Commit | Line | Data |
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1da177e4 LT |
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 | ||
41 | int __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 | } | |
54 | EXPORT_SYMBOL(__bitmap_empty); | |
55 | ||
56 | int __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 | } | |
69 | EXPORT_SYMBOL(__bitmap_full); | |
70 | ||
71 | int __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 | } | |
85 | EXPORT_SYMBOL(__bitmap_equal); | |
86 | ||
87 | void __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 | } | |
96 | EXPORT_SYMBOL(__bitmap_complement); | |
97 | ||
72fd4a35 | 98 | /** |
1da177e4 | 99 | * __bitmap_shift_right - logical right shift of the bits in a bitmap |
05fb6bf0 RD |
100 | * @dst : destination bitmap |
101 | * @src : source bitmap | |
102 | * @shift : shift by this many bits | |
103 | * @bits : bitmap size, in bits | |
1da177e4 LT |
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 | */ | |
109 | void __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 | } | |
139 | EXPORT_SYMBOL(__bitmap_shift_right); | |
140 | ||
141 | ||
72fd4a35 | 142 | /** |
1da177e4 | 143 | * __bitmap_shift_left - logical left shift of the bits in a bitmap |
05fb6bf0 RD |
144 | * @dst : destination bitmap |
145 | * @src : source bitmap | |
146 | * @shift : shift by this many bits | |
147 | * @bits : bitmap size, in bits | |
1da177e4 LT |
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 | ||
154 | void __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 | } | |
180 | EXPORT_SYMBOL(__bitmap_shift_left); | |
181 | ||
182 | void __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 | } | |
191 | EXPORT_SYMBOL(__bitmap_and); | |
192 | ||
193 | void __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 | } | |
202 | EXPORT_SYMBOL(__bitmap_or); | |
203 | ||
204 | void __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 | } | |
213 | EXPORT_SYMBOL(__bitmap_xor); | |
214 | ||
215 | void __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 | } | |
224 | EXPORT_SYMBOL(__bitmap_andnot); | |
225 | ||
226 | int __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 | } | |
239 | EXPORT_SYMBOL(__bitmap_intersects); | |
240 | ||
241 | int __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 | } | |
254 | EXPORT_SYMBOL(__bitmap_subset); | |
255 | ||
1da177e4 LT |
256 | int __bitmap_weight(const unsigned long *bitmap, int bits) |
257 | { | |
258 | int k, w = 0, lim = bits/BITS_PER_LONG; | |
259 | ||
260 | for (k = 0; k < lim; k++) | |
37d54111 | 261 | w += hweight_long(bitmap[k]); |
1da177e4 LT |
262 | |
263 | if (bits % BITS_PER_LONG) | |
37d54111 | 264 | w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); |
1da177e4 LT |
265 | |
266 | return w; | |
267 | } | |
1da177e4 LT |
268 | EXPORT_SYMBOL(__bitmap_weight); |
269 | ||
270 | /* | |
271 | * Bitmap printing & parsing functions: first version by Bill Irwin, | |
272 | * second version by Paul Jackson, third by Joe Korty. | |
273 | */ | |
274 | ||
275 | #define CHUNKSZ 32 | |
276 | #define nbits_to_hold_value(val) fls(val) | |
1da177e4 LT |
277 | #define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10)) |
278 | #define BASEDEC 10 /* fancier cpuset lists input in decimal */ | |
279 | ||
280 | /** | |
281 | * bitmap_scnprintf - convert bitmap to an ASCII hex string. | |
282 | * @buf: byte buffer into which string is placed | |
283 | * @buflen: reserved size of @buf, in bytes | |
284 | * @maskp: pointer to bitmap to convert | |
285 | * @nmaskbits: size of bitmap, in bits | |
286 | * | |
287 | * Exactly @nmaskbits bits are displayed. Hex digits are grouped into | |
288 | * comma-separated sets of eight digits per set. | |
289 | */ | |
