1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_BITMAP_H
3 #define __LINUX_BITMAP_H
4 
5 #ifndef __ASSEMBLY__
6 
7 #include <linux/align.h>
8 #include <linux/bitops.h>
9 #include <linux/limits.h>
10 #include <linux/string.h>
11 #include <linux/types.h>
12 
13 struct device;
14 
15 /*
16  * bitmaps provide bit arrays that consume one or more unsigned
17  * longs.  The bitmap interface and available operations are listed
18  * here, in bitmap.h
19  *
20  * Function implementations generic to all architectures are in
21  * lib/bitmap.c.  Functions implementations that are architecture
22  * specific are in various include/asm-<arch>/bitops.h headers
23  * and other arch/<arch> specific files.
24  *
25  * See lib/bitmap.c for more details.
26  */
27 
28 /**
29  * DOC: bitmap overview
30  *
31  * The available bitmap operations and their rough meaning in the
32  * case that the bitmap is a single unsigned long are thus:
33  *
34  * The generated code is more efficient when nbits is known at
35  * compile-time and at most BITS_PER_LONG.
36  *
37  * ::
38  *
39  *  bitmap_zero(dst, nbits)                     *dst = 0UL
40  *  bitmap_fill(dst, nbits)                     *dst = ~0UL
41  *  bitmap_copy(dst, src, nbits)                *dst = *src
42  *  bitmap_and(dst, src1, src2, nbits)          *dst = *src1 & *src2
43  *  bitmap_or(dst, src1, src2, nbits)           *dst = *src1 | *src2
44  *  bitmap_xor(dst, src1, src2, nbits)          *dst = *src1 ^ *src2
45  *  bitmap_andnot(dst, src1, src2, nbits)       *dst = *src1 & ~(*src2)
46  *  bitmap_complement(dst, src, nbits)          *dst = ~(*src)
47  *  bitmap_equal(src1, src2, nbits)             Are *src1 and *src2 equal?
48  *  bitmap_intersects(src1, src2, nbits)        Do *src1 and *src2 overlap?
49  *  bitmap_subset(src1, src2, nbits)            Is *src1 a subset of *src2?
50  *  bitmap_empty(src, nbits)                    Are all bits zero in *src?
51  *  bitmap_full(src, nbits)                     Are all bits set in *src?
52  *  bitmap_weight(src, nbits)                   Hamming Weight: number set bits
53  *  bitmap_set(dst, pos, nbits)                 Set specified bit area
54  *  bitmap_clear(dst, pos, nbits)               Clear specified bit area
55  *  bitmap_find_next_zero_area(buf, len, pos, n, mask)  Find bit free area
56  *  bitmap_find_next_zero_area_off(buf, len, pos, n, mask, mask_off)  as above
57  *  bitmap_next_clear_region(map, &start, &end, nbits)  Find next clear region
58  *  bitmap_next_set_region(map, &start, &end, nbits)  Find next set region
59  *  bitmap_for_each_clear_region(map, rs, re, start, end)
60  *  						Iterate over all clear regions
61  *  bitmap_for_each_set_region(map, rs, re, start, end)
62  *  						Iterate over all set regions
63  *  bitmap_shift_right(dst, src, n, nbits)      *dst = *src >> n
64  *  bitmap_shift_left(dst, src, n, nbits)       *dst = *src << n
65  *  bitmap_cut(dst, src, first, n, nbits)       Cut n bits from first, copy rest
66  *  bitmap_replace(dst, old, new, mask, nbits)  *dst = (*old & ~(*mask)) | (*new & *mask)
67  *  bitmap_remap(dst, src, old, new, nbits)     *dst = map(old, new)(src)
68  *  bitmap_bitremap(oldbit, old, new, nbits)    newbit = map(old, new)(oldbit)
69  *  bitmap_onto(dst, orig, relmap, nbits)       *dst = orig relative to relmap
70  *  bitmap_fold(dst, orig, sz, nbits)           dst bits = orig bits mod sz
71  *  bitmap_parse(buf, buflen, dst, nbits)       Parse bitmap dst from kernel buf
72  *  bitmap_parse_user(ubuf, ulen, dst, nbits)   Parse bitmap dst from user buf
73  *  bitmap_parselist(buf, dst, nbits)           Parse bitmap dst from kernel buf
74  *  bitmap_parselist_user(buf, dst, nbits)      Parse bitmap dst from user buf
75  *  bitmap_find_free_region(bitmap, bits, order)  Find and allocate bit region
76  *  bitmap_release_region(bitmap, pos, order)   Free specified bit region
77  *  bitmap_allocate_region(bitmap, pos, order)  Allocate specified bit region
78  *  bitmap_from_arr32(dst, buf, nbits)          Copy nbits from u32[] buf to dst
79  *  bitmap_to_arr32(buf, src, nbits)            Copy nbits from buf to u32[] dst
80  *  bitmap_get_value8(map, start)               Get 8bit value from map at start
81  *  bitmap_set_value8(map, value, start)        Set 8bit value to map at start
82  *
83  * Note, bitmap_zero() and bitmap_fill() operate over the region of
84  * unsigned longs, that is, bits behind bitmap till the unsigned long
85  * boundary will be zeroed or filled as well. Consider to use
86  * bitmap_clear() or bitmap_set() to make explicit zeroing or filling
87  * respectively.
