diff options
Diffstat (limited to 'include/linux/list.h')
| -rw-r--r-- | include/linux/list.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/include/linux/list.h b/include/linux/list.h index e7e28afd28f8..5bfda2f91fca 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -20,8 +20,16 @@ * using the generic single-entry routines. */ +/** + * LIST_HEAD_INIT - initialize a &struct list_head's links to point to itself + * @name: name of the list_head + */ #define LIST_HEAD_INIT(name) { &(name), &(name) } +/** + * LIST_HEAD - definition of a &struct list_head with initialization values + * @name: name of the list_head + */ #define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name) @@ -637,6 +645,20 @@ static inline void list_splice_tail_init(struct list_head *list, }) /** + * list_last_entry_or_null - get the last 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_head within the struct. + * + * Note that if the list is empty, it returns NULL. + */ +#define list_last_entry_or_null(ptr, type, member) ({ \ + struct list_head *head__ = (ptr); \ + struct list_head *pos__ = READ_ONCE(head__->prev); \ + pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ +}) + +/** * list_next_entry - get the next element in list * @pos: the type * to cursor * @member: the name of the list_head within the struct. |