1 // SPDX-License-Identifier: GPL-2.0-only
4 * Helper functions for bitmap.h.
6 #include <linux/export.h>
7 #include <linux/thread_info.h>
8 #include <linux/ctype.h>
9 #include <linux/errno.h>
10 #include <linux/bitmap.h>
11 #include <linux/bitops.h>
12 #include <linux/bug.h>
13 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/uaccess.h>
24 * DOC: bitmap introduction
26 * bitmaps provide an array of bits, implemented using an an
27 * array of unsigned longs. The number of valid bits in a
28 * given bitmap does _not_ need to be an exact multiple of
31 * The possible unused bits in the last, partially used word
32 * of a bitmap are 'don't care'. The implementation makes
33 * no particular effort to keep them zero. It ensures that
34 * their value will not affect the results of any operation.
35 * The bitmap operations that return Boolean (bitmap_empty,
36 * for example) or scalar (bitmap_weight, for example) results
37 * carefully filter out these unused bits from impacting their
40 * The byte ordering of bitmaps is more natural on little
41 * endian architectures. See the big-endian headers
42 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
43 * for the best explanations of this ordering.
46 int __bitmap_equal(const unsigned long *bitmap1
,
47 const unsigned long *bitmap2
, unsigned int bits
)
49 unsigned int k
, lim
= bits
/BITS_PER_LONG
;
50 for (k
= 0; k
< lim
; ++k
)
51 if (bitmap1
[k
] != bitmap2
[k
])
54 if (bits
% BITS_PER_LONG
)
55 if ((bitmap1
[k
] ^ bitmap2
[k
]) & BITMAP_LAST_WORD_MASK(bits
))
60 EXPORT_SYMBOL(__bitmap_equal
);
62 bool __bitmap_or_equal(const unsigned long *bitmap1
,
63 const unsigned long *bitmap2
,
64 const unsigned long *bitmap3
,
67 unsigned int k
, lim
= bits
/ BITS_PER_LONG
;
70 for (k
= 0; k
< lim
; ++k
) {
71 if ((bitmap1
[k
] | bitmap2
[k
]) != bitmap3
[k
])
75 if (!(bits
% BITS_PER_LONG
))
78 tmp
= (bitmap1
[k
] | bitmap2
[k
]) ^ bitmap3
[k
];
79 return (tmp
& BITMAP_LAST_WORD_MASK(bits
)) == 0;
82 void __bitmap_complement(unsigned long *dst
, const unsigned long *src
, unsigned int bits
)
84 unsigned int k
, lim
= BITS_TO_LONGS(bits
);
85 for (k
= 0; k
< lim
; ++k
)
88 EXPORT_SYMBOL(__bitmap_complement
);
91 * __bitmap_shift_right - logical right shift of the bits in a bitmap
92 * @dst : destination bitmap
93 * @src : source bitmap
94 * @shift : shift by this many bits
95 * @nbits : bitmap size, in bits
97 * Shifting right (dividing) means moving bits in the MS -> LS bit
98 * direction. Zeros are fed into the vacated MS positions and the
99 * LS bits shifted off the bottom are lost.
101 void __bitmap_shift_right(unsigned long *dst
, const unsigned long *src
,
102 unsigned shift
, unsigned nbits
)
104 unsigned k
, lim
= BITS_TO_LONGS(nbits
);
105 unsigned off
= shift
/BITS_PER_LONG
, rem
= shift
% BITS_PER_LONG
;
106 unsigned long mask
= BITMAP_LAST_WORD_MASK(nbits
);
107 for (k
= 0; off
+ k
< lim
; ++k
) {
108 unsigned long upper
, lower
;
111 * If shift is not word aligned, take lower rem bits of
112 * word above and make them the top rem bits of result.
114 if (!rem
|| off
+ k
+ 1 >= lim
)
117 upper
= src
[off
+ k
+ 1];
118 if (off
+ k
+ 1 == lim
- 1)
120 upper
<<= (BITS_PER_LONG
- rem
);
122 lower
= src
[off
+ k
];
123 if (off
+ k
== lim
- 1)
126 dst
[k
] = lower
| upper
;
129 memset(&dst
[lim
- off
], 0, off
*sizeof(unsigned long));
131 EXPORT_SYMBOL(__bitmap_shift_right
);
135 * __bitmap_shift_left - logical left shift of the bits in a bitmap
136 * @dst : destination bitmap
137 * @src : source bitmap
138 * @shift : shift by this many bits
139 * @nbits : bitmap size, in bits
141 * Shifting left (multiplying) means moving bits in the LS -> MS
142 * direction. Zeros are fed into the vacated LS bit positions
143 * and those MS bits shifted off the top are lost.
146 void __bitmap_shift_left(unsigned long *dst
, const unsigned long *src
,
147 unsigned int shift
, unsigned int nbits
)
150 unsigned int lim
= BITS_TO_LONGS(nbits
);
151 unsigned int off
= shift
/BITS_PER_LONG
, rem
= shift
% BITS_PER_LONG
;
152 for (k
= lim
- off
- 1; k
>= 0; --k
) {
153 unsigned long upper
, lower
;
156 * If shift is not word aligned, take upper rem bits of
157 * word below and make them the bottom rem bits of result.
