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author | Andrea Arcangeli <andrea@qumranet.com> | 2008-07-28 22:46:22 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-28 23:30:20 (GMT) |
commit | 6beeac76f5f96590fb751af5e138fbc3f62e8460 (patch) | |
tree | 530b768655b63893f019204fe4f9b8405db07ac2 /include/linux/rculist.h | |
parent | 93686ae8357c1b1e37e8dfc96547f807e7a93b4b (diff) | |
download | linux-fsl-qoriq-6beeac76f5f96590fb751af5e138fbc3f62e8460.tar.xz |
mmu-notifiers: add list_del_init_rcu()
Introduce list_del_init_rcu() and document it.
Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>
Acked-by: Linus 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/rculist.h')
-rw-r--r-- | include/linux/rculist.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h index b0f39be..eb4443c 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -98,6 +98,34 @@ static inline void list_del_rcu(struct list_head *entry) } /** + * 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 * @new : the new element to insert |