Commit | Line | Data |
---|---|---|
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 | */ | |
8bc3bcc9 PG |
8 | #include <linux/export.h> |
9 | #include <linux/thread_info.h> | |
1da177e4 LT |
10 | #include <linux/ctype.h> |
11 | #include <linux/errno.h> | |
12 | #include <linux/bitmap.h> | |
13 | #include <linux/bitops.h> | |
14 | #include <asm/uaccess.h> | |
15 | ||
16 | /* | |
17 | * bitmaps provide an array of bits, implemented using an an | |
18 | * array of unsigned longs. The number of valid bits in a | |
19 | * given bitmap does _not_ need to be an exact multiple of | |
20 | * BITS_PER_LONG. | |
21 | * | |
22 | * The possible unused bits in the last, partially used word | |
23 | * of a bitmap are 'don't care'. The implementation makes | |
24 | * no particular effort to keep them zero. It ensures that | |
25 | * their value will not affect the results of any operation. | |
26 | * The bitmap operations that return Boolean (bitmap_empty, | |
27 | * for example) or scalar (bitmap_weight, for example) results | |
28 | * carefully filter out these unused bits from impacting their | |
29 | * results. | |
30 | * | |
31 | * These operations actually hold to a slightly stronger rule: | |
32 | * if you don't input any bitmaps to these ops that have some | |
33 | * unused bits set, then they won't output any set unused bits | |
34 | * in output bitmaps. | |
35 | * | |
36 | * The byte ordering of bitmaps is more natural on little | |
37 | * endian architectures. See the big-endian headers | |
38 | * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h | |
39 | * for the best explanations of this ordering. | |
40 | */ | |
41 | ||
42 | int __bitmap_empty(const unsigned long *bitmap, int bits) | |
43 | { | |
44 | int k, lim = bits/BITS_PER_LONG; | |
45 | for (k = 0; k < lim; ++k) | |
46 | if (bitmap[k]) | |
47 | return 0; | |
48 | ||
49 | if (bits % BITS_PER_LONG) | |
50 | if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) | |
51 | return 0; | |
52 | ||
53 | return 1; | |
54 | } | |
55 | EXPORT_SYMBOL(__bitmap_empty); | |
56 | ||
57 | int __bitmap_full(const unsigned long *bitmap, int bits) | |
58 | { | |
59 | int k, lim = bits/BITS_PER_LONG; | |
60 | for (k = 0; k < lim; ++k) | |
61 | if (~bitmap[k]) | |
62 | return 0; | |
63 | ||
64 | if (bits % BITS_PER_LONG) | |
65 | if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) | |
66 | return 0; | |
67 | ||
68 | return 1; | |
69 | } | |
70 | EXPORT_SYMBOL(__bitmap_full); | |
71 | ||
72 | int __bitmap_equal(const unsigned long *bitmap1, | |
73 | const unsigned long *bitmap2, int bits) | |
74 | { | |
75 | int k, lim = bits/BITS_PER_LONG; | |
76 | for (k = 0; k < lim; ++k) | |
77 | if (bitmap1[k] != bitmap2[k]) | |
78 | return 0; | |
79 | ||
80 | if (bits % BITS_PER_LONG) | |
81 | if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) | |
82 | return 0; | |
83 | ||
84 | return 1; | |
85 | } | |
86 | EXPORT_SYMBOL(__bitmap_equal); | |
87 | ||
88 | void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits) | |
89 | { | |
90 | int k, lim = bits/BITS_PER_LONG; | |
91 | for (k = 0; k < lim; ++k) | |
92 | dst[k] = ~src[k]; | |
93 | ||
94 | if (bits % BITS_PER_LONG) | |
95 | dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits); | |
96 | } | |
97 | EXPORT_SYMBOL(__bitmap_complement); | |
98 | ||
72fd4a35 | 99 | /** |
1da177e4 | 100 | * __bitmap_shift_right - logical right shift of the bits in a bitmap |
05fb6bf0 RD |
101 | * @dst : destination bitmap |
102 | * @src : source bitmap | |
103 | * @shift : shift by this many bits | |
104 | * @bits : bitmap size, in bits | |
1da177e4 LT |
105 | * |
106 | * Shifting right (dividing) means moving bits in the MS -> LS bit | |
107 | * direction. Zeros are fed into the vacated MS positions and the | |
108 | * LS bits shifted off the bottom are lost. | |
109 | */ | |
110 | void __bitmap_shift_right(unsigned long *dst, | |
111 | const unsigned long *src, int shift, int bits) | |
112 | { | |
113 | int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG; | |
114 | int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; | |
115 | unsigned long mask = (1UL << left) - 1; | |
116 | for (k = 0; off + k < lim; ++k) { | |
117 | unsigned long upper, lower; | |
118 | ||
119 | /* | |
120 | * If shift is not word aligned, take lower rem bits of | |
121 | * word above and make them the top rem bits of result. | |
122 | */ | |
123 | if (!rem || off + k + 1 >= lim) | |
124 | upper = 0; | |
125 | else { | |
126 | upper = src[off + k + 1]; | |
127 | if (off + k + 1 == lim - 1 && left) | |
128 | upper &= mask; | |
129 | } | |
130 | lower = src[off + k]; | |
131 | if (left && off + k == lim - 1) | |
132 | lower &= mask; | |
133 | dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem; | |
134 | if (left && k == lim - 1) | |
135 | dst[k] &= mask; | |
136 | } | |
137 | if (off) | |
138 | memset(&dst[lim - off], 0, off*sizeof(unsigned long)); | |
139 | } | |
140 | EXPORT_SYMBOL(__bitmap_shift_right); | |
141 | ||
142 | ||
72fd4a35 | 143 | /** |
1da177e4 | 144 | * __bitmap_shift_left - logical left shift of the bits in a bitmap |
05fb6bf0 RD |
145 | * @dst : destination bitmap |
146 | * @src : source bitmap | |
147 | * @shift : shift by this many bits | |
148 | * @bits : bitmap size, in bits | |
1da177e4 LT |
149 | * |
150 | * Shifting left (multiplying) means moving bits in the LS -> MS | |
151 | * direction. Zeros are fed into the vacated LS bit positions | |
152 | * and those MS bits shifted off the top are lost. | |
153 | */ | |
154 | ||
155 | void __bitmap_shift_left(unsigned long *dst, | |
156 | const unsigned long *src, int shift, int bits) | |
157 | { | |
158 | int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG; | |
159 | int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; | |
160 | for (k = lim - off - 1; k >= 0; --k) { | |
161 | unsigned long upper, lower; | |
