mm/interval_tree.c

root/mm/interval_tree.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * mm/interval_tree.c - interval tree for mapping->i_mmap
 *
 * Copyright (C) 2012, Michel Lespinasse <walken@google.com>
 */

#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/rmap.h>
#include <linux/interval_tree_generic.h>

static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
{
        return v->vm_pgoff;
}

static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
{
        return v->vm_pgoff + vma_pages(v) - 1;
}

INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
                     unsigned long, shared.rb_subtree_last,
                     vma_start_pgoff, vma_last_pgoff, /* empty */, vma_interval_tree)

/* Insert node immediately after prev in the interval tree */
void vma_interval_tree_insert_after(struct vm_area_struct *node,
                                    struct vm_area_struct *prev,
                                    struct rb_root_cached *root)
{
        struct rb_node **link;
        struct vm_area_struct *parent;
        unsigned long last = vma_last_pgoff(node);

        VM_BUG_ON_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);

        if (!prev->shared.rb.rb_right) {
                parent = prev;
                link = &prev->shared.rb.rb_right;
        } else {
                parent = rb_entry(prev->shared.rb.rb_right,
                                  struct vm_area_struct, shared.rb);
                if (parent->shared.rb_subtree_last < last)
                        parent->shared.rb_subtree_last = last;
                while (parent->shared.rb.rb_left) {
                        parent = rb_entry(parent->shared.rb.rb_left,
                                struct vm_area_struct, shared.rb);
                        if (parent->shared.rb_subtree_last < last)
                                parent->shared.rb_subtree_last = last;
                }
                link = &parent->shared.rb.rb_left;
        }

        node->shared.rb_subtree_last = last;
        rb_link_node(&node->shared.rb, &parent->shared.rb, link);
        rb_insert_augmented(&node->shared.rb, &root->rb_root,
                            &vma_interval_tree_augment);
}

static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
{
        return vma_start_pgoff(avc->vma);
}

static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
{
        return vma_last_pgoff(avc->vma);
}

INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last,
                     avc_start_pgoff, avc_last_pgoff,
                     static inline, __anon_vma_interval_tree)

void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
                                   struct rb_root_cached *root)
{
#ifdef CONFIG_DEBUG_VM_RB
        node->cached_vma_start = avc_start_pgoff(node);
        node->cached_vma_last = avc_last_pgoff(node);
#endif
        __anon_vma_interval_tree_insert(node, root);
}

void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
                                   struct rb_root_cached *root)
{
        __anon_vma_interval_tree_remove(node, root);
}

struct anon_vma_chain *
anon_vma_interval_tree_iter_first(struct rb_root_cached *root,
                                  unsigned long first, unsigned long last)
{
        return __anon_vma_interval_tree_iter_first(root, first, last);
}

struct anon_vma_chain *
anon_vma_interval_tree_iter_next(struct anon_vma_chain *node,
                                 unsigned long first, unsigned long last)
{
        return __anon_vma_interval_tree_iter_next(node, first, last);
}

#ifdef CONFIG_DEBUG_VM_RB
void anon_vma_interval_tree_verify(struct anon_vma_chain *node)
{
        WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node));
        WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node));
}
#endif
Linux
