Index: sys/compat/linuxkpi/common/include/linux/mm.h
===================================================================
--- sys/compat/linuxkpi/common/include/linux/mm.h
+++ sys/compat/linuxkpi/common/include/linux/mm.h
@@ -517,4 +517,14 @@
 	return (page_address(&folio->page));
 }
 
+static inline bool
+folio_mapped(struct folio *folio)
+{
+#ifdef PAGE_IS_LKPI_PAGE
+	return (pmap_page_is_mapped(folio->page.vm_page));
+#else
+	return (pmap_page_is_mapped(&folio->page));
+#endif
+}
+
 #endif					/* _LINUXKPI_LINUX_MM_H_ */
Index: sys/compat/linuxkpi/common/include/linux/page-flags.h
===================================================================
--- sys/compat/linuxkpi/common/include/linux/page-flags.h
+++ sys/compat/linuxkpi/common/include/linux/page-flags.h
@@ -38,4 +38,12 @@
 	      const struct page *: (const struct folio *)(p), \
 	      struct page *: (struct folio *)(p)))
 
+static inline struct page *
+folio_page(struct folio *folio, int n)
+{
+	KASSERT(n == 0, ("%s: n = %d but only n = 0 supported\n", __func__, n));
+
+	return (&folio->page);
+}
+
 #endif	/* _LINUXKPI_LINUX_PAGEFLAGS_H_ */
Index: sys/compat/linuxkpi/common/include/linux/pagemap.h
===================================================================
--- sys/compat/linuxkpi/common/include/linux/pagemap.h
+++ sys/compat/linuxkpi/common/include/linux/pagemap.h
@@ -35,6 +35,34 @@
 
 struct folio_batch;
 
+static inline struct page *
+folio_file_page(struct folio *folio, pgoff_t index)
+{
+	return (folio_page(folio, index & (folio_nr_pages(folio) - 1)));
+}
+
+static inline void
+folio_lock(struct folio *folio)
+{
+#ifdef PAGE_IS_LKPI_PAGE
+	if (!vm_page_tryxbusy(folio->page.vm_page))
+		vm_page_busy_sleep(folio->page.vm_page, __func__, 0);
+#else
+	if (!vm_page_tryxbusy(&folio->page))
+		vm_page_busy_sleep(&folio->page, __func__, 0);
+#endif
+}
+
+static inline void
+folio_unlock(struct folio *folio)
+{
+#ifdef PAGE_IS_LKPI_PAGE
+	vm_page_xunbusy(folio->page.vm_page);
+#else
+	vm_page_xunbusy(&folio->page);
+#endif
+}
+
 #define	invalidate_mapping_pages(...) \
   linux_invalidate_mapping_pages(__VA_ARGS__)