Root/lib/bitmap.c

Source at commit b386be689295730688885552666ea40b2e639b14 created 8 years 11 months ago.
By Maarten ter Huurne, Revert "MIPS: JZ4740: reset: Initialize hibernate wakeup counters."
1/*
2 * lib/bitmap.c
3 * Helper functions for bitmap.h.
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8#include <linux/module.h>
9#include <linux/ctype.h>
10#include <linux/errno.h>
11#include <linux/bitmap.h>
12#include <linux/bitops.h>
13#include <asm/uaccess.h>
14
15/*
16 * bitmaps provide an array of bits, implemented using an an
17 * array of unsigned longs. The number of valid bits in a
18 * given bitmap does _not_ need to be an exact multiple of
19 * BITS_PER_LONG.
20 *
21 * The possible unused bits in the last, partially used word
22 * of a bitmap are 'don't care'. The implementation makes
23 * no particular effort to keep them zero. It ensures that
24 * their value will not affect the results of any operation.
25 * The bitmap operations that return Boolean (bitmap_empty,
26 * for example) or scalar (bitmap_weight, for example) results
27 * carefully filter out these unused bits from impacting their
28 * results.
29 *
30 * These operations actually hold to a slightly stronger rule:
31 * if you don't input any bitmaps to these ops that have some
32 * unused bits set, then they won't output any set unused bits
33 * in output bitmaps.
34 *
35 * The byte ordering of bitmaps is more natural on little
36 * endian architectures. See the big-endian headers
37 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
38 * for the best explanations of this ordering.
39 */
40
41int __bitmap_empty(const unsigned long *bitmap, int bits)
42{
43    int k, lim = bits/BITS_PER_LONG;
44    for (k = 0; k < lim; ++k)
45        if (bitmap[k])
46            return 0;
47
48    if (bits % BITS_PER_LONG)
49        if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
50            return 0;
51
52    return 1;
53}
54EXPORT_SYMBOL(__bitmap_empty);
55
56int __bitmap_full(const unsigned long *bitmap, int bits)
57{
58    int k, lim = bits/BITS_PER_LONG;
59    for (k = 0; k < lim; ++k)
60        if (~bitmap[k])
61            return 0;
62
63    if (bits % BITS_PER_LONG)
64        if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
65            return 0;
66
67    return 1;
68}
69EXPORT_SYMBOL(__bitmap_full);
70
71int __bitmap_equal(const unsigned long *bitmap1,
72        const unsigned long *bitmap2, int bits)
73{
74    int k, lim = bits/BITS_PER_LONG;
75    for (k = 0; k < lim; ++k)
76        if (bitmap1[k] != bitmap2[k])
77            return 0;
78
79    if (bits % BITS_PER_LONG)
80        if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
81            return 0;
82
83    return 1;
84}
85EXPORT_SYMBOL(__bitmap_equal);
86
87void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
88{
89    int k, lim = bits/BITS_PER_LONG;
90    for (k = 0; k < lim; ++k)
91        dst[k] = ~src[k];
92
93    if (bits % BITS_PER_LONG)
94        dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
95}
96EXPORT_SYMBOL(__bitmap_complement);
97
98/**
99 * __bitmap_shift_right - logical right shift of the bits in a bitmap
100 * @dst : destination bitmap
101 * @src : source bitmap
102 * @shift : shift by this many bits
103 * @bits : bitmap size, in bits
104 *
105 * Shifting right (dividing) means moving bits in the MS -> LS bit
106 * direction. Zeros are fed into the vacated MS positions and the
107 * LS bits shifted off the bottom are lost.
108 */
109void __bitmap_shift_right(unsigned long *dst,
110            const unsigned long *src, int shift, int bits)
111{
112    int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
113    int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
114    unsigned long mask = (1UL << left) - 1;
115    for (k = 0; off + k < lim; ++k) {
116        unsigned long upper, lower;
117
118        /*
119         * If shift is not word aligned, take lower rem bits of
120         * word above and make them the top rem bits of result.
121         */
122        if (!rem || off + k + 1 >= lim)
123            upper = 0;
124        else {
125            upper = src[off + k + 1];
126            if (off + k + 1 == lim - 1 && left)
127                upper &= mask;
128        }
129        lower = src[off + k];
130        if (left && off + k == lim - 1)
131            lower &= mask;
132        dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
133        if (left && k == lim - 1)
134            dst[k] &= mask;
135    }
136    if (off)
137        memset(&dst[lim - off], 0, off*sizeof(unsigned long));
138}
139EXPORT_SYMBOL(__bitmap_shift_right);
140
141
142/**
143 * __bitmap_shift_left - logical left shift of the bits in a bitmap
144 * @dst : destination bitmap
145 * @src : source bitmap
146 * @shift : shift by this many bits
147 * @bits : bitmap size, in bits
148 *
149 * Shifting left (multiplying) means moving bits in the LS -> MS
150 * direction. Zeros are fed into the vacated LS bit positions
151 * and those MS bits shifted off the top are lost.
