From 93be3c2eb3371f022ad88acf1ab6bee8e3c38378 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 12 Nov 2013 15:10:03 -0800 Subject: [PATCH] list: introduce list_last_entry(), use list_{first,last}_entry() We already have list_first_entry(), it makes sense to also add list_last_entry() for consistency. And we use both helpers in list_for_each_*(). Signed-off-by: Oleg Nesterov Cc: Eilon Greenstein Cc: Greg Kroah-Hartman Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/list.h | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/include/linux/list.h b/include/linux/list.h index c88a591d1c02..ef9594171062 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -361,6 +361,17 @@ static inline void list_splice_tail_init(struct list_head *list, #define list_first_entry(ptr, type, member) \ list_entry((ptr)->next, type, member) +/** + * list_last_entry - 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 list is expected to be not empty. + */ +#define list_last_entry(ptr, type, member) \ + list_entry((ptr)->prev, type, member) + /** * list_first_entry_or_null - get the first element from a list * @ptr: the list head to take the element from. @@ -432,7 +443,7 @@ static inline void list_splice_tail_init(struct list_head *list, * @member: the name of the list_struct within the struct. */ #define list_for_each_entry(pos, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member); \ + for (pos = list_first_entry(head, typeof(*pos), member); \ &pos->member != (head); \ pos = list_next_entry(pos, member)) @@ -443,7 +454,7 @@ static inline void list_splice_tail_init(struct list_head *list, * @member: the name of the list_struct within the struct. */ #define list_for_each_entry_reverse(pos, head, member) \ - for (pos = list_entry((head)->prev, typeof(*pos), member); \ + for (pos = list_last_entry(head, typeof(*pos), member); \ &pos->member != (head); \ pos = list_prev_entry(pos, member)) @@ -506,7 +517,7 @@ static inline void list_splice_tail_init(struct list_head *list, * @member: the name of the list_struct within the struct. */ #define list_for_each_entry_safe(pos, n, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member), \ + for (pos = list_first_entry(head, typeof(*pos), member), \ n = list_next_entry(pos, member); \ &pos->member != (head); \ pos = n, n = list_next_entry(n, member)) @@ -553,7 +564,7 @@ static inline void list_splice_tail_init(struct list_head *list, * of list entry. */ #define list_for_each_entry_safe_reverse(pos, n, head, member) \ - for (pos = list_entry((head)->prev, typeof(*pos), member), \ + for (pos = list_last_entry(head, typeof(*pos), member), \ n = list_prev_entry(pos, member); \ &pos->member != (head); \ pos = n, n = list_prev_entry(n, member)) -- 2.20.1