diff options
Diffstat (limited to 'lib/bitmap.c')
| -rw-r--r-- | lib/bitmap.c | 438 |
1 files changed, 394 insertions, 44 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 26ebafa8c41d..06f7e4fe8d2d 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -5,11 +5,13 @@ * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ -#include <linux/module.h> +#include <linux/export.h> +#include <linux/thread_info.h> #include <linux/ctype.h> #include <linux/errno.h> #include <linux/bitmap.h> #include <linux/bitops.h> +#include <linux/bug.h> #include <asm/uaccess.h> /* @@ -179,14 +181,16 @@ void __bitmap_shift_left(unsigned long *dst, } EXPORT_SYMBOL(__bitmap_shift_left); -void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, +int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, int bits) { int k; int nr = BITS_TO_LONGS(bits); + unsigned long result = 0; for (k = 0; k < nr; k++) - dst[k] = bitmap1[k] & bitmap2[k]; + result |= (dst[k] = bitmap1[k] & bitmap2[k]); + return result != 0; } EXPORT_SYMBOL(__bitmap_and); @@ -212,14 +216,16 @@ void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, } EXPORT_SYMBOL(__bitmap_xor); -void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, +int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, int bits) { int k; int nr = BITS_TO_LONGS(bits); + unsigned long result = 0; for (k = 0; k < nr; k++) - dst[k] = bitmap1[k] & ~bitmap2[k]; + result |= (dst[k] = bitmap1[k] & ~bitmap2[k]); + return result != 0; } EXPORT_SYMBOL(__bitmap_andnot); @@ -267,14 +273,92 @@ int __bitmap_weight(const unsigned long *bitmap, int bits) } EXPORT_SYMBOL(__bitmap_weight); +void bitmap_set(unsigned long *map, int start, int nr) +{ + unsigned long *p = map + BIT_WORD(start); + const int size = start + nr; + int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); + + while (nr - bits_to_set >= 0) { + *p |= mask_to_set; + nr -= bits_to_set; + bits_to_set = BITS_PER_LONG; + mask_to_set = ~0UL; + p++; + } + if (nr) { + mask_to_set &= BITMAP_LAST_WORD_MASK(size); + *p |= mask_to_set; + } +} +EXPORT_SYMBOL(bitmap_set); + +void bitmap_clear(unsigned long *map, int start, int nr) +{ + unsigned long *p = map + BIT_WORD(start); + const int size = start + nr; + int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); + + while (nr - bits_to_clear >= 0) { + *p &= ~mask_to_clear; + nr -= bits_to_clear; + bits_to_clear = BITS_PER_LONG; + mask_to_clear = ~0UL; + p++; + } + if (nr) { + mask_to_clear &= BITMAP_LAST_WORD_MASK(size); + *p &= ~mask_to_clear; + } +} +EXPORT_SYMBOL(bitmap_clear); + /* - * Bitmap printing & parsing functions: first version by Bill Irwin, + * bitmap_find_next_zero_area - find a contiguous aligned zero area + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @align_mask: Alignment mask for zero area + * + * The @align_mask should be one less than a power of 2; the effect is that + * the bit offset of all zero areas this function finds is multiples of that + * power of 2. A @align_mask of 0 means no alignment is required. + */ +unsigned long bitmap_find_next_zero_area(unsigned long *map, + unsigned long size, + unsigned long start, + unsigned int nr, + unsigned long align_mask) +{ + unsigned long index, end, i; +again: + index = find_next_zero_bit(map, size, start); + + /* Align allocation */ + index = __ALIGN_MASK(index, align_mask); + + end = index + nr; + if (end > size) + return end; + i = find_next_bit(map, end, index); + if (i < end) { + start = i + 1; + goto again; + } + return index; +} +EXPORT_SYMBOL(bitmap_find_next_zero_area); + +/* + * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers, * second version by Paul Jackson, third by Joe Korty. */ #define CHUNKSZ 32 #define nbits_to_hold_value(val) fls(val) -#define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10)) #define BASEDEC 10 /* fancier cpuset lists input in decimal */ /** @@ -285,7 +369,8 @@ EXPORT_SYMBOL(__bitmap_weight); * @nmaskbits: size of bitmap, in bits * * Exactly @nmaskbits bits are displayed. Hex digits are grouped into - * comma-separated sets of eight digits per set. + * comma-separated sets of eight digits per set. Returns the number of + * characters which were written to *buf, excluding the trailing \0. */ int bitmap_scnprintf(char *buf, unsigned int buflen, const unsigned long *maskp, int nmaskbits) @@ -337,7 +422,7 @@ int __bitmap_parse(const char *buf, unsigned int buflen, { int c, old_c, totaldigits, ndigits, nchunks, nbits; u32 chunk; - const char __user *ubuf = buf; + const char __user __force *ubuf = (const char __user __force *)buf; bitmap_zero(maskp, nmaskbits); @@ -381,7 +466,7 @@ int __bitmap_parse(const char *buf, unsigned int buflen, if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1)) return -EOVERFLOW; - chunk = (chunk << 4) | unhex(c); + chunk = (chunk << 4) | hex_to_bin(c); ndigits++; totaldigits++; } if (ndigits == 0) @@ -402,7 +487,7 @@ int __bitmap_parse(const char *buf, unsigned int buflen, EXPORT_SYMBOL(__bitmap_parse); /** - * bitmap_parse_user() + * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap * * @ubuf: pointer to user buffer containing string. * @ulen: buffer size in bytes. If string is smaller than this @@ -422,7 +507,9 @@ int bitmap_parse_user(const char __user *ubuf, { if (!access_ok(VERIFY_READ, ubuf, ulen)) return -EFAULT; - return __bitmap_parse((const char *)ubuf, ulen, 1, maskp, nmaskbits); + return __bitmap_parse((const char __force *)ubuf, + ulen, 1, maskp, nmaskbits); + } EXPORT_SYMBOL(bitmap_parse_user); @@ -431,8 +518,8 @@ EXPORT_SYMBOL(bitmap_parse_user); * * 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. + * comma-prefix. Return len of what was written to *buf, excluding the + * trailing \0. */ static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len) { @@ -458,9 +545,8 @@ static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len) * 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. + * The return value is the number of characters which were written to *buf + * excluding the trailing '\0', as per ISO C99's scnprintf. */ int bitmap_scnlistprintf(char *buf, unsigned int buflen, const unsigned long *maskp, int nmaskbits) @@ -469,6 +555,10 @@ 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; @@ -483,8 +573,11 @@ int bitmap_scnlistprintf(char *buf, unsigned int buflen, EXPORT_SYMBOL(bitmap_scnlistprintf); /** - * bitmap_parselist - convert list format ASCII string to bitmap - * @bp: read nul-terminated user string from this buffer + * __bitmap_parselist - convert list format ASCII string to bitmap + * @buf: read nul-terminated user string from this buffer + * @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: write resulting mask here * @nmaskbits: number of bits in mask to be written * @@ -499,20 +592,63 @@ EXPORT_SYMBOL(bitmap_scnlistprintf); * %-EINVAL: invalid character in string * %-ERANGE: bit number specified too large for mask */ -int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) +static int __bitmap_parselist(const char *buf, unsigned int buflen, + int is_user, unsigned long *maskp, + int nmaskbits) { unsigned a, b; + int c, old_c, totaldigits; + const char __user __force *ubuf = (const char __user __force *)buf; + int exp_digit, in_range; + totaldigits = c = 0; bitmap_zero(maskp, nmaskbits); do { - if (!isdigit(*bp)) - return -EINVAL; - b = a = simple_strtoul(bp, (char **)&bp, BASEDEC); - if (*bp == '-') { - bp++; - if (!isdigit(*bp)) + exp_digit = 1; + in_range = 0; + a = b = 0; + + /* Get the next cpu# or a range of cpu#'s */ + while (buflen) { + old_c = c; + if (is_user) { + if (__get_user(c, ubuf++)) + return -EFAULT; + } else + c = *buf++; + buflen--; + if (isspace(c)) + continue; + + /* + * If the last character was a space and the current + * character isn't '\0', we've got embedded whitespace. + * This is a no-no, so throw an error. + */ + if (totaldigits && c && isspace(old_c)) + return -EINVAL; + + /* A '\0' or a ',' signal the end of a cpu# or range */ + if (c == '\0' || c == ',') + break; + + if (c == '-') { + if (exp_digit || in_range) + return -EINVAL; + b = 0; + in_range = 1; + exp_digit = 1; + continue; + } + + if (!isdigit(c)) return -EINVAL; - b = simple_strtoul(bp, (char **)&bp, BASEDEC); + + b = b * 10 + (c - '0'); + if (!in_range) + a = b; + exp_digit = 0; + totaldigits++; } if (!