xref: /openbmc/linux/lib/bitmap.c (revision 275876e2)
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