mm/interval_tree.c

   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
  14 static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
  15 {
  16         return v->vm_pgoff;
  17 }
  18
  19 static 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
  24 INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
  25                      unsigned long, shared.rb_subtree_last,
  26                      vma_start_pgoff, vma_last_pgoff,, vma_interval_tree)
  27
  28 /* Insert node immediately after prev in the interval tree */
  29 void vma_interval_tree_insert_after(struct vm_area_struct *node,
  30                                     struct vm_area_struct *prev,
  31                                     struct rb_root_cached *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(vma_start_pgoff(node) != vma_start_pgoff(prev), node);
  38
  39         if (!prev->shared.rb.rb_right) {
  40                 parent = prev;
  41                 link = &prev->shared.rb.rb_right;
  42         } else {
  43                 parent = rb_entry(prev->shared.rb.rb_right,
  44                                   struct vm_area_struct, shared.rb);
  45                 if (parent->shared.rb_subtree_last < last)
  46                         parent->shared.rb_subtree_last = last;
  47                 while (parent->shared.rb.rb_left) {
  48                         parent = rb_entry(parent->shared.rb.rb_left,
  49                                 struct vm_area_struct, shared.rb);
  50                         if (parent->shared.rb_subtree_last < last)
  51                                 parent->shared.rb_subtree_last = last;
  52                 }
  53                 link = &parent->shared.rb.rb_left;
  54         }
  55
  56         node->shared.rb_subtree_last = last;
  57         rb_link_node(&node->shared.rb, &parent->shared.rb, link);
  58         rb_insert_augmented(&node->shared.rb, &root->rb_root,
  59                             &vma_interval_tree_augment);
  60 }
  61
  62 static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
  63 {
  64         return vma_start_pgoff(avc->vma);
  65 }
  66
  67 static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
  68 {
  69         return vma_last_pgoff(avc->vma);
  70 }
  71
  72 INTERVAL_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
  76 void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
  77                                    struct rb_root_cached *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
  86 void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
  87                                    struct rb_root_cached *root)
  88 {
  89         __anon_vma_interval_tree_remove(node, root);
  90 }
  91
  92 struct anon_vma_chain *
  93 anon_vma_interval_tree_iter_first(struct rb_root_cached *root,
  94                                   unsigned long first, unsigned long last)
  95 {
  96         return __anon_vma_interval_tree_iter_first(root, first, last);
  97 }
  98
  99 struct anon_vma_chain *
 100 anon_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
 107 void 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