linux/mm/interval_tree.c
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   1/*
   2 * mm/interval_tree.c - interval tree for mapping->i_mmap
   3 *
   4 * Copyright (C) 2012, Michel Lespinasse <walken@google.com>
   5 *
   6 * This file is released under the GPL v2.
   7 */
   8
   9#include <linux/mm.h>
  10#include <linux/fs.h>
  11#include <linux/rmap.h>
  12#include <linux/interval_tree_generic.h>
  13
  14static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
  15{
  16        return v->vm_pgoff;
  17}
  18
  19static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
  20{
  21        return v->vm_pgoff + ((v->vm_end - v->vm_start) >> PAGE_SHIFT) - 1;
  22}
  23
  24INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.linear.rb,
  25                     unsigned long, shared.linear.rb_subtree_last,
  26                     vma_start_pgoff, vma_last_pgoff,, vma_interval_tree)
  27
  28/* Insert node immediately after prev in the interval tree */
  29void vma_interval_tree_insert_after(struct vm_area_struct *node,
  30                                    struct vm_area_struct *prev,
  31                                    struct rb_root *root)
  32{
  33        struct rb_node **link;
  34        struct vm_area_struct *parent;
  35        unsigned long last = vma_last_pgoff(node);
  36
  37        VM_BUG_ON(vma_start_pgoff(node) != vma_start_pgoff(prev));
  38
  39        if (!prev->shared.linear.rb.rb_right) {
  40                parent = prev;
  41                link = &prev->shared.linear.rb.rb_right;
  42        } else {
  43                parent = rb_entry(prev->shared.linear.rb.rb_right,
  44                                  struct vm_area_struct, shared.linear.rb);
  45                if (parent->shared.linear.rb_subtree_last < last)
  46                        parent->shared.linear.rb_subtree_last = last;
  47                while (parent->shared.linear.rb.rb_left) {
  48                        parent = rb_entry(parent->shared.linear.rb.rb_left,
  49                                struct vm_area_struct, shared.linear.rb);
  50                        if (parent->shared.linear.rb_subtree_last < last)
  51                                parent->shared.linear.rb_subtree_last = last;
  52                }
  53                link = &parent->shared.linear.rb.rb_left;
  54        }
  55
  56        node->shared.linear.rb_subtree_last = last;
  57        rb_link_node(&node->shared.linear.rb, &parent->shared.linear.rb, link);
  58        rb_insert_augmented(&node->shared.linear.rb, root,
  59                            &vma_interval_tree_augment);
  60}
  61
  62static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
  63{
  64        return vma_start_pgoff(avc->vma);
  65}
  66
  67static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
  68{
  69        return vma_last_pgoff(avc->vma);
  70}
  71
  72INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last,
  73                     avc_start_pgoff, avc_last_pgoff,
  74                     static inline, __anon_vma_interval_tree)
  75
  76void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
  77                                   struct rb_root *root)
  78{
  79#ifdef CONFIG_DEBUG_VM_RB
  80        node->cached_vma_start = avc_start_pgoff(node);
  81        node->cached_vma_last = avc_last_pgoff(node);
  82#endif
  83        __anon_vma_interval_tree_insert(node, root);
  84}
  85
  86void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
  87                                   struct rb_root *root)
  88{
  89        __anon_vma_interval_tree_remove(node, root);
  90}
  91
  92struct anon_vma_chain *
  93anon_vma_interval_tree_iter_first(struct rb_root *root,
  94                                  unsigned long first, unsigned long last)
  95{
  96        return __anon_vma_interval_tree_iter_first(root, first, last);
  97}
  98
  99struct anon_vma_chain *
 100anon_vma_interval_tree_iter_next(struct anon_vma_chain *node,
 101                                 unsigned long first, unsigned long last)
 102{
 103        return __anon_vma_interval_tree_iter_next(node, first, last);
 104}
 105
 106#ifdef CONFIG_DEBUG_VM_RB
 107void anon_vma_interval_tree_verify(struct anon_vma_chain *node)
 108{
 109        WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node));
 110        WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node));
 111}
 112#endif
 113
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