}
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);
/*
/**
* 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
+ * @ubuf: pointer to buffer in user space containing string.
+ * @ubuflen: 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
+ * 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.
*/
/**
* 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
* 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)
{
*
* 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 zero (0).
+ * 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,
*/
static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
{
- int ord = 0;
+ int i, ord;
- if (pos >= 0 && pos < bits) {
- int i;
+ if (pos < 0 || pos >= bits || !test_bit(pos, buf))
+ return -1;
- for (i = find_first_bit(buf, bits);
- i < pos;
- i = find_next_bit(buf, bits, i + 1))
- ord++;
- if (i > pos)
- ord = 0;
+ 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;
}
* @bits: number of valid bit positions in @buf
*
* Map the ordinal offset of bit @ord in @buf to its position in @buf.
- * If @ord is not the ordinal offset of a set bit in @buf, map to zero (0).
+ * 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 valuds will get mapped to 0. When @ord value 3
+ * 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.
*
/**
* bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
- * @src: subset to be remapped
* @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
* 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 does nothing.
+ * 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 the position of
- * the first set bit in @new.
+ * 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.
*
- * The resulting value of @dst will have either the same weight as
- * @src, or less weight in the general case that the mapping wasn't
- * injective due to the weight of @new being less than that of @old.
- * The resulting value of @dst will never have greater weight than
- * that of @src, except perhaps in the case that one of the above
- * conditions was not met and this routine just returned.
- *
* 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 to 12 (the first set bit in @new. So if say @src
- * comes into this routine with bits 1, 5 and 7 set, then @dst should
- * leave with bits 12, 13 and 15 set.
+ * 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 s;
+ int oldbit, w;
- if (bitmap_weight(old, bits) == 0)
- return;
- if (bitmap_weight(new, bits) == 0)
- return;
if (dst == src) /* following doesn't handle inplace remaps */
return;
-
bitmap_zero(dst, bits);
- for (s = find_first_bit(src, bits);
- s < bits;
- s = find_next_bit(src, bits, s + 1)) {
- int x = bitmap_pos_to_ord(old, s, bits);
- int y = bitmap_ord_to_pos(new, x, bits);
- set_bit(y, dst);
+
+ 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
+ * @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
* 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 the position of
- * the first set bit in @new.
+ * 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 to 12 (the first set bit in @new. So if say @oldbit
- * is 5, then this routine returns 13.
+ * 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 x = bitmap_pos_to_ord(old, oldbit, bits);
- return bitmap_ord_to_pos(new, x, 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);
-/**
- * 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)
+/*
+ * 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
*
- * 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).
+ * Can set, verify and/or release a region of bits in a bitmap,
+ * depending on which combination of REG_OP_* flag bits is set.
*
- * The region is marked as set bits in the bitmap if a free one is
- * found.
+ * 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 either beginning of region or negative error
+ * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
+ * Returns 0 in all other cases and reg_ops.
*/
-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;
+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<<order)
+ * 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)
{
- 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);
+ __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)
{
- 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))
+ 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);
git.samba.org / sfrench / cifs-2.6.git / blobdiff