(a <= b)) return -EINVAL; @@ -522,15 +658,54 @@ int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) set_bit(a, maskp); a++; } - if (*bp == ',') - bp++; - } while (*bp != '\0' && *bp != '\n'); + } while (buflen && c == ','); return 0; } + +int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits) +{ + char *nl = strchr(bp, '\n'); + int len; + + if (nl) + len = nl - bp; + else + len = strlen(bp); + + return __bitmap_parselist(bp, len, 0, maskp, nmaskbits); +} EXPORT_SYMBOL(bitmap_parselist); + /** - * bitmap_pos_to_ord(buf, pos, bits) + * bitmap_parselist_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_parselist(), 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_parselist_user(const char __user *ubuf, + unsigned int ulen, unsigned long *maskp, + int nmaskbits) +{ + if (!access_ok(VERIFY_READ, ubuf, ulen)) + return -EFAULT; + return __bitmap_parselist((const char __force *)ubuf, + ulen, 1, maskp, nmaskbits); +} +EXPORT_SYMBOL(bitmap_parselist_user); + + +/** + * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap * @buf: pointer to a bitmap * @pos: a bit position in @buf (0 <= @pos < @bits) * @bits: number of valid bit positions in @buf @@ -566,7 +741,7 @@ static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits) } /** - * bitmap_ord_to_pos(buf, ord, bits) + * bitmap_ord_to_pos - find position of n-th set bit in bitmap * @buf: pointer to bitmap * @ord: ordinal bit position (n-th set bit, n >= 0) * @bits: number of valid bit positions in @buf @@ -583,7 +758,7 @@ static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits) * * 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 bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits) { int pos = 0; @@ -644,10 +819,9 @@ void bitmap_remap(unsigned long *dst, const unsigned long *src, 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)) { + for_each_set_bit(oldbit, src, bits) { int n = bitmap_pos_to_ord(old, oldbit, bits); + if (n < 0 || w == 0) set_bit(oldbit, dst); /* identity map */ else @@ -694,6 +868,160 @@ int bitmap_bitremap(int oldbit, const unsigned long *old, } EXPORT_SYMBOL(bitmap_bitremap); +/** + * bitmap_onto - translate one bitmap relative to another + * @dst: resulting translated bitmap + * @orig: original untranslated bitmap + * @relmap: bitmap relative to which translated + * @bits: number of bits in each of these bitmaps + * + * Set the n-th bit of @dst iff there exists some m such that the + * n-th bit of @relmap is set, the m-th bit of @orig is set, and + * the n-th bit of @relmap is also the m-th _set_ bit of @relmap. + * (If you understood the previous sentence the first time your + * read it, you're overqualified for your current job.) + * + * In other words, @orig is mapped onto (surjectively) @dst, + * using the the map { <n, m> | the n-th bit of @relmap is the + * m-th set bit of @relmap }. + * + * Any set bits in @orig above bit number W, where W is the + * weight of (number of set bits in) @relmap are mapped nowhere. + * In particular, if for all bits m set in @orig, m >= W, then + * @dst will end up empty. In situations where the possibility + * of such an empty result is not desired, one way to avoid it is + * to use the bitmap_fold() operator, below, to first fold the + * @orig bitmap over itself so that all its set bits x are in the + * range 0 <= x < W. The bitmap_fold() operator does this by + * setting the bit (m % W) in @dst, for each bit (m) set in @orig. + * + * Example [1] for bitmap_onto(): + * Let's say @relmap has bits 30-39 set, and @orig has bits + * 1, 3, 5, 7, 9 and 11 set. Then on return from this routine, + * @dst will have bits 31, 33, 35, 37 and 39 set. + * + * When bit 0 is set in @orig, it means turn on the bit in + * @dst corresponding to whatever is the first bit (if any) + * that is turned on in @relmap. Since bit 0 was off in the + * above example, we leave off that bit (bit 30) in @dst. + * + * When bit 1 is set in @orig (as in the above example), it + * means turn on the bit in @dst corresponding to whatever + * is the second bit that is turned on in @relmap. The second + * bit in @relmap that was turned on in the above example was + * bit 31, so we turned on bit 31 in @dst. + * + * Similarly, we turned on bits 33, 35, 37 and 39 in @dst, + * because they were the 4th, 6th, 8th and 10th set bits + * set in @relmap, and the 4th, 6th, 8th and 10th bits of + * @orig (i.e. bits 3, 5, 7 and 9) were also set. + * + * When bit 11 is set in @orig, it means turn on the bit in + * @dst corresponding to whatever is the twelfth bit that is + * turned on in @relmap. In the above example, there were + * only ten bits turned on in @relmap (30..39), so that bit + * 11 was set in @orig had no affect