From e432947ef5500f0c89ab044e00ee7842d38bdb39 Mon Sep 17 00:00:00 2001 From: Yang Jihong Date: Sat, 9 Jul 2022 09:50:21 +0800 Subject: tools lib: Add list_last_entry_or_null() Add list_last_entry_or_null() to get the last element from a list, returns NULL if the list is empty. Signed-off-by: Yang Jihong Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Paul Clarke Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20220709015033.38326-6-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/include/linux/list.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'tools/include/linux') diff --git a/tools/include/linux/list.h b/tools/include/linux/list.h index b2fc48d5478c..a4dfb6a7cc6a 100644 --- a/tools/include/linux/list.h +++ b/tools/include/linux/list.h @@ -384,6 +384,17 @@ static inline void list_splice_tail_init(struct list_head *list, #define list_first_entry_or_null(ptr, type, member) \ (!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_head 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 -- cgit v1.2.3