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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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>

authored by

Andrea Arcangeli and committed by
Linus Torvalds 6beeac76 93686ae8

+28
+28
include/linux/rculist.h
··· 98 98 } 99 99 100 100 /** 101 + * hlist_del_init_rcu - deletes entry from hash list with re-initialization 102 + * @n: the element to delete from the hash list. 103 + * 104 + * Note: list_unhashed() on the node return true after this. It is 105 + * useful for RCU based read lockfree traversal if the writer side 106 + * must know if the list entry is still hashed or already unhashed. 107 + * 108 + * In particular, it means that we can not poison the forward pointers 109 + * that may still be used for walking the hash list and we can only 110 + * zero the pprev pointer so list_unhashed() will return true after 111 + * this. 112 + * 113 + * The caller must take whatever precautions are necessary (such as 114 + * holding appropriate locks) to avoid racing with another 115 + * list-mutation primitive, such as hlist_add_head_rcu() or 116 + * hlist_del_rcu(), running on this same list. However, it is 117 + * perfectly legal to run concurrently with the _rcu list-traversal 118 + * primitives, such as hlist_for_each_entry_rcu(). 119 + */ 120 + static inline void hlist_del_init_rcu(struct hlist_node *n) 121 + { 122 + if (!hlist_unhashed(n)) { 123 + __hlist_del(n); 124 + n->pprev = NULL; 125 + } 126 + } 127 + 128 + /** 101 129 * list_replace_rcu - replace old entry by new one 102 130 * @old : the element to be replaced 103 131 * @new : the new element to insert