1 files changed, 68 insertions, 0 deletions
diff --git a/sys/compat/linuxkpi/common/include/linux/pagevec.h b/sys/compat/linuxkpi/common/include/linux/pagevec.h
index 9ba8ff8effa0..0a952e965b5a 100644
--- a/sys/compat/linuxkpi/common/include/linux/pagevec.h
+++ b/sys/compat/linuxkpi/common/include/linux/pagevec.h
@@ -66,4 +66,72 @@ check_move_unevictable_pages(struct pagevec *pvec)
 {
 }
 
+/*
+ * struct folio
+ *
+ * On Linux, `struct folio` replaces `struct page`. To manage a list of folios,
+ * there is `struct folio_batch` on top of this, which replaces `struct
+ * pagevec` above.
+ *
+ * Here is the original description when `struct folio` was added to the Linux
+ * kernel:
+ *   "A struct folio is a new abstraction to replace the venerable struct page.
+ *   A function which takes a struct folio argument declares that it will
+ *   operate on the entire (possibly compound) page, not just PAGE_SIZE bytes.
+ *   In return, the caller guarantees that the pointer it is passing does not
+ *   point to a tail page.  No change to generated code."
+ */
+
+struct folio;
+
+struct folio_batch {
+	uint8_t	nr;
+	struct folio *folios[PAGEVEC_SIZE];
+};
+
+static inline void
+folio_batch_init(struct folio_batch *fbatch)
+{
+	fbatch->nr = 0;
+}
+
+static inline void
+folio_batch_reinit(struct folio_batch *fbatch)
+{
+	fbatch->nr = 0;
+}
+
+static inline unsigned int
+folio_batch_count(struct folio_batch *fbatch)
+{
+	return (fbatch->nr);
+}
+
+static inline unsigned int
+folio_batch_space(struct folio_batch *fbatch)
+{
+	return (PAGEVEC_SIZE - fbatch->nr);
+}
+
+static inline unsigned int
+folio_batch_add(struct folio_batch *fbatch, struct folio *folio)
+{
+	KASSERT(
+	    fbatch->nr < PAGEVEC_SIZE,
+	    ("struct folio_batch %p is full", fbatch));
+
+	fbatch->folios[fbatch->nr++] = folio;
+
+	return (folio_batch_space(fbatch));
+}
+
+void __folio_batch_release(struct folio_batch *fbatch);
+
+static inline void
+folio_batch_release(struct folio_batch *fbatch)
+{
+	if (folio_batch_count(fbatch))
+		__folio_batch_release(fbatch);
+}
+
 #endif	/* _LINUXKPI_LINUX_PAGEVEC_H_ */