ksmbd: Add missing set_freezable() for freezable kthread

The kernel thread function ksmbd_conn_handler_loop() invokes
the try_to_freeze() in its loop. But all the kernel threads are
non-freezable by default. So if we want to make a kernel thread to be
freezable, we have to invoke set_freezable() explicitly.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/connection.c

@@ -284,6 +284,7 @@ int ksmbd_conn_handler_loop(void *p)
 		goto out;
 
 	conn->last_active = jiffies;
+	set_freezable();
 	while (ksmbd_conn_alive(conn)) {
 		if (try_to_freeze())
 			continue;