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veth: Add XDP TX and REDIRECT
This allows further redirection of xdp_frames like NIC -> veth--veth -> veth--veth (XDP) (XDP) (XDP) The intermediate XDP, redirecting packets from NIC to the other veth, reuses xdp_mem_info from NIC so that page recycling of the NIC works on the destination veth's XDP. In this way return_frame is not fully guarded by NAPI, since another NAPI handler on another cpu may use the same xdp_mem_info concurrently. Thus disable napi_direct by xdp_set_return_frame_no_direct() during the NAPI context. v8: - Don't use xdp_frame pointer address for data_hard_start of xdp_buff. v4: - Use xdp_[set|clear]_return_frame_no_direct() instead of a flag in xdp_mem_info. v3: - Fix double free when veth_xdp_tx() returns a positive value. - Convert xdp_xmit and xdp_redir variables into flags. Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Toshiaki Makita
Daniel Borkmann
parent
2539650fad
commit
d1396004dd
@ -32,6 +32,10 @@
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#define VETH_RING_SIZE 256
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#define VETH_XDP_HEADROOM (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
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/* Separating two types of XDP xmit */
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#define VETH_XDP_TX BIT(0)
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#define VETH_XDP_REDIR BIT(1)
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struct pcpu_vstats {
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u64 packets;
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u64 bytes;
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@ -45,6 +49,7 @@ struct veth_priv {
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struct bpf_prog *_xdp_prog;
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struct net_device __rcu *peer;
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atomic64_t dropped;
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struct xdp_mem_info xdp_mem;
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unsigned requested_headroom;
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bool rx_notify_masked;
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struct ptr_ring xdp_ring;
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@ -317,12 +322,44 @@ static int veth_xdp_xmit(struct net_device *dev, int n,
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return n - drops;
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}
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static void veth_xdp_flush(struct net_device *dev)
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{
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struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
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struct net_device *rcv;
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rcu_read_lock();
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rcv = rcu_dereference(priv->peer);
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if (unlikely(!rcv))
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goto out;
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rcv_priv = netdev_priv(rcv);
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/* xdp_ring is initialized on receive side? */
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if (unlikely(!rcu_access_pointer(rcv_priv->xdp_prog)))
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goto out;
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__veth_xdp_flush(rcv_priv);
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out:
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rcu_read_unlock();
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}
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static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
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{
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struct xdp_frame *frame = convert_to_xdp_frame(xdp);
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if (unlikely(!frame))
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return -EOVERFLOW;
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return veth_xdp_xmit(dev, 1, &frame, 0);
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}
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static struct sk_buff *veth_xdp_rcv_one(struct veth_priv *priv,
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struct xdp_frame *frame)
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struct xdp_frame *frame,
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unsigned int *xdp_xmit)
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{
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void *hard_start = frame->data - frame->headroom;
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void *head = hard_start - sizeof(struct xdp_frame);
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int len = frame->len, delta = 0;
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struct xdp_frame orig_frame;
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struct bpf_prog *xdp_prog;
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unsigned int headroom;
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struct sk_buff *skb;
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@ -346,6 +383,29 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_priv *priv,
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delta = frame->data - xdp.data;
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len = xdp.data_end - xdp.data;
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break;
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case XDP_TX:
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orig_frame = *frame;
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xdp.data_hard_start = head;
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xdp.rxq->mem = frame->mem;
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if (unlikely(veth_xdp_tx(priv->dev, &xdp) < 0)) {
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trace_xdp_exception(priv->dev, xdp_prog, act);
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frame = &orig_frame;
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goto err_xdp;
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}
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*xdp_xmit |= VETH_XDP_TX;
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rcu_read_unlock();
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goto xdp_xmit;
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case XDP_REDIRECT:
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orig_frame = *frame;
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xdp.data_hard_start = head;
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xdp.rxq->mem = frame->mem;
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if (xdp_do_redirect(priv->dev, &xdp, xdp_prog)) {
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frame = &orig_frame;
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goto err_xdp;
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}
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*xdp_xmit |= VETH_XDP_REDIR;
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rcu_read_unlock();
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goto xdp_xmit;
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default:
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bpf_warn_invalid_xdp_action(act);
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case XDP_ABORTED:
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@ -370,12 +430,13 @@ err:
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err_xdp:
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rcu_read_unlock();
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xdp_return_frame(frame);
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xdp_xmit:
