diff options
Diffstat (limited to 'lib/rbtree.c')
| -rw-r--r-- | lib/rbtree.c | 65 |
1 files changed, 50 insertions, 15 deletions
diff --git a/lib/rbtree.c b/lib/rbtree.c index 4ba2828a67c0..ba4a9d165f1b 100644 --- a/lib/rbtree.c +++ b/lib/rbtree.c @@ -95,22 +95,35 @@ __rb_rotate_set_parents(struct rb_node *old, struct rb_node *new, static __always_inline void __rb_insert(struct rb_node *node, struct rb_root *root, + bool newleft, struct rb_node **leftmost, void (*augment_rotate)(struct rb_node *old, struct rb_node *new)) { struct rb_node *parent = rb_red_parent(node), *gparent, *tmp; + if (newleft) + *leftmost = node; + while (true) { /* - * Loop invariant: node is red - * - * If there is a black parent, we are done. - * Otherwise, take some corrective action as we don't - * want a red root or two consecutive red nodes. + * Loop invariant: node is red. */ - if (!parent) { + if (unlikely(!parent)) { + /* + * The inserted node is root. Either this is the + * first node, or we recursed at Case 1 below and + * are no longer violating 4). + */ rb_set_parent_color(node, NULL, RB_BLACK); break; - } else if (rb_is_black(parent)) + } + + /* + * If there is a black parent, we are done. + * Otherwise, take some corrective action as, + * per 4), we don't want a red root or two + * consecutive red nodes. + */ + if(rb_is_black(parent)) break; gparent = rb_red_parent(parent); @@ -119,7 +132,7 @@ __rb_insert(struct rb_node *node, struct rb_root *root, if (parent != tmp) { /* parent == gparent->rb_left */ if (tmp && rb_is_red(tmp)) { /* - * Case 1 - color flips + * Case 1 - node's uncle is red (color flips). * * G g * / \ / \ @@ -142,7 +155,8 @@ __rb_insert(struct rb_node *node, struct rb_root *root, tmp = parent->rb_right; if (node == tmp) { /* - * Case 2 - left rotate at parent + * Case 2 - node's uncle is black and node is + * the parent's right child (left rotate at parent). * * G G * / \ / \ @@ -166,7 +180,8 @@ __rb_insert(struct rb_node *node, struct rb_root *root, } /* - * Case 3 - right rotate at gparent + * Case 3 - node's uncle is black and node is + * the parent's left child (right rotate at gparent). * * G P * / \ / \ @@ -434,19 +449,38 @@ static const struct rb_augment_callbacks dummy_callbacks = { void rb_insert_color(struct rb_node *node, struct rb_root *root) { - __rb_insert(node, root, dummy_rotate); + __rb_insert(node, root, false, NULL, dummy_rotate); } EXPORT_SYMBOL(rb_insert_color); void rb_erase(struct rb_node *node, struct rb_root *root) { struct rb_node *rebalance; - rebalance = __rb_erase_augmented(node, root, &dummy_callbacks); + rebalance = __rb_erase_augmented(node, root, + NULL, &dummy_callbacks); if (rebalance) ____rb_erase_color(rebalance, root, dummy_rotate); } EXPORT_SYMBOL(rb_erase); +void rb_insert_color_cached(struct rb_node *node, + struct rb_root_cached *root, bool leftmost) +{ + __rb_insert(node, &root->rb_root, leftmost, + &root->rb_leftmost, dummy_rotate); +} +EXPORT_SYMBOL(rb_insert_color_cached); + +void rb_erase_cached(struct rb_node *node, struct rb_root_cached *root) +{ + struct rb_node *rebalance; + rebalance = __rb_erase_augmented(node, &root->rb_root, + &root->rb_leftmost, &dummy_callbacks); + if (rebalance) + ____rb_erase_color(rebalance, &root->rb_root, dummy_rotate); +} +EXPORT_SYMBOL(rb_erase_cached); + /* * Augmented rbtree manipulation functions. * @@ -455,9 +489,10 @@ EXPORT_SYMBOL(rb_erase); */ void __rb_insert_augmented(struct rb_node *node, struct rb_root *root, + bool newleft, struct rb_node **leftmost, void (*augment_rotate)(struct rb_node *old, struct rb_node *new)) { - __rb_insert(node, root, augment_rotate); + __rb_insert(node, root, newleft, leftmost, augment_rotate); } EXPORT_SYMBOL(__rb_insert_augmented); @@ -502,7 +537,7 @@ struct rb_node *rb_next(const struct rb_node *node) * as we can. */ if (node->rb_right) { - node = node->rb_right; + node = node->rb_right; while (node->rb_left) node=node->rb_left; return (struct rb_node *)node; @@ -534,7 +569,7 @@ struct rb_node *rb_prev(const struct rb_node *node) * as we can. */ if (node->rb_left) { - node = node->rb_left; + node = node->rb_left; while (node->rb_right) node=node->rb_right; return (struct rb_node *)node; |