From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [PATCH 3/3] virtio_net: Fix skb->csum_start computation Date: Thu, 29 May 2008 17:31:16 +1000 Message-ID: <200805291731.17131.rusty@rustcorp.com.au> References: <1211887247-31979-1-git-send-email-markmc@redhat.com> <1211887247-31979-3-git-send-email-markmc@redhat.com> <1211887247-31979-4-git-send-email-markmc@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, Herbert Xu To: Mark McLoughlin Return-path: Received: from ozlabs.org ([203.10.76.45]:55281 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751646AbYE2Hdw (ORCPT ); Thu, 29 May 2008 03:33:52 -0400 In-Reply-To: <1211887247-31979-4-git-send-email-markmc@redhat.com> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Tuesday 27 May 2008 21:20:47 Mark McLoughlin wrote: > hdr->csum_start is the offset from the start of the ethernet > header to the transport layer checksum field. skb->csum_start > is the offset from skb->head. > > skb_partial_csum_set() assumes that skb->data points to the > ethernet header - i.e. it computes skb->csum_start by adding > the headroom to hdr->csum_start. > > Since eth_type_trans() skb_pull()s the ethernet header, > skb_partial_csum_set() should be called before > eth_type_trans(). As should the rx_bytes += skb->len. Thanks for this! Applied (and 1/3, the typo patch). I'll backport this to -stable, as well. Thanks, Rusty.