- Some example of insert and search follows here. The search is a plain
- normal search over an ordered tree. The insert instead must be implemented
- int two steps: as first thing the code must insert the element in
- order as a red leaf in the tree, then the support library function
- rb_insert_color() must be called. Such function will do the
- not trivial work to rebalance the rbtree if necessary.
-
------------------------------------------------------------------------
-static inline struct page * rb_search_page_cache(struct inode * inode,
- unsigned long offset)
-{
- struct rb_node * n = inode->i_rb_page_cache.rb_node;
- struct page * page;
-
- while (n)
- {
- page = rb_entry(n, struct page, rb_page_cache);
-
- if (offset < page->offset)
- n = n->rb_left;
- else if (offset > page->offset)
- n = n->rb_right;
- else
- return page;
- }
- return NULL;
-}
-
-static inline struct page * __rb_insert_page_cache(struct inode * inode,
- unsigned long offset,
- struct rb_node * node)
-{
- struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
- struct rb_node * parent = NULL;
- struct page * page;
-
- while (*p)
- {
- parent = *p;
- page = rb_entry(parent, struct page, rb_page_cache);
-
- if (offset < page->offset)
- p = &(*p)->rb_left;
- else if (offset > page->offset)
- p = &(*p)->rb_right;
- else
- return page;
- }
-
- rb_link_node(node, parent, p);
-
- return NULL;
-}
-
-static inline struct page * rb_insert_page_cache(struct inode * inode,
- unsigned long offset,
- struct rb_node * node)
-{
- struct page * ret;
- if ((ret = __rb_insert_page_cache(inode, offset, node)))
- goto out;
- rb_insert_color(node, &inode->i_rb_page_cache);
- out:
- return ret;
-}
------------------------------------------------------------------------