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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -05008#include <linux/export.h>
9#include <linux/thread_info.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010#include <linux/ctype.h>
11#include <linux/errno.h>
12#include <linux/bitmap.h>
13#include <linux/bitops.h>
Paul Gortmaker50af5ea2012-01-20 18:35:53 -050014#include <linux/bug.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#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
43int __bitmap_empty(const unsigned long *bitmap, int bits)
44{
45 int k, lim = bits/BITS_PER_LONG;
46 for (k = 0; k < lim; ++k)
47 if (bitmap[k])
48 return 0;
49
50 if (bits % BITS_PER_LONG)
51 if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
52 return 0;
53
54 return 1;
55}
56EXPORT_SYMBOL(__bitmap_empty);
57
58int __bitmap_full(const unsigned long *bitmap, int bits)
59{
60 int k, lim = bits/BITS_PER_LONG;
61 for (k = 0; k < lim; ++k)
62 if (~bitmap[k])
63 return 0;
64
65 if (bits % BITS_PER_LONG)
66 if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
67 return 0;
68
69 return 1;
70}
71EXPORT_SYMBOL(__bitmap_full);
72
73int __bitmap_equal(const unsigned long *bitmap1,
74 const unsigned long *bitmap2, int bits)
75{
76 int k, lim = bits/BITS_PER_LONG;
77 for (k = 0; k < lim; ++k)
78 if (bitmap1[k] != bitmap2[k])
79 return 0;
80
81 if (bits % BITS_PER_LONG)
82 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
83 return 0;
84
85 return 1;
86}
87EXPORT_SYMBOL(__bitmap_equal);
88
89void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
90{
91 int k, lim = bits/BITS_PER_LONG;
92 for (k = 0; k < lim; ++k)
93 dst[k] = ~src[k];
94
95 if (bits % BITS_PER_LONG)
96 dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
97}
98EXPORT_SYMBOL(__bitmap_complement);
99
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800100/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 * __bitmap_shift_right - logical right shift of the bits in a bitmap
Randy Dunlap05fb6bf2007-02-28 20:12:13 -0800102 * @dst : destination bitmap
103 * @src : source bitmap
104 * @shift : shift by this many bits
105 * @bits : bitmap size, in bits
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 *
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 */
111void __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}
141EXPORT_SYMBOL(__bitmap_shift_right);
142
143
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800144/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 * __bitmap_shift_left - logical left shift of the bits in a bitmap
Randy Dunlap05fb6bf2007-02-28 20:12:13 -0800146 * @dst : destination bitmap
147 * @src : source bitmap
148 * @shift : shift by this many bits
149 * @bits : bitmap size, in bits
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 *
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
156void __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}
182EXPORT_SYMBOL(__bitmap_shift_left);
183
Linus Torvaldsf4b03732009-08-21 09:26:15 -0700184int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 const unsigned long *bitmap2, int bits)
186{
187 int k;
188 int nr = BITS_TO_LONGS(bits);
Linus Torvaldsf4b03732009-08-21 09:26:15 -0700189 unsigned long result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
191 for (k = 0; k < nr; k++)
Linus Torvaldsf4b03732009-08-21 09:26:15 -0700192 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
193 return result != 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194}
195EXPORT_SYMBOL(__bitmap_and);
196
197void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
198 const unsigned long *bitmap2, int bits)
199{
200 int k;
201 int nr = BITS_TO_LONGS(bits);
202
203 for (k = 0; k < nr; k++)
204 dst[k] = bitmap1[k] | bitmap2[k];
205}
206EXPORT_SYMBOL(__bitmap_or);
207
208void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
209 const unsigned long *bitmap2, int bits)
210{
211 int k;
212 int nr = BITS_TO_LONGS(bits);
213
214 for (k = 0; k < nr; k++)
