Commit 6beeac76 authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Linus Torvalds

mmu-notifiers: add list_del_init_rcu()

Introduce list_del_init_rcu() and document it.
Signed-off-by: default avatarAndrea Arcangeli <andrea@qumranet.com>
Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Kanoj Sarcar <kanojsarcar@yahoo.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Chris Wright <chrisw@redhat.com>
Cc: Marcelo Tosatti <marcelo@kvack.org>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Izik Eidus <izike@qumranet.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 93686ae8
......@@ -97,6 +97,34 @@ static inline void list_del_rcu(struct list_head *entry)
entry->prev = LIST_POISON2;
}
/**
* hlist_del_init_rcu - deletes entry from hash list with re-initialization
* @n: the element to delete from the hash list.
*
* Note: list_unhashed() on the node return true after this. It is
* useful for RCU based read lockfree traversal if the writer side
* must know if the list entry is still hashed or already unhashed.
*
* In particular, it means that we can not poison the forward pointers
* that may still be used for walking the hash list and we can only
* zero the pprev pointer so list_unhashed() will return true after
* this.
*
* The caller must take whatever precautions are necessary (such as
* holding appropriate locks) to avoid racing with another
* list-mutation primitive, such as hlist_add_head_rcu() or
* hlist_del_rcu(), running on this same list. However, it is
* perfectly legal to run concurrently with the _rcu list-traversal
* primitives, such as hlist_for_each_entry_rcu().
*/
static inline void hlist_del_init_rcu(struct hlist_node *n)
{
if (!hlist_unhashed(n)) {
__hlist_del(n);
n->pprev = NULL;
}
}
/**
* list_replace_rcu - replace old entry by new one
* @old : the element to be replaced
......
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