X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fbitmap.c;h=037fa9aa2ed77f554296c7f1f4b64f769fdd2a73;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=779d30365e46171451759fb65a294415490d82d0;hpb=5273a3df6485dc2ad6aa7ddd441b9a21970f003b;p=linux-2.6.git diff --git a/lib/bitmap.c b/lib/bitmap.c index 779d30365..037fa9aa2 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -9,10 +9,36 @@ #include #include #include -#include +#include #include -int bitmap_empty(const unsigned long *bitmap, int bits) +/* + * bitmaps provide an array of bits, implemented using an an + * array of unsigned longs. The number of valid bits in a + * given bitmap does _not_ need to be an exact multiple of + * BITS_PER_LONG. + * + * The possible unused bits in the last, partially used word + * of a bitmap are 'don't care'. The implementation makes + * no particular effort to keep them zero. It ensures that + * their value will not affect the results of any operation. + * The bitmap operations that return Boolean (bitmap_empty, + * for example) or scalar (bitmap_weight, for example) results + * carefully filter out these unused bits from impacting their + * results. + * + * These operations actually hold to a slightly stronger rule: + * if you don't input any bitmaps to these ops that have some + * unused bits set, then they won't output any set unused bits + * in output bitmaps. + * + * The byte ordering of bitmaps is more natural on little + * endian architectures. See the big-endian headers + * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h + * for the best explanations of this ordering. + */ + +int __bitmap_empty(const unsigned long *bitmap, int bits) { int k, lim = bits/BITS_PER_LONG; for (k = 0; k < lim; ++k) @@ -20,14 +46,14 @@ int bitmap_empty(const unsigned long *bitmap, int bits) return 0; if (bits % BITS_PER_LONG) - if (bitmap[k] & ((1UL << (bits % BITS_PER_LONG)) - 1)) + if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) return 0; return 1; } -EXPORT_SYMBOL(bitmap_empty); +EXPORT_SYMBOL(__bitmap_empty); -int bitmap_full(const unsigned long *bitmap, int bits) +int __bitmap_full(const unsigned long *bitmap, int bits) { int k, lim = bits/BITS_PER_LONG; for (k = 0; k < lim; ++k) @@ -35,15 +61,15 @@ int bitmap_full(const unsigned long *bitmap, int bits) return 0; if (bits % BITS_PER_LONG) - if (~bitmap[k] & ((1UL << (bits % BITS_PER_LONG)) - 1)) + if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits)) return 0; return 1; } -EXPORT_SYMBOL(bitmap_full); +EXPORT_SYMBOL(__bitmap_full); -int bitmap_equal(const unsigned long *bitmap1, - unsigned long *bitmap2, int bits) +int __bitmap_equal(const unsigned long *bitmap1, + const unsigned long *bitmap2, int bits) { int k, lim = bits/BITS_PER_LONG; for (k = 0; k < lim; ++k) @@ -51,26 +77,26 @@ int bitmap_equal(const unsigned long *bitmap1, return 0; if (bits % BITS_PER_LONG) - if ((bitmap1[k] ^ bitmap2[k]) & - ((1UL << (bits % BITS_PER_LONG)) - 1)) + if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) return 0; return 1; } -EXPORT_SYMBOL(bitmap_equal); +EXPORT_SYMBOL(__bitmap_equal); -void bitmap_complement(unsigned long *bitmap, int bits) +void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits) { - int k; - int nr = BITS_TO_LONGS(bits); + int k, lim = bits/BITS_PER_LONG; + for (k = 0; k < lim; ++k) + dst[k] = ~src[k]; - for (k = 0; k < nr; ++k) - bitmap[k] = ~bitmap[k]; + if (bits % BITS_PER_LONG) + dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits); } -EXPORT_SYMBOL(bitmap_complement); +EXPORT_SYMBOL(__bitmap_complement); /* - * bitmap_shift_right - logical right shift of the bits in a bitmap + * __bitmap_shift_right - logical right shift of the bits in a bitmap * @dst - destination bitmap * @src - source bitmap * @nbits - shift by this many bits @@ -80,7 +106,7 @@ EXPORT_SYMBOL(bitmap_complement); * direction. Zeros are fed into the vacated MS positions and the * LS bits shifted off the bottom are lost. */ -void bitmap_shift_right(unsigned long *dst, +void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, int shift, int bits) { int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG; @@ -110,10 +136,11 @@ void bitmap_shift_right(unsigned long *dst, if (off) memset(&dst[lim - off], 0, off*sizeof(unsigned long)); } -EXPORT_SYMBOL(bitmap_shift_right); +EXPORT_SYMBOL(__bitmap_shift_right); + /* - * bitmap_shift_left - logical left shift of the bits in a bitmap + * __bitmap_shift_left - logical left shift of the bits in a bitmap * @dst - destination bitmap * @src - source bitmap * @nbits - shift by this many bits @@ -123,7 +150,8 @@ EXPORT_SYMBOL(bitmap_shift_right); * direction. Zeros are fed into the vacated LS bit positions * and those MS bits shifted off the top are lost. */ -void bitmap_shift_left(unsigned long *dst, + +void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, int shift, int bits) { int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG; @@ -149,9 +177,9 @@ void bitmap_shift_left(unsigned long *dst, if (off) memset(dst, 0, off*sizeof(unsigned long)); } -EXPORT_SYMBOL(bitmap_shift_left); +EXPORT_SYMBOL(__bitmap_shift_left); -void bitmap_and(unsigned long *dst, const unsigned long *bitmap1, +void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, int bits) { int k; @@ -160,9 +188,9 @@ void bitmap_and(unsigned long *dst, const unsigned long *bitmap1, for (k = 0; k < nr; k++) dst[k] = bitmap1[k] & bitmap2[k]; } -EXPORT_SYMBOL(bitmap_and); +EXPORT_SYMBOL(__bitmap_and); -void bitmap_or(unsigned long *dst, const unsigned long *bitmap1, +void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, int bits) { int k; @@ -171,38 +199,73 @@ void bitmap_or(unsigned long *dst, const unsigned long *bitmap1, for (k = 0; k < nr; k++) dst[k] = bitmap1[k] | bitmap2[k]; } -EXPORT_SYMBOL(bitmap_or); +EXPORT_SYMBOL(__bitmap_or); -#if BITS_PER_LONG == 32 -int bitmap_weight(const unsigned long *bitmap, int bits) +void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, + const unsigned long *bitmap2, int bits) { - int k, w = 0, lim = bits/BITS_PER_LONG; + int k; + int nr = BITS_TO_LONGS(bits); - for (k = 0; k < lim; k++) - w += hweight32(bitmap[k]); + for (k = 0; k < nr; k++) + dst[k] = bitmap1[k] ^ bitmap2[k]; +} +EXPORT_SYMBOL(__bitmap_xor); + +void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, + const unsigned long *bitmap2, int bits) +{ + int k; + int nr = BITS_TO_LONGS(bits); + + for (k = 0; k < nr; k++) + dst[k] = bitmap1[k] & ~bitmap2[k]; +} +EXPORT_SYMBOL(__bitmap_andnot); + +int __bitmap_intersects(const unsigned long *bitmap1, + const unsigned long *bitmap2, int bits) +{ + int k, lim = bits/BITS_PER_LONG; + for (k = 0; k < lim; ++k) + if (bitmap1[k] & bitmap2[k]) + return 1; if (bits % BITS_PER_LONG) - w += hweight32(bitmap[k] & - ((1UL << (bits % BITS_PER_LONG)) - 1)); + if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) + return 1; + return 0; +} +EXPORT_SYMBOL(__bitmap_intersects); - return w; +int __bitmap_subset(const unsigned long *bitmap1, + const unsigned long *bitmap2, int bits) +{ + int k, lim = bits/BITS_PER_LONG; + for (k = 0; k < lim; ++k) + if (bitmap1[k] & ~bitmap2[k]) + return 0; + + if (bits % BITS_PER_LONG) + if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) + return 0; + return 1; } -#else -int bitmap_weight(const unsigned long *bitmap, int bits) +EXPORT_SYMBOL(__bitmap_subset); + +int __bitmap_weight(const unsigned long *bitmap, int bits) { int k, w = 0, lim = bits/BITS_PER_LONG; for (k = 0; k < lim; k++) - w += hweight64(bitmap[k]); + w += hweight_long(bitmap[k]); if (bits % BITS_PER_LONG) - w += hweight64(bitmap[k] & - ((1UL << (bits % BITS_PER_LONG)) - 1)); + w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); return w; } -#endif -EXPORT_SYMBOL(bitmap_weight); +EXPORT_SYMBOL(__bitmap_weight); /* * Bitmap printing & parsing functions: first version by Bill Irwin, @@ -211,8 +274,8 @@ EXPORT_SYMBOL(bitmap_weight); #define CHUNKSZ 32 #define nbits_to_hold_value(val) fls(val) -#define roundup_power2(val,modulus) (((val) + (modulus) - 1) & ~((modulus) - 1)) #define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10)) +#define BASEDEC 10 /* fancier cpuset lists input in decimal */ /** * bitmap_scnprintf - convert bitmap to an ASCII hex string. @@ -237,7 +300,7 @@ int bitmap_scnprintf(char *buf, unsigned