215 dst[k] = bitmap1[k] ^ bitmap2[k];
216}
217EXPORT_SYMBOL(__bitmap_xor);
218
Linus Torvaldsf4b03732009-08-21 09:26:15 -0700219int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 const unsigned long *bitmap2, int bits)
221{
222 int k;
223 int nr = BITS_TO_LONGS(bits);
Linus Torvaldsf4b03732009-08-21 09:26:15 -0700224 unsigned long result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
226 for (k = 0; k < nr; k++)
Linus Torvaldsf4b03732009-08-21 09:26:15 -0700227 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
228 return result != 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229}
230EXPORT_SYMBOL(__bitmap_andnot);
231
232int __bitmap_intersects(const unsigned long *bitmap1,
233 const unsigned long *bitmap2, int bits)
234{
235 int k, lim = bits/BITS_PER_LONG;
236 for (k = 0; k < lim; ++k)
237 if (bitmap1[k] & bitmap2[k])
238 return 1;
239
240 if (bits % BITS_PER_LONG)
241 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
242 return 1;
243 return 0;
244}
245EXPORT_SYMBOL(__bitmap_intersects);
246
247int __bitmap_subset(const unsigned long *bitmap1,
248 const unsigned long *bitmap2, int bits)
249{
250 int k, lim = bits/BITS_PER_LONG;
251 for (k = 0; k < lim; ++k)
252 if (bitmap1[k] & ~bitmap2[k])
253 return 0;
254
255 if (bits % BITS_PER_LONG)
256 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
257 return 0;
258 return 1;
259}
260EXPORT_SYMBOL(__bitmap_subset);
261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262int __bitmap_weight(const unsigned long *bitmap, int bits)
263{
264 int k, w = 0, lim = bits/BITS_PER_LONG;
265
266 for (k = 0; k < lim; k++)
Akinobu Mita37d54112006-03-26 01:39:56 -0800267 w += hweight_long(bitmap[k]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
269 if (bits % BITS_PER_LONG)
Akinobu Mita37d54112006-03-26 01:39:56 -0800270 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
272 return w;
273}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274EXPORT_SYMBOL(__bitmap_weight);
275
Akinobu Mitac1a2a962009-12-15 16:48:25 -0800276void bitmap_set(unsigned long *map, int start, int nr)
277{
278 unsigned long *p = map + BIT_WORD(start);
279 const int size = start + nr;
280 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
281 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
282
283 while (nr - bits_to_set >= 0) {
284 *p |= mask_to_set;
285 nr -= bits_to_set;
286 bits_to_set = BITS_PER_LONG;
287 mask_to_set = ~0UL;
288 p++;
289 }
290 if (nr) {
291 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
292 *p |= mask_to_set;
293 }
294}
295EXPORT_SYMBOL(bitmap_set);
296
297void bitmap_clear(unsigned long *map, int start, int nr)
298{
299 unsigned long *p = map + BIT_WORD(start);
300 const int size = start + nr;
301 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
302 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
303
304 while (nr - bits_to_clear >= 0) {
305 *p &= ~mask_to_clear;
306 nr -= bits_to_clear;
307 bits_to_clear = BITS_PER_LONG;
308 mask_to_clear = ~0UL;
309 p++;
310 }
311 if (nr) {
312 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
313 *p &= ~mask_to_clear;
314 }
315}
316EXPORT_SYMBOL(bitmap_clear);
317
Bryan Huntsman3f2bc4d2011-08-16 17:27:22 -0700318/**
Akinobu Mitac1a2a962009-12-15 16:48:25 -0800319 * bitmap_find_next_zero_area - find a contiguous aligned zero area
320 * @map: The address to base the search on
321 * @size: The bitmap size in bits
322 * @start: The bitnumber to start searching at
323 * @nr: The number of zeroed bits we're looking for
324 * @align_mask: Alignment mask for zero area
Bryan Huntsman3f2bc4d2011-08-16 17:27:22 -0700325 * @align_offset: Alignment offset for zero area.
Akinobu Mitac1a2a962009-12-15 16:48:25 -0800326 *
327 * The @align_mask should be one less than a power of 2; the effect is that
Bryan Huntsman3f2bc4d2011-08-16 17:27:22 -0700328 * the bit offset of all zero areas this function finds plus @align_offset
329 * is multiple of that power of 2.