290 | int bitmap_scnprintf(char *buf, unsigned int buflen, | |
291 | const unsigned long *maskp, int nmaskbits) | |
292 | { | |
293 | int i, word, bit, len = 0; | |
294 | unsigned long val; | |
295 | const char *sep = ""; | |
296 | int chunksz; | |
297 | u32 chunkmask; | |
298 | ||
299 | chunksz = nmaskbits & (CHUNKSZ - 1); | |
300 | if (chunksz == 0) | |
301 | chunksz = CHUNKSZ; | |
302 | ||
8c0e33c1 | 303 | i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ; |
1da177e4 LT |
304 | for (; i >= 0; i -= CHUNKSZ) { |
305 | chunkmask = ((1ULL << chunksz) - 1); | |
306 | word = i / BITS_PER_LONG; | |
307 | bit = i % BITS_PER_LONG; | |
308 | val = (maskp[word] >> bit) & chunkmask; | |
309 | len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep, | |
310 | (chunksz+3)/4, val); | |
311 | chunksz = CHUNKSZ; | |
312 | sep = ","; | |
313 | } | |
314 | return len; | |
315 | } | |
316 | EXPORT_SYMBOL(bitmap_scnprintf); | |
317 | ||
318 | /** | |
01a3ee2b RC |
319 | * __bitmap_parse - convert an ASCII hex string into a bitmap. |
320 | * @buf: pointer to buffer containing string. | |
321 | * @buflen: buffer size in bytes. If string is smaller than this | |
1da177e4 | 322 | * then it must be terminated with a \0. |
01a3ee2b | 323 | * @is_user: location of buffer, 0 indicates kernel space |
1da177e4 LT |
324 | * @maskp: pointer to bitmap array that will contain result. |
325 | * @nmaskbits: size of bitmap, in bits. | |
326 | * | |
327 | * Commas group hex digits into chunks. Each chunk defines exactly 32 | |
328 | * bits of the resultant bitmask. No chunk may specify a value larger | |
6e1907ff RD |
329 | * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value |
330 | * then leading 0-bits are prepended. %-EINVAL is returned for illegal | |
1da177e4 LT |
331 | * characters and for grouping errors such as "1,,5", ",44", "," and "". |
332 | * Leading and trailing whitespace accepted, but not embedded whitespace. | |
333 | */ | |
01a3ee2b RC |
334 | int __bitmap_parse(const char *buf, unsigned int buflen, |
335 | int is_user, unsigned long *maskp, | |
336 | int nmaskbits) | |
1da177e4 LT |
337 | { |
338 | int c, old_c, totaldigits, ndigits, nchunks, nbits; | |
339 | u32 chunk; | |
01a3ee2b | 340 | const char __user *ubuf = buf; |
1da177e4 LT |
341 | |
342 | bitmap_zero(maskp, nmaskbits); | |
343 | ||
344 | nchunks = nbits = totaldigits = c = 0; | |
345 | do { | |
346 | chunk = ndigits = 0; | |
347 | ||
348 | /* Get the next chunk of the bitmap */ | |
01a3ee2b | 349 | while (buflen) { |
1da177e4 | 350 | old_c = c; |
01a3ee2b RC |
351 | if (is_user) { |
352 | if (__get_user(c, ubuf++)) | |
353 | return -EFAULT; | |
354 | } | |
355 | else | |
356 | c = *buf++; | |
357 | buflen--; | |
1da177e4 LT |
358 | if (isspace(c)) |
359 | continue; | |
360 | ||
361 | /* | |
362 | * If the last character was a space and the current | |
363 | * character isn't '\0', we've got embedded whitespace. | |
364 | * This is a no-no, so throw an error. | |
365 | */ | |
366 | if (totaldigits && c && isspace(old_c)) | |
367 | return -EINVAL; | |
368 | ||
369 | /* A '\0' or a ',' signal the end of the chunk */ | |
370 | if (c == '\0' || c == ',') | |
371 | break; | |
372 | ||
373 | if (!isxdigit(c)) | |
374 | return -EINVAL; | |
375 | ||
376 | /* | |
377 | * Make sure there are at least 4 free bits in 'chunk'. | |
378 | * If not, this hexdigit will overflow 'chunk', so | |
379 | * throw an error. | |
380 | */ | |
381 | if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) | |
382 | return -EOVERFLOW; | |
383 | ||
384 | chunk = (chunk << 4) | unhex(c); | |
385 | ndigits++; totaldigits++; | |
386 | } | |
387 | if (ndigits == 0) | |
388 | return -EINVAL; | |
389 | if (nchunks == 0 && chunk == 0) | |
390 | continue; | |
391 | ||
