rbtree: add RB_DECLARE_CALLBACKS() macro

As proposed by Peter Zijlstra, this makes it easier to define the augmented
rbtree callbacks.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index 7e1515b..4d11695 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -69,41 +69,8 @@
 	return max_end;
 }
 
-/* Update 'subtree_max_end' for node and its parents */
-static void memtype_rb_propagate_cb(struct rb_node *node, struct rb_node *stop)
-{
-	while (node != stop) {
-		struct memtype *data = container_of(node, struct memtype, rb);
-		u64 subtree_max_end = compute_subtree_max_end(data);
-		if (data->subtree_max_end == subtree_max_end)
-			break;
-		data->subtree_max_end = subtree_max_end;
-		node = rb_parent(&data->rb);
-	}
-}
-
-static void memtype_rb_copy_cb(struct rb_node *old, struct rb_node *new)
-{
-	struct memtype *old_data = container_of(old, struct memtype, rb);
-	struct memtype *new_data = container_of(new, struct memtype, rb);
-
-	new_data->subtree_max_end = old_data->subtree_max_end;
-}
-
-/* Update 'subtree_max_end' after tree rotation. old and new are the
- * former and current subtree roots */
-static void memtype_rb_rotate_cb(struct rb_node *old, struct rb_node *new)
-{
-	struct memtype *old_data = container_of(old, struct memtype, rb);
-	struct memtype *new_data = container_of(new, struct memtype, rb);
-
-	new_data->subtree_max_end = old_data->subtree_max_end;
-	old_data->subtree_max_end = compute_subtree_max_end(old_data);
-}
-
-static const struct rb_augment_callbacks memtype_rb_augment_cb = {
-	memtype_rb_propagate_cb, memtype_rb_copy_cb, memtype_rb_rotate_cb
-};
+RB_DECLARE_CALLBACKS(static, memtype_rb_augment_cb, struct memtype, rb,
+		     u64, subtree_max_end, compute_subtree_max_end)
 
 /* Find the first (lowest start addr) overlapping range from rb tree */
 static struct memtype *memtype_rb_lowest_match(struct rb_root *root,