Akinobu Mitac1a2a962009-12-15 16:48:25 -0800330 */
Bryan Huntsman3f2bc4d2011-08-16 17:27:22 -0700331unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
332 unsigned long size,
333 unsigned long start,
334 unsigned int nr,
335 unsigned long align_mask,
336 unsigned long align_offset)
Akinobu Mitac1a2a962009-12-15 16:48:25 -0800337{
338 unsigned long index, end, i;
339again:
340 index = find_next_zero_bit(map, size, start);
341
342 /* Align allocation */
Bryan Huntsman3f2bc4d2011-08-16 17:27:22 -0700343 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
Akinobu Mitac1a2a962009-12-15 16:48:25 -0800344
345 end = index + nr;
346 if (end > size)
347 return end;
348 i = find_next_bit(map, end, index);
349 if (i < end) {
350 start = i + 1;
351 goto again;
352 }
353 return index;
354}
Bryan Huntsman3f2bc4d2011-08-16 17:27:22 -0700355EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
Akinobu Mitac1a2a962009-12-15 16:48:25 -0800356
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357/*
358 * Bitmap printing & parsing functions: first version by Bill Irwin,
359 * second version by Paul Jackson, third by Joe Korty.
360 */
361
362#define CHUNKSZ 32
363#define nbits_to_hold_value(val) fls(val)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364#define BASEDEC 10 /* fancier cpuset lists input in decimal */
365
366/**
367 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
368 * @buf: byte buffer into which string is placed
369 * @buflen: reserved size of @buf, in bytes
370 * @maskp: pointer to bitmap to convert
371 * @nmaskbits: size of bitmap, in bits
372 *
373 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
374 * comma-separated sets of eight digits per set.
375 */
376int bitmap_scnprintf(char *buf, unsigned int buflen,
377 const unsigned long *maskp, int nmaskbits)
378{
379 int i, word, bit, len = 0;
380 unsigned long val;
381 const char *sep = "";
382 int chunksz;
383 u32 chunkmask;
384
385 chunksz = nmaskbits & (CHUNKSZ - 1);
386 if (chunksz == 0)
387 chunksz = CHUNKSZ;
388
Nick Wilson8c0e33c2005-06-25 14:59:00 -0700389 i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390 for (; i >= 0; i -= CHUNKSZ) {
391 chunkmask = ((1ULL << chunksz) - 1);
392 word = i / BITS_PER_LONG;
393 bit = i % BITS_PER_LONG;
394 val = (maskp[word] >> bit) & chunkmask;
395 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
396 (chunksz+3)/4, val);
397 chunksz = CHUNKSZ;
398 sep = ",";
399 }
400 return len;
401}
402EXPORT_SYMBOL(bitmap_scnprintf);
403
404/**
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700405 * __bitmap_parse - convert an ASCII hex string into a bitmap.
406 * @buf: pointer to buffer containing string.
407 * @buflen: buffer size in bytes. If string is smaller than this
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 * then it must be terminated with a \0.
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700409 * @is_user: location of buffer, 0 indicates kernel space
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 * @maskp: pointer to bitmap array that will contain result.
411 * @nmaskbits: size of bitmap, in bits.
412 *
413 * Commas group hex digits into chunks. Each chunk defines exactly 32
414 * bits of the resultant bitmask. No chunk may specify a value larger
Randy Dunlap6e1907ff2006-06-25 05:48:57 -0700415 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
416 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 * characters and for grouping errors such as "1,,5", ",44", "," and "".
418 * Leading and trailing whitespace accepted, but not embedded whitespace.
419 */
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700420int __bitmap_parse(const char *buf, unsigned int buflen,
421 int is_user, unsigned long *maskp,
422 int nmaskbits)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423{
424 int c, old_c, totaldigits, ndigits, nchunks, nbits;
425 u32 chunk;
H Hartley Sweetenb9c321f2011-10-31 17:12:32 -0700426 const char __user __force *ubuf = (const char __user __force *)buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427
428 bitmap_zero(maskp, nmaskbits);
429
430 nchunks = nbits = totaldigits = c = 0;
431 do {
432 chunk = ndigits = 0;
433
434 /* Get the next chunk of the bitmap */
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700435 while (buflen) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 old_c = c;
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700437 if (is_user) {
438 if (__get_user(c, ubuf++))
439 return -EFAULT;
440 }
441 else
442 c = *buf++;
443 buflen--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 if (isspace(c))
445 continue;
446
447 /*
448 * If the last character was a space and the current
449 * character isn't '\0', we've got embedded whitespace.
450 * This is a no-no, so throw an error.
451 */
452 if (totaldigits && c && isspace(old_c))
453 return -EINVAL;
454
455 /* A '\0' or a ',' signal the end of the chunk */
456 if (c == '\0' || c == ',')
457 break;
458
459 if (!isxdigit(c))
460 return -EINVAL;
461
462 /*
463 * Make sure there are at least 4 free bits in 'chunk'.
