From b5e618181a927210f8be1d3d2249d31904ba358d Mon Sep 17 00:00:00 2001 From: Pavel Emelianov Date: Tue, 8 May 2007 00:30:19 -0700 Subject: Introduce a handy list_first_entry macro There are many places in the kernel where the construction like foo = list_entry(head->next, struct foo_struct, list); are used. The code might look more descriptive and neat if using the macro list_first_entry(head, type, member) \ list_entry((head)->next, type, member) Here is the macro itself and the examples of its usage in the generic code. If it will turn out to be useful, I can prepare the set of patches to inject in into arch-specific code, drivers, networking, etc. Signed-off-by: Pavel Emelianov Signed-off-by: Kirill Korotaev Cc: Randy Dunlap Cc: Andi Kleen Cc: Zach Brown Cc: Davide Libenzi Cc: John McCutchan Cc: Thomas Gleixner Cc: Ingo Molnar Cc: john stultz Cc: Ram Pai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/list.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux') diff --git a/include/linux/list.h b/include/linux/list.h index f9d71eab05e..9202703be2a 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -425,6 +425,17 @@ static inline void list_splice_init_rcu(struct list_head *list, #define list_entry(ptr, type, member) \ container_of(ptr, type, member) +/** + * list_first_entry - get the first 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_first_entry(ptr, type, member) \ + list_entry((ptr)->next, type, member) + /** * list_for_each - iterate over a list * @pos: the &struct list_head to use as a loop cursor. -- cgit v1.2.3