88  */
89 
90 /**
91  * DOC: bitmap bitops
92  *
93  * Also the following operations in asm/bitops.h apply to bitmaps.::
94  *
95  *  set_bit(bit, addr)                  *addr |= bit
96  *  clear_bit(bit, addr)                *addr &= ~bit
97  *  change_bit(bit, addr)               *addr ^= bit
98  *  test_bit(bit, addr)                 Is bit set in *addr?
99  *  test_and_set_bit(bit, addr)         Set bit and return old value
100  *  test_and_clear_bit(bit, addr)       Clear bit and return old value
101  *  test_and_change_bit(bit, addr)      Change bit and return old value
102  *  find_first_zero_bit(addr, nbits)    Position first zero bit in *addr
103  *  find_first_bit(addr, nbits)         Position first set bit in *addr
104  *  find_next_zero_bit(addr, nbits, bit)
105  *                                      Position next zero bit in *addr >= bit
106  *  find_next_bit(addr, nbits, bit)     Position next set bit in *addr >= bit
107  *  find_next_and_bit(addr1, addr2, nbits, bit)
108  *                                      Same as find_next_bit, but in
109  *                                      (*addr1 & *addr2)
110  *
111  */
112 
113 /**
114  * DOC: declare bitmap
115  * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
116  * to declare an array named 'name' of just enough unsigned longs to
117  * contain all bit positions from 0 to 'bits' - 1.
118  */
119 
120 /*
121  * Allocation and deallocation of bitmap.
122  * Provided in lib/bitmap.c to avoid circular dependency.
123  */
124 unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags);
125 unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags);
126 unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node);
127 unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node);
128 void bitmap_free(const unsigned long *bitmap);
129 
130 /* Managed variants of the above. */
131 unsigned long *devm_bitmap_alloc(struct device *dev,
132 				 unsigned int nbits, gfp_t flags);
133 unsigned long *devm_bitmap_zalloc(struct device *dev,
134 				  unsigned int nbits, gfp_t flags);
135 
136 /*
137  * lib/bitmap.c provides these functions:
138  */
139 
140 int __bitmap_equal(const unsigned long *bitmap1,
141 		   const unsigned long *bitmap2, unsigned int nbits);
142 bool __pure __bitmap_or_equal(const unsigned long *src1,
143 			      const unsigned long *src2,
144 			      const unsigned long *src3,
145 			      unsigned int nbits);
146 void __bitmap_complement(unsigned long *dst, const unsigned long *src,
147 			 unsigned int nbits);
148 void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
149 			  unsigned int shift, unsigned int nbits);
150 void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
151 			 unsigned int shift, unsigned int nbits);
152 void bitmap_cut(unsigned long *dst, const unsigned long *src,
153 		unsigned int first, unsigned int cut, unsigned int nbits);
154 int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
155 		 const unsigned long *bitmap2, unsigned int nbits);
156 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
157 		 const unsigned long *bitmap2, unsigned int nbits);
158 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
159 		  const unsigned long *bitmap2, unsigned int nbits);
160 int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
161 		    const unsigned long *bitmap2, unsigned int nbits);
162 void __bitmap_replace(unsigned long *dst,
163 		      const unsigned long *old, const unsigned long *new,
164 		      const unsigned long *mask, unsigned int nbits);
165 int __bitmap_intersects(const unsigned long *bitmap1,
166 			const unsigned long *bitmap2, unsigned int nbits);
167 int __bitmap_subset(const unsigned long *bitmap1,
168 		    const unsigned long *bitmap2, unsigned int nbits);
169 int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
170 void __bitmap_set(unsigned long *map, unsigned int start, int len);
171 void __bitmap_clear(unsigned long *map, unsigned int start, int len);
172 
173 unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
174 					     unsigned long size,
175 					     unsigned long start,
176 					     unsigned int nr,
177 					     unsigned long align_mask,
178 					     unsigned long align_offset);
179 
180 /**
181  * bitmap_find_next_zero_area - find a contiguous aligned zero area
182  * @map: The address to base the search on
183  * @size: The bitmap size in bits
184  * @start: The bitnumber to start searching at
185  * @nr: The number of zeroed bits we're looking for
186  * @align_mask: Alignment mask for zero area
187  *
188  * The @align_mask should be one less than a power of 2; the effect is that
189  * the bit offset of all zero areas this function finds is multiples of that
190  * power of 2. A @align_mask of 0 means no alignment is required.
