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/core-api/rbtree.rst 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 23struct 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 30struct rb_root { 31 struct rb_node *rb_node; 32}; 33 34#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) 35 36#define RB_ROOT (struct rb_root) { NULL, } 37#define rb_entry(ptr, type, member) container_of(ptr, type, member) 38 39#define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL) 40 41/* 'empty' nodes are nodes that are known not to be inserted in an rbtree */ 42#define RB_EMPTY_NODE(node) \ 43 ((node)->__rb_parent_color == (unsigned long)(node)) 44#define RB_CLEAR_NODE(node) \ 45 ((node)->__rb_parent_color = (unsigned long)(node)) 46 47 48extern void rb_insert_color(struct rb_node *, struct rb_root *); 49extern void rb_erase(struct rb_node *, struct rb_root *); 50 51 52/* Find logical next and previous nodes in a tree */ 53extern struct rb_node *rb_next(const struct rb_node *); 54extern struct rb_node *rb_prev(const struct rb_node *); 55extern struct rb_node *rb_first(const struct rb_root *); 56extern struct rb_node *rb_last(const struct rb_root *); 57 58/* Postorder iteration - always visit the parent after its children */ 59extern struct rb_node *rb_first_postorder(const struct rb_root *); 60extern struct rb_node *rb_next_postorder(const struct rb_node *); 61 62/* Fast replacement of a single node without remove/rebalance/add/rebalance */ 63extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 64 struct rb_root *root); 65 66static inline void rb_link_node(struct rb_node *node, struct rb_node *parent, 67 struct rb_node **rb_link) 68{ 69 node->__rb_parent_color = (unsigned long)parent; 70 node->rb_left = node->rb_right = NULL; 71 72 *rb_link = node; 73} 74 75#define rb_entry_safe(ptr, type, member) \ 76 ({ typeof(ptr) ____ptr = (ptr); \ 77 ____ptr ? rb_entry(____ptr, type, member) : NULL; \ 78 }) 79 80/** 81 * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of 82 * given type allowing the backing memory of @pos to be invalidated 83 * 84 * @pos: the 'type *' to use as a loop cursor. 85 * @n: another 'type *' to use as temporary storage 86 * @root: 'rb_root *' of the rbtree. 87 * @field: the name of the rb_node field within 'type'. 88 * 89 * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as 90 * list_for_each_entry_safe() and allows the iteration to continue independent 91 * of changes to @pos by the body of the loop. 92 * 93 * Note, however, that it cannot handle other modifications that re-order the 94 * rbtree it is iterating over. This includes calling rb_erase() on @pos, as 95 * rb_erase() may rebalance the tree, causing us to miss some nodes. 96 */ 97#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \ 98 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \ 99 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \ 100 typeof(*pos), field); 1; }); \ 101 pos = n) 102 103static inline void rb_erase_init(struct rb_node *n, struct rb_root *root) 104{ 105 rb_erase(n, root); 106 RB_CLEAR_NODE(n); 107} 108 109/* 110 * Leftmost-cached rbtrees. 111 * 112 * We do not cache the rightmost node based on footprint 113 * size vs number of potential users that could benefit 114 * from O(1) rb_last(). Just not worth it, users that want 115 * this feature can always implement the logic explicitly. 116 * Furthermore, users that want to cache both pointers may 117 * find it a bit asymmetric, but that's ok. 118 */ 119struct rb_root_cached { 120 struct rb_root rb_root; 121 struct rb_node *rb_leftmost; 122}; 123 124#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL } 125 126/* Same as rb_first(), but O(1) */ 127#define rb_first_cached(root) (root)->rb_leftmost 128 129static inline void rb_insert_color_cached(struct rb_node *node, 130 struct rb_root_cached *root, 131 bool leftmost) 132{ 133 if (leftmost) 134 root->rb_leftmost = node; 135 rb_insert_color(node, &root->rb_root); 136} 137 138static inline void rb_erase_cached(struct rb_node *node, 139 struct rb_root_cached *root) 140{ 141 if (root->rb_leftmost == node) 142 root->rb_leftmost = rb_next(node); 143 rb_erase(node, &root->rb_root); 144} 145 146static inline void rb_replace_node_cached(struct rb_node *victim, 147 struct rb_node *new, 148 struct rb_root_cached *root) 149{ 150 if (root->rb_leftmost == victim) 151 root->rb_leftmost = new; 152 rb_replace_node(victim, new, &root->rb_root); 153} 154 155/* 156 * The below helper functions use 2 operators with 3 different 157 * calling conventions. The operators are related like: 158 * 159 * comp(a->key,b) < 0 := less(a,b) 160 * comp(a->key,b) > 0 := less(b,a) 161 * comp(a->key,b) == 0 := !less(a,b) && !less(b,a) 162 * 163 * If these operators define a partial order on the elements we make no 164 * guarantee on which of the elements matching the key is found. See 165 * rb_find(). 