[ovs-dev] [PATCH v3 03/28] datapath: backport: tunnels: Remove encapsulation offloads on decap.

Pravin B Shelar pshelar at ovn.org
Sat Jul 2 00:58:32 UTC 2016


Following patch backports updated iptunnel pull function.
Also brings in following upstream fix:

    commit a09a4c8dd1ec7f830e1fb9e59eb72bddc965d168
    Author: Jesse Gross <jesse at kernel.org>

    tunnels: Remove encapsulation offloads on decap.

    If a packet is either locally encapsulated or processed through GRO
    it is marked with the offloads that it requires. However, when it is
    decapsulated these tunnel offload indications are not removed. This
    means that if we receive an encapsulated TCP packet, aggregate it with
    GRO, decapsulate, and retransmit the resulting frame on a NIC that does
    not support encapsulation, we won't be able to take advantage of hardware
    offloads even though it is just a simple TCP packet at this point.

    This fixes the problem by stripping off encapsulation offload indications
    when packets are decapsulated.

    The performance impacts of this bug are significant. In a test where a
    Geneve encapsulated TCP stream is sent to a hypervisor, GRO'ed, decapsulated,
    and bridged to a VM performance is improved by 60% (5Gbps->8Gbps) as a
    result of avoiding unnecessary segmentation at the VM tap interface.

    Reported-by: Ramu Ramamurthy <sramamur at linux.vnet.ibm.com>
    Fixes: 68c33163 ("v4 GRE: Add TCP segmentation offload for GRE")
    Signed-off-by: Jesse Gross <jesse at kernel.org>
    Signed-off-by: David S. Miller <davem at davemloft.net>

Signed-off-by: Pravin B Shelar <pshelar at ovn.org>
Acked-by: Jesse Gross <jesse at kernel.org>
---
 acinclude.m4                                   |  3 ++-
 datapath/linux/compat/include/net/ip_tunnels.h | 15 +++++++++++++++
 datapath/linux/compat/ip_tunnels_core.c        |  2 +-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/acinclude.m4 b/acinclude.m4
index 65d41f0..263c31d 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -432,7 +432,8 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/net/inetpeer.h], [vif],
                   [OVS_DEFINE([HAVE_INETPEER_VIF_SUPPORT])])
 
-  OVS_GREP_IFELSE([$KSRC/include/net/dst_metadata.h], [metadata_dst])
+  OVS_GREP_IFELSE([$KSRC/include/net/ip_tunnels.h], [iptunnel_pull_offloads],
+                  [OVS_DEFINE([HAVE_METADATA_DST])])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/net.h], [sock_create_kern.*net],
                   [OVS_DEFINE([HAVE_SOCK_CREATE_KERN_NET])])
diff --git a/datapath/linux/compat/include/net/ip_tunnels.h b/datapath/linux/compat/include/net/ip_tunnels.h
index bf67ac4..26c9041 100644
--- a/datapath/linux/compat/include/net/ip_tunnels.h
+++ b/datapath/linux/compat/include/net/ip_tunnels.h
@@ -339,4 +339,19 @@ struct net *rpl_ip_tunnel_get_link_net(const struct net_device *dev);
 int rpl___ip_tunnel_change_mtu(struct net_device *dev, int new_mtu, bool strict);
 #endif
 
+static inline int iptunnel_pull_offloads(struct sk_buff *skb)
+{
+	if (skb_is_gso(skb)) {
+		int err;
+
+		err = skb_unclone(skb, GFP_ATOMIC);
+		if (unlikely(err))
+			return err;
+		skb_shinfo(skb)->gso_type &= ~(NETIF_F_GSO_ENCAP_ALL >>
+					       NETIF_F_GSO_SHIFT);
+	}
+
+	skb->encapsulation = 0;
+	return 0;
+}
 #endif /* __NET_IP_TUNNELS_H */
diff --git a/datapath/linux/compat/ip_tunnels_core.c b/datapath/linux/compat/ip_tunnels_core.c
index c5fb2b7..ee4fadc 100644
--- a/datapath/linux/compat/ip_tunnels_core.c
+++ b/datapath/linux/compat/ip_tunnels_core.c
@@ -171,7 +171,7 @@ int rpl___iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
 	skb_set_queue_mapping(skb, 0);
 	skb_scrub_packet(skb, xnet);
 
-	return 0;
+	return iptunnel_pull_offloads(skb);
 }
 EXPORT_SYMBOL_GPL(rpl___iptunnel_pull_header);
 
-- 
1.9.1




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