392 | __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); | |
393 | *maskp |= chunk; | |
394 | nchunks++; | |
395 | nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; | |
396 | if (nbits > nmaskbits) | |
397 | return -EOVERFLOW; | |
01a3ee2b | 398 | } while (buflen && c == ','); |
1da177e4 LT |
399 | |
400 | return 0; | |
401 | } | |
01a3ee2b RC |
402 | EXPORT_SYMBOL(__bitmap_parse); |
403 | ||
404 | /** | |
405 | * bitmap_parse_user() | |
406 | * | |
407 | * @ubuf: pointer to user buffer containing string. | |
408 | * @ulen: buffer size in bytes. If string is smaller than this | |
409 | * then it must be terminated with a \0. | |
410 | * @maskp: pointer to bitmap array that will contain result. | |
411 | * @nmaskbits: size of bitmap, in bits. | |
412 | * | |
413 | * Wrapper for __bitmap_parse(), providing it with user buffer. | |
414 | * | |
415 | * We cannot have this as an inline function in bitmap.h because it needs | |
416 | * linux/uaccess.h to get the access_ok() declaration and this causes | |
417 | * cyclic dependencies. | |
418 | */ | |
419 | int bitmap_parse_user(const char __user *ubuf, | |
420 | unsigned int ulen, unsigned long *maskp, | |
421 | int nmaskbits) | |
422 | { | |
423 | if (!access_ok(VERIFY_READ, ubuf, ulen)) | |
424 | return -EFAULT; | |
425 | return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits); | |
426 | } | |
427 | EXPORT_SYMBOL(bitmap_parse_user); | |
1da177e4 LT |
428 | |
429 | /* | |
430 | * bscnl_emit(buf, buflen, rbot, rtop, bp) | |
431 | * | |
432 | * Helper routine for bitmap_scnlistprintf(). Write decimal number | |
433 | * or range to buf, suppressing output past buf+buflen, with optional | |
434 | * comma-prefix. Return len of what would be written to buf, if it | |
435 | * all fit. | |
436 | */ | |
437 | static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len) | |
438 | { | |
439 | if (len > 0) | |
440 | len += scnprintf(buf + len, buflen - len, ","); | |
441 | if (rbot == rtop) | |
442 | len += scnprintf(buf + len, buflen - len, "%d", rbot); | |
443 | else | |
444 | len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop); | |
445 | return len; | |
446 | } | |
447 | ||
448 | /** | |
449 | * bitmap_scnlistprintf - convert bitmap to list format ASCII string | |
450 | * @buf: byte buffer into which string is placed | |
451 | * @buflen: reserved size of @buf, in bytes | |
452 | * @maskp: pointer to bitmap to convert | |
453 | * @nmaskbits: size of bitmap, in bits | |
454 | * | |
455 | * Output format is a comma-separated list of decimal numbers and | |
456 | * ranges. Consecutively set bits are shown as two hyphen-separated | |
457 | * decimal numbers, the smallest and largest bit numbers set in | |
458 | * the range. Output format is compatible with the format | |
459 | * accepted as input by bitmap_parselist(). | |
460 | * | |
461 | * The return value is the number of characters which would be | |
462 | * generated for the given input, excluding the trailing '\0', as | |
463 | * per ISO C99. | |
464 | */ | |
465 | int bitmap_scnlistprintf(char *buf, unsigned int buflen, | |
466 | const unsigned long *maskp, int nmaskbits) | |
467 | { | |
468 | int len = 0; | |
469 | /* current bit is 'cur', most recently seen range is [rbot, rtop] */ | |
470 | int cur, rbot, rtop; | |
471 | ||
472 | rbot = cur = find_first_bit(maskp, nmaskbits); | |
473 | while (cur < nmaskbits) { | |
474 | rtop = cur; | |
475 | cur = find_next_bit(maskp, nmaskbits, cur+1); | |
476 | if (cur >= nmaskbits || cur > rtop + 1) { | |
477 | len = bscnl_emit(buf, buflen, rbot, rtop, len); | |
478 | rbot = cur; | |
479 | } | |
480 | } | |
481 | return len; | |
482 | } | |
483 | EXPORT_SYMBOL(bitmap_scnlistprintf); | |
484 | ||
485 | /** | |