191  */
192 static inline unsigned long
bitmap_find_next_zero_area(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,unsigned long align_mask)193 bitmap_find_next_zero_area(unsigned long *map,
194 			   unsigned long size,
195 			   unsigned long start,
196 			   unsigned int nr,
197 			   unsigned long align_mask)
198 {
199 	return bitmap_find_next_zero_area_off(map, size, start, nr,
200 					      align_mask, 0);
201 }
202 
203 int bitmap_parse(const char *buf, unsigned int buflen,
204 			unsigned long *dst, int nbits);
205 int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
206 			unsigned long *dst, int nbits);
207 int bitmap_parselist(const char *buf, unsigned long *maskp,
208 			int nmaskbits);
209 int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
210 			unsigned long *dst, int nbits);
211 void bitmap_remap(unsigned long *dst, const unsigned long *src,
212 		const unsigned long *old, const unsigned long *new, unsigned int nbits);
213 int bitmap_bitremap(int oldbit,
214 		const unsigned long *old, const unsigned long *new, int bits);
215 void bitmap_onto(unsigned long *dst, const unsigned long *orig,
216 		const unsigned long *relmap, unsigned int bits);
217 void bitmap_fold(unsigned long *dst, const unsigned long *orig,
218 		unsigned int sz, unsigned int nbits);
219 int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order);
220 void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order);
221 int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order);
222 
223 #ifdef __BIG_ENDIAN
224 void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits);
225 #else
226 #define bitmap_copy_le bitmap_copy
227 #endif
228 unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits);
229 int bitmap_print_to_pagebuf(bool list, char *buf,
230 				   const unsigned long *maskp, int nmaskbits);
231 
232 extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
233 				      int nmaskbits, loff_t off, size_t count);
234 
235 extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
236 				      int nmaskbits, loff_t off, size_t count);
237 
238 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
239 #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
240 
bitmap_zero(unsigned long * dst,unsigned int nbits)241 static inline void bitmap_zero(unsigned long *dst, unsigned int nbits)
242 {
243 	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
244 	memset(dst, 0, len);
245 }
246 
bitmap_fill(unsigned long * dst,unsigned int nbits)247 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
248 {
249 	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
250 	memset(dst, 0xff, len);
251 }
252 
bitmap_copy(unsigned long * dst,const unsigned long * src,unsigned int nbits)253 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
254 			unsigned int nbits)
255 {
256 	unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
257 	memcpy(dst, src, len);
258 }
259 
260 /*
261  * Copy bitmap and clear tail bits in last word.
262  */
bitmap_copy_clear_tail(unsigned long * dst,const unsigned long * src,unsigned int nbits)263 static inline void bitmap_copy_clear_tail(unsigned long *dst,
264 		const unsigned long *src, unsigned int nbits)
265 {
266 	bitmap_copy(dst, src, nbits);
267 	if (nbits % BITS_PER_LONG)
268 		dst[nbits / BITS_PER_LONG] &= BITMAP_LAST_WORD_MASK(nbits);
269 }
270 
271 /*
272  * On 32-bit systems bitmaps are represented as u32 arrays internally, and
273  * therefore conversion is not needed when copying data from/to arrays of u32.