162 | ||
163 | /* | |
164 | * If shift is not word aligned, take upper rem bits of | |
165 | * word below and make them the bottom rem bits of result. | |
166 | */ | |
167 | if (rem && k > 0) | |
168 | lower = src[k - 1]; | |
169 | else | |
170 | lower = 0; | |
171 | upper = src[k]; | |
172 | if (left && k == lim - 1) | |
173 | upper &= (1UL << left) - 1; | |
174 | dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem; | |
175 | if (left && k + off == lim - 1) | |
176 | dst[k + off] &= (1UL << left) - 1; | |
177 | } | |
178 | if (off) | |
179 | memset(dst, 0, off*sizeof(unsigned long)); | |
180 | } | |
181 | EXPORT_SYMBOL(__bitmap_shift_left); | |
182 | ||
f4b0373b | 183 | int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, |
1da177e4 LT |
184 | const unsigned long *bitmap2, int bits) |
185 | { | |
186 | int k; | |
187 | int nr = BITS_TO_LONGS(bits); | |
f4b0373b | 188 | unsigned long result = 0; |
1da177e4 LT |
189 | |
190 | for (k = 0; k < nr; k++) | |
f4b0373b LT |
191 | result |= (dst[k] = bitmap1[k] & bitmap2[k]); |
192 | return result != 0; | |
1da177e4 LT |
193 | } |
194 | EXPORT_SYMBOL(__bitmap_and); | |
195 | ||
196 | void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, | |
197 | const unsigned long *bitmap2, int bits) | |
198 | { | |
199 | int k; | |
200 | int nr = BITS_TO_LONGS(bits); | |
201 | ||
202 | for (k = 0; k < nr; k++) | |
203 | dst[k] = bitmap1[k] | bitmap2[k]; | |
204 | } | |
205 | EXPORT_SYMBOL(__bitmap_or); | |
206 | ||
207 | void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, | |
208 | const unsigned long *bitmap2, int bits) | |
209 | { | |
210 | int k; | |
211 | int nr = BITS_TO_LONGS(bits); | |
212 | ||
213 | for (k = 0; k < nr; k++) | |
214 | dst[k] = bitmap1[k] ^ bitmap2[k]; | |
215 | } | |
216 | EXPORT_SYMBOL(__bitmap_xor); | |
217 | ||
f4b0373b | 218 | int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, |
1da177e4 LT |
219 | const unsigned long *bitmap2, int bits) |
220 | { | |
221 | int k; | |
222 | int nr = BITS_TO_LONGS(bits); | |
f4b0373b | 223 | unsigned long result = 0; |
1da177e4 LT |
224 | |
225 | for (k = 0; k < nr; k++) | |
f4b0373b LT |
226 | result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); |
227 | return result != 0; | |
1da177e4 LT |
228 | } |
229 | EXPORT_SYMBOL(__bitmap_andnot); | |
230 | ||
231 | int __bitmap_intersects(const unsigned long *bitmap1, | |
232 | const unsigned long *bitmap2, int bits) | |
233 | { | |
234 | int k, lim = bits/BITS_PER_LONG; | |
235 | for (k = 0; k < lim; ++k) | |
236 | if (bitmap1[k] & bitmap2[k]) | |
237 | return 1; | |
238 | ||
239 | if (bits % BITS_PER_LONG) | |
240 | if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) | |
241 | return 1; | |
242 | return 0; | |
243 | } | |
244 | EXPORT_SYMBOL(__bitmap_intersects); | |
245 | ||
246 | int __bitmap_subset(const unsigned long *bitmap1, | |
247 | const unsigned long *bitmap2, int bits) | |
248 | { | |
249 | int k, lim = bits/BITS_PER_LONG; | |
250 | for (k = 0; k < lim; ++k) | |
251 | if (bitmap1[k] & ~bitmap2[k]) | |
252 | return 0; | |
253 | ||
254 | if (bits % BITS_PER_LONG) | |
255 | if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) | |
256 | return 0; | |
257 | return 1; | |
258 | } | |
259 | EXPORT_SYMBOL(__bitmap_subset); | |
260 | ||
1da177e4 LT |
261 | int __bitmap_weight(const unsigned long *bitmap, int bits) |
262 | { | |
263 | int k, w = 0, lim = bits/BITS_PER_LONG; | |
264 | ||
265 | for (k = 0; k < lim; k++) | |
37d54111 | 266 | w += hweight_long(bitmap[k]); |
1da177e4 LT |
267 | |
268 | if (bits % BITS_PER_LONG) | |
37d54111 | 269 | w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); |
1da177e4 LT |
270 | |
271 | return w; | |
272 | } | |
1da177e4 LT |
273 | EXPORT_SYMBOL(__bitmap_weight); |
274 | ||
c1a2a962 AM |
275 | void bitmap_set(unsigned long *map, int start, int nr) |
276 | { | |
277 | unsigned long *p = map + BIT_WORD(start); | |
278 | const int size = start + nr; | |
279 | int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); | |
280 | unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); | |
281 | ||
282 | while (nr - bits_to_set >= 0) { | |
283 | *p |= mask_to_set; | |
284 | nr -= bits_to_set; | |
285 | bits_to_set = BITS_PER_LONG; | |
286 | mask_to_set = ~0UL; | |
287 | p++; | |
288 | } | |
289 | if (nr) { | |
290 | mask_to_set &= BITMAP_LAST_WORD_MASK(size); | |
291 | *p |= mask_to_set; | |
292 | } | |
293 | } | |
294 | EXPORT_SYMBOL(bitmap_set); | |
295 | ||
296 | void bitmap_clear(unsigned long *map, int start, int nr) | |
297 | { | |
298 | unsigned long *p = map + BIT_WORD(start); | |
299 | const int size = start + nr; | |
300 | int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); | |
301 | unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); | |
302 | ||
303 | while (nr - bits_to_clear >= 0) { | |
304 | *p &= ~mask_to_clear; | |
305 | nr -= bits_to_clear; | |
306 | bits_to_clear = BITS_PER_LONG; | |
307 | mask_to_clear = ~0UL; | |
308 | p++; | |
309 | } | |
310 | if (nr) { | |
311 | mask_to_clear &= BITMAP_LAST_WORD_MASK(size); | |
312 | *p &= ~mask_to_clear; | |
313 | } | |
314 | } | |
315 | EXPORT_SYMBOL(bitmap_clear); | |
316 | ||
317 | /* | |
318 | * bitmap_find_next_zero_area - find a contiguous aligned zero area | |
319 | * @map: The address to base the search on | |
320 | * @size: The bitmap size in bits | |
321 | * @start: The bitnumber to start searching at | |
322 | * @nr: The number of zeroed bits we're looking for | |
323 | * @align_mask: Alignment mask for zero area | |
324 | * | |
325 | * The @align_mask should be one less than a power of 2; the effect is that | |
326 | * the bit offset of all zero areas this function finds is multiples of that | |
327 | * power of 2. A @align_mask of 0 means no alignment is required. | |
328 | */ | |
329 | unsigned long bitmap_find_next_zero_area(unsigned long *map, | |
