1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * lib/bitmap.c
4 * Helper functions for bitmap.h.
5 */
6
7 #include <linux/bitmap.h>
8 #include <linux/bitops.h>
9 #include <linux/bug.h>
10 #include <linux/ctype.h>
11 #include <linux/device.h>
12 #include <linux/errno.h>
13 #include <linux/export.h>
14 #include <linux/kernel.h>
15 #include <linux/mm.h>
16 #include <linux/slab.h>
17 #include <linux/string.h>
18 #include <linux/thread_info.h>
19 #include <linux/uaccess.h>
20
21 #include <asm/page.h>
22
23 #include "kstrtox.h"
24
25 /**
26 * DOC: bitmap introduction
27 *
28 * bitmaps provide an array of bits, implemented using an
29 * array of unsigned longs. The number of valid bits in a
30 * given bitmap does _not_ need to be an exact multiple of
31 * BITS_PER_LONG.
32 *
33 * The possible unused bits in the last, partially used word
34 * of a bitmap are 'don't care'. The implementation makes
35 * no particular effort to keep them zero. It ensures that
36 * their value will not affect the results of any operation.
37 * The bitmap operations that return Boolean (bitmap_empty,
38 * for example) or scalar (bitmap_weight, for example) results
39 * carefully filter out these unused bits from impacting their
40 * results.
41 *
42 * The byte ordering of bitmaps is more natural on little
43 * endian architectures. See the big-endian headers
44 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
45 * for the best explanations of this ordering.
46 */
47
__bitmap_equal(const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)48 bool __bitmap_equal(const unsigned long *bitmap1,
49 const unsigned long *bitmap2, unsigned int bits)
50 {
51 unsigned int k, lim = bits/BITS_PER_LONG;
52 for (k = 0; k < lim; ++k)
53 if (bitmap1[k] != bitmap2[k])
54 return false;
55
56 if (bits % BITS_PER_LONG)
57 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
58 return false;
59
60 return true;
61 }
62 EXPORT_SYMBOL(__bitmap_equal);
63
__bitmap_or_equal(const unsigned long * bitmap1,const unsigned long * bitmap2,const unsigned long * bitmap3,unsigned int bits)64 bool __bitmap_or_equal(const unsigned long *bitmap1,
65 const unsigned long *bitmap2,
66 const unsigned long *bitmap3,
67 unsigned int bits)
68 {
69 unsigned int k, lim = bits / BITS_PER_LONG;
70 unsigned long tmp;
71
72 for (k = 0; k < lim; ++k) {
73 if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
74 return false;
75 }
76
77 if (!(bits % BITS_PER_LONG))
78 return true;
79
80 tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
81 return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
82 }
83
__bitmap_complement(unsigned long * dst,const unsigned long * src,unsigned int bits)84 void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
85 {
86 unsigned int k, lim = BITS_TO_LONGS(bits);
87 for (k = 0; k < lim; ++k)
88 dst[k] = ~src[k];
89 }
90 EXPORT_SYMBOL(__bitmap_complement);
91
92 /**
93 * __bitmap_shift_right - logical right shift of the bits in a bitmap
94 * @dst : destination bitmap
95 * @src : source bitmap
96 * @shift : shift by this many bits
97 * @nbits : bitmap size, in bits
98 *
99 * Shifting right (dividing) means moving bits in the MS -> LS bit
100 * direction. Zeros are fed into the vacated MS positions and the
101 * LS bits shifted off the bottom are lost.
102 */
__bitmap_shift_right(unsigned long * dst,const unsigned long * src,unsigned shift,unsigned nbits)103 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
104 unsigned shift, unsigned nbits)
105 {
106 unsigned k, lim = BITS_TO_LONGS(nbits);
107 unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
108 unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
109 for (k = 0; off + k < lim; ++k) {
110 unsigned long upper, lower;
111
112 /*
113 * If shift is not word aligned, take lower rem bits of
114 * word above and make them the top rem bits of result.
115 */
116 if (!rem || off + k + 1 >= lim)
117 upper = 0;
118 else {
119 upper = src[off + k + 1];
120 if (off + k + 1 == lim - 1)
121 upper &= mask;
122 upper <<= (BITS_PER_LONG - rem);
123 }
124 lower = src[off + k];
125 if (off + k == lim - 1)
126 lower &= mask;
127 lower >>= rem;
128 dst[k] = lower | upper;
129 }
130 if (off)
131 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
132 }
133 EXPORT_SYMBOL(__bitmap_shift_right);
134
135
136 /**
137 * __bitmap_shift_left - logical left shift of the bits in a bitmap
138 * @dst : destination bitmap
139 * @src : source bitmap
140 * @shift : shift by this many bits
141 * @nbits : bitmap size, in bits
142 *
143 * Shifting left (multiplying) means moving bits in the LS -> MS
144 * direction. Zeros are fed into the vacated LS bit positions
145 * and those MS bits shifted off the top are lost.
146 */
147
__bitmap_shift_left(unsigned long * dst,const unsigned long * src,unsigned int shift,unsigned int nbits)148 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
149 unsigned int shift, unsigned int nbits)
150 {
151 int k;
152 unsigned int lim = BITS_TO_LONGS(nbits);
153 unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
154 for (k = lim - off - 1; k >= 0; --k) {
155 unsigned long upper, lower;
156
157 /*
158 * If shift is not word aligned, take upper rem bits of
159 * word below and make them the bottom rem bits of result.
160 */
161 if (rem && k > 0)
162 lower = src[k - 1] >> (BITS_PER_LONG - rem);
163 else
164 lower = 0;
165 upper = src[k] << rem;
166 dst[k + off] = lower | upper;
167 }
168 if (off)
169 memset(dst, 0, off*sizeof(unsigned long));
170 }
171 EXPORT_SYMBOL(__bitmap_shift_left);
172
173 /**
174 * bitmap_cut() - remove bit region from bitmap and right shift remaining bits
175 * @dst: destination bitmap, might overlap with src
176 * @src: source bitmap
177 * @first: start bit of region to be removed
178 * @cut: number of bits to remove
179 * @nbits: bitmap size, in bits
180 *
181 * Set the n-th bit of @dst iff the n-th bit of @src is set and
182 * n is less than @first, or the m-th bit of @src is set for any
183 * m such that @first <= n < nbits, and m = n + @cut.
184 *
185 * In pictures, example for a big-endian 32-bit architecture:
186 *
187 * The @src bitmap is::
188 *
189 * 31 63
190 * | |
191 * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101
192 * | | | |
193 * 16 14 0 32
194 *
195 * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is::
196 *
197 * 31 63
198 * | |
199 * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010
200 * | | |
201 * 14 (bit 17 0 32
202 * from @src)
203 *
204 * Note that @dst and @src might overlap partially or entirely.
205 *
206 * This is implemented in the obvious way, with a shift and carry
207 * step for each moved bit. Optimisation is left as an exercise
208 * for the compiler.
