Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/lib/bitmap.c

  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] = lower >> rem;
135                 if (rem)
136                         dst[k] |= upper << (BITS_PER_LONG - rem);
137                 if (left && k == lim - 1)
138                         dst[k] &= mask;
139         }
140         if (off)
141                 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
142 }
143 EXPORT_SYMBOL(__bitmap_shift_right);
144 
145 
146 /**
147  * __bitmap_shift_left - logical left shift of the bits in a bitmap
148  *   @dst : destination bitmap
149  *   @src : source bitmap
150  *   @shift : shift by this many bits
151  *   @bits : bitmap size, in bits
152  *
153  * Shifting left (multiplying) means moving bits in the LS -> MS
154  * direction.  Zeros are fed into the vacated LS bit positions
155  * and those MS bits shifted off the top are lost.
156  */
157 
158 void __bitmap_shift_left(unsigned long *dst,
159                         const unsigned long *src, int shift, int bits)
160 {
161         int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
162         int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
163         for (k = lim - off - 1; k >= 0; --k) {
164                 unsigned long upper, lower;
165 
166                 /*
167                  * If shift is not word aligned, take upper rem bits of
168                  * word below and make them the bottom rem bits of result.
169                  */
170                 if (rem && k > 0)
171                         lower = src[k - 1];
172                 else
173                         lower = 0;
174                 upper = src[k];
175                 if (left && k == lim - 1)
176                         upper &= (1UL << left) - 1;
177                 dst[k + off] = upper << rem;
178                 if (rem)
179                         dst[k + off] |= lower >> (BITS_PER_LONG - rem);
180                 if (left && k + off == lim - 1)
181                         dst[k + off] &= (1UL << left) - 1;
182         }
183         if (off)
184                 memset(dst, 0, off*sizeof(unsigned long));
185 }
186 EXPORT_SYMBOL(__bitmap_shift_left);
187 
188 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
189                                 const unsigned long *bitmap2, unsigned int bits)
190 {
191         unsigned int k;
192         unsigned int lim = bits/BITS_PER_LONG;
193         unsigned long result = 0;
194 
195         for (k = 0; k < lim; k++)
196                 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
197         if (bits % BITS_PER_LONG)
198                 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
199                            BITMAP_LAST_WORD_MASK(bits));
200         return result != 0;
201 }
202 EXPORT_SYMBOL(__bitmap_and);
203 
204 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
205                                 const unsigned long *bitmap2, unsigned int bits)
206 {
207         unsigned int k;
208         unsigned int nr = BITS_TO_LONGS(bits);
209 
210         for (k = 0; k < nr; k++)
211                 dst[k] = bitmap1[k] | bitmap2[k];
212 }
213 EXPORT_SYMBOL(__bitmap_or);
214 
215 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
216                                 const unsigned long *bitmap2, unsigned int bits)
217 {
218         unsigned int k;
219         unsigned int nr = BITS_TO_LONGS(bits);
220 
221         for (k = 0; k < nr; k++)
222                 dst[k] = bitmap1[k] ^ bitmap2[k];
223 }
224 EXPORT_SYMBOL(__bitmap_xor);
225 
226 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
227                                 const unsigned long *bitmap2, unsigned int bits)
228 {
229         unsigned int k;
230         unsigned int lim = bits/BITS_PER_LONG;
231         unsigned long result = 0;
232 
233         for (k = 0; k < lim; k++)
234                 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
235         if (bits % BITS_PER_LONG)
236                 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
237                            BITMAP_LAST_WORD_MASK(bits));
238         return result != 0;
239 }
240 EXPORT_SYMBOL(__bitmap_andnot);
241 
242 int __bitmap_intersects(const unsigned long *bitmap1,
243                         const unsigned long *bitmap2, unsigned int bits)
244 {
245         unsigned int k, lim = bits/BITS_PER_LONG;
246         for (k = 0; k < lim; ++k)
247                 if (bitmap1[k] & bitmap2[k])
248                         return 1;
249 
250         if (bits % BITS_PER_LONG)
251                 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
252                         return 1;
253         return 0;
254 }
255 EXPORT_SYMBOL(__bitmap_intersects);
256 
257 int __bitmap_subset(const unsigned long *bitmap1,
258                     const unsigned long *bitmap2, unsigned int bits)
259 {
260         unsigned int k, lim = bits/BITS_PER_LONG;
261         for (k = 0; k < lim; ++k)
262                 if (bitmap1[k] & ~bitmap2[k])
263                         return 0;
264 
265         if (bits % BITS_PER_LONG)
266                 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
267                         return 0;
268         return 1;
269 }
270 EXPORT_SYMBOL(__bitmap_subset);
271 
272 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
273 {