330 | unsigned long size, | |
331 | unsigned long start, | |
332 | unsigned int nr, | |
333 | unsigned long align_mask) | |
334 | { | |
335 | unsigned long index, end, i; | |
336 | again: | |
337 | index = find_next_zero_bit(map, size, start); | |
338 | ||
339 | /* Align allocation */ | |
340 | index = __ALIGN_MASK(index, align_mask); | |
341 | ||
342 | end = index + nr; | |
343 | if (end > size) | |
344 | return end; | |
345 | i = find_next_bit(map, end, index); | |
346 | if (i < end) { | |
347 | start = i + 1; | |
348 | goto again; | |
349 | } | |
350 | return index; | |
351 | } | |
352 | EXPORT_SYMBOL(bitmap_find_next_zero_area); | |
353 | ||
1da177e4 LT |
354 | /* |
355 | * Bitmap printing & parsing functions: first version by Bill Irwin, | |
356 | * second version by Paul Jackson, third by Joe Korty. | |
357 | */ | |
358 | ||
359 | #define CHUNKSZ 32 | |
360 | #define nbits_to_hold_value(val) fls(val) | |
1da177e4 LT |
361 | #define BASEDEC 10 /* fancier cpuset lists input in decimal */ |
362 | ||
363 | /** | |
364 | * bitmap_scnprintf - convert bitmap to an ASCII hex string. | |
365 | * @buf: byte buffer into which string is placed | |
366 | * @buflen: reserved size of @buf, in bytes | |
367 | * @maskp: pointer to bitmap to convert | |
368 | * @nmaskbits: size of bitmap, in bits | |
369 | * | |
370 | * Exactly @nmaskbits bits are displayed. Hex digits are grouped into | |
371 | * comma-separated sets of eight digits per set. | |
372 | */ | |
373 | int bitmap_scnprintf(char *buf, unsigned int buflen, | |
374 | const unsigned long *maskp, int nmaskbits) | |
375 | { | |
376 | int i, word, bit, len = 0; | |
377 | unsigned long val; | |
378 | const char *sep = ""; | |
379 | int chunksz; | |
380 | u32 chunkmask; | |
381 | ||
382 | chunksz = nmaskbits & (CHUNKSZ - 1); | |
383 | if (chunksz == 0) | |
384 | chunksz = CHUNKSZ; | |
385 | ||
8c0e33c1 | 386 | i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ; |
1da177e4 LT |
387 | for (; i >= 0; i -= CHUNKSZ) { |
388 | chunkmask = ((1ULL << chunksz) - 1); | |
389 | word = i / BITS_PER_LONG; | |
390 | bit = i % BITS_PER_LONG; | |
391 | val = (maskp[word] >> bit) & chunkmask; | |
392 | len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep, | |
393 | (chunksz+3)/4, val); | |
394 | chunksz = CHUNKSZ; | |
395 | sep = ","; | |
396 | } | |
397 | return len; | |
398 | } | |
399 | EXPORT_SYMBOL(bitmap_scnprintf); | |
400 | ||
401 | /** | |
01a3ee2b RC |
402 | * __bitmap_parse - convert an ASCII hex string into a bitmap. |
403 | * @buf: pointer to buffer containing string. | |
404 | * @buflen: buffer size in bytes. If string is smaller than this | |
1da177e4 | 405 | * then it must be terminated with a \0. |
01a3ee2b | 406 | * @is_user: location of buffer, 0 indicates kernel space |
1da177e4 LT |
407 | * @maskp: pointer to bitmap array that will contain result. |
408 | * @nmaskbits: size of bitmap, in bits. | |
409 | * | |
410 | * Commas group hex digits into chunks. Each chunk defines exactly 32 | |
411 | * bits of the resultant bitmask. No chunk may specify a value larger | |
6e1907ff RD |
412 | * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value |
413 | * then leading 0-bits are prepended. %-EINVAL is returned for illegal | |
1da177e4 LT |
414 | * characters and for grouping errors such as "1,,5", ",44", "," and "". |
415 | * Leading and trailing whitespace accepted, but not embedded whitespace. | |
416 | */ | |
01a3ee2b RC |
417 | int __bitmap_parse(const char *buf, unsigned int buflen, |
418 | int is_user, unsigned long *maskp, | |
419 | int nmaskbits) | |
1da177e4 LT |
420 | { |
421 | int c, old_c, totaldigits, ndigits, nchunks, nbits; | |
422 | u32 chunk; | |
b9c321fd | 423 | const char __user __force *ubuf = (const char __user __force *)buf; |
1da177e4 LT |
424 | |
425 | bitmap_zero(maskp, nmaskbits); | |
426 | ||
427 | nchunks = nbits = totaldigits = c = 0; | |
428 | do { | |
429 | chunk = ndigits = 0; | |
430 | ||
431 | /* Get the next chunk of the bitmap */ | |
01a3ee2b | 432 | while (buflen) { |
1da177e4 | 433 | old_c = c; |
01a3ee2b RC |
434 | if (is_user) { |
435 | if (__get_user(c, ubuf++)) | |
436 | return -EFAULT; | |
437 | } | |
438 | else | |
439 | c = *buf++; | |
440 | buflen--; | |
1da177e4 LT |
441 | if (isspace(c)) |
442 | continue; | |
443 | ||
444 | /* | |
445 | * If the last character was a space and the current | |
446 | * character isn't '\0', we've got embedded whitespace. | |
447 | * This is a no-no, so throw an error. | |
448 | */ | |
449 | if (totaldigits && c && isspace(old_c)) | |
450 | return -EINVAL; | |
451 | ||
452 | /* A '\0' or a ',' signal the end of the chunk */ | |
453 | if (c == '\0' || c == ',') | |
454 | break; | |
455 | ||
456 | if (!isxdigit(c)) | |
457 | return -EINVAL; | |
458 | ||
459 | /* | |
460 | * Make sure there are at least 4 free bits in 'chunk'. | |
461 | * If not, this hexdigit will overflow 'chunk', so | |
462 | * throw an error. | |
463 | */ | |
464 | if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) | |
465 | return -EOVERFLOW; | |
466 | ||
66f1991b | 467 | chunk = (chunk << 4) | hex_to_bin(c); |
1da177e4 LT |
468 | ndigits++; totaldigits++; |
469 | } | |
470 | if (ndigits == 0) | |
471 | return -EINVAL; | |
472 | if (nchunks == 0 && chunk == 0) | |
473 | continue; | |
474 | ||
475 | __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); | |
476 | *maskp |= chunk; | |
477 | nchunks++; | |
478 | nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; | |
479 | if (nbits > nmaskbits) | |
480 | return -EOVERFLOW; | |
01a3ee2b | 481 | } while (buflen && c == ','); |
1da177e4 LT |
482 | |
483 | return 0; | |
484 | } | |
01a3ee2b RC |
485 | EXPORT_SYMBOL(__bitmap_parse); |
486 | ||
487 | /** | |
9a86e2ba | 488 | * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap |
01a3ee2b RC |
489 | * |
490 | * @ubuf: pointer to user buffer containing string. | |