160 lower
= src
[k
- 1] >> (BITS_PER_LONG
- rem
);
163 upper
= src
[k
] << rem
;
164 dst
[k
+ off
] = lower
| upper
;
167 memset(dst
, 0, off
*sizeof(unsigned long));
169 EXPORT_SYMBOL(__bitmap_shift_left
);
171 int __bitmap_and(unsigned long *dst
, const unsigned long *bitmap1
,
172 const unsigned long *bitmap2
, unsigned int bits
)
175 unsigned int lim
= bits
/BITS_PER_LONG
;
176 unsigned long result
= 0;
178 for (k
= 0; k
< lim
; k
++)
179 result
|= (dst
[k
] = bitmap1
[k
] & bitmap2
[k
]);
180 if (bits
% BITS_PER_LONG
)
181 result
|= (dst
[k
] = bitmap1
[k
] & bitmap2
[k
] &
182 BITMAP_LAST_WORD_MASK(bits
));
185 EXPORT_SYMBOL(__bitmap_and
);
187 void __bitmap_or(unsigned long *dst
, const unsigned long *bitmap1
,
188 const unsigned long *bitmap2
, unsigned int bits
)
191 unsigned int nr
= BITS_TO_LONGS(bits
);
193 for (k
= 0; k
< nr
; k
++)
194 dst
[k
] = bitmap1
[k
] | bitmap2
[k
];
196 EXPORT_SYMBOL(__bitmap_or
);
198 void __bitmap_xor(unsigned long *dst
, const unsigned long *bitmap1
,
199 const unsigned long *bitmap2
, unsigned int bits
)
202 unsigned int nr
= BITS_TO_LONGS(bits
);
204 for (k
= 0; k
< nr
; k
++)
205 dst
[k
] = bitmap1
[k
] ^ bitmap2
[k
];
207 EXPORT_SYMBOL(__bitmap_xor
);
209 int __bitmap_andnot(unsigned long *dst
, const unsigned long *bitmap1
,
210 const unsigned long *bitmap2
, unsigned int bits
)
213 unsigned int lim
= bits
/BITS_PER_LONG
;
214 unsigned long result
= 0;
216 for (k
= 0; k
< lim
; k
++)
217 result
|= (dst
[k
] = bitmap1
[k
] & ~bitmap2
[k
]);
218 if (bits
% BITS_PER_LONG
)
219 result
|= (dst
[k
] = bitmap1
[k
] & ~bitmap2
[k
] &
220 BITMAP_LAST_WORD_MASK(bits
));
223 EXPORT_SYMBOL(__bitmap_andnot
);
225 void __bitmap_replace(unsigned long *dst
,
226 const unsigned long *old
, const unsigned long *new,
227 const unsigned long *mask
, unsigned int nbits
)
230 unsigned int nr
= BITS_TO_LONGS(nbits
);
232 for (k
= 0; k
< nr
; k
++)
233 dst
[k
] = (old
[k
] & ~mask
[k
]) | (new[k
] & mask
[k
]);
235 EXPORT_SYMBOL(__bitmap_replace
);
237 int __bitmap_intersects(const unsigned long *bitmap1
,
238 const unsigned long *bitmap2
, unsigned int bits
)
240 unsigned int k
, lim
= bits
/BITS_PER_LONG
;
241 for (k
= 0; k
< lim
; ++k
)
242 if (bitmap1
[k
] & bitmap2
[k
])
245 if (bits
% BITS_PER_LONG
)
246 if ((bitmap1
[k
] & bitmap2
[k
]) & BITMAP_LAST_WORD_MASK(bits
))
250 EXPORT_SYMBOL(__bitmap_intersects
);
252 int __bitmap_subset(const unsigned long *bitmap1
,
253 const unsigned long *bitmap2
, unsigned int bits
)
255 unsigned int k
, lim
= bits
/BITS_PER_LONG
;
256 for (k
= 0; k
< lim
; ++k
)
257 if (bitmap1
[k
] & ~bitmap2
[k
])
260 if (bits
% BITS_PER_LONG
)
261 if ((bitmap1
[k
] & ~bitmap2
[k
]) & BITMAP_LAST_WORD_MASK(bits
))
265 EXPORT_SYMBOL(__bitmap_subset
);
267 int __bitmap_weight(const unsigned long *bitmap
, unsigned int bits
)
269 unsigned int k
, lim
= bits
/BITS_PER_LONG
;
272 for (k
= 0; k
< lim
; k
++)
273 w
+= hweight_long(bitmap
[k
]);
275 if (bits
% BITS_PER_LONG
)
276 w
+= hweight_long(bitmap
[k
] & BITMAP_LAST_WORD_MASK(bits
));
280 EXPORT_SYMBOL(__bitmap_weight
);
282 void __bitmap_set(unsigned long *map
, unsigned int start
, int len
)
284 unsigned long *p
= map
+ BIT_WORD(start
);
285 const unsigned int size
= start
+ len
;
286 int bits_to_set
= BITS_PER_LONG
- (start
% BITS_PER_LONG
);
287 unsigned long mask_to_set
= BITMAP_FIRST_WORD_MASK(start
);
289 while (len
- bits_to_set
>= 0) {
292 bits_to_set
= BITS_PER_LONG
;
297 mask_to_set
&= BITMAP_LAST_WORD_MASK(size
);
301 EXPORT_SYMBOL(__bitmap_set
);
303 void __bitmap_clear(unsigned long *map
, unsigned int start
, int len
)
305 unsigned long *p
= map
+ BIT_WORD(start
);
306 const unsigned int size
= start
+ len
;
307 int bits_to_clear
= BITS_PER_LONG
