[RFC PATCH 03/31] mm: migrate: Add tmpfs exchange support.

[Zi Yan]

tmpfs uses the same migrate routine as anonymous pages, enabling
exchange pages for it is easy.

Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
 mm/exchange.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/exchange.c b/mm/exchange.c
index 8cf286fc0f10..851f1a99b48b 100644
--- a/mm/exchange.c
+++ b/mm/exchange.c
@@ -466,7 +466,10 @@ static int exchange_from_to_pages(struct page *to_page, struct page *from_page,
 		rc = exchange_page_move_mapping(to_page_mapping, from_page_mapping,
 					to_page, from_page, NULL, NULL, mode, 0, 0);
 	} else {
-		if (to_page_mapping->a_ops->migratepage == buffer_migrate_page) {
+		/* shmem */
+		if (to_page_mapping->a_ops->migratepage == migrate_page)
+			goto exchange_mappings;
+		else if (to_page_mapping->a_ops->migratepage == buffer_migrate_page) {
 
 			if (!page_has_buffers(to_page))
 				goto exchange_mappings;
-- 
2.20.1