209 */
bitmap_cut(unsigned long * dst,const unsigned long * src,unsigned int first,unsigned int cut,unsigned int nbits)210 void bitmap_cut(unsigned long *dst, const unsigned long *src,
211 unsigned int first, unsigned int cut, unsigned int nbits)
212 {
213 unsigned int len = BITS_TO_LONGS(nbits);
214 unsigned long keep = 0, carry;
215 int i;
216
217 if (first % BITS_PER_LONG) {
218 keep = src[first / BITS_PER_LONG] &
219 (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG));
220 }
221
222 memmove(dst, src, len * sizeof(*dst));
223
224 while (cut--) {
225 for (i = first / BITS_PER_LONG; i < len; i++) {
226 if (i < len - 1)
227 carry = dst[i + 1] & 1UL;
228 else
229 carry = 0;
230
231 dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1));
232 }
233 }
234
235 dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG);
236 dst[first / BITS_PER_LONG] |= keep;
237 }
238 EXPORT_SYMBOL(bitmap_cut);
239
__bitmap_and(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)240 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
241 const unsigned long *bitmap2, unsigned int bits)
242 {
243 unsigned int k;
244 unsigned int lim = bits/BITS_PER_LONG;
245 unsigned long result = 0;
246
247 for (k = 0; k < lim; k++)
248 result |= (dst[k] = bitmap1[k] & bitmap2[k]);
249 if (bits % BITS_PER_LONG)
250 result |= (dst[k] = bitmap1[k] & bitmap2[k] &
251 BITMAP_LAST_WORD_MASK(bits));
252 return result != 0;
253 }
254 EXPORT_SYMBOL(__bitmap_and);
255
__bitmap_or(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)256 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
257 const unsigned long *bitmap2, unsigned int bits)
258 {
259 unsigned int k;
260 unsigned int nr = BITS_TO_LONGS(bits);
261
262 for (k = 0; k < nr; k++)
263 dst[k] = bitmap1[k] | bitmap2[k];
264 }
265 EXPORT_SYMBOL(__bitmap_or);
266
__bitmap_xor(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)267 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
268 const unsigned long *bitmap2, unsigned int bits)
269 {
270 unsigned int k;
271 unsigned int nr = BITS_TO_LONGS(bits);
272
273 for (k = 0; k < nr; k++)
274 dst[k] = bitmap1[k] ^ bitmap2[k];
275 }
276 EXPORT_SYMBOL(__bitmap_xor);
277
__bitmap_andnot(unsigned long * dst,const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)278 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
279 const unsigned long *bitmap2, unsigned int bits)
280 {
281 unsigned int k;
282 unsigned int lim = bits/BITS_PER_LONG;
283 unsigned long result = 0;
284
285 for (k = 0; k < lim; k++)
286 result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
287 if (bits % BITS_PER_LONG)
288 result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
289 BITMAP_LAST_WORD_MASK(bits));
290 return result != 0;
291 }
292 EXPORT_SYMBOL(__bitmap_andnot);
293
__bitmap_replace(unsigned long * dst,const unsigned long * old,const unsigned long * new,const unsigned long * mask,unsigned int nbits)294 void __bitmap_replace(unsigned long *dst,
295 const unsigned long *old, const unsigned long *new,
296 const unsigned long *mask, unsigned int nbits)
297 {
298 unsigned int k;
299 unsigned int nr = BITS_TO_LONGS(nbits);
300
301 for (k = 0; k < nr; k++)
302 dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]);
303 }
304 EXPORT_SYMBOL(__bitmap_replace);
305
__bitmap_intersects(const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)306 bool __bitmap_intersects(const unsigned long *bitmap1,
307 const unsigned long *bitmap2, unsigned int bits)
308 {
309 unsigned int k, lim = bits/BITS_PER_LONG;
310 for (k = 0; k < lim; ++k)
311 if (bitmap1[k] & bitmap2[k])
312 return true;
313
314 if (bits % BITS_PER_LONG)
315 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
316 return true;
317 return false;
318 }
319 EXPORT_SYMBOL(__bitmap_intersects);
320
__bitmap_subset(const unsigned long * bitmap1,const unsigned long * bitmap2,unsigned int bits)321 bool __bitmap_subset(const unsigned long *bitmap1,
322 const unsigned long *bitmap2, unsigned int bits)
323 {
324 unsigned int k, lim = bits/BITS_PER_LONG;
325 for (k = 0; k < lim; ++k)
326 if (bitmap1[k] & ~bitmap2[k])
327 return false;
328
329 if (bits % BITS_PER_LONG)
330 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
331 return false;
332 return true;
333 }
334 EXPORT_SYMBOL(__bitmap_subset);
335
__bitmap_weight(const unsigned long * bitmap,unsigned int bits)336 int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
337 {
338 unsigned int k, lim = bits/BITS_PER_LONG;
339 int w = 0;
340
341 for (k = 0; k < lim; k++)
342 w += hweight_long(bitmap[k]);
343
344 if (bits % BITS_PER_LONG)
345 w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
346
347 return w;
348 }
349 EXPORT_SYMBOL(__bitmap_weight);
350
__bitmap_set(unsigned long * map,unsigned int start,int len)351 void __bitmap_set(unsigned long *map, unsigned int start, int len)
352 {
353 unsigned long *p = map + BIT_WORD(start);
354 const unsigned int size = start + len;
355 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
356 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
357
358 while (len - bits_to_set >= 0) {
359 *p |= mask_to_set;
360 len -= bits_to_set;
361 bits_to_set = BITS_PER_LONG;
362 mask_to_set = ~0UL;
363 p++;
364 }
365 if (len) {
366 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
367 *p |= mask_to_set;
368 }
369 }
370 EXPORT_SYMBOL(__bitmap_set);
371
__bitmap_clear(unsigned long * map,unsigned int start,int len)372 void __bitmap_clear(unsigned long *map, unsigned int start, int len)
373 {
374 unsigned long *p = map + BIT_WORD(start);
375 const unsigned int size = start + len;
376 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
377 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
378
379 while (len - bits_to_clear >= 0) {
380 *p &= ~mask_to_clear;
381 len -= bits_to_clear;
382 bits_to_clear = BITS_PER_LONG;
383 mask_to_clear = ~0UL;
384 p++;
385 }
386 if (len) {
387 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
388 *p &= ~mask_to_clear;
389 }
390 }
391 EXPORT_SYMBOL(__bitmap_clear);
392
393 /**
394 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
395 * @map: The address to base the search on
396 * @size: The bitmap size in bits
397 * @start: The bitnumber to start searching at
398 * @nr: The number of zeroed bits we're looking for
399 * @align_mask: Alignment mask for zero area
400 * @align_offset: Alignment offset for zero area.
401 *
402 * The @align_mask should be one less than a power of 2; the effect is that
403 * the bit offset of all zero areas this function finds plus @align_offset
404 * is multiple of that power of 2.
