[PATCH v6 1/6] filemap: check compound_head(page)->mapping in filemap_fault()

[Song Liu]

Currently, filemap_fault() avoids trace condition with truncate by
checking page->mapping == mapping. This does not work for compound
pages. This patch let it check compound_head(page)->mapping instead.

Acked-by: Rik van Riel <r...@surriel.com>
Signed-off-by: Song Liu <songliubrav...@fb.com>
---
 mm/filemap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index df2006ba0cfa..f5b79a43946d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2517,7 +2517,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf)
                goto out_retry;
 
        /* Did it get truncated? */
-       if (unlikely(page->mapping != mapping)) {
+       if (unlikely(compound_head(page)->mapping != mapping)) {
                unlock_page(page);
                put_page(page);
                goto retry_find;
-- 
2.17.1