152 */
153
154void __bitmap_shift_left(unsigned long *dst,
155            const unsigned long *src, int shift, int bits)
156{
157    int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
158    int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
159    for (k = lim - off - 1; k >= 0; --k) {
160        unsigned long upper, lower;
161
162        /*
163         * If shift is not word aligned, take upper rem bits of
164         * word below and make them the bottom rem bits of result.
165         */
166        if (rem && k > 0)
167            lower = src[k - 1];
168        else
169            lower = 0;
170        upper = src[k];
171        if (left && k == lim - 1)
172            upper &= (1UL << left) - 1;
173        dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
174        if (left && k + off == lim - 1)
175            dst[k + off] &= (1UL << left) - 1;
176    }
177    if (off)
178        memset(dst, 0, off*sizeof(unsigned long));
179}
180EXPORT_SYMBOL(__bitmap_shift_left);
181
182int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
183                const unsigned long *bitmap2, int bits)
184{
185    int k;
186    int nr = BITS_TO_LONGS(bits);
187    unsigned long result = 0;
188
189    for (k = 0; k < nr; k++)
190        result |= (dst[k] = bitmap1[k] & bitmap2[k]);
191    return result != 0;
192}
193EXPORT_SYMBOL(__bitmap_and);
194
195void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
196                const unsigned long *bitmap2, int bits)
197{
198    int k;
199    int nr = BITS_TO_LONGS(bits);
200
201    for (k = 0; k < nr; k++)
202        dst[k] = bitmap1[k] | bitmap2[k];
203}
204EXPORT_SYMBOL(__bitmap_or);
205
206void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
207                const unsigned long *bitmap2, int bits)
208{
209    int k;
210    int nr = BITS_TO_LONGS(bits);
211
212    for (k = 0; k < nr; k++)
213        dst[k] = bitmap1[k] ^ bitmap2[k];
214}
215EXPORT_SYMBOL(__bitmap_xor);
216
217int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
218                const unsigned long *bitmap2, int bits)
219{
220    int k;
221    int nr = BITS_TO_LONGS(bits);
222    unsigned long result = 0;
223
224    for (k = 0; k < nr; k++)
225        result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
226    return result != 0;
227}
228EXPORT_SYMBOL(__bitmap_andnot);
229
230int __bitmap_intersects(const unsigned long *bitmap1,
231                const unsigned long *bitmap2, int bits)
232{
233    int k, lim = bits/BITS_PER_LONG;
234    for (k = 0; k < lim; ++k)
235        if (bitmap1[k] & bitmap2[k])
236            return 1;
237
238    if (bits % BITS_PER_LONG)
239        if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
240            return 1;
241    return 0;
242}
243EXPORT_SYMBOL(__bitmap_intersects);
244
245int __bitmap_subset(const unsigned long *bitmap1,
246                const unsigned long *bitmap2, int bits)
247{
248    int k, lim = bits/BITS_PER_LONG;
249    for (k = 0; k < lim; ++k)
250        if (bitmap1[k] & ~bitmap2[k])
251            return 0;
252
253    if (bits % BITS_PER_LONG)
254        if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
255            return 0;
256    return 1;
257}
258EXPORT_SYMBOL(__bitmap_subset);
259
260int __bitmap_weight(const unsigned long *bitmap, int bits)
261{
262    int k, w = 0, lim = bits/BITS_PER_LONG;
263
264    for (k = 0; k < lim; k++)
265        w += hweight_long(bitmap[k]);
266
267    if (bits % BITS_PER_LONG)
268        w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
269
270    return w;
271}
272EXPORT_SYMBOL(__bitmap_weight);
273
274void bitmap_set(unsigned long *map, int start, int nr)
275{
276    unsigned long *p = map + BIT_WORD(start);
277    const int size = start + nr;
278    int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
279    unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
280
281    while (nr - bits_to_set >= 0) {
282        *p |= mask_to_set;
283        nr -= bits_to_set;
284        bits_to_set = BITS_PER_LONG;
285        mask_to_set = ~0UL;
286        p++;
287    }
288    if (nr) {
289        mask_to_set &= BITMAP_LAST_WORD_MASK(size);
290        *p |= mask_to_set;
291    }
292}
293EXPORT_SYMBOL(bitmap_set);
294
295void bitmap_clear(unsigned long *map, int start, int nr)
296{
297    unsigned long *p = map + BIT_WORD(start);
298    const int size = start + nr;
299    int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
300    unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
301
302    while (nr - bits_to_clear >= 0) {
303        *p &= ~mask_to_clear;
304        nr -= bits_to_clear;
305        bits_to_clear = BITS_PER_LONG;
306        mask_to_clear = ~0UL;
307        p++;
308    }
309    if (nr) {
310        mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
311        *p &= ~mask_to_clear;
312    }
313}
314EXPORT_SYMBOL(bitmap_clear);
315
316/*
317 * bitmap_find_next_zero_area - find a contiguous aligned zero area
318 * @map: The address to base the search on
319 * @size: The bitmap size in bits
320 * @start: The bitnumber to start searching at
321 * @nr: The number of zeroed bits we're looking for
322 * @align_mask: Alignment mask for zero area
323 *
324 * The @align_mask should be one less than a power of 2; the effect is that
325 * the bit offset of all zero areas this function finds is multiples of that
326 * power of 2. A @align_mask of 0 means no alignment is required.
