projects/linux·blob v2.6.13-rc1 · refs

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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/module.h>
9#include <linux/ctype.h>
10#include <linux/errno.h>
11#include <linux/bitmap.h>
12#include <linux/bitops.h>
13#include <asm/uaccess.h>
14
15/*
16 * bitmaps provide an array of bits, implemented using an an
17 * array of unsigned longs. The number of valid bits in a
18 * given bitmap does _not_ need to be an exact multiple of
19 * BITS_PER_LONG.
20 *
21 * The possible unused bits in the last, partially used word
22 * of a bitmap are 'don't care'. The implementation makes
23 * no particular effort to keep them zero. It ensures that
24 * their value will not affect the results of any operation.
25 * The bitmap operations that return Boolean (bitmap_empty,
26 * for example) or scalar (bitmap_weight, for example) results
27 * carefully filter out these unused bits from impacting their
28 * results.
29 *
30 * These operations actually hold to a slightly stronger rule:
31 * if you don't input any bitmaps to these ops that have some
32 * unused bits set, then they won't output any set unused bits
33 * in output bitmaps.
34 *
35 * The byte ordering of bitmaps is more natural on little
36 * endian architectures. See the big-endian headers
37 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
38 * for the best explanations of this ordering.
39 */
40
41int __bitmap_empty(const unsigned long *bitmap, int bits)
42{
43 int k, lim = bits/BITS_PER_LONG;
44 for (k = 0; k < lim; ++k)
45 if (bitmap[k])
46 return 0;
47
48 if (bits % BITS_PER_LONG)
49 if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
50 return 0;
51
52 return 1;
53}
54EXPORT_SYMBOL(__bitmap_empty);
55
56int __bitmap_full(const unsigned long *bitmap, int bits)
57{
58 int k, lim = bits/BITS_PER_LONG;
59 for (k = 0; k < lim; ++k)
60 if (~bitmap[k])
61 return 0;
62
63 if (bits % BITS_PER_LONG)
64 if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
65 return 0;
66
67 return 1;
68}
69EXPORT_SYMBOL(__bitmap_full);
70
71int __bitmap_equal(const unsigned long *bitmap1,
72 const unsigned long *bitmap2, int bits)
73{
74 int k, lim = bits/BITS_PER_LONG;
75 for (k = 0; k < lim; ++k)
76 if (bitmap1[k] != bitmap2[k])
77 return 0;
78
79 if (bits % BITS_PER_LONG)
80 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
81 return 0;
82
83 return 1;
84}
85EXPORT_SYMBOL(__bitmap_equal);
86
87void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
88{
89 int k, lim = bits/BITS_PER_LONG;
90 for (k = 0; k < lim; ++k)
91 dst[k] = ~src[k];
92
93 if (bits % BITS_PER_LONG)
94 dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
95}
96EXPORT_SYMBOL(__bitmap_complement);
97
98/*
99 * __bitmap_shift_right - logical right shift of the bits in a bitmap
100 * @dst - destination bitmap
101 * @src - source bitmap
102 * @nbits - shift by this many bits
103 * @bits - bitmap size, in bits
104 *
105 * Shifting right (dividing) means moving bits in the MS -> LS bit
106 * direction. Zeros are fed into the vacated MS positions and the
107 * LS bits shifted off the bottom are lost.
108 */
109void __bitmap_shift_right(unsigned long *dst,
110 const unsigned long *src, int shift, int bits)
111{
112 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
113 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
114 unsigned long mask = (1UL << left) - 1;
115 for (k = 0; off + k < lim; ++k) {
116 unsigned long upper, lower;
117
118 /*
119 * If shift is not word aligned, take lower rem bits of
120 * word above and make them the top rem bits of result.
