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virtio-net: support multi-buffer xdp

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Driver can pass the skb to stack by build_skb_from_xdp_buff().

Driver forwards multi-buffer packets using the send queue
when XDP_TX and XDP_REDIRECT, and clears the reference of multi
pages when XDP_DROP.

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 16:22:29 +08:00 committed by David S. Miller
parent 18117a842a
commit fab89bafa9
1 changed files with 10 additions and 55 deletions
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63
drivers/net/virtio_net.c
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@ -1090,7 +1090,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
struct bpf_prog *xdp_prog;
unsigned int truesize = mergeable_ctx_to_truesize(ctx);
unsigned int headroom = mergeable_ctx_to_headroom(ctx);
unsigned int metasize = 0;
unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
unsigned int frame_sz, xdp_room;
@ -1186,63 +1185,24 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
switch (act) {
case XDP_PASS:
metasize = xdp.data - xdp.data_meta;
/* recalculate offset to account for any header
* adjustments and minus the metasize to copy the
* metadata in page_to_skb(). Note other cases do not
* build an skb and avoid using offset
*/
offset = xdp.data - page_address(xdp_page) -
vi->hdr_len - metasize;
/* recalculate len if xdp.data, xdp.data_end or
* xdp.data_meta were adjusted
*/
len = xdp.data_end - xdp.data + vi->hdr_len + metasize;
/* recalculate headroom if xdp.data or xdp_data_meta
* were adjusted, note that offset should always point
* to the start of the reserved bytes for virtio_net
* header which are followed by xdp.data, that means
* that offset is equal to the headroom (when buf is
* starting at the beginning of the page, otherwise
* there is a base offset inside the page) but it's used
* with a different starting point (buf start) than
* xdp.data (buf start + vnet hdr size). If xdp.data or
* data_meta were adjusted by the xdp prog then the
* headroom size has changed and so has the offset, we
* can use data_hard_start, which points at buf start +
* vnet hdr size, to calculate the new headroom and use
* it later to compute buf start in page_to_skb()
*/
headroom = xdp.data - xdp.data_hard_start - metasize;
/* We can only create skb based on xdp_page. */
if (unlikely(xdp_page != page)) {
rcu_read_unlock();
if (unlikely(xdp_page != page))
put_page(page);
head_skb = page_to_skb(vi, rq, xdp_page, offset,
len, PAGE_SIZE);
head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
rcu_read_unlock();
return head_skb;
}
break;
case XDP_TX:
stats->xdp_tx++;
xdpf = xdp_convert_buff_to_frame(&xdp);
if (unlikely(!xdpf)) {
if (unlikely(xdp_page != page))
put_page(xdp_page);
goto err_xdp;
netdev_dbg(dev, "convert buff to frame failed for xdp\n");
goto err_xdp_frags;
}
err = virtnet_xdp_xmit(dev, 1, &xdpf, 0);
if (unlikely(!err)) {
xdp_return_frame_rx_napi(xdpf);
} else if (unlikely(err < 0)) {
trace_xdp_exception(vi->dev, xdp_prog, act);
if (unlikely(xdp_page != page))
put_page(xdp_page);
goto err_xdp;
goto err_xdp_frags;
}
*xdp_xmit |= VIRTIO_XDP_TX;
if (unlikely(xdp_page != page))
@ -1252,11 +1212,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
case XDP_REDIRECT:
stats->xdp_redirects++;
err = xdp_do_redirect(dev, &xdp, xdp_prog);
if (err) {
if (unlikely(xdp_page != page))
put_page(xdp_page);
goto err_xdp;
}
if (err)
goto err_xdp_frags;
*xdp_xmit |= VIRTIO_XDP_REDIR;
if (unlikely(xdp_page != page))
put_page(page);
@ -1269,9 +1226,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
trace_xdp_exception(vi->dev, xdp_prog, act);
fallthrough;
case XDP_DROP:
if (unlikely(xdp_page != page))
__free_pages(xdp_page, 0);
goto err_xdp;
goto err_xdp_frags;
}
err_xdp_frags:
if (unlikely(xdp_page != page))