+ list_for_each_safe_off(h, i, nxt, list_off_var_(i, member))
+
+/**
+ * list_next - get the next entry in a list
+ * @h: the list_head
+ * @i: a pointer to an entry in the list.
+ * @member: the list_node member of the structure
+ *
+ * If @i was the last entry in the list, returns NULL.
+ *
+ * Example:
+ * struct child *second;
+ * second = list_next(&parent->children, first, list);
+ * if (!second)
+ * printf("No second child!\n");
+ */
+#define list_next(h, i, member) \
+ ((list_typeof(i))list_entry_or_null(list_debug(h, \
+ __FILE__ ":" stringify(__LINE__)), \
+ (i)->member.next, \
+ list_off_var_((i), member)))
+
+/**
+ * list_prev - get the previous entry in a list
+ * @h: the list_head
+ * @i: a pointer to an entry in the list.
+ * @member: the list_node member of the structure
+ *
+ * If @i was the first entry in the list, returns NULL.
+ *
+ * Example:
+ * first = list_prev(&parent->children, second, list);
+ * if (!first)
+ * printf("Can't go back to first child?!\n");
+ */
+#define list_prev(h, i, member) \
+ ((list_typeof(i))list_entry_or_null(list_debug(h, \
+ __FILE__ ":" stringify(__LINE__)), \
+ (i)->member.prev, \
+ list_off_var_((i), member)))
+
+/**
+ * list_append_list - empty one list onto the end of another.
+ * @to: the list to append into
+ * @from: the list to empty.
+ *
+ * This takes the entire contents of @from and moves it to the end of
+ * @to. After this @from will be empty.
+ *
+ * Example:
+ * struct list_head adopter;
+ *
+ * list_append_list(&adopter, &parent->children);
+ * assert(list_empty(&parent->children));
+ * parent->num_children = 0;
+ */
+#define list_append_list(t, f) list_append_list_(t, f, \
+ __FILE__ ":" stringify(__LINE__))
+static inline void list_append_list_(struct list_head *to,
+ struct list_head *from,
+ const char *abortstr)
+{
+ struct list_node *from_tail = list_debug(from, abortstr)->n.prev;
+ struct list_node *to_tail = list_debug(to, abortstr)->n.prev;
+
+ /* Sew in head and entire list. */
+ to->n.prev = from_tail;
+ from_tail->next = &to->n;
+ to_tail->next = &from->n;
+ from->n.prev = to_tail;
+
+ /* Now remove head. */
+ list_del(&from->n);
+ list_head_init(from);
+}
+
+/**
+ * list_prepend_list - empty one list into the start of another.
+ * @to: the list to prepend into
+ * @from: the list to empty.
+ *
+ * This takes the entire contents of @from and moves it to the start
+ * of @to. After this @from will be empty.
+ *
+ * Example:
+ * list_prepend_list(&adopter, &parent->children);
+ * assert(list_empty(&parent->children));
+ * parent->num_children = 0;
+ */
+#define list_prepend_list(t, f) list_prepend_list_(t, f, LIST_LOC)
+static inline void list_prepend_list_(struct list_head *to,
+ struct list_head *from,
+ const char *abortstr)
+{
+ struct list_node *from_tail = list_debug(from, abortstr)->n.prev;
+ struct list_node *to_head = list_debug(to, abortstr)->n.next;
+
+ /* Sew in head and entire list. */
+ to->n.next = &from->n;
+ from->n.prev = &to->n;
+ to_head->prev = from_tail;
+ from_tail->next = to_head;
+
+ /* Now remove head. */
+ list_del(&from->n);
+ list_head_init(from);
+}
+
+/**
+ * list_for_each_off - iterate through a list of memory regions.
+ * @h: the list_head
+ * @i: the pointer to a memory region wich contains list node data.
+ * @off: offset(relative to @i) at which list node data resides.
+ *
+ * This is a low-level wrapper to iterate @i over the entire list, used to
+ * implement all oher, more high-level, for-each constructs. It's a for loop,
+ * so you can break and continue as normal.