405 */
bitmap_find_next_zero_area_off(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,unsigned long align_mask,unsigned long align_offset)406 unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
407 unsigned long size,
408 unsigned long start,
409 unsigned int nr,
410 unsigned long align_mask,
411 unsigned long align_offset)
412 {
413 unsigned long index, end, i;
414 again:
415 index = find_next_zero_bit(map, size, start);
416
417 /* Align allocation */
418 index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
419
420 end = index + nr;
421 if (end > size)
422 return end;
423 i = find_next_bit(map, end, index);
424 if (i < end) {
425 start = i + 1;
426 goto again;
427 }
428 return index;
429 }
430 EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
431
432 /*
433 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
434 * second version by Paul Jackson, third by Joe Korty.
435 */
436
437 /**
438 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
439 *
440 * @ubuf: pointer to user buffer containing string.
441 * @ulen: buffer size in bytes. If string is smaller than this
442 * then it must be terminated with a \0.
443 * @maskp: pointer to bitmap array that will contain result.
444 * @nmaskbits: size of bitmap, in bits.
445 */
bitmap_parse_user(const char __user * ubuf,unsigned int ulen,unsigned long * maskp,int nmaskbits)446 int bitmap_parse_user(const char __user *ubuf,
447 unsigned int ulen, unsigned long *maskp,
448 int nmaskbits)
449 {
450 char *buf;
451 int ret;
452
453 buf = memdup_user_nul(ubuf, ulen);
454 if (IS_ERR(buf))
455 return PTR_ERR(buf);
456
457 ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits);
458
459 kfree(buf);
460 return ret;
461 }
462 EXPORT_SYMBOL(bitmap_parse_user);
463
464 /**
465 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
466 * @list: indicates whether the bitmap must be list
467 * @buf: page aligned buffer into which string is placed
468 * @maskp: pointer to bitmap to convert
469 * @nmaskbits: size of bitmap, in bits
470 *
471 * Output format is a comma-separated list of decimal numbers and
472 * ranges if list is specified or hex digits grouped into comma-separated
473 * sets of 8 digits/set. Returns the number of characters written to buf.
474 *
475 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
476 * area and that sufficient storage remains at @buf to accommodate the
477 * bitmap_print_to_pagebuf() output. Returns the number of characters
478 * actually printed to @buf, excluding terminating '\0'.
479 */
bitmap_print_to_pagebuf(bool list,char * buf,const unsigned long * maskp,int nmaskbits)480 int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
481 int nmaskbits)
482 {
483 ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
484
485 return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
486 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
487 }
488 EXPORT_SYMBOL(bitmap_print_to_pagebuf);
489
490 /**
491 * bitmap_print_to_buf - convert bitmap to list or hex format ASCII string
492 * @list: indicates whether the bitmap must be list
493 * true: print in decimal list format
494 * false: print in hexadecimal bitmask format
495 * @buf: buffer into which string is placed
496 * @maskp: pointer to bitmap to convert
497 * @nmaskbits: size of bitmap, in bits
498 * @off: in the string from which we are copying, We copy to @buf
499 * @count: the maximum number of bytes to print
500 */
bitmap_print_to_buf(bool list,char * buf,const unsigned long * maskp,int nmaskbits,loff_t off,size_t count)501 static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
502 int nmaskbits, loff_t off, size_t count)
503 {
504 const char *fmt = list ? "%*pbl\n" : "%*pb\n";
505 ssize_t size;
506 void *data;
507
508 data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp);
509 if (!data)
510 return -ENOMEM;
511
512 size = memory_read_from_buffer(buf, count, &off, data, strlen(data) + 1);
513 kfree(data);
514
515 return size;
516 }
517
518 /**
519 * bitmap_print_bitmask_to_buf - convert bitmap to hex bitmask format ASCII string
520 * @buf: buffer into which string is placed
521 * @maskp: pointer to bitmap to convert
522 * @nmaskbits: size of bitmap, in bits
523 * @off: in the string from which we are copying, We copy to @buf
524 * @count: the maximum number of bytes to print
525 *
526 * The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper
527 * cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
528 * bitmask and decimal list to userspace by sysfs ABI.
529 * Drivers might be using a normal attribute for this kind of ABIs. A
530 * normal attribute typically has show entry as below::
531 *
532 * static ssize_t example_attribute_show(struct device *dev,
533 * struct device_attribute *attr, char *buf)
534 * {
535 * ...
536 * return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max);
537 * }
538 *
539 * show entry of attribute has no offset and count parameters and this
540 * means the file is limited to one page only.
541 * bitmap_print_to_pagebuf() API works terribly well for this kind of
542 * normal attribute with buf parameter and without offset, count::
543 *
544 * bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
545 * int nmaskbits)
546 * {
547 * }
548 *
549 * The problem is once we have a large bitmap, we have a chance to get a
550 * bitmask or list more than one page. Especially for list, it could be
551 * as complex as 0,3,5,7,9,... We have no simple way to know it exact size.
552 * It turns out bin_attribute is a way to break this limit. bin_attribute
553 * has show entry as below::
554 *
555 * static ssize_t
556 * example_bin_attribute_show(struct file *filp, struct kobject *kobj,
557 * struct bin_attribute *attr, char *buf,
558 * loff_t offset, size_t count)
559 * {
560 * ...
561 * }
562 *
563 * With the new offset and count parameters, this makes sysfs ABI be able
564 * to support file size more than one page. For example, offset could be
565 * >= 4096.
566 * bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their
567 * cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf()
568 * make those drivers be able to support large bitmask and list after they
569 * move to use bin_attribute. In result, we have to pass the corresponding
570 * parameters such as off, count from bin_attribute show entry to this API.
571 *
572 * The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf()
573 * is similar with cpumap_print_to_pagebuf(), the difference is that
574 * bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption
575 * the destination buffer is exactly one page and won't be more than one page.
576 * cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other
577 * hand, mainly serves bin_attribute which doesn't work with exact one page,
578 * and it can break the size limit of converted decimal list and hexadecimal
579 * bitmask.
580 *
581 * WARNING!
582 *
583 * This function is not a replacement for sprintf() or bitmap_print_to_pagebuf().
584 * It is intended to workaround sysfs limitations discussed above and should be
585 * used carefully in general case for the following reasons:
586 *
587 * - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf().
588 * - Memory complexity is O(nbits), comparing to O(1) for snprintf().
589 * - @off and @count are NOT offset and number of bits to print.
590 * - If printing part of bitmap as list, the resulting string is not a correct
591 * list representation of bitmap. Particularly, some bits within or out of
592 * related interval may be erroneously set or unset. The format of the string
593 * may be broken, so bitmap_parselist-like parser may fail parsing it.
594 * - If printing the whole bitmap as list by parts, user must ensure the order
595 * of calls of the function such that the offset is incremented linearly.
596 * - If printing the whole bitmap as list by parts, user must keep bitmap
597 * unchanged between the very first and very last call. Otherwise concatenated
598 * result may be incorrect, and format may be broken.
