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

[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
......@@ -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)
......
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