Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754867AbaANAqM (ORCPT ); Mon, 13 Jan 2014 19:46:12 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:54330 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753752AbaANA2Y (ORCPT ); Mon, 13 Jan 2014 19:28:24 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rusty Russell , Michael Dalton , Eric Dumazet , Jason Wang , "David S. Miller" , "Michael S. Tsirkin" Subject: [PATCH 3.12 32/77] virtio_net: fix error handling for mergeable buffers Date: Mon, 13 Jan 2014 16:27:53 -0800 Message-Id: <20140114002753.417957148@linuxfoundation.org> X-Mailer: git-send-email 1.8.5.1.163.gd7aced9 In-Reply-To: <20140114002752.497010554@linuxfoundation.org> References: <20140114002752.497010554@linuxfoundation.org> User-Agent: quilt/0.61-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" Eric Dumazet noticed that if we encounter an error when processing a mergeable buffer, we don't dequeue all of the buffers from this packet, the result is almost sure to be loss of networking. Fix this issue. Cc: Rusty Russell Cc: Michael Dalton Acked-by: Michael Dalton Cc: Eric Dumazet Cc: Jason Wang Cc: David S. Miller Signed-off-by: Michael S. Tsirkin (cherry picked from commit 8fc3b9e9a229778e5af3aa453c44f1a3857ba769) Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 66 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 46 insertions(+), 20 deletions(-) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -297,26 +297,33 @@ static struct sk_buff *page_to_skb(struc return skb; } -static int receive_mergeable(struct receive_queue *rq, struct sk_buff *skb) +static struct sk_buff *receive_mergeable(struct net_device *dev, + struct receive_queue *rq, + void *buf, + unsigned int len) { - struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb); - struct page *page; - int num_buf, i, len; + struct skb_vnet_hdr *hdr = page_address(buf); + int num_buf = hdr->mhdr.num_buffers; + struct page *page = buf; + struct sk_buff *skb = page_to_skb(rq, page, len); + int i; + + if (unlikely(!skb)) + goto err_skb; - num_buf = hdr->mhdr.num_buffers; while (--num_buf) { i = skb_shinfo(skb)->nr_frags; if (i >= MAX_SKB_FRAGS) { pr_debug("%s: packet too long\n", skb->dev->name); skb->dev->stats.rx_length_errors++; - return -EINVAL; + return NULL; } page = virtqueue_get_buf(rq->vq, &len); if (!page) { - pr_debug("%s: rx error: %d buffers missing\n", - skb->dev->name, hdr->mhdr.num_buffers); - skb->dev->stats.rx_length_errors++; - return -EINVAL; + pr_debug("%s: rx error: %d buffers %d missing\n", + dev->name, hdr->mhdr.num_buffers, num_buf); + dev->stats.rx_length_errors++; + goto err_buf; } if (len > PAGE_SIZE) @@ -326,7 +333,25 @@ static int receive_mergeable(struct rece --rq->num; } - return 0; + return skb; +err_skb: + give_pages(rq, page); + while (--num_buf) { + buf = virtqueue_get_buf(rq->vq, &len); + if (unlikely(!buf)) { + pr_debug("%s: rx error: %d buffers missing\n", + dev->name, num_buf); + dev->stats.rx_length_errors++; + break; + } + page = buf; + give_pages(rq, page); + --rq->num; + } +err_buf: + dev->stats.rx_dropped++; + dev_kfree_skb(skb); + return NULL; } static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len) @@ -354,17 +379,18 @@ static void receive_buf(struct receive_q skb_trim(skb, len); } else { page = buf; - skb = page_to_skb(rq, page, len); - if (unlikely(!skb)) { - dev->stats.rx_dropped++; - give_pages(rq, page); - return; - } - if (vi->mergeable_rx_bufs) - if (receive_mergeable(rq, skb)) { - dev_kfree_skb(skb); + if (vi->mergeable_rx_bufs) { + skb = receive_mergeable(dev, rq, page, len); + if (unlikely(!skb)) + return; + } else { + skb = page_to_skb(rq, page, len); + if (unlikely(!skb)) { + dev->stats.rx_dropped++; + give_pages(rq, page); return; } + } } hdr = skb_vnet_hdr(skb); -- 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/