599 *
600 * Returns the number of characters actually printed to @buf
601 */
bitmap_print_bitmask_to_buf(char * buf,const unsigned long * maskp,int nmaskbits,loff_t off,size_t count)602 int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
603 int nmaskbits, loff_t off, size_t count)
604 {
605 return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);
606 }
607 EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
608
609 /**
610 * bitmap_print_list_to_buf - convert bitmap to decimal list format ASCII string
611 * @buf: buffer into which string is placed
612 * @maskp: pointer to bitmap to convert
613 * @nmaskbits: size of bitmap, in bits
614 * @off: in the string from which we are copying, We copy to @buf
615 * @count: the maximum number of bytes to print
616 *
617 * Everything is same with the above bitmap_print_bitmask_to_buf() except
618 * the print format.
619 */
bitmap_print_list_to_buf(char * buf,const unsigned long * maskp,int nmaskbits,loff_t off,size_t count)620 int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
621 int nmaskbits, loff_t off, size_t count)
622 {
623 return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);
624 }
625 EXPORT_SYMBOL(bitmap_print_list_to_buf);
626
627 /*
628 * Region 9-38:4/10 describes the following bitmap structure:
629 * 0 9 12 18 38 N
630 * .........****......****......****..................
631 * ^ ^ ^ ^ ^
632 * start off group_len end nbits
633 */
634 struct region {
635 unsigned int start;
636 unsigned int off;
637 unsigned int group_len;
638 unsigned int end;
639 unsigned int nbits;
640 };
641
bitmap_set_region(const struct region * r,unsigned long * bitmap)642 static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
643 {
644 unsigned int start;
645
646 for (start = r->start; start <= r->end; start += r->group_len)
647 bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
648 }
649
bitmap_check_region(const struct region * r)650 static int bitmap_check_region(const struct region *r)
651 {
652 if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
653 return -EINVAL;
654
655 if (r->end >= r->nbits)
656 return -ERANGE;
657
658 return 0;
659 }
660
bitmap_getnum(const char * str,unsigned int * num,unsigned int lastbit)661 static const char *bitmap_getnum(const char *str, unsigned int *num,
662 unsigned int lastbit)
663 {
664 unsigned long long n;
665 unsigned int len;
666
667 if (str[0] == 'N') {
668 *num = lastbit;
669 return str + 1;
670 }
671
672 len = _parse_integer(str, 10, &n);
673 if (!len)
674 return ERR_PTR(-EINVAL);
675 if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
676 return ERR_PTR(-EOVERFLOW);
677
678 *num = n;
679 return str + len;
680 }
681
end_of_str(char c)682 static inline bool end_of_str(char c)
683 {
684 return c == '\0' || c == '\n';
685 }
686
__end_of_region(char c)687 static inline bool __end_of_region(char c)
688 {
689 return isspace(c) || c == ',';
690 }
691
end_of_region(char c)692 static inline bool end_of_region(char c)
693 {
694 return __end_of_region(c) || end_of_str(c);
695 }
696
697 /*
698 * The format allows commas and whitespaces at the beginning
699 * of the region.
700 */
bitmap_find_region(const char * str)701 static const char *bitmap_find_region(const char *str)
702 {
703 while (__end_of_region(*str))
704 str++;
705
706 return end_of_str(*str) ? NULL : str;
707 }
708
bitmap_find_region_reverse(const char * start,const char * end)709 static const char *bitmap_find_region_reverse(const char *start, const char *end)
710 {
711 while (start <= end && __end_of_region(*end))
712 end--;
713
714 return end;
715 }
716
bitmap_parse_region(const char * str,struct region * r)717 static const char *bitmap_parse_region(const char *str, struct region *r)
718 {
719 unsigned int lastbit = r->nbits - 1;
720
721 if (!strncasecmp(str, "all", 3)) {
722 r->start = 0;
723 r->end = lastbit;
724 str += 3;
725
726 goto check_pattern;
727 }
728
729 str = bitmap_getnum(str, &r->start, lastbit);
730 if (IS_ERR(str))
731 return str;
732
733 if (end_of_region(*str))
734 goto no_end;
735
736 if (*str != '-')
737 return ERR_PTR(-EINVAL);
738
739 str = bitmap_getnum(str + 1, &r->end, lastbit);
740 if (IS_ERR(str))
741 return str;
742
743 check_pattern:
744 if (end_of_region(*str))
745 goto no_pattern;
746
747 if (*str != ':')
748 return ERR_PTR(-EINVAL);
749
750 str = bitmap_getnum(str + 1, &r->off, lastbit);
751 if (IS_ERR(str))
752 return str;
753
754 if (*str != '/')
755 return ERR_PTR(-EINVAL);
756
757 return bitmap_getnum(str + 1, &r->group_len, lastbit);
758
759 no_end:
760 r->end = r->start;
761 no_pattern:
762 r->off = r->end + 1;
763 r->group_len = r->end + 1;
764
765 return end_of_str(*str) ? NULL : str;
766 }
767
768 /**
769 * bitmap_parselist - convert list format ASCII string to bitmap
770 * @buf: read user string from this buffer; must be terminated
771 * with a \0 or \n.
772 * @maskp: write resulting mask here
773 * @nmaskbits: number of bits in mask to be written
774 *
775 * Input format is a comma-separated list of decimal numbers and
776 * ranges. Consecutively set bits are shown as two hyphen-separated
777 * decimal numbers, the smallest and largest bit numbers set in
778 * the range.
779 * Optionally each range can be postfixed to denote that only parts of it
780 * should be set. The range will divided to groups of specific size.
781 * From each group will be used only defined amount of bits.
782 * Syntax: range:used_size/group_size
783 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
784 * The value 'N' can be used as a dynamically substituted token for the
785 * maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is
786 * dynamic, so if system changes cause the bitmap width to change, such
787 * as more cores in a CPU list, then any ranges using N will also change.
788 *
789 * Returns: 0 on success, -errno on invalid input strings. Error values:
790 *
791 * - ``-EINVAL``: wrong region format
792 * - ``-EINVAL``: invalid character in string
793 * - ``-ERANGE``: bit number specified too large for mask
794 * - ``-EOVERFLOW``: integer overflow in the input parameters
795 */
bitmap_parselist(const char * buf,unsigned long * maskp,int nmaskbits)796 int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
797 {
798 struct region r;
799 long ret;
800
801 r.nbits = nmaskbits;
802 bitmap_zero(maskp, r.nbits);
803
804 while (buf) {
805 buf = bitmap_find_region(buf);
806 if (buf == NULL)
807 return 0;
808
809 buf = bitmap_parse_region(buf, &r);
810 if (IS_ERR(buf))
811 return PTR_ERR(buf);
812
813 ret = bitmap_check_region(&r);
814 if (ret)
815 return ret;
816
817 bitmap_set_region(&r, maskp);
818 }
819
820 return 0;
821 }
822 EXPORT_SYMBOL(bitmap_parselist);
823
824
825 /**
826 * bitmap_parselist_user() - convert user buffer's list format ASCII
827 * string to bitmap
828 *
829 * @ubuf: pointer to user buffer containing string.
