Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 | // SPDX-License-Identifier: GPL-2.0-only #include <asm/bug.h> #include <linux/rbtree_augmented.h> #include "drbd_interval.h" /* * interval_end - return end of @node */ static inline sector_t interval_end(struct rb_node *node) { struct drbd_interval *this = rb_entry(node, struct drbd_interval, rb); return this->end; } #define NODE_END(node) ((node)->sector + ((node)->size >> 9)) RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks, struct drbd_interval, rb, sector_t, end, NODE_END); /* * drbd_insert_interval - insert a new interval into a tree */ bool drbd_insert_interval(struct rb_root *root, struct drbd_interval *this) { struct rb_node **new = &root->rb_node, *parent = NULL; sector_t this_end = this->sector + (this->size >> 9); BUG_ON(!IS_ALIGNED(this->size, 512)); while (*new) { struct drbd_interval *here = rb_entry(*new, struct drbd_interval, rb); parent = *new; if (here->end < this_end) here->end = this_end; if (this->sector < here->sector) new = &(*new)->rb_left; else if (this->sector > here->sector) new = &(*new)->rb_right; else if (this < here) new = &(*new)->rb_left; else if (this > here) new = &(*new)->rb_right; else return false; } this->end = this_end; rb_link_node(&this->rb, parent, new); rb_insert_augmented(&this->rb, root, &augment_callbacks); return true; } /** * drbd_contains_interval - check if a tree contains a given interval * @root: red black tree root * @sector: start sector of @interval * @interval: may be an invalid pointer * * Returns if the tree contains the node @interval with start sector @start. * Does not dereference @interval until @interval is known to be a valid object * in @tree. Returns %false if @interval is in the tree but with a different * sector number. */ bool drbd_contains_interval(struct rb_root *root, sector_t sector, struct drbd_interval *interval) { struct rb_node *node = root->rb_node; while (node) { struct drbd_interval *here = rb_entry(node, struct drbd_interval, rb); if (sector < here->sector) node = node->rb_left; else if (sector > here->sector) node = node->rb_right; else if (interval < here) node = node->rb_left; else if (interval > here) node = node->rb_right; else return true; } return false; } /* * drbd_remove_interval - remove an interval from a tree */ void drbd_remove_interval(struct rb_root *root, struct drbd_interval *this) { /* avoid endless loop */ if (drbd_interval_empty(this)) return; rb_erase_augmented(&this->rb, root, &augment_callbacks); } /** * drbd_find_overlap - search for an interval overlapping with [sector, sector + size) * @root: red black tree root * @sector: start sector * @size: size, aligned to 512 bytes * * Returns an interval overlapping with [sector, sector + size), or NULL if * there is none. When there is more than one overlapping interval in the * tree, the interval with the lowest start sector is returned, and all other * overlapping intervals will be on the right side of the tree, reachable with * rb_next(). */ struct drbd_interval * drbd_find_overlap(struct rb_root *root, sector_t sector, unsigned int size) { struct rb_node *node = root->rb_node; struct drbd_interval *overlap = NULL; sector_t end = sector + (size >> 9); BUG_ON(!IS_ALIGNED(size, 512)); while (node) { struct drbd_interval *here = rb_entry(node, struct drbd_interval, rb); if (node->rb_left && sector < interval_end(node->rb_left)) { /* Overlap if any must be on left side */ node = node->rb_left; } else if (here->sector < end && sector < here->sector + (here->size >> 9)) { overlap = here; break; } else if (sector >= here->sector) { /* Overlap if any must be on right side */ node = node->rb_right; } else break; } return overlap; } struct drbd_interval * drbd_next_overlap(struct drbd_interval *i, sector_t sector, unsigned int size) { sector_t end = sector + (size >> 9); struct rb_node *node; for (;;) { node = rb_next(&i->rb); if (!node) return NULL; i = rb_entry(node, struct drbd_interval, rb); if (i->sector >= end) return NULL; if (sector < i->sector + (i->size >> 9)) return i; } } |