The patch titled
mmu-notifiers: add list_del_init_rcu()
has been added to the -mm tree. Its filename is
mmu-notifiers-add-list_del_init_rcu.patch
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------------------------------------------------------
Subject: mmu-notifiers: add list_del_init_rcu()
From: Andrea Arcangeli <andrea@xxxxxxxxxxxx>
Introduce list_del_init_rcu() and document it.
Signed-off-by: Andrea Arcangeli <andrea@xxxxxxxxxxxx>
Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Christoph Lameter <clameter@xxxxxxx>
Cc: Jack Steiner <steiner@xxxxxxx>
Cc: Robin Holt <holt@xxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Kanoj Sarcar <kanojsarcar@xxxxxxxxx>
Cc: Roland Dreier <rdreier@xxxxxxxxx>
Cc: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Anthony Liguori <aliguori@xxxxxxxxxx>
Cc: Chris Wright <chrisw@xxxxxxxxxx>
Cc: Marcelo Tosatti <marcelo@xxxxxxxxx>
Cc: Eric Dumazet <dada1@xxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Izik Eidus <izike@xxxxxxxxxxxx>
Cc: Anthony Liguori <aliguori@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/list.h | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff -puN include/linux/list.h~mmu-notifiers-add-list_del_init_rcu include/linux/list.h
--- a/include/linux/list.h~mmu-notifiers-add-list_del_init_rcu
+++ a/include/linux/list.h
@@ -523,6 +523,34 @@ static inline void hlist_del_init(struct
}
}
+/**
+ * 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;
+ }
+}
+
static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
struct hlist_node *first = h->first;
_
Patches currently in -mm which might be from andrea@xxxxxxxxxxxx are
linux-next.patch
mmu-notifiers-add-list_del_init_rcu.patch
mm_take_all_locks.patch
mmu-notifier-core.patch
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