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authorFrederic Weisbecker <fweisbec@gmail.com>2010-01-09 20:53:14 +0100
committerFrederic Weisbecker <fweisbec@gmail.com>2010-01-16 12:29:32 +0100
commit5908cdc85eb30f8d07f2cb11d4a62334d7229048 (patch)
tree6d63ec247a47b957bea52578e77c8d6bda942eb0
parent889ff0150661512d79484219612b7e2e024b6c07 (diff)
list: Introduce list_rotate_left()
Bring a new list_rotate_left() helper that rotates a list to the left. This is useful for codes that need to round roubin elements which queue priority increases from tail to head. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
-rw-r--r--include/linux/list.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/list.h b/include/linux/list.h
index 969f6e92d08..5d9c6558e8a 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -206,6 +206,20 @@ static inline int list_empty_careful(const struct list_head *head)
}
/**
+ * list_rotate_left - rotate the list to the left
+ * @head: the head of the list
+ */
+static inline void list_rotate_left(struct list_head *head)
+{
+ struct list_head *first;
+
+ if (!list_empty(head)) {
+ first = head->next;
+ list_move_tail(first, head);
+ }
+}
+
+/**
* list_is_singular - tests whether a list has just one entry.
* @head: the list to test.
*/