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author | David S. Miller <davem@davemloft.net> | 2016-04-24 01:26:24 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-03 07:22:13 +0300 |
commit | 3bfc4e0ecb9c19a7291156f83ead371d50f63b81 (patch) | |
tree | 0ad168a3b1c2471772241360c6a8d9c0d247ce46 | |
parent | 2d4d5d7afba5e1e05cd0ad191af47e69af118bcb (diff) | |
download | linux-3bfc4e0ecb9c19a7291156f83ead371d50f63b81.tar.xz |
Add hlist_add_tail_rcu() (Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net)
commit 1602f49b58abcb0d34a5f0a29d68e7c1769547aa upstream.
[This commit was a merge, but it added hlist_add_tail_rcu(), which is what we
need in this stable tree, so I've changed the subject to be more descriptive
- gregkh]
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | include/linux/rculist.h | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 372ad5e0dcb8..ca2b76557573 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -405,6 +405,42 @@ static inline void hlist_add_head_rcu(struct hlist_node *n, } /** + * hlist_add_tail_rcu + * @n: the element to add to the hash list. + * @h: the list to add to. + * + * Description: + * Adds the specified element to the specified hlist, + * while permitting racing traversals. + * + * 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(), used to prevent memory-consistency + * problems on Alpha CPUs. Regardless of the type of CPU, the + * list-traversal primitive must be guarded by rcu_read_lock(). + */ +static inline void hlist_add_tail_rcu(struct hlist_node *n, + struct hlist_head *h) +{ + struct hlist_node *i, *last = NULL; + + for (i = hlist_first_rcu(h); i; i = hlist_next_rcu(i)) + last = i; + + if (last) { + n->next = last->next; + n->pprev = &last->next; + rcu_assign_pointer(hlist_next_rcu(last), n); + } else { + hlist_add_head_rcu(n, h); + } +} + +/** * hlist_add_before_rcu * @n: the new element to add to the hash list. * @next: the existing element to add the new element before. |