on @dst. + * + * Example [2] for bitmap_fold() + bitmap_onto(): + * Let's say @relmap has these ten bits set: + * 40 41 42 43 45 48 53 61 74 95 + * (for the curious, that's 40 plus the first ten terms of the + * Fibonacci sequence.) + * + * Further lets say we use the following code, invoking + * bitmap_fold() then bitmap_onto, as suggested above to + * avoid the possitility of an empty @dst result: + * + * unsigned long *tmp; // a temporary bitmap's bits + * + * bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits); + * bitmap_onto(dst, tmp, relmap, bits); + * + * Then this table shows what various values of @dst would be, for + * various @orig's. I list the zero-based positions of each set bit. + * The tmp column shows the intermediate result, as computed by + * using bitmap_fold() to fold the @orig bitmap modulo ten + * (the weight of @relmap). + * + * @orig tmp @dst + * 0 0 40 + * 1 1 41 + * 9 9 95 + * 10 0 40 (*) + * 1 3 5 7 1 3 5 7 41 43 48 61 + * 0 1 2 3 4 0 1 2 3 4 40 41 42 43 45 + * 0 9 18 27 0 9 8 7 40 61 74 95 + * 0 10 20 30 0 40 + * 0 11 22 33 0 1 2 3 40 41 42 43 + * 0 12 24 36 0 2 4 6 40 42 45 53 + * 78 102 211 1 2 8 41 42 74 (*) + * + * (*) For these marked lines, if we hadn't first done bitmap_fold() + * into tmp, then the @dst result would have been empty. + * + * If either of @orig or @relmap is empty (no set bits), then @dst + * will be returned empty. + * + * If (as explained above) the only set bits in @orig are in positions + * m where m >= W, (where W is the weight of @relmap) then @dst will + * once again be returned empty. + * + * All bits in @dst not set by the above rule are cleared. + */ +void bitmap_onto(unsigned long *dst, const unsigned long *orig, + const unsigned long *relmap, int bits) +{ + int n, m; /* same meaning as in above comment */ + + if (dst == orig) /* following doesn't handle inplace mappings */ + return; + bitmap_zero(dst, bits); + + /* + * The following code is a more efficient, but less + * obvious, equivalent to the loop: + * for (m = 0; m < bitmap_weight(relmap, bits); m++) { + * n = bitmap_ord_to_pos(orig, m, bits); + * if (test_bit(m, orig)) + * set_bit(n, dst); + * } + */ + + m = 0; + for_each_set_bit(n, relmap, bits) { + /* m == bitmap_pos_to_ord(relmap, n, bits) */ + if (test_bit(m, orig)) + set_bit(n, dst); + m++; + } +} +EXPORT_SYMBOL(bitmap_onto); + +/** + * bitmap_fold - fold larger bitmap into smaller, modulo specified size + * @dst: resulting smaller bitmap + * @orig: original larger bitmap + * @sz: specified size + * @bits: number of bits in each of these bitmaps + * + * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst. + * Clear all other bits in @dst. See further the comment and + * Example [2] for bitmap_onto() for why and how to use this. + */ +void bitmap_fold(unsigned long *dst, const unsigned long *orig, + int sz, int bits) +{ + int oldbit; + + if (dst == orig) /* following doesn't handle inplace mappings */ + return; + bitmap_zero(dst, bits); + + for_each_set_bit(oldbit, orig, bits) + set_bit(oldbit % sz, dst); +} +EXPORT_SYMBOL(bitmap_fold); + /* * Common code for bitmap_*_region() routines. * bitmap: array of unsigned longs corresponding to the bitmap @@ -786,15 +1114,15 @@ done: */ int bitmap_find_free_region(unsigned long *bitmap, int bits, int order) { - int pos; /* scans bitmap by regions of size order */ + int pos, end; /* 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; + for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) { + if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) + continue; + __reg_op(bitmap, pos, order, REG_OP_ALLOC); + return pos; + } + return -ENOMEM; } EXPORT_SYMBOL(bitmap_find_free_region); @@ -834,3 +1162,25 @@ int bitmap_allocate_region(unsigned long *bitmap, int pos, int order) return 0; } EXPORT_SYMBOL(bitmap_allocate_region); + +/** + * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order. + * @dst: destination buffer + * @src: bitmap to copy + * @nbits: number of bits in the bitmap + * + * Require nbits % BITS_PER_LONG == 0. + */ +void bitmap_copy_le(void *dst, const unsigned long *src, int nbits) +{ + unsigned long *d = dst; + int i; + + for (i = 0; i < nbits/BITS_PER_LONG; i++) { + if (BITS_PER_LONG == 64) + d[i] = cpu_to_le64(src[i]); + else + d[i] = cpu_to_le32(src[i]); + } +} +EXPORT_SYMBOL(bitmap_copy_le); |