Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ff3c44e6 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

rcu: Add list_next_or_null_rcu



This is a convenience function that returns the next entry in an RCU
list or NULL if at the end of the list.

Signed-off-by: default avatarTom Herbert <tom@herbertland.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 26e90931
Loading
Loading
Loading
Loading
+21 −0
Original line number Diff line number Diff line
@@ -318,6 +318,27 @@ static inline void list_splice_tail_init_rcu(struct list_head *list,
	likely(__ptr != __next) ? list_entry_rcu(__next, type, member) : NULL; \
})

/**
 * list_next_or_null_rcu - get the first element from a list
 * @head:	the head for the list.
 * @ptr:        the list head to take the next 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 ptr is at the end of the list, NULL is returned.
 *
 * This primitive may safely run concurrently with the _rcu list-mutation
 * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
 */
#define list_next_or_null_rcu(head, ptr, type, member) \
({ \
	struct list_head *__head = (head); \
	struct list_head *__ptr = (ptr); \
	struct list_head *__next = READ_ONCE(__ptr->next); \
	likely(__next != __head) ? list_entry_rcu(__next, type, \
						  member) : NULL; \
})

/**
 * list_for_each_entry_rcu	-	iterate over rcu list of given type
 * @pos:	the type * to use as a loop cursor.