[RBTREE] Change rbtree off-tree marking in I/O schedulers.
They were abusing the rb_color field to mark nodes which weren't currently
on the tree. Fix that to use the same method as eventpoll did -- setting
the parent pointer to point back to itself. And use the appropriate
accessor macros for setting and reading the parent.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/block/as-iosched.c b/block/as-iosched.c
index e25a5d7..ed336ab 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -353,10 +353,9 @@
/*
* rb tree support functions
*/
-#define RB_NONE (2)
#define RB_EMPTY(root) ((root)->rb_node == NULL)
-#define ON_RB(node) ((node)->rb_color != RB_NONE)
-#define RB_CLEAR(node) ((node)->rb_color = RB_NONE)
+#define ON_RB(node) (rb_parent(node) != node)
+#define RB_CLEAR(node) (rb_set_parent(node, node))
#define rb_entry_arq(node) rb_entry((node), struct as_rq, rb_node)
#define ARQ_RB_ROOT(ad, arq) (&(ad)->sort_list[(arq)->is_sync])
#define rq_rb_key(rq) (rq)->sector