830 * @ulen: buffer size in bytes. If string is smaller than this
831 * then it must be terminated with a \0.
832 * @maskp: pointer to bitmap array that will contain result.
833 * @nmaskbits: size of bitmap, in bits.
834 *
835 * Wrapper for bitmap_parselist(), providing it with user buffer.
836 */
bitmap_parselist_user(const char __user * ubuf,unsigned int ulen,unsigned long * maskp,int nmaskbits)837 int bitmap_parselist_user(const char __user *ubuf,
838 unsigned int ulen, unsigned long *maskp,
839 int nmaskbits)
840 {
841 char *buf;
842 int ret;
843
844 buf = memdup_user_nul(ubuf, ulen);
845 if (IS_ERR(buf))
846 return PTR_ERR(buf);
847
848 ret = bitmap_parselist(buf, maskp, nmaskbits);
849
850 kfree(buf);
851 return ret;
852 }
853 EXPORT_SYMBOL(bitmap_parselist_user);
854
bitmap_get_x32_reverse(const char * start,const char * end,u32 * num)855 static const char *bitmap_get_x32_reverse(const char *start,
856 const char *end, u32 *num)
857 {
858 u32 ret = 0;
859 int c, i;
860
861 for (i = 0; i < 32; i += 4) {
862 c = hex_to_bin(*end--);
863 if (c < 0)
864 return ERR_PTR(-EINVAL);
865
866 ret |= c << i;
867
868 if (start > end || __end_of_region(*end))
869 goto out;
870 }
871
872 if (hex_to_bin(*end--) >= 0)
873 return ERR_PTR(-EOVERFLOW);
874 out:
875 *num = ret;
876 return end;
877 }
878
879 /**
880 * bitmap_parse - convert an ASCII hex string into a bitmap.
881 * @start: pointer to buffer containing string.
882 * @buflen: buffer size in bytes. If string is smaller than this
883 * then it must be terminated with a \0 or \n. In that case,
884 * UINT_MAX may be provided instead of string length.
885 * @maskp: pointer to bitmap array that will contain result.
886 * @nmaskbits: size of bitmap, in bits.
887 *
888 * Commas group hex digits into chunks. Each chunk defines exactly 32
889 * bits of the resultant bitmask. No chunk may specify a value larger
890 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
891 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
892 * characters. Grouping such as "1,,5", ",44", "," or "" is allowed.
893 * Leading, embedded and trailing whitespace accepted.
894 */
bitmap_parse(const char * start,unsigned int buflen,unsigned long * maskp,int nmaskbits)895 int bitmap_parse(const char *start, unsigned int buflen,
896 unsigned long *maskp, int nmaskbits)
897 {
898 const char *end = strnchrnul(start, buflen, '\n') - 1;
899 int chunks = BITS_TO_U32(nmaskbits);
900 u32 *bitmap = (u32 *)maskp;
901 int unset_bit;
902 int chunk;
903
904 for (chunk = 0; ; chunk++) {
905 end = bitmap_find_region_reverse(start, end);
906 if (start > end)
907 break;
908
909 if (!chunks--)
910 return -EOVERFLOW;
911
912 #if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
913 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
914 #else
915 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
916 #endif
917 if (IS_ERR(end))
918 return PTR_ERR(end);
919 }
920
921 unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
922 if (unset_bit < nmaskbits) {
923 bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);
924 return 0;
925 }
926
927 if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)
928 return -EOVERFLOW;
929
930 return 0;
931 }
932 EXPORT_SYMBOL(bitmap_parse);
933
934 /**
935 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
936 * @buf: pointer to a bitmap
937 * @pos: a bit position in @buf (0 <= @pos < @nbits)
938 * @nbits: number of valid bit positions in @buf
939 *
940 * Map the bit at position @pos in @buf (of length @nbits) to the
941 * ordinal of which set bit it is. If it is not set or if @pos
942 * is not a valid bit position, map to -1.
943 *
944 * If for example, just bits 4 through 7 are set in @buf, then @pos
945 * values 4 through 7 will get mapped to 0 through 3, respectively,
946 * and other @pos values will get mapped to -1. When @pos value 7
947 * gets mapped to (returns) @ord value 3 in this example, that means
948 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
949 *
950 * The bit positions 0 through @bits are valid positions in @buf.
951 */
bitmap_pos_to_ord(const unsigned long * buf,unsigned int pos,unsigned int nbits)952 static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
953 {
954 if (pos >= nbits || !test_bit(pos, buf))
955 return -1;
956
957 return __bitmap_weight(buf, pos);
958 }
959
960 /**
961 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
962 * @buf: pointer to bitmap
963 * @ord: ordinal bit position (n-th set bit, n >= 0)
964 * @nbits: number of valid bit positions in @buf
965 *
966 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
967 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
968 * >= weight(buf), returns @nbits.
969 *
970 * If for example, just bits 4 through 7 are set in @buf, then @ord
971 * values 0 through 3 will get mapped to 4 through 7, respectively,
972 * and all other @ord values returns @nbits. When @ord value 3
973 * gets mapped to (returns) @pos value 7 in this example, that means
974 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
975 *
976 * The bit positions 0 through @nbits-1 are valid positions in @buf.
977 */
bitmap_ord_to_pos(const unsigned long * buf,unsigned int ord,unsigned int nbits)978 unsigned int bitmap_ord_to_pos(const unsigned long *buf, unsigned int ord, unsigned int nbits)
979 {
980 unsigned int pos;
981
982 for (pos = find_first_bit(buf, nbits);
983 pos < nbits && ord;
984 pos = find_next_bit(buf, nbits, pos + 1))
985 ord--;
986
987 return pos;
988 }
989
990 /**
991 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
992 * @dst: remapped result
993 * @src: subset to be remapped
994 * @old: defines domain of map
995 * @new: defines range of map
996 * @nbits: number of bits in each of these bitmaps
997 *
998 * Let @old and @new define a mapping of bit positions, such that
999 * whatever position is held by the n-th set bit in @old is mapped
1000 * to the n-th set bit in @new. In the more general case, allowing
1001 * for the possibility that the weight 'w' of @new is less than the
1002 * weight of @old, map the position of the n-th set bit in @old to
1003 * the position of the m-th set bit in @new, where m == n % w.
1004 *
1005 * If either of the @old and @new bitmaps are empty, or if @src and
1006 * @dst point to the same location, then this routine copies @src
1007 * to @dst.
1008 *
1009 * The positions of unset bits in @old are mapped to themselves
1010 * (the identify map).
1011 *
1012 * Apply the above specified mapping to @src, placing the result in
1013 * @dst, clearing any bits previously set in @dst.
1014 *
1015 * For example, lets say that @old has bits 4 through 7 set, and
1016 * @new has bits 12 through 15 set. This defines the mapping of bit
1017 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
1018 * bit positions unchanged. So if say @src comes into this routine
1019 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
1020 * 13 and 15 set.
