X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fbitmap.c;h=2c9242e3fed01ca348b4171db2c0d89333fa357e;hb=2e6c4e5101633a54aeee1f2e83020ee77fcb70d2;hp=fb9371fdd44a43c4e8e4fc9304f0ee00d3b4df8c;hpb=31151ba2cef171344beac254e65bd7e00138bb0d;p=linux-2.6 diff --git a/lib/bitmap.c b/lib/bitmap.c index fb9371fdd4..2c9242e3fe 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -95,12 +95,12 @@ void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits) } EXPORT_SYMBOL(__bitmap_complement); -/* +/** * __bitmap_shift_right - logical right shift of the bits in a bitmap - * @dst - destination bitmap - * @src - source bitmap - * @nbits - shift by this many bits - * @bits - bitmap size, in bits + * @dst : destination bitmap + * @src : source bitmap + * @shift : shift by this many bits + * @bits : bitmap size, in bits * * Shifting right (dividing) means moving bits in the MS -> LS bit * direction. Zeros are fed into the vacated MS positions and the @@ -139,12 +139,12 @@ void __bitmap_shift_right(unsigned long *dst, EXPORT_SYMBOL(__bitmap_shift_right); -/* +/** * __bitmap_shift_left - logical left shift of the bits in a bitmap - * @dst - destination bitmap - * @src - source bitmap - * @nbits - shift by this many bits - * @bits - bitmap size, in bits + * @dst : destination bitmap + * @src : source bitmap + * @shift : shift by this many bits + * @bits : bitmap size, in bits * * Shifting left (multiplying) means moving bits in the LS -> MS * direction. Zeros are fed into the vacated LS bit positions @@ -253,33 +253,18 @@ int __bitmap_subset(const unsigned long *bitmap1, } EXPORT_SYMBOL(__bitmap_subset); -#if BITS_PER_LONG == 32 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 += hweight32(bitmap[k]); + w += hweight_long(bitmap[k]); if (bits % BITS_PER_LONG) - w += hweight32(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); + w += hweight_long(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); return w; } -#else -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]); - - if (bits % BITS_PER_LONG) - w += hweight64(bitmap[k] & BITMAP_LAST_WORD_MASK(bits)); - - return w; -} -#endif EXPORT_SYMBOL(__bitmap_weight); /* @@ -331,25 +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); @@ -358,11 +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; @@ -403,11 +395,36 @@ int bitmap_parse(const char __user *ubuf, unsigned int ubuflen, 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); +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) @@ -452,6 +469,10 @@ int bitmap_scnlistprintf(char *buf, unsigned int buflen, /* current bit is 'cur', most recently seen range is [rbot, rtop] */ int cur, rbot, rtop; + if (buflen == 0) + return 0; + buf[0] = 0; + rbot = cur = find_first_bit(maskp, nmaskbits); while (cur < nmaskbits) { rtop = cur; @@ -467,8 +488,8 @@ EXPORT_SYMBOL(bitmap_scnlistprintf); /** * bitmap_parselist - convert list format ASCII string to bitmap - * @buf: read nul-terminated user string from this buffer - * @mask: write resulting mask here + * @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 @@ -476,10 +497,11 @@ EXPORT_SYMBOL(bitmap_scnlistprintf); * decimal numbers, the smallest and largest bit numbers set in * the range. * - * Returns 0 on success, -errno on invalid input strings: - * -EINVAL: second number in range smaller than first - * -EINVAL: invalid character in string - * -ERANGE: bit number specified too large for mask + * 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) { @@ -512,83 +534,307 @@ int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) EXPORT_SYMBOL(bitmap_parselist); /** - * bitmap_find_free_region - find a contiguous aligned mem region - * @bitmap: an array of unsigned longs corresponding to the bitmap - * @bits: number of bits in the bitmap - * @order: region size to find (size is actually 1<= 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) { - unsigned long mask; - int pages = 1 << order; - int i; + 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); - if(pages > BITS_PER_LONG) - return -EINVAL; +/** + * 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); - /* make a mask of the order */ - mask = (1ul << (pages - 1)); +/* + * 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; - /* run up the bitmap pages bits at a time */ - for (i = 0; i < bits; i += pages) { - int index = i/BITS_PER_LONG; - int offset = i - (index * BITS_PER_LONG); - if((bitmap[index] & (mask << offset)) == 0) { - /* set region in bimap */ - bitmap[index] |= (mask << offset); - return i; + 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; } - return -ENOMEM; +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: a pointer to the bitmap - * @pos: the beginning of the region - * @order: the order of the bits to release (number is 1< BITS_PER_LONG. The - * algorithm would be a simple look for multiple zeros in the - * array, but there's no driver today that needs this. If you - * trip this BUG(), you get to code it... */ - BUG_ON(pages > BITS_PER_LONG); - mask += mask - 1; - if (bitmap[index] & (mask << offset)) + if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) return -EBUSY; - bitmap[index] |= (mask << offset); + __reg_op(bitmap, pos, order, REG_OP_ALLOC); return 0; } EXPORT_SYMBOL(bitmap_allocate_region);