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virtio-net: build skb from multi-buffer xdp

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This converts the xdp_buff directly to a skb, including
multi-buffer and single buffer xdp. We'll isolate the
construction of skb based on xdp from page_to_skb().

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Heng Qi 2023-01-14 16:22:27 +08:00 committed by David S. Miller
parent 97717e8dbd
commit b26aa481b4
1 changed files with 49 additions and 0 deletions
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49
drivers/net/virtio_net.c
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@ -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,