From: Jeff Liu Date: Fri, 15 Nov 2013 12:31:15 +0800 Subject: [Cluster-devel] [PATCH 1/6] list: introduce list_last_entry_or_null() Message-ID: <5285A393.8000808@oracle.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: Jie Liu Introduce a trivial helper list_last_entry_or_null() to fetch the last entry from a list, return NULL if the list is empty. Signed-off-by: Jie Liu --- include/linux/list.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/include/linux/list.h b/include/linux/list.h index ef95941..3337249 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -384,6 +384,17 @@ static inline void list_splice_tail_init(struct list_head *list, (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL) /** + * 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_struct within the struct. + * + * Note that if the list is empty, it returns NULL. + */ +#define list_last_entry_or_null(ptr, type, member) \ + (!list_empty(ptr) ? list_last_entry(ptr, type, member) : NULL) + +/** * list_next_entry - get the next element in list * @pos: the type * to cursor * @member: the name of the list_struct within the struct. -- 1.8.3.2