From: Alan Cox Subject: Re: [PATCH 2/3] lib: improve the performance of memcpy and memmove of the general version Date: Sat, 4 Sep 2010 15:41:14 +0100 Message-ID: <20100904154114.19501d6e@lxorguk.ukuu.org.uk> References: <4C7E2CAC.6080102@cn.fujitsu.com> <82mxrzrsvq.fsf@mid.bfk.de> <1283605142.9039.4.camel@ayu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Florian Weimer , miaox@cn.fujitsu.com, Ingo Molnar , Andrew Morton , Chris Mason , "Theodore Ts'o" , Andreas Dilger , Linux Kernel , Linux Btrfs , Linux Ext4 To: Calvin Walton Return-path: Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:39398 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752781Ab0IDOW7 (ORCPT ); Sat, 4 Sep 2010 10:22:59 -0400 In-Reply-To: <1283605142.9039.4.camel@ayu> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sat, 04 Sep 2010 08:59:02 -0400 Calvin Walton wrote: > On Fri, 2010-09-03 at 11:03 +0000, Florian Weimer wrote: > > * Miao Xie: > > > > > EXPORT_SYMBOL(memcpy); > > > > I think you need to change that to EXPORT_SYMBOL_GPL, because the code > > is now licensed under the GPL, and not the GPL plus kernel exceptions > > (whatever they are, but they undoubtly exist), unlike the original > > implementation. > > I wouldn't think so - the intent of EXPORT_SYMBOL_GPL is to mark symbols > that make it obvious that a module was derived from the Linux kernel, as > opposed to some sort of generic driver that was just ported to a new > interface. (It's not foolproof, it's more of a warning to developers.) EXPORT_SYMBOL_GPL was meant for symbols that were clearly internal workings. EXPORT_SYMBOL() doesn't in any way imply or excuse GPL compliance for any derivative work. Using the FSF memcpy seems a good technical idea, and it'll no doubt liven up the proprietary module makers lawyers as it'll make the FSF a party to any infringement disputes 8) Alan