Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757043Ab3FCKwn (ORCPT ); Mon, 3 Jun 2013 06:52:43 -0400 Received: from intranet.asianux.com ([58.214.24.6]:36995 "EHLO intranet.asianux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755863Ab3FCKwk (ORCPT ); Mon, 3 Jun 2013 06:52:40 -0400 X-Spam-Score: -100.8 Message-ID: <51AC7546.4010002@asianux.com> Date: Mon, 03 Jun 2013 18:51:50 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Andy Shevchenko CC: edumazet@google.com, Pravin Shelar , mgorman@suse.de, David Miller , Andrew Morton , "linux-kernel@vger.kernel.org" , netdev , Ben Hutchings Subject: Re: [PATCH] include/linux/skbuff.h: using '0xffff' instead of '~0U' References: <51A6EBC5.7040601@asianux.com> <51AC60AA.8010107@asianux.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1071 Lines: 32 On 06/03/2013 06:14 PM, Andy Shevchenko wrote: > On Mon, Jun 3, 2013 at 12:23 PM, Chen Gang wrote: >> On 06/01/2013 05:05 AM, Andy Shevchenko wrote: > >>> Why not "(u16)~0" ? >> We'd better to give a meaningful name to it just like Ben said. > > Yeah, you could give a name, though I don't see this needs for > constants like (u16)~0. It's a usual way to mark some values > uninitialized. > Just an example from kernel: > > /* This is limited by 16 bit "slot" numbers, > * and by available on-disk context storage. > * > * Also (u16)~0 is special (denotes a "free" extent). > After "fgrep -rn 'u16' * | fgrep '~0'", it seems better to define a meaningful macro for it (e.g. "#define SKB_HEADER_WAS_UNSET 0xffff"). Thanks. -- Chen Gang Asianux Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/