- (start
% BITS_PER_LONG
);
308 unsigned long mask_to_clear
= BITMAP_FIRST_WORD_MASK(start
);
310 while (len
- bits_to_clear
>= 0) {
311 *p
&= ~mask_to_clear
;
312 len
-= bits_to_clear
;
313 bits_to_clear
= BITS_PER_LONG
;
314 mask_to_clear
= ~0UL;
318 mask_to_clear
&= BITMAP_LAST_WORD_MASK(size
);
319 *p
&= ~mask_to_clear
;
322 EXPORT_SYMBOL(__bitmap_clear
);
325 * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
326 * @map: The address to base the search on
327 * @size: The bitmap size in bits
328 * @start: The bitnumber to start searching at
329 * @nr: The number of zeroed bits we're looking for
330 * @align_mask: Alignment mask for zero area
331 * @align_offset: Alignment offset for zero area.
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 plus @align_offset
335 * is multiple of that power of 2.
337 unsigned long bitmap_find_next_zero_area_off(unsigned long *map
,
341 unsigned long align_mask
,
342 unsigned long align_offset
)
344 unsigned long index
, end
, i
;
346 index
= find_next_zero_bit(map
, size
, start
);
348 /* Align allocation */
349 index
= __ALIGN_MASK(index
+ align_offset
, align_mask
) - align_offset
;
354 i
= find_next_bit(map
, end
, index
);
361 EXPORT_SYMBOL(bitmap_find_next_zero_area_off
);
364 * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
365 * second version by Paul Jackson, third by Joe Korty.
369 #define nbits_to_hold_value(val) fls(val)
370 #define BASEDEC 10 /* fancier cpuset lists input in decimal */
373 * __bitmap_parse - convert an ASCII hex string into a bitmap.
374 * @buf: pointer to buffer containing string.
375 * @buflen: buffer size in bytes. If string is smaller than this
376 * then it must be terminated with a \0.
377 * @is_user: location of buffer, 0 indicates kernel space
378 * @maskp: pointer to bitmap array that will contain result.
379 * @nmaskbits: size of bitmap, in bits.
381 * Commas group hex digits into chunks. Each chunk defines exactly 32
382 * bits of the resultant bitmask. No chunk may specify a value larger
383 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
384 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
385 * characters and for grouping errors such as "1,,5", ",44", "," and "".
386 * Leading and trailing whitespace accepted, but not embedded whitespace.
388 int __bitmap_parse(const char *buf
, unsigned int buflen
,
389 int is_user
, unsigned long *maskp
,
392 int c
, old_c
, totaldigits
, ndigits
, nchunks
, nbits
;
394 const char __user __force
*ubuf
= (const char __user __force
*)buf
;
396 bitmap_zero(maskp
, nmaskbits
);
398 nchunks
= nbits
= totaldigits
= c
= 0;
401 ndigits
= totaldigits
;
403 /* Get the next chunk of the bitmap */
407 if (__get_user(c
, ubuf
++))
417 * If the last character was a space and the current
418 * character isn't '\0', we've got embedded whitespace.
419 * This is a no-no, so throw an error.
421 if (totaldigits
&& c
&& isspace(old_c
))
424 /* A '\0' or a ',' signal the end of the chunk */
425 if (c
== '\0' || c
== ',')
432 * Make sure there are at least 4 free bits in 'chunk'.
433 * If not, this hexdigit will overflow 'chunk', so
436 if (chunk
& ~((1UL << (CHUNKSZ
- 4)) - 1))
439 chunk
= (chunk
<< 4) | hex_to_bin(c
);
442 if (ndigits
== totaldigits
)
444 if (nchunks
== 0 && chunk
== 0)
447 __bitmap_shift_left(maskp
, maskp
, CHUNKSZ
, nmaskbits
);
450 nbits
+= (nchunks
== 1) ? nbits_to_hold_value(chunk
) : CHUNKSZ
;
451 if (nbits
> nmaskbits
)
453 } while (buflen
&& c
== ',');
457 EXPORT_SYMBOL(__bitmap_parse
);
460 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
462 * @ubuf: pointer to user buffer containing string.
463 * @ulen: buffer size in bytes. If string is smaller than this
464 * then it must be terminated with a \0.
