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