[3.13.y-ckt stable] Patch "net: gso: use feature flag argument in all protocol gso handlers" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    net: gso: use feature flag argument in all protocol gso handlers

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt27.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From feb5b95143f2988f00039434bd87773433a3b774 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw at strlen.de>
Date: Wed, 26 Aug 2015 22:17:39 -0700
Subject: net: gso: use feature flag argument in all protocol gso handlers

[ 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 <pshelar at nicira.com>
Signed-off-by: Florian Westphal <fw at strlen.de>
Signed-off-by: David S. Miller <davem at davemloft.net>
[jay.vosburgh: backported to 3.14. ]
Signed-off-by: Jay Vosburgh <jay.vosburgh at canonical.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 7d2d135..7dd59a8 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1294,7 +1294,7 @@ 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 2cd02f3..f70d768 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -72,7 +72,7 @@ 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 78899fa..4e9921b 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 6762299..3a70036 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);


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1.9.1