327 */
328unsigned long bitmap_find_next_zero_area(unsigned long *map,
329                     unsigned long size,
330                     unsigned long start,
331                     unsigned int nr,
332                     unsigned long align_mask)
333{
334    unsigned long index, end, i;
335again:
336    index = find_next_zero_bit(map, size, start);
337
338    /* Align allocation */
339    index = __ALIGN_MASK(index, align_mask);
340
341    end = index + nr;
342    if (end > size)
343        return end;
344    i = find_next_bit(map, end, index);
345    if (i < end) {
346        start = i + 1;
347        goto again;
348    }
349    return index;
350}
351EXPORT_SYMBOL(bitmap_find_next_zero_area);
352
353/*
354 * Bitmap printing & parsing functions: first version by Bill Irwin,
355 * second version by Paul Jackson, third by Joe Korty.
356 */
357
358#define CHUNKSZ 32
359#define nbits_to_hold_value(val) fls(val)
360#define BASEDEC 10 /* fancier cpuset lists input in decimal */
361
362/**
363 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
364 * @buf: byte buffer into which string is placed
365 * @buflen: reserved size of @buf, in bytes
366 * @maskp: pointer to bitmap to convert
367 * @nmaskbits: size of bitmap, in bits
368 *
369 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
370 * comma-separated sets of eight digits per set.
371 */
372int bitmap_scnprintf(char *buf, unsigned int buflen,
373    const unsigned long *maskp, int nmaskbits)
374{
375    int i, word, bit, len = 0;
376    unsigned long val;
377    const char *sep = "";
378    int chunksz;
379    u32 chunkmask;
380
381    chunksz = nmaskbits & (CHUNKSZ - 1);
382    if (chunksz == 0)
383        chunksz = CHUNKSZ;
384
385    i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ;
386    for (; i >= 0; i -= CHUNKSZ) {
387        chunkmask = ((1ULL << chunksz) - 1);
388        word = i / BITS_PER_LONG;
389        bit = i % BITS_PER_LONG;
390        val = (maskp[word] >> bit) & chunkmask;
391        len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
392            (chunksz+3)/4, val);
393        chunksz = CHUNKSZ;
394        sep = ",";
395    }
396    return len;
397}
398EXPORT_SYMBOL(bitmap_scnprintf);
399
400/**
401 * __bitmap_parse - convert an ASCII hex string into a bitmap.
402 * @buf: pointer to buffer containing string.
403 * @buflen: buffer size in bytes. If string is smaller than this
404 * then it must be terminated with a \0.
405 * @is_user: location of buffer, 0 indicates kernel space
406 * @maskp: pointer to bitmap array that will contain result.
407 * @nmaskbits: size of bitmap, in bits.
408 *
409 * Commas group hex digits into chunks. Each chunk defines exactly 32
410 * bits of the resultant bitmask. No chunk may specify a value larger
411 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
412 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
413 * characters and for grouping errors such as "1,,5", ",44", "," and "".
414 * Leading and trailing whitespace accepted, but not embedded whitespace.
415 */
416int __bitmap_parse(const char *buf, unsigned int buflen,
417        int is_user, unsigned long *maskp,
418        int nmaskbits)
419{
420    int c, old_c, totaldigits, ndigits, nchunks, nbits;
421    u32 chunk;
422    const char __user __force *ubuf = (const char __user __force *)buf;
423
424    bitmap_zero(maskp, nmaskbits);
425
426    nchunks = nbits = totaldigits = c = 0;
427    do {
428        chunk = ndigits = 0;
429
430        /* Get the next chunk of the bitmap */
431        while (buflen) {
432            old_c = c;
433            if (is_user) {
434                if (__get_user(c, ubuf++))
435                    return -EFAULT;
436            }
437            else
438                c = *buf++;
439            buflen--;
440            if (isspace(c))
441                continue;
442
443            /*
444             * If the last character was a space and the current
445             * character isn't '\0', we've got embedded whitespace.
446             * This is a no-no, so throw an error.
447             */
448            if (totaldigits && c && isspace(old_c))
449                return -EINVAL;
450
451            /* A '\0' or a ',' signal the end of the chunk */
452            if (c == '\0' || c == ',')
453                break;
454
455            if (!isxdigit(c))
456                return -EINVAL;
457
458            /*
459             * Make sure there are at least 4 free bits in 'chunk'.
460             * If not, this hexdigit will overflow 'chunk', so
461             * throw an error.
