[PATCH] mm: cleanup rmap

	if (atomic_inc_and_test(&page->_mapcount)) {

		struct anon_vma *anon_vma = vma->anon_vma;

		pgoff_t index;

		BUG_ON(!anon_vma);

		anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;

		page->mapping = (struct address_space *) anon_vma;

		index = (address - vma->vm_start) >> PAGE_SHIFT;

		index += vma->vm_pgoff;

		index >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;

		page->index = index;

		page->index = linear_page_index(vma, address);

		inc_page_state(nr_mapped);

	}