diff options
Diffstat (limited to 'include/linux/rculist_nulls.h')
| -rw-r--r-- | include/linux/rculist_nulls.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h index 1c33dd7da4a7..4ae95f7e8597 100644 --- a/include/linux/rculist_nulls.h +++ b/include/linux/rculist_nulls.h @@ -98,6 +98,45 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n, if (!is_a_nulls(first)) first->pprev = &n->next; } + +/** + * 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 end of the specified hlist_nulls, + * while permitting racing traversals. NOTE: tail insertion requires + * list traversal. + * + * 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; + + for (i = hlist_nulls_first_rcu(h); !is_a_nulls(i); + i = hlist_nulls_next_rcu(i)) + last = i; + + if (last) { + n->next = last->next; + n->pprev = &last->next; + rcu_assign_pointer(hlist_nulls_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. |