1*83d290c5STom Rini // SPDX-License-Identifier: GPL-2.0+
278acc472SPeter Tyser /*
378acc472SPeter Tyser Red Black Trees
478acc472SPeter Tyser (C) 1999 Andrea Arcangeli <andrea@suse.de>
578acc472SPeter Tyser (C) 2002 David Woodhouse <dwmw2@infradead.org>
69dd228b5SHeiko Schocher (C) 2012 Michel Lespinasse <walken@google.com>
778acc472SPeter Tyser
878acc472SPeter Tyser linux/lib/rbtree.c
978acc472SPeter Tyser */
1078acc472SPeter Tyser
119dd228b5SHeiko Schocher #include <linux/rbtree_augmented.h>
129dd228b5SHeiko Schocher #ifndef __UBOOT__
139dd228b5SHeiko Schocher #include <linux/export.h>
149dd228b5SHeiko Schocher #else
1578acc472SPeter Tyser #include <ubi_uboot.h>
169dd228b5SHeiko Schocher #endif
179dd228b5SHeiko Schocher /*
189dd228b5SHeiko Schocher * red-black trees properties: http://en.wikipedia.org/wiki/Rbtree
199dd228b5SHeiko Schocher *
209dd228b5SHeiko Schocher * 1) A node is either red or black
219dd228b5SHeiko Schocher * 2) The root is black
229dd228b5SHeiko Schocher * 3) All leaves (NULL) are black
239dd228b5SHeiko Schocher * 4) Both children of every red node are black
249dd228b5SHeiko Schocher * 5) Every simple path from root to leaves contains the same number
259dd228b5SHeiko Schocher * of black nodes.
269dd228b5SHeiko Schocher *
279dd228b5SHeiko Schocher * 4 and 5 give the O(log n) guarantee, since 4 implies you cannot have two
289dd228b5SHeiko Schocher * consecutive red nodes in a path and every red node is therefore followed by
299dd228b5SHeiko Schocher * a black. So if B is the number of black nodes on every simple path (as per
309dd228b5SHeiko Schocher * 5), then the longest possible path due to 4 is 2B.
319dd228b5SHeiko Schocher *
329dd228b5SHeiko Schocher * We shall indicate color with case, where black nodes are uppercase and red
339dd228b5SHeiko Schocher * nodes will be lowercase. Unknown color nodes shall be drawn as red within
349dd228b5SHeiko Schocher * parentheses and have some accompanying text comment.
359dd228b5SHeiko Schocher */
3678acc472SPeter Tyser
rb_set_black(struct rb_node * rb)379dd228b5SHeiko Schocher static inline void rb_set_black(struct rb_node *rb)
3878acc472SPeter Tyser {
399dd228b5SHeiko Schocher rb->__rb_parent_color |= RB_BLACK;
409dd228b5SHeiko Schocher }
4178acc472SPeter Tyser
rb_red_parent(struct rb_node * red)429dd228b5SHeiko Schocher static inline struct rb_node *rb_red_parent(struct rb_node *red)
439dd228b5SHeiko Schocher {
449dd228b5SHeiko Schocher return (struct rb_node *)red->__rb_parent_color;
459dd228b5SHeiko Schocher }
4678acc472SPeter Tyser
479dd228b5SHeiko Schocher /*
489dd228b5SHeiko Schocher * Helper function for rotations:
499dd228b5SHeiko Schocher * - old's parent and color get assigned to new
509dd228b5SHeiko Schocher * - old gets assigned new as a parent and 'color' as a color.
519dd228b5SHeiko Schocher */
529dd228b5SHeiko Schocher static inline void
__rb_rotate_set_parents(struct rb_node * old,struct rb_node * new,struct rb_root * root,int color)539dd228b5SHeiko Schocher __rb_rotate_set_parents(struct rb_node *old, struct rb_node *new,
549dd228b5SHeiko Schocher struct rb_root *root, int color)
559dd228b5SHeiko Schocher {
569dd228b5SHeiko Schocher struct rb_node *parent = rb_parent(old);
579dd228b5SHeiko Schocher new->__rb_parent_color = old->__rb_parent_color;
589dd228b5SHeiko Schocher rb_set_parent_color(old, new, color);
599dd228b5SHeiko Schocher __rb_change_child(old, new, parent, root);
609dd228b5SHeiko Schocher }
6178acc472SPeter Tyser
629dd228b5SHeiko Schocher static __always_inline void
__rb_insert(struct rb_node * node,struct rb_root * root,void (* augment_rotate)(struct rb_node * old,struct rb_node * new))639dd228b5SHeiko Schocher __rb_insert(struct rb_node *node, struct rb_root *root,
649dd228b5SHeiko Schocher void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
659dd228b5SHeiko Schocher {
669dd228b5SHeiko Schocher struct rb_node *parent = rb_red_parent(node), *gparent, *tmp;
679dd228b5SHeiko Schocher
689dd228b5SHeiko Schocher while (true) {
699dd228b5SHeiko Schocher /*
709dd228b5SHeiko Schocher * Loop invariant: node is red
719dd228b5SHeiko Schocher *
729dd228b5SHeiko Schocher * If there is a black parent, we are done.