462             */
463            if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
464                return -EOVERFLOW;
465
466            chunk = (chunk << 4) | hex_to_bin(c);
467            ndigits++; totaldigits++;
468        }
469        if (ndigits == 0)
470            return -EINVAL;
471        if (nchunks == 0 && chunk == 0)
472            continue;
473
474        __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
475        *maskp |= chunk;
476        nchunks++;
477        nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
478        if (nbits > nmaskbits)
479            return -EOVERFLOW;
480    } while (buflen && c == ',');
481
482    return 0;
483}
484EXPORT_SYMBOL(__bitmap_parse);
485
486/**
487 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
488 *
489 * @ubuf: pointer to user buffer containing string.
490 * @ulen: buffer size in bytes. If string is smaller than this
491 * then it must be terminated with a \0.
492 * @maskp: pointer to bitmap array that will contain result.
493 * @nmaskbits: size of bitmap, in bits.
494 *
495 * Wrapper for __bitmap_parse(), providing it with user buffer.
496 *
497 * We cannot have this as an inline function in bitmap.h because it needs
498 * linux/uaccess.h to get the access_ok() declaration and this causes
499 * cyclic dependencies.
500 */
501int bitmap_parse_user(const char __user *ubuf,
502            unsigned int ulen, unsigned long *maskp,
503            int nmaskbits)
504{
505    if (!access_ok(VERIFY_READ, ubuf, ulen))
506        return -EFAULT;
507    return __bitmap_parse((const char __force *)ubuf,
508                ulen, 1, maskp, nmaskbits);
509
510}
511EXPORT_SYMBOL(bitmap_parse_user);
512
513/*
514 * bscnl_emit(buf, buflen, rbot, rtop, bp)
515 *
516 * Helper routine for bitmap_scnlistprintf(). Write decimal number
517 * or range to buf, suppressing output past buf+buflen, with optional
518 * comma-prefix. Return len of what would be written to buf, if it
519 * all fit.
520 */
521static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
522{
523    if (len > 0)
524        len += scnprintf(buf + len, buflen - len, ",");
525    if (rbot == rtop)
526        len += scnprintf(buf + len, buflen - len, "%d", rbot);
527    else
528        len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
529    return len;
530}
531
532/**
533 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
534 * @buf: byte buffer into which string is placed
535 * @buflen: reserved size of @buf, in bytes
536 * @maskp: pointer to bitmap to convert
537 * @nmaskbits: size of bitmap, in bits
538 *
539 * Output format is a comma-separated list of decimal numbers and
540 * ranges. Consecutively set bits are shown as two hyphen-separated
541 * decimal numbers, the smallest and largest bit numbers set in
542 * the range. Output format is compatible with the format
543 * accepted as input by bitmap_parselist().
544 *
545 * The return value is the number of characters which would be
546 * generated for the given input, excluding the trailing '\0', as
547 * per ISO C99.
548 */
549int bitmap_scnlistprintf(char *buf, unsigned int buflen,
550    const unsigned long *maskp, int nmaskbits)
551{
552    int len = 0;
553    /* current bit is 'cur', most recently seen range is [rbot, rtop] */
554    int cur, rbot, rtop;
555
556    if (buflen == 0)
557        return 0;
558    buf[0] = 0;
559
560    rbot = cur = find_first_bit(maskp, nmaskbits);
561    while (cur < nmaskbits) {
562        rtop = cur;
563        cur = find_next_bit(maskp, nmaskbits, cur+1);
564        if (cur >= nmaskbits || cur > rtop + 1) {
565            len = bscnl_emit(buf, buflen, rbot, rtop, len);
566            rbot = cur;
567        }
568    }
569    return len;
570}
571EXPORT_SYMBOL(bitmap_scnlistprintf);
572
573/**
574 * __bitmap_parselist - convert list format ASCII string to bitmap
575 * @buf: read nul-terminated user string from this buffer
576 * @buflen: buffer size in bytes. If string is smaller than this
577 * then it must be terminated with a \0.
578 * @is_user: location of buffer, 0 indicates kernel space
579 * @maskp: write resulting mask here
580 * @nmaskbits: number of bits in mask to be written
581 *
582 * Input format is a comma-separated list of decimal numbers and
583 * ranges. Consecutively set bits are shown as two hyphen-separated
584 * decimal numbers, the smallest and largest bit numbers set in
585 * the range.
586 *
587 * Returns 0 on success, -errno on invalid input strings.
588 * Error values:
589 * %-EINVAL: second number in range smaller than first
590 * %-EINVAL: invalid character in string
591 * %-ERANGE: bit number specified too large for mask
592 */
593static int __bitmap_parselist(const char *buf, unsigned int buflen,
594        int is_user, unsigned long *maskp,
595        int nmaskbits)
596{
597    unsigned a, b;
598    int c, old_c, totaldigits;
599    const char __user __force *ubuf = (const char __user __force *)buf;
600    int exp_digit, in_range;
601
602    totaldigits = c = 0;
603    bitmap_zero(maskp, nmaskbits);
604    do {
605        exp_digit = 1;
606        in_range = 0;
607        a = b = 0;
608
609        /* Get the next cpu# or a range of cpu#'s */
610        while (buflen) {
611            old_c = c;
612            if (is_user) {
613                if (__get_user(c, ubuf++))
614                    return -EFAULT;
615            } else
616                c = *buf++;
617            buflen--;
618            if (isspace(c))
619                continue;
620
621            /*
622             * If the last character was a space and the current
623             * character isn't '\0', we've got embedded whitespace.