464 * If not, this hexdigit will overflow 'chunk', so
465 * throw an error.
466 */
467 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
468 return -EOVERFLOW;
469
Andy Shevchenko66f19912010-10-26 14:23:03 -0700470 chunk = (chunk << 4) | hex_to_bin(c);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 ndigits++; totaldigits++;
472 }
473 if (ndigits == 0)
474 return -EINVAL;
475 if (nchunks == 0 && chunk == 0)
476 continue;
477
478 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
479 *maskp |= chunk;
480 nchunks++;
481 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
482 if (nbits > nmaskbits)
483 return -EOVERFLOW;
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700484 } while (buflen && c == ',');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485
486 return 0;
487}
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700488EXPORT_SYMBOL(__bitmap_parse);
489
490/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800491 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700492 *
493 * @ubuf: pointer to user buffer containing string.
494 * @ulen: buffer size in bytes. If string is smaller than this
495 * then it must be terminated with a \0.
496 * @maskp: pointer to bitmap array that will contain result.
497 * @nmaskbits: size of bitmap, in bits.
498 *
499 * Wrapper for __bitmap_parse(), providing it with user buffer.
500 *
501 * We cannot have this as an inline function in bitmap.h because it needs
502 * linux/uaccess.h to get the access_ok() declaration and this causes
503 * cyclic dependencies.
504 */
505int bitmap_parse_user(const char __user *ubuf,
506 unsigned int ulen, unsigned long *maskp,
507 int nmaskbits)
508{
509 if (!access_ok(VERIFY_READ, ubuf, ulen))
510 return -EFAULT;
H Hartley Sweetenb9c321f2011-10-31 17:12:32 -0700511 return __bitmap_parse((const char __force *)ubuf,
512 ulen, 1, maskp, nmaskbits);
513
Reinette Chatre01a3ee22006-10-11 01:21:55 -0700514}
515EXPORT_SYMBOL(bitmap_parse_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516
517/*
518 * bscnl_emit(buf, buflen, rbot, rtop, bp)
519 *
520 * Helper routine for bitmap_scnlistprintf(). Write decimal number
521 * or range to buf, suppressing output past buf+buflen, with optional
522 * comma-prefix. Return len of what would be written to buf, if it
523 * all fit.
524 */
525static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
526{
527 if (len > 0)
528 len += scnprintf(buf + len, buflen - len, ",");
529 if (rbot == rtop)
530 len += scnprintf(buf + len, buflen - len, "%d", rbot);
531 else
532 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
533 return len;
534}
535
536/**
537 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
538 * @buf: byte buffer into which string is placed
539 * @buflen: reserved size of @buf, in bytes
540 * @maskp: pointer to bitmap to convert
541 * @nmaskbits: size of bitmap, in bits
542 *
543 * Output format is a comma-separated list of decimal numbers and
544 * ranges. Consecutively set bits are shown as two hyphen-separated
545 * decimal numbers, the smallest and largest bit numbers set in
546 * the range. Output format is compatible with the format
547 * accepted as input by bitmap_parselist().
548 *
549 * The return value is the number of characters which would be
550 * generated for the given input, excluding the trailing '\0', as
551 * per ISO C99.
552 */
553int bitmap_scnlistprintf(char *buf, unsigned int buflen,
554 const unsigned long *maskp, int nmaskbits)
555{
556 int len = 0;
557 /* current bit is 'cur', most recently seen range is [rbot, rtop] */
558 int cur, rbot, rtop;
559
Andi Kleen0b030c22007-11-05 14:50:56 -0800560 if (buflen == 0)
561 return 0;
562 buf[0] = 0;
563
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 rbot = cur = find_first_bit(maskp, nmaskbits);
565 while (cur < nmaskbits) {
566 rtop = cur;
567 cur = find_next_bit(maskp, nmaskbits, cur+1);
568 if (cur >= nmaskbits || cur > rtop + 1) {
569 len = bscnl_emit(buf, buflen, rbot, rtop, len);
570 rbot = cur;
571 }
572 }
573 return len;
574}
575EXPORT_SYMBOL(bitmap_scnlistprintf);
576
577/**
Mike Travis4b060422011-05-24 17:13:12 -0700578 * __bitmap_parselist - convert list format ASCII string to bitmap
Randy Dunlapb0825ee2011-06-15 15:08:10 -0700579 * @buf: read nul-terminated user string from this buffer
Mike Travis4b060422011-05-24 17:13:12 -0700580 * @buflen: buffer size in bytes. If string is smaller than this
581 * then it must be terminated with a \0.
