When the xdp program sets xdp.frags, which means it can process multi-buffer packets over larger MTU, so we continue to support xdp. But for single-buffer xdp, we should keep checking for MTU. Signed-off-by: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx> Reviewed-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> --- drivers/net/virtio_net.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 443aa7b8f0ad..60e199811212 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3074,7 +3074,9 @@ static int virtnet_restore_guest_offloads(struct virtnet_info *vi) static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog, struct netlink_ext_ack *extack) { - unsigned long int max_sz = PAGE_SIZE - sizeof(struct padded_vnet_hdr); + unsigned int room = SKB_DATA_ALIGN(VIRTIO_XDP_HEADROOM + + sizeof(struct skb_shared_info)); + unsigned int max_sz = PAGE_SIZE - room - ETH_HLEN; struct virtnet_info *vi = netdev_priv(dev); struct bpf_prog *old_prog; u16 xdp_qp = 0, curr_qp; @@ -3095,9 +3097,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog, return -EINVAL; } - if (dev->mtu > max_sz) { - NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP"); - netdev_warn(dev, "XDP requires MTU less than %lu\n", max_sz); + if (prog && !prog->aux->xdp_has_frags && dev->mtu > max_sz) { + NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP without frags"); + netdev_warn(dev, "single-buffer XDP requires MTU less than %u\n", max_sz); return -EINVAL; } -- 2.19.1.6.gb485710b