486 | * bitmap_parselist - convert list format ASCII string to bitmap | |
6e1907ff RD |
487 | * @bp: read nul-terminated user string from this buffer |
488 | * @maskp: write resulting mask here | |
1da177e4 LT |
489 | * @nmaskbits: number of bits in mask to be written |
490 | * | |
491 | * Input format is a comma-separated list of decimal numbers and | |
492 | * ranges. Consecutively set bits are shown as two hyphen-separated | |
493 | * decimal numbers, the smallest and largest bit numbers set in | |
494 | * the range. | |
495 | * | |
6e1907ff RD |
496 | * Returns 0 on success, -errno on invalid input strings. |
497 | * Error values: | |
498 | * %-EINVAL: second number in range smaller than first | |
499 | * %-EINVAL: invalid character in string | |
500 | * %-ERANGE: bit number specified too large for mask | |
1da177e4 LT |
501 | */ |
502 | int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) | |
503 | { | |
504 | unsigned a, b; | |
505 | ||
506 | bitmap_zero(maskp, nmaskbits); | |
507 | do { | |
508 | if (!isdigit(*bp)) | |
509 | return -EINVAL; | |
510 | b = a = simple_strtoul(bp, (char **)&bp, BASEDEC); | |
511 | if (*bp == '-') { | |
512 | bp++; | |
513 | if (!isdigit(*bp)) | |
514 | return -EINVAL; | |
515 | b = simple_strtoul(bp, (char **)&bp, BASEDEC); | |
516 | } | |
517 | if (!(a <= b)) | |
518 | return -EINVAL; | |
519 | if (b >= nmaskbits) | |
520 | return -ERANGE; | |
521 | while (a <= b) { | |
522 | set_bit(a, maskp); | |
523 | a++; | |
524 | } | |
525 | if (*bp == ',') | |
526 | bp++; | |
527 | } while (*bp != '\0' && *bp != '\n'); | |
528 | return 0; | |
529 | } | |
530 | EXPORT_SYMBOL(bitmap_parselist); | |
531 | ||
72fd4a35 | 532 | /** |
fb5eeeee PJ |
533 | * bitmap_pos_to_ord(buf, pos, bits) |
534 | * @buf: pointer to a bitmap | |
535 | * @pos: a bit position in @buf (0 <= @pos < @bits) | |
536 | * @bits: number of valid bit positions in @buf | |
537 | * | |
538 | * Map the bit at position @pos in @buf (of length @bits) to the | |
539 | * ordinal of which set bit it is. If it is not set or if @pos | |
96b7f341 | 540 | * is not a valid bit position, map to -1. |
fb5eeeee PJ |
541 | * |
542 | * If for example, just bits 4 through 7 are set in @buf, then @pos | |
543 | * values 4 through 7 will get mapped to 0 through 3, respectively, | |
544 | * and other @pos values will get mapped to 0. When @pos value 7 | |
545 | * gets mapped to (returns) @ord value 3 in this example, that means | |
546 | * that bit 7 is the 3rd (starting with 0th) set bit in @buf. | |
547 | * | |
548 | * The bit positions 0 through @bits are valid positions in @buf. | |
549 | */ | |
550 | static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits) | |
551 | { | |
96b7f341 | 552 | int i, ord; |
fb5eeeee | 553 | |
96b7f341 PJ |
554 | if (pos < 0 || pos >= bits || !test_bit(pos, buf)) |
555 | return -1; | |
fb5eeeee | 556 | |
96b7f341 PJ |
557 | i = find_first_bit(buf, bits); |
558 | ord = 0; | |
559 | while (i < pos) { | |
560 | i = find_next_bit(buf, bits, i + 1); | |
561 | ord++; | |
fb5eeeee | 562 | } |
96b7f341 PJ |
563 | BUG_ON(i != pos); |
564 | ||
fb5eeeee PJ |
565 | return ord; |
566 | } | |
567 | ||
568 | /** | |
569 | * bitmap_ord_to_pos(buf, ord, bits) | |
570 | * @buf: pointer to bitmap | |
571 | * @ord: ordinal bit position (n-th set bit, n >= 0) | |
572 | * @bits: number of valid bit positions in @buf | |
573 | * | |
574 | * Map the ordinal offset of bit @ord in @buf to its position in @buf. | |
96b7f341 PJ |
575 | * Value of @ord should be in range 0 <= @ord < weight(buf), else |
576 | * results are undefined. | |
fb5eeeee PJ |
577 | * |
578 | * If for example, just bits 4 through 7 are set in @buf, then @ord | |
579 | * values 0 through 3 will get mapped to 4 through 7, respectively, | |