274         unsigned int k, lim = bits/BITS_PER_LONG;
275         int w = 0;
276 
277         for (k = 0; k < lim; k++)
278                 w += hweight_long(bitmap[k]);
279 
280         if (bits % BITS_PER_LONG)
281                 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
282 
283         return w;
284 }
285 EXPORT_SYMBOL(__bitmap_weight);
286 
287 void bitmap_set(unsigned long *map, unsigned int start, int len)
288 {
289         unsigned long *p = map + BIT_WORD(start);
290         const unsigned int size = start + len;
291         int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
292         unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
293 
294         while (len - bits_to_set >= 0) {
295                 *p |= mask_to_set;
296                 len -= bits_to_set;
297                 bits_to_set = BITS_PER_LONG;
298                 mask_to_set = ~0UL;
299                 p++;
300         }
301         if (len) {
302                 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
303                 *p |= mask_to_set;
304         }
305 }
306 EXPORT_SYMBOL(bitmap_set);
307 
308 void bitmap_clear(unsigned long *map, unsigned int start, int len)
309 {
310         unsigned long *p = map + BIT_WORD(start);
311         const unsigned int size = start + len;
312         int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
313         unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
314 
315         while (len - bits_to_clear >= 0) {
316                 *p &= ~mask_to_clear;
317                 len -= bits_to_clear;
318                 bits_to_clear = BITS_PER_LONG;
319                 mask_to_clear = ~0UL;
320                 p++;
321         }
322         if (len) {
323                 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
324                 *p &= ~mask_to_clear;
325         }
326 }
327 EXPORT_SYMBOL(bitmap_clear);
328 
329 /*
330  * bitmap_find_next_zero_area - find a contiguous aligned zero area
331  * @map: The address to base the search on
332  * @size: The bitmap size in bits
333  * @start: The bitnumber to start searching at
334  * @nr: The number of zeroed bits we're looking for
335  * @align_mask: Alignment mask for zero area
336  *
337  * The @align_mask should be one less than a power of 2; the effect is that
338  * the bit offset of all zero areas this function finds is multiples of that
339  * power of 2. A @align_mask of 0 means no alignment is required.
340  */
341 unsigned long bitmap_find_next_zero_area(unsigned long *map,
342                                          unsigned long size,
343                                          unsigned long start,
344                                          unsigned int nr,
345                                          unsigned long align_mask)
346 {
347         unsigned long index, end, i;
348 again:
349         index = find_next_zero_bit(map, size, start);
350 
351         /* Align allocation */
352         index = __ALIGN_MASK(index, align_mask);
353 
354         end = index + nr;
355         if (end > size)
356                 return end;
357         i = find_next_bit(map, end, index);
358         if (i < end) {
359                 start = i + 1;
360                 goto again;
361         }
362         return index;
363 }
364 EXPORT_SYMBOL(bitmap_find_next_zero_area);
365 
366 /*
367  * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
368  * second version by Paul Jackson, third by Joe Korty.
369  */
370 
371 #define CHUNKSZ                         32
372 #define nbits_to_hold_value(val)        fls(val)
373 #define BASEDEC 10              /* fancier cpuset lists input in decimal */
374 
375 /**
376  * bitmap_scnprintf - convert bitmap to an ASCII hex string.
377  * @buf: byte buffer into which string is placed
378  * @buflen: reserved size of @buf, in bytes
379  * @maskp: pointer to bitmap to convert
380  * @nmaskbits: size of bitmap, in bits
381  *
382  * Exactly @nmaskbits bits are displayed.  Hex digits are grouped into
383  * comma-separated sets of eight digits per set.  Returns the number of
384  * characters which were written to *buf, excluding the trailing \0.
385  */
386 int bitmap_scnprintf(char *buf, unsigned int buflen,
387         const unsigned long *maskp, int nmaskbits)
388 {
389         int i, word, bit, len = 0;
390         unsigned long val;
391         const char *sep = "";
392         int chunksz;
393         u32 chunkmask;
394 
395         chunksz = nmaskbits & (CHUNKSZ - 1);
396         if (chunksz == 0)
397                 chunksz = CHUNKSZ;
398 
399         i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
400         for (; i >= 0; i -= CHUNKSZ) {
401                 chunkmask = ((1ULL << chunksz) - 1);
402                 word = i / BITS_PER_LONG;
403                 bit = i % BITS_PER_LONG;
404                 val = (maskp[word] >> bit) & chunkmask;
405                 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
406                         (chunksz+3)/4, val);
407                 chunksz = CHUNKSZ;
408                 sep = ",";
409         }
410         return len;
411 }
412 EXPORT_SYMBOL(bitmap_scnprintf);
413 
414 /**
415  * __bitmap_parse - convert an ASCII hex string into a bitmap.
416  * @buf: pointer to buffer containing string.
417  * @buflen: buffer size in bytes.  If string is smaller than this
418  *    then it must be terminated with a \0.
