From: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
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.
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.toshi...@lab.ntt.co.jp>
---
drivers/net/veth.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 110 insertions(+), 9 deletions(-)
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index acdb1c543f4b..60397a8ea2e9 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -32,6 +32,10 @@
#define VETH_RING_SIZE 256
#define VETH_XDP_HEADROOM (XDP_PACKET_HEADROOM + NET_IP_ALIGN)
+/* Separating two types of XDP xmit */
+#define VETH_XDP_TX BIT(0)
+#define VETH_XDP_REDIR BIT(1)
+
struct pcpu_vstats {
u64 packets;
u64 bytes;
@@ -45,6 +49,7 @@ struct veth_priv {
struct bpf_prog *_xdp_prog;
struct net_device __rcu *peer;
atomic64_t dropped;
+ struct xdp_mem_info xdp_mem;
unsigned requested_headroom;
bool rx_notify_masked;
struct ptr_ring xdp_ring;
@@ -317,10 +322,42 @@ static int veth_xdp_xmit(struct net_device *dev, int n,
return n - drops;
}
+static void veth_xdp_flush(struct net_device *dev)
+{
+ struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
+ struct net_device *rcv;
+
+ rcu_read_lock();
+ rcv = rcu_dereference(priv->peer);
+ if (unlikely(!rcv))
+ goto out;
+
+ rcv_priv = netdev_priv(rcv);
+ /* xdp_ring is initialized on receive side? */
+ if (unlikely(!rcu_access_pointer(rcv_priv->xdp_prog)))
+ goto out;
+
+ __veth_xdp_flush(rcv_priv);
+out:
+ rcu_read_unlock();
+}
+
+static int veth_xdp_tx(struct net_device *dev, struct xdp_buff *xdp)
+{
+ struct xdp_frame *frame = convert_to_xdp_frame(xdp);
+
+ if (unlikely(!frame))
+ return -EOVERFLOW;
+
+ return veth_xdp_xmit(dev, 1, &frame, 0);
+}
+
static struct sk_buff *veth_xdp_rcv_one(struct veth_priv *priv,
- struct xdp_frame *frame)
+ struct xdp_frame *frame,
+ unsigned int *xdp_xmit)
{
int len = frame->len, delta = 0;
+ struct xdp_frame orig_frame;
struct bpf_prog *xdp_prog;
unsigned int headroom;
struct sk_buff *skb;
@@ -344,6 +381,29 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_priv
*priv,
delta = frame->data - xdp.data;
len = xdp.data_end - xdp.data;
break;
+ case XDP_TX:
+ orig_frame = *frame;
+ xdp.data_hard_start = frame;
+ xdp.rxq->mem = frame->mem;
+ if (unlikely(veth_xdp_tx(priv->dev, &xdp) < 0)) {
+ trace_xdp_exception(priv->dev, xdp_prog, act);
+ frame = &orig_frame;
+ goto err_xdp;
+ }
+ *xdp_xmit |= VETH_XDP_TX;
+ rcu_read_unlock();
+ goto xdp_xmit;
+ case XDP_REDIRECT:
+ orig_frame = *frame;
+ xdp.data_hard_start = frame;
+ xdp.rxq->mem = frame->mem;
+ if (xdp_do_redirect(priv->dev, &xdp, xdp_prog)) {
+ frame = &orig_frame;
+ goto err_xdp;
+ }
+ *xdp_xmit |= VETH_XDP_REDIR;
+ rcu_read_unlock();
+ goto xdp_xmit;
default:
bpf_warn_invalid_xdp_action(act);
case XDP_ABORTED:
@@ -368,12 +428,13 @@ static struct sk_buff *veth_xdp_rcv_one(struct veth_priv
*priv,
err_xdp:
rcu_read_unlock();
xdp_return_frame(frame);
-
+xdp_xmit:
return NULL;
