diff options
Diffstat (limited to 'include/linux/rculist.h')
| -rw-r--r-- | include/linux/rculist.h | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 4106721c4e5e..45a0a9e81478 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -19,6 +19,21 @@ */ /* + * INIT_LIST_HEAD_RCU - Initialize a list_head visible to RCU readers + * @list: list to be initialized + * + * You should instead use INIT_LIST_HEAD() for normal initialization and + * cleanup tasks, when readers have no access to the list being initialized. + * However, if the list being initialized is visible to readers, you + * need to keep the compiler from being too mischievous. + */ +static inline void INIT_LIST_HEAD_RCU(struct list_head *list) +{ + ACCESS_ONCE(list->next) = list; + ACCESS_ONCE(list->prev) = list; +} + +/* * return the ->next pointer of a list_head in an rcu safe * way, we must not access it directly */ @@ -191,9 +206,13 @@ static inline void list_splice_init_rcu(struct list_head *list, if (list_empty(list)) return; - /* "first" and "last" tracking list, so initialize it. */ + /* + * "first" and "last" tracking list, so initialize it. RCU readers + * have access to this list, so we must use INIT_LIST_HEAD_RCU() + * instead of INIT_LIST_HEAD(). + */ - INIT_LIST_HEAD(list); + INIT_LIST_HEAD_RCU(list); /* * At this point, the list body still points to the source list. |