fs: Turn do_invalidatepage() into folio_invalidate()

Take a folio instead of a page, fix the types of the offset & length,
and export it to filesystems.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

include/linux/mm.h

@@ -1939,9 +1939,6 @@ int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
 			struct page **pages);
 struct page *get_dump_page(unsigned long addr);
 
-extern void do_invalidatepage(struct page *page, unsigned int offset,
-			      unsigned int length);
-
 bool folio_mark_dirty(struct folio *folio);
 bool set_page_dirty(struct page *page);
 int set_page_dirty_lock(struct page *page);

include/linux/pagemap.h

@@ -893,6 +893,7 @@ static inline void cancel_dirty_page(struct page *page)
 }
 bool folio_clear_dirty_for_io(struct folio *folio);
 bool clear_page_dirty_for_io(struct page *page);
+void folio_invalidate(struct folio *folio, size_t offset, size_t length);
 int __must_check folio_write_one(struct folio *folio);
 static inline int __must_check write_one_page(struct page *page)
 {

mm/readahead.c

@@ -51,7 +51,7 @@ static void read_cache_pages_invalidate_page(struct address_space *mapping,
 		if (!trylock_page(page))
 			BUG();
 		page->mapping = mapping;
-		do_invalidatepage(page, 0, PAGE_SIZE);
+		folio_invalidate(page_folio(page), 0, PAGE_SIZE);
 		page->mapping = NULL;
 		unlock_page(page);
 	}

mm/truncate.c

@@ -138,33 +138,33 @@ static int invalidate_exceptional_entry2(struct address_space *mapping,
 }
 
 /**
- * do_invalidatepage - invalidate part or all of a page
- * @page: the page which is affected
+ * folio_invalidate - Invalidate part or all of a folio.
+ * @folio: The folio which is affected.
  * @offset: start of the range to invalidate
  * @length: length of the range to invalidate
  *
- * do_invalidatepage() is called when all or part of the page has become
+ * folio_invalidate() is called when all or part of the folio has become
  * invalidated by a truncate operation.
  *
- * do_invalidatepage() does not have to release all buffers, but it must
+ * folio_invalidate() does not have to release all buffers, but it must
  * ensure that no dirty buffer is left outside @offset and that no I/O
  * is underway against any of the blocks which are outside the truncation
  * point.  Because the caller is about to free (and possibly reuse) those
  * blocks on-disk.
  */
-void do_invalidatepage(struct page *page, unsigned int offset,
-		       unsigned int length)
+void folio_invalidate(struct folio *folio, size_t offset, size_t length)
 {
 	void (*invalidatepage)(struct page *, unsigned int, unsigned int);
 
-	invalidatepage = page->mapping->a_ops->invalidatepage;
+	invalidatepage = folio->mapping->a_ops->invalidatepage;
 #ifdef CONFIG_BLOCK
 	if (!invalidatepage)
 		invalidatepage = block_invalidatepage;
 #endif
 	if (invalidatepage)
-		(*invalidatepage)(page, offset, length);
+		(*invalidatepage)(&folio->page, offset, length);
 }
+EXPORT_SYMBOL_GPL(folio_invalidate);
 
 /*
  * If truncate cannot remove the fs-private metadata from the page, the page
@@ -182,7 +182,7 @@ static void truncate_cleanup_folio(struct folio *folio)
 		unmap_mapping_folio(folio);
 
 	if (folio_has_private(folio))
-		do_invalidatepage(&folio->page, 0, folio_size(folio));
+		folio_invalidate(folio, 0, folio_size(folio));
 
 	/*
 	 * Some filesystems seem to re-dirty the page even after
@@ -264,7 +264,7 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
 	folio_zero_range(folio, offset, length);
 
 	if (folio_has_private(folio))
-		do_invalidatepage(&folio->page, offset, length);
+		folio_invalidate(folio, offset, length);
 	if (!folio_test_large(folio))
 		return true;
 	if (split_huge_page(&folio->page) == 0)