[PATCH 4.15 156/168] ipv6: sr: fix seg6 encap performances with TSO enabled

From: Greg Kroah-Hartman
Date: Tue Apr 10 2018 - 19:08:56 EST


4.15-stable review patch. If anyone has any objections, please let me know.

------------------

From: David Lebrun <dlebrun@xxxxxxxxxx>


[ Upstream commit 5807b22c9164a21cd1077a9bc587f0bba361f72d ]

Enabling TSO can lead to abysmal performances when using seg6 in
encap mode, such as with the ixgbe driver. This patch adds a call to
iptunnel_handle_offloads() to remove the encapsulation bit if needed.

Before:
root@comp4-seg6bpf:~# iperf3 -c fc00::55
Connecting to host fc00::55, port 5201
[ 4] local fc45::4 port 36592 connected to fc00::55 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 196 KBytes 1.60 Mbits/sec 47 6.66 KBytes
[ 4] 1.00-2.00 sec 304 KBytes 2.49 Mbits/sec 100 5.33 KBytes
[ 4] 2.00-3.00 sec 284 KBytes 2.32 Mbits/sec 92 5.33 KBytes

After:
root@comp4-seg6bpf:~# iperf3 -c fc00::55
Connecting to host fc00::55, port 5201
[ 4] local fc45::4 port 43062 connected to fc00::55 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 1.03 GBytes 8.89 Gbits/sec 0 743 KBytes
[ 4] 1.00-2.00 sec 1.03 GBytes 8.87 Gbits/sec 0 743 KBytes
[ 4] 2.00-3.00 sec 1.03 GBytes 8.87 Gbits/sec 0 743 KBytes

Reported-by: Tom Herbert <tom@xxxxxxxxxxxxxx>
Fixes: 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Signed-off-by: David Lebrun <dlebrun@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/seg6_iptunnel.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

--- a/net/ipv6/seg6_iptunnel.c
+++ b/net/ipv6/seg6_iptunnel.c
@@ -16,6 +16,7 @@
#include <linux/net.h>
#include <linux/module.h>
#include <net/ip.h>
+#include <net/ip_tunnels.h>
#include <net/lwtunnel.h>
#include <net/netevent.h>
#include <net/netns/generic.h>
@@ -211,11 +212,6 @@ static int seg6_do_srh(struct sk_buff *s

tinfo = seg6_encap_lwtunnel(dst->lwtstate);

- if (likely(!skb->encapsulation)) {
- skb_reset_inner_headers(skb);
- skb->encapsulation = 1;
- }
-
switch (tinfo->mode) {
case SEG6_IPTUN_MODE_INLINE:
if (skb->protocol != htons(ETH_P_IPV6))
@@ -224,10 +220,12 @@ static int seg6_do_srh(struct sk_buff *s
err = seg6_do_srh_inline(skb, tinfo->srh);
if (err)
return err;
-
- skb_reset_inner_headers(skb);
break;
case SEG6_IPTUN_MODE_ENCAP:
+ err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
+ if (err)
+ return err;
+
if (skb->protocol == htons(ETH_P_IPV6))
proto = IPPROTO_IPV6;
else if (skb->protocol == htons(ETH_P_IP))
@@ -239,6 +237,8 @@ static int seg6_do_srh(struct sk_buff *s
if (err)
return err;

+ skb_set_inner_transport_header(skb, skb_transport_offset(skb));
+ skb_set_inner_protocol(skb, skb->protocol);
skb->protocol = htons(ETH_P_IPV6);
break;
case SEG6_IPTUN_MODE_L2ENCAP:
@@ -262,8 +262,6 @@ static int seg6_do_srh(struct sk_buff *s
ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
skb_set_transport_header(skb, sizeof(struct ipv6hdr));

- skb_set_inner_protocol(skb, skb->protocol);
-
return 0;
}