[PATCH v6 02/11] erofs-utils: lib: add list_splice_tail() helper

[Jingbo Xu <jefflexu@linux.alibaba.com>]

Add list_splice_tail() helper.

Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
---
 include/erofs/list.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/erofs/list.h b/include/erofs/list.h
index 3f5da1a..d7a9fee 100644
--- a/include/erofs/list.h
+++ b/include/erofs/list.h
@@ -70,6 +70,26 @@ static inline int list_empty(struct list_head *head)
 	return head->next == head;
 }
 
+static inline void __list_splice(struct list_head *list,
+		struct list_head *prev, struct list_head *next)
+{
+	struct list_head *first = list->next;
+	struct list_head *last = list->prev;
+
+	first->prev = prev;
+	prev->next = first;
+
+	last->next = next;
+	next->prev = last;
+}
+
+static inline void list_splice_tail(struct list_head *list,
+				    struct list_head *head)
+{
+	if (!list_empty(list))
+		__list_splice(list, head->prev, head);
+}
+
 #define list_entry(ptr, type, member) container_of(ptr, type, member)
 
 #define list_first_entry(ptr, type, member)                                    \
-- 
2.19.1.6.gb485710b