Re: [PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[Jason Wang]

On 2017年09月21日 06:02, John Fastabend wrote:

On 09/19/2017 02:42 AM, Jason Wang wrote:

This patch tries to add XDP_REDIRECT for virtio-net. The changes are
not complex as we could use exist XDP_TX helpers for most of the
work. The rest is passing the XDP_TX to NAPI handler for implementing
batching.

Cc: John Fastabend 
Signed-off-by: Jason Wang 
---

[...]


@@ -678,12 +711,20 @@ static struct sk_buff *receive_mergeable(struct 
net_device *dev,
}
break;
case XDP_TX:
-   if (unlikely(!virtnet_xdp_xmit(vi, )))
+   if (unlikely(!__virtnet_xdp_xmit(vi, )))
trace_xdp_exception(vi->dev, xdp_prog, act);
+   else
+   *xdp_xmit = true;
if (unlikely(xdp_page != page))
goto err_xdp;
rcu_read_unlock();
goto xdp_xmit;
+   case XDP_REDIRECT:
+   err = xdp_do_redirect(dev, , xdp_prog);
+   if (err)
+   *xdp_xmit = true;

Is this a typo? Should above be

if (!err)
*xdp_xmit = true;

this would match the pattern in receive_small and also make more sense.


Right, will post a fix.




+   rcu_read_unlock();
+   goto xdp_xmit;
default:
bpf_warn_invalid_xdp_action(act);
case XDP_ABORTED:
@@ -788,7 +829,7 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
  }
  

[...]

Otherwise looks good to me thanks for doing this.

.John



Thanks for the reviewing.

Re: [PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[Jason Wang]

On 2017年09月21日 06:02, John Fastabend wrote:

On 09/19/2017 02:42 AM, Jason Wang wrote:

This patch tries to add XDP_REDIRECT for virtio-net. The changes are
not complex as we could use exist XDP_TX helpers for most of the
work. The rest is passing the XDP_TX to NAPI handler for implementing
batching.

Cc: John Fastabend 
Signed-off-by: Jason Wang 
---

[...]


@@ -678,12 +711,20 @@ static struct sk_buff *receive_mergeable(struct 
net_device *dev,
}
break;
case XDP_TX:
-   if (unlikely(!virtnet_xdp_xmit(vi, )))
+   if (unlikely(!__virtnet_xdp_xmit(vi, )))
trace_xdp_exception(vi->dev, xdp_prog, act);
+   else
+   *xdp_xmit = true;
if (unlikely(xdp_page != page))
goto err_xdp;
rcu_read_unlock();
goto xdp_xmit;
+   case XDP_REDIRECT:
+   err = xdp_do_redirect(dev, , xdp_prog);
+   if (err)
+   *xdp_xmit = true;

Is this a typo? Should above be

if (!err)
*xdp_xmit = true;

this would match the pattern in receive_small and also make more sense.


Right, will post a fix.




+   rcu_read_unlock();
+   goto xdp_xmit;
default:
bpf_warn_invalid_xdp_action(act);
case XDP_ABORTED:
@@ -788,7 +829,7 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
  }
  

[...]

Otherwise looks good to me thanks for doing this.

.John



Thanks for the reviewing.

Re: [PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[John Fastabend]

On 09/19/2017 02:42 AM, Jason Wang wrote:
> This patch tries to add XDP_REDIRECT for virtio-net. The changes are
> not complex as we could use exist XDP_TX helpers for most of the
> work. The rest is passing the XDP_TX to NAPI handler for implementing
> batching.
> 
> Cc: John Fastabend 
> Signed-off-by: Jason Wang 
> ---

[...]

