+ list_for_each_entry_safe(page, tmp_page, &fbdefio->pagelist, lru) {
+ lock_page(page);
+ /*
+ * The workqueue callback can be triggered after a
+ * ->page_mkwrite() call but before the PTE has been marked
+ * dirty. In this case page_mkclean() won't "rearm" the page.
+ *
+ * To avoid this, remove those "non-dirty" pages from the
+ * pagelist before calling the driver's callback, then add
+ * them back to get processed on the next work iteration.
+ * At that time, their PTEs will hopefully be dirty for real.
+ */
+ if (!page_mkclean(page))
+ list_move_tail(&page->lru, &non_dirty);
+ unlock_page(page);