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return NULL;
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}
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static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv *priv,
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struct sk_buff *skb)
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struct sk_buff *skb,
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unsigned int *xdp_xmit)
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{
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u32 pktlen, headroom, act, metalen;
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void *orig_data, *orig_data_end;
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@ -447,6 +508,26 @@ static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv *priv,
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switch (act) {
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case XDP_PASS:
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break;
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case XDP_TX:
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get_page(virt_to_page(xdp.data));
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consume_skb(skb);
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xdp.rxq->mem = priv->xdp_mem;
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if (unlikely(veth_xdp_tx(priv->dev, &xdp) < 0)) {
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trace_xdp_exception(priv->dev, xdp_prog, act);
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goto err_xdp;
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}
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*xdp_xmit |= VETH_XDP_TX;
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rcu_read_unlock();
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goto xdp_xmit;
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case XDP_REDIRECT:
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get_page(virt_to_page(xdp.data));
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consume_skb(skb);
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xdp.rxq->mem = priv->xdp_mem;
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if (xdp_do_redirect(priv->dev, &xdp, xdp_prog))
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goto err_xdp;
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*xdp_xmit |= VETH_XDP_REDIR;
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rcu_read_unlock();
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goto xdp_xmit;
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default:
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bpf_warn_invalid_xdp_action(act);
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case XDP_ABORTED:
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@ -477,9 +558,15 @@ drop:
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rcu_read_unlock();
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kfree_skb(skb);
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return NULL;
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err_xdp:
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rcu_read_unlock();
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page_frag_free(xdp.data);
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xdp_xmit:
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return NULL;
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}
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static int veth_xdp_rcv(struct veth_priv *priv, int budget)
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static int veth_xdp_rcv(struct veth_priv *priv, int budget,
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unsigned int *xdp_xmit)
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{
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int i, done = 0;
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@ -490,10 +577,12 @@ static int veth_xdp_rcv(struct veth_priv *priv, int budget)
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if (!ptr)
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break;
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if (veth_is_xdp_frame(ptr))
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skb = veth_xdp_rcv_one(priv, veth_ptr_to_xdp(ptr));
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else
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skb = veth_xdp_rcv_skb(priv, ptr);
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if (veth_is_xdp_frame(ptr)) {
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skb = veth_xdp_rcv_one(priv, veth_ptr_to_xdp(ptr),
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xdp_xmit);
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} else {
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skb = veth_xdp_rcv_skb(priv, ptr, xdp_xmit);
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}
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if (skb)
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napi_gro_receive(&priv->xdp_napi, skb);
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@ -508,9 +597,11 @@ static int veth_poll(struct napi_struct *napi, int budget)
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{
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struct veth_priv *priv =
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container_of(napi, struct veth_priv, xdp_napi);
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unsigned int xdp_xmit = 0;
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int done;
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done = veth_xdp_rcv(priv, budget);
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xdp_set_return_frame_no_direct();
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done = veth_xdp_rcv(priv, budget, &xdp_xmit);
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if (done < budget && napi_complete_done(napi, done)) {
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/* Write rx_notify_masked before reading ptr_ring */
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@ -521,6 +612,12 @@ static int veth_poll(struct napi_struct *napi, int budget)
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}
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}
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if (xdp_xmit & VETH_XDP_TX)
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veth_xdp_flush(priv->dev);
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if (xdp_xmit & VETH_XDP_REDIR)
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xdp_do_flush_map();
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xdp_clear_return_frame_no_direct();
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return done;
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}
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@ -567,6 +664,9 @@ static int veth_enable_xdp(struct net_device *dev)
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err = veth_napi_add(dev);
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if (err)
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goto err;
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/* Save original mem info as it can be overwritten */
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priv->xdp_mem = priv->xdp_rxq.mem;
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}
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rcu_assign_pointer(priv->xdp_prog, priv->_xdp_prog);
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@ -584,6 +684,7 @@ static void veth_disable_xdp(struct net_device *dev)
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rcu_assign_pointer(priv->xdp_prog, NULL);
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veth_napi_del(dev);
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priv->xdp_rxq.mem = priv->xdp_mem;
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xdp_rxq_info_unreg(&priv->xdp_rxq);
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}
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