582 * @is_user: location of buffer, 0 indicates kernel space
Randy Dunlap6e1907ff2006-06-25 05:48:57 -0700583 * @maskp: write resulting mask here
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 * @nmaskbits: number of bits in mask to be written
585 *
586 * Input format is a comma-separated list of decimal numbers and
587 * ranges. Consecutively set bits are shown as two hyphen-separated
588 * decimal numbers, the smallest and largest bit numbers set in
589 * the range.
590 *
Randy Dunlap6e1907ff2006-06-25 05:48:57 -0700591 * Returns 0 on success, -errno on invalid input strings.
592 * Error values:
593 * %-EINVAL: second number in range smaller than first
594 * %-EINVAL: invalid character in string
595 * %-ERANGE: bit number specified too large for mask
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 */
Mike Travis4b060422011-05-24 17:13:12 -0700597static int __bitmap_parselist(const char *buf, unsigned int buflen,
598 int is_user, unsigned long *maskp,
599 int nmaskbits)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600{
601 unsigned a, b;
Mike Travis4b060422011-05-24 17:13:12 -0700602 int c, old_c, totaldigits;
H Hartley Sweetenb9c321f2011-10-31 17:12:32 -0700603 const char __user __force *ubuf = (const char __user __force *)buf;
Mike Travis4b060422011-05-24 17:13:12 -0700604 int exp_digit, in_range;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605
Mike Travis4b060422011-05-24 17:13:12 -0700606 totaldigits = c = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 bitmap_zero(maskp, nmaskbits);
608 do {
Mike Travis4b060422011-05-24 17:13:12 -0700609 exp_digit = 1;
610 in_range = 0;
611 a = b = 0;
612
613 /* Get the next cpu# or a range of cpu#'s */
614 while (buflen) {
615 old_c = c;
616 if (is_user) {
617 if (__get_user(c, ubuf++))
618 return -EFAULT;
619 } else
620 c = *buf++;
621 buflen--;
622 if (isspace(c))
623 continue;
624
625 /*
626 * If the last character was a space and the current
627 * character isn't '\0', we've got embedded whitespace.
628 * This is a no-no, so throw an error.
629 */
630 if (totaldigits && c && isspace(old_c))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 return -EINVAL;
Mike Travis4b060422011-05-24 17:13:12 -0700632
633 /* A '\0' or a ',' signal the end of a cpu# or range */
634 if (c == '\0' || c == ',')
635 break;
636
637 if (c == '-') {
638 if (exp_digit || in_range)
639 return -EINVAL;
640 b = 0;
641 in_range = 1;
642 exp_digit = 1;
643 continue;
644 }
645
646 if (!isdigit(c))
647 return -EINVAL;
648
649 b = b * 10 + (c - '0');
650 if (!in_range)
651 a = b;
652 exp_digit = 0;
653 totaldigits++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 }
655 if (!(a <= b))
656 return -EINVAL;
657 if (b >= nmaskbits)
658 return -ERANGE;
659 while (a <= b) {
660 set_bit(a, maskp);
661 a++;
662 }
Mike Travis4b060422011-05-24 17:13:12 -0700663 } while (buflen && c == ',');
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 return 0;
665}
Mike Travis4b060422011-05-24 17:13:12 -0700666
667int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
668{
669 char *nl = strchr(bp, '\n');
670 int len;
671
672 if (nl)
673 len = nl - bp;
674 else
675 len = strlen(bp);
676
677 return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
678}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679EXPORT_SYMBOL(bitmap_parselist);
680
Mike Travis4b060422011-05-24 17:13:12 -0700681
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 */
697int 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;
H Hartley Sweetenb9c321f2011-10-31 17:12:32 -0700703 return __bitmap_parselist((const char __force *)ubuf,
Mike Travis4b060422011-05-24 17:13:12 -0700704 ulen, 1, maskp, nmaskbits);
705}
706EXPORT_SYMBOL(bitmap_parselist_user);
707
708
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800709/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800710 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800711 * @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
Paul Jackson96b7f342006-01-08 01:01:46 -0800717 * is not a valid bit position, map to -1.