491 | * @ulen: buffer size in bytes. If string is smaller than this | |
492 | * then it must be terminated with a \0. | |
493 | * @maskp: pointer to bitmap array that will contain result. | |
494 | * @nmaskbits: size of bitmap, in bits. | |
495 | * | |
496 | * Wrapper for __bitmap_parse(), providing it with user buffer. | |
497 | * | |
498 | * We cannot have this as an inline function in bitmap.h because it needs | |
499 | * linux/uaccess.h to get the access_ok() declaration and this causes | |
500 | * cyclic dependencies. | |
501 | */ | |
502 | int bitmap_parse_user(const char __user *ubuf, | |
503 | unsigned int ulen, unsigned long *maskp, | |
504 | int nmaskbits) | |
505 | { | |
506 | if (!access_ok(VERIFY_READ, ubuf, ulen)) | |
507 | return -EFAULT; | |
b9c321fd HS |
508 | return __bitmap_parse((const char __force *)ubuf, |
509 | ulen, 1, maskp, nmaskbits); | |
510 | ||
01a3ee2b RC |
511 | } |
512 | EXPORT_SYMBOL(bitmap_parse_user); | |
1da177e4 LT |
513 | |
514 | /* | |
515 | * bscnl_emit(buf, buflen, rbot, rtop, bp) | |
516 | * | |
517 | * Helper routine for bitmap_scnlistprintf(). Write decimal number | |
518 | * or range to buf, suppressing output past buf+buflen, with optional | |
519 | * comma-prefix. Return len of what would be written to buf, if it | |
520 | * all fit. | |
521 | */ | |
522 | static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len) | |
523 | { | |
524 | if (len > 0) | |
525 | len += scnprintf(buf + len, buflen - len, ","); | |
526 | if (rbot == rtop) | |
527 | len += scnprintf(buf + len, buflen - len, "%d", rbot); | |
528 | else | |
529 | len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop); | |
530 | return len; | |
531 | } | |
532 | ||
533 | /** | |
534 | * bitmap_scnlistprintf - convert bitmap to list format ASCII string | |
535 | * @buf: byte buffer into which string is placed | |
536 | * @buflen: reserved size of @buf, in bytes | |
537 | * @maskp: pointer to bitmap to convert | |
538 | * @nmaskbits: size of bitmap, in bits | |
539 | * | |
540 | * Output format is a comma-separated list of decimal numbers and | |
541 | * ranges. Consecutively set bits are shown as two hyphen-separated | |
542 | * decimal numbers, the smallest and largest bit numbers set in | |
543 | * the range. Output format is compatible with the format | |
544 | * accepted as input by bitmap_parselist(). | |
545 | * | |
546 | * The return value is the number of characters which would be | |
547 | * generated for the given input, excluding the trailing '\0', as | |
548 | * per ISO C99. | |
549 | */ | |
550 | int bitmap_scnlistprintf(char *buf, unsigned int buflen, | |
551 | const unsigned long *maskp, int nmaskbits) | |
552 | { | |
553 | int len = 0; | |
554 | /* current bit is 'cur', most recently seen range is [rbot, rtop] */ | |
555 | int cur, rbot, rtop; | |
556 | ||
0b030c2c AK |
557 | if (buflen == 0) |
558 | return 0; | |
559 | buf[0] = 0; | |
560 | ||
1da177e4 LT |
561 | rbot = cur = find_first_bit(maskp, nmaskbits); |
562 | while (cur < nmaskbits) { | |
563 | rtop = cur; | |
564 | cur = find_next_bit(maskp, nmaskbits, cur+1); | |
565 | if (cur >= nmaskbits || cur > rtop + 1) { | |
566 | len = bscnl_emit(buf, buflen, rbot, rtop, len); | |
567 | rbot = cur; | |
568 | } | |
569 | } | |
570 | return len; | |
571 | } | |
572 | EXPORT_SYMBOL(bitmap_scnlistprintf); | |
573 | ||
574 | /** | |
4b060420 | 575 | * __bitmap_parselist - convert list format ASCII string to bitmap |
b0825ee3 | 576 | * @buf: read nul-terminated user string from this buffer |
4b060420 MT |
577 | * @buflen: buffer size in bytes. If string is smaller than this |
578 | * then it must be terminated with a \0. | |
579 | * @is_user: location of buffer, 0 indicates kernel space | |
6e1907ff | 580 | * @maskp: write resulting mask here |
1da177e4 LT |
581 | * @nmaskbits: number of bits in mask to be written |
582 | * | |
583 | * Input format is a comma-separated list of decimal numbers and | |
584 | * ranges. Consecutively set bits are shown as two hyphen-separated | |
585 | * decimal numbers, the smallest and largest bit numbers set in | |
586 | * the range. | |
587 | * | |
6e1907ff RD |
588 | * Returns 0 on success, -errno on invalid input strings. |
589 | * Error values: | |
590 | * %-EINVAL: second number in range smaller than first | |
591 | * %-EINVAL: invalid character in string | |
592 | * %-ERANGE: bit number specified too large for mask | |
1da177e4 | 593 | */ |
4b060420 MT |
594 | static int __bitmap_parselist(const char *buf, unsigned int buflen, |
595 | int is_user, unsigned long *maskp, | |
596 | int nmaskbits) | |
1da177e4 LT |
597 | { |
598 | unsigned a, b; | |
4b060420 | 599 | int c, old_c, totaldigits; |
b9c321fd | 600 | const char __user __force *ubuf = (const char __user __force *)buf; |
4b060420 | 601 | int exp_digit, in_range; |
1da177e4 | 602 | |
4b060420 | 603 | totaldigits = c = 0; |
1da177e4 LT |
604 | bitmap_zero(maskp, nmaskbits); |
605 | do { | |
4b060420 MT |
606 | exp_digit = 1; |
607 | in_range = 0; | |
608 | a = b = 0; | |
609 | ||
610 | /* Get the next cpu# or a range of cpu#'s */ | |
611 | while (buflen) { | |
612 | old_c = c; | |
613 | if (is_user) { | |
614 | if (__get_user(c, ubuf++)) | |
615 | return -EFAULT; | |
616 | } else | |
617 | c = *buf++; | |
618 | buflen--; | |
619 | if (isspace(c)) | |
620 | continue; | |
621 | ||
622 | /* | |
623 | * If the last character was a space and the current | |
624 | * character isn't '\0', we've got embedded whitespace. | |
625 | * This is a no-no, so throw an error. | |
626 | */ | |
627 | if (totaldigits && c && isspace(old_c)) | |
628 | return -EINVAL; | |
629 | ||
630 | /* A '\0' or a ',' signal the end of a cpu# or range */ | |
631 | if (c == '\0' || c == ',') | |
632 | break; | |
633 | ||
634 | if (c == '-') { | |
635 | if (exp_digit || in_range) | |
636 | return -EINVAL; | |
