1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 Red Black Trees 4 (C) 1999 Andrea Arcangeli <andrea@suse.de> 5 6 7 linux/include/linux/rbtree.h 8 9 To use rbtrees you'll have to implement your own insert and search cores. 10 This will avoid us to use callbacks and to drop drammatically performances. 11 I know it's not the cleaner way, but in C (not in C++) to get 12 performances and genericity... 13 14 See Documentation/rbtree.txt for documentation and samples. 15 */ 16 17 #ifndef __TOOLS_LINUX_PERF_RBTREE_H 18 #define __TOOLS_LINUX_PERF_RBTREE_H 19 20 #include <linux/kernel.h> 21 #include <linux/stddef.h> 22 23 struct rb_node { 24 unsigned long __rb_parent_color; 25 struct rb_node *rb_right; 26 struct rb_node *rb_left; 27 } __attribute__((aligned(sizeof(long)))); 28 /* The alignment might seem pointless, but allegedly CRIS needs it */ 29 30 struct rb_root { 31 struct rb_node *rb_node; 32 }; 33 34 /* 35 * Leftmost-cached rbtrees. 36 * 37 * We do not cache the rightmost node based on footprint 38 * size vs number of potential users that could benefit 39 * from O(1) rb_last(). Just not worth it, users that want 40 * this feature can always implement the logic explicitly. 41 * Furthermore, users that want to cache both pointers may 42 * find it a bit asymmetric, but that's ok. 43 */ 44 struct rb_root_cached { 45 struct rb_root rb_root; 46 struct rb_node *rb_leftmost; 47 }; 48 49 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) 50 51 #define RB_ROOT (struct rb_root) { NULL, } 52 #define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL } 53 #define rb_entry(ptr, type, member) container_of(ptr, type, member) 54 55 #define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL) 56 57 /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */ 58 #define RB_EMPTY_NODE(node) \ 59 ((node)->__rb_parent_color == (unsigned long)(node)) 60 #define RB_CLEAR_NODE(node) \ 61 ((node)->__rb_parent_color = (unsigned long)(node)) 62 63 64 extern void rb_insert_color(struct rb_node *, struct rb_root *); 65 extern void rb_erase(struct rb_node *, struct rb_root *); 66 67 68 /* Find logical next and previous nodes in a tree */ 69 extern struct rb_node *rb_next(const struct rb_node *); 70 extern struct rb_node *rb_prev(const struct rb_node *); 71 extern struct rb_node *rb_first(const struct rb_root *); 72 extern struct rb_node *rb_last(const struct rb_root *); 73 74 extern void rb_insert_color_cached(struct rb_node *, 75 struct rb_root_cached *, bool); 76 extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *); 77 /* Same as rb_first(), but O(1) */ 78 #define rb_first_cached(root) (root)->rb_leftmost 79 80 /* Postorder iteration - always visit the parent after its children */ 81 extern struct rb_node *rb_first_postorder(const struct rb_root *); 82 extern struct rb_node *rb_next_postorder(const struct rb_node *); 83 84 /* Fast replacement of a single node without remove/rebalance/add/rebalance */ 85 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 86 struct rb_root *root); 87 extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new, 88 struct rb_root_cached *root); 89 90 static inline void rb_link_node(struct rb_node *node, struct rb_node *parent, 91 struct rb_node **rb_link) 92 { 93 node->__rb_parent_color = (unsigned long)parent; 94 node->rb_left = node->rb_right = NULL; 95 96 *rb_link = node; 97 } 98 99 #define rb_entry_safe(ptr, type, member) \ 100 ({ typeof(ptr) ____ptr = (ptr); \ 101 ____ptr ? rb_entry(____ptr, type, member) : NULL; \ 102 }) 103 104 /** 105 * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of 106 * given type allowing the backing memory of @pos to be invalidated 107 * 108 * @pos: the 'type *' to use as a loop cursor. 109 * @n: another 'type *' to use as temporary storage 110 * @root: 'rb_root *' of the rbtree. 111 * @field: the name of the rb_node field within 'type'. 112 * 113 * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as 114 * list_for_each_entry_safe() and allows the iteration to continue independent 115 * of changes to @pos by the body of the loop. 116 * 117 * Note, however, that it cannot handle other modifications that re-order the 118 * rbtree it is iterating over. This includes calling rb_erase() on @pos, as 119 * rb_erase() may rebalance the tree, causing us to miss some nodes. 120 */ 121 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \ 122 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \ 123 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \ 124 typeof(*pos), field); 1; }); \ 125 pos = n) 126 127 static inline void rb_erase_init(struct rb_node *n, struct rb_root *root) 128 { 129 rb_erase(n, root); 130 RB_CLEAR_NODE(n); 131 } 132 #endif /* __TOOLS_LINUX_PERF_RBTREE_H */ 133