[PATCH 2/4] timers: Add rb_init_node() to allow for stack allocated rb nodes

From: John Stultz
Date: Tue Apr 19 2011 - 19:58:56 EST


In cases where a timerqueue_node or some structure that utilizes
a timerqueue_node is allocated on the stack, gcc would give warnings
caused by the timerqueue_init()'s calling RB_CLEAR_NODE, which
self-references the nodes uninitialized data.

The solution is to create an rb_init_node() function that zeros
the rb_node structure out and then calls RB_CLEAR_NODE(), and
then call the new init function from timerqueue_init().

CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
include/linux/rbtree.h | 8 ++++++++
include/linux/timerqueue.h | 2 +-
2 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 7066acb..033b507 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -136,6 +136,14 @@ static inline void rb_set_color(struct rb_node *rb, int color)
#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))

+static inline void rb_init_node(struct rb_node *rb)
+{
+ rb->rb_parent_color = 0;
+ rb->rb_right = NULL;
+ rb->rb_left = NULL;
+ RB_CLEAR_NODE(rb);
+}
+
extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);

diff --git a/include/linux/timerqueue.h b/include/linux/timerqueue.h
index a520fd7..5088727 100644
--- a/include/linux/timerqueue.h
+++ b/include/linux/timerqueue.h
@@ -39,7 +39,7 @@ struct timerqueue_node *timerqueue_getnext(struct timerqueue_head *head)

static inline void timerqueue_init(struct timerqueue_node *node)
{
- RB_CLEAR_NODE(&node->node);
+ rb_init_node(&node->node);
}

static inline void timerqueue_init_head(struct timerqueue_head *head)
--
1.7.3.2.146.gca209

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