637 | b = 0; | |
638 | in_range = 1; | |
639 | exp_digit = 1; | |
640 | continue; | |
641 | } | |
642 | ||
643 | if (!isdigit(c)) | |
1da177e4 | 644 | return -EINVAL; |
4b060420 MT |
645 | |
646 | b = b * 10 + (c - '0'); | |
647 | if (!in_range) | |
648 | a = b; | |
649 | exp_digit = 0; | |
650 | totaldigits++; | |
1da177e4 LT |
651 | } |
652 | if (!(a <= b)) | |
653 | return -EINVAL; | |
654 | if (b >= nmaskbits) | |
655 | return -ERANGE; | |
656 | while (a <= b) { | |
657 | set_bit(a, maskp); | |
658 | a++; | |
659 | } | |
4b060420 | 660 | } while (buflen && c == ','); |
1da177e4 LT |
661 | return 0; |
662 | } | |
4b060420 MT |
663 | |
664 | int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) | |
665 | { | |
666 | char *nl = strchr(bp, '\n'); | |
667 | int len; | |
668 | ||
669 | if (nl) | |
670 | len = nl - bp; | |
671 | else | |
672 | len = strlen(bp); | |
673 | ||
674 | return __bitmap_parselist(bp, len, 0, maskp, nmaskbits); | |
675 | } | |
1da177e4 LT |
676 | EXPORT_SYMBOL(bitmap_parselist); |
677 | ||
4b060420 MT |
678 | |
679 | /** | |
680 | * bitmap_parselist_user() | |
681 | * | |
682 | * @ubuf: pointer to user buffer containing string. | |
683 | * @ulen: buffer size in bytes. If string is smaller than this | |
684 | * then it must be terminated with a \0. | |
685 | * @maskp: pointer to bitmap array that will contain result. | |
686 | * @nmaskbits: size of bitmap, in bits. | |
687 | * | |
688 | * Wrapper for bitmap_parselist(), providing it with user buffer. | |
689 | * | |
690 | * We cannot have this as an inline function in bitmap.h because it needs | |
691 | * linux/uaccess.h to get the access_ok() declaration and this causes | |
692 | * cyclic dependencies. | |
693 | */ | |
694 | int bitmap_parselist_user(const char __user *ubuf, | |
695 | unsigned int ulen, unsigned long *maskp, | |
696 | int nmaskbits) | |
697 | { | |
698 | if (!access_ok(VERIFY_READ, ubuf, ulen)) | |
699 | return -EFAULT; | |
b9c321fd | 700 | return __bitmap_parselist((const char __force *)ubuf, |
4b060420 MT |
701 | ulen, 1, maskp, nmaskbits); |
702 | } | |
703 | EXPORT_SYMBOL(bitmap_parselist_user); | |
704 | ||
705 | ||
72fd4a35 | 706 | /** |
9a86e2ba | 707 | * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap |
fb5eeeee PJ |
708 | * @buf: pointer to a bitmap |
709 | * @pos: a bit position in @buf (0 <= @pos < @bits) | |
710 | * @bits: number of valid bit positions in @buf | |
711 | * | |
712 | * Map the bit at position @pos in @buf (of length @bits) to the | |
713 | * ordinal of which set bit it is. If it is not set or if @pos | |
96b7f341 | 714 | * is not a valid bit position, map to -1. |
fb5eeeee PJ |
715 | * |
716 | * If for example, just bits 4 through 7 are set in @buf, then @pos | |
717 | * values 4 through 7 will get mapped to 0 through 3, respectively, | |
718 | * and other @pos values will get mapped to 0. When @pos value 7 | |
719 | * gets mapped to (returns) @ord value 3 in this example, that means | |
720 | * that bit 7 is the 3rd (starting with 0th) set bit in @buf. | |
721 | * | |
722 | * The bit positions 0 through @bits are valid positions in @buf. | |
723 | */ | |
724 | static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits) | |
725 | { | |
96b7f341 | 726 | int i, ord; |
fb5eeeee | 727 | |
96b7f341 PJ |
728 | if (pos < 0 || pos >= bits || !test_bit(pos, buf)) |
729 | return -1; | |
fb5eeeee | 730 | |
96b7f341 PJ |
731 | i = find_first_bit(buf, bits); |
732 | ord = 0; | |
733 | while (i < pos) { | |
734 | i = find_next_bit(buf, bits, i + 1); | |
735 | ord++; | |
fb5eeeee | 736 | } |
96b7f341 PJ |
737 | BUG_ON(i != pos); |
738 | ||
fb5eeeee PJ |
739 | return ord; |
740 | } | |
741 | ||
742 | /** | |
9a86e2ba | 743 | * bitmap_ord_to_pos - find position of n-th set bit in bitmap |
fb5eeeee PJ |
744 | * @buf: pointer to bitmap |
745 | * @ord: ordinal bit position (n-th set bit, n >= 0) | |
746 | * @bits: number of valid bit positions in @buf | |
747 | * | |
748 | * Map the ordinal offset of bit @ord in @buf to its position in @buf. | |
96b7f341 PJ |
749 | * Value of @ord should be in range 0 <= @ord < weight(buf), else |
750 | * results are undefined. | |
fb5eeeee PJ |
751 | * |
752 | * If for example, just bits 4 through 7 are set in @buf, then @ord | |
753 | * values 0 through 3 will get mapped to 4 through 7, respectively, | |
96b7f341 | 754 | * and all other @ord values return undefined values. When @ord value 3 |
fb5eeeee PJ |
755 | * gets mapped to (returns) @pos value 7 in this example, that means |
756 | * that the 3rd set bit (starting with 0th) is at position 7 in @buf. | |
757 | * | |
758 | * The bit positions 0 through @bits are valid positions in @buf. | |
759 | */ | |
778d3b0f | 760 | int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) |
fb5eeeee PJ |
761 | { |
762 | int pos = 0; | |
763 | ||
764 | if (ord >= 0 && ord < bits) { | |
765 | int i; | |
766 | ||
767 | for (i = find_first_bit(buf, bits); | |
768 | i < bits && ord > 0; | |
769 | i = find_next_bit(buf, bits, i + 1)) | |
770 | ord--; | |
771 | if (i < bits && ord == 0) | |
772 | pos = i; | |
773 | } | |
774 | ||
775 | return pos; | |
776 | } | |
777 | ||
778 | /** | |
779 | * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap | |
fb5eeeee | 780 | * @dst: remapped result |
96b7f341 | 781 | * @src: subset to be remapped |
fb5eeeee PJ |
782 | * @old: defines domain of map |
783 | * @new: defines range of map | |
784 | * @bits: number of bits in each of these bitmaps | |
785 | * | |
786 | * Let @old and @new define a mapping of bit positions, such that | |
787 | * whatever position is held by the n-th set bit in @old is mapped | |
788 | * to the n-th set bit in @new. In the more general case, allowing | |
789 | * for the possibility that the weight 'w' of @new is less than the | |
790 | * weight of @old, map the position of the n-th set bit in @old to | |