419  * @is_user: location of buffer, 0 indicates kernel space
420  * @maskp: pointer to bitmap array that will contain result.
421  * @nmaskbits: size of bitmap, in bits.
422  *
423  * Commas group hex digits into chunks.  Each chunk defines exactly 32
424  * bits of the resultant bitmask.  No chunk may specify a value larger
425  * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
426  * then leading 0-bits are prepended.  %-EINVAL is returned for illegal
427  * characters and for grouping errors such as "1,,5", ",44", "," and "".
428  * Leading and trailing whitespace accepted, but not embedded whitespace.
429  */
430 int __bitmap_parse(const char *buf, unsigned int buflen,
431                 int is_user, unsigned long *maskp,
432                 int nmaskbits)
433 {
434         int c, old_c, totaldigits, ndigits, nchunks, nbits;
435         u32 chunk;
436         const char __user __force *ubuf = (const char __user __force *)buf;
437 
438         bitmap_zero(maskp, nmaskbits);
439 
440         nchunks = nbits = totaldigits = c = 0;
441         do {
442                 chunk = ndigits = 0;
443 
444                 /* Get the next chunk of the bitmap */
445                 while (buflen) {
446                         old_c = c;
447                         if (is_user) {
448                                 if (__get_user(c, ubuf++))
449                                         return -EFAULT;
450                         }
451                         else
452                                 c = *buf++;
453                         buflen--;
454                         if (isspace(c))
455                                 continue;
456 
457                         /*
458                          * If the last character was a space and the current
459                          * character isn't '\0', we've got embedded whitespace.
460                          * This is a no-no, so throw an error.
461                          */
462                         if (totaldigits && c && isspace(old_c))
463                                 return -EINVAL;
464 
465                         /* A '\0' or a ',' signal the end of the chunk */
466                         if (c == '\0' || c == ',')
467                                 break;
468 
469                         if (!isxdigit(c))
470                                 return -EINVAL;
471 
472                         /*
473                          * Make sure there are at least 4 free bits in 'chunk'.
474                          * If not, this hexdigit will overflow 'chunk', so
475                          * throw an error.
476                          */
477                         if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
478                                 return -EOVERFLOW;
479 
480                         chunk = (chunk << 4) | hex_to_bin(c);
481                         ndigits++; totaldigits++;
482                 }
483                 if (ndigits == 0)
484                         return -EINVAL;
485                 if (nchunks == 0 && chunk == 0)
486                         continue;
487 
488                 __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
489                 *maskp |= chunk;
490                 nchunks++;
491                 nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
492                 if (nbits > nmaskbits)
493                         return -EOVERFLOW;
494         } while (buflen && c == ',');
495 
496         return 0;
497 }
498 EXPORT_SYMBOL(__bitmap_parse);
499 
500 /**
501  * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
502  *
503  * @ubuf: pointer to user buffer containing string.
504  * @ulen: buffer size in bytes.  If string is smaller than this
505  *    then it must be terminated with a \0.
506  * @maskp: pointer to bitmap array that will contain result.
507  * @nmaskbits: size of bitmap, in bits.
508  *
509  * Wrapper for __bitmap_parse(), providing it with user buffer.
510  *
511  * We cannot have this as an inline function in bitmap.h because it needs
512  * linux/uaccess.h to get the access_ok() declaration and this causes
513  * cyclic dependencies.
514  */
515 int bitmap_parse_user(const char __user *ubuf,
516                         unsigned int ulen, unsigned long *maskp,
517                         int nmaskbits)
518 {
519         if (!access_ok(VERIFY_READ, ubuf, ulen))
520                 return -EFAULT;
521         return __bitmap_parse((const char __force *)ubuf,
522                                 ulen, 1, maskp, nmaskbits);
523 
524 }
525 EXPORT_SYMBOL(bitmap_parse_user);
526 
527 /*
528  * bscnl_emit(buf, buflen, rbot, rtop, bp)
529  *
530  * Helper routine for bitmap_scnlistprintf().  Write decimal number
531  * or range to buf, suppressing output past buf+buflen, with optional
532  * comma-prefix.  Return len of what was written to *buf, excluding the
533  * trailing \0.
534  */
535 static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
536 {
537         if (len > 0)
538                 len += scnprintf(buf + len, buflen - len, ",");
539         if (rbot == rtop)
540                 len += scnprintf(buf + len, buflen - len, "%d", rbot);
541         else
542                 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
543         return len;
544 }
545 
546 /**
547  * bitmap_scnlistprintf - convert bitmap to list format ASCII string
548  * @buf: byte buffer into which string is placed
549  * @buflen: reserved size of @buf, in bytes
550  * @maskp: pointer to bitmap to convert
551  * @nmaskbits: size of bitmap, in bits
552  *
553  * Output format is a comma-separated list of decimal numbers and
554  * ranges.  Consecutively set bits are shown as two hyphen-separated
555  * decimal numbers, the smallest and largest bit numbers set in
556  * the range.  Output format is compatible with the format
557  * accepted as input by bitmap_parselist().