96b7f341 | 580 | * and all other @ord values return undefined values. When @ord value 3 |
fb5eeeee PJ |
581 | * gets mapped to (returns) @pos value 7 in this example, that means |
582 | * that the 3rd set bit (starting with 0th) is at position 7 in @buf. | |
583 | * | |
584 | * The bit positions 0 through @bits are valid positions in @buf. | |
585 | */ | |
586 | static int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) | |
587 | { | |
588 | int pos = 0; | |
589 | ||
590 | if (ord >= 0 && ord < bits) { | |
591 | int i; | |
592 | ||
593 | for (i = find_first_bit(buf, bits); | |
594 | i < bits && ord > 0; | |
595 | i = find_next_bit(buf, bits, i + 1)) | |
596 | ord--; | |
597 | if (i < bits && ord == 0) | |
598 | pos = i; | |
599 | } | |
600 | ||
601 | return pos; | |
602 | } | |
603 | ||
604 | /** | |
605 | * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap | |
fb5eeeee | 606 | * @dst: remapped result |
96b7f341 | 607 | * @src: subset to be remapped |
fb5eeeee PJ |
608 | * @old: defines domain of map |
609 | * @new: defines range of map | |
610 | * @bits: number of bits in each of these bitmaps | |
611 | * | |
612 | * Let @old and @new define a mapping of bit positions, such that | |
613 | * whatever position is held by the n-th set bit in @old is mapped | |
614 | * to the n-th set bit in @new. In the more general case, allowing | |
615 | * for the possibility that the weight 'w' of @new is less than the | |
616 | * weight of @old, map the position of the n-th set bit in @old to | |
617 | * the position of the m-th set bit in @new, where m == n % w. | |
618 | * | |
96b7f341 PJ |
619 | * If either of the @old and @new bitmaps are empty, or if @src and |
620 | * @dst point to the same location, then this routine copies @src | |
621 | * to @dst. | |
fb5eeeee | 622 | * |
96b7f341 PJ |
623 | * The positions of unset bits in @old are mapped to themselves |
624 | * (the identify map). | |
fb5eeeee PJ |
625 | * |
626 | * Apply the above specified mapping to @src, placing the result in | |
627 | * @dst, clearing any bits previously set in @dst. | |
628 | * | |
fb5eeeee PJ |
629 | * For example, lets say that @old has bits 4 through 7 set, and |
630 | * @new has bits 12 through 15 set. This defines the mapping of bit | |
631 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other | |
96b7f341 PJ |
632 | * bit positions unchanged. So if say @src comes into this routine |
633 | * with bits 1, 5 and 7 set, then @dst should leave with bits 1, | |
634 | * 13 and 15 set. | |
fb5eeeee PJ |
635 | */ |
636 | void bitmap_remap(unsigned long *dst, const unsigned long *src, | |
637 | const unsigned long *old, const unsigned long *new, | |
638 | int bits) | |
639 | { | |
96b7f341 | 640 | int oldbit, w; |
fb5eeeee | 641 | |
fb5eeeee PJ |
642 | if (dst == src) /* following doesn't handle inplace remaps */ |
643 | return; | |
fb5eeeee | 644 | bitmap_zero(dst, bits); |
96b7f341 PJ |
645 | |
646 | w = bitmap_weight(new, bits); | |
647 | for (oldbit = find_first_bit(src, bits); | |
648 | oldbit < bits; | |
649 | oldbit = find_next_bit(src, bits, oldbit + 1)) { | |
650 | int n = bitmap_pos_to_ord(old, oldbit, bits); | |
651 | if (n < 0 || w == 0) | |
652 | set_bit(oldbit, dst); /* identity map */ | |
653 | else | |
654 | set_bit(bitmap_ord_to_pos(new, n % w, bits), dst); | |
fb5eeeee PJ |
655 | } |
656 | } | |
657 | EXPORT_SYMBOL(bitmap_remap); | |
658 | ||
659 | /** | |
660 | * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit | |
6e1907ff RD |
661 | * @oldbit: bit position to be mapped |
662 | * @old: defines domain of map | |
663 | * @new: defines range of map | |
664 | * @bits: number of bits in each of these bitmaps | |
fb5eeeee PJ |
665 | * |
666 | * Let @old and @new define a mapping of bit positions, such that | |