791 | * the position of the m-th set bit in @new, where m == n % w. | |
792 | * | |
96b7f341 PJ |
793 | * If either of the @old and @new bitmaps are empty, or if @src and |
794 | * @dst point to the same location, then this routine copies @src | |
795 | * to @dst. | |
fb5eeeee | 796 | * |
96b7f341 PJ |
797 | * The positions of unset bits in @old are mapped to themselves |
798 | * (the identify map). | |
fb5eeeee PJ |
799 | * |
800 | * Apply the above specified mapping to @src, placing the result in | |
801 | * @dst, clearing any bits previously set in @dst. | |
802 | * | |
fb5eeeee PJ |
803 | * For example, lets say that @old has bits 4 through 7 set, and |
804 | * @new has bits 12 through 15 set. This defines the mapping of bit | |
805 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other | |
96b7f341 PJ |
806 | * bit positions unchanged. So if say @src comes into this routine |
807 | * with bits 1, 5 and 7 set, then @dst should leave with bits 1, | |
808 | * 13 and 15 set. | |
fb5eeeee PJ |
809 | */ |
810 | void bitmap_remap(unsigned long *dst, const unsigned long *src, | |
811 | const unsigned long *old, const unsigned long *new, | |
812 | int bits) | |
813 | { | |
96b7f341 | 814 | int oldbit, w; |
fb5eeeee | 815 | |
fb5eeeee PJ |
816 | if (dst == src) /* following doesn't handle inplace remaps */ |
817 | return; | |
fb5eeeee | 818 | bitmap_zero(dst, bits); |
96b7f341 PJ |
819 | |
820 | w = bitmap_weight(new, bits); | |
08564fb7 | 821 | for_each_set_bit(oldbit, src, bits) { |
96b7f341 | 822 | int n = bitmap_pos_to_ord(old, oldbit, bits); |
08564fb7 | 823 | |
96b7f341 PJ |
824 | if (n < 0 || w == 0) |
825 | set_bit(oldbit, dst); /* identity map */ | |
826 | else | |
827 | set_bit(bitmap_ord_to_pos(new, n % w, bits), dst); | |
fb5eeeee PJ |
828 | } |
829 | } | |
830 | EXPORT_SYMBOL(bitmap_remap); | |
831 | ||
832 | /** | |
833 | * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit | |
6e1907ff RD |
834 | * @oldbit: bit position to be mapped |
835 | * @old: defines domain of map | |
836 | * @new: defines range of map | |
837 | * @bits: number of bits in each of these bitmaps | |
fb5eeeee PJ |
838 | * |
839 | * Let @old and @new define a mapping of bit positions, such that | |
840 | * whatever position is held by the n-th set bit in @old is mapped | |
841 | * to the n-th set bit in @new. In the more general case, allowing | |
842 | * for the possibility that the weight 'w' of @new is less than the | |
843 | * weight of @old, map the position of the n-th set bit in @old to | |
844 | * the position of the m-th set bit in @new, where m == n % w. | |
845 | * | |
96b7f341 PJ |
846 | * The positions of unset bits in @old are mapped to themselves |
847 | * (the identify map). | |
fb5eeeee PJ |
848 | * |
849 | * Apply the above specified mapping to bit position @oldbit, returning | |
850 | * the new bit position. | |
851 | * | |
852 | * For example, lets say that @old has bits 4 through 7 set, and | |
853 | * @new has bits 12 through 15 set. This defines the mapping of bit | |
854 | * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other | |
96b7f341 PJ |
855 | * bit positions unchanged. So if say @oldbit is 5, then this routine |
856 | * returns 13. | |
fb5eeeee PJ |
857 | */ |
858 | int bitmap_bitremap(int oldbit, const unsigned long *old, | |
859 | const unsigned long *new, int bits) | |
860 | { | |
96b7f341 PJ |
861 | int w = bitmap_weight(new, bits); |
862 | int n = bitmap_pos_to_ord(old, oldbit, bits); | |
863 | if (n < 0 || w == 0) | |
864 | return oldbit; | |
865 | else | |
866 | return bitmap_ord_to_pos(new, n % w, bits); | |
fb5eeeee PJ |
867 | } |
868 | EXPORT_SYMBOL(bitmap_bitremap); | |
869 | ||
7ea931c9 PJ |
870 | /** |
871 | * bitmap_onto - translate one bitmap relative to another | |
872 | * @dst: resulting translated bitmap | |
873 | * @orig: original untranslated bitmap | |
874 | * @relmap: bitmap relative to which translated | |
875 | * @bits: number of bits in each of these bitmaps | |
876 | * | |
877 | * Set the n-th bit of @dst iff there exists some m such that the | |
878 | * n-th bit of @relmap is set, the m-th bit of @orig is set, and | |
879 | * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. | |
880 | * (If you understood the previous sentence the first time your | |
881 | * read it, you're overqualified for your current job.) | |
882 | * | |
883 | * In other words, @orig is mapped onto (surjectively) @dst, | |
884 | * using the the map { <n, m> | the n-th bit of @relmap is the | |
885 | * m-th set bit of @relmap }. | |
886 | * | |
887 | * Any set bits in @orig above bit number W, where W is the | |
888 | * weight of (number of set bits in) @relmap are mapped nowhere. | |
889 | * In particular, if for all bits m set in @orig, m >= W, then | |
890 | * @dst will end up empty. In situations where the possibility | |
891 | * of such an empty result is not desired, one way to avoid it is | |
892 | * to use the bitmap_fold() operator, below, to first fold the | |
893 | * @orig bitmap over itself so that all its set bits x are in the | |
894 | * range 0 <= x < W. The bitmap_fold() operator does this by | |
895 | * setting the bit (m % W) in @dst, for each bit (m) set in @orig. | |
896 | * | |
897 | * Example [1] for bitmap_onto(): | |
898 | * Let's say @relmap has bits 30-39 set, and @orig has bits | |
899 | * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, | |
900 | * @dst will have bits 31, 33, 35, 37 and 39 set. | |
901 | * | |
902 | * When bit 0 is set in @orig, it means turn on the bit in | |
903 | * @dst corresponding to whatever is the first bit (if any) | |
904 | * that is turned on in @relmap. Since bit 0 was off in the | |
905 | * above example, we leave off that bit (bit 30) in @dst. | |
906 | * | |
907 | * When bit 1 is set in @orig (as in the above example), it | |
908 | * means turn on the bit in @dst corresponding to whatever | |
