alloc_file(): switch to passing O_... flags instead of FMODE_... mode

... so that it could set both ->f_flags and ->f_mode, without callers
having to set ->f_flags manually.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

mm/shmem.c

@@ -3942,8 +3942,7 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
 	if (IS_ERR(res))
 		goto put_path;
 
-	res = alloc_file(&path, FMODE_WRITE | FMODE_READ,
-		  &shmem_file_operations);
+	res = alloc_file(&path, O_RDWR, &shmem_file_operations);
 	if (IS_ERR(res))
 		goto put_path;