274  */
275 #if BITS_PER_LONG == 64
276 void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf,
277 							unsigned int nbits);
278 void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
279 							unsigned int nbits);
280 #else
281 #define bitmap_from_arr32(bitmap, buf, nbits)			\
282 	bitmap_copy_clear_tail((unsigned long *) (bitmap),	\
283 			(const unsigned long *) (buf), (nbits))
284 #define bitmap_to_arr32(buf, bitmap, nbits)			\
285 	bitmap_copy_clear_tail((unsigned long *) (buf),		\
286 			(const unsigned long *) (bitmap), (nbits))
287 #endif
288 
bitmap_and(unsigned long * dst,const unsigned long * src1,const unsigned long * src2,unsigned int nbits)289 static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
290 			const unsigned long *src2, unsigned int nbits)
291 {
292 	if (small_const_nbits(nbits))
293 		return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
294 	return __bitmap_and(dst, src1, src2, nbits);
295 }
296 
bitmap_or(unsigned long * dst,const unsigned long * src1,const unsigned long * src2,unsigned int nbits)297 static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
298 			const unsigned long *src2, unsigned int nbits)
299 {
300 	if (small_const_nbits(nbits))
301 		*dst = *src1 | *src2;
302 	else
303 		__bitmap_or(dst, src1, src2, nbits);
304 }
305 
bitmap_xor(unsigned long * dst,const unsigned long * src1,const unsigned long * src2,unsigned int nbits)306 static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
307 			const unsigned long *src2, unsigned int nbits)
308 {
309 	if (small_const_nbits(nbits))
310 		*dst = *src1 ^ *src2;
311 	else
312 		__bitmap_xor(dst, src1, src2, nbits);
313 }
314 
bitmap_andnot(unsigned long * dst,const unsigned long * src1,const unsigned long * src2,unsigned int nbits)315 static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
316 			const unsigned long *src2, unsigned int nbits)
317 {
318 	if (small_const_nbits(nbits))
319 		return (*dst = *src1 & ~(*src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
320 	return __bitmap_andnot(dst, src1, src2, nbits);
321 }
322 
bitmap_complement(unsigned long * dst,const unsigned long * src,unsigned int nbits)323 static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
324 			unsigned int nbits)
325 {
326 	if (small_const_nbits(nbits))
327 		*dst = ~(*src);
328 	else
329 		__bitmap_complement(dst, src, nbits);
330 }
331 
332 #ifdef __LITTLE_ENDIAN
333 #define BITMAP_MEM_ALIGNMENT 8
334 #else
335 #define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
336 #endif
337 #define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
338 
bitmap_equal(const unsigned long * src1,const unsigned long * src2,unsigned int nbits)339 static inline int bitmap_equal(const unsigned long *src1,
340 			const unsigned long *src2, unsigned int nbits)
341 {
342 	if (small_const_nbits(nbits))
343 		return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
344 	if (__builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
345 	    IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
346 		return !memcmp(src1, src2, nbits / 8);
347 	return __bitmap_equal(src1, src2, nbits);
348 }
349 
350 /**
351  * bitmap_or_equal - Check whether the or of two bitmaps is equal to a third
352  * @src1:	Pointer to bitmap 1
353  * @src2:	Pointer to bitmap 2 will be or'ed with bitmap 1
354  * @src3:	Pointer to bitmap 3. Compare to the result of *@src1 | *@src2
355  * @nbits:	number of bits in each of these bitmaps
356  *
357  * Returns: True if (*@src1 | *@src2) == *@src3, false otherwise
358  */
bitmap_or_equal(const unsigned long * src1,const unsigned long * src2,const unsigned long * src3,unsigned int nbits)359 static inline bool bitmap_or_equal(const unsigned long *src1,
360 				   const unsigned long *src2,
361 				   const unsigned long *src3,
362 				   unsigned int nbits)
363 {
364 	if (!small_const_nbits(nbits))
365 		return __bitmap_or_equal(src1, src2, src3, nbits);
366 
367 	return !(((*src1 | *src2) ^ *src3) & BITMAP_LAST_WORD_MASK(nbits));
368 }
369 
bitmap_intersects(const unsigned long * src1,const unsigned long * src2,unsigned int nbits)370 static inline int bitmap_intersects(const unsigned long *src1,
371 			const unsigned long *src2, unsigned int nbits)
372 {
373 	if (small_const_nbits(nbits))
374 		return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
375 	else
376 		return __bitmap_intersects(src1, src2, nbits);
377 }
378 
bitmap_subset(const unsigned long * src1,const unsigned long * src2,unsigned int nbits)379 static inline int bitmap_subset(const unsigned long *src1,
380 			const unsigned long *src2, unsigned int nbits)
