Add hlist_bl_add_before/behind helpers to add an element before/after an existing element in a bl_list.
Signed-off-by: Nikos Tsironis <[email protected]> Signed-off-by: Ilias Tsitsimpis <[email protected]> --- include/linux/list_bl.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index 3fc2cc57ba1b..2fd918e5fd48 100644 --- a/include/linux/list_bl.h +++ b/include/linux/list_bl.h @@ -86,6 +86,33 @@ static inline void hlist_bl_add_head(struct hlist_bl_node *n, hlist_bl_set_first(h, n); } +static inline void hlist_bl_add_before(struct hlist_bl_node *n, + struct hlist_bl_node *next) +{ + struct hlist_bl_node **pprev = next->pprev; + + n->pprev = pprev; + n->next = next; + next->pprev = &n->next; + + /* pprev may be `first`, so be careful not to lose the lock bit */ + WRITE_ONCE(*pprev, + (struct hlist_bl_node *) + ((unsigned long)n | + ((unsigned long)*pprev & LIST_BL_LOCKMASK))); +} + +static inline void hlist_bl_add_behind(struct hlist_bl_node *n, + struct hlist_bl_node *prev) +{ + n->next = prev->next; + n->pprev = &prev->next; + WRITE_ONCE(prev->next, n); + + if (n->next) + n->next->pprev = &n->next; +} + static inline void __hlist_bl_del(struct hlist_bl_node *n) { struct hlist_bl_node *next = n->next; -- 2.11.0 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
