2016-10-25 20:12:16

by Aaron Conole

Subject: [PATCH v2 net-next] virtio-net: Update the mtu code to match virtio spec

The virtio committee recently ratified a change, VIRTIO-152, which
defines the mtu field to be 'max' MTU, not simply desired MTU.

This commit brings the virtio-net device in compliance with VIRTIO-152.

Additionally, drop the max_mtu branch - it cannot be taken since the u16
returned by virtio_cread16 will never exceed the initial value of
max_mtu.

Signed-off-by: Aaron Conole <[email protected]>
Acked-by: "Michael S. Tsirkin" <[email protected]>
Acked-by: Jarod Wilson <[email protected]>
---
Nothing code-wise has changed, but I've included the ACKs and fixed up the
subject line.

drivers/net/virtio_net.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 720809f..2cafd12 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1870,10 +1870,12 @@ static int virtnet_probe(struct virtio_device *vdev)
mtu = virtio_cread16(vdev,
offsetof(struct virtio_net_config,
mtu));
- if (mtu < dev->min_mtu || mtu > dev->max_mtu)
+ if (mtu < dev->min_mtu) {
__virtio_clear_bit(vdev, VIRTIO_NET_F_MTU);
- else
+ } else {
dev->mtu = mtu;
+ dev->max_mtu = mtu;
+ }
}

if (vi->any_header_sg)
--
2.7.4

2016-10-29 16:01:05

by David Miller

Subject: Re: [PATCH v2 net-next] virtio-net: Update the mtu code to match virtio spec

From: Aaron Conole <[email protected]>
Date: Tue, 25 Oct 2016 16:12:12 -0400

> The virtio committee recently ratified a change, VIRTIO-152, which
> defines the mtu field to be 'max' MTU, not simply desired MTU.
>
> This commit brings the virtio-net device in compliance with VIRTIO-152.
>
> Additionally, drop the max_mtu branch - it cannot be taken since the u16
> returned by virtio_cread16 will never exceed the initial value of
> max_mtu.
>
> Signed-off-by: Aaron Conole <[email protected]>
> Acked-by: "Michael S. Tsirkin" <[email protected]>
> Acked-by: Jarod Wilson <[email protected]>
> ---
> Nothing code-wise has changed, but I've included the ACKs and fixed up the
> subject line.

Applied, thanks.