1021 */
bitmap_remap(unsigned long * dst,const unsigned long * src,const unsigned long * old,const unsigned long * new,unsigned int nbits)1022 void bitmap_remap(unsigned long *dst, const unsigned long *src,
1023 const unsigned long *old, const unsigned long *new,
1024 unsigned int nbits)
1025 {
1026 unsigned int oldbit, w;
1027
1028 if (dst == src) /* following doesn't handle inplace remaps */
1029 return;
1030 bitmap_zero(dst, nbits);
1031
1032 w = bitmap_weight(new, nbits);
1033 for_each_set_bit(oldbit, src, nbits) {
1034 int n = bitmap_pos_to_ord(old, oldbit, nbits);
1035
1036 if (n < 0 || w == 0)
1037 set_bit(oldbit, dst); /* identity map */
1038 else
1039 set_bit(bitmap_ord_to_pos(new, n % w, nbits), dst);
1040 }
1041 }
1042 EXPORT_SYMBOL(bitmap_remap);
1043
1044 /**
1045 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
1046 * @oldbit: bit position to be mapped
1047 * @old: defines domain of map
1048 * @new: defines range of map
1049 * @bits: number of bits in each of these bitmaps
1050 *
1051 * Let @old and @new define a mapping of bit positions, such that
1052 * whatever position is held by the n-th set bit in @old is mapped
1053 * to the n-th set bit in @new. In the more general case, allowing
1054 * for the possibility that the weight 'w' of @new is less than the
1055 * weight of @old, map the position of the n-th set bit in @old to
1056 * the position of the m-th set bit in @new, where m == n % w.
1057 *
1058 * The positions of unset bits in @old are mapped to themselves
1059 * (the identify map).
1060 *
1061 * Apply the above specified mapping to bit position @oldbit, returning
1062 * the new bit position.
1063 *
1064 * For example, lets say that @old has bits 4 through 7 set, and
1065 * @new has bits 12 through 15 set. This defines the mapping of bit
1066 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
1067 * bit positions unchanged. So if say @oldbit is 5, then this routine
1068 * returns 13.
1069 */
bitmap_bitremap(int oldbit,const unsigned long * old,const unsigned long * new,int bits)1070 int bitmap_bitremap(int oldbit, const unsigned long *old,
1071 const unsigned long *new, int bits)
1072 {
1073 int w = bitmap_weight(new, bits);
1074 int n = bitmap_pos_to_ord(old, oldbit, bits);
1075 if (n < 0 || w == 0)
1076 return oldbit;
1077 else
1078 return bitmap_ord_to_pos(new, n % w, bits);
1079 }
1080 EXPORT_SYMBOL(bitmap_bitremap);
1081
1082 #ifdef CONFIG_NUMA
1083 /**
1084 * bitmap_onto - translate one bitmap relative to another
1085 * @dst: resulting translated bitmap
1086 * @orig: original untranslated bitmap
1087 * @relmap: bitmap relative to which translated
1088 * @bits: number of bits in each of these bitmaps
1089 *
1090 * Set the n-th bit of @dst iff there exists some m such that the
1091 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
1092 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
1093 * (If you understood the previous sentence the first time your
1094 * read it, you're overqualified for your current job.)
1095 *
1096 * In other words, @orig is mapped onto (surjectively) @dst,
1097 * using the map { <n, m> | the n-th bit of @relmap is the
1098 * m-th set bit of @relmap }.
1099 *
1100 * Any set bits in @orig above bit number W, where W is the
1101 * weight of (number of set bits in) @relmap are mapped nowhere.
1102 * In particular, if for all bits m set in @orig, m >= W, then
1103 * @dst will end up empty. In situations where the possibility
1104 * of such an empty result is not desired, one way to avoid it is
1105 * to use the bitmap_fold() operator, below, to first fold the
1106 * @orig bitmap over itself so that all its set bits x are in the
1107 * range 0 <= x < W. The bitmap_fold() operator does this by
1108 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
1109 *
1110 * Example [1] for bitmap_onto():
1111 * Let's say @relmap has bits 30-39 set, and @orig has bits
1112 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
1113 * @dst will have bits 31, 33, 35, 37 and 39 set.
1114 *
1115 * When bit 0 is set in @orig, it means turn on the bit in
1116 * @dst corresponding to whatever is the first bit (if any)
1117 * that is turned on in @relmap. Since bit 0 was off in the
1118 * above example, we leave off that bit (bit 30) in @dst.
1119 *
1120 * When bit 1 is set in @orig (as in the above example), it
1121 * means turn on the bit in @dst corresponding to whatever
1122 * is the second bit that is turned on in @relmap. The second
1123 * bit in @relmap that was turned on in the above example was
1124 * bit 31, so we turned on bit 31 in @dst.
1125 *
1126 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
1127 * because they were the 4th, 6th, 8th and 10th set bits
1128 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
1129 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
1130 *
1131 * When bit 11 is set in @orig, it means turn on the bit in
1132 * @dst corresponding to whatever is the twelfth bit that is
1133 * turned on in @relmap. In the above example, there were
1134 * only ten bits turned on in @relmap (30..39), so that bit
1135 * 11 was set in @orig had no affect on @dst.
1136 *
1137 * Example [2] for bitmap_fold() + bitmap_onto():
1138 * Let's say @relmap has these ten bits set::
1139 *
1140 * 40 41 42 43 45 48 53 61 74 95
1141 *
1142 * (for the curious, that's 40 plus the first ten terms of the
1143 * Fibonacci sequence.)
1144 *
1145 * Further lets say we use the following code, invoking
1146 * bitmap_fold() then bitmap_onto, as suggested above to
1147 * avoid the possibility of an empty @dst result::
1148 *
1149 * unsigned long *tmp; // a temporary bitmap's bits
1150 *
1151 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
1152 * bitmap_onto(dst, tmp, relmap, bits);
1153 *
1154 * Then this table shows what various values of @dst would be, for
1155 * various @orig's. I list the zero-based positions of each set bit.
1156 * The tmp column shows the intermediate result, as computed by
1157 * using bitmap_fold() to fold the @orig bitmap modulo ten
1158 * (the weight of @relmap):
1159 *
1160 * =============== ============== =================
1161 * @orig tmp @dst
1162 * 0 0 40
1163 * 1 1 41
1164 * 9 9 95
1165 * 10 0 40 [#f1]_
1166 * 1 3 5 7 1 3 5 7 41 43 48 61
1167 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
1168 * 0 9 18 27 0 9 8 7 40 61 74 95
1169 * 0 10 20 30 0 40
1170 * 0 11 22 33 0 1 2 3 40 41 42 43
1171 * 0 12 24 36 0 2 4 6 40 42 45 53
1172 * 78 102 211 1 2 8 41 42 74 [#f1]_
1173 * =============== ============== =================
1174 *
1175 * .. [#f1]
1176 *
1177 * For these marked lines, if we hadn't first done bitmap_fold()
1178 * into tmp, then the @dst result would have been empty.
1179 *
1180 * If either of @orig or @relmap is empty (no set bits), then @dst
1181 * will be returned empty.