624             * This is a no-no, so throw an error.
625             */
626            if (totaldigits && c && isspace(old_c))
627                return -EINVAL;
628
629            /* A '\0' or a ',' signal the end of a cpu# or range */
630            if (c == '\0' || c == ',')
631                break;
632
633            if (c == '-') {
634                if (exp_digit || in_range)
635                    return -EINVAL;
636                b = 0;
637                in_range = 1;
638                exp_digit = 1;
639                continue;
640            }
641
642            if (!isdigit(c))
643                return -EINVAL;
644
645            b = b * 10 + (c - '0');
646            if (!in_range)
647                a = b;
648            exp_digit = 0;
649            totaldigits++;
650        }
651        if (!(a <= b))
652            return -EINVAL;
653        if (b >= nmaskbits)
654            return -ERANGE;
655        while (a <= b) {
656            set_bit(a, maskp);
657            a++;
658        }
659    } while (buflen && c == ',');
660    return 0;
661}
662
663int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
664{
665    char *nl = strchr(bp, '\n');
666    int len;
667
668    if (nl)
669        len = nl - bp;
670    else
671        len = strlen(bp);
672
673    return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
674}
675EXPORT_SYMBOL(bitmap_parselist);
676
677
678/**
679 * bitmap_parselist_user()
680 *
681 * @ubuf: pointer to user buffer containing string.
682 * @ulen: buffer size in bytes. If string is smaller than this
683 * then it must be terminated with a \0.
684 * @maskp: pointer to bitmap array that will contain result.
685 * @nmaskbits: size of bitmap, in bits.
686 *
687 * Wrapper for bitmap_parselist(), providing it with user buffer.
688 *
689 * We cannot have this as an inline function in bitmap.h because it needs
690 * linux/uaccess.h to get the access_ok() declaration and this causes
691 * cyclic dependencies.
692 */
693int bitmap_parselist_user(const char __user *ubuf,
694            unsigned int ulen, unsigned long *maskp,
695            int nmaskbits)
696{
697    if (!access_ok(VERIFY_READ, ubuf, ulen))
698        return -EFAULT;
699    return __bitmap_parselist((const char __force *)ubuf,
700                    ulen, 1, maskp, nmaskbits);
701}
702EXPORT_SYMBOL(bitmap_parselist_user);
703
704
705/**
706 * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
707 * @buf: pointer to a bitmap
708 * @pos: a bit position in @buf (0 <= @pos < @bits)
709 * @bits: number of valid bit positions in @buf
710 *
711 * Map the bit at position @pos in @buf (of length @bits) to the
712 * ordinal of which set bit it is. If it is not set or if @pos
713 * is not a valid bit position, map to -1.
714 *
715 * If for example, just bits 4 through 7 are set in @buf, then @pos
716 * values 4 through 7 will get mapped to 0 through 3, respectively,
717 * and other @pos values will get mapped to 0. When @pos value 7
718 * gets mapped to (returns) @ord value 3 in this example, that means
719 * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
720 *
721 * The bit positions 0 through @bits are valid positions in @buf.
722 */
723static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
724{
725    int i, ord;
726
727    if (pos < 0 || pos >= bits || !test_bit(pos, buf))
728        return -1;
729
730    i = find_first_bit(buf, bits);
731    ord = 0;
732    while (i < pos) {
733        i = find_next_bit(buf, bits, i + 1);
734             ord++;
735    }
736    BUG_ON(i != pos);
737
738    return ord;
739}
740
741/**
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 * @bits: number of valid bit positions in @buf
746 *
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), else
749 * results are undefined.
750 *
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 return undefined values. 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.
756 *
757 * The bit positions 0 through @bits are valid positions in @buf.
758 */
759int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
760{
761    int pos = 0;
762
763    if (ord >= 0 && ord < bits) {
764        int i;
765
766        for (i = find_first_bit(buf, bits);
767             i < bits && ord > 0;
768             i = find_next_bit(buf, bits, i + 1))
769                 ord--;
770        if (i < bits && ord == 0)
771            pos = i;
772    }
773
774    return pos;
775}
776
777/**
778 * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
779 * @dst: remapped result
780 * @src: subset to be remapped
781 * @old: defines domain of map
782 * @new: defines range of map
783 * @bits: number of bits in each of these bitmaps
784 *
785 * Let @old and @new define a mapping of bit positions, such that
786 * whatever position is held by the n-th set bit in @old is mapped
787 * to the n-th set bit in @new. In the more general case, allowing
788 * for the possibility that the weight 'w' of @new is less than the
789 * weight of @old, map the position of the n-th set bit in @old to
790 * the position of the m-th set bit in @new, where m == n % w.
791 *
792 * If either of the @old and @new bitmaps are empty, or if @src and
793 * @dst point to the same location, then this routine copies @src
794 * to @dst.
