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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/bitmap.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'lib/bitmap.c')
-rw-r--r--lib/bitmap.c595
1 files changed, 595 insertions, 0 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
new file mode 100644
index 00000000000..d1388a5ce89
--- /dev/null
+++ b/lib/bitmap.c
@@ -0,0 +1,595 @@
+/*
+ * lib/bitmap.c
+ * Helper functions for bitmap.h.
+ *
+ * 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/ctype.h>
+#include <linux/errno.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <asm/uaccess.h>
+
+/*
+ * 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)
+ if (bitmap[k])
+ return 0;
+
+ if (bits % BITS_PER_LONG)
+ if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
+ return 0;
+
+ return 1;
+}
+EXPORT_SYMBOL(__bitmap_empty);
+
+int __bitmap_full(const unsigned long *bitmap, int bits)
+{
+ int k, lim = bits/BITS_PER_LONG;
+ for (k = 0; k < lim; ++k)
+ if (~bitmap[k])
+ return 0;
+
+ if (bits % BITS_PER_LONG)
+ if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
+ return 0;
+
+ return 1;
+}
+EXPORT_SYMBOL(__bitmap_full);
+
+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)
+ 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;
+}
+EXPORT_SYMBOL(__bitmap_equal);
+
+void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
+{
+ int k, lim = bits/BITS_PER_LONG;
+ for (k = 0; k < lim; ++k)
+ dst[k] = ~src[k];
+
+ if (bits % BITS_PER_LONG)
+ dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(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
+ *
+ * Shifting right (dividing) means moving bits in the MS -> LS bit
+ * 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,
+ const unsigned long *src, int shift, int bits)
+{
+ int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
+ int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
+ unsigned long mask = (1UL << left) - 1;
+ for (k = 0; off + k < lim; ++k) {
+ unsigned long upper, lower;
+
+ /*
+ * If shift is not word aligned, take lower rem bits of
+ * word above and make them the top rem bits of result.
+ */
+ if (!rem || off + k + 1 >= lim)
+ upper = 0;
+ else {
+ upper = src[off + k + 1];
+ if (off + k + 1 == lim - 1 && left)
+ upper &= mask;
+ }
+ lower = src[off + k];
+ if (left && off + k == lim - 1)
+ lower &= mask;
+ dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
+ if (left && k == lim - 1)
+ dst[k] &= mask;
+ }
+ if (off)
+ memset(&dst[lim - off], 0, off*sizeof(unsigned long));
+}
+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
+ *
+ * Shifting left (multiplying) means moving bits in the LS -> MS
+ * 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,
+ const unsigned long *src, int shift, int bits)
+{
+ int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
+ int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
+ for (k = lim - off - 1; k >= 0; --k) {
+ unsigned long upper, lower;
+
+ /*
+ * If shift is not word aligned, take upper rem bits of
+ * word below and make them the bottom rem bits of result.
+ */
+ if (rem && k > 0)
+ lower = src[k - 1];
+ else
+ lower = 0;
+ upper = src[k];
+ if (left && k == lim - 1)
+ upper &= (1UL << left) - 1;
+ dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
+ if (left && k + off == lim - 1)
+ dst[k + off] &= (1UL << left) - 1;
+ }
+ if (off)
+ memset(dst, 0, off*sizeof(unsigned long));
+}
+EXPORT_SYMBOL(__bitmap_shift_left);
+
+void __bitmap_and(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_and);
+
+void __bitmap_or(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_or);
+
+void __bitmap_xor(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_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)
+ if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+ return 1;
+ return 0;
+}
+EXPORT_SYMBOL(__bitmap_intersects);
+
+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;
+}
+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]);
+
+ if (bits % BITS_PER_LONG)
+ w += hweight32(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);
+
+/*
+ * Bitmap printing & parsing functions: first version by Bill Irwin,
+ * second version by Paul Jackson, third by Joe Korty.
+ */
+
+#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.
+ * @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
+ *
+ * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
+ * comma-separated sets of eight digits per set.