> @@ -678,12 +711,20 @@ static struct sk_buff *receive_mergeable(struct 
> net_device *dev,
>   }
>   break;
>   case XDP_TX:
> - if (unlikely(!virtnet_xdp_xmit(vi, )))
> + if (unlikely(!__virtnet_xdp_xmit(vi, )))
>   trace_xdp_exception(vi->dev, xdp_prog, act);
> + else
> + *xdp_xmit = true;
>   if (unlikely(xdp_page != page))
>   goto err_xdp;
>   rcu_read_unlock();
>   goto xdp_xmit;
> + case XDP_REDIRECT:
> + err = xdp_do_redirect(dev, , xdp_prog);
> + if (err)
> + *xdp_xmit = true;

Is this a typo? Should above be

if (!err)
*xdp_xmit = true;

this would match the pattern in receive_small and also make more sense.

> + rcu_read_unlock();
> + goto xdp_xmit;
>   default:
>   bpf_warn_invalid_xdp_action(act);
>   case XDP_ABORTED:
> @@ -788,7 +829,7 @@ static struct sk_buff *receive_mergeable(struct 
> net_device *dev,
>  }
>  

[...]

Otherwise looks good to me thanks for doing this.

.John

Re: [PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[John Fastabend]

On 09/19/2017 02:42 AM, Jason Wang wrote:
> This patch tries to add XDP_REDIRECT for virtio-net. The changes are
> not complex as we could use exist XDP_TX helpers for most of the
> work. The rest is passing the XDP_TX to NAPI handler for implementing
> batching.
> 
> Cc: John Fastabend 
> Signed-off-by: Jason Wang 
> ---

[...]

> @@ -678,12 +711,20 @@ static struct sk_buff *receive_mergeable(struct 
> net_device *dev,
>   }
>   break;
>   case XDP_TX:
> - if (unlikely(!virtnet_xdp_xmit(vi, )))
> + if (unlikely(!__virtnet_xdp_xmit(vi, )))
>   trace_xdp_exception(vi->dev, xdp_prog, act);
> + else
> + *xdp_xmit = true;
>   if (unlikely(xdp_page != page))
>   goto err_xdp;
>   rcu_read_unlock();
>   goto xdp_xmit;
> + case XDP_REDIRECT:
> + err = xdp_do_redirect(dev, , xdp_prog);
> + if (err)
> + *xdp_xmit = true;

Is this a typo? Should above be

if (!err)
*xdp_xmit = true;

this would match the pattern in receive_small and also make more sense.

> + rcu_read_unlock();
> + goto xdp_xmit;
>   default:
>   bpf_warn_invalid_xdp_action(act);
>   case XDP_ABORTED:
> @@ -788,7 +829,7 @@ static struct sk_buff *receive_mergeable(struct 
> net_device *dev,
>  }
>  

[...]

Otherwise looks good to me thanks for doing this.

.John

Re: [PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[David Miller]

From: Jason Wang 
Date: Tue, 19 Sep 2017 17:42:43 +0800

> This patch tries to add XDP_REDIRECT for virtio-net. The changes are
> not complex as we could use exist XDP_TX helpers for most of the
> work. The rest is passing the XDP_TX to NAPI handler for implementing
> batching.
> 
> Cc: John Fastabend 
> Signed-off-by: Jason Wang 

Applied.

Re: [PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[David Miller]

From: Jason Wang 
Date: Tue, 19 Sep 2017 17:42:43 +0800

> This patch tries to add XDP_REDIRECT for virtio-net. The changes are
> not complex as we could use exist XDP_TX helpers for most of the
> work. The rest is passing the XDP_TX to NAPI handler for implementing
> batching.
> 
> Cc: John Fastabend 
> Signed-off-by: Jason Wang 

Applied.

[PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[Jason Wang]

This patch tries to add XDP_REDIRECT for virtio-net. The changes are
not complex as we could use exist XDP_TX helpers for most of the
work. The rest is passing the XDP_TX to NAPI handler for implementing
batching.