795 *
796 * The positions of unset bits in @old are mapped to themselves
797 * (the identify map).
798 *
799 * Apply the above specified mapping to @src, placing the result in
800 * @dst, clearing any bits previously set in @dst.
801 *
802 * For example, lets say that @old has bits 4 through 7 set, and
803 * @new has bits 12 through 15 set. This defines the mapping of bit
804 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
805 * bit positions unchanged. So if say @src comes into this routine
806 * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
807 * 13 and 15 set.
808 */
809void bitmap_remap(unsigned long *dst, const unsigned long *src,
810        const unsigned long *old, const unsigned long *new,
811        int bits)
812{
813    int oldbit, w;
814
815    if (dst == src) /* following doesn't handle inplace remaps */
816        return;
817    bitmap_zero(dst, bits);
818
819    w = bitmap_weight(new, bits);
820    for_each_set_bit(oldbit, src, bits) {
821             int n = bitmap_pos_to_ord(old, oldbit, bits);
822
823        if (n < 0 || w == 0)
824            set_bit(oldbit, dst); /* identity map */
825        else
826            set_bit(bitmap_ord_to_pos(new, n % w, bits), dst);
827    }
828}
829EXPORT_SYMBOL(bitmap_remap);
830
831/**
832 * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
833 * @oldbit: bit position to be mapped
834 * @old: defines domain of map
835 * @new: defines range of map
836 * @bits: number of bits in each of these bitmaps
837 *
838 * Let @old and @new define a mapping of bit positions, such that
839 * whatever position is held by the n-th set bit in @old is mapped
840 * to the n-th set bit in @new. In the more general case, allowing
841 * for the possibility that the weight 'w' of @new is less than the
842 * weight of @old, map the position of the n-th set bit in @old to
843 * the position of the m-th set bit in @new, where m == n % w.
844 *
845 * The positions of unset bits in @old are mapped to themselves
846 * (the identify map).
847 *
848 * Apply the above specified mapping to bit position @oldbit, returning
849 * the new bit position.
850 *
851 * For example, lets say that @old has bits 4 through 7 set, and
852 * @new has bits 12 through 15 set. This defines the mapping of bit
853 * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
854 * bit positions unchanged. So if say @oldbit is 5, then this routine
855 * returns 13.
856 */
857int bitmap_bitremap(int oldbit, const unsigned long *old,
858                const unsigned long *new, int bits)
859{
860    int w = bitmap_weight(new, bits);
861    int n = bitmap_pos_to_ord(old, oldbit, bits);
862    if (n < 0 || w == 0)
863        return oldbit;
864    else
865        return bitmap_ord_to_pos(new, n % w, bits);
866}
867EXPORT_SYMBOL(bitmap_bitremap);
868
869/**
870 * bitmap_onto - translate one bitmap relative to another
871 * @dst: resulting translated bitmap
872 * @orig: original untranslated bitmap
873 * @relmap: bitmap relative to which translated
874 * @bits: number of bits in each of these bitmaps
875 *
876 * Set the n-th bit of @dst iff there exists some m such that the
877 * n-th bit of @relmap is set, the m-th bit of @orig is set, and
878 * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
879 * (If you understood the previous sentence the first time your
880 * read it, you're overqualified for your current job.)
881 *
882 * In other words, @orig is mapped onto (surjectively) @dst,
883 * using the the map { <n, m> | the n-th bit of @relmap is the
884 * m-th set bit of @relmap }.
885 *
886 * Any set bits in @orig above bit number W, where W is the
887 * weight of (number of set bits in) @relmap are mapped nowhere.
888 * In particular, if for all bits m set in @orig, m >= W, then
889 * @dst will end up empty. In situations where the possibility
890 * of such an empty result is not desired, one way to avoid it is
891 * to use the bitmap_fold() operator, below, to first fold the
892 * @orig bitmap over itself so that all its set bits x are in the
893 * range 0 <= x < W. The bitmap_fold() operator does this by
894 * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
895 *
896 * Example [1] for bitmap_onto():
897 * Let's say @relmap has bits 30-39 set, and @orig has bits
898 * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine,
899 * @dst will have bits 31, 33, 35, 37 and 39 set.
900 *
901 * When bit 0 is set in @orig, it means turn on the bit in
902 * @dst corresponding to whatever is the first bit (if any)
903 * that is turned on in @relmap. Since bit 0 was off in the
904 * above example, we leave off that bit (bit 30) in @dst.
905 *
906 * When bit 1 is set in @orig (as in the above example), it
907 * means turn on the bit in @dst corresponding to whatever
908 * is the second bit that is turned on in @relmap. The second
909 * bit in @relmap that was turned on in the above example was
910 * bit 31, so we turned on bit 31 in @dst.
911 *
912 * Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
913 * because they were the 4th, 6th, 8th and 10th set bits
914 * set in @relmap, and the 4th, 6th, 8th and 10th bits of
915 * @orig (i.e. bits 3, 5, 7 and 9) were also set.
