This is a note to let you know that I've just added the patch titled

ip6_gre: fix device features for ioctl setup

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: ip6_gre-fix-device-features-for-ioctl-setup.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Sun Dec 31 11:12:48 CET 2017

From: Alexey Kodanev alexey.kodanev@oracle.com Date: Wed, 20 Dec 2017 19:36:03 +0300 Subject: ip6_gre: fix device features for ioctl setup

From: Alexey Kodanev alexey.kodanev@oracle.com

[ Upstream commit e5a9336adb317db55eb3fe8200856096f3c71109 ]

When ip6gre is created using ioctl, its features, such as scatter-gather, GSO and tx-checksumming will be turned off:

# ip -f inet6 tunnel add gre6 mode ip6gre remote fd00::1 # ethtool -k gre6 (truncated output) tx-checksumming: off scatter-gather: off tcp-segmentation-offload: off generic-segmentation-offload: off [requested on]

But when netlink is used, they will be enabled: # ip link add gre6 type ip6gre remote fd00::1 # ethtool -k gre6 (truncated output) tx-checksumming: on scatter-gather: on tcp-segmentation-offload: on generic-segmentation-offload: on

This results in a loss of performance when gre6 is created via ioctl. The issue was found with LTP/gre tests.

Fix it by moving the setup of device features to a separate function and invoke it with ndo_init callback because both netlink and ioctl will eventually call it via register_netdevice():

register_netdevice() - ndo_init() callback -> ip6gre_tunnel_init() or ip6gre_tap_init() - ip6gre_tunnel_init_common() - ip6gre_tnl_init_features()

The moved code also contains two minor style fixes: * removed needless tab from GRE6_FEATURES on NETIF_F_HIGHDMA line. * fixed the issue reported by checkpatch: "Unnecessary parentheses around 'nt->encap.type == TUNNEL_ENCAP_NONE'"

Fixes: ac4eb009e477 ("ip6gre: Add support for basic offloads offloads excluding GSO") Signed-off-by: Alexey Kodanev alexey.kodanev@oracle.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ip6_gre.c | 57 +++++++++++++++++++++++++++++------------------------ 1 file changed, 32 insertions(+), 25 deletions(-)

--- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1020,6 +1020,36 @@ static void ip6gre_tunnel_setup(struct n eth_random_addr(dev->perm_addr); }

+#define GRE6_FEATURES (NETIF_F_SG | \ + NETIF_F_FRAGLIST | \ + NETIF_F_HIGHDMA | \ + NETIF_F_HW_CSUM) + +static void ip6gre_tnl_init_features(struct net_device *dev) +{ + struct ip6_tnl *nt = netdev_priv(dev); + + dev->features |= GRE6_FEATURES; + dev->hw_features |= GRE6_FEATURES; + + if (!(nt->parms.o_flags & TUNNEL_SEQ)) { + /* TCP offload with GRE SEQ is not supported, nor + * can we support 2 levels of outer headers requiring + * an update. + */ + if (!(nt->parms.o_flags & TUNNEL_CSUM) || + nt->encap.type == TUNNEL_ENCAP_NONE) { + dev->features |= NETIF_F_GSO_SOFTWARE; + dev->hw_features |= NETIF_F_GSO_SOFTWARE; + } + + /* Can use a lockless transmit, unless we generate + * output sequences + */ + dev->features |= NETIF_F_LLTX; + } +} + static int ip6gre_tunnel_init_common(struct net_device *dev) { struct ip6_tnl *tunnel; @@ -1054,6 +1084,8 @@ static int ip6gre_tunnel_init_common(str if (!(tunnel->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) dev->mtu -= 8;

+ ip6gre_tnl_init_features(dev); + return 0; }

@@ -1302,11 +1334,6 @@ static const struct net_device_ops ip6gr .ndo_get_iflink = ip6_tnl_get_iflink, };

-#define GRE6_FEATURES (NETIF_F_SG | \ - NETIF_F_FRAGLIST | \ - NETIF_F_HIGHDMA | \ - NETIF_F_HW_CSUM) - static void ip6gre_tap_setup(struct net_device *dev) {

@@ -1386,26 +1413,6 @@ static int ip6gre_newlink(struct net *sr nt->net = dev_net(dev); ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);

- dev->features |= GRE6_FEATURES; - dev->hw_features |= GRE6_FEATURES; - - if (!(nt->parms.o_flags & TUNNEL_SEQ)) { - /* TCP offload with GRE SEQ is not supported, nor - * can we support 2 levels of outer headers requiring - * an update. - */ - if (!(nt->parms.o_flags & TUNNEL_CSUM) || - (nt->encap.type == TUNNEL_ENCAP_NONE)) { - dev->features |= NETIF_F_GSO_SOFTWARE; - dev->hw_features |= NETIF_F_GSO_SOFTWARE; - } - - /* Can use a lockless transmit, unless we generate - * output sequences - */ - dev->features |= NETIF_F_LLTX; - } - err = register_netdevice(dev); if (err) goto out;

Patches currently in stable-queue which might be from alexey.kodanev@oracle.com are

queue-4.14/vxlan-restore-dev-mtu-setting-based-on-lower-device.patch queue-4.14/ip6_gre-fix-device-features-for-ioctl-setup.patch