Subject: [PATCH 25/25] Subject: [PATCH 3.14-stable] net: gso: use feature flag argument in all protocol gso handlers

From: Florian Westphal <[email-masked]>
Date: Wed, 26 Aug 2015 22:17:39 -0700

[ Upstream commit 1e16aa3ddf863c6b9f37eddf52503230a62dedb3 ]

skb_gso_segment() has a 'features' argument representing offload features
available to the output path.

A few handlers, e.g. GRE, instead re-fetch the features of skb->dev and use
those instead of the provided ones when handing encapsulation/tunnels.

Depending on dev->hw_enc_features of the output device skb_gso_segment() can
then return NULL even when the caller has disabled all GSO feature bits,
as segmentation of inner header thinks device will take care of segmentation.

This e.g. affects the tbf scheduler, which will silently drop GRE-encap GSO skbs
that did not fit the remaining token quota as the segmentation does not work
when device supports corresponding hw offload capabilities.

Cc: Pravin B Shelar <[email-masked]>
Signed-off-by: Florian Westphal <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
[jay.vosburgh: backported to 3.14. ]
Signed-off-by: Jay Vosburgh <[email-masked]>
---
 net/ipv4/af_inet.c     | 2 +-
 net/ipv4/gre_offload.c | 2 +-
 net/ipv4/udp.c         | 2 +-
 net/ipv6/ip6_offload.c | 2 +-
 net/mpls/mpls_gso.c    | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 951fe55..f4c804d 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1291,7 +1291,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
 
 	encap = SKB_GSO_CB(skb)->encap_level > 0;
 	if (encap)
-		features = skb->dev->hw_enc_features & netif_skb_features(skb);
+		features &= skb->dev->hw_enc_features;
 	SKB_GSO_CB(skb)->encap_level += ihl;
 
 	skb_reset_transport_header(skb);
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 278836f..0da513e 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -69,7 +69,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 	skb->mac_len = skb_inner_network_offset(skb);
 
 	/* segment inner packet. */
-	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
+	enc_features = skb->dev->hw_enc_features & features;
 	segs = skb_mac_gso_segment(skb, enc_features);
 	if (!segs || IS_ERR(segs)) {
 		skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 947dcae..6970e36 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2517,7 +2517,7 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 	skb->protocol = htons(ETH_P_TEB);
 
 	/* segment inner packet. */
-	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
+	enc_features = skb->dev->hw_enc_features & features;
 	segs = skb_mac_gso_segment(skb, enc_features);
 	if (!segs || IS_ERR(segs)) {
 		skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset,
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index b2f0915..dc46eba 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -112,7 +112,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
 
 	encap = SKB_GSO_CB(skb)->encap_level > 0;
 	if (encap)
-		features = skb->dev->hw_enc_features & netif_skb_features(skb);
+		features &= skb->dev->hw_enc_features;
 	SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h);
 
 	ipv6h = ipv6_hdr(skb);
diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c
index 851cd88..0c970cb 100644
--- a/net/mpls/mpls_gso.c
+++ b/net/mpls/mpls_gso.c
@@ -47,7 +47,7 @@ static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
 	__skb_push(skb, skb->mac_len);
 
 	/* Segment inner packet. */
-	mpls_features = skb->dev->mpls_features & netif_skb_features(skb);
+	mpls_features = skb->dev->mpls_features & features;
 	segs = skb_mac_gso_segment(skb, mpls_features);

-- 
2.1.0