X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fbitmap.c;fp=lib%2Fbitmap.c;h=037fa9aa2ed77f554296c7f1f4b64f769fdd2a73;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=48e708381d44d0fb4ce1810aa24fc819ceaf7e2d;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/lib/bitmap.c b/lib/bitmap.c index 48e708381..037fa9aa2 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -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) @@ -467,8 +484,8 @@ 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 +493,11 @@ 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) { @@ -640,10 +658,10 @@ 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 + * @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 @@ -676,84 +694,143 @@ int bitmap_bitremap(int oldbit, const unsigned long *old, } EXPORT_SYMBOL(bitmap_bitremap); -/** - * 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_PER_LONG) - return -EINVAL; +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 */ +}; - /* make a mask of the order */ - mask = (1ul << (pages - 1)); +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);