On Tue, May 18, 2021 at 12:38:46PM +0200, Vlastimil Babka wrote:

quoted

-int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
+int __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
 			 unsigned int flags)
 {
-	struct folio *folio = page_folio(page);
-
 	if (fault_flag_allow_retry_first(flags)) {
 		/*
 		 * CAUTION! In this case, mmap_lock is not released

A bit later in this branch, 'page' is accessed, but it no longer exists. And
thus as expected, it doesn't compile. Assuming it's fixed later, but
bisectability etc...

Oops.  Thanks for catching that; I've reordered this patch and the
folio_wait_locked() patch, which makes the entire problem go away.