739dd228b5SHeiko Schocher * Otherwise, take some corrective action as we don't
749dd228b5SHeiko Schocher * want a red root or two consecutive red nodes.
759dd228b5SHeiko Schocher */
769dd228b5SHeiko Schocher if (!parent) {
779dd228b5SHeiko Schocher rb_set_parent_color(node, NULL, RB_BLACK);
789dd228b5SHeiko Schocher break;
799dd228b5SHeiko Schocher } else if (rb_is_black(parent))
809dd228b5SHeiko Schocher break;
819dd228b5SHeiko Schocher
829dd228b5SHeiko Schocher gparent = rb_red_parent(parent);
839dd228b5SHeiko Schocher
849dd228b5SHeiko Schocher tmp = gparent->rb_right;
859dd228b5SHeiko Schocher if (parent != tmp) { /* parent == gparent->rb_left */
869dd228b5SHeiko Schocher if (tmp && rb_is_red(tmp)) {
879dd228b5SHeiko Schocher /*
889dd228b5SHeiko Schocher * Case 1 - color flips
899dd228b5SHeiko Schocher *
909dd228b5SHeiko Schocher * G g
919dd228b5SHeiko Schocher * / \ / \
929dd228b5SHeiko Schocher * p u --> P U
939dd228b5SHeiko Schocher * / /
949dd228b5SHeiko Schocher * n N
959dd228b5SHeiko Schocher *
969dd228b5SHeiko Schocher * However, since g's parent might be red, and
979dd228b5SHeiko Schocher * 4) does not allow this, we need to recurse
989dd228b5SHeiko Schocher * at g.
999dd228b5SHeiko Schocher */
1009dd228b5SHeiko Schocher rb_set_parent_color(tmp, gparent, RB_BLACK);
1019dd228b5SHeiko Schocher rb_set_parent_color(parent, gparent, RB_BLACK);
1029dd228b5SHeiko Schocher node = gparent;
1039dd228b5SHeiko Schocher parent = rb_parent(node);
1049dd228b5SHeiko Schocher rb_set_parent_color(node, parent, RB_RED);
1059dd228b5SHeiko Schocher continue;
1069dd228b5SHeiko Schocher }
1079dd228b5SHeiko Schocher
1089dd228b5SHeiko Schocher tmp = parent->rb_right;
1099dd228b5SHeiko Schocher if (node == tmp) {
1109dd228b5SHeiko Schocher /*
1119dd228b5SHeiko Schocher * Case 2 - left rotate at parent
1129dd228b5SHeiko Schocher *
1139dd228b5SHeiko Schocher * G G
1149dd228b5SHeiko Schocher * / \ / \
1159dd228b5SHeiko Schocher * p U --> n U
1169dd228b5SHeiko Schocher * \ /
1179dd228b5SHeiko Schocher * n p
1189dd228b5SHeiko Schocher *
1199dd228b5SHeiko Schocher * This still leaves us in violation of 4), the
1209dd228b5SHeiko Schocher * continuation into Case 3 will fix that.