+ */
+int bitmap_scnprintf(char *buf, unsigned int buflen,
+ const unsigned long *maskp, int nmaskbits)
+{
+ int i, word, bit, len = 0;
+ unsigned long val;
+ const char *sep = "";
+ int chunksz;
+ u32 chunkmask;
+
+ chunksz = nmaskbits & (CHUNKSZ - 1);
+ if (chunksz == 0)
+ chunksz = CHUNKSZ;
+
+ i = roundup_power2(nmaskbits, CHUNKSZ) - CHUNKSZ;
+ for (; i >= 0; i -= CHUNKSZ) {
+ chunkmask = ((1ULL << chunksz) - 1);
+ word = i / BITS_PER_LONG;
+ bit = i % BITS_PER_LONG;
+ val = (maskp[word] >> bit) & chunkmask;
+ len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
+ (chunksz+3)/4, val);
+ chunksz = CHUNKSZ;
+ sep = ",";
+ }
+ return len;
+}
+EXPORT_SYMBOL(bitmap_scnprintf);
+
+/**
+ * bitmap_parse - convert an ASCII hex string into a bitmap.
+ * @buf: pointer to buffer in user space containing string.
+ * @buflen: 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.
+ *
+ * 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
+ * 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 c, old_c, totaldigits, ndigits, nchunks, nbits;
+ u32 chunk;
+
+ bitmap_zero(maskp, nmaskbits);
+
+ nchunks = nbits = totaldigits = c = 0;
+ do {
+ chunk = ndigits = 0;
+
+ /* Get the next chunk of the bitmap */
+ while (ubuflen) {
+ old_c = c;
+ if (get_user(c, ubuf++))
+ return -EFAULT;
+ ubuflen--;
+ 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 the chunk */
+ if (c == '\0' || c == ',')
+ break;
+
+ if (!isxdigit(c))
+ return -EINVAL;
+
+ /*
+ * Make sure there are at least 4 free bits in 'chunk'.
+ * If not, this hexdigit will overflow 'chunk', so
+ * throw an error.
+ */
+ if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
+ return -EOVERFLOW;
+
+ chunk = (chunk << 4) | unhex(c);
+ ndigits++; totaldigits++;
+ }
+ if (ndigits == 0)
+ return -EINVAL;
+ if (nchunks == 0 && chunk == 0)
+ continue;
+
+ __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 == ',');
+
+ return 0;
+}
+EXPORT_SYMBOL(bitmap_parse);
+
+/*
+ * 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
+ * @buf: read nul-terminated user string from this buffer
+ * @mask: 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:
+ * -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_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<<order)
+ *
+ * This is used to allocate a memory region from a bitmap. The idea is
+ * that the region has to be 1<<order sized and 1<<order aligned (this
+ * makes the search algorithm much faster).
+ *
+ * The region is marked as set bits in the bitmap if a free one is
+ * found.
+ *
+ * Returns either beginning of region or negative error
+ */
+int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
+{
+ unsigned long mask;
+ int pages = 1 << order;
+ int i;
+
+ if(pages > BITS_PER_LONG)
+ return -EINVAL;
+
+ /* make a mask of the order */
+ mask = (1ul << (pages - 1));
+ mask += mask - 1;
+
+ /* 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;
+ }
+ }
+ return -ENOMEM;
+}
+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<<order)
+ *
+ * This is the complement to __bitmap_find_free_region and releases
+ * the found region (by clearing it in the bitmap).
+ */
+void bitmap_release_region(unsigned long *bitmap, int pos, int order)
+{
+ int pages = 1 << order;
+ unsigned long mask = (1ul << (pages - 1));
+ int index = pos/BITS_PER_LONG;
+ int offset = pos - (index * BITS_PER_LONG);
+ mask += mask - 1;
+ bitmap[index] &= ~(mask << offset);
+}
+EXPORT_SYMBOL(bitmap_release_region);
+
+int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
+{
+ int pages = 1 << order;
+ unsigned long mask = (1ul << (pages - 1));
+ int index = pos/BITS_PER_LONG;
+ int offset = pos - (index * BITS_PER_LONG);
+
+ /* We don't do regions of pages > 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))
+ return -EBUSY;
+ bitmap[index] |= (mask << offset);
+ return 0;
+}
+EXPORT_SYMBOL(bitmap_allocate_region);