909 | * is the second bit that is turned on in @relmap. The second | |
910 | * bit in @relmap that was turned on in the above example was | |
911 | * bit 31, so we turned on bit 31 in @dst. | |
912 | * | |
913 | * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, | |
914 | * because they were the 4th, 6th, 8th and 10th set bits | |
915 | * set in @relmap, and the 4th, 6th, 8th and 10th bits of | |
916 | * @orig (i.e. bits 3, 5, 7 and 9) were also set. | |
917 | * | |
918 | * When bit 11 is set in @orig, it means turn on the bit in | |
25985edc | 919 | * @dst corresponding to whatever is the twelfth bit that is |
7ea931c9 PJ |
920 | * turned on in @relmap. In the above example, there were |
921 | * only ten bits turned on in @relmap (30..39), so that bit | |
922 | * 11 was set in @orig had no affect on @dst. | |
923 | * | |
924 | * Example [2] for bitmap_fold() + bitmap_onto(): | |
925 | * Let's say @relmap has these ten bits set: | |
926 | * 40 41 42 43 45 48 53 61 74 95 | |
927 | * (for the curious, that's 40 plus the first ten terms of the | |
928 | * Fibonacci sequence.) | |
929 | * | |
930 | * Further lets say we use the following code, invoking | |
931 | * bitmap_fold() then bitmap_onto, as suggested above to | |
932 | * avoid the possitility of an empty @dst result: | |
933 | * | |
934 | * unsigned long *tmp; // a temporary bitmap's bits | |
935 | * | |
936 | * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); | |
937 | * bitmap_onto(dst, tmp, relmap, bits); | |
938 | * | |
939 | * Then this table shows what various values of @dst would be, for | |
940 | * various @orig's. I list the zero-based positions of each set bit. | |
941 | * The tmp column shows the intermediate result, as computed by | |
942 | * using bitmap_fold() to fold the @orig bitmap modulo ten | |
943 | * (the weight of @relmap). | |
944 | * | |
945 | * @orig tmp @dst | |
946 | * 0 0 40 | |
947 | * 1 1 41 | |
948 | * 9 9 95 | |
949 | * 10 0 40 (*) | |
950 | * 1 3 5 7 1 3 5 7 41 43 48 61 | |
951 | * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 | |
952 | * 0 9 18 27 0 9 8 7 40 61 74 95 | |
953 | * 0 10 20 30 0 40 | |
954 | * 0 11 22 33 0 1 2 3 40 41 42 43 | |
955 | * 0 12 24 36 0 2 4 6 40 42 45 53 | |
956 | * 78 102 211 1 2 8 41 42 74 (*) | |
957 | * | |
958 | * (*) For these marked lines, if we hadn't first done bitmap_fold() | |
959 | * into tmp, then the @dst result would have been empty. | |
960 | * | |
961 | * If either of @orig or @relmap is empty (no set bits), then @dst | |
962 | * will be returned empty. | |
963 | * | |
964 | * If (as explained above) the only set bits in @orig are in positions | |
965 | * m where m >= W, (where W is the weight of @relmap) then @dst will | |
966 | * once again be returned empty. | |
967 | * | |
968 | * All bits in @dst not set by the above rule are cleared. | |
969 | */ | |
970 | void bitmap_onto(unsigned long *dst, const unsigned long *orig, | |
971 | const unsigned long *relmap, int bits) | |
972 | { | |
973 | int n, m; /* same meaning as in above comment */ | |
974 | ||
975 | if (dst == orig) /* following doesn't handle inplace mappings */ | |
976 | return; | |
977 | bitmap_zero(dst, bits); | |
978 | ||
979 | /* | |
980 | * The following code is a more efficient, but less | |
981 | * obvious, equivalent to the loop: | |
982 | * for (m = 0; m < bitmap_weight(relmap, bits); m++) { | |
983 | * n = bitmap_ord_to_pos(orig, m, bits); | |
984 | * if (test_bit(m, orig)) | |
985 | * set_bit(n, dst); | |
986 | * } | |
987 | */ | |
988 | ||
989 | m = 0; | |
08564fb7 | 990 | for_each_set_bit(n, relmap, bits) { |
7ea931c9 PJ |
991 | /* m == bitmap_pos_to_ord(relmap, n, bits) */ |
992 | if (test_bit(m, orig)) | |
993 | set_bit(n, dst); | |
994 | m++; | |
995 | } | |
996 | } | |
997 | EXPORT_SYMBOL(bitmap_onto); | |
998 | ||
999 | /** | |
1000 | * bitmap_fold - fold larger bitmap into smaller, modulo specified size | |
1001 | * @dst: resulting smaller bitmap | |
1002 | * @orig: original larger bitmap | |
1003 | * @sz: specified size | |
1004 | * @bits: number of bits in each of these bitmaps | |
1005 | * | |
1006 | * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. | |
1007 | * Clear all other bits in @dst. See further the comment and | |
1008 | * Example [2] for bitmap_onto() for why and how to use this. | |
1009 | */ | |
1010 | void bitmap_fold(unsigned long *dst, const unsigned long *orig, | |
1011 | int sz, int bits) | |
1012 | { | |
1013 | int oldbit; | |
1014 | ||
1015 | if (dst == orig) /* following doesn't handle inplace mappings */ | |
1016 | return; | |
1017 | bitmap_zero(dst, bits); | |
1018 | ||
08564fb7 | 1019 | for_each_set_bit(oldbit, orig, bits) |
7ea931c9 PJ |
1020 | set_bit(oldbit % sz, dst); |
1021 | } | |
1022 | EXPORT_SYMBOL(bitmap_fold); | |
1023 | ||
3cf64b93 PJ |
1024 | /* |
1025 | * Common code for bitmap_*_region() routines. | |
1026 | * bitmap: array of unsigned longs corresponding to the bitmap | |
1027 | * pos: the beginning of the region | |
1028 | * order: region size (log base 2 of number of bits) | |
1029 | * reg_op: operation(s) to perform on that region of bitmap | |
1da177e4 | 1030 | * |
3cf64b93 PJ |
1031 | * Can set, verify and/or release a region of bits in a bitmap, |
1032 | * depending on which combination of REG_OP_* flag bits is set. | |
1da177e4 | 1033 | * |
3cf64b93 PJ |
1034 | * A region of a bitmap is a sequence of bits in the bitmap, of |
1035 | * some size '1 << order' (a power of two), aligned to that same | |
1036 | * '1 << order' power of two. | |
1037 | * | |
1038 | * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). | |
1039 | * Returns 0 in all other cases and reg_ops. | |
1da177e4 | 1040 | */ |
3cf64b93 PJ |
1041 | |
1042 | enum { | |
1043 | REG_OP_ISFREE, /* true if region is all zero bits */ | |
1044 | REG_OP_ALLOC, /* set all bits in region */ | |