121 */
122 if (!rem || off + k + 1 >= lim)
123 upper = 0;
124 else {
125 upper = src[off + k + 1];
126 if (off + k + 1 == lim - 1 && left)
127 upper &= mask;
128 }
129 lower = src[off + k];
130 if (left && off + k == lim - 1)
131 lower &= mask;
132 dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
133 if (left && k == lim - 1)
134 dst[k] &= mask;
135 }
136 if (off)
137 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
138}
139EXPORT_SYMBOL(__bitmap_shift_right);
140
141
142/*
143 * __bitmap_shift_left - logical left shift of the bits in a bitmap
144 * @dst - destination bitmap
145 * @src - source bitmap
146 * @nbits - shift by this many bits
147 * @bits - bitmap size, in bits
148 *
149 * Shifting left (multiplying) means moving bits in the LS -> MS
150 * direction. Zeros are fed into the vacated LS bit positions
151 * and those MS bits shifted off the top are lost.
152 */
153
154void __bitmap_shift_left(unsigned long *dst,
155 const unsigned long *src, int shift, int bits)
156{
157 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
158 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
159 for (k = lim - off - 1; k >= 0; --k) {
160 unsigned long upper, lower;
161
162 /*
163 * If shift is not word aligned, take upper rem bits of
164 * word below and make them the bottom rem bits of result.
165 */
166 if (rem && k > 0)
167 lower = src[k - 1];
168 else
169 lower = 0;
170 upper = src[k];
171 if (left && k == lim - 1)
172 upper &= (1UL << left) - 1;
173 dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
174 if (left && k + off == lim - 1)
175 dst[k + off] &= (1UL << left) - 1;
176 }
177 if (off)
178 memset(dst, 0, off*sizeof(unsigned long));
179}
180EXPORT_SYMBOL(__bitmap_shift_left);
181
182void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
183 const unsigned long *bitmap2, int bits)
184{
185 int k;
186 int nr = BITS_TO_LONGS(bits);
187
188 for (k = 0; k < nr; k++)
189 dst[k] = bitmap1[k] & bitmap2[k];
190}
191EXPORT_SYMBOL(__bitmap_and);
192
193void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
194 const unsigned long *bitmap2, int bits)
195{
196 int k;
197 int nr = BITS_TO_LONGS(bits);
198
199 for (k = 0; k < nr; k++)
200 dst[k] = bitmap1[k] | bitmap2[k];
201}
202EXPORT_SYMBOL(__bitmap_or);
203
204void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
205 const unsigned long *bitmap2, int bits)
206{
207 int k;
208 int nr = BITS_TO_LONGS(bits);
209
210 for (k = 0; k < nr; k++)
211 dst[k] = bitmap1[k] ^ bitmap2[k];
212}
213EXPORT_SYMBOL(__bitmap_xor);
214
215void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
216 const unsigned long *bitmap2, int bits)
217{
218 int k;
219 int nr = BITS_TO_LONGS(bits);
220
221 for (k = 0; k < nr; k++)
222 dst[k] = bitmap1[k] & ~bitmap2[k];
223}
224EXPORT_SYMBOL(__bitmap_andnot);
225
226int __bitmap_intersects(const unsigned long *bitmap1,
227 const unsigned long *bitmap2, int bits)
228{
229 int k, lim = bits/BITS_PER_LONG;
230 for (k = 0; k < lim; ++k)
231 if (bitmap1[k] & bitmap2[k])
232 return 1;
233
234 if (bits % BITS_PER_LONG)
235 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
236 return 1;
237 return 0;
238}
239EXPORT_SYMBOL(__bitmap_intersects);
240
241int __bitmap_subset(const unsigned long *bitmap1,
242 const unsigned long *bitmap2, int bits)
243{
244 int k, lim = bits/BITS_PER_LONG;
245 for (k = 0; k < lim; ++k)
246 if (bitmap1[k] & ~bitmap2[k])
247 return 0;
248
249 if (bits % BITS_PER_LONG)
250 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
251 return 0;
252 return 1;
253}
254EXPORT_SYMBOL(__bitmap_subset);
255
256#if BITS_PER_LONG == 32
257int __bitmap_weight(const unsigned long *bitmap, int bits)
258{
259 int k, w = 0, lim = bits/BITS_PER_LONG;
260
261 for (k = 0; k < lim; k++)
262 w += hweight32(bitmap[k]);
263
264 if (bits % BITS_PER_LONG)
265 w += hweight32(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
266
267 return w;
268}
269#else
270int __bitmap_weight(const unsigned long *bitmap, int bits)
271{
272 int k, w = 0, lim = bits/BITS_PER_LONG;
273
274 for (k = 0; k < lim; k++)
275 w += hweight64(bitmap[k]);
276
277 if (bits % BITS_PER_LONG)
278 w += hweight64(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
279
280 return w;
281}
282#endif
283EXPORT_SYMBOL(__bitmap_weight);
284
285/*
286 * Bitmap printing & parsing functions: first version by Bill Irwin,
287 * second version by Paul Jackson, third by Joe Korty.