1219dd228b5SHeiko Schocher */
1229dd228b5SHeiko Schocher parent->rb_right = tmp = node->rb_left;
1239dd228b5SHeiko Schocher node->rb_left = parent;
1249dd228b5SHeiko Schocher if (tmp)
1259dd228b5SHeiko Schocher rb_set_parent_color(tmp, parent,
1269dd228b5SHeiko Schocher RB_BLACK);
1279dd228b5SHeiko Schocher rb_set_parent_color(parent, node, RB_RED);
1289dd228b5SHeiko Schocher augment_rotate(parent, node);
1299dd228b5SHeiko Schocher parent = node;
1309dd228b5SHeiko Schocher tmp = node->rb_right;
1319dd228b5SHeiko Schocher }
1329dd228b5SHeiko Schocher
1339dd228b5SHeiko Schocher /*
1349dd228b5SHeiko Schocher * Case 3 - right rotate at gparent
1359dd228b5SHeiko Schocher *
1369dd228b5SHeiko Schocher * G P
1379dd228b5SHeiko Schocher * / \ / \
1389dd228b5SHeiko Schocher * p U --> n g
1399dd228b5SHeiko Schocher * / \
1409dd228b5SHeiko Schocher * n U
1419dd228b5SHeiko Schocher */
1429dd228b5SHeiko Schocher gparent->rb_left = tmp; /* == parent->rb_right */
1439dd228b5SHeiko Schocher parent->rb_right = gparent;
1449dd228b5SHeiko Schocher if (tmp)
1459dd228b5SHeiko Schocher rb_set_parent_color(tmp, gparent, RB_BLACK);
1469dd228b5SHeiko Schocher __rb_rotate_set_parents(gparent, parent, root, RB_RED);
1479dd228b5SHeiko Schocher augment_rotate(gparent, parent);
1489dd228b5SHeiko Schocher break;
1499dd228b5SHeiko Schocher } else {
1509dd228b5SHeiko Schocher tmp = gparent->rb_left;
1519dd228b5SHeiko Schocher if (tmp && rb_is_red(tmp)) {
1529dd228b5SHeiko Schocher /* Case 1 - color flips */
1539dd228b5SHeiko Schocher rb_set_parent_color(tmp, gparent, RB_BLACK);
1549dd228b5SHeiko Schocher rb_set_parent_color(parent, gparent, RB_BLACK);
1559dd228b5SHeiko Schocher node = gparent;
1569dd228b5SHeiko Schocher parent = rb_parent(node);
1579dd228b5SHeiko Schocher rb_set_parent_color(node, parent, RB_RED);
1589dd228b5SHeiko Schocher continue;
1599dd228b5SHeiko Schocher }
1609dd228b5SHeiko Schocher
1619dd228b5SHeiko Schocher tmp = parent->rb_left;
1629dd228b5SHeiko Schocher if (node == tmp) {
1639dd228b5SHeiko Schocher /* Case 2 - right rotate at parent */
1649dd228b5SHeiko Schocher parent->rb_left = tmp = node->rb_right;
1659dd228b5SHeiko Schocher node->rb_right = parent;
1669dd228b5SHeiko Schocher if (tmp)
1679dd228b5SHeiko Schocher rb_set_parent_color(tmp, parent,
1689dd228b5SHeiko Schocher RB_BLACK);
1699dd228b5SHeiko Schocher rb_set_parent_color(parent, node, RB_RED);
1709dd228b5SHeiko Schocher augment_rotate(parent, node);
1719dd228b5SHeiko Schocher parent = node;
1729dd228b5SHeiko Schocher tmp = node->rb_left;
1739dd228b5SHeiko Schocher }
1749dd228b5SHeiko Schocher
1759dd228b5SHeiko Schocher /* Case 3 - left rotate at gparent */
1769dd228b5SHeiko Schocher gparent->rb_right = tmp; /* == parent->rb_left */
1779dd228b5SHeiko Schocher parent->rb_left = gparent;
1789dd228b5SHeiko Schocher if (tmp)
1799dd228b5SHeiko Schocher rb_set_parent_color(tmp, gparent, RB_BLACK);
1809dd228b5SHeiko Schocher __rb_rotate_set_parents(gparent, parent, root, RB_RED);
1819dd228b5SHeiko Schocher augment_rotate(gparent, parent);
1829dd228b5SHeiko Schocher break;
1839dd228b5SHeiko Schocher }
1849dd228b5SHeiko Schocher }
1859dd228b5SHeiko Schocher }
1869dd228b5SHeiko Schocher
1879dd228b5SHeiko Schocher /*
1889dd228b5SHeiko Schocher * Inline version for rb_erase() use - we want to be able to inline
1899dd228b5SHeiko Schocher * and eliminate the dummy_rotate callback there
1909dd228b5SHeiko Schocher */
1919dd228b5SHeiko Schocher static __always_inline void
____rb_erase_color(struct rb_node * parent,struct rb_root * root,void (* augment_rotate)(struct rb_node * old,struct rb_node * new))1929dd228b5SHeiko Schocher ____rb_erase_color(struct rb_node *parent, struct rb_root *root,
1939dd228b5SHeiko Schocher void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
1949dd228b5SHeiko Schocher {
1959dd228b5SHeiko Schocher struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
1969dd228b5SHeiko Schocher
1979dd228b5SHeiko Schocher while (true) {
1989dd228b5SHeiko Schocher /*
1999dd228b5SHeiko Schocher * Loop invariants:
2009dd228b5SHeiko Schocher * - node is black (or NULL on first iteration)
2019dd228b5SHeiko Schocher * - node is not the root (parent is not NULL)
2029dd228b5SHeiko Schocher * - All leaf paths going through parent and node have a
2039dd228b5SHeiko Schocher * black node count that is 1 lower than other leaf paths.
