Version:  2.0.40 2.2.26 2.4.37 3.1 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

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

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