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>

1 files changed, 46 insertions, 19 deletions

diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index 8acaddd0fb21..7e1515bd4770 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;
 }