2049dd228b5SHeiko Schocher */
2059dd228b5SHeiko Schocher sibling = parent->rb_right;
2069dd228b5SHeiko Schocher if (node != sibling) { /* node == parent->rb_left */
2079dd228b5SHeiko Schocher if (rb_is_red(sibling)) {
2089dd228b5SHeiko Schocher /*
2099dd228b5SHeiko Schocher * Case 1 - left rotate at parent
2109dd228b5SHeiko Schocher *
2119dd228b5SHeiko Schocher * P S
2129dd228b5SHeiko Schocher * / \ / \
2139dd228b5SHeiko Schocher * N s --> p Sr
2149dd228b5SHeiko Schocher * / \ / \
2159dd228b5SHeiko Schocher * Sl Sr N Sl
2169dd228b5SHeiko Schocher */
2179dd228b5SHeiko Schocher parent->rb_right = tmp1 = sibling->rb_left;
2189dd228b5SHeiko Schocher sibling->rb_left = parent;
2199dd228b5SHeiko Schocher rb_set_parent_color(tmp1, parent, RB_BLACK);
2209dd228b5SHeiko Schocher __rb_rotate_set_parents(parent, sibling, root,
2219dd228b5SHeiko Schocher RB_RED);
2229dd228b5SHeiko Schocher augment_rotate(parent, sibling);
2239dd228b5SHeiko Schocher sibling = tmp1;
2249dd228b5SHeiko Schocher }
2259dd228b5SHeiko Schocher tmp1 = sibling->rb_right;
2269dd228b5SHeiko Schocher if (!tmp1 || rb_is_black(tmp1)) {
2279dd228b5SHeiko Schocher tmp2 = sibling->rb_left;
2289dd228b5SHeiko Schocher if (!tmp2 || rb_is_black(tmp2)) {
2299dd228b5SHeiko Schocher /*
2309dd228b5SHeiko Schocher * Case 2 - sibling color flip
2319dd228b5SHeiko Schocher * (p could be either color here)
2329dd228b5SHeiko Schocher *
2339dd228b5SHeiko Schocher * (p) (p)
2349dd228b5SHeiko Schocher * / \ / \
2359dd228b5SHeiko Schocher * N S --> N s
2369dd228b5SHeiko Schocher * / \ / \
2379dd228b5SHeiko Schocher * Sl Sr Sl Sr
2389dd228b5SHeiko Schocher *
2399dd228b5SHeiko Schocher * This leaves us violating 5) which
2409dd228b5SHeiko Schocher * can be fixed by flipping p to black
2419dd228b5SHeiko Schocher * if it was red, or by recursing at p.
2429dd228b5SHeiko Schocher * p is red when coming from Case 1.
2439dd228b5SHeiko Schocher */
2449dd228b5SHeiko Schocher rb_set_parent_color(sibling, parent,
2459dd228b5SHeiko Schocher RB_RED);
2469dd228b5SHeiko Schocher if (rb_is_red(parent))
2479dd228b5SHeiko Schocher rb_set_black(parent);
2489dd228b5SHeiko Schocher else {
2499dd228b5SHeiko Schocher node = parent;
2509dd228b5SHeiko Schocher parent = rb_parent(node);
25178acc472SPeter Tyser if (parent)
2529dd228b5SHeiko Schocher continue;
25378acc472SPeter Tyser }
2549dd228b5SHeiko Schocher break;
25578acc472SPeter Tyser }
2569dd228b5SHeiko Schocher /*
2579dd228b5SHeiko Schocher * Case 3 - right rotate at sibling
2589dd228b5SHeiko Schocher * (p could be either color here)
2599dd228b5SHeiko Schocher *
2609dd228b5SHeiko Schocher * (p) (p)
2619dd228b5SHeiko Schocher * / \ / \
2629dd228b5SHeiko Schocher * N S --> N Sl
2639dd228b5SHeiko Schocher * / \ \
2649dd228b5SHeiko Schocher * sl Sr s
2659dd228b5SHeiko Schocher * \
2669dd228b5SHeiko Schocher * Sr
2679dd228b5SHeiko Schocher */
2689dd228b5SHeiko Schocher sibling->rb_left = tmp1 = tmp2->rb_right;
2699dd228b5SHeiko Schocher tmp2->rb_right = sibling;
2709dd228b5SHeiko Schocher parent->rb_right = tmp2;
2719dd228b5SHeiko Schocher if (tmp1)
2729dd228b5SHeiko Schocher rb_set_parent_color(tmp1, sibling,
2739dd228b5SHeiko Schocher RB_BLACK);
2749dd228b5SHeiko Schocher augment_rotate(sibling, tmp2);
2759dd228b5SHeiko Schocher tmp1 = sibling;
2769dd228b5SHeiko Schocher sibling = tmp2;
2779dd228b5SHeiko Schocher }
2789dd228b5SHeiko Schocher /*
2799dd228b5SHeiko Schocher * Case 4 - left rotate at parent + color flips
2809dd228b5SHeiko Schocher * (p and sl could be either color here.
