diff options
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/virtio_net.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 6d3cf8887dd7..5d3aad2ef8d0 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -959,6 +959,55 @@ err: return NULL; } +/* Why not use xdp_build_skb_from_frame() ? + * XDP core assumes that xdp frags are PAGE_SIZE in length, while in + * virtio-net there are 2 points that do not match its requirements: + * 1. The size of the prefilled buffer is not fixed before xdp is set. + * 2. xdp_build_skb_from_frame() does more checks that we don't need, + * like eth_type_trans() (which virtio-net does in receive_buf()). + */ +static struct sk_buff *build_skb_from_xdp_buff(struct net_device *dev, + struct virtnet_info *vi, + struct xdp_buff *xdp, + unsigned int xdp_frags_truesz) +{ + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); + unsigned int headroom, data_len; + struct sk_buff *skb; + int metasize; + u8 nr_frags; + + if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) { + pr_debug("Error building skb as missing reserved tailroom for xdp"); + return NULL; + } + + if (unlikely(xdp_buff_has_frags(xdp))) + nr_frags = sinfo->nr_frags; + + skb = build_skb(xdp->data_hard_start, xdp->frame_sz); + if (unlikely(!skb)) + return NULL; + + headroom = xdp->data - xdp->data_hard_start; + data_len = xdp->data_end - xdp->data; + skb_reserve(skb, headroom); + __skb_put(skb, data_len); + + metasize = xdp->data - xdp->data_meta; + metasize = metasize > 0 ? metasize : 0; + if (metasize) + skb_metadata_set(skb, metasize); + + if (unlikely(xdp_buff_has_frags(xdp))) + xdp_update_skb_shared_info(skb, nr_frags, + sinfo->xdp_frags_size, + xdp_frags_truesz, + xdp_buff_is_frag_pfmemalloc(xdp)); + + return skb; +} + /* TODO: build xdp in big mode */ static int virtnet_build_xdp_buff_mrg(struct net_device *dev, struct virtnet_info *vi, |