288 */
289
290#define CHUNKSZ 32
291#define nbits_to_hold_value(val) fls(val)
292#define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))
293#define BASEDEC 10 /* fancier cpuset lists input in decimal */
294
295/**
296 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
297 * @buf: byte buffer into which string is placed
298 * @buflen: reserved size of @buf, in bytes
299 * @maskp: pointer to bitmap to convert
300 * @nmaskbits: size of bitmap, in bits
301 *
302 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
303 * comma-separated sets of eight digits per set.
304 */
305int bitmap_scnprintf(char *buf, unsigned int buflen,
306 const unsigned long *maskp, int nmaskbits)
307{
308 int i, word, bit, len = 0;
309 unsigned long val;
310 const char *sep = "";
311 int chunksz;
312 u32 chunkmask;
313
314 chunksz = nmaskbits & (CHUNKSZ - 1);
315 if (chunksz == 0)
316 chunksz = CHUNKSZ;
317
318 i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
319 for (; i >= 0; i -= CHUNKSZ) {
320 chunkmask = ((1ULL << chunksz) - 1);
321 word = i / BITS_PER_LONG;
322 bit = i % BITS_PER_LONG;
323 val = (maskp[word] >> bit) & chunkmask;
324 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
325 (chunksz+3)/4, val);
326 chunksz = CHUNKSZ;
327 sep = ",";
328 }
329 return len;
330}
331EXPORT_SYMBOL(bitmap_scnprintf);
332
333/**
334 * bitmap_parse - convert an ASCII hex string into a bitmap.
335 * @buf: pointer to buffer in user space containing string.
336 * @buflen: buffer size in bytes. If string is smaller than this
337 * then it must be terminated with a \0.
338 * @maskp: pointer to bitmap array that will contain result.
339 * @nmaskbits: size of bitmap, in bits.
340 *
341 * Commas group hex digits into chunks. Each chunk defines exactly 32
342 * bits of the resultant bitmask. No chunk may specify a value larger
343 * than 32 bits (-EOVERFLOW), and if a chunk specifies a smaller value
344 * then leading 0-bits are prepended. -EINVAL is returned for illegal
345 * characters and for grouping errors such as "1,,5", ",44", "," and "".
346 * Leading and trailing whitespace accepted, but not embedded whitespace.
347 */
348int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
349 unsigned long *maskp, int nmaskbits)
350{
351 int c, old_c, totaldigits, ndigits, nchunks, nbits;
352 u32 chunk;
353
354 bitmap_zero(maskp, nmaskbits);
355
356 nchunks = nbits = totaldigits = c = 0;
357 do {
358 chunk = ndigits = 0;
359
360 /* Get the next chunk of the bitmap */
361 while (ubuflen) {
362 old_c = c;
363 if (get_user(c, ubuf++))
364 return -EFAULT;
365 ubuflen--;
366 if (isspace(c))
367 continue;
368
369 /*
370 * If the last character was a space and the current
371 * character isn't '\0', we've got embedded whitespace.
