From patchwork Sat Jan 24 00:10:53 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Snyder X-Patchwork-Id: 20136 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id DD589DE098 for ; Sat, 24 Jan 2009 11:11:03 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758219AbZAXALA (ORCPT ); Fri, 23 Jan 2009 19:11:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755938AbZAXALA (ORCPT ); Fri, 23 Jan 2009 19:11:00 -0500 Received: from ovro.ovro.caltech.edu ([192.100.16.2]:37183 "EHLO ovro.ovro.caltech.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753234AbZAXAK7 (ORCPT ); Fri, 23 Jan 2009 19:10:59 -0500 Received: from ovro.caltech.edu (desk1.correlator.pvt [192.168.17.65]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ovro.ovro.caltech.edu (Postfix) with ESMTP id BDD769F8006; Fri, 23 Jan 2009 16:10:54 -0800 (PST) Date: Fri, 23 Jan 2009 16:10:53 -0800 From: Ira Snyder To: linux-kernel@vger.kernel.org, Mark McLoughlin , Rusty Russell , netdev@vger.kernel.org, "David S. Miller" Subject: [PATCH] virtio_net: use correct accessors for scatterlists Message-ID: <20090124001053.GA20156@ovro.caltech.edu> Mail-Followup-To: linux-kernel@vger.kernel.org, Mark McLoughlin , Rusty Russell , netdev@vger.kernel.org, "David S. Miller" MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.17+20080114 (2008-01-14) X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0 (ovro.ovro.caltech.edu); Fri, 23 Jan 2009 16:10:54 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Without this fix, virtio_net makes incorrect usage of scatterlists. It sets the end of the scatterlist chain after the first element, despite the fact that more entries come after it. If you try to run dma_map_sg() on one of the scatterlists given to you by add_buf(), you will get a null pointer oops. Signed-off-by: Ira W. Snyder --- I found this problem while working on implementing virtio-over-PCI as suggested by Arnd Bergmann, David Miller, and others. drivers/net/virtio_net.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 43f6523..67ea2cf 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -286,7 +286,7 @@ static void try_fill_recv_maxbufs(struct virtnet_info *vi) skb_put(skb, MAX_PACKET_LEN); hdr = skb_vnet_hdr(skb); - sg_init_one(sg, hdr, sizeof(*hdr)); + sg_set_buf(sg, hdr, sizeof(*hdr)); if (vi->big_packets) { for (i = 0; i < MAX_SKB_FRAGS; i++) { @@ -487,9 +487,9 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb) /* Encode metadata header at front. */ if (vi->mergeable_rx_bufs) - sg_init_one(sg, mhdr, sizeof(*mhdr)); + sg_set_buf(sg, mhdr, sizeof(*mhdr)); else - sg_init_one(sg, hdr, sizeof(*hdr)); + sg_set_buf(sg, hdr, sizeof(*hdr)); num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;