[Cake] Fwd: [PATCH net-next 2/2] veth: allow configuring GSO maximums

[Dave Taht]

veth might gain gso support.


---------- Forwarded message ----------
From: Stephen Hemminger <stephen at networkplumber.org>
Date: Fri, Dec 1, 2017 at 12:11 PM
Subject: [PATCH net-next 2/2] veth: allow configuring GSO maximums
To: davem at davemloft.net
Cc: netdev at vger.kernel.org, Stephen Hemminger <sthemmin at microsoft.com>


Veth's can be used in environments (like Azure) where the underlying
network device is impacted by large GSO packets. This patch allows
gso maximum values to be passed in when creating the device via
netlink.

In theory, other pseudo devices could also use netlink attributes
to set GSO maximums but for now veth is what has been observed
to be an issue.

Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
---
 drivers/net/veth.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index f5438d0978ca..510c058ba227 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -410,6 +410,26 @@ static int veth_newlink(struct net *src_net,
struct net_device *dev,
        if (ifmp && (dev->ifindex != 0))
                peer->ifindex = ifmp->ifi_index;

+       if (tbp[IFLA_GSO_MAX_SIZE]) {
+               u32 max_size = nla_get_u32(tbp[IFLA_GSO_MAX_SIZE]);
+
+               if (max_size > GSO_MAX_SIZE)
+                       return -EINVAL;
+
+               peer->gso_max_size = max_size;
+               dev->gso_max_size = max_size;
+       }
+
+       if (tbp[IFLA_GSO_MAX_SEGS]) {
+               u32 max_segs = nla_get_u32(tbp[IFLA_GSO_MAX_SEGS]);
+
+               if (max_segs > GSO_MAX_SEGS)
+                       return -EINVAL;
+
+               peer->gso_max_segs = max_segs;
+               dev->gso_max_segs = max_segs;
+       }
+
        err = register_netdevice(peer);
        put_net(net);
        net = NULL;
--
2.11.0



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619