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author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-23 06:59:19 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-23 06:59:19 -0500 |
commit | 749e4121d6ee7fd4495779730fbc6ae800d0317c (patch) | |
tree | 9270ebabd9e3b57ef0427495ec9228f52454b608 /include/linux/rculist_nulls.h | |
parent | tty: serial: 21285: stop using the unused[] variable from struct uart_port (diff) | |
parent | Linux 5.5-rc3 (diff) | |
download | linux-dev-749e4121d6ee7fd4495779730fbc6ae800d0317c.tar.xz linux-dev-749e4121d6ee7fd4495779730fbc6ae800d0317c.zip |
Merge 5.5-rc3 into tty-next
We need the tty/serial fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/rculist_nulls.h')
-rw-r--r-- | include/linux/rculist_nulls.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h index bc8206a8f30e..61974c4c566b 100644 --- a/include/linux/rculist_nulls.h +++ b/include/linux/rculist_nulls.h @@ -101,6 +101,43 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n, } /** + * hlist_nulls_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_nulls, + * 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_nulls_add_head_rcu() + * or hlist_nulls_del_rcu(), running on this same list. + * However, it is perfectly legal to run concurrently with + * the _rcu list-traversal primitives, such as + * hlist_nulls_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_nulls_add_tail_rcu(struct hlist_nulls_node *n, + struct hlist_nulls_head *h) +{ + struct hlist_nulls_node *i, *last = NULL; + + /* Note: write side code, so rcu accessors are not needed. */ + for (i = h->first; !is_a_nulls(i); i = i->next) + last = i; + + if (last) { + n->next = last->next; + n->pprev = &last->next; + rcu_assign_pointer(hlist_next_rcu(last), n); + } else { + hlist_nulls_add_head_rcu(n, h); + } +} + +/** * hlist_nulls_for_each_entry_rcu - iterate over rcu list of given type * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_nulls_node to use as a loop cursor. |