Commit e432947e authored by Yang Jihong's avatar Yang Jihong Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarYang Jihong <yangjihong1@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220709015033.38326-6-yangjihong1@huawei.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 97179d9d

tools/include/linux/list.h

+11 −0
Original line number Diff line number Diff line
@@ -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