667 | * whatever position is held by the n-th set bit in @old is mapped | |
668 | * to the n-th set bit in @new. In the more general case, allowing | |
669 | * for the possibility that the weight 'w' of @new is less than the | |
670 | * weight of @old, map the position of the n-th set bit in @old to | |
671 | * the position of the m-th set bit in @new, where m == n % w. | |
672 | * | |
96b7f341 PJ |
673 | * The positions of unset bits in @old are mapped to themselves |
674 | * (the identify map). | |
fb5eeeee PJ |
675 | * |
676 | * Apply the above specified mapping to bit position @oldbit, returning | |
677 | * the new bit position. | |
678 | * | |
679 | * For example, lets say that @old has bits 4 through 7 set, and | |
680 | * @new has bits 12 through 15 set. This defines the mapping of bit | |
681 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other | |
96b7f341 PJ |
682 | * bit positions unchanged. So if say @oldbit is 5, then this routine |
683 | * returns 13. | |
fb5eeeee PJ |
684 | */ |
685 | int bitmap_bitremap(int oldbit, const unsigned long *old, | |
686 | const unsigned long *new, int bits) | |
687 | { | |
96b7f341 PJ |
688 | int w = bitmap_weight(new, bits); |
689 | int n = bitmap_pos_to_ord(old, oldbit, bits); | |
690 | if (n < 0 || w == 0) | |
691 | return oldbit; | |
692 | else | |
693 | return bitmap_ord_to_pos(new, n % w, bits); | |
fb5eeeee PJ |
694 | } |
695 | EXPORT_SYMBOL(bitmap_bitremap); | |
696 | ||
3cf64b93 PJ |
697 | /* |
698 | * Common code for bitmap_*_region() routines. | |
699 | * bitmap: array of unsigned longs corresponding to the bitmap | |
700 | * pos: the beginning of the region | |
701 | * order: region size (log base 2 of number of bits) | |
702 | * reg_op: operation(s) to perform on that region of bitmap | |
1da177e4 | 703 | * |
3cf64b93 PJ |
704 | * Can set, verify and/or release a region of bits in a bitmap, |
705 | * depending on which combination of REG_OP_* flag bits is set. | |
1da177e4 | 706 | * |
3cf64b93 PJ |
707 | * A region of a bitmap is a sequence of bits in the bitmap, of |
708 | * some size '1 << order' (a power of two), aligned to that same | |
709 | * '1 << order' power of two. | |
710 | * | |
711 | * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). | |
712 | * Returns 0 in all other cases and reg_ops. | |
1da177e4 | 713 | */ |
3cf64b93 PJ |
714 | |
715 | enum { | |
716 | REG_OP_ISFREE, /* true if region is all zero bits */ | |
717 | REG_OP_ALLOC, /* set all bits in region */ | |
718 | REG_OP_RELEASE, /* clear all bits in region */ | |
719 | }; | |
720 | ||
721 | static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op) | |
1da177e4 | 722 | { |
3cf64b93 PJ |
723 | int nbits_reg; /* number of bits in region */ |
724 | int index; /* index first long of region in bitmap */ | |
725 | int offset; /* bit offset region in bitmap[index] */ | |
726 | int nlongs_reg; /* num longs spanned by region in bitmap */ | |
74373c6a | 727 | int nbitsinlong; /* num bits of region in each spanned long */ |
3cf64b93 | 728 | unsigned long mask; /* bitmask for one long of region */ |
74373c6a | 729 | int i; /* scans bitmap by longs */ |
3cf64b93 | 730 | int ret = 0; /* return value */ |
74373c6a | 731 | |
3cf64b93 PJ |
732 | /* |
733 | * Either nlongs_reg == 1 (for small orders that fit in one long) | |
734 | * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) | |
735 | */ | |
736 | nbits_reg = 1 << order; | |
737 | index = pos / BITS_PER_LONG; | |
738 | offset = pos - (index * BITS_PER_LONG); | |
739 | nlongs_reg = BITS_TO_LONGS(nbits_reg); | |
740 | nbitsinlong = min(nbits_reg, BITS_PER_LONG); | |
1da177e4 | 741 | |
3cf64b93 PJ |
742 | /* |
743 | * Can't do "mask = (1UL << nbitsinlong) - 1", as that | |