558  *
559  * The return value is the number of characters which were written to *buf
560  * excluding the trailing '\0', as per ISO C99's scnprintf.
561  */
562 int bitmap_scnlistprintf(char *buf, unsigned int buflen,
563         const unsigned long *maskp, int nmaskbits)
564 {
565         int len = 0;
566         /* current bit is 'cur', most recently seen range is [rbot, rtop] */
567         int cur, rbot, rtop;
568 
569         if (buflen == 0)
570                 return 0;
571         buf[0] = 0;
572 
573         rbot = cur = find_first_bit(maskp, nmaskbits);
574         while (cur < nmaskbits) {
575                 rtop = cur;
576                 cur = find_next_bit(maskp, nmaskbits, cur+1);
577                 if (cur >= nmaskbits || cur > rtop + 1) {
578                         len = bscnl_emit(buf, buflen, rbot, rtop, len);
579                         rbot = cur;
580                 }
581         }
582         return len;
583 }
584 EXPORT_SYMBOL(bitmap_scnlistprintf);
585 
586 /**
587  * __bitmap_parselist - convert list format ASCII string to bitmap
588  * @buf: read nul-terminated user string from this buffer
589  * @buflen: buffer size in bytes.  If string is smaller than this
590  *    then it must be terminated with a \0.
591  * @is_user: location of buffer, 0 indicates kernel space
592  * @maskp: write resulting mask here
593  * @nmaskbits: number of bits in mask to be written
594  *
595  * Input format is a comma-separated list of decimal numbers and
596  * ranges.  Consecutively set bits are shown as two hyphen-separated
597  * decimal numbers, the smallest and largest bit numbers set in
598  * the range.
599  *
600  * Returns 0 on success, -errno on invalid input strings.
601  * Error values:
602  *    %-EINVAL: second number in range smaller than first
603  *    %-EINVAL: invalid character in string
604  *    %-ERANGE: bit number specified too large for mask
605  */
606 static int __bitmap_parselist(const char *buf, unsigned int buflen,
607                 int is_user, unsigned long *maskp,
608                 int nmaskbits)
609 {
610         unsigned a, b;
611         int c, old_c, totaldigits;
612         const char __user __force *ubuf = (const char __user __force *)buf;
613         int exp_digit, in_range;
614 
615         totaldigits = c = 0;
616         bitmap_zero(maskp, nmaskbits);
617         do {
618                 exp_digit = 1;
619                 in_range = 0;
620                 a = b = 0;
621 
622                 /* Get the next cpu# or a range of cpu#'s */
623                 while (buflen) {
624                         old_c = c;
625                         if (is_user) {
626                                 if (__get_user(c, ubuf++))
627                                         return -EFAULT;
628                         } else
629                                 c = *buf++;
630                         buflen--;
631                         if (isspace(c))
632                                 continue;
633 
634                         /*
635                          * If the last character was a space and the current
636                          * character isn't '\0', we've got embedded whitespace.
637                          * This is a no-no, so throw an error.
638                          */
639                         if (totaldigits && c && isspace(old_c))
640                                 return -EINVAL;
641 
642                         /* A '\0' or a ',' signal the end of a cpu# or range */
643                         if (c == '\0' || c == ',')
644                                 break;
645 
646                         if (c == '-') {
647                                 if (exp_digit || in_range)
648                                         return -EINVAL;
649                                 b = 0;
650                                 in_range = 1;
651                                 exp_digit = 1;
652                                 continue;
653                         }
654 
655                         if (!isdigit(c))
656                                 return -EINVAL;
657 
658                         b = b * 10 + (c - '');
659                         if (!in_range)
660                                 a = b;
661                         exp_digit = 0;
662                         totaldigits++;
663                 }
664                 if (!(a <= b))
665                         return -EINVAL;
666                 if (b >= nmaskbits)
667                         return -ERANGE;
668                 while (a <= b) {
669                         set_bit(a, maskp);
670                         a++;
671                 }
672         } while (buflen && c == ',');
673         return 0;
674 }
675 
676 int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
677 {
678         char *nl  = strchrnul(bp, '\n');
679         int len = nl - bp;
680 
681         return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
682 }
683 EXPORT_SYMBOL(bitmap_parselist);
684 
685 
686 /**
687  * bitmap_parselist_user()
688  *
689  * @ubuf: pointer to user buffer containing string.
690  * @ulen: buffer size in bytes.  If string is smaller than this
691  *    then it must be terminated with a \0.
692  * @maskp: pointer to bitmap array that will contain result.