465 * @maskp: pointer to bitmap array that will contain result.
466 * @nmaskbits: size of bitmap, in bits.
468 * Wrapper for __bitmap_parse(), providing it with user buffer.
470 * We cannot have this as an inline function in bitmap.h because it needs
471 * linux/uaccess.h to get the access_ok() declaration and this causes
472 * cyclic dependencies.
474 int bitmap_parse_user(const char __user
*ubuf
,
475 unsigned int ulen
, unsigned long *maskp
,
478 if (!access_ok(ubuf
, ulen
))
480 return __bitmap_parse((const char __force
*)ubuf
,
481 ulen
, 1, maskp
, nmaskbits
);
484 EXPORT_SYMBOL(bitmap_parse_user
);
487 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
488 * @list: indicates whether the bitmap must be list
489 * @buf: page aligned buffer into which string is placed
490 * @maskp: pointer to bitmap to convert
491 * @nmaskbits: size of bitmap, in bits
493 * Output format is a comma-separated list of decimal numbers and
494 * ranges if list is specified or hex digits grouped into comma-separated
495 * sets of 8 digits/set. Returns the number of characters written to buf.
497 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
498 * area and that sufficient storage remains at @buf to accommodate the
499 * bitmap_print_to_pagebuf() output. Returns the number of characters
500 * actually printed to @buf, excluding terminating '\0'.
502 int bitmap_print_to_pagebuf(bool list
, char *buf
, const unsigned long *maskp
,
505 ptrdiff_t len
= PAGE_SIZE
- offset_in_page(buf
);
507 return list
? scnprintf(buf
, len
, "%*pbl\n", nmaskbits
, maskp
) :
508 scnprintf(buf
, len
, "%*pb\n", nmaskbits
, maskp
);
510 EXPORT_SYMBOL(bitmap_print_to_pagebuf
);
513 * Region 9-38:4/10 describes the following bitmap structure:
515 * .........****......****......****......
517 * start off group_len end
522 unsigned int group_len
;
526 static int bitmap_set_region(const struct region
*r
,
527 unsigned long *bitmap
, int nbits
)
534 for (start
= r
->start
; start
<= r
->end
; start
+= r
->group_len
)
535 bitmap_set(bitmap
, start
, min(r
->end
- start
+ 1, r
->off
));
540 static int bitmap_check_region(const struct region
*r
)
542 if (r
->start
> r
->end
|| r
->group_len
== 0 || r
->off
> r
->group_len
)
548 static const char *bitmap_getnum(const char *str
, unsigned int *num
)
550 unsigned long long n
;
553 len
= _parse_integer(str
, 10, &n
);
555 return ERR_PTR(-EINVAL
);
556 if (len
& KSTRTOX_OVERFLOW
|| n
!= (unsigned int)n
)
557 return ERR_PTR(-EOVERFLOW
);
563 static inline bool end_of_str(char c
)
565 return c
== '\0' || c
== '\n';
568 static inline bool __end_of_region(char c
)
570 return isspace(c
) || c
== ',';
573 static inline bool end_of_region(char c
)
575 return __end_of_region(c
) || end_of_str(c
);
579 * The format allows commas and whitespases at the beginning
582 static const char *bitmap_find_region(const char *str
)
584 while (__end_of_region(*str
))
587 return end_of_str(*str
) ? NULL
: str
;
590 static const char *bitmap_parse_region(const char *str
, struct region
*r
)
592 str
= bitmap_getnum(str
, &r
->start
);
596 if (end_of_region(*str
))
600 return ERR_PTR(-EINVAL
);
602 str
= bitmap_getnum(str
+ 1, &r
->end
);
606 if (end_of_region(*str
))
610 return ERR_PTR(-EINVAL
);
612 str
= bitmap_getnum(str
+ 1, &r
->off
);
617 return ERR_PTR(-EINVAL
);
619 return bitmap_getnum(str
+ 1, &r
->group_len
);
625 r
->group_len
= r
->end
+ 1;
627 return end_of_str(*str
) ? NULL
: str
;
631 * bitmap_parselist - convert list format ASCII string to bitmap
632 * @buf: read user string from this buffer; must be terminated
634 * @maskp: write resulting mask here
635 * @nmaskbits: number of bits in mask to be written
637 * Input format is a comma-separated list of decimal numbers and
638 * ranges. Consecutively set bits are shown as two hyphen-separated
639 * decimal numbers, the smallest and largest bit numbers set in
641 * Optionally each range can be postfixed to denote that only parts of it
642 * should be set. The range will divided to groups of specific size.
643 * From each group will be used only defined amount of bits.