744 | * overflows if nbitsinlong == BITS_PER_LONG. | |
745 | */ | |
74373c6a | 746 | mask = (1UL << (nbitsinlong - 1)); |
1da177e4 | 747 | mask += mask - 1; |
3cf64b93 | 748 | mask <<= offset; |
1da177e4 | 749 | |
3cf64b93 PJ |
750 | switch (reg_op) { |
751 | case REG_OP_ISFREE: | |
752 | for (i = 0; i < nlongs_reg; i++) { | |
753 | if (bitmap[index + i] & mask) | |
754 | goto done; | |
755 | } | |
756 | ret = 1; /* all bits in region free (zero) */ | |
757 | break; | |
758 | ||
759 | case REG_OP_ALLOC: | |
760 | for (i = 0; i < nlongs_reg; i++) | |
761 | bitmap[index + i] |= mask; | |
762 | break; | |
763 | ||
764 | case REG_OP_RELEASE: | |
765 | for (i = 0; i < nlongs_reg; i++) | |
766 | bitmap[index + i] &= ~mask; | |
767 | break; | |
1da177e4 | 768 | } |
3cf64b93 PJ |
769 | done: |
770 | return ret; | |
771 | } | |
772 | ||
773 | /** | |
774 | * bitmap_find_free_region - find a contiguous aligned mem region | |
775 | * @bitmap: array of unsigned longs corresponding to the bitmap | |
776 | * @bits: number of bits in the bitmap | |
777 | * @order: region size (log base 2 of number of bits) to find | |
778 | * | |
779 | * Find a region of free (zero) bits in a @bitmap of @bits bits and | |
780 | * allocate them (set them to one). Only consider regions of length | |
781 | * a power (@order) of two, aligned to that power of two, which | |
782 | * makes the search algorithm much faster. | |
783 | * | |
784 | * Return the bit offset in bitmap of the allocated region, | |
785 | * or -errno on failure. | |
786 | */ | |
787 | int bitmap_find_free_region(unsigned long *bitmap, int bits, int order) | |
788 | { | |
789 | int pos; /* scans bitmap by regions of size order */ | |
790 | ||
791 | for (pos = 0; pos < bits; pos += (1 << order)) | |
792 | if (__reg_op(bitmap, pos, order, REG_OP_ISFREE)) | |
793 | break; | |
794 | if (pos == bits) | |
795 | return -ENOMEM; | |
796 | __reg_op(bitmap, pos, order, REG_OP_ALLOC); | |
797 | return pos; | |
1da177e4 LT |
798 | } |
799 | EXPORT_SYMBOL(bitmap_find_free_region); | |
800 | ||
801 | /** | |
87e24802 | 802 | * bitmap_release_region - release allocated bitmap region |
3cf64b93 PJ |
803 | * @bitmap: array of unsigned longs corresponding to the bitmap |
804 | * @pos: beginning of bit region to release | |
805 | * @order: region size (log base 2 of number of bits) to release | |
1da177e4 | 806 | * |
72fd4a35 | 807 | * This is the complement to __bitmap_find_free_region() and releases |
1da177e4 | 808 | * the found region (by clearing it in the bitmap). |
3cf64b93 PJ |
809 | * |
810 | * No return value. | |
1da177e4 LT |
811 | */ |
812 | void bitmap_release_region(unsigned long *bitmap, int pos, int order) | |
813 | { | |
3cf64b93 | 814 | __reg_op(bitmap, pos, order, REG_OP_RELEASE); |
1da177e4 LT |
815 | } |
816 | EXPORT_SYMBOL(bitmap_release_region); | |
817 | ||
87e24802 PJ |
818 | /** |
819 | * bitmap_allocate_region - allocate bitmap region | |
3cf64b93 PJ |
820 | * @bitmap: array of unsigned longs corresponding to the bitmap |
821 | * @pos: beginning of bit region to allocate | |
822 | * @order: region size (log base 2 of number of bits) to allocate | |
87e24802 PJ |
823 | * |
824 | * Allocate (set bits in) a specified region of a bitmap. | |
3cf64b93 | 825 | * |
6e1907ff | 826 | * Return 0 on success, or %-EBUSY if specified region wasn't |
87e24802 PJ |
827 | * free (not all bits were zero). |
828 | */ | |
1da177e4 LT |
829 | int bitmap_allocate_region(unsigned long *bitmap, int pos, int order) |
830 | { | |
3cf64b93 PJ |
831 | if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) |
832 | return -EBUSY; | |
833 | __reg_op(bitmap, pos, order, REG_OP_ALLOC); | |
1da177e4 LT |
834 | return 0; |
835 | } | |
836 | EXPORT_SYMBOL(bitmap_allocate_region); |