916 *
917 * When bit 11 is set in @orig, it means turn on the bit in
918 * @dst corresponding to whatever is the twelfth bit that is
919 * turned on in @relmap. In the above example, there were
920 * only ten bits turned on in @relmap (30..39), so that bit
921 * 11 was set in @orig had no affect on @dst.
922 *
923 * Example [2] for bitmap_fold() + bitmap_onto():
924 * Let's say @relmap has these ten bits set:
925 * 40 41 42 43 45 48 53 61 74 95
926 * (for the curious, that's 40 plus the first ten terms of the
927 * Fibonacci sequence.)
928 *
929 * Further lets say we use the following code, invoking
930 * bitmap_fold() then bitmap_onto, as suggested above to
931 * avoid the possitility of an empty @dst result:
932 *
933 * unsigned long *tmp; // a temporary bitmap's bits
934 *
935 * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
936 * bitmap_onto(dst, tmp, relmap, bits);
937 *
938 * Then this table shows what various values of @dst would be, for
939 * various @orig's. I list the zero-based positions of each set bit.
940 * The tmp column shows the intermediate result, as computed by
941 * using bitmap_fold() to fold the @orig bitmap modulo ten
942 * (the weight of @relmap).
943 *
944 * @orig tmp @dst
945 * 0 0 40
946 * 1 1 41
947 * 9 9 95
948 * 10 0 40 (*)
949 * 1 3 5 7 1 3 5 7 41 43 48 61
950 * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45
951 * 0 9 18 27 0 9 8 7 40 61 74 95
952 * 0 10 20 30 0 40
953 * 0 11 22 33 0 1 2 3 40 41 42 43
954 * 0 12 24 36 0 2 4 6 40 42 45 53
955 * 78 102 211 1 2 8 41 42 74 (*)
956 *
957 * (*) For these marked lines, if we hadn't first done bitmap_fold()
958 * into tmp, then the @dst result would have been empty.
959 *
960 * If either of @orig or @relmap is empty (no set bits), then @dst
961 * will be returned empty.
962 *
963 * If (as explained above) the only set bits in @orig are in positions
964 * m where m >= W, (where W is the weight of @relmap) then @dst will
965 * once again be returned empty.
966 *
967 * All bits in @dst not set by the above rule are cleared.
968 */
969void bitmap_onto(unsigned long *dst, const unsigned long *orig,
970            const unsigned long *relmap, int bits)
971{
972    int n, m; /* same meaning as in above comment */
973
974    if (dst == orig) /* following doesn't handle inplace mappings */
975        return;
976    bitmap_zero(dst, bits);
977
978    /*
979     * The following code is a more efficient, but less
980     * obvious, equivalent to the loop:
981     * for (m = 0; m < bitmap_weight(relmap, bits); m++) {
982     * n = bitmap_ord_to_pos(orig, m, bits);
983     * if (test_bit(m, orig))
984     * set_bit(n, dst);
985     * }
986     */
987
988    m = 0;
989    for_each_set_bit(n, relmap, bits) {
990        /* m == bitmap_pos_to_ord(relmap, n, bits) */
991        if (test_bit(m, orig))
992            set_bit(n, dst);
993        m++;
994    }
995}
996EXPORT_SYMBOL(bitmap_onto);
997
998/**
999 * bitmap_fold - fold larger bitmap into smaller, modulo specified size
1000 * @dst: resulting smaller bitmap
1001 * @orig: original larger bitmap
1002 * @sz: specified size
1003 * @bits: number of bits in each of these bitmaps
1004 *
1005 * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
1006 * Clear all other bits in @dst. See further the comment and
1007 * Example [2] for bitmap_onto() for why and how to use this.
1008 */
1009void bitmap_fold(unsigned long *dst, const unsigned long *orig,
1010            int sz, int bits)
1011{
1012    int oldbit;
1013
1014    if (dst == orig) /* following doesn't handle inplace mappings */
1015        return;
1016    bitmap_zero(dst, bits);
1017
1018    for_each_set_bit(oldbit, orig, bits)
1019        set_bit(oldbit % sz, dst);
1020}
1021EXPORT_SYMBOL(bitmap_fold);
1022
1023/*
1024 * Common code for bitmap_*_region() routines.
1025 * bitmap: array of unsigned longs corresponding to the bitmap
1026 * pos: the beginning of the region
1027 * order: region size (log base 2 of number of bits)
1028 * reg_op: operation(s) to perform on that region of bitmap
1029 *
1030 * Can set, verify and/or release a region of bits in a bitmap,
1031 * depending on which combination of REG_OP_* flag bits is set.
1032 *
1033 * A region of a bitmap is a sequence of bits in the bitmap, of
1034 * some size '1 << order' (a power of two), aligned to that same
1035 * '1 << order' power of two.
1036 *
1037 * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
1038 * Returns 0 in all other cases and reg_ops.
