diff options
Diffstat (limited to 'include/linux/llist.h')
| -rw-r--r-- | include/linux/llist.h | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/include/linux/llist.h b/include/linux/llist.h index 2c982ff7475a..8846b7709669 100644 --- a/include/linux/llist.h +++ b/include/linux/llist.h @@ -26,8 +26,8 @@ * * | add | del_first | del_all * add | - | - | - - * del_first | | L | L - * del_all | | | - + * del_first | - | L | L + * del_all | - | - | - * * Where, a particular row's operation can happen concurrently with a column's * operation, with "-" being no lock needed, while "L" being lock is needed. @@ -83,7 +83,7 @@ static inline void init_llist_head(struct llist_head *list) */ static inline void init_llist_node(struct llist_node *node) { - node->next = node; + WRITE_ONCE(node->next, node); } /** @@ -97,7 +97,7 @@ static inline void init_llist_node(struct llist_node *node) */ static inline bool llist_on_list(const struct llist_node *node) { - return node->next != node; + return READ_ONCE(node->next) != node; } /** @@ -220,12 +220,29 @@ static inline bool llist_empty(const struct llist_head *head) static inline struct llist_node *llist_next(struct llist_node *node) { - return node->next; + return READ_ONCE(node->next); } -extern bool llist_add_batch(struct llist_node *new_first, - struct llist_node *new_last, - struct llist_head *head); +/** + * llist_add_batch - add several linked entries in batch + * @new_first: first entry in batch to be added + * @new_last: last entry in batch to be added + * @head: the head for your lock-less list + * + * Return whether list is empty before adding. + */ +static inline bool llist_add_batch(struct llist_node *new_first, + struct llist_node *new_last, + struct llist_head *head) +{ + struct llist_node *first = READ_ONCE(head->first); + + do { + new_last->next = first; + } while (!try_cmpxchg(&head->first, &first, new_first)); + + return !first; +} static inline bool __llist_add_batch(struct llist_node *new_first, struct llist_node *new_last, |