[PATCH 6.1 1/4] cifs: fix flushing folio regression for 6.1 backport

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

filemap_get_folio works differenty in 6.1 vs. later kernels
(returning NULL in 6.1 instead of an error).  Add
this minor correction which addresses the regression in the patch:
  cifs: Fix flushing, invalidation and file size with copy_file_range()

Suggested-by: David Howells <dhowells@redhat.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/client/cifsfs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1240,7 +1240,7 @@ static int cifs_flush_folio(struct inode
 	int rc = 0;
 
 	folio = filemap_get_folio(inode->i_mapping, index);
-	if (IS_ERR(folio))
+	if ((!folio) || (IS_ERR(folio)))
 		return 0;
 
 	size = folio_size(folio);