Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754651AbZAGMXA (ORCPT ); Wed, 7 Jan 2009 07:23:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751481AbZAGMWt (ORCPT ); Wed, 7 Jan 2009 07:22:49 -0500 Received: from rhun.apana.org.au ([64.62.148.172]:59074 "EHLO arnor.apana.org.au" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751094AbZAGMWs (ORCPT ); Wed, 7 Jan 2009 07:22:48 -0500 Date: Wed, 7 Jan 2009 23:22:38 +1100 From: Herbert Xu To: Evgeniy Polyakov Cc: Jens Axboe , Willy Tarreau , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: Data corruption issue with splice() on 2.6.27.10 Message-ID: <20090107122238.GB25673@gondor.apana.org.au> References: <20081224152841.GB13113@1wt.eu> <20090106183223.GA11964@ioremap.net> <20090106183704.GC32491@kernel.dk> <20090107044232.GA22218@gondor.apana.org.au> <20090107112906.GA28161@ioremap.net> <20090107115032.GA25198@gondor.apana.org.au> <20090107115605.GA29250@ioremap.net> <20090107115921.GA25323@gondor.apana.org.au> <20090107121530.GA30164@ioremap.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090107121530.GA30164@ioremap.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1242 Lines: 28 On Wed, Jan 07, 2009 at 03:15:30PM +0300, Evgeniy Polyakov wrote: > > Looks like we are talking about different directions of the dataflow. > I meant that set of pages submitted into the sending part will be copied > if sending interface does not support acceleration, and thus it will > copy part of the page corresponding to the linear part of the skb prior > the transmission, so even if skb will be freed right after that call > (prior data transmission by the hardware), it should not affect copied > data. You must be looking at a different tcp.c than the one I've got because mine clearly always uses skb frags in sendpage regardless of SG support. Yes we will linearize the packet in dev_queue_xmit but as soon as the netdev stops the tx queue you'll get corruption. Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- 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/