372 * This is a no-no, so throw an error.
373 */
374 if (totaldigits && c && isspace(old_c))
375 return -EINVAL;
376
377 /* A '\0' or a ',' signal the end of the chunk */
378 if (c == '\0' || c == ',')
379 break;
380
381 if (!isxdigit(c))
382 return -EINVAL;
383
384 /*
385 * Make sure there are at least 4 free bits in 'chunk'.
386 * If not, this hexdigit will overflow 'chunk', so
387 * throw an error.
388 */
389 if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
390 return -EOVERFLOW;
391
392 chunk = (chunk << 4) | unhex(c);
393 ndigits++; totaldigits++;
394 }
395 if (ndigits == 0)
396 return -EINVAL;
397 if (nchunks == 0 && chunk == 0)
398 continue;
399
400 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
401 *maskp |= chunk;
402 nchunks++;
403 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
404 if (nbits > nmaskbits)
405 return -EOVERFLOW;
406 } while (ubuflen && c == ',');
407
408 return 0;
409}
410EXPORT_SYMBOL(bitmap_parse);
411
412/*
413 * bscnl_emit(buf, buflen, rbot, rtop, bp)
414 *
415 * Helper routine for bitmap_scnlistprintf(). Write decimal number
416 * or range to buf, suppressing output past buf+buflen, with optional
417 * comma-prefix. Return len of what would be written to buf, if it
418 * all fit.
419 */
420static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
421{
422 if (len > 0)
423 len += scnprintf(buf + len, buflen - len, ",");
424 if (rbot == rtop)
425 len += scnprintf(buf + len, buflen - len, "%d", rbot);
426 else
427 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
428 return len;
429}
430
431/**
432 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
433 * @buf: byte buffer into which string is placed
434 * @buflen: reserved size of @buf, in bytes
435 * @maskp: pointer to bitmap to convert
436 * @nmaskbits: size of bitmap, in bits
437 *
438 * Output format is a comma-separated list of decimal numbers and
439 * ranges. Consecutively set bits are shown as two hyphen-separated
440 * decimal numbers, the smallest and largest bit numbers set in
441 * the range. Output format is compatible with the format
442 * accepted as input by bitmap_parselist().
443 *
444 * The return value is the number of characters which would be
445 * generated for the given input, excluding the trailing '\0', as
446 * per ISO C99.
447 */
448int bitmap_scnlistprintf(char *buf, unsigned int buflen,
449 const unsigned long *maskp, int nmaskbits)
450{
451 int len = 0;
452 /* current bit is 'cur', most recently seen range is [rbot, rtop] */
453 int cur, rbot, rtop;
454
455 rbot = cur = find_first_bit(maskp, nmaskbits);
456 while (cur < nmaskbits) {
457 rtop = cur;
458 cur = find_next_bit(maskp, nmaskbits, cur+1);
459 if (cur >= nmaskbits || cur > rtop + 1) {
460 len = bscnl_emit(buf, buflen, rbot, rtop, len);
461 rbot = cur;
462 }
463 }
464 return len;
465}
466EXPORT_SYMBOL(bitmap_scnlistprintf);
467
468/**
469 * bitmap_parselist - convert list format ASCII string to bitmap
470 * @buf: read nul-terminated user string from this buffer
471 * @mask: write resulting mask here
472 * @nmaskbits: number of bits in mask to be written
473 *
474 * Input format is a comma-separated list of decimal numbers and
475 * ranges. Consecutively set bits are shown as two hyphen-separated
476 * decimal numbers, the smallest and largest bit numbers set in
477 * the range.