}
static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv *priv,
- struct sk_buff *skb)
+ struct sk_buff *skb,
+ unsigned int *xdp_xmit)
{
u32 pktlen, headroom, act, metalen;
void *orig_data, *orig_data_end;
@@ -444,6 +505,26 @@ static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv
*priv,
switch (act) {
case XDP_PASS:
break;
+ case XDP_TX:
+ get_page(virt_to_page(xdp.data));
+ consume_skb(skb);
+ xdp.rxq->mem = priv->xdp_mem;
+ if (unlikely(veth_xdp_tx(priv->dev, &xdp) < 0)) {
+ trace_xdp_exception(priv->dev, xdp_prog, act);
+ goto err_xdp;
+ }
+ *xdp_xmit |= VETH_XDP_TX;
+ rcu_read_unlock();
+ goto xdp_xmit;
+ case XDP_REDIRECT:
+ get_page(virt_to_page(xdp.data));
+ consume_skb(skb);
+ xdp.rxq->mem = priv->xdp_mem;
+ if (xdp_do_redirect(priv->dev, &xdp, xdp_prog))
+ goto err_xdp;
+ *xdp_xmit |= VETH_XDP_REDIR;
+ rcu_read_unlock();
+ goto xdp_xmit;
default:
bpf_warn_invalid_xdp_action(act);
case XDP_ABORTED:
@@ -474,9 +555,15 @@ static struct sk_buff *veth_xdp_rcv_skb(struct veth_priv
*priv,
rcu_read_unlock();
kfree_skb(skb);
return NULL;
+err_xdp:
+ rcu_read_unlock();
+ page_frag_free(xdp.data);
+xdp_xmit:
+ return NULL;
}
-static int veth_xdp_rcv(struct veth_priv *priv, int budget)
+static int veth_xdp_rcv(struct veth_priv *priv, int budget,
+ unsigned int *xdp_xmit)
{
int i, done = 0;
@@ -487,10 +574,12 @@ static int veth_xdp_rcv(struct veth_priv *priv, int
budget)
if (!ptr)
break;
- if (veth_is_xdp_frame(ptr))
- skb = veth_xdp_rcv_one(priv, veth_ptr_to_xdp(ptr));
- else
- skb = veth_xdp_rcv_skb(priv, ptr);
+ if (veth_is_xdp_frame(ptr)) {
+ skb = veth_xdp_rcv_one(priv, veth_ptr_to_xdp(ptr),
+ xdp_xmit);
+ } else {
+ skb = veth_xdp_rcv_skb(priv, ptr, xdp_xmit);
+ }
if (skb)
napi_gro_receive(&priv->xdp_napi, skb);
@@ -505,9 +594,11 @@ static int veth_poll(struct napi_struct *napi, int budget)
{
struct veth_priv *priv =
container_of(napi, struct veth_priv, xdp_napi);
+ unsigned int xdp_xmit = 0;
int done;
- done = veth_xdp_rcv(priv, budget);
+ xdp_set_return_frame_no_direct();
+ done = veth_xdp_rcv(priv, budget, &xdp_xmit);
if (done < budget && napi_complete_done(napi, done)) {
/* Write rx_notify_masked before reading ptr_ring */
@@ -518,6 +609,12 @@ static int veth_poll(struct napi_struct *napi, int budget)
}
}
+ if (xdp_xmit & VETH_XDP_TX)
+ veth_xdp_flush(priv->dev);
+ if (xdp_xmit & VETH_XDP_REDIR)
+ xdp_do_flush_map();
+ xdp_clear_return_frame_no_direct();
+
return done;
}
@@ -564,6 +661,9 @@ static int veth_enable_xdp(struct net_device *dev)
err = veth_napi_add(dev);
if (err)
goto err;
+
+ /* Save original mem info as it can be overwritten */
+ priv->xdp_mem = priv->xdp_rxq.mem;
}
rcu_assign_pointer(priv->xdp_prog, priv->_xdp_prog);
@@ -581,6 +681,7 @@ static void veth_disable_xdp(struct net_device *dev)
rcu_assign_pointer(priv->xdp_prog, NULL);
veth_napi_del(dev);
+ priv->xdp_rxq.mem = priv->xdp_mem;
xdp_rxq_info_unreg(&priv->xdp_rxq);
}
--
2.14.3
