+/* The bitmap for 256 entries is always 32 bytes */
+#define CHAR_BIT_SHIFT 3UL
+#define CHAR_BIT_MASK ((1UL << CHAR_BIT_SHIFT) - 1)
+#if (CHAR_BIT != (1UL << CHAR_BIT_SHIFT))
+#error "char size not supported."
+#endif
+
+#define ULONG_BIT_MASK (CAA_BITS_PER_LONG - 1)
+
+#define JA_BITMAP_BITS JA_ENTRY_PER_NODE
+#define JA_BITMAP_LEN (JA_BITMAP_BITS / CHAR_BIT)
+
+#define __JA_ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
+#define JA_ALIGN(v, align) __JA_ALIGN_MASK(v, (typeof(v)) (align) - 1)
+#define __JA_FLOOR_MASK(v, mask) ((v) & ~(mask))
+#define JA_FLOOR(v, align) __JA_FLOOR_MASK(v, (typeof(v)) (align) - 1)
+
+static
+char *align_ptr_size(char *ptr)
+{
+ return JA_ALIGN(ptr, sizeof(ptr));
+}
+
+static
+struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
+ struct rcu_ja_node *node,
+ uint8_t n)
+{
+ uint8_t nr_child;
+ uint8_t *values;
+ struct rcu_ja_node_flag *pointers;
+ struct rcu_ja_node_flag *ptr;
+ unsigned int i;
+
+ assert(type->type_class == RCU_JA_LINEAR);
+
+ nr_child = node->data[0];
+ cmm_smp_rmb(); /* read nr_child before values */
+ assert(nr_child <= type->max_child);
+ assert(nr_child >= type->min_child);
+
+ values = &node[1];
+ for (i = 0; i < nr_child; i++) {
+ if (values[i] == n)
+ break;
+ }
+ if (i >= nr_child)
+ return NULL;
+ cmm_smp_rmb(); /* read values before pointer */
+ pointers = align_ptr_size(&values[nr_child]);
+ ptr = pointers[i];
+ assert(ja_node_ptr(ptr) != NULL);
+ return ptr;
+}
+
+#if 0
+/*
+ * Count hweight. Expect most bits to be 0. Algorithm from
+ * Wegner (1960): count those in n steps (n being the number of
+ * hot bits). Ref.: Wegner, Peter (1960), "A technique for
+ * counting ones in a binary computer", Communications of the
+ * ACM 3 (5): 322, doi:10.1145/367236.367286.
+ */
+static
+unsigned int ja_hweight_uchar(unsigned char value)
+{
+ unsigned int count = 0;
+
+ for (; value; count++)
+ value &= value - 1;
+ return count;
+}
+#endif //0
+
+#if (CAA_BITS_PER_LONG < 64)
+static
+unsigned int ja_hweight_ulong(unsigned long value)
+{
+ unsigned long r;
+
+ r = value;
+ r = r - ((r >> 1) & 0x55555555);
+ r = (r & 0x33333333) + ((r >> 2) & 0x33333333);
+ r += r >> 4;
+ r &= 0x0F0F0F0F;
+ r += r >> 8;
+ r += r >> 16;
+ r &= 0x000000FF;
+ return r;
+}
+#else /* !(CAA_BITS_PER_LONG < 64) */
+static
+unsigned int ja_hweight_ulong(unsigned long value)
+{
+ unsigned long r;
+
+ r = value;
+ r = r - ((r >> 1) & 0x5555555555555555UL);
+ r = (r & 0x3333333333333333UL) + ((r >> 2) & 0x3333333333333333UL);
+ r += r >> 4;
+ r &= 0x0F0F0F0F0F0F0F0FUL;
+ r += r >> 8;
+ r += r >> 16;
+ r += r >> 32;
+ r &= 0x00000000000000FFUL;
+ return r;
+}
+#endif /* !(BITS_PER_LONG < 64) */
+
+static
+struct rcu_ja_node_flag *ja_bitmap_node_get_nth(const struct rcu_ja_type *type,
+ struct rcu_ja_node *node,
+ uint8_t n)
+{
+ uint8_t *bitmap;
+ uint8_t byte_nr;
+ struct rcu_ja_node_flag *pointers;
+ struct rcu_ja_node_flag *ptr;
+ unsigned int count;
+
+ assert(type->type_class == RCU_JA_BITMAP);