diff options
| -rw-r--r-- | lib/radix-tree.c | 46 |
1 files changed, 36 insertions, 10 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 336852f23592..c0bd4a914803 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -253,7 +253,7 @@ int radix_tree_insert(struct radix_tree_root *root, shift = (height-1) * RADIX_TREE_MAP_SHIFT; offset = 0; /* uninitialised var warning */ - while (height > 0) { + do { if (slot == NULL) { /* Have to add a child node. */ if (!(slot = radix_tree_node_alloc(root))) @@ -271,18 +271,16 @@ int radix_tree_insert(struct radix_tree_root *root, slot = node->slots[offset]; shift -= RADIX_TREE_MAP_SHIFT; height--; - } + } while (height > 0); if (slot != NULL) return -EEXIST; - if (node) { - node->count++; - node->slots[offset] = item; - BUG_ON(tag_get(node, 0, offset)); - BUG_ON(tag_get(node, 1, offset)); - } else - root->rnode = item; + BUG_ON(!node); + node->count++; + node->slots[offset] = item; + BUG_ON(tag_get(node, 0, offset)); + BUG_ON(tag_get(node, 1, offset)); return 0; } @@ -680,6 +678,29 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, EXPORT_SYMBOL(radix_tree_gang_lookup_tag); /** + * radix_tree_shrink - shrink height of a radix tree to minimal + * @root radix tree root + */ +static inline void radix_tree_shrink(struct radix_tree_root *root) +{ + /* try to shrink tree height */ + while (root->height > 1 && + root->rnode->count == 1 && + root->rnode->slots[0]) { + struct radix_tree_node *to_free = root->rnode; + + root->rnode = to_free->slots[0]; + root->height--; + /* must only free zeroed nodes into the slab */ + tag_clear(to_free, 0, 0); + tag_clear(to_free, 1, 0); + to_free->slots[0] = NULL; + to_free->count = 0; + radix_tree_node_free(to_free); + } +} + +/** * radix_tree_delete - delete an item from a radix tree * @root: radix tree root * @index: index key @@ -755,8 +776,13 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) /* Now free the nodes we do not need anymore */ for (pathp = orig_pathp; pathp->node; pathp--) { pathp->node->slots[pathp->offset] = NULL; - if (--pathp->node->count) + pathp->node->count--; + + if (pathp->node->count) { + if (pathp->node == root->rnode) + radix_tree_shrink(root); goto out; + } /* Node with zero slots in use so free it */ radix_tree_node_free(pathp->node); |