2819dd228b5SHeiko Schocher * After rotation, p becomes black, s acquires
2829dd228b5SHeiko Schocher * p's color, and sl keeps its color)
2839dd228b5SHeiko Schocher *
2849dd228b5SHeiko Schocher * (p) (s)
2859dd228b5SHeiko Schocher * / \ / \
2869dd228b5SHeiko Schocher * N S --> P Sr
2879dd228b5SHeiko Schocher * / \ / \
2889dd228b5SHeiko Schocher * (sl) sr N (sl)
2899dd228b5SHeiko Schocher */
2909dd228b5SHeiko Schocher parent->rb_right = tmp2 = sibling->rb_left;
2919dd228b5SHeiko Schocher sibling->rb_left = parent;
2929dd228b5SHeiko Schocher rb_set_parent_color(tmp1, sibling, RB_BLACK);
2939dd228b5SHeiko Schocher if (tmp2)
2949dd228b5SHeiko Schocher rb_set_parent(tmp2, parent);
2959dd228b5SHeiko Schocher __rb_rotate_set_parents(parent, sibling, root,
2969dd228b5SHeiko Schocher RB_BLACK);
2979dd228b5SHeiko Schocher augment_rotate(parent, sibling);
2989dd228b5SHeiko Schocher break;
2999dd228b5SHeiko Schocher } else {
3009dd228b5SHeiko Schocher sibling = parent->rb_left;
3019dd228b5SHeiko Schocher if (rb_is_red(sibling)) {
3029dd228b5SHeiko Schocher /* Case 1 - right rotate at parent */
3039dd228b5SHeiko Schocher parent->rb_left = tmp1 = sibling->rb_right;
3049dd228b5SHeiko Schocher sibling->rb_right = parent;
3059dd228b5SHeiko Schocher rb_set_parent_color(tmp1, parent, RB_BLACK);
3069dd228b5SHeiko Schocher __rb_rotate_set_parents(parent, sibling, root,
3079dd228b5SHeiko Schocher RB_RED);
3089dd228b5SHeiko Schocher augment_rotate(parent, sibling);
3099dd228b5SHeiko Schocher sibling = tmp1;
3109dd228b5SHeiko Schocher }
3119dd228b5SHeiko Schocher tmp1 = sibling->rb_left;
3129dd228b5SHeiko Schocher if (!tmp1 || rb_is_black(tmp1)) {
3139dd228b5SHeiko Schocher tmp2 = sibling->rb_right;
3149dd228b5SHeiko Schocher if (!tmp2 || rb_is_black(tmp2)) {
3159dd228b5SHeiko Schocher /* Case 2 - sibling color flip */
3169dd228b5SHeiko Schocher rb_set_parent_color(sibling, parent,
3179dd228b5SHeiko Schocher RB_RED);
3189dd228b5SHeiko Schocher if (rb_is_red(parent))
3199dd228b5SHeiko Schocher rb_set_black(parent);
3209dd228b5SHeiko Schocher else {
3219dd228b5SHeiko Schocher node = parent;
3229dd228b5SHeiko Schocher parent = rb_parent(node);
32378acc472SPeter Tyser if (parent)
3249dd228b5SHeiko Schocher continue;
3259dd228b5SHeiko Schocher }
3269dd228b5SHeiko Schocher break;
3279dd228b5SHeiko Schocher }
3289dd228b5SHeiko Schocher /* Case 3 - right rotate at sibling */
3299dd228b5SHeiko Schocher sibling->rb_right = tmp1 = tmp2->rb_left;
3309dd228b5SHeiko Schocher tmp2->rb_left = sibling;
3319dd228b5SHeiko Schocher parent->rb_left = tmp2;
3329dd228b5SHeiko Schocher if (tmp1)
3339dd228b5SHeiko Schocher rb_set_parent_color(tmp1, sibling,
3349dd228b5SHeiko Schocher RB_BLACK);
3359dd228b5SHeiko Schocher augment_rotate(sibling, tmp2);
3369dd228b5SHeiko Schocher tmp1 = sibling;
3379dd228b5SHeiko Schocher sibling = tmp2;
3389dd228b5SHeiko Schocher }
3399dd228b5SHeiko Schocher /* Case 4 - left rotate at parent + color flips */
3409dd228b5SHeiko Schocher parent->rb_left = tmp2 = sibling->rb_right;
3419dd228b5SHeiko Schocher sibling->rb_right = parent;
3429dd228b5SHeiko Schocher rb_set_parent_color(tmp1, sibling, RB_BLACK);
3439dd228b5SHeiko Schocher if (tmp2)
3449dd228b5SHeiko Schocher rb_set_parent(tmp2, parent);
