {
1163 		bitmap[i/2] = (unsigned long) buf[i];
1164 		if (++i < halfwords)
1165 			bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
1166 	}
1167 
1168 	/* Clear tail bits in last word beyond nbits. */
1169 	if (nbits % BITS_PER_LONG)
1170 		bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
1171 }
1172 EXPORT_SYMBOL(bitmap_from_arr32);
1173 
1174 /**
1175  * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
1176  *	@buf: array of u32 (in host byte order), the dest bitmap
1177  *	@bitmap: array of unsigned longs, the source bitmap
1178  *	@nbits: number of bits in @bitmap
1179  */
bitmap_to_arr32(u32 * buf,const unsigned long * bitmap,unsigned int nbits)1180 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
1181 {
1182 	unsigned int i, halfwords;
1183 
1184 	halfwords = DIV_ROUND_UP(nbits, 32);
1185 	for (i = 0; i < halfwords; i++) {
1186 		buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
1187 		if (++i < halfwords)
1188 			buf[i] = (u32) (bitmap[i/2] >> 32);
1189 	}
1190 
1191 	/* Clear tail bits in last element of array beyond nbits. */
1192 	if (nbits % BITS_PER_LONG)
1193 		buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
1194 }
1195 EXPORT_SYMBOL(bitmap_to_arr32);
1196 
1197 #endif
1198