ip6_gre: fix device features for ioctl setup

[ 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>

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 5d6bee070871f1f5b8468ea75cdf406de4dfe035..7a2df6646486ae6bf308aca17bfaf296c36f2227 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1020,6 +1020,36 @@ static void ip6gre_tunnel_setup(struct net_device *dev)
        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(struct net_device *dev)
        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 ip6gre_tap_netdev_ops = {
        .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 *src_net, struct net_device *dev,
        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;