int buflen, if (chunksz == 0) chunksz = CHUNKSZ; - i = roundup_power2(nmaskbits, CHUNKSZ) - CHUNKSZ; + i = ALIGN(nmaskbits, CHUNKSZ) - CHUNKSZ; for (; i >= 0; i -= CHUNKSZ) { chunkmask = ((1ULL << chunksz) - 1); word = i / BITS_PER_LONG; @@ -253,25 +316,28 @@ int bitmap_scnprintf(char *buf, unsigned int buflen, EXPORT_SYMBOL(bitmap_scnprintf); /** - * bitmap_parse - convert an ASCII hex string into a bitmap. - * @buf: pointer to buffer in user space containing string. + * __bitmap_parse - convert an ASCII hex string into a bitmap. + * @buf: pointer to buffer containing string. * @buflen: buffer size in bytes. If string is smaller than this * then it must be terminated with a \0. + * @is_user: location of buffer, 0 indicates kernel space * @maskp: pointer to bitmap array that will contain result. * @nmaskbits: size of bitmap, in bits. * * Commas group hex digits into chunks. Each chunk defines exactly 32 * bits of the resultant bitmask. No chunk may specify a value larger - * than 32 bits (-EOVERFLOW), and if a chunk specifies a smaller value - * then leading 0-bits are prepended. -EINVAL is returned for illegal + * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value + * then leading 0-bits are prepended. %-EINVAL is returned for illegal * characters and for grouping errors such as "1,,5", ",44", "," and "". * Leading and trailing whitespace accepted, but not embedded whitespace. */ -int bitmap_parse(const char __user *ubuf, unsigned int ubuflen, - unsigned long *maskp, int nmaskbits) +int __bitmap_parse(const char *buf, unsigned int buflen, + int is_user, unsigned long *maskp, + int nmaskbits) { int c, old_c, totaldigits, ndigits, nchunks, nbits; u32 chunk; + const char __user *ubuf = buf; bitmap_zero(maskp, nmaskbits); @@ -280,11 +346,15 @@ int bitmap_parse(const char __user *ubuf, unsigned int ubuflen, chunk = ndigits = 0; /* Get the next chunk of the bitmap */ - while (ubuflen) { + while (buflen) { old_c = c; - if (get_user(c, ubuf++)) - return -EFAULT; - ubuflen--; + if (is_user) { + if (__get_user(c, ubuf++)) + return -EFAULT; + } + else + c = *buf++; + buflen--; if (isspace(c)) continue; @@ -319,14 +389,448 @@ int bitmap_parse(const char __user *ubuf, unsigned int ubuflen, if (nchunks == 0 && chunk == 0) continue; - bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); + __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits); *maskp |= chunk; nchunks++; nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ; if (nbits > nmaskbits) return -EOVERFLOW; - } while (ubuflen && c == ','); + } while (buflen && c == ','); + + return 0; +} +EXPORT_SYMBOL(__bitmap_parse); + +/** + * bitmap_parse_user() + * + * @ubuf: pointer to user buffer containing string. + * @ulen: buffer size in bytes. If string is smaller than this + * then it must be terminated with a \0. + * @maskp: pointer to bitmap array that will contain result. + * @nmaskbits: size of bitmap, in bits. + * + * Wrapper for __bitmap_parse(), providing it with user buffer. + * + * We cannot have this as an inline function in bitmap.h because it needs + * linux/uaccess.h to get the access_ok() declaration and this causes + * cyclic dependencies. + */ +int bitmap_parse_user(const char __user *ubuf, + unsigned int ulen, unsigned long *maskp, + int nmaskbits) +{ + if (!access_ok(VERIFY_READ, ubuf, ulen)) + return -EFAULT; + return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits); +} +EXPORT_SYMBOL(bitmap_parse_user); + +/* + * bscnl_emit(buf, buflen, rbot, rtop, bp) + * + * Helper routine for bitmap_scnlistprintf(). Write decimal number + * or range to buf, suppressing output past buf+buflen, with optional + * comma-prefix. Return len of what would be written to buf, if it + * all fit. + */ +static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len) +{ + if (len > 0) + len += scnprintf(buf + len, buflen - len, ","); + if (rbot == rtop) + len += scnprintf(buf + len, buflen - len, "%d", rbot); + else + len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop); + return len; +} + +/** + * bitmap_scnlistprintf - convert bitmap to list format ASCII string + * @buf: byte buffer into which string