693  * @nmaskbits: size of bitmap, in bits.
694  *
695  * Wrapper for bitmap_parselist(), providing it with user buffer.
696  *
697  * We cannot have this as an inline function in bitmap.h because it needs
698  * linux/uaccess.h to get the access_ok() declaration and this causes
699  * cyclic dependencies.
700  */
701 int bitmap_parselist_user(const char __user *ubuf,
702                         unsigned int ulen, unsigned long *maskp,
703                         int nmaskbits)
704 {
705         if (!access_ok(VERIFY_READ, ubuf, ulen))
706                 return -EFAULT;
707         return __bitmap_parselist((const char __force *)ubuf,
708                                         ulen, 1, maskp, nmaskbits);
709 }
710 EXPORT_SYMBOL(bitmap_parselist_user);
711 
712 
713 /**
714  * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
715  *      @buf: pointer to a bitmap
716  *      @pos: a bit position in @buf (0 <= @pos < @bits)
717  *      @bits: number of valid bit positions in @buf
718  *
719  * Map the bit at position @pos in @buf (of length @bits) to the
720  * ordinal of which set bit it is.  If it is not set or if @pos
721  * is not a valid bit position, map to -1.
722  *
723  * If for example, just bits 4 through 7 are set in @buf, then @pos
724  * values 4 through 7 will get mapped to 0 through 3, respectively,
725  * and other @pos values will get mapped to -1.  When @pos value 7
726  * gets mapped to (returns) @ord value 3 in this example, that means
727  * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
728  *
729  * The bit positions 0 through @bits are valid positions in @buf.
730  */
731 static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
732 {
733         int i, ord;
734 
735         if (pos < 0 || pos >= bits || !test_bit(pos, buf))
736                 return -1;
737 
738         i = find_first_bit(buf, bits);
739         ord = 0;
740         while (i < pos) {
741                 i = find_next_bit(buf, bits, i + 1);
742                 ord++;
743         }
744         BUG_ON(i != pos);
745 
746         return ord;
747 }
748 
749 /**
750  * bitmap_ord_to_pos - find position of n-th set bit in bitmap
751  *      @buf: pointer to bitmap
752  *      @ord: ordinal bit position (n-th set bit, n >= 0)
753  *      @bits: number of valid bit positions in @buf
754  *
755  * Map the ordinal offset of bit @ord in @buf to its position in @buf.
756  * Value of @ord should be in range 0 <= @ord < weight(buf), else
757  * results are undefined.
758  *
759  * If for example, just bits 4 through 7 are set in @buf, then @ord
760  * values 0 through 3 will get mapped to 4 through 7, respectively,
761  * and all other @ord values return undefined values.  When @ord value 3
762  * gets mapped to (returns) @pos value 7 in this example, that means
763  * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
764  *
765  * The bit positions 0 through @bits are valid positions in @buf.
766  */
767 int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
768 {
769         int pos = 0;
770 
771         if (ord >= 0 && ord < bits) {
772                 int i;
773 
774                 for (i = find_first_bit(buf, bits);
775                      i < bits && ord > 0;
776                      i = find_next_bit(buf, bits, i + 1))
777                         ord--;
778                 if (i < bits && ord == 0)
779                         pos = i;
780         }
781 
782         return pos;
783 }
784 
785 /**
786  * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
787  *      @dst: remapped result
788  *      @src: subset to be remapped
789  *      @old: defines domain of map
790  *      @new: defines range of map
791  *      @bits: number of bits in each of these bitmaps
792  *
793  * Let @old and @new define a mapping of bit positions, such that
794  * whatever position is held by the n-th set bit in @old is mapped
795  * to the n-th set bit in @new.  In the more general case, allowing
796  * for the possibility that the weight 'w' of @new is less than the
797  * weight of @old, map the position of the n-th set bit in @old to
798  * the position of the m-th set bit in @new, where m == n % w.
799  *
800  * If either of the @old and @new bitmaps are empty, or if @src and
801  * @dst point to the same location, then this routine copies @src
802  * to @dst.
803  *
804  * The positions of unset bits in @old are mapped to themselves
805  * (the identify map).
806  *
807  * Apply the above specified mapping to @src, placing the result in
808  * @dst, clearing any bits previously set in @dst.
809  *
810  * For example, lets say that @old has bits 4 through 7 set, and
811  * @new has bits 12 through 15 set.  This defines the mapping of bit
812  * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
813  * bit positions unchanged.  So if say @src comes into this routine
814  * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
815  * 13 and 15 set.