+ *
+ * WARNING! Being the low-level macro that it is, this wrapper doesn't know
+ * nor care about the type of @i. The only assumtion made is that @i points
+ * to a chunk of memory that at some @offset, relative to @i, contains a
+ * properly filled `struct node_list' which in turn contains pointers to
+ * memory chunks and it's turtles all the way down. Whith all that in mind
+ * remember that given the wrong pointer/offset couple this macro will
+ * happilly churn all you memory untill SEGFAULT stops it, in other words
+ * caveat emptor.
+ *
+ * It is worth mentioning that one of legitimate use-cases for that wrapper
+ * is operation on opaque types with known offset for `struct list_node'
+ * member(preferably 0), because it allows you not to disclose the type of
+ * @i.
+ *
+ * Example:
+ * list_for_each_off(&parent->children, child,
+ * offsetof(struct child, list))
+ * printf("Name: %s\n", child->name);
+ */
+#define list_for_each_off(h, i, off) \
+ for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.next, \
+ (off)); \
+ list_node_from_off_((void *)i, (off)) != &(h)->n; \
+ i = list_node_to_off_(list_node_from_off_((void *)i, (off))->next, \
+ (off)))
+
+/**
+ * list_for_each_safe_off - iterate through a list of memory regions, maybe
+ * during deletion
+ * @h: the list_head
+ * @i: the pointer to a memory region wich contains list node data.
+ * @nxt: the structure containing the list_node
+ * @off: offset(relative to @i) at which list node data resides.
+ *
+ * For details see `list_for_each_off' and `list_for_each_safe'
+ * descriptions.
+ *
+ * Example:
+ * list_for_each_safe_off(&parent->children, child,
+ * next, offsetof(struct child, list))
+ * printf("Name: %s\n", child->name);
+ */
+#define list_for_each_safe_off(h, i, nxt, off) \
+ for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.next, \
+ (off)), \
+ nxt = list_node_to_off_(list_node_from_off_(i, (off))->next, \
+ (off)); \
+ list_node_from_off_(i, (off)) != &(h)->n; \
+ i = nxt, \
+ nxt = list_node_to_off_(list_node_from_off_(i, (off))->next, \
+ (off)))
+
+
+/* Other -off variants. */
+#define list_entry_off(n, type, off) \
+ ((type *)list_node_from_off_((n), (off)))
+
+#define list_head_off(h, type, off) \
+ ((type *)list_head_off((h), (off)))
+
+#define list_tail_off(h, type, off) \
+ ((type *)list_tail_((h), (off)))
+
+#define list_add_off(h, n, off) \
+ list_add((h), list_node_from_off_((n), (off)))
+
+#define list_del_off(n, off) \
+ list_del(list_node_from_off_((n), (off)))
+
+#define list_del_from_off(h, n, off) \
+ list_del_from(h, list_node_from_off_((n), (off)))
+
+/* Offset helper functions so we only single-evaluate. */
+static inline void *list_node_to_off_(struct list_node *node, size_t off)
+{
+ return (void *)((char *)node - off);
+}
+static inline struct list_node *list_node_from_off_(void *ptr, size_t off)
+{
+ return (struct list_node *)((char *)ptr + off);
+}
+
+/* Get the offset of the member, but make sure it's a list_node. */
+#define list_off_(type, member) \
+ (container_off(type, member) + \
+ check_type(((type *)0)->member, struct list_node))
+
+#define list_off_var_(var, member) \
+ (container_off_var(var, member) + \
+ check_type(var->member, struct list_node))
+
+#if HAVE_TYPEOF
+#define list_typeof(var) typeof(var)
+#else
+#define list_typeof(var) void *
+#endif
+
+/* Returns member, or NULL if at end of list. */
+static inline void *list_entry_or_null(const struct list_head *h,
+ const struct list_node *n,
+ size_t off)
+{
+ if (n == &h->n)
+ return NULL;
+ return (char *)n - off;
+}