644 * Syntax: range:used_size/group_size
645 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
647 * Returns: 0 on success, -errno on invalid input strings. Error values:
649 * - ``-EINVAL``: wrong region format
650 * - ``-EINVAL``: invalid character in string
651 * - ``-ERANGE``: bit number specified too large for mask
652 * - ``-EOVERFLOW``: integer overflow in the input parameters
654 int bitmap_parselist(const char *buf
, unsigned long *maskp
, int nmaskbits
)
659 bitmap_zero(maskp
, nmaskbits
);
662 buf
= bitmap_find_region(buf
);
666 buf
= bitmap_parse_region(buf
, &r
);
670 ret
= bitmap_check_region(&r
);
674 ret
= bitmap_set_region(&r
, maskp
, nmaskbits
);
681 EXPORT_SYMBOL(bitmap_parselist
);
685 * bitmap_parselist_user()
687 * @ubuf: pointer to user buffer containing string.
688 * @ulen: buffer size in bytes. If string is smaller than this
689 * then it must be terminated with a \0.
690 * @maskp: pointer to bitmap array that will contain result.
691 * @nmaskbits: size of bitmap, in bits.
693 * Wrapper for bitmap_parselist(), providing it with user buffer.
695 int bitmap_parselist_user(const char __user
*ubuf
,
696 unsigned int ulen
, unsigned long *maskp
,
702 buf
= memdup_user_nul(ubuf
, ulen
);
706 ret
= bitmap_parselist(buf
, maskp
, nmaskbits
);
711 EXPORT_SYMBOL(bitmap_parselist_user
);
716 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
717 * @buf: pointer to a bitmap
718 * @pos: a bit position in @buf (0 <= @pos < @nbits)
719 * @nbits: number of valid bit positions in @buf
721 * Map the bit at position @pos in @buf (of length @nbits) to the
722 * ordinal of which set bit it is. If it is not set or if @pos
723 * is not a valid bit position, map to -1.
725 * If for example, just bits 4 through 7 are set in @buf, then @pos
726 * values 4 through 7 will get mapped to 0 through 3, respectively,
727 * and other @pos values will get mapped to -1. When @pos value 7
728 * gets mapped to (returns) @ord value 3 in this example, that means
729 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
731 * The bit positions 0 through @bits are valid positions in @buf.
733 static int bitmap_pos_to_ord(const unsigned long *buf
, unsigned int pos
, unsigned int nbits
)
735 if (pos
>= nbits
|| !test_bit(pos
, buf
))
738 return __bitmap_weight(buf
, pos
);
742 * bitmap_ord_to_pos - find position of n-th set bit in bitmap
743 * @buf: pointer to bitmap
744 * @ord: ordinal bit position (n-th set bit, n >= 0)
745 * @nbits: number of valid bit positions in @buf
747 * Map the ordinal offset of bit @ord in @buf to its position in @buf.
748 * Value of @ord should be in range 0 <= @ord < weight(buf). If @ord
749 * >= weight(buf), returns @nbits.
751 * If for example, just bits 4 through 7 are set in @buf, then @ord
752 * values 0 through 3 will get mapped to 4 through 7, respectively,
753 * and all other @ord values returns @nbits. When @ord value 3
754 * gets mapped to (returns) @pos value 7 in this example, that means
755 * that the 3rd set bit (starting with 0th) is at position 7 in @buf.
757 * The bit positions 0 through @nbits-1 are valid positions in @buf.
759 unsigned int bitmap_ord_to_pos(const unsigned long *buf
, unsigned int ord
, unsigned int nbits
)
763 for (pos
= find_first_bit(buf
, nbits
);
765 pos
= find_next_bit(buf
, nbits
, pos
+ 1))
772 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
773 * @dst: remapped result
774 * @src: subset to be remapped
775 * @old: defines domain of map
776 * @new: defines range of map
777 * @nbits: number of bits in each of these bitmaps
779 * Let @old and @new define a mapping of bit positions, such that
780 * whatever position is held by the n-th set bit in @old is mapped
781 * to the n-th set bit in @new. In the more general case, allowing
782 * for the possibility that the weight 'w' of @new is less than the
783 * weight of @old, map the position of the n-th set bit in @old to
784 * the position of the m-th set bit in @new, where m == n % w.
786 * If either of the @old and @new bitmaps are empty, or if @src and
787 * @dst point to the same location, then this routine copies @src
790 * The positions of unset bits in @old are mapped to themselves
791 * (the identify map).
793 * Apply the above specified mapping to @src, placing the result in
794 * @dst, clearing any bits previously set in @dst.
796 * For example, lets say that @old has bits 4 through 7 set, and
797 * @new has bits 12 through 15 set. This defines the mapping of bit
798 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
799 * bit positions unchanged. So if say @src comes into this routine
800 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
803 void bitmap_remap(unsigned long *dst
, const unsigned long *src
,
804 const unsigned long *old
, const unsigned long *new,
807 unsigned int oldbit
, w
;
809 if (dst
== src
) /* following doesn't handle inplace remaps */
811 bitmap_zero(dst
, nbits
);
813 w
= bitmap_weight(new, nbits
);
814 for_each_set_bit(oldbit
, src
, nbits
) {
815 int n
= bitmap_pos_to_ord(old
, oldbit
, nbits
);
818 set_bit(oldbit
, dst
); /* identity map */
820 set_bit(bitmap_ord_to_pos(new, n
% w
, nbits
), dst
);
825 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
826 * @oldbit: bit position to be mapped
827 * @old: defines domain of map
828 * @new: defines range of map
829 * @bits: number of bits in each of these bitmaps
831 * Let @old and @new define a mapping of bit positions, such that
832 * whatever position is held by the n-th set bit in @old is mapped
833 * to the n-th set bit in @new. In the more general case, allowing
834 * for the possibility that the weight 'w' of @new is less than the
835 * weight of @old, map the position of the n-th set bit in @old to
836 * the position of the m-th set bit in @new, where m == n % w.