816  */
817 void bitmap_remap(unsigned long *dst, const unsigned long *src,
818                 const unsigned long *old, const unsigned long *new,
819                 int bits)
820 {
821         int oldbit, w;
822 
823         if (dst == src)         /* following doesn't handle inplace remaps */
824                 return;
825         bitmap_zero(dst, bits);
826 
827         w = bitmap_weight(new, bits);
828         for_each_set_bit(oldbit, src, bits) {
829                 int n = bitmap_pos_to_ord(old, oldbit, bits);
830 
831                 if (n < 0 || w == 0)
832                         set_bit(oldbit, dst);   /* identity map */
833                 else
834                         set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
835         }
836 }
837 EXPORT_SYMBOL(bitmap_remap);
838 
839 /**
840  * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
841  *      @oldbit: bit position to be mapped
842  *      @old: defines domain of map
843  *      @new: defines range of map
844  *      @bits: number of bits in each of these bitmaps
845  *
846  * Let @old and @new define a mapping of bit positions, such that
847  * whatever position is held by the n-th set bit in @old is mapped
848  * to the n-th set bit in @new.  In the more general case, allowing
849  * for the possibility that the weight 'w' of @new is less than the
850  * weight of @old, map the position of the n-th set bit in @old to
851  * the position of the m-th set bit in @new, where m == n % w.
852  *
853  * The positions of unset bits in @old are mapped to themselves
854  * (the identify map).
855  *
856  * Apply the above specified mapping to bit position @oldbit, returning
857  * the new bit position.
858  *
859  * For example, lets say that @old has bits 4 through 7 set, and
860  * @new has bits 12 through 15 set.  This defines the mapping of bit
861  * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
862  * bit positions unchanged.  So if say @oldbit is 5, then this routine
863  * returns 13.
864  */
865 int bitmap_bitremap(int oldbit, const unsigned long *old,
866                                 const unsigned long *new, int bits)
867 {
868         int w = bitmap_weight(new, bits);
869         int n = bitmap_pos_to_ord(old, oldbit, bits);
870         if (n < 0 || w == 0)
871                 return oldbit;
872         else
873                 return bitmap_ord_to_pos(new, n % w, bits);
874 }
875 EXPORT_SYMBOL(bitmap_bitremap);
876 
877 /**
878  * bitmap_onto - translate one bitmap relative to another
879  *      @dst: resulting translated bitmap
880  *      @orig: original untranslated bitmap
881  *      @relmap: bitmap relative to which translated
882  *      @bits: number of bits in each of these bitmaps
883  *
884  * Set the n-th bit of @dst iff there exists some m such that the
885  * n-th bit of @relmap is set, the m-th bit of @orig is set, and
886  * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
887  * (If you understood the previous sentence the first time your
888  * read it, you're overqualified for your current job.)
889  *
890  * In other words, @orig is mapped onto (surjectively) @dst,
891  * using the map { <n, m> | the n-th bit of @relmap is the
892  * m-th set bit of @relmap }.
893  *
894  * Any set bits in @orig above bit number W, where W is the
895  * weight of (number of set bits in) @relmap are mapped nowhere.
896  * In particular, if for all bits m set in @orig, m >= W, then
897  * @dst will end up empty.  In situations where the possibility
898  * of such an empty result is not desired, one way to avoid it is
899  * to use the bitmap_fold() operator, below, to first fold the
900  * @orig bitmap over itself so that all its set bits x are in the
901  * range 0 <= x < W.  The bitmap_fold() operator does this by
902  * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
903  *
904  * Example [1] for bitmap_onto():
905  *  Let's say @relmap has bits 30-39 set, and @orig has bits
906  *  1, 3, 5, 7, 9 and 11 set.  Then on return from this routine,
907  *  @dst will have bits 31, 33, 35, 37 and 39 set.
908  *
909  *  When bit 0 is set in @orig, it means turn on the bit in
910  *  @dst corresponding to whatever is the first bit (if any)
911  *  that is turned on in @relmap.  Since bit 0 was off in the
912  *  above example, we leave off that bit (bit 30) in @dst.
913  *
914  *  When bit 1 is set in @orig (as in the above example), it
915  *  means turn on the bit in @dst corresponding to whatever
916  *  is the second bit that is turned on in @relmap.  The second
917  *  bit in @relmap that was turned on in the above example was
918  *  bit 31, so we turned on bit 31 in @dst.
919  *
920  *  Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
921  *  because they were the 4th, 6th, 8th and 10th set bits
922  *  set in @relmap, and the 4th, 6th, 8th and 10th bits of
923  *  @orig (i.e. bits 3, 5, 7 and 9) were also set.
924  *
925  *  When bit 11 is set in @orig, it means turn on the bit in
926  *  @dst corresponding to whatever is the twelfth bit that is
927  *  turned on in @relmap.  In the above example, there were
928  *  only ten bits turned on in @relmap (30..39), so that bit
929  *  11 was set in @orig had no affect on @dst.
