fs/btrfs/common/rbtree-utils.c

   1 /*
   2  * Copyright (C) 2014 Facebook.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/errno.h>
  20 #include "rbtree-utils.h"
  21
  22 int rb_insert(struct rb_root *root, struct rb_node *node,
  23               rb_compare_nodes comp)
  24 {
  25         struct rb_node **p = &root->rb_node;
  26         struct rb_node *parent = NULL;
  27         int ret;
  28
  29         while(*p) {
  30                 parent = *p;
  31
  32                 ret = comp(parent, node);
  33                 if (ret < 0)
  34                         p = &(*p)->rb_left;
  35                 else if (ret > 0)
  36                         p = &(*p)->rb_right;
  37                 else
  38                         return -EEXIST;
  39         }
  40
  41         rb_link_node(node, parent, p);
  42         rb_insert_color(node, root);
  43         return 0;
  44 }
  45
  46 struct rb_node *rb_search(struct rb_root *root, void *key, rb_compare_keys comp,
  47                           struct rb_node **next_ret)
  48 {
  49         struct rb_node *n = root->rb_node;
  50         struct rb_node *parent = NULL;
  51         int ret = 0;
  52
  53         while(n) {
  54                 parent = n;
  55
  56                 ret = comp(n, key);
  57                 if (ret < 0)
  58                         n = n->rb_left;
  59                 else if (ret > 0)
  60                         n = n->rb_right;
  61                 else
  62                         return n;
  63         }
  64
  65         if (!next_ret)
  66                 return NULL;
  67
  68         if (parent && ret > 0)
  69                 parent = rb_next(parent);
  70
  71         *next_ret = parent;
  72         return NULL;
  73 }
  74
  75 void rb_free_nodes(struct rb_root *root, rb_free_node free_node)
  76 {
  77         struct rb_node *node;
  78
  79         while ((node = rb_first(root))) {
  80                 rb_erase(node, root);
  81                 free_node(node);
  82         }
  83 }