Cc: John Fastabend 
Signed-off-by: Jason Wang 
---
 drivers/net/virtio_net.  |  0
 drivers/net/virtio_net.c | 77 ++--
 2 files changed, 62 insertions(+), 15 deletions(-)
 create mode 100644 drivers/net/virtio_net.

diff --git a/drivers/net/virtio_net. b/drivers/net/virtio_net.
new file mode 100644
index 000..e69de29
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index db5924c..f6c1f13 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -29,6 +29,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 static int napi_weight = NAPI_POLL_WEIGHT;
@@ -372,8 +373,20 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
return skb;
 }
 
-static bool virtnet_xdp_xmit(struct virtnet_info *vi,
-struct xdp_buff *xdp)
+static void virtnet_xdp_flush(struct net_device *dev)
+{
+   struct virtnet_info *vi = netdev_priv(dev);
+   struct send_queue *sq;
+   unsigned int qp;
+
+   qp = vi->curr_queue_pairs - vi->xdp_queue_pairs + smp_processor_id();
+   sq = >sq[qp];
+
+   virtqueue_kick(sq->vq);
+}
+
+static bool __virtnet_xdp_xmit(struct virtnet_info *vi,
+  struct xdp_buff *xdp)
 {
struct virtio_net_hdr_mrg_rxbuf *hdr;
unsigned int len;
@@ -407,10 +420,19 @@ static bool virtnet_xdp_xmit(struct virtnet_info *vi,
return false;
}
 
-   virtqueue_kick(sq->vq);
return true;
 }
 
+static int virtnet_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
+{
+   struct virtnet_info *vi = netdev_priv(dev);
+   bool sent = __virtnet_xdp_xmit(vi, xdp);
+
+   if (!sent)
+   return -ENOSPC;
+   return 0;
+}
+
 static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
 {
return vi->xdp_queue_pairs ? VIRTIO_XDP_HEADROOM : 0;
@@ -483,7 +505,8 @@ static struct sk_buff *receive_small(struct net_device *dev,
 struct virtnet_info *vi,
 struct receive_queue *rq,
 void *buf, void *ctx,
-unsigned int len)
+unsigned int len,
+bool *xdp_xmit)
 {
struct sk_buff *skb;
struct bpf_prog *xdp_prog;
@@ -493,7 +516,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
unsigned int buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
  SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
struct page *page = virt_to_head_page(buf);
-   unsigned int delta = 0;
+   unsigned int delta = 0, err;
struct page *xdp_page;
len -= vi->hdr_len;
 
@@ -541,8 +564,16 @@ static struct sk_buff *receive_small(struct net_device 
*dev,
delta = orig_data - xdp.data;
break;
case XDP_TX:
-   if (unlikely(!virtnet_xdp_xmit(vi, )))
+   if (unlikely(!__virtnet_xdp_xmit(vi, )))
trace_xdp_exception(vi->dev, xdp_prog, act);
+   else
+   *xdp_xmit = true;
+   rcu_read_unlock();
+   goto xdp_xmit;
+   case XDP_REDIRECT:
+   err = xdp_do_redirect(dev, , xdp_prog);
+   if (!err)
+   *xdp_xmit = true;
rcu_read_unlock();
goto xdp_xmit;
default:
@@ -603,7 +634,8 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
 struct receive_queue *rq,
 void *buf,
 void *ctx,
-unsigned int len)
+unsigned int len,
+bool *xdp_xmit)
 {
struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
@@ -613,6 +645,7 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
struct bpf_prog *xdp_prog;
unsigned int truesize;
unsigned int headroom = mergeable_ctx_to_headroom(ctx);
+   int err;
 
head_skb = NULL;
 
@@ -678,12 +711,20 @@ static struct sk_buff *receive_mergeable(struct 
net_device *dev,
}
break;
case XDP_TX:
-   if (unlikely(!virtnet_xdp_xmit(vi, )))
+  

[PATCH net-next 3/3] virtio-net: support XDP_REDIRECT

[Jason Wang]

This patch tries to add XDP_REDIRECT for virtio-net. The changes are
not complex as we could use exist XDP_TX helpers for most of the
work. The rest is passing the XDP_TX to NAPI handler for implementing
batching.