838 * The positions of unset bits in @old are mapped to themselves
839 * (the identify map).
841 * Apply the above specified mapping to bit position @oldbit, returning
842 * the new bit position.
844 * For example, lets say that @old has bits 4 through 7 set, and
845 * @new has bits 12 through 15 set. This defines the mapping of bit
846 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
847 * bit positions unchanged. So if say @oldbit is 5, then this routine
850 int bitmap_bitremap(int oldbit
, const unsigned long *old
,
851 const unsigned long *new, int bits
)
853 int w
= bitmap_weight(new, bits
);
854 int n
= bitmap_pos_to_ord(old
, oldbit
, bits
);
858 return bitmap_ord_to_pos(new, n
% w
, bits
);
862 * bitmap_onto - translate one bitmap relative to another
863 * @dst: resulting translated bitmap
864 * @orig: original untranslated bitmap
865 * @relmap: bitmap relative to which translated
866 * @bits: number of bits in each of these bitmaps
868 * Set the n-th bit of @dst iff there exists some m such that the
869 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
870 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
871 * (If you understood the previous sentence the first time your
872 * read it, you're overqualified for your current job.)
874 * In other words, @orig is mapped onto (surjectively) @dst,
875 * using the map { <n, m> | the n-th bit of @relmap is the
876 * m-th set bit of @relmap }.
878 * Any set bits in @orig above bit number W, where W is the
879 * weight of (number of set bits in) @relmap are mapped nowhere.
880 * In particular, if for all bits m set in @orig, m >= W, then
881 * @dst will end up empty. In situations where the possibility
882 * of such an empty result is not desired, one way to avoid it is
883 * to use the bitmap_fold() operator, below, to first fold the
884 * @orig bitmap over itself so that all its set bits x are in the
885 * range 0 <= x < W. The bitmap_fold() operator does this by
886 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
888 * Example [1] for bitmap_onto():
889 * Let's say @relmap has bits 30-39 set, and @orig has bits
890 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
891 * @dst will have bits 31, 33, 35, 37 and 39 set.
893 * When bit 0 is set in @orig, it means turn on the bit in
894 * @dst corresponding to whatever is the first bit (if any)
895 * that is turned on in @relmap. Since bit 0 was off in the
896 * above example, we leave off that bit (bit 30) in @dst.
898 * When bit 1 is set in @orig (as in the above example), it
899 * means turn on the bit in @dst corresponding to whatever
900 * is the second bit that is turned on in @relmap. The second
901 * bit in @relmap that was turned on in the above example was
902 * bit 31, so we turned on bit 31 in @dst.
904 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
905 * because they were the 4th, 6th, 8th and 10th set bits
906 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
907 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
909 * When bit 11 is set in @orig, it means turn on the bit in
910 * @dst corresponding to whatever is the twelfth bit that is
911 * turned on in @relmap. In the above example, there were
912 * only ten bits turned on in @relmap (30..39), so that bit
913 * 11 was set in @orig had no affect on @dst.
915 * Example [2] for bitmap_fold() + bitmap_onto():
916 * Let's say @relmap has these ten bits set::
918 * 40 41 42 43 45 48 53 61 74 95
920 * (for the curious, that's 40 plus the first ten terms of the
921 * Fibonacci sequence.)
923 * Further lets say we use the following code, invoking
924 * bitmap_fold() then bitmap_onto, as suggested above to
925 * avoid the possibility of an empty @dst result::
927 * unsigned long *tmp; // a temporary bitmap's bits
929 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
930 * bitmap_onto(dst, tmp, relmap, bits);
932 * Then this table shows what various values of @dst would be, for
933 * various @orig's. I list the zero-based positions of each set bit.
934 * The tmp column shows the intermediate result, as computed by
935 * using bitmap_fold() to fold the @orig bitmap modulo ten
936 * (the weight of @relmap):
938 * =============== ============== =================
944 * 1 3 5 7 1 3 5 7 41 43 48 61
945 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
946 * 0 9 18 27 0 9 8 7 40 61 74 95
948 * 0 11 22 33 0 1 2 3 40 41 42 43
949 * 0 12 24 36 0 2 4 6 40 42 45 53
950 * 78 102 211 1 2 8 41 42 74 [#f1]_
951 * =============== ============== =================
955 * For these marked lines, if we hadn't first done bitmap_fold()
956 * into tmp, then the @dst result would have been empty.
958 * If either of @orig or @relmap is empty (no set bits), then @dst
959 * will be returned empty.
