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list: introduce list_first_entry_or_null 

non-rcu variant of list_first_or_null_rcu

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Pirko 2013-05-29 05:02:56 +00:00 committed by David S. Miller
parent e4e8536f65
commit 6d7581e62f
1 changed files with 11 additions and 0 deletions
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11
include/linux/list.h
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@ -361,6 +361,17 @@ static inline void list_splice_tail_init(struct list_head *list,
#define list_first_entry(ptr, type, member) \ #define list_first_entry(ptr, type, member) \
list_entry((ptr)->next, type, member) list_entry((ptr)->next, type, member)
/**
* list_first_entry_or_null - 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 if the list is empty, it returns NULL.
*/
#define list_first_entry_or_null(ptr, type, member) \
(!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
/** /**
* list_for_each - iterate over a list * list_for_each - iterate over a list
* @pos: the &struct list_head to use as a loop cursor. * @pos: the &struct list_head to use as a loop cursor.