在 2022/12/6 下午2:42, Jason Wang 写道:
On Tue, Nov 22, 2022 at 3:44 PM Heng Qi <hengqi@xxxxxxxxxxxxxxxxx> wrote: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@xxxxxxxxxxxxxxxxx> Reviewed-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> --- drivers/net/virtio_net.c | 65 ++++++---------------------------------- 1 file changed, 9 insertions(+), 56 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 431f2126a2b5..bbd5cd9bfd47 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1065,7 +1065,6 @@ 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 frame_sz; int err; @@ -1137,63 +1136,22 @@ 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(); - put_page(page); - head_skb = page_to_skb(vi, rq, xdp_page, offset, - len, PAGE_SIZE); - return head_skb; - } - break; + head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz); + rcu_read_unlock(); + return head_skb; 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; + pr_debug("%s: convert buff to frame failed for xdp\n", dev->name);netdev_dbg()?
Yes, I will fix it in the next version. Thanks.
Thanks+ 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)) @@ -1203,11 +1161,8 @@ 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); @@ -1220,9 +1175,7 @@ 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: shinfo = xdp_get_shared_info_from_buff(&xdp); -- 2.19.1.6.gb485710b
