rbtree: remove prior augmented rbtree implementation

convert arch/x86/mm/pat_rbtree.c to the proposed augmented rbtree api
and remove the old augmented rbtree implementation.

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: 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>

3 files changed, 46 insertions, 98 deletions

diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index 8acaddd0fb2..7e1515bd477 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -54,29 +54,57 @@ static u64 get_subtree_max_end(struct rb_node *node)
         return ret;
 }
 
-/* Update 'subtree_max_end' for a node, based on node and its children */
-static void memtype_rb_augment_cb(struct rb_node *node, void *__unused)
+static u64 compute_subtree_max_end(struct memtype *data)
 {
-        struct memtype *data;
-        u64 max_end, child_max_end;
-
-        if (!node)
-                return;
-
-        data = container_of(node, struct memtype, rb);
-        max_end = data->end;
+        u64 max_end = data->end, child_max_end;
 
-        child_max_end = get_subtree_max_end(node->rb_right);
+        child_max_end = get_subtree_max_end(data->rb.rb_right);
         if (child_max_end > max_end)
                 max_end = child_max_end;
 
-        child_max_end = get_subtree_max_end(node->rb_left);
+        child_max_end = get_subtree_max_end(data->rb.rb_left);
         if (child_max_end > max_end)
                 max_end = child_max_end;
 
-        data->subtree_max_end = max_end;
+        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
+};
+
 /* Find the first (lowest start addr) overlapping range from rb tree */
 static struct memtype *memtype_rb_lowest_match(struct rb_root *root,
                                 u64 start, u64 end)
@@ -179,15 +207,17 @@ static void memtype_rb_insert(struct rb_root *root, struct memtype *newdata)
                 struct memtype *data = container_of(*node, struct memtype, rb);
 
                 parent = *node;
+                if (data->subtree_max_end < newdata->end)
+                        data->subtree_max_end = newdata->end;
                 if (newdata->start <= data->start)
                         node = &((*node)->rb_left);
                 else if (newdata->start > data->start)
                         node = &((*node)->rb_right);
         }
 
+        newdata->subtree_max_end = newdata->end;
         rb_link_node(&newdata->rb, parent, node);
-        rb_insert_color(&newdata->rb, root);
-        rb_augment_insert(&newdata->rb, memtype_rb_augment_cb, NULL);
+        rb_insert_augmented(&newdata->rb, root, &memtype_rb_augment_cb);
 }
 
 int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
@@ -209,16 +239,13 @@ int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
 
 struct memtype *rbt_memtype_erase(u64 start, u64 end)
 {
-        struct rb_node *deepest;
         struct memtype *data;
 
         data = memtype_rb_exact_match(&memtype_rbroot, start, end);
         if (!data)
                 goto out;
 
-        deepest = rb_augment_erase_begin(&data->rb);
-        rb_erase(&data->rb, &memtype_rbroot);
-        rb_augment_erase_end(deepest, memtype_rb_augment_cb, NULL);
+        rb_erase_augmented(&data->rb, &memtype_rbroot, &memtype_rb_augment_cb);
 out:
         return data;
 }
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index c902eb9d650..4ace31b3338 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -80,14 +80,6 @@ rb_insert_augmented(struct rb_node *node, struct rb_root *root,
 }
 
 
-typedef void (*rb_augment_f)(struct rb_node *node, void *data);
-
-extern void rb_augment_insert(struct rb_node *node,
-                              rb_augment_f func, void *data);
-extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
-extern void rb_augment_erase_end(struct rb_node *node,
-                                 rb_augment_f func, void *data);
-
 /* Find logical next and previous nodes in a tree */
 extern struct rb_node *rb_next(const struct rb_node *);
 extern struct rb_node *rb_prev(const struct rb_node *);
diff --git a/lib/rbtree.c b/lib/rbtree.c
index a37ee7954b8..c0088ca345f 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -538,77 +538,6 @@ void rb_erase_augmented(struct rb_node *node, struct rb_root *root,
 }
 EXPORT_SYMBOL(rb_erase_augmented);
 
-static void rb_augment_path(struct rb_node *node, rb_augment_f func, void *data)
-{
-        struct rb_node *parent;
-
-up:
-        func(node, data);
-        parent = rb_parent(node);
-        if (!parent)
-                return;
-
-        if (node == parent->rb_left && parent->rb_right)
-                func(parent->rb_right, data);
-        else if (parent->rb_left)
-                func(parent->rb_left, data);
-
-        node = parent;
-        goto up;
-}
-
-/*
- * after inserting @node into the tree, update the tree to account for
- * both the new entry and any damage done by rebalance
- */
-void rb_augment_insert(struct rb_node *node, rb_augment_f func, void *data)
-{
-        if (node->rb_left)
-                node = node->rb_left;
-        else if (node->rb_right)
-                node = node->rb_right;
-
-        rb_augment_path(node, func, data);
-}
-EXPORT_SYMBOL(rb_augment_insert);
-
-/*
- * before removing the node, find the deepest node on the rebalance path
- * that will still be there after @node gets removed
- */
-struct rb_node *rb_augment_erase_begin(struct rb_node *node)
-{
-        struct rb_node *deepest;
-
-        if (!node->rb_right && !node->rb_left)
-                deepest = rb_parent(node);
-        else if (!node->rb_right)
-                deepest = node->rb_left;
-        else if (!node->rb_left)
-                deepest = node->rb_right;
-        else {
-                deepest = rb_next(node);
-                if (deepest->rb_right)
-                        deepest = deepest->rb_right;
-                else if (rb_parent(deepest) != node)
-                        deepest = rb_parent(deepest);
-        }
-
-        return deepest;
-}
-EXPORT_SYMBOL(rb_augment_erase_begin);
-
-/*
- * after removal, update the tree to account for the removed entry
- * and any rebalance damage.
- */
-void rb_augment_erase_end(struct rb_node *node, rb_augment_f func, void *data)
-{
-        if (node)
-                rb_augment_path(node, func, data);
-}
-EXPORT_SYMBOL(rb_augment_erase_end);
-
 /*
  * This function returns the first node (in sort order) of the tree.
  */