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.koda...@oracle.com>
---
net/ipv6/ip6_gre.c | 57 +++++++++++++++++++++++++++++----------------------
1 files changed, 32 insertions(+), 25 deletions(-)
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 4cfd8e0..9a4b376 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1014,6 +1014,36 @@ 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;
@@ -1048,6 +1078,8 @@ 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;
}
@@ -1298,11 +1330,6 @@ static int ip6gre_tap_init(struct net_device *dev)
.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)
{
@@ -1382,26 +1409,6 @@ 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;
--
1.7.1