478 *
479 * Returns 0 on success, -errno on invalid input strings:
480 * -EINVAL: second number in range smaller than first
481 * -EINVAL: invalid character in string
482 * -ERANGE: bit number specified too large for mask
483 */
484int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
485{
486 unsigned a, b;
487
488 bitmap_zero(maskp, nmaskbits);
489 do {
490 if (!isdigit(*bp))
491 return -EINVAL;
492 b = a = simple_strtoul(bp, (char **)&bp, BASEDEC);
493 if (*bp == '-') {
494 bp++;
495 if (!isdigit(*bp))
496 return -EINVAL;
497 b = simple_strtoul(bp, (char **)&bp, BASEDEC);
498 }
499 if (!(a <= b))
500 return -EINVAL;
501 if (b >= nmaskbits)
502 return -ERANGE;
503 while (a <= b) {
504 set_bit(a, maskp);
505 a++;
506 }
507 if (*bp == ',')
508 bp++;
509 } while (*bp != '\0' && *bp != '\n');
510 return 0;
511}
512EXPORT_SYMBOL(bitmap_parselist);
513
514/**
515 * bitmap_find_free_region - find a contiguous aligned mem region
516 * @bitmap: an array of unsigned longs corresponding to the bitmap
517 * @bits: number of bits in the bitmap
518 * @order: region size to find (size is actually 1<<order)
519 *
520 * This is used to allocate a memory region from a bitmap. The idea is
521 * that the region has to be 1<<order sized and 1<<order aligned (this
522 * makes the search algorithm much faster).
523 *
524 * The region is marked as set bits in the bitmap if a free one is
525 * found.
526 *
527 * Returns either beginning of region or negative error
528 */
529int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
530{
531 unsigned long mask;
532 int pages = 1 << order;
533 int i;
534
535 if(pages > BITS_PER_LONG)
536 return -EINVAL;
537
538 /* make a mask of the order */
539 mask = (1ul << (pages - 1));
540 mask += mask - 1;
541
542 /* run up the bitmap pages bits at a time */
543 for (i = 0; i < bits; i += pages) {
544 int index = i/BITS_PER_LONG;
545 int offset = i - (index * BITS_PER_LONG);
546 if((bitmap[index] & (mask << offset)) == 0) {
547 /* set region in bimap */
548 bitmap[index] |= (mask << offset);
549 return i;
550 }
551 }
552 return -ENOMEM;
553}
554EXPORT_SYMBOL(bitmap_find_free_region);
555
556/**
557 * bitmap_release_region - release allocated bitmap region
558 * @bitmap: a pointer to the bitmap
559 * @pos: the beginning of the region
560 * @order: the order of the bits to release (number is 1<<order)
561 *
562 * This is the complement to __bitmap_find_free_region and releases
563 * the found region (by clearing it in the bitmap).
564 */
565void bitmap_release_region(unsigned long *bitmap, int pos, int order)
566{
567 int pages = 1 << order;
568 unsigned long mask = (1ul << (pages - 1));
569 int index = pos/BITS_PER_LONG;
570 int offset = pos - (index * BITS_PER_LONG);
571 mask += mask - 1;
572 bitmap[index] &= ~(mask << offset);
573}
574EXPORT_SYMBOL(bitmap_release_region);
575
576int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
577{
578 int pages = 1 << order;
579 unsigned long mask = (1ul << (pages - 1));
580 int index = pos/BITS_PER_LONG;
581 int offset = pos - (index * BITS_PER_LONG);
582
583 /* We don't do regions of pages > BITS_PER_LONG. The
584 * algorithm would be a simple look for multiple zeros in the
585 * array, but there's no driver today that needs this. If you
586 * trip this BUG(), you get to code it... */
587 BUG_ON(pages > BITS_PER_LONG);
588 mask += mask - 1;
589 if (bitmap[index] & (mask << offset))
590 return -EBUSY;
591 bitmap[index] |= (mask << offset);
592 return 0;
593}
594EXPORT_SYMBOL(bitmap_allocate_region);