1045 | REG_OP_RELEASE, /* clear all bits in region */ | |
1046 | }; | |
1047 | ||
1048 | static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op) | |
1da177e4 | 1049 | { |
3cf64b93 PJ |
1050 | int nbits_reg; /* number of bits in region */ |
1051 | int index; /* index first long of region in bitmap */ | |
1052 | int offset; /* bit offset region in bitmap[index] */ | |
1053 | int nlongs_reg; /* num longs spanned by region in bitmap */ | |
74373c6a | 1054 | int nbitsinlong; /* num bits of region in each spanned long */ |
3cf64b93 | 1055 | unsigned long mask; /* bitmask for one long of region */ |
74373c6a | 1056 | int i; /* scans bitmap by longs */ |
3cf64b93 | 1057 | int ret = 0; /* return value */ |
74373c6a | 1058 | |
3cf64b93 PJ |
1059 | /* |
1060 | * Either nlongs_reg == 1 (for small orders that fit in one long) | |
1061 | * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) | |
1062 | */ | |
1063 | nbits_reg = 1 << order; | |
1064 | index = pos / BITS_PER_LONG; | |
1065 | offset = pos - (index * BITS_PER_LONG); | |
1066 | nlongs_reg = BITS_TO_LONGS(nbits_reg); | |
1067 | nbitsinlong = min(nbits_reg, BITS_PER_LONG); | |
1da177e4 | 1068 | |
3cf64b93 PJ |
1069 | /* |
1070 | * Can't do "mask = (1UL << nbitsinlong) - 1", as that | |
1071 | * overflows if nbitsinlong == BITS_PER_LONG. | |
1072 | */ | |
74373c6a | 1073 | mask = (1UL << (nbitsinlong - 1)); |
1da177e4 | 1074 | mask += mask - 1; |
3cf64b93 | 1075 | mask <<= offset; |
1da177e4 | 1076 | |
3cf64b93 PJ |
1077 | switch (reg_op) { |
1078 | case REG_OP_ISFREE: | |
1079 | for (i = 0; i < nlongs_reg; i++) { | |
1080 | if (bitmap[index + i] & mask) | |
1081 | goto done; | |
1082 | } | |
1083 | ret = 1; /* all bits in region free (zero) */ | |
1084 | break; | |
1085 | ||
1086 | case REG_OP_ALLOC: | |
1087 | for (i = 0; i < nlongs_reg; i++) | |
1088 | bitmap[index + i] |= mask; | |
1089 | break; | |
1090 | ||
1091 | case REG_OP_RELEASE: | |
1092 | for (i = 0; i < nlongs_reg; i++) | |
1093 | bitmap[index + i] &= ~mask; | |
1094 | break; | |
1da177e4 | 1095 | } |
3cf64b93 PJ |
1096 | done: |
1097 | return ret; | |
1098 | } | |
1099 | ||
1100 | /** | |
1101 | * bitmap_find_free_region - find a contiguous aligned mem region | |
1102 | * @bitmap: array of unsigned longs corresponding to the bitmap | |
1103 | * @bits: number of bits in the bitmap | |
1104 | * @order: region size (log base 2 of number of bits) to find | |
1105 | * | |
1106 | * Find a region of free (zero) bits in a @bitmap of @bits bits and | |
1107 | * allocate them (set them to one). Only consider regions of length | |
1108 | * a power (@order) of two, aligned to that power of two, which | |
1109 | * makes the search algorithm much faster. | |
1110 | * | |
1111 | * Return the bit offset in bitmap of the allocated region, | |
1112 | * or -errno on failure. | |
1113 | */ | |
1114 | int bitmap_find_free_region(unsigned long *bitmap, int bits, int order) | |
1115 | { | |
aa8e4fc6 LT |
1116 | int pos, end; /* scans bitmap by regions of size order */ |
1117 | ||
1118 | for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) { | |
1119 | if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) | |
1120 | continue; | |
1121 | __reg_op(bitmap, pos, order, REG_OP_ALLOC); | |
1122 | return pos; | |
1123 | } | |
1124 | return -ENOMEM; | |
1da177e4 LT |
1125 | } |
1126 | EXPORT_SYMBOL(bitmap_find_free_region); | |
1127 | ||
1128 | /** | |
87e24802 | 1129 | * bitmap_release_region - release allocated bitmap region |
3cf64b93 PJ |
1130 | * @bitmap: array of unsigned longs corresponding to the bitmap |
1131 | * @pos: beginning of bit region to release | |
1132 | * @order: region size (log base 2 of number of bits) to release | |
1da177e4 | 1133 | * |
72fd4a35 | 1134 | * This is the complement to __bitmap_find_free_region() and releases |
1da177e4 | 1135 | * the found region (by clearing it in the bitmap). |
3cf64b93 PJ |
1136 | * |
1137 | * No return value. | |
1da177e4 LT |
1138 | */ |
1139 | void bitmap_release_region(unsigned long *bitmap, int pos, int order) | |
1140 | { | |
3cf64b93 | 1141 | __reg_op(bitmap, pos, order, REG_OP_RELEASE); |
1da177e4 LT |
1142 | } |
1143 | EXPORT_SYMBOL(bitmap_release_region); | |
1144 | ||
87e24802 PJ |
1145 | /** |
1146 | * bitmap_allocate_region - allocate bitmap region | |
3cf64b93 PJ |
1147 | * @bitmap: array of unsigned longs corresponding to the bitmap |
1148 | * @pos: beginning of bit region to allocate | |
1149 | * @order: region size (log base 2 of number of bits) to allocate | |
87e24802 PJ |
1150 | * |
1151 | * Allocate (set bits in) a specified region of a bitmap. | |
3cf64b93 | 1152 | * |
6e1907ff | 1153 | * Return 0 on success, or %-EBUSY if specified region wasn't |
87e24802 PJ |
1154 | * free (not all bits were zero). |
1155 | */ | |
1da177e4 LT |
1156 | int bitmap_allocate_region(unsigned long *bitmap, int pos, int order) |
1157 | { | |
3cf64b93 PJ |
1158 | if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) |
1159 | return -EBUSY; | |
1160 | __reg_op(bitmap, pos, order, REG_OP_ALLOC); | |
1da177e4 LT |
1161 | return 0; |
1162 | } | |
1163 | EXPORT_SYMBOL(bitmap_allocate_region); | |
ccbe329b DV |
1164 | |
1165 | /** | |
1166 | * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. | |
1167 | * @dst: destination buffer | |
1168 | * @src: bitmap to copy | |
1169 | * @nbits: number of bits in the bitmap | |
1170 | * | |
1171 | * Require nbits % BITS_PER_LONG == 0. | |
1172 | */ | |
1173 | void bitmap_copy_le(void *dst, const unsigned long *src, int nbits) | |
1174 | { | |
1175 | unsigned long *d = dst; | |
1176 | int i; | |
1177 | ||
1178 | for (i = 0; i < nbits/BITS_PER_LONG; i++) { | |
1179 | if (BITS_PER_LONG == 64) | |
1180 | d[i] = cpu_to_le64(src[i]); | |
1181 | else | |
1182 | d[i] = cpu_to_le32(src[i]); | |
1183 | } | |
1184 | } | |
1185 | EXPORT_SYMBOL(bitmap_copy_le); |