930  *
931  * Example [2] for bitmap_fold() + bitmap_onto():
932  *  Let's say @relmap has these ten bits set:
933  *              40 41 42 43 45 48 53 61 74 95
934  *  (for the curious, that's 40 plus the first ten terms of the
935  *  Fibonacci sequence.)
936  *
937  *  Further lets say we use the following code, invoking
938  *  bitmap_fold() then bitmap_onto, as suggested above to
939  *  avoid the possibility of an empty @dst result:
940  *
941  *      unsigned long *tmp;     // a temporary bitmap's bits
942  *
943  *      bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
944  *      bitmap_onto(dst, tmp, relmap, bits);
945  *
946  *  Then this table shows what various values of @dst would be, for
947  *  various @orig's.  I list the zero-based positions of each set bit.
948  *  The tmp column shows the intermediate result, as computed by
949  *  using bitmap_fold() to fold the @orig bitmap modulo ten
950  *  (the weight of @relmap).
951  *
952  *      @orig           tmp            @dst
953  *      0                0             40
954  *      1                1             41
955  *      9                9             95
956  *      10               0             40 (*)
957  *      1 3 5 7          1 3 5 7       41 43 48 61
958  *      0 1 2 3 4        0 1 2 3 4     40 41 42 43 45
959  *      0 9 18 27        0 9 8 7       40 61 74 95
960  *      0 10 20 30       0             40
961  *      0 11 22 33       0 1 2 3       40 41 42 43
962  *      0 12 24 36       0 2 4 6       40 42 45 53
963  *      78 102 211       1 2 8         41 42 74 (*)
964  *
965  * (*) For these marked lines, if we hadn't first done bitmap_fold()
966  *     into tmp, then the @dst result would have been empty.
967  *
968  * If either of @orig or @relmap is empty (no set bits), then @dst
969  * will be returned empty.
970  *
971  * If (as explained above) the only set bits in @orig are in positions
972  * m where m >= W, (where W is the weight of @relmap) then @dst will
973  * once again be returned empty.
974  *
975  * All bits in @dst not set by the above rule are cleared.
976  */
977 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
978                         const unsigned long *relmap, int bits)
979 {
980         int n, m;               /* same meaning as in above comment */
981 
982         if (dst == orig)        /* following doesn't handle inplace mappings */
983                 return;
984         bitmap_zero(dst, bits);
985 
986         /*
987          * The following code is a more efficient, but less
988          * obvious, equivalent to the loop:
989          *      for (m = 0; m < bitmap_weight(relmap, bits); m++) {
990          *              n = bitmap_ord_to_pos(orig, m, bits);
991          *              if (test_bit(m, orig))
992          *                      set_bit(n, dst);
993          *      }
994          */
995 
996         m = 0;
997         for_each_set_bit(n, relmap, bits) {
998                 /* m == bitmap_pos_to_ord(relmap, n, bits) */
999                 if (test_bit(m, orig))
1000                         set_bit(n, dst);
1001                 m++;
1002         }
1003 }
1004 EXPORT_SYMBOL(bitmap_onto);
1005 
1006 /**
1007  * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1008  *      @dst: resulting smaller bitmap
1009  *      @orig: original larger bitmap
1010  *      @sz: specified size
1011  *      @bits: number of bits in each of these bitmaps
1012  *
1013  * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1014  * Clear all other bits in @dst.  See further the comment and
1015  * Example [2] for bitmap_onto() for why and how to use this.
1016  */
1017 void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1018                         int sz, int bits)
1019 {
1020         int oldbit;
1021 
1022         if (dst == orig)        /* following doesn't handle inplace mappings */
1023                 return;
1024         bitmap_zero(dst, bits);
1025 
1026         for_each_set_bit(oldbit, orig, bits)
1027                 set_bit(oldbit % sz, dst);
1028 }
1029 EXPORT_SYMBOL(bitmap_fold);
1030 
1031 /*
1032  * Common code for bitmap_*_region() routines.
1033  *      bitmap: array of unsigned longs corresponding to the bitmap
1034  *      pos: the beginning of the region
1035  *      order: region size (log base 2 of number of bits)
1036  *      reg_op: operation(s) to perform on that region of bitmap
1037  *
1038  * Can set, verify and/or release a region of bits in a bitmap,
1039  * depending on which combination of REG_OP_* flag bits is set.
1040  *
1041  * A region of a bitmap is a sequence of bits in the bitmap, of
1042  * some size '1 << order' (a power of two), aligned to that same
1043  * '1 << order' power of two.
1044  *
1045  * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1046  * Returns 0 in all other cases and reg_ops.
