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Subject[PATCH 2/6] list: Introduce list_rotate_left()
Date
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>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
---
include/linux/list.h | 14 ++++++++++++++
1 files changed, 14 insertions(+), 0 deletions(-)
diff --git a/include/linux/list.h b/include/linux/list.h
index 969f6e9..5d9c655 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.
*/
--
1.6.2.3


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