在 2023/1/3 下午2:40, Heng Qi 写道:
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;
Hi Jason, I've updated the calculation of 'max_sz' in this patch instead
of a separate bugfix, since doing so also seemed clear.
Thanks.
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;
}