1047  */
1048 
1049 enum {
1050         REG_OP_ISFREE,          /* true if region is all zero bits */
1051         REG_OP_ALLOC,           /* set all bits in region */
1052         REG_OP_RELEASE,         /* clear all bits in region */
1053 };
1054 
1055 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
1056 {
1057         int nbits_reg;          /* number of bits in region */
1058         int index;              /* index first long of region in bitmap */
1059         int offset;             /* bit offset region in bitmap[index] */
1060         int nlongs_reg;         /* num longs spanned by region in bitmap */
1061         int nbitsinlong;        /* num bits of region in each spanned long */
1062         unsigned long mask;     /* bitmask for one long of region */
1063         int i;                  /* scans bitmap by longs */
1064         int ret = 0;            /* return value */
1065 
1066         /*
1067          * Either nlongs_reg == 1 (for small orders that fit in one long)
1068          * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1069          */
1070         nbits_reg = 1 << order;
1071         index = pos / BITS_PER_LONG;
1072         offset = pos - (index * BITS_PER_LONG);
1073         nlongs_reg = BITS_TO_LONGS(nbits_reg);
1074         nbitsinlong = min(nbits_reg,  BITS_PER_LONG);
1075 
1076         /*
1077          * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1078          * overflows if nbitsinlong == BITS_PER_LONG.
1079          */
1080         mask = (1UL << (nbitsinlong - 1));
1081         mask += mask - 1;
1082         mask <<= offset;
1083 
1084         switch (reg_op) {
1085         case REG_OP_ISFREE:
1086                 for (i = 0; i < nlongs_reg; i++) {
1087                         if (bitmap[index + i] & mask)
1088                                 goto done;
1089                 }
1090                 ret = 1;        /* all bits in region free (zero) */
1091                 break;
1092 
1093         case REG_OP_ALLOC:
1094                 for (i = 0; i < nlongs_reg; i++)
1095                         bitmap[index + i] |= mask;
1096                 break;
1097 
1098         case REG_OP_RELEASE:
1099                 for (i = 0; i < nlongs_reg; i++)
1100                         bitmap[index + i] &= ~mask;
1101                 break;
1102         }
1103 done:
1104         return ret;
1105 }
1106 
1107 /**
1108  * bitmap_find_free_region - find a contiguous aligned mem region
1109  *      @bitmap: array of unsigned longs corresponding to the bitmap
1110  *      @bits: number of bits in the bitmap
1111  *      @order: region size (log base 2 of number of bits) to find
1112  *
1113  * Find a region of free (zero) bits in a @bitmap of @bits bits and
1114  * allocate them (set them to one).  Only consider regions of length
1115  * a power (@order) of two, aligned to that power of two, which
1116  * makes the search algorithm much faster.
1117  *
1118  * Return the bit offset in bitmap of the allocated region,
1119  * or -errno on failure.
1120  */
1121 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1122 {
1123         unsigned int pos, end;          /* scans bitmap by regions of size order */
1124 
1125         for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1126                 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1127                         continue;
1128                 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1129                 return pos;
1130         }
1131         return -ENOMEM;
1132 }
1133 EXPORT_SYMBOL(bitmap_find_free_region);
1134 
1135 /**
1136  * bitmap_release_region - release allocated bitmap region
1137  *      @bitmap: array of unsigned longs corresponding to the bitmap
1138  *      @pos: beginning of bit region to release
1139  *      @order: region size (log base 2 of number of bits) to release
1140  *
1141  * This is the complement to __bitmap_find_free_region() and releases
1142  * the found region (by clearing it in the bitmap).
1143  *
1144  * No return value.
1145  */
1146 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1147 {
1148         __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1149 }
1150 EXPORT_SYMBOL(bitmap_release_region);
1151 
1152 /**
1153  * bitmap_allocate_region - allocate bitmap region
1154  *      @bitmap: array of unsigned longs corresponding to the bitmap
1155  *      @pos: beginning of bit region to allocate
1156  *      @order: region size (log base 2 of number of bits) to allocate
1157  *
1158  * Allocate (set bits in) a specified region of a bitmap.
1159  *
1160  * Return 0 on success, or %-EBUSY if specified region wasn't
1161  * free (not all bits were zero).
1162  */
1163 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1164 {
1165         if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1166                 return -EBUSY;
1167         return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1168 }
1169 EXPORT_SYMBOL(bitmap_allocate_region);
1170 
1171 /**
1172  * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1173  * @dst:   destination buffer
1174  * @src:   bitmap to copy
1175  * @nbits: number of bits in the bitmap
1176  *
1177  * Require nbits % BITS_PER_LONG == 0.
1178  */
1179 void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1180 {
1181         unsigned long *d = dst;
1182         int i;
1183 
1184         for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1185                 if (BITS_PER_LONG == 64)
1186                         d[i] = cpu_to_le64(src[i]);
1187                 else
1188                         d[i] = cpu_to_le32(src[i]);
1189         }
1190 }
1191 EXPORT_SYMBOL(bitmap_copy_le);
1192 

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