Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757287Ab2EYRPJ (ORCPT ); Fri, 25 May 2012 13:15:09 -0400 Received: from terminus.zytor.com ([198.137.202.10]:41835 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752729Ab2EYRPG (ORCPT ); Fri, 25 May 2012 13:15:06 -0400 Message-ID: <4FBFBDCE.6030104@zytor.com> Date: Fri, 25 May 2012 10:13:50 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Thavatchai Makphaibulcboke CC: Lasse Collin , "lethal@linux-sh.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "x86@kernel.org" , "kaloz@openwrt.org" , "matt.fleming@intel.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-s390@vger.kernel.org" , "linux-sh@vger.kernel.org" , "linux@arm.linux.org.uk" , "schwidefsky@de.ibm.com" , "heiko.carstens@de.ibm.com" , "linux390@de.ibm.com" Subject: Re: [PATCH] lib/decompress_unxz.c: removing all memory helper functions References: <1337875436-27640-1-git-send-email-tmac@hp.com> <20120525113432.3beea6ed@tukaani.org> <4FBFB3F3.1000606@hp.com> <4FBFBBF3.3090204@hp.com> In-Reply-To: <4FBFBBF3.3090204@hp.com> X-Enigmail-Version: 1.4.1 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: 920 Lines: 25 On 05/25/2012 10:05 AM, Thavatchai Makphaibulcboke wrote: >> We could do that. But according to the comment in the original >> implementation, there seems to be a concern regarding its performance >> speed. If you believe all archs' memcpy would give comparable >> performance to the memmove. then I could do that. >> > > Also how about the case for overlapping buffer, especially when the > destination is at a higher address? I do not believe memcpy guarantee > to work. memcpy() is not guaranteed to work for any overlap; that is what memmove() is for. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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/