961 * If (as explained above) the only set bits in @orig are in positions
962 * m where m >= W, (where W is the weight of @relmap) then @dst will
963 * once again be returned empty.
965 * All bits in @dst not set by the above rule are cleared.
967 void bitmap_onto(unsigned long *dst
, const unsigned long *orig
,
968 const unsigned long *relmap
, unsigned int bits
)
970 unsigned int n
, m
; /* same meaning as in above comment */
972 if (dst
== orig
) /* following doesn't handle inplace mappings */
974 bitmap_zero(dst
, bits
);
977 * The following code is a more efficient, but less
978 * obvious, equivalent to the loop:
979 * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
980 * n = bitmap_ord_to_pos(orig, m, bits);
981 * if (test_bit(m, orig))
987 for_each_set_bit(n
, relmap
, bits
) {
988 /* m == bitmap_pos_to_ord(relmap, n, bits) */
989 if (test_bit(m
, orig
))
996 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
997 * @dst: resulting smaller bitmap
998 * @orig: original larger bitmap
999 * @sz: specified size
1000 * @nbits: number of bits in each of these bitmaps
1002 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1003 * Clear all other bits in @dst. See further the comment and
1004 * Example [2] for bitmap_onto() for why and how to use this.
1006 void bitmap_fold(unsigned long *dst
, const unsigned long *orig
,
1007 unsigned int sz
, unsigned int nbits
)
1009 unsigned int oldbit
;
1011 if (dst
== orig
) /* following doesn't handle inplace mappings */
1013 bitmap_zero(dst
, nbits
);
1015 for_each_set_bit(oldbit
, orig
, nbits
)
1016 set_bit(oldbit
% sz
, dst
);
1018 #endif /* CONFIG_NUMA */
1021 * Common code for bitmap_*_region() routines.
1022 * bitmap: array of unsigned longs corresponding to the bitmap
1023 * pos: the beginning of the region
1024 * order: region size (log base 2 of number of bits)
1025 * reg_op: operation(s) to perform on that region of bitmap
1027 * Can set, verify and/or release a region of bits in a bitmap,
1028 * depending on which combination of REG_OP_* flag bits is set.
1030 * A region of a bitmap is a sequence of bits in the bitmap, of
1031 * some size '1 << order' (a power of two), aligned to that same
1032 * '1 << order' power of two.
1034 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1035 * Returns 0 in all other cases and reg_ops.
1039 REG_OP_ISFREE
, /* true if region is all zero bits */
1040 REG_OP_ALLOC
, /* set all bits in region */
1041 REG_OP_RELEASE
, /* clear all bits in region */
1044 static int __reg_op(unsigned long *bitmap
, unsigned int pos
, int order
, int reg_op
)
1046 int nbits_reg
; /* number of bits in region */
1047 int index
; /* index first long of region in bitmap */
1048 int offset
; /* bit offset region in bitmap[index] */
1049 int nlongs_reg
; /* num longs spanned by region in bitmap */
1050 int nbitsinlong
; /* num bits of region in each spanned long */
1051 unsigned long mask
; /* bitmask for one long of region */
1052 int i
; /* scans bitmap by longs */
1053 int ret
= 0; /* return value */
1056 * Either nlongs_reg == 1 (for small orders that fit in one long)
1057 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1059 nbits_reg
= 1 << order
;
1060 index
= pos
/ BITS_PER_LONG
;
1061 offset
= pos
- (index
* BITS_PER_LONG
);
1062 nlongs_reg
= BITS_TO_LONGS(nbits_reg
);
1063 nbitsinlong
= min(nbits_reg
, BITS_PER_LONG
);
1066 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1067 * overflows if nbitsinlong == BITS_PER_LONG.
1069 mask
= (1UL << (nbitsinlong
- 1));
1075 for (i
= 0; i
< nlongs_reg
; i
++) {
1076 if (bitmap
[index
+ i
] & mask
)
1079 ret
= 1; /* all bits in region free (zero) */
1083 for (i
= 0; i
< nlongs_reg
; i
++)
1084 bitmap
[index
+ i
] |= mask
;
1087 case REG_OP_RELEASE
:
1088 for (i
= 0; i
< nlongs_reg
; i
++)
1089 bitmap
[index
+ i
] &= ~mask
;
1097 * bitmap_find_free_region - find a contiguous aligned mem region
1098 * @bitmap: array of unsigned longs corresponding to the bitmap
1099 * @bits: number of bits in the bitmap
1100 * @order: region size (log base 2 of number of bits) to find
1102 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1103 * allocate them (set them to one). Only consider regions of length
1104 * a power (@order) of two, aligned to that power of two, which
1105 * makes the search algorithm much faster.
1107 * Return the bit offset in bitmap of the allocated region,
1108 * or -errno on failure.