166 * 167 * The reason for this is to allow the find() interface without requiring an 168 * on-stack dummy object, which might not be feasible due to object size. 169 */ 170 171/** 172 * rb_add_cached() - insert @node into the leftmost cached tree @tree 173 * @node: node to insert 174 * @tree: leftmost cached tree to insert @node into 175 * @less: operator defining the (partial) node order 176 */ 177static __always_inline void 178rb_add_cached(struct rb_node *node, struct rb_root_cached *tree, 179 bool (*less)(struct rb_node *, const struct rb_node *)) 180{ 181 struct rb_node **link = &tree->rb_root.rb_node; 182 struct rb_node *parent = NULL; 183 bool leftmost = true; 184 185 while (*link) { 186 parent = *link; 187 if (less(node, parent)) { 188 link = &parent->rb_left; 189 } else { 190 link = &parent->rb_right; 191 leftmost = false; 192 } 193 } 194 195 rb_link_node(node, parent, link); 196 rb_insert_color_cached(node, tree, leftmost); 197} 198 199/** 200 * rb_add() - insert @node into @tree 201 * @node: node to insert 202 * @tree: tree to insert @node into 203 * @less: operator defining the (partial) node order 204 */ 205static __always_inline void 206rb_add(struct rb_node *node, struct rb_root *tree, 207 bool (*less)(struct rb_node *, const struct rb_node *)) 208{ 209 struct rb_node **link = &tree->rb_node; 210 struct rb_node *parent = NULL; 211 212 while (*link) { 213 parent = *link; 214 if (less(node, parent)) 215 link = &parent->rb_left; 216 else 217 link = &parent->rb_right; 218 } 219 220 rb_link_node(node, parent, link); 221 rb_insert_color(node, tree); 222} 223 224/** 225 * rb_find_add() - find equivalent @node in @tree, or add @node 226 * @node: node to look-for / insert 227 * @tree: tree to search / modify 228 * @cmp: operator defining the node order 229 * 230 * Returns the rb_node matching @node, or NULL when no match is found and @node 231 * is inserted. 232 */ 233static __always_inline struct rb_node * 234rb_find_add(struct rb_node *node, struct rb_root *tree, 235 int (*cmp)(struct rb_node *, const struct rb_node *)) 236{ 237 struct rb_node **link = &tree->rb_node; 238 struct rb_node *parent = NULL; 239 int c; 240 241 while (*link) { 242 parent = *link; 243 c = cmp(node, parent); 244 245 if (c < 0) 246 link = &parent->rb_left; 247 else if (c > 0) 248 link = &parent->rb_right; 249 else 250 return parent; 251 } 252 253 rb_link_node(node, parent, link); 254 rb_insert_color(node, tree); 255 return NULL; 256} 257 258/** 259 * rb_find() - find @key in tree @tree 260 * @key: key to match 261 * @tree: tree to search 262 * @cmp: operator defining the node order 263 * 264 * Returns the rb_node matching @key or NULL. 265 */ 266static __always_inline struct rb_node * 267rb_find(const void *key, const struct rb_root *tree, 268 int (*cmp)(const void *key, const struct rb_node *)) 269{ 270 struct rb_node *node = tree->rb_node; 271 272 while (node) { 273 int c = cmp(key, node); 274 275 if (c < 0) 276 node = node->rb_left; 277 else if (c > 0) 278 node = node->rb_right; 279 else 280 return node; 281 } 282 283 return NULL; 284} 285 286/** 287 * rb_find_first() - find the first @key in @tree 288 * @key: key to match 289 * @tree: tree to search 290 * @cmp: operator defining node order 291 * 292 * Returns the leftmost node matching @key, or NULL. 293 */ 294static __always_inline struct rb_node * 295rb_find_first(const void *key, const struct rb_root *tree, 296 int (*cmp)(const void *key, const struct rb_node *)) 297{ 298 struct rb_node *node = tree->rb_node; 299 struct rb_node *match = NULL; 300 301 while (node) { 302 int c = cmp(key, node); 303 304 if (c <= 0) { 305 if (!c) 306 match = node; 307 node = node->rb_left; 308 } else if (c > 0) { 309 node = node->rb_right; 310 } 311 } 312 313 return match; 314} 315 316/** 317 * rb_next_match() - find the next @key in @tree 318 * @key: key to match 319 * @tree: tree to search 320 * @cmp: operator defining node order 321 * 322 * Returns the next node matching @key, or NULL. 323 */ 324static __always_inline struct rb_node * 325rb_next_match(const void *key, struct rb_node *node, 326 int (*cmp)(const void *key, const struct rb_node *)) 327{ 328 node = rb_next(node); 329 if (node && cmp(key, node)) 330 node = NULL; 331 return node; 332} 333 334/** 335 * rb_for_each() - iterates a subtree matching @key 336 * @node: iterator 337 * @key: key to match 338 * @tree: tree to search 339 * @cmp: operator defining node order 340 */ 341#define rb_for_each(node, key, tree, cmp) \ 342 for ((node) = rb_find_first((key), (tree), (cmp)); \ 343 (node); (node) = rb_next_match((key), (node), (cmp))) 344 345#endif /* __TOOLS_LINUX_PERF_RBTREE_H */ 346