1182 *
1183 * If (as explained above) the only set bits in @orig are in positions
1184 * m where m >= W, (where W is the weight of @relmap) then @dst will
1185 * once again be returned empty.
1186 *
1187 * All bits in @dst not set by the above rule are cleared.
1188 */
bitmap_onto(unsigned long * dst,const unsigned long * orig,const unsigned long * relmap,unsigned int bits)1189 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
1190 const unsigned long *relmap, unsigned int bits)
1191 {
1192 unsigned int n, m; /* same meaning as in above comment */
1193
1194 if (dst == orig) /* following doesn't handle inplace mappings */
1195 return;
1196 bitmap_zero(dst, bits);
1197
1198 /*
1199 * The following code is a more efficient, but less
1200 * obvious, equivalent to the loop:
1201 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
1202 * n = bitmap_ord_to_pos(orig, m, bits);
1203 * if (test_bit(m, orig))
1204 * set_bit(n, dst);
1205 * }
1206 */
1207
1208 m = 0;
1209 for_each_set_bit(n, relmap, bits) {
1210 /* m == bitmap_pos_to_ord(relmap, n, bits) */
1211 if (test_bit(m, orig))
1212 set_bit(n, dst);
1213 m++;
1214 }
1215 }
1216
1217 /**
1218 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1219 * @dst: resulting smaller bitmap
1220 * @orig: original larger bitmap
1221 * @sz: specified size
1222 * @nbits: number of bits in each of these bitmaps
1223 *
1224 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1225 * Clear all other bits in @dst. See further the comment and
1226 * Example [2] for bitmap_onto() for why and how to use this.
1227 */
bitmap_fold(unsigned long * dst,const unsigned long * orig,unsigned int sz,unsigned int nbits)1228 void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1229 unsigned int sz, unsigned int nbits)
1230 {
1231 unsigned int oldbit;
1232
1233 if (dst == orig) /* following doesn't handle inplace mappings */
1234 return;
1235 bitmap_zero(dst, nbits);
1236
1237 for_each_set_bit(oldbit, orig, nbits)
1238 set_bit(oldbit % sz, dst);
1239 }
1240 #endif /* CONFIG_NUMA */
1241
1242 /*
1243 * Common code for bitmap_*_region() routines.
1244 * bitmap: array of unsigned longs corresponding to the bitmap
1245 * pos: the beginning of the region
1246 * order: region size (log base 2 of number of bits)
1247 * reg_op: operation(s) to perform on that region of bitmap
1248 *
1249 * Can set, verify and/or release a region of bits in a bitmap,
1250 * depending on which combination of REG_OP_* flag bits is set.
1251 *
1252 * A region of a bitmap is a sequence of bits in the bitmap, of
1253 * some size '1 << order' (a power of two), aligned to that same
1254 * '1 << order' power of two.
1255 *
1256 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1257 * Returns 0 in all other cases and reg_ops.
1258 */
1259
1260 enum {
1261 REG_OP_ISFREE, /* true if region is all zero bits */
1262 REG_OP_ALLOC, /* set all bits in region */
1263 REG_OP_RELEASE, /* clear all bits in region */
1264 };
1265
__reg_op(unsigned long * bitmap,unsigned int pos,int order,int reg_op)1266 static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
1267 {
1268 int nbits_reg; /* number of bits in region */
1269 int index; /* index first long of region in bitmap */
1270 int offset; /* bit offset region in bitmap[index] */
1271 int nlongs_reg; /* num longs spanned by region in bitmap */
1272 int nbitsinlong; /* num bits of region in each spanned long */
1273 unsigned long mask; /* bitmask for one long of region */
1274 int i; /* scans bitmap by longs */
1275 int ret = 0; /* return value */
1276
1277 /*
1278 * Either nlongs_reg == 1 (for small orders that fit in one long)
1279 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1280 */
1281 nbits_reg = 1 << order;
1282 index = pos / BITS_PER_LONG;
1283 offset = pos - (index * BITS_PER_LONG);
1284 nlongs_reg = BITS_TO_LONGS(nbits_reg);
1285 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1286
1287 /*
1288 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1289 * overflows if nbitsinlong == BITS_PER_LONG.
1290 */
1291 mask = (1UL << (nbitsinlong - 1));
1292 mask += mask - 1;
1293 mask <<= offset;
1294
1295 switch (reg_op) {
1296 case REG_OP_ISFREE:
1297 for (i = 0; i < nlongs_reg; i++) {
1298 if (bitmap[index + i] & mask)
1299 goto done;
1300 }
1301 ret = 1; /* all bits in region free (zero) */
1302 break;
1303
1304 case REG_OP_ALLOC:
1305 for (i = 0; i < nlongs_reg; i++)
1306 bitmap[index + i] |= mask;
1307 break;
1308
1309 case REG_OP_RELEASE:
1310 for (i = 0; i < nlongs_reg; i++)
1311 bitmap[index + i] &= ~mask;
1312 break;
1313 }
1314 done:
1315 return ret;
1316 }
1317
1318 /**
1319 * bitmap_find_free_region - find a contiguous aligned mem region
1320 * @bitmap: array of unsigned longs corresponding to the bitmap
1321 * @bits: number of bits in the bitmap
1322 * @order: region size (log base 2 of number of bits) to find
1323 *
1324 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1325 * allocate them (set them to one). Only consider regions of length
1326 * a power (@order) of two, aligned to that power of two, which
1327 * makes the search algorithm much faster.
1328 *
1329 * Return the bit offset in bitmap of the allocated region,
1330 * or -errno on failure.
1331 */
bitmap_find_free_region(unsigned long * bitmap,unsigned int bits,int order)1332 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
1333 {
1334 unsigned int pos, end; /* scans bitmap by regions of size order */
1335
1336 for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
1337 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1338 continue;
1339 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1340 return pos;
1341 }
1342 return -ENOMEM;
1343 }
1344 EXPORT_SYMBOL(bitmap_find_free_region);
1345
1346 /**
1347 * bitmap_release_region - release allocated bitmap region
1348 * @bitmap: array of unsigned longs corresponding to the bitmap
1349 * @pos: beginning of bit region to release
1350 * @order: region size (log base 2 of number of bits) to release
1351 *
1352 * This is the complement to __bitmap_find_free_region() and releases
1353 * the found region (by clearing it in the bitmap).
1354 *
1355 * No return value.
1356 */
bitmap_release_region(unsigned long * bitmap,unsigned int pos,int order)1357 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
1358 {
1359 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1360 }
1361 EXPORT_SYMBOL(bitmap_release_region);
1362
1363 /**
1364 * bitmap_allocate_region - allocate bitmap region
1365 * @bitmap: array of unsigned longs corresponding to the bitmap
1366 * @pos: beginning of bit region to allocate
1367 * @order: region size (log base 2 of number of bits) to allocate
1368 *
1369 * Allocate (set bits in) a specified region of a bitmap.
1370 *
1371 * Return 0 on success, or %-EBUSY if specified region wasn't
1372 * free (not all bits were zero).