Cc: John Fastabend 
Signed-off-by: Jason Wang 
---
 drivers/net/virtio_net.  |  0
 drivers/net/virtio_net.c | 77 ++--
 2 files changed, 62 insertions(+), 15 deletions(-)
 create mode 100644 drivers/net/virtio_net.

diff --git a/drivers/net/virtio_net. b/drivers/net/virtio_net.
new file mode 100644
index 000..e69de29
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index db5924c..f6c1f13 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -29,6 +29,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 static int napi_weight = NAPI_POLL_WEIGHT;
@@ -372,8 +373,20 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
return skb;
 }
 
-static bool virtnet_xdp_xmit(struct virtnet_info *vi,
-struct xdp_buff *xdp)
+static void virtnet_xdp_flush(struct net_device *dev)
+{
+   struct virtnet_info *vi = netdev_priv(dev);
+   struct send_queue *sq;
+   unsigned int qp;
+
+   qp = vi->curr_queue_pairs - vi->xdp_queue_pairs + smp_processor_id();
+   sq = >sq[qp];
+
+   virtqueue_kick(sq->vq);
+}
+
+static bool __virtnet_xdp_xmit(struct virtnet_info *vi,
+  struct xdp_buff *xdp)
 {
struct virtio_net_hdr_mrg_rxbuf *hdr;
unsigned int len;
@@ -407,10 +420,19 @@ static bool virtnet_xdp_xmit(struct virtnet_info *vi,
return false;
}
 
-   virtqueue_kick(sq->vq);
return true;
 }
 
+static int virtnet_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp)
+{
+   struct virtnet_info *vi = netdev_priv(dev);
+   bool sent = __virtnet_xdp_xmit(vi, xdp);
+
+   if (!sent)
+   return -ENOSPC;
+   return 0;
+}
+
 static unsigned int virtnet_get_headroom(struct virtnet_info *vi)
 {
return vi->xdp_queue_pairs ? VIRTIO_XDP_HEADROOM : 0;
@@ -483,7 +505,8 @@ static struct sk_buff *receive_small(struct net_device *dev,
 struct virtnet_info *vi,
 struct receive_queue *rq,
 void *buf, void *ctx,
-unsigned int len)
+unsigned int len,
+bool *xdp_xmit)
 {
struct sk_buff *skb;
struct bpf_prog *xdp_prog;
@@ -493,7 +516,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
unsigned int buflen = SKB_DATA_ALIGN(GOOD_PACKET_LEN + headroom) +
  SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
struct page *page = virt_to_head_page(buf);
-   unsigned int delta = 0;
+   unsigned int delta = 0, err;
struct page *xdp_page;
len -= vi->hdr_len;
 
@@ -541,8 +564,16 @@ static struct sk_buff *receive_small(struct net_device 
*dev,
delta = orig_data - xdp.data;
break;
case XDP_TX:
-   if (unlikely(!virtnet_xdp_xmit(vi, )))
+   if (unlikely(!__virtnet_xdp_xmit(vi, )))
trace_xdp_exception(vi->dev, xdp_prog, act);
+   else
+   *xdp_xmit = true;
+   rcu_read_unlock();
+   goto xdp_xmit;
+   case XDP_REDIRECT:
+   err = xdp_do_redirect(dev, , xdp_prog);
+   if (!err)
+   *xdp_xmit = true;
rcu_read_unlock();
goto xdp_xmit;
default:
@@ -603,7 +634,8 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
 struct receive_queue *rq,
 void *buf,
 void *ctx,
-unsigned int len)
+unsigned int len,
+bool *xdp_xmit)
 {
struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
@@ -613,6 +645,7 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
struct bpf_prog *xdp_prog;
unsigned int truesize;
unsigned int headroom = mergeable_ctx_to_headroom(ctx);
+   int err;
 
head_skb = NULL;
 
@@ -678,12 +711,20 @@ static struct sk_buff *receive_mergeable(struct 
net_device *dev,
}
break;
case XDP_TX:
-   if (unlikely(!virtnet_xdp_xmit(vi, )))
+   if