From patchwork Tue Jul 9 06:15:20 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Annie.li" X-Patchwork-Id: 257636 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 [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id E64DD2C02CD for ; Tue, 9 Jul 2013 16:20:35 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752957Ab3GIGUd (ORCPT ); Tue, 9 Jul 2013 02:20:33 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:33361 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752272Ab3GIGUb (ORCPT ); Tue, 9 Jul 2013 02:20:31 -0400 Received: from ucsinet22.oracle.com (ucsinet22.oracle.com [156.151.31.94]) by aserp1040.oracle.com (Sentrion-MTA-4.3.1/Sentrion-MTA-4.3.1) with ESMTP id r696KPBO005935 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 9 Jul 2013 06:20:26 GMT Received: from aserz7021.oracle.com (aserz7021.oracle.com [141.146.126.230]) by ucsinet22.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id r696KO1P001819 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 9 Jul 2013 06:20:24 GMT Received: from abhmt106.oracle.com (abhmt106.oracle.com [141.146.116.58]) by aserz7021.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id r696KNJu024402; Tue, 9 Jul 2013 06:20:23 GMT Received: from annie2.cn.oracle.com.com (/10.182.37.169) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 08 Jul 2013 23:20:23 -0700 From: Annie Li To: xen-devel@lists.xensource.com, netdev@vger.kernel.org, Ian.Campbell@citrix.com Cc: konrad.wilk@oracle.com, wei.liu2@citrix.com, annie.li@oracle.com Subject: [PATCH 1/1] xen/netback: correctly calculate required slots of skb. Date: Tue, 9 Jul 2013 14:15:20 +0800 Message-Id: <1373350520-19985-1-git-send-email-annie.li@oracle.com> X-Mailer: git-send-email 1.7.6.4 X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org When counting required slots for skb, netback directly uses DIV_ROUND_UP to get slots required by header data. This is wrong when offset in the page of header data is not zero, and is also inconsistent with following calculation for required slot in netbk_gop_skb. In netbk_gop_skb, required slots are calculated based on offset and len in page of header data. It is possible that required slots here is larger than the one calculated in earlier netbk_count_requests. This inconsistency directly results in rx_req_cons_peek and xen_netbk_rx_ring_full judgement are wrong. Then it comes to situation the ring is actually full, but netback thinks it is not and continues to create responses. This results in response overlaps request in the ring, then grantcopy gets wrong grant reference and throws out error, for example "(XEN) grant_table.c:1763:d0 Bad grant reference 2949120", the grant reference is invalid value here. Netback returns XEN_NETIF_RSP_ERROR(-1) to netfront when grant copy status is error, then netfront gets rx->status (the status is -1, not really data size now), and throws out error, "kernel: net eth1: rx->offset: 0, size: 4294967295". This issue can be reproduced by doing gzip/gunzip in nfs share with mtu = 9000, the guest would panic after running such test for a while. This patch is based on 3.10-rc7. Signed-off-by: Annie Li --- drivers/net/xen-netback/netback.c | 97 +++++++++++++++++++++++++----------- 1 files changed, 67 insertions(+), 30 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 8c20935..7ff9333 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -359,51 +359,88 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head) * the guest. This function is essentially a dry run of * netbk_gop_frag_copy. */ -unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb) +static void netbk_get_slots(struct xenvif *vif, struct sk_buff *skb, + struct page *page, int *copy_off, + unsigned long size, unsigned long offset, + int *head, int *count) { - unsigned int count; - int i, copy_off; + unsigned long bytes; - count = DIV_ROUND_UP(skb_headlen(skb), PAGE_SIZE); + /* Data must not cross a page boundary. */ + BUG_ON(size + offset > PAGE_SIZE<> PAGE_SHIFT; + offset &= ~PAGE_MASK; - if (skb_shinfo(skb)->gso_size) - count++; + while (size > 0) { + BUG_ON(offset >= PAGE_SIZE); + BUG_ON(*copy_off > MAX_BUFFER_OFFSET); - for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { - unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]); - unsigned long offset = skb_shinfo(skb)->frags[i].page_offset; - unsigned long bytes; + bytes = PAGE_SIZE - offset; - offset &= ~PAGE_MASK; + if (bytes > size) + bytes = size; - while (size > 0) { - BUG_ON(offset >= PAGE_SIZE); - BUG_ON(copy_off > MAX_BUFFER_OFFSET); + if (start_new_rx_buffer(*copy_off, bytes, *head)) { + *count = *count + 1; + *copy_off = 0; + } - bytes = PAGE_SIZE - offset; + if (*copy_off + bytes > MAX_BUFFER_OFFSET) + bytes = MAX_BUFFER_OFFSET - *copy_off; - if (bytes > size) - bytes = size; + *copy_off += bytes; - if (start_new_rx_buffer(copy_off, bytes, 0)) { - count++; - copy_off = 0; - } + offset += bytes; + size -= bytes; - if (copy_off + bytes > MAX_BUFFER_OFFSET) - bytes = MAX_BUFFER_OFFSET - copy_off; + /* Next frame */ + if (offset == PAGE_SIZE && size) { + BUG_ON(!PageCompound(page)); + page++; + offset = 0; + } - copy_off += bytes; + if (*head) + *count = *count + 1; + *head = 0; /* There must be something in this buffer now. */ + } +} + +unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb) +{ + int i, copy_off = 0; + int nr_frags = skb_shinfo(skb)->nr_frags; + unsigned char *data; + int head = 1; + unsigned int count = 0; - offset += bytes; - size -= bytes; + if (skb_shinfo(skb)->gso_size) + count++; - if (offset == PAGE_SIZE) - offset = 0; - } + data = skb->data; + while (data < skb_tail_pointer(skb)) { + unsigned int offset = offset_in_page(data); + unsigned int len = PAGE_SIZE - offset; + + if (data + len > skb_tail_pointer(skb)) + len = skb_tail_pointer(skb) - data; + + netbk_get_slots(vif, skb, virt_to_page(data), ©_off, + len, offset, &head, &count); + data += len; + } + + for (i = 0; i < nr_frags; i++) { + netbk_get_slots(vif, skb, + skb_frag_page(&skb_shinfo(skb)->frags[i]), + ©_off, + skb_frag_size(&skb_shinfo(skb)->frags[i]), + skb_shinfo(skb)->frags[i].page_offset, + &head, &count); } + return count; }