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800718 *
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 0. 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 */
727static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
728{
Paul Jackson96b7f342006-01-08 01:01:46 -0800729 int i, ord;
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800730
Paul Jackson96b7f342006-01-08 01:01:46 -0800731 if (pos < 0 || pos >= bits || !test_bit(pos, buf))
732 return -1;
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800733
Paul Jackson96b7f342006-01-08 01:01:46 -0800734 i = find_first_bit(buf, bits);
735 ord = 0;
736 while (i < pos) {
737 i = find_next_bit(buf, bits, i + 1);
738 ord++;
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800739 }
Paul Jackson96b7f342006-01-08 01:01:46 -0800740 BUG_ON(i != pos);
741
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800742 return ord;
743}
744
745/**
Ben Hutchings9a86e2b2010-03-05 13:43:17 -0800746 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800747 * @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.
Paul Jackson96b7f342006-01-08 01:01:46 -0800752 * Value of @ord should be in range 0 <= @ord < weight(buf), else
753 * results are undefined.
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800754 *
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,
Paul Jackson96b7f342006-01-08 01:01:46 -0800757 * and all other @ord values return undefined values. When @ord value 3
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800758 * 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 */
Michal Hocko778d3b02011-07-26 16:08:30 -0700763int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800764{
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
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800783 * @dst: remapped result
Paul Jackson96b7f342006-01-08 01:01:46 -0800784 * @src: subset to be remapped
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800785 * @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 *
Paul Jackson96b7f342006-01-08 01:01:46 -0800796 * 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.
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800799 *
Paul Jackson96b7f342006-01-08 01:01:46 -0800800 * The positions of unset bits in @old are mapped to themselves
801 * (the identify map).
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800802 *
803 * Apply the above specified mapping to @src, placing the result in
804 * @dst, clearing any bits previously set in @dst.
805 *
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800806 * 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
Paul Jackson96b7f342006-01-08 01:01:46 -0800809 * 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.
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800812 */
813void bitmap_remap(unsigned long *dst, const unsigned long *src,
814 const unsigned long *old, const unsigned long *new,
815 int bits)
816{
Paul Jackson96b7f342006-01-08 01:01:46 -0800817 int oldbit, w;
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800818
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800819 if (dst == src) /* following doesn't handle inplace remaps */
820 return;
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800821 bitmap_zero(dst, bits);
Paul Jackson96b7f342006-01-08 01:01:46 -0800822
823 w = bitmap_weight(new, bits);
Akinobu Mita08564fb2010-03-05 13:43:18 -0800824 for_each_set_bit(oldbit, src, bits) {
Paul Jackson96b7f342006-01-08 01:01:46 -0800825 int n = bitmap_pos_to_ord(old, oldbit, bits);
Akinobu Mita08564fb2010-03-05 13:43:18 -0800826
Paul Jackson96b7f342006-01-08 01:01:46 -0800827 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);
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800831 }
832}
833EXPORT_SYMBOL(bitmap_remap);
834
835/**
836 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
Randy Dunlap6e1907ff2006-06-25 05:48:57 -0700837 * @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
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800841 *
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 *
Paul Jackson96b7f342006-01-08 01:01:46 -0800849 * The positions of unset bits in @old are mapped to themselves
850 * (the identify map).
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800851 *
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
Paul Jackson96b7f342006-01-08 01:01:46 -0800858 * bit positions unchanged. So if say @oldbit is 5, then this routine
859 * returns 13.
