Re: [PATCH net] virtio-net: restore VIRTIO_HDR_F_DATA_VALID on receiving

From: Rolf Neugebauer
Date: Fri Jan 20 2017 - 05:56:42 EST


On Fri, Jan 20, 2017 at 6:32 AM, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> Commit 501db511397f ("virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on
> xmit") in fact disables VIRTIO_HDR_F_DATA_VALID on receiving path too,
> fixing this by adding a hint (has_data_valid) and set it only on the
> receiving path.
>
> Cc: Rolf Neugebauer <rolf.neugebauer@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>

Acked-by: Rolf Neugebauer <rolf.neugebauer@xxxxxxxxxx>

Ah, I missed this use of the function. Looks like this patch does not
regress the issue I was seeing with virtio_net.

Rolf

> ---
> drivers/net/macvtap.c | 2 +-
> drivers/net/tun.c | 2 +-
> drivers/net/virtio_net.c | 2 +-
> include/linux/virtio_net.h | 6 +++++-
> net/packet/af_packet.c | 4 ++--
> 5 files changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index 5c26653..4026185 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -825,7 +825,7 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
> return -EINVAL;
>
> if (virtio_net_hdr_from_skb(skb, &vnet_hdr,
> - macvtap_is_little_endian(q)))
> + macvtap_is_little_endian(q), true))
> BUG();
>
> if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index cd8e02c..2cd10b2 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1360,7 +1360,7 @@ static ssize_t tun_put_user(struct tun_struct *tun,
> return -EINVAL;
>
> if (virtio_net_hdr_from_skb(skb, &gso,
> - tun_is_little_endian(tun))) {
> + tun_is_little_endian(tun), true)) {
> struct skb_shared_info *sinfo = skb_shinfo(skb);
> pr_err("unexpected GSO type: "
> "0x%x, gso_size %d, hdr_len %d\n",
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 4a10500..3474243 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1104,7 +1104,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
> hdr = skb_vnet_hdr(skb);
>
> if (virtio_net_hdr_from_skb(skb, &hdr->hdr,
> - virtio_is_little_endian(vi->vdev)))
> + virtio_is_little_endian(vi->vdev), false))
> BUG();
>
> if (vi->mergeable_rx_bufs)
> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
> index 5643647..5209b5e 100644
> --- a/include/linux/virtio_net.h
> +++ b/include/linux/virtio_net.h
> @@ -56,7 +56,8 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
>
> static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
> struct virtio_net_hdr *hdr,
> - bool little_endian)
> + bool little_endian,
> + bool has_data_valid)
> {
> memset(hdr, 0, sizeof(*hdr)); /* no info leak */
>
> @@ -91,6 +92,9 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
> skb_checksum_start_offset(skb));
> hdr->csum_offset = __cpu_to_virtio16(little_endian,
> skb->csum_offset);
> + } else if (has_data_valid &&
> + skb->ip_summed == CHECKSUM_UNNECESSARY) {
> + hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
> } /* else everything is zero */
>
> return 0;
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index b9e1a13..3d555c7 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -1976,7 +1976,7 @@ static int packet_rcv_vnet(struct msghdr *msg, const struct sk_buff *skb,
> return -EINVAL;
> *len -= sizeof(vnet_hdr);
>
> - if (virtio_net_hdr_from_skb(skb, &vnet_hdr, vio_le()))
> + if (virtio_net_hdr_from_skb(skb, &vnet_hdr, vio_le(), true))
> return -EINVAL;
>
> return memcpy_to_msg(msg, (void *)&vnet_hdr, sizeof(vnet_hdr));
> @@ -2237,7 +2237,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
> if (po->has_vnet_hdr) {
> if (virtio_net_hdr_from_skb(skb, h.raw + macoff -
> sizeof(struct virtio_net_hdr),
> - vio_le())) {
> + vio_le(), true)) {
> spin_lock(&sk->sk_receive_queue.lock);
> goto drop_n_account;
> }
> --
> 2.7.4
>