1373 */
bitmap_allocate_region(unsigned long * bitmap,unsigned int pos,int order)1374 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
1375 {
1376 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1377 return -EBUSY;
1378 return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1379 }
1380 EXPORT_SYMBOL(bitmap_allocate_region);
1381
1382 /**
1383 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1384 * @dst: destination buffer
1385 * @src: bitmap to copy
1386 * @nbits: number of bits in the bitmap
1387 *
1388 * Require nbits % BITS_PER_LONG == 0.
1389 */
1390 #ifdef __BIG_ENDIAN
bitmap_copy_le(unsigned long * dst,const unsigned long * src,unsigned int nbits)1391 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
1392 {
1393 unsigned int i;
1394
1395 for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1396 if (BITS_PER_LONG == 64)
1397 dst[i] = cpu_to_le64(src[i]);
1398 else
1399 dst[i] = cpu_to_le32(src[i]);
1400 }
1401 }
1402 EXPORT_SYMBOL(bitmap_copy_le);
1403 #endif
1404
bitmap_alloc(unsigned int nbits,gfp_t flags)1405 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
1406 {
1407 return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
1408 flags);
1409 }
1410 EXPORT_SYMBOL(bitmap_alloc);
1411
bitmap_zalloc(unsigned int nbits,gfp_t flags)1412 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
1413 {
1414 return bitmap_alloc(nbits, flags | __GFP_ZERO);
1415 }
1416 EXPORT_SYMBOL(bitmap_zalloc);
1417
bitmap_alloc_node(unsigned int nbits,gfp_t flags,int node)1418 unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node)
1419 {
1420 return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long),
1421 flags, node);
1422 }
1423 EXPORT_SYMBOL(bitmap_alloc_node);
1424
bitmap_zalloc_node(unsigned int nbits,gfp_t flags,int node)1425 unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)
1426 {
1427 return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);
1428 }
1429 EXPORT_SYMBOL(bitmap_zalloc_node);
1430
bitmap_free(const unsigned long * bitmap)1431 void bitmap_free(const unsigned long *bitmap)
1432 {
1433 kfree(bitmap);
1434 }
1435 EXPORT_SYMBOL(bitmap_free);
1436
devm_bitmap_free(void * data)1437 static void devm_bitmap_free(void *data)
1438 {
1439 unsigned long *bitmap = data;
1440
1441 bitmap_free(bitmap);
1442 }
1443
devm_bitmap_alloc(struct device * dev,unsigned int nbits,gfp_t flags)1444 unsigned long *devm_bitmap_alloc(struct device *dev,
1445 unsigned int nbits, gfp_t flags)
1446 {
1447 unsigned long *bitmap;
1448 int ret;
1449
1450 bitmap = bitmap_alloc(nbits, flags);
1451 if (!bitmap)
1452 return NULL;
1453
1454 ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);
1455 if (ret)
1456 return NULL;
1457
1458 return bitmap;
1459 }
1460 EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
1461
devm_bitmap_zalloc(struct device * dev,unsigned int nbits,gfp_t flags)1462 unsigned long *devm_bitmap_zalloc(struct device *dev,
1463 unsigned int nbits, gfp_t flags)
1464 {
1465 return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);
1466 }
1467 EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);
1468
1469 #if BITS_PER_LONG == 64
1470 /**
1471 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
1472 * @bitmap: array of unsigned longs, the destination bitmap
1473 * @buf: array of u32 (in host byte order), the source bitmap
1474 * @nbits: number of bits in @bitmap
1475 */
bitmap_from_arr32(unsigned long * bitmap,const u32 * buf,unsigned int nbits)1476 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
1477 {
1478 unsigned int i, halfwords;
1479
1480 halfwords = DIV_ROUND_UP(nbits, 32);
1481 for (i = 0; i < halfwords; i++) {
1482 bitmap[i/2] = (unsigned long) buf[i];
1483 if (++i < halfwords)
1484 bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
1485 }
1486
1487 /* Clear tail bits in last word beyond nbits. */
1488 if (nbits % BITS_PER_LONG)
1489 bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
1490 }
1491 EXPORT_SYMBOL(bitmap_from_arr32);
1492
1493 /**
1494 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
1495 * @buf: array of u32 (in host byte order), the dest bitmap
1496 * @bitmap: array of unsigned longs, the source bitmap
1497 * @nbits: number of bits in @bitmap
1498 */
bitmap_to_arr32(u32 * buf,const unsigned long * bitmap,unsigned int nbits)1499 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
1500 {
1501 unsigned int i, halfwords;
1502
1503 halfwords = DIV_ROUND_UP(nbits, 32);
1504 for (i = 0; i < halfwords; i++) {
1505 buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
1506 if (++i < halfwords)
1507 buf[i] = (u32) (bitmap[i/2] >> 32);
1508 }
1509
1510 /* Clear tail bits in last element of array beyond nbits. */
1511 if (nbits % BITS_PER_LONG)
1512 buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
1513 }
1514 EXPORT_SYMBOL(bitmap_to_arr32);
1515 #endif
1516
1517 #if (BITS_PER_LONG == 32) && defined(__BIG_ENDIAN)
1518 /**
1519 * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap
1520 * @bitmap: array of unsigned longs, the destination bitmap
1521 * @buf: array of u64 (in host byte order), the source bitmap
1522 * @nbits: number of bits in @bitmap
1523 */
bitmap_from_arr64(unsigned long * bitmap,const u64 * buf,unsigned int nbits)1524 void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)
1525 {
1526 int n;
1527
1528 for (n = nbits; n > 0; n -= 64) {
1529 u64 val = *buf++;
1530
1531 *bitmap++ = val;
1532 if (n > 32)
1533 *bitmap++ = val >> 32;
1534 }
1535
1536 /*
1537 * Clear tail bits in the last word beyond nbits.
1538 *
1539 * Negative index is OK because here we point to the word next
1540 * to the last word of the bitmap, except for nbits == 0, which
1541 * is tested implicitly.
1542 */
1543 if (nbits % BITS_PER_LONG)
1544 bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);
1545 }
1546 EXPORT_SYMBOL(bitmap_from_arr64);
1547
1548 /**
1549 * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits
1550 * @buf: array of u64 (in host byte order), the dest bitmap
1551 * @bitmap: array of unsigned longs, the source bitmap
1552 * @nbits: number of bits in @bitmap
1553 */
bitmap_to_arr64(u64 * buf,const unsigned long * bitmap,unsigned int nbits)1554 void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
1555 {
1556 const unsigned long *end = bitmap + BITS_TO_LONGS(nbits);
1557
1558 while (bitmap < end) {
1559 *buf = *bitmap++;
1560 if (bitmap < end)
1561 *buf |= (u64)(*bitmap++) << 32;
1562 buf++;
1563 }
1564
1565 /* Clear tail bits in the last element of array beyond nbits. */
1566 if (nbits % 64)
1567 buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);
1568 }
1569 EXPORT_SYMBOL(bitmap_to_arr64);
1570 #endif
1571