is placed + * @buflen: reserved size of @buf, in bytes + * @maskp: pointer to bitmap to convert + * @nmaskbits: size of bitmap, in bits + * + * Output format is a comma-separated list of decimal numbers and + * ranges. Consecutively set bits are shown as two hyphen-separated + * decimal numbers, the smallest and largest bit numbers set in + * the range. Output format is compatible with the format + * accepted as input by bitmap_parselist(). + * + * The return value is the number of characters which would be + * generated for the given input, excluding the trailing '\0', as + * per ISO C99. + */ +int bitmap_scnlistprintf(char *buf, unsigned int buflen, + const unsigned long *maskp, int nmaskbits) +{ + int len = 0; + /* current bit is 'cur', most recently seen range is [rbot, rtop] */ + int cur, rbot, rtop; + + rbot = cur = find_first_bit(maskp, nmaskbits); + while (cur < nmaskbits) { + rtop = cur; + cur = find_next_bit(maskp, nmaskbits, cur+1); + if (cur >= nmaskbits || cur > rtop + 1) { + len = bscnl_emit(buf, buflen, rbot, rtop, len); + rbot = cur; + } + } + return len; +} +EXPORT_SYMBOL(bitmap_scnlistprintf); + +/** + * bitmap_parselist - convert list format ASCII string to bitmap + * @bp: read nul-terminated user string from this buffer + * @maskp: write resulting mask here + * @nmaskbits: number of bits in mask to be written + * + * Input format is a comma-separated list of decimal numbers and + * ranges. Consecutively set bits are shown as two hyphen-separated + * decimal numbers, the smallest and largest bit numbers set in + * the range. + * + * Returns 0 on success, -errno on invalid input strings. + * Error values: + * %-EINVAL: second number in range smaller than first + * %-EINVAL: invalid character in string + * %-ERANGE: bit number specified too large for mask + */ +int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) +{ + unsigned a, b; + + bitmap_zero(maskp, nmaskbits); + do { + if (!isdigit(*bp)) + return -EINVAL; + b = a = simple_strtoul(bp, (char **)&bp, BASEDEC); + if (*bp == '-') { + bp++; + if (!isdigit(*bp)) + return -EINVAL; + b = simple_strtoul(bp, (char **)&bp, BASEDEC); + } + if (!(a <= b)) + return -EINVAL; + if (b >= nmaskbits) + return -ERANGE; + while (a <= b) { + set_bit(a, maskp); + a++; + } + if (*bp == ',') + bp++; + } while (*bp != '\0' && *bp != '\n'); + return 0; +} +EXPORT_SYMBOL(bitmap_parselist); + +/* + * bitmap_pos_to_ord(buf, pos, bits) + * @buf: pointer to a bitmap + * @pos: a bit position in @buf (0 <= @pos < @bits) + * @bits: number of valid bit positions in @buf + * + * Map the bit at position @pos in @buf (of length @bits) to the + * ordinal of which set bit it is. If it is not set or if @pos + * is not a valid bit position, map to -1. + * + * If for example, just bits 4 through 7 are set in @buf, then @pos + * values 4 through 7 will get mapped to 0 through 3, respectively, + * and other @pos values will get mapped to 0. When @pos value 7 + * gets mapped to (returns) @ord value 3 in this example, that means + * that bit 7 is the 3rd (starting with 0th) set bit in @buf. + * + * The bit positions 0 through @bits are valid positions in @buf. + */ +static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits) +{ + int i, ord; + + if (pos < 0 || pos >= bits || !test_bit(pos, buf)) + return -1; + + i = find_first_bit(buf, bits); + ord = 0; + while (i < pos) { + i = find_next_bit(buf, bits, i + 1); + ord++; + } + BUG_ON(i != pos); + + return ord; +} + +/** + * bitmap_ord_to_pos(buf, ord, bits) + * @buf: pointer to bitmap + * @ord: ordinal bit position (n-th set bit, n >= 0) + * @bits: number of valid bit positions in @buf + * + * Map the ordinal offset of bit @ord in @buf to its position in @buf. + * Value of @ord should be in range 0 <= @ord < weight(buf), else + * results are undefined. + * + * If for example, just bits 4 through 7 are set in @buf, then @ord + * values 0 through 3 will get mapped to 4 through 7, respectively, + * and all other @ord values return undefined values. When @ord value 3 + * gets mapped to (returns) @pos value 7 in this example, that means + * that the 3rd set bit (starting with 0th) is at