+/**
+ * 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);
+
+/*
+ * 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.
+ */