381 {
382 	if (small_const_nbits(nbits))
383 		return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
384 	else
385 		return __bitmap_subset(src1, src2, nbits);
386 }
387 
bitmap_empty(const unsigned long * src,unsigned nbits)388 static inline bool bitmap_empty(const unsigned long *src, unsigned nbits)
389 {
390 	if (small_const_nbits(nbits))
391 		return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
392 
393 	return find_first_bit(src, nbits) == nbits;
394 }
395 
bitmap_full(const unsigned long * src,unsigned int nbits)396 static inline bool bitmap_full(const unsigned long *src, unsigned int nbits)
397 {
398 	if (small_const_nbits(nbits))
399 		return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
400 
401 	return find_first_zero_bit(src, nbits) == nbits;
402 }
403 
bitmap_weight(const unsigned long * src,unsigned int nbits)404 static __always_inline int bitmap_weight(const unsigned long *src, unsigned int nbits)
405 {
406 	if (small_const_nbits(nbits))
407 		return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
408 	return __bitmap_weight(src, nbits);
409 }
410 
bitmap_set(unsigned long * map,unsigned int start,unsigned int nbits)411 static __always_inline void bitmap_set(unsigned long *map, unsigned int start,
412 		unsigned int nbits)
413 {
414 	if (__builtin_constant_p(nbits) && nbits == 1)
415 		__set_bit(start, map);
416 	else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
417 		 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
418 		 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
419 		 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
420 		memset((char *)map + start / 8, 0xff, nbits / 8);
421 	else
422 		__bitmap_set(map, start, nbits);
423 }
424 
bitmap_clear(unsigned long * map,unsigned int start,unsigned int nbits)425 static __always_inline void bitmap_clear(unsigned long *map, unsigned int start,
426 		unsigned int nbits)
427 {
428 	if (__builtin_constant_p(nbits) && nbits == 1)
429 		__clear_bit(start, map);
430 	else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
431 		 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
432 		 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
433 		 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
434 		memset((char *)map + start / 8, 0, nbits / 8);
435 	else
436 		__bitmap_clear(map, start, nbits);
437 }
438 
bitmap_shift_right(unsigned long * dst,const unsigned long * src,unsigned int shift,unsigned int nbits)439 static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src,
440 				unsigned int shift, unsigned int nbits)
441 {
442 	if (small_const_nbits(nbits))
443 		*dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift;
444 	else
445 		__bitmap_shift_right(dst, src, shift, nbits);
446 }
447 
bitmap_shift_left(unsigned long * dst,const unsigned long * src,unsigned int shift,unsigned int nbits)448 static inline void bitmap_shift_left(unsigned long *dst, const unsigned long *src,
449 				unsigned int shift, unsigned int nbits)
450 {
451 	if (small_const_nbits(nbits))
452 		*dst = (*src << shift) & BITMAP_LAST_WORD_MASK(nbits);
453 	else
454 		__bitmap_shift_left(dst, src, shift, nbits);
455 }
456 
bitmap_replace(unsigned long * dst,const unsigned long * old,const unsigned long * new,const unsigned long * mask,unsigned int nbits)457 static inline void bitmap_replace(unsigned long *dst,
458 				  const unsigned long *old,
459 				  const unsigned long *new,
460 				  const unsigned long *mask,
461 				  unsigned int nbits)
462 {
463 	if (small_const_nbits(nbits))
464 		*dst = (*old & ~(*mask)) | (*new & *mask);
465 	else
466 		__bitmap_replace(dst, old, new, mask, nbits);
467 }
468 
bitmap_next_clear_region(unsigned long * bitmap,unsigned int * rs,unsigned int * re,unsigned int end)469 static inline void bitmap_next_clear_region(unsigned long *bitmap,
470 					    unsigned int *rs, unsigned int *re,
471 					    unsigned int end)
472 {
473 	*rs = find_next_zero_bit(bitmap, end, *rs);
474 	*re = find_next_bit(bitmap, end, *rs + 1);
475 }
476 
bitmap_next_set_region(unsigned long * bitmap,unsigned int * rs,unsigned int * re,unsigned int end)477 static inline void bitmap_next_set_region(unsigned long *bitmap,
478 					  unsigned int *rs, unsigned int *re,
479 					  unsigned int end)
480 {
481 	*rs = find_next_bit(bitmap, end, *rs);
482 	*re = find_next_zero_bit(bitmap, end, *rs + 1);
483 }
484 
485 /*
486  * Bitmap region iterators.  Iterates over the bitmap between [@start, @end).
487  * @rs and @re should be integer variables and will be set to start and end
488  * index of the current clear or set region.