position 7 in @buf. + * + * The bit positions 0 through @bits are valid positions in @buf. + */ +static int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) +{ + int pos = 0; + + if (ord >= 0 && ord < bits) { + int i; + + for (i = find_first_bit(buf, bits); + i < bits && ord > 0; + i = find_next_bit(buf, bits, i + 1)) + ord--; + if (i < bits && ord == 0) + pos = i; + } + return pos; +} + +/** + * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap + * @dst: remapped result + * @src: subset to be remapped + * @old: defines domain of map + * @new: defines range of map + * @bits: number of bits in each of these bitmaps + * + * Let @old and @new define a mapping of bit positions, such that + * whatever position is held by the n-th set bit in @old is mapped + * to the n-th set bit in @new. In the more general case, allowing + * for the possibility that the weight 'w' of @new is less than the + * weight of @old, map the position of the n-th set bit in @old to + * the position of the m-th set bit in @new, where m == n % w. + * + * If either of the @old and @new bitmaps are empty, or if @src and + * @dst point to the same location, then this routine copies @src + * to @dst. + * + * The positions of unset bits in @old are mapped to themselves + * (the identify map). + * + * Apply the above specified mapping to @src, placing the result in + * @dst, clearing any bits previously set in @dst. + * + * For example, lets say that @old has bits 4 through 7 set, and + * @new has bits 12 through 15 set. This defines the mapping of bit + * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other + * bit positions unchanged. So if say @src comes into this routine + * with bits 1, 5 and 7 set, then @dst should leave with bits 1, + * 13 and 15 set. + */ +void bitmap_remap(unsigned long *dst, const unsigned long *src, + const unsigned long *old, const unsigned long *new, + int bits) +{ + int oldbit, w; + + if (dst == src) /* following doesn't handle inplace remaps */ + return; + bitmap_zero(dst, bits); + + w = bitmap_weight(new, bits); + for (oldbit = find_first_bit(src, bits); + oldbit < bits; + oldbit = find_next_bit(src, bits, oldbit + 1)) { + int n = bitmap_pos_to_ord(old, oldbit, bits); + if (n < 0 || w == 0) + set_bit(oldbit, dst); /* identity map */ + else + set_bit(bitmap_ord_to_pos(new, n % w, bits), dst); + } +} +EXPORT_SYMBOL(bitmap_remap); + +/** + * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit + * @oldbit: bit position to be mapped + * @old: defines domain of map + * @new: defines range of map + * @bits: number of bits in each of these bitmaps + * + * Let @old and @new define a mapping of bit positions, such that + * whatever position is held by the n-th set bit in @old is mapped + * to the n-th set bit in @new. In the more general case, allowing + * for the possibility that the weight 'w' of @new is less than the + * weight of @old, map the position of the n-th set bit in @old to + * the position of the m-th set bit in @new, where m == n % w. + * + * The positions of unset bits in @old are mapped to themselves + * (the identify map). + * + * Apply the above specified mapping to bit position @oldbit, returning + * the new bit position. + * + * For example, lets say that @old has bits 4 through 7 set, and + * @new has bits 12 through 15 set. This defines the mapping of bit + * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other + * bit positions unchanged. So if say @oldbit is 5, then this routine + * returns 13. + */ +int bitmap_bitremap(int oldbit, const unsigned long *old, + const unsigned long *new, int bits) +{ + int w = bitmap_weight(new, bits); + int n = bitmap_pos_to_ord(old, oldbit, bits); + if (n < 0 || w == 0) + return oldbit; + else + return bitmap_ord_to_pos(new, n % w, bits); +} +EXPORT_SYMBOL(bitmap_bitremap); + +/* + * Common code for bitmap_*_region() routines. + * bitmap: array of unsigned longs corresponding to the bitmap + * pos: the beginning of the region + * order: region size (log base 2 of number of bits) + * reg_op: operation(s) to perform on that region of bitmap + * + * Can set, verify and/or release a region of bits in a