3459dd228b5SHeiko Schocher __rb_rotate_set_parents(parent, sibling, root,
3469dd228b5SHeiko Schocher RB_BLACK);
3479dd228b5SHeiko Schocher augment_rotate(parent, sibling);
3489dd228b5SHeiko Schocher break;
3499dd228b5SHeiko Schocher }
3509dd228b5SHeiko Schocher }
3519dd228b5SHeiko Schocher }
3529dd228b5SHeiko Schocher
3539dd228b5SHeiko Schocher /* Non-inline version for rb_erase_augmented() use */
__rb_erase_color(struct rb_node * parent,struct rb_root * root,void (* augment_rotate)(struct rb_node * old,struct rb_node * new))3549dd228b5SHeiko Schocher void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
3559dd228b5SHeiko Schocher void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
35678acc472SPeter Tyser {
3579dd228b5SHeiko Schocher ____rb_erase_color(parent, root, augment_rotate);
35878acc472SPeter Tyser }
3599dd228b5SHeiko Schocher EXPORT_SYMBOL(__rb_erase_color);
3609dd228b5SHeiko Schocher
3619dd228b5SHeiko Schocher /*
3629dd228b5SHeiko Schocher * Non-augmented rbtree manipulation functions.
3639dd228b5SHeiko Schocher *
3649dd228b5SHeiko Schocher * We use dummy augmented callbacks here, and have the compiler optimize them
3659dd228b5SHeiko Schocher * out of the rb_insert_color() and rb_erase() function definitions.
3669dd228b5SHeiko Schocher */
3679dd228b5SHeiko Schocher
dummy_propagate(struct rb_node * node,struct rb_node * stop)3689dd228b5SHeiko Schocher static inline void dummy_propagate(struct rb_node *node, struct rb_node *stop) {}
dummy_copy(struct rb_node * old,struct rb_node * new)3699dd228b5SHeiko Schocher static inline void dummy_copy(struct rb_node *old, struct rb_node *new) {}
dummy_rotate(struct rb_node * old,struct rb_node * new)3709dd228b5SHeiko Schocher static inline void dummy_rotate(struct rb_node *old, struct rb_node *new) {}
3719dd228b5SHeiko Schocher
3729dd228b5SHeiko Schocher static const struct rb_augment_callbacks dummy_callbacks = {
3739dd228b5SHeiko Schocher dummy_propagate, dummy_copy, dummy_rotate
3749dd228b5SHeiko Schocher };
37578acc472SPeter Tyser
rb_insert_color(struct rb_node * node,struct rb_root * root)37678acc472SPeter Tyser void rb_insert_color(struct rb_node *node, struct rb_root *root)
37778acc472SPeter Tyser {
3789dd228b5SHeiko Schocher __rb_insert(node, root, dummy_rotate);
37978acc472SPeter Tyser }
3809dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_insert_color);
38178acc472SPeter Tyser
rb_erase(struct rb_node * node,struct rb_root * root)38278acc472SPeter Tyser void rb_erase(struct rb_node *node, struct rb_root *root)
38378acc472SPeter Tyser {
3849dd228b5SHeiko Schocher struct rb_node *rebalance;
3859dd228b5SHeiko Schocher rebalance = __rb_erase_augmented(node, root, &dummy_callbacks);
3869dd228b5SHeiko Schocher if (rebalance)
3879dd228b5SHeiko Schocher ____rb_erase_color(rebalance, root, dummy_rotate);
38878acc472SPeter Tyser }
3899dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_erase);
39078acc472SPeter Tyser
3919dd228b5SHeiko Schocher /*
3929dd228b5SHeiko Schocher * Augmented rbtree manipulation functions.
3939dd228b5SHeiko Schocher *
3949dd228b5SHeiko Schocher * This instantiates the same __always_inline functions as in the non-augmented
3959dd228b5SHeiko Schocher * case, but this time with user-defined callbacks.
