From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762747AbZEHDGa (ORCPT ); Thu, 7 May 2009 23:06:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763810AbZEHDCg (ORCPT ); Thu, 7 May 2009 23:02:36 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:52138 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1763786AbZEHDCf (ORCPT ); Thu, 7 May 2009 23:02:35 -0400 Message-ID: <4A03A100.5020308@cn.fujitsu.com> Date: Fri, 08 May 2009 11:03:28 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Steven Rostedt CC: Ingo Molnar , Frederic Weisbecker , LKML Subject: Re: [PATCH 1/2] tracing/events: clean up for ftrace_set_clr_event() References: <4A03998E.3020503@cn.fujitsu.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> @@ -500,30 +505,16 @@ system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, >> if (ret < 0) >> return ret; >> >> - switch (val) { >> - case 0: >> - case 1: >> - break; >> - >> - default: >> + if (val != 0 && val != 1) > > What about "if (val & ~1UL)"? > I tried it just now: text data bss dec hex filename 7480 104 8 7592 1da8 kernel/trace/trace_events.o.orig text data bss dec hex filename 7482 104 8 7594 1daa kernel/trace/trace_events.o It increased text size by 2 bytes, gcc did a better work. ;) And it's not so intuitive what's the limit of val.