489  */
490 #define bitmap_for_each_clear_region(bitmap, rs, re, start, end)	     \
491 	for ((rs) = (start),						     \
492 	     bitmap_next_clear_region((bitmap), &(rs), &(re), (end));	     \
493 	     (rs) < (re);						     \
494 	     (rs) = (re) + 1,						     \
495 	     bitmap_next_clear_region((bitmap), &(rs), &(re), (end)))
496 
497 #define bitmap_for_each_set_region(bitmap, rs, re, start, end)		     \
498 	for ((rs) = (start),						     \
499 	     bitmap_next_set_region((bitmap), &(rs), &(re), (end));	     \
500 	     (rs) < (re);						     \
501 	     (rs) = (re) + 1,						     \
502 	     bitmap_next_set_region((bitmap), &(rs), &(re), (end)))
503 
504 /**
505  * BITMAP_FROM_U64() - Represent u64 value in the format suitable for bitmap.
506  * @n: u64 value
507  *
508  * Linux bitmaps are internally arrays of unsigned longs, i.e. 32-bit
509  * integers in 32-bit environment, and 64-bit integers in 64-bit one.
510  *
511  * There are four combinations of endianness and length of the word in linux
512  * ABIs: LE64, BE64, LE32 and BE32.
513  *
514  * On 64-bit kernels 64-bit LE and BE numbers are naturally ordered in
515  * bitmaps and therefore don't require any special handling.
516  *
517  * On 32-bit kernels 32-bit LE ABI orders lo word of 64-bit number in memory
518  * prior to hi, and 32-bit BE orders hi word prior to lo. The bitmap on the
519  * other hand is represented as an array of 32-bit words and the position of
520  * bit N may therefore be calculated as: word #(N/32) and bit #(N%32) in that
521  * word.  For example, bit #42 is located at 10th position of 2nd word.
522  * It matches 32-bit LE ABI, and we can simply let the compiler store 64-bit
523  * values in memory as it usually does. But for BE we need to swap hi and lo
524  * words manually.
525  *
526  * With all that, the macro BITMAP_FROM_U64() does explicit reordering of hi and
527  * lo parts of u64.  For LE32 it does nothing, and for BE environment it swaps
528  * hi and lo words, as is expected by bitmap.
529  */
530 #if __BITS_PER_LONG == 64
531 #define BITMAP_FROM_U64(n) (n)
532 #else
533 #define BITMAP_FROM_U64(n) ((unsigned long) ((u64)(n) & ULONG_MAX)), \
534 				((unsigned long) ((u64)(n) >> 32))
535 #endif
536 
537 /**
538  * bitmap_from_u64 - Check and swap words within u64.
539  *  @mask: source bitmap
540  *  @dst:  destination bitmap
541  *
542  * In 32-bit Big Endian kernel, when using ``(u32 *)(&val)[*]``
543  * to read u64 mask, we will get the wrong word.
544  * That is ``(u32 *)(&val)[0]`` gets the upper 32 bits,
545  * but we expect the lower 32-bits of u64.
546  */
bitmap_from_u64(unsigned long * dst,u64 mask)547 static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
548 {
549 	dst[0] = mask & ULONG_MAX;
550 
551 	if (sizeof(mask) > sizeof(unsigned long))
552 		dst[1] = mask >> 32;
553 }
554 
555 /**
556  * bitmap_get_value8 - get an 8-bit value within a memory region
557  * @map: address to the bitmap memory region
558  * @start: bit offset of the 8-bit value; must be a multiple of 8
559  *
560  * Returns the 8-bit value located at the @start bit offset within the @src
561  * memory region.
562  */
bitmap_get_value8(const unsigned long * map,unsigned long start)563 static inline unsigned long bitmap_get_value8(const unsigned long *map,
564 					      unsigned long start)
565 {
566 	const size_t index = BIT_WORD(start);
567 	const unsigned long offset = start % BITS_PER_LONG;
568 
569 	return (map[index] >> offset) & 0xFF;
570 }
571 
572 /**
573  * bitmap_set_value8 - set an 8-bit value within a memory region
574  * @map: address to the bitmap memory region
575  * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
576  * @start: bit offset of the 8-bit value; must be a multiple of 8
577  */
bitmap_set_value8(unsigned long * map,unsigned long value,unsigned long start)578 static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
579 				     unsigned long start)
580 {
581 	const size_t index = BIT_WORD(start);
582 	const unsigned long offset = start % BITS_PER_LONG;
583 
584 	map[index] &= ~(0xFFUL << offset);
585 	map[index] |= value << offset;
586 }
587 
588 #endif /* __ASSEMBLY__ */
589 
590 #endif /* __LINUX_BITMAP_H */
591