diff --git a/list.h b/list.h index 50f46193..db7a58c7 100644 --- a/list.h +++ b/list.h @@ -223,18 +223,18 @@ static inline int list_empty_careful(const struct list_head *head) return (next == head) && (next == head->prev); } -static inline void __list_splice(struct list_head *list, - struct list_head *head) +static inline void __list_splice(const struct list_head *list, + struct list_head *prev, + struct list_head *next) { struct list_head *first = list->next; struct list_head *last = list->prev; - struct list_head *at = head->next; - first->prev = head; - head->next = first; + first->prev = prev; + prev->next = first; - last->next = at; - at->prev = last; + last->next = next; + next->prev = last; } /** @@ -245,7 +245,19 @@ static inline void __list_splice(struct list_head *list, static inline void list_splice(struct list_head *list, struct list_head *head) { if (!list_empty(list)) - __list_splice(list, head); + __list_splice(list, head, head->next); +} + +/** + * list_splice_tail - join two lists, each list being a queue + * @list: the new list to add. + * @head: the place to add it in the first list. + */ +static inline void list_splice_tail(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) + __list_splice(list, head->prev, head); } /** @@ -259,7 +271,24 @@ static inline void list_splice_init(struct list_head *list, struct list_head *head) { if (!list_empty(list)) { - __list_splice(list, head); + __list_splice(list, head, head->next); + INIT_LIST_HEAD(list); + } +} + +/** + * list_splice_tail_init - join two lists and reinitialise the emptied list + * @list: the new list to add. + * @head: the place to add it in the first list. + * + * Each of the lists is a queue. + * The list at @list is reinitialised + */ +static inline void list_splice_tail_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head->prev, head); INIT_LIST_HEAD(list); } } @@ -273,6 +302,27 @@ static inline void list_splice_init(struct list_head *list, #define list_entry(ptr, type, member) \ container_of(ptr, type, member) +/** + * list_first_entry - get the first element from a list + * @ptr: the list head to take the element from. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_struct within the struct. + * + * Note, that list is expected to be not empty. + */ +#define list_first_entry(ptr, type, member) \ + list_entry((ptr)->next, type, member) + +/** + * list_next_entry - get the next element from a list + * @ptr: the list head to take the element from. + * @member: the name of the list_struct within the struct. + * + * Note, that next is expected to be not null. + */ +#define list_next_entry(ptr, member) \ + list_entry((ptr)->member.next, typeof(*ptr), member) + /** * list_for_each - iterate over a list * @pos: the &struct list_head to use as a loop cursor.