[PATCH v1 1/2] erofs-utils: add list_replace from linux kernel for dirs sorted later

[Li Guifu]

A temp list head will be replaced to inode i_subdirs.

Signed-off-by: Li Guifu <bluce.lee at aliyun.com>
---
 include/erofs/list.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/erofs/list.h b/include/erofs/list.h
index 3572726..7238418 100644
--- a/include/erofs/list.h
+++ b/include/erofs/list.h
@@ -67,6 +67,22 @@ static inline int list_empty(struct list_head *head)
 	return head->next == head;
 }
 
+/**
+ * list_replace - replace old entry by new one
+ * @old : the element to be replaced
+ * @new : the new element to insert
+ *
+ * If @old was empty, it will be overwritten.
+ */
+static inline void list_replace(struct list_head *old,
+				struct list_head *new)
+{
+	new->next = old->next;
+	new->next->prev = new;
+	new->prev = old->prev;
+	new->prev->next = new;
+}
+
 #define list_entry(ptr, type, member) container_of(ptr, type, member)
 
 #define list_first_entry(ptr, type, member)                                    \
-- 
2.17.1