1110 int bitmap_find_free_region(unsigned long *bitmap
, unsigned int bits
, int order
)
1112 unsigned int pos
, end
; /* scans bitmap by regions of size order */
1114 for (pos
= 0 ; (end
= pos
+ (1U << order
)) <= bits
; pos
= end
) {
1115 if (!__reg_op(bitmap
, pos
, order
, REG_OP_ISFREE
))
1117 __reg_op(bitmap
, pos
, order
, REG_OP_ALLOC
);
1122 EXPORT_SYMBOL(bitmap_find_free_region
);
1125 * bitmap_release_region - release allocated bitmap region
1126 * @bitmap: array of unsigned longs corresponding to the bitmap
1127 * @pos: beginning of bit region to release
1128 * @order: region size (log base 2 of number of bits) to release
1130 * This is the complement to __bitmap_find_free_region() and releases
1131 * the found region (by clearing it in the bitmap).
1135 void bitmap_release_region(unsigned long *bitmap
, unsigned int pos
, int order
)
1137 __reg_op(bitmap
, pos
, order
, REG_OP_RELEASE
);
1139 EXPORT_SYMBOL(bitmap_release_region
);
1142 * bitmap_allocate_region - allocate bitmap region
1143 * @bitmap: array of unsigned longs corresponding to the bitmap
1144 * @pos: beginning of bit region to allocate
1145 * @order: region size (log base 2 of number of bits) to allocate
1147 * Allocate (set bits in) a specified region of a bitmap.
1149 * Return 0 on success, or %-EBUSY if specified region wasn't
1150 * free (not all bits were zero).
1152 int bitmap_allocate_region(unsigned long *bitmap
, unsigned int pos
, int order
)
1154 if (!__reg_op(bitmap
, pos
, order
, REG_OP_ISFREE
))
1156 return __reg_op(bitmap
, pos
, order
, REG_OP_ALLOC
);
1158 EXPORT_SYMBOL(bitmap_allocate_region
);
1161 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1162 * @dst: destination buffer
1163 * @src: bitmap to copy
1164 * @nbits: number of bits in the bitmap
1166 * Require nbits % BITS_PER_LONG == 0.
1169 void bitmap_copy_le(unsigned long *dst
, const unsigned long *src
, unsigned int nbits
)
1173 for (i
= 0; i
< nbits
/BITS_PER_LONG
; i
++) {
1174 if (BITS_PER_LONG
== 64)
1175 dst
[i
] = cpu_to_le64(src
[i
]);
1177 dst
[i
] = cpu_to_le32(src
[i
]);
1180 EXPORT_SYMBOL(bitmap_copy_le
);
1183 unsigned long *bitmap_alloc(unsigned int nbits
, gfp_t flags
)
1185 return kmalloc_array(BITS_TO_LONGS(nbits
), sizeof(unsigned long),
1188 EXPORT_SYMBOL(bitmap_alloc
);
1190 unsigned long *bitmap_zalloc(unsigned int nbits
, gfp_t flags
)
1192 return bitmap_alloc(nbits
, flags
| __GFP_ZERO
);
1194 EXPORT_SYMBOL(bitmap_zalloc
);
1196 void bitmap_free(const unsigned long *bitmap
)
1200 EXPORT_SYMBOL(bitmap_free
);
1202 #if BITS_PER_LONG == 64
1204 * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
1205 * @bitmap: array of unsigned longs, the destination bitmap
1206 * @buf: array of u32 (in host byte order), the source bitmap
1207 * @nbits: number of bits in @bitmap
1209 void bitmap_from_arr32(unsigned long *bitmap
, const u32
*buf
, unsigned int nbits
)
1211 unsigned int i
, halfwords
;
1213 halfwords
= DIV_ROUND_UP(nbits
, 32);
1214 for (i
= 0; i
< halfwords
; i
++) {
1215 bitmap
[i
/2] = (unsigned long) buf
[i
];
1216 if (++i
< halfwords
)
1217 bitmap
[i
/2] |= ((unsigned long) buf
[i
]) << 32;
1220 /* Clear tail bits in last word beyond nbits. */
1221 if (nbits
% BITS_PER_LONG
)
1222 bitmap
[(halfwords
- 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits
);
1224 EXPORT_SYMBOL(bitmap_from_arr32
);
1227 * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
1228 * @buf: array of u32 (in host byte order), the dest bitmap
1229 * @bitmap: array of unsigned longs, the source bitmap
1230 * @nbits: number of bits in @bitmap
1232 void bitmap_to_arr32(u32
*buf
, const unsigned long *bitmap
, unsigned int nbits
)
1234 unsigned int i
, halfwords
;
1236 halfwords
= DIV_ROUND_UP(nbits
, 32);
1237 for (i
= 0; i
< halfwords
; i
++) {
1238 buf
[i
] = (u32
) (bitmap
[i
/2] & UINT_MAX
);
1239 if (++i
< halfwords
)
1240 buf
[i
] = (u32
) (bitmap
[i
/2] >> 32);
1243 /* Clear tail bits in last element of array beyond nbits. */
1244 if (nbits
% BITS_PER_LONG
)
1245 buf
[halfwords
- 1] &= (u32
) (UINT_MAX
>> ((-nbits
) & 31));
1247 EXPORT_SYMBOL(bitmap_to_arr32
);