bitmap, + * depending on which combination of REG_OP_* flag bits is set. + * + * A region of a bitmap is a sequence of bits in the bitmap, of + * some size '1 << order' (a power of two), aligned to that same + * '1 << order' power of two. + * + * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits). + * Returns 0 in all other cases and reg_ops. + */ + +enum { + REG_OP_ISFREE, /* true if region is all zero bits */ + REG_OP_ALLOC, /* set all bits in region */ + REG_OP_RELEASE, /* clear all bits in region */ +}; + +static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op) +{ + int nbits_reg; /* number of bits in region */ + int index; /* index first long of region in bitmap */ + int offset; /* bit offset region in bitmap[index] */ + int nlongs_reg; /* num longs spanned by region in bitmap */ + int nbitsinlong; /* num bits of region in each spanned long */ + unsigned long mask; /* bitmask for one long of region */ + int i; /* scans bitmap by longs */ + int ret = 0; /* return value */ + + /* + * Either nlongs_reg == 1 (for small orders that fit in one long) + * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) + */ + nbits_reg = 1 << order; + index = pos / BITS_PER_LONG; + offset = pos - (index * BITS_PER_LONG); + nlongs_reg = BITS_TO_LONGS(nbits_reg); + nbitsinlong = min(nbits_reg, BITS_PER_LONG); + + /* + * Can't do "mask = (1UL << nbitsinlong) - 1", as that + * overflows if nbitsinlong == BITS_PER_LONG. + */ + mask = (1UL << (nbitsinlong - 1)); + mask += mask - 1; + mask <<= offset; + + switch (reg_op) { + case REG_OP_ISFREE: + for (i = 0; i < nlongs_reg; i++) { + if (bitmap[index + i] & mask) + goto done; + } + ret = 1; /* all bits in region free (zero) */ + break; + + case REG_OP_ALLOC: + for (i = 0; i < nlongs_reg; i++) + bitmap[index + i] |= mask; + break; + + case REG_OP_RELEASE: + for (i = 0; i < nlongs_reg; i++) + bitmap[index + i] &= ~mask; + break; + } +done: + return ret; +} + +/** + * bitmap_find_free_region - find a contiguous aligned mem region + * @bitmap: array of unsigned longs corresponding to the bitmap + * @bits: number of bits in the bitmap + * @order: region size (log base 2 of number of bits) to find + * + * Find a region of free (zero) bits in a @bitmap of @bits bits and + * allocate them (set them to one). Only consider regions of length + * a power (@order) of two, aligned to that power of two, which + * makes the search algorithm much faster. + * + * Return the bit offset in bitmap of the allocated region, + * or -errno on failure. + */ +int bitmap_find_free_region(unsigned long *bitmap, int bits, int order) +{ + int pos; /* scans bitmap by regions of size order */ + + for (pos = 0; pos < bits; pos += (1 << order)) + if (__reg_op(bitmap, pos, order, REG_OP_ISFREE)) + break; + if (pos == bits) + return -ENOMEM; + __reg_op(bitmap, pos, order, REG_OP_ALLOC); + return pos; +} +EXPORT_SYMBOL(bitmap_find_free_region); + +/** + * bitmap_release_region - release allocated bitmap region + * @bitmap: array of unsigned longs corresponding to the bitmap + * @pos: beginning of bit region to release + * @order: region size (log base 2 of number of bits) to release + * + * This is the complement to __bitmap_find_free_region and releases + * the found region (by clearing it in the bitmap). + * + * No return value. + */ +void bitmap_release_region(unsigned long *bitmap, int pos, int order) +{ + __reg_op(bitmap, pos, order, REG_OP_RELEASE); +} +EXPORT_SYMBOL(bitmap_release_region); + +/** + * bitmap_allocate_region - allocate bitmap region + * @bitmap: array of unsigned longs corresponding to the bitmap + * @pos: beginning of bit region to allocate + * @order: region size (log base 2 of number of bits) to allocate + * + * Allocate (set bits in) a specified region of a bitmap. + * + * Return 0 on success, or %-EBUSY if specified region wasn't + * free (not all bits were zero). + */ +int bitmap_allocate_region(unsigned long *bitmap, int pos, int order) +{ + if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) + return -EBUSY; + __reg_op(bitmap, pos, order, REG_OP_ALLOC); return 0; } -EXPORT_SYMBOL(bitmap_parse); +EXPORT_SYMBOL(bitmap_allocate_region);