1039 */
1040
1041enum {
1042    REG_OP_ISFREE, /* true if region is all zero bits */
1043    REG_OP_ALLOC, /* set all bits in region */
1044    REG_OP_RELEASE, /* clear all bits in region */
1045};
1046
1047static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op)
1048{
1049    int nbits_reg; /* number of bits in region */
1050    int index; /* index first long of region in bitmap */
1051    int offset; /* bit offset region in bitmap[index] */
1052    int nlongs_reg; /* num longs spanned by region in bitmap */
1053    int nbitsinlong; /* num bits of region in each spanned long */
1054    unsigned long mask; /* bitmask for one long of region */
1055    int i; /* scans bitmap by longs */
1056    int ret = 0; /* return value */
1057
1058    /*
1059     * Either nlongs_reg == 1 (for small orders that fit in one long)
1060     * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
1061     */
1062    nbits_reg = 1 << order;
1063    index = pos / BITS_PER_LONG;
1064    offset = pos - (index * BITS_PER_LONG);
1065    nlongs_reg = BITS_TO_LONGS(nbits_reg);
1066    nbitsinlong = min(nbits_reg, BITS_PER_LONG);
1067
1068    /*
1069     * Can't do "mask = (1UL << nbitsinlong) - 1", as that
1070     * overflows if nbitsinlong == BITS_PER_LONG.
1071     */
1072    mask = (1UL << (nbitsinlong - 1));
1073    mask += mask - 1;
1074    mask <<= offset;
1075
1076    switch (reg_op) {
1077    case REG_OP_ISFREE:
1078        for (i = 0; i < nlongs_reg; i++) {
1079            if (bitmap[index + i] & mask)
1080                goto done;
1081        }
1082        ret = 1; /* all bits in region free (zero) */
1083        break;
1084
1085    case REG_OP_ALLOC:
1086        for (i = 0; i < nlongs_reg; i++)
1087            bitmap[index + i] |= mask;
1088        break;
1089
1090    case REG_OP_RELEASE:
1091        for (i = 0; i < nlongs_reg; i++)
1092            bitmap[index + i] &= ~mask;
1093        break;
1094    }
1095done:
1096    return ret;
1097}
1098
1099/**
1100 * bitmap_find_free_region - find a contiguous aligned mem region
1101 * @bitmap: array of unsigned longs corresponding to the bitmap
1102 * @bits: number of bits in the bitmap
1103 * @order: region size (log base 2 of number of bits) to find
1104 *
1105 * Find a region of free (zero) bits in a @bitmap of @bits bits and
1106 * allocate them (set them to one). Only consider regions of length
1107 * a power (@order) of two, aligned to that power of two, which
1108 * makes the search algorithm much faster.
1109 *
1110 * Return the bit offset in bitmap of the allocated region,
1111 * or -errno on failure.
1112 */
1113int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
1114{
1115    int pos, end; /* scans bitmap by regions of size order */
1116
1117    for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) {
1118        if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1119            continue;
1120        __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1121        return pos;
1122    }
1123    return -ENOMEM;
1124}
1125EXPORT_SYMBOL(bitmap_find_free_region);
1126
1127/**
1128 * bitmap_release_region - release allocated bitmap region
1129 * @bitmap: array of unsigned longs corresponding to the bitmap
1130 * @pos: beginning of bit region to release
1131 * @order: region size (log base 2 of number of bits) to release
1132 *
1133 * This is the complement to __bitmap_find_free_region() and releases
1134 * the found region (by clearing it in the bitmap).
1135 *
1136 * No return value.
1137 */
1138void bitmap_release_region(unsigned long *bitmap, int pos, int order)
1139{
1140    __reg_op(bitmap, pos, order, REG_OP_RELEASE);
1141}
1142EXPORT_SYMBOL(bitmap_release_region);
1143
1144/**
1145 * bitmap_allocate_region - allocate bitmap region
1146 * @bitmap: array of unsigned longs corresponding to the bitmap
1147 * @pos: beginning of bit region to allocate
1148 * @order: region size (log base 2 of number of bits) to allocate
1149 *
1150 * Allocate (set bits in) a specified region of a bitmap.
1151 *
1152 * Return 0 on success, or %-EBUSY if specified region wasn't
1153 * free (not all bits were zero).
1154 */
1155int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
1156{
1157    if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
1158        return -EBUSY;
1159    __reg_op(bitmap, pos, order, REG_OP_ALLOC);
1160    return 0;
1161}
1162EXPORT_SYMBOL(bitmap_allocate_region);
1163
1164/**
1165 * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
1166 * @dst: destination buffer
1167 * @src: bitmap to copy
1168 * @nbits: number of bits in the bitmap
1169 *
1170 * Require nbits % BITS_PER_LONG == 0.
1171 */
1172void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
1173{
1174    unsigned long *d = dst;
1175    int i;
1176
1177    for (i = 0; i < nbits/BITS_PER_LONG; i++) {
1178        if (BITS_PER_LONG == 64)
1179            d[i] = cpu_to_le64(src[i]);
1180        else
1181            d[i] = cpu_to_le32(src[i]);
1182    }
1183}
1184EXPORT_SYMBOL(bitmap_copy_le);
1185

Archive Download this file



interactive