[PATCH] rbtree: Examine rb_add* helpers in rbtree_test

[s921975628@gmail.com]

From: RinHizakura <s921975628@gmail.com>

We had introduced rb_add() and rb_add_cached() helper for the
partial-order based rbtree, which may be the most commonly way
to use rbtree. We also have rb_add_augmented_cached() for EEVDF now.
Since these helpers are actually the same as what rbtree_test examines
for, we can reuse these helpers to test them under rbtree_test directly.

This also introduces some correctness test and benchmarking for these
generic interface, which means the correctness and performance can be
minimally guarantee under the tests. User can choose to use these
great rb_add* helpers without extra effort to implement their own
one considering the test results.

Signed-off-by: Yiwei Lin <s921975628@gmail.com>
---
 include/linux/rbtree_augmented.h | 21 ++++++++
 lib/rbtree_test.c                | 82 +++++---------------------------
 2 files changed, 32 insertions(+), 71 deletions(-)

diff --git a/include/linux/rbtree_augmented.h b/include/linux/rbtree_augmented.h
index 6dbc5a1bf..e4d2d74ba 100644
--- a/include/linux/rbtree_augmented.h
+++ b/include/linux/rbtree_augmented.h
@@ -86,6 +86,27 @@ rb_add_augmented_cached(struct rb_node *node, struct rb_root_cached *tree,
 	return leftmost ? node : NULL;
 }
 
+static __always_inline void
+rb_add_augmented(struct rb_node *node, struct rb_root *tree,
+			bool (*less)(struct rb_node *, const struct rb_node *),
+			const struct rb_augment_callbacks *augment)
+{
+	struct rb_node **link = &tree->rb_node;
+	struct rb_node *parent = NULL;
+
+	while (*link) {
+		parent = *link;
+		if (less(node, parent))
+			link = &parent->rb_left;
+		else
+			link = &parent->rb_right;
+	}
+
+	rb_link_node(node, parent, link);
+	augment->propagate(parent, NULL);
+	rb_insert_augmented(node, tree, augment);
+}
+
 /*
  * Template for declaring augmented rbtree callbacks (generic case)
  *
diff --git a/lib/rbtree_test.c b/lib/rbtree_test.c
index 41ae3c757..5768512f3 100644
--- a/lib/rbtree_test.c
+++ b/lib/rbtree_test.c
@@ -29,41 +29,19 @@ static struct test_node *nodes = NULL;
 
 static struct rnd_state rnd;
 
-static void insert(struct test_node *node, struct rb_root_cached *root)
+static inline bool less(struct rb_node *a, const struct rb_node *b)
 {
-	struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
-	u32 key = node->key;
-
-	while (*new) {
-		parent = *new;
-		if (key < rb_entry(parent, struct test_node, rb)->key)
-			new = &parent->rb_left;
-		else
-			new = &parent->rb_right;
-	}
+	return rb_entry(a, struct test_node, rb)->key < rb_entry(b, struct test_node, rb)->key;
+}
 
-	rb_link_node(&node->rb, parent, new);
-	rb_insert_color(&node->rb, &root->rb_root);
+static void insert(struct test_node *node, struct rb_root_cached *root)
+{
+	rb_add(&node->rb, &root->rb_root, less);
 }
 
 static void insert_cached(struct test_node *node, struct rb_root_cached *root)
 {
-	struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
-	u32 key = node->key;
-	bool leftmost = true;
-
-	while (*new) {
-		parent = *new;
-		if (key < rb_entry(parent, struct test_node, rb)->key)
-			new = &parent->rb_left;
-		else {
-			new = &parent->rb_right;
-			leftmost = false;
-		}
-	}
-
-	rb_link_node(&node->rb, parent, new);
-	rb_insert_color_cached(&node->rb, root, leftmost);
+	rb_add_cached(&node->rb, root, less);
 }
 
 static inline void erase(struct test_node *node, struct rb_root_cached *root)
@@ -85,53 +63,15 @@ RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
 static void insert_augmented(struct test_node *node,
 			     struct rb_root_cached *root)
 {
-	struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
-	u32 key = node->key;
-	u32 val = node->val;
-	struct test_node *parent;
-
-	while (*new) {
-		rb_parent = *new;
-		parent = rb_entry(rb_parent, struct test_node, rb);
-		if (parent->augmented < val)
-			parent->augmented = val;
-		if (key < parent->key)
-			new = &parent->rb.rb_left;
-		else
-			new = &parent->rb.rb_right;
-	}
-
-	node->augmented = val;
-	rb_link_node(&node->rb, rb_parent, new);
-	rb_insert_augmented(&node->rb, &root->rb_root, &augment_callbacks);
+	node->augmented = node->val;
+	rb_add_augmented(&node->rb, &root->rb_root, less, &augment_callbacks);
 }
 
 static void insert_augmented_cached(struct test_node *node,
 				    struct rb_root_cached *root)
 {
-	struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
-	u32 key = node->key;
-	u32 val = node->val;
-	struct test_node *parent;
-	bool leftmost = true;
-
-	while (*new) {
-		rb_parent = *new;
-		parent = rb_entry(rb_parent, struct test_node, rb);
-		if (parent->augmented < val)
-			parent->augmented = val;
-		if (key < parent->key)
-			new = &parent->rb.rb_left;
-		else {
-			new = &parent->rb.rb_right;
-			leftmost = false;
-		}
-	}
-
-	node->augmented = val;
-	rb_link_node(&node->rb, rb_parent, new);
-	rb_insert_augmented_cached(&node->rb, root,
-				   leftmost, &augment_callbacks);
+	node->augmented = node->val;
+	rb_add_augmented_cached(&node->rb, root, less, &augment_callbacks);
 }
 
 
-- 
2.34.1