3969dd228b5SHeiko Schocher */
39778acc472SPeter Tyser
__rb_insert_augmented(struct rb_node * node,struct rb_root * root,void (* augment_rotate)(struct rb_node * old,struct rb_node * new))3989dd228b5SHeiko Schocher void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
3999dd228b5SHeiko Schocher void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
40078acc472SPeter Tyser {
4019dd228b5SHeiko Schocher __rb_insert(node, root, augment_rotate);
40278acc472SPeter Tyser }
4039dd228b5SHeiko Schocher EXPORT_SYMBOL(__rb_insert_augmented);
40478acc472SPeter Tyser
40578acc472SPeter Tyser /*
40678acc472SPeter Tyser * This function returns the first node (in sort order) of the tree.
40778acc472SPeter Tyser */
rb_first(const struct rb_root * root)4089dd228b5SHeiko Schocher struct rb_node *rb_first(const struct rb_root *root)
40978acc472SPeter Tyser {
41078acc472SPeter Tyser struct rb_node *n;
41178acc472SPeter Tyser
41278acc472SPeter Tyser n = root->rb_node;
41378acc472SPeter Tyser if (!n)
41478acc472SPeter Tyser return NULL;
41578acc472SPeter Tyser while (n->rb_left)
41678acc472SPeter Tyser n = n->rb_left;
41778acc472SPeter Tyser return n;
41878acc472SPeter Tyser }
4199dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_first);
42078acc472SPeter Tyser
rb_last(const struct rb_root * root)4219dd228b5SHeiko Schocher struct rb_node *rb_last(const struct rb_root *root)
42278acc472SPeter Tyser {
42378acc472SPeter Tyser struct rb_node *n;
42478acc472SPeter Tyser
42578acc472SPeter Tyser n = root->rb_node;
42678acc472SPeter Tyser if (!n)
42778acc472SPeter Tyser return NULL;
42878acc472SPeter Tyser while (n->rb_right)
42978acc472SPeter Tyser n = n->rb_right;
43078acc472SPeter Tyser return n;
43178acc472SPeter Tyser }
4329dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_last);
43378acc472SPeter Tyser
rb_next(const struct rb_node * node)4349dd228b5SHeiko Schocher struct rb_node *rb_next(const struct rb_node *node)
43578acc472SPeter Tyser {
43678acc472SPeter Tyser struct rb_node *parent;
43778acc472SPeter Tyser
4389dd228b5SHeiko Schocher if (RB_EMPTY_NODE(node))
43978acc472SPeter Tyser return NULL;
44078acc472SPeter Tyser
4419dd228b5SHeiko Schocher /*
4429dd228b5SHeiko Schocher * If we have a right-hand child, go down and then left as far
4439dd228b5SHeiko Schocher * as we can.
4449dd228b5SHeiko Schocher */
44578acc472SPeter Tyser if (node->rb_right) {
44678acc472SPeter Tyser node = node->rb_right;
44778acc472SPeter Tyser while (node->rb_left)
44878acc472SPeter Tyser node=node->rb_left;
4499dd228b5SHeiko Schocher return (struct rb_node *)node;
45078acc472SPeter Tyser }
45178acc472SPeter Tyser
4529dd228b5SHeiko Schocher /*
4539dd228b5SHeiko Schocher * No right-hand children. Everything down and left is smaller than us,
4549dd228b5SHeiko Schocher * so any 'next' node must be in the general direction of our parent.
4559dd228b5SHeiko Schocher * Go up the tree; any time the ancestor is a right-hand child of its
4569dd228b5SHeiko Schocher * parent, keep going up. First time it's a left-hand child of its
4579dd228b5SHeiko Schocher * parent, said parent is our 'next' node.
4589dd228b5SHeiko Schocher */
45978acc472SPeter Tyser while ((parent = rb_parent(node)) && node == parent->rb_right)
46078acc472SPeter Tyser node = parent;
46178acc472SPeter Tyser
46278acc472SPeter Tyser return parent;
46378acc472SPeter Tyser }
4649dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_next);
46578acc472SPeter Tyser
rb_prev(const struct rb_node * node)4669dd228b5SHeiko Schocher struct rb_node *rb_prev(const struct rb_node *node)
46778acc472SPeter Tyser {
46878acc472SPeter Tyser struct rb_node *parent;
46978acc472SPeter Tyser
4709dd228b5SHeiko Schocher if (RB_EMPTY_NODE(node))
47178acc472SPeter Tyser return NULL;
47278acc472SPeter Tyser
4739dd228b5SHeiko Schocher /*
4749dd228b5SHeiko Schocher * If we have a left-hand child, go down and then right as far
4759dd228b5SHeiko Schocher * as we can.
