1 files changed, 78 insertions, 9 deletions

diff --git a/include/linux/list.h b/include/linux/list.h
index 453916bc0412..db35ef02e745 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -214,22 +214,62 @@ static inline int list_is_singular(const struct list_head *head)
         return !list_empty(head) && (head->next == head->prev);
 }
 
+static inline void __list_cut_position(struct list_head *list,
+                struct list_head *head, struct list_head *entry)
+{
+        struct list_head *new_first = entry->next;
+        list->next = head->next;
+        list->next->prev = list;
+        list->prev = entry;
+        entry->next = list;
+        head->next = new_first;
+        new_first->prev = head;
+}
+
+/**
+ * list_cut_position - cut a list into two
+ * @list: a new list to add all removed entries
+ * @head: a list with entries
+ * @entry: an entry within head, could be the head itself
+ *      and if so we won't cut the list
+ *
+ * This helper moves the initial part of @head, up to and
+ * including @entry, from @head to @list. You should
+ * pass on @entry an element you know is on @head. @list
+ * should be an empty list or a list you do not care about
+ * losing its data.
+ *
+ */
+static inline void list_cut_position(struct list_head *list,
+                struct list_head *head, struct list_head *entry)
+{
+        if (list_empty(head))
+                return;
+        if (list_is_singular(head) &&
+                (head->next != entry && head != entry))
+                return;
+        if (entry == head)
+                INIT_LIST_HEAD(list);
+        else
+                __list_cut_position(list, head, entry);
+}
+
 static inline void __list_splice(const struct list_head *list,
-                                 struct list_head *head)
+                                 struct list_head *prev,
+                                 struct list_head *next)
 {
         struct list_head *first = list->next;
         struct list_head *last = list->prev;
-        struct list_head *at = head->next;
 
-        first->prev = head;
-        head->next = first;
+        first->prev = prev;
+        prev->next = first;
 
-        last->next = at;
-        at->prev = last;
+        last->next = next;
+        next->prev = last;
 }
 
 /**
- * list_splice - join two lists
+ * list_splice - join two lists, this is designed for stacks
  * @list: the new list to add.
  * @head: the place to add it in the first list.
  */
@@ -237,7 +277,19 @@ static inline void list_splice(const struct list_head *list,
                                 struct list_head *head)
 {
         if (!list_empty(list))
-                __list_splice(list, head);
+                __list_splice(list, head, head->next);
+}
+
+/**
+ * list_splice_tail - join two lists, each list being a queue
+ * @list: the new list to add.
+ * @head: the place to add it in the first list.
+ */
+static inline void list_splice_tail(struct list_head *list,
+                                struct list_head *head)
+{
+        if (!list_empty(list))
+                __list_splice(list, head->prev, head);
 }
 
 /**
@@ -251,7 +303,24 @@ static inline void list_splice_init(struct list_head *list,
                                     struct list_head *head)
 {
         if (!list_empty(list)) {
-                __list_splice(list, head);
+                __list_splice(list, head, head->next);
+                INIT_LIST_HEAD(list);
+        }
+}
+
+/**
+ * list_splice_tail_init - join two lists and reinitialise the emptied list
+ * @list: the new list to add.
+ * @head: the place to add it in the first list.
+ *
+ * Each of the lists is a queue.
+ * The list at @list is reinitialised
+ */
+static inline void list_splice_tail_init(struct list_head *list,
+                                         struct list_head *head)
+{
+        if (!list_empty(list)) {
+                __list_splice(list, head->prev, head);
                 INIT_LIST_HEAD(list);
         }
 }