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Commit 54e73770 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

[PATCH] list: introduce list_replace() helper 



list_replace() is similar to list_replace_rcu(), but unlike
list_replace_rcu() it

	could be used when list_empty(old) == 1

	doesn't use barriers

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent cb259f07

include/linux/list.h

+23 −0
Original line number Diff line number Diff line
@@ -197,12 +197,35 @@ static inline void list_del_rcu(struct list_head *entry) 
	entry->prev = LIST_POISON2;

}



/**

 * list_replace - replace old entry by new one

 * @old : the element to be replaced

 * @new : the new element to insert

 * Note: if 'old' was empty, it will be overwritten.

 */

static inline void list_replace(struct list_head *old,

				struct list_head *new)

{

	new->next = old->next;

	new->next->prev = new;

	new->prev = old->prev;

	new->prev->next = new;

}



static inline void list_replace_init(struct list_head *old,

					struct list_head *new)

{

	list_replace(old, new);

	INIT_LIST_HEAD(old);

}



/*

 * list_replace_rcu - replace old entry by new one

 * @old : the element to be replaced

 * @new : the new element to insert

 *

 * The old entry will be replaced with the new entry atomically.

 * Note: 'old' should not be empty.

 */

static inline void list_replace_rcu(struct list_head *old,

				struct list_head *new)