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800860 */
861int bitmap_bitremap(int oldbit, const unsigned long *old,
862 const unsigned long *new, int bits)
863{
Paul Jackson96b7f342006-01-08 01:01:46 -0800864 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);
Paul Jacksonfb5eeee2005-10-30 15:02:33 -0800870}
871EXPORT_SYMBOL(bitmap_bitremap);
872
Paul Jackson7ea931c2008-04-28 02:12:29 -0700873/**
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
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300922 * @dst corresponding to whatever is the twelfth bit that is
Paul Jackson7ea931c2008-04-28 02:12:29 -0700923 * 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 */
973void 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;
Akinobu Mita08564fb2010-03-05 13:43:18 -0800993 for_each_set_bit(n, relmap, bits) {
Paul Jackson7ea931c2008-04-28 02:12:29 -0700994 /* m == bitmap_pos_to_ord(relmap, n, bits) */
995 if (test_bit(m, orig))
996 set_bit(n, dst);
997 m++;
998 }
999}
1000EXPORT_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 */
1013void 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
Akinobu Mita08564fb2010-03-05 13:43:18 -08001022 for_each_set_bit(oldbit, orig, bits)
Paul Jackson7ea931c2008-04-28 02:12:29 -07001023 set_bit(oldbit % sz, dst);
1024}
1025EXPORT_SYMBOL(bitmap_fold);
1026
Paul Jackson3cf64b92006-03-24 03:15:46 -08001027/*
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
1045enum {
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
1051static int __reg_op(unsigned long *bitmap, 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 }
1099done:
1100 return ret;
1101}
1102
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103/**
Paul Jackson87e24802006-03-24 03:15:44 -08001104 * bitmap_find_free_region - find a contiguous aligned mem region
Paul Jackson3cf64b92006-03-24 03:15:46 -08001105 * @bitmap: array of unsigned longs corresponding to the bitmap
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 * @bits: number of bits in the bitmap
Paul Jackson3cf64b92006-03-24 03:15:46 -08001107 * @order: region size (log base 2 of number of bits) to find
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 *
Paul Jackson3cf64b92006-03-24 03:15:46 -08001109 * 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
Paul Jackson87e24802006-03-24 03:15:44 -08001112 * makes the search algorithm much faster.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 *
Paul Jackson3cf64b92006-03-24 03:15:46 -08001114 * Return the bit offset in bitmap of the allocated region,
Paul Jackson87e24802006-03-24 03:15:44 -08001115 * or -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 */
1117int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
1118{
Linus Torvaldsaa8e4fc2009-03-12 19:32:51 -07001119 int pos, end; /* scans bitmap by regions of size order */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120
Linus Torvaldsaa8e4fc2009-03-12 19:32:51 -07001121 for (pos = 0 ; (end = pos + (1 << 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128}
1129EXPORT_SYMBOL(bitmap_find_free_region);
1130
1131/**
Paul Jackson87e24802006-03-24 03:15:44 -08001132 * bitmap_release_region - release allocated bitmap region
Paul Jackson3cf64b92006-03-24 03:15:46 -08001133 * @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
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08001137 * This is the complement to __bitmap_find_free_region() and releases
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138 * the found region (by clearing it in the bitmap).
Paul Jackson3cf64b92006-03-24 03:15:46 -08001139 *
1140 * No return value.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 */
1142void bitmap_release_region(unsigned long *bitmap, int pos, int order)
1143{
Paul Jackson3cf64b92006-03-24 03:15:46 -08001144 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145}
1146EXPORT_SYMBOL(bitmap_release_region);
1147
Paul Jackson87e24802006-03-24 03:15:44 -08001148/**
1149 * bitmap_allocate_region - allocate bitmap region
Paul Jackson3cf64b92006-03-24 03:15:46 -08001150 * @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
Paul Jackson87e24802006-03-24 03:15:44 -08001153 *
1154 * Allocate (set bits in) a specified region of a bitmap.
Paul Jackson3cf64b92006-03-24 03:15:46 -08001155 *
Randy Dunlap6e1907ff2006-06-25 05:48:57 -07001156 * Return 0 on success, or %-EBUSY if specified region wasn't
Paul Jackson87e24802006-03-24 03:15:44 -08001157 * free (not all bits were zero).
1158 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
1160{
Paul Jackson3cf64b92006-03-24 03:15:46 -08001161 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1162 return -EBUSY;
1163 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 return 0;
1165}
1166EXPORT_SYMBOL(bitmap_allocate_region);
David Vrabelccbe3292008-09-17 16:34:03 +01001167
1168/**
1169 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1170 * @dst: destination buffer
1171 * @src: bitmap to copy
1172 * @nbits: number of bits in the bitmap
1173 *
1174 * Require nbits % BITS_PER_LONG == 0.
1175 */
1176void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1177{
1178 unsigned long *d = dst;
1179 int i;
1180
1181 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1182 if (BITS_PER_LONG == 64)
1183 d[i] = cpu_to_le64(src[i]);
1184 else
1185 d[i] = cpu_to_le32(src[i]);
1186 }
1187}
1188EXPORT_SYMBOL(bitmap_copy_le);