4769dd228b5SHeiko Schocher */
47778acc472SPeter Tyser if (node->rb_left) {
47878acc472SPeter Tyser node = node->rb_left;
47978acc472SPeter Tyser while (node->rb_right)
48078acc472SPeter Tyser node=node->rb_right;
4819dd228b5SHeiko Schocher return (struct rb_node *)node;
48278acc472SPeter Tyser }
48378acc472SPeter Tyser
4849dd228b5SHeiko Schocher /*
4859dd228b5SHeiko Schocher * No left-hand children. Go up till we find an ancestor which
4869dd228b5SHeiko Schocher * is a right-hand child of its parent.
4879dd228b5SHeiko Schocher */
48878acc472SPeter Tyser while ((parent = rb_parent(node)) && node == parent->rb_left)
48978acc472SPeter Tyser node = parent;
49078acc472SPeter Tyser
49178acc472SPeter Tyser return parent;
49278acc472SPeter Tyser }
4939dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_prev);
49478acc472SPeter Tyser
rb_replace_node(struct rb_node * victim,struct rb_node * new,struct rb_root * root)49578acc472SPeter Tyser void rb_replace_node(struct rb_node *victim, struct rb_node *new,
49678acc472SPeter Tyser struct rb_root *root)
49778acc472SPeter Tyser {
49878acc472SPeter Tyser struct rb_node *parent = rb_parent(victim);
49978acc472SPeter Tyser
50078acc472SPeter Tyser /* Set the surrounding nodes to point to the replacement */
5019dd228b5SHeiko Schocher __rb_change_child(victim, new, parent, root);
50278acc472SPeter Tyser if (victim->rb_left)
50378acc472SPeter Tyser rb_set_parent(victim->rb_left, new);
50478acc472SPeter Tyser if (victim->rb_right)
50578acc472SPeter Tyser rb_set_parent(victim->rb_right, new);
50678acc472SPeter Tyser
50778acc472SPeter Tyser /* Copy the pointers/colour from the victim to the replacement */
50878acc472SPeter Tyser *new = *victim;
50978acc472SPeter Tyser }
5109dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_replace_node);
5119dd228b5SHeiko Schocher
rb_left_deepest_node(const struct rb_node * node)5129dd228b5SHeiko Schocher static struct rb_node *rb_left_deepest_node(const struct rb_node *node)
5139dd228b5SHeiko Schocher {
5149dd228b5SHeiko Schocher for (;;) {
5159dd228b5SHeiko Schocher if (node->rb_left)
5169dd228b5SHeiko Schocher node = node->rb_left;
5179dd228b5SHeiko Schocher else if (node->rb_right)
5189dd228b5SHeiko Schocher node = node->rb_right;
5199dd228b5SHeiko Schocher else
5209dd228b5SHeiko Schocher return (struct rb_node *)node;
5219dd228b5SHeiko Schocher }
5229dd228b5SHeiko Schocher }
5239dd228b5SHeiko Schocher
rb_next_postorder(const struct rb_node * node)5249dd228b5SHeiko Schocher struct rb_node *rb_next_postorder(const struct rb_node *node)
5259dd228b5SHeiko Schocher {
5269dd228b5SHeiko Schocher const struct rb_node *parent;
5279dd228b5SHeiko Schocher if (!node)
5289dd228b5SHeiko Schocher return NULL;
5299dd228b5SHeiko Schocher parent = rb_parent(node);
5309dd228b5SHeiko Schocher
5319dd228b5SHeiko Schocher /* If we're sitting on node, we've already seen our children */
5329dd228b5SHeiko Schocher if (parent && node == parent->rb_left && parent->rb_right) {
5339dd228b5SHeiko Schocher /* If we are the parent's left node, go to the parent's right
5349dd228b5SHeiko Schocher * node then all the way down to the left */
5359dd228b5SHeiko Schocher return rb_left_deepest_node(parent->rb_right);
5369dd228b5SHeiko Schocher } else
5379dd228b5SHeiko Schocher /* Otherwise we are the parent's right node, and the parent
5389dd228b5SHeiko Schocher * should be next */
5399dd228b5SHeiko Schocher return (struct rb_node *)parent;
5409dd228b5SHeiko Schocher }
5419dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_next_postorder);
5429dd228b5SHeiko Schocher
rb_first_postorder(const struct rb_root * root)5439dd228b5SHeiko Schocher struct rb_node *rb_first_postorder(const struct rb_root *root)
5449dd228b5SHeiko Schocher {
5459dd228b5SHeiko Schocher if (!root->rb_node)
5469dd228b5SHeiko Schocher return NULL;
5479dd228b5SHeiko Schocher
5489dd228b5SHeiko Schocher return rb_left_deepest_node(root->rb_node);
5499dd228b5SHeiko Schocher }
5509dd228b5SHeiko Schocher EXPORT_SYMBOL(rb_first_postorder);
551