Re: [net-next PATCH v2 2/5] virtio_net: factor out xdp handler for readability

[Jason Wang]

On 2017年02月03日 11:15, John Fastabend wrote:

At this point the do_xdp_prog is mostly if/else branches handling
the different modes of virtio_net. So remove it and handle running
the program in the per mode handlers.

Signed-off-by: John Fastabend 


Acked-by: Jason Wang 


---
  drivers/net/virtio_net.c |   86 +++---
  1 file changed, 35 insertions(+), 51 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f8ba586..3b49363 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -399,52 +399,6 @@ static bool virtnet_xdp_xmit(struct virtnet_info *vi,
return true;
  }
  
-static u32 do_xdp_prog(struct virtnet_info *vi,

-  struct receive_queue *rq,
-  struct bpf_prog *xdp_prog,
-  void *data, int len)
-{
-   int hdr_padded_len;
-   struct xdp_buff xdp;
-   void *buf;
-   unsigned int qp;
-   u32 act;
-
-   if (vi->mergeable_rx_bufs) {
-   hdr_padded_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
-   xdp.data = data + hdr_padded_len;
-   xdp.data_end = xdp.data + (len - vi->hdr_len);
-   buf = data;
-   } else { /* small buffers */
-   struct sk_buff *skb = data;
-
-   xdp.data = skb->data;
-   xdp.data_end = xdp.data + len;
-   buf = skb->data;
-   }
-
-   act = bpf_prog_run_xdp(xdp_prog, );
-   switch (act) {
-   case XDP_PASS:
-   return XDP_PASS;
-   case XDP_TX:
-   qp = vi->curr_queue_pairs -
-   vi->xdp_queue_pairs +
-   smp_processor_id();
-   xdp.data = buf;
-   if (unlikely(!virtnet_xdp_xmit(vi, rq, >sq[qp], ,
-  data)))
-   trace_xdp_exception(vi->dev, xdp_prog, act);
-   return XDP_TX;
-   default:
-   bpf_warn_invalid_xdp_action(act);
-   case XDP_ABORTED:
-   trace_xdp_exception(vi->dev, xdp_prog, act);
-   case XDP_DROP:
-   return XDP_DROP;
-   }
-}
-
  static struct sk_buff *receive_small(struct net_device *dev,
 struct virtnet_info *vi,
 struct receive_queue *rq,
@@ -460,19 +414,34 @@ static struct sk_buff *receive_small(struct net_device 
*dev,
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
+   struct xdp_buff xdp;
+   unsigned int qp;
u32 act;
  
  		if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags))

goto err_xdp;
-   act = do_xdp_prog(vi, rq, xdp_prog, skb, len);
+
+   xdp.data = skb->data;
+   xdp.data_end = xdp.data + len;
+   act = bpf_prog_run_xdp(xdp_prog, );
+
switch (act) {
case XDP_PASS:
break;
case XDP_TX:
+   qp = vi->curr_queue_pairs -
+   vi->xdp_queue_pairs +
+   smp_processor_id();
+   if (unlikely(!virtnet_xdp_xmit(vi, rq, >sq[qp],
+  , skb)))
+   trace_xdp_exception(vi->dev, xdp_prog, act);
rcu_read_unlock();
goto xdp_xmit;
-   case XDP_DROP:
default:
+   bpf_warn_invalid_xdp_action(act);
+   case XDP_ABORTED:
+   trace_xdp_exception(vi->dev, xdp_prog, act);
+   case XDP_DROP:
goto err_xdp;
}
}
@@ -590,6 +559,9 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
struct page *xdp_page;
+   struct xdp_buff xdp;
+   unsigned int qp;
+   void *data;
u32 act;
  
  		/* This happens when rx buffer size is underestimated */

@@ -612,8 +584,11 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
if (unlikely(hdr->hdr.gso_type))
goto err_xdp;
  
-		act = do_xdp_prog(vi, rq, xdp_prog,

- page_address(xdp_page) + offset, len);
+   data = page_address(xdp_page) + offset;
+   xdp.data = data + vi->hdr_len;
+   xdp.data_end = xdp.data + (len - vi->hdr_len);
+   act = bpf_prog_run_xdp(xdp_prog, );
+
switch (act) {
case XDP_PASS:
/* We can only create skb based on xdp_page. */
@@ -627,13 

[net-next PATCH v2 2/5] virtio_net: factor out xdp handler for readability

[John Fastabend]

At this point the do_xdp_prog is mostly if/else branches handling
the different modes of virtio_net. So remove it and handle running
the program in the per mode handlers.

Signed-off-by: John Fastabend 
---
 drivers/net/virtio_net.c |   86 +++---
 1 file changed, 35 insertions(+), 51 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f8ba586..3b49363 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -399,52 +399,6 @@ static bool virtnet_xdp_xmit(struct virtnet_info *vi,
return true;
 }
 
-static u32 do_xdp_prog(struct virtnet_info *vi,
-  struct receive_queue *rq,
-  struct bpf_prog *xdp_prog,
-  void *data, int len)
-{
-   int hdr_padded_len;
-   struct xdp_buff xdp;
-   void *buf;
-   unsigned int qp;
-   u32 act;
-
-   if (vi->mergeable_rx_bufs) {
-   hdr_padded_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
-   xdp.data = data + hdr_padded_len;
-   xdp.data_end = xdp.data + (len - vi->hdr_len);
-   buf = data;
-   } else { /* small buffers */
-   struct sk_buff *skb = data;
-
-   xdp.data = skb->data;
-   xdp.data_end = xdp.data + len;
-   buf = skb->data;
-   }
-
-   act = bpf_prog_run_xdp(xdp_prog, );
-   switch (act) {
-   case XDP_PASS:
-   return XDP_PASS;
-   case XDP_TX:
-   qp = vi->curr_queue_pairs -
-   vi->xdp_queue_pairs +
-   smp_processor_id();
-   xdp.data = buf;
-   if (unlikely(!virtnet_xdp_xmit(vi, rq, >sq[qp], ,
-  data)))
-   trace_xdp_exception(vi->dev, xdp_prog, act);
-   return XDP_TX;
-   default:
-   bpf_warn_invalid_xdp_action(act);
-   case XDP_ABORTED:
-   trace_xdp_exception(vi->dev, xdp_prog, act);
-   case XDP_DROP:
-   return XDP_DROP;
-   }
-}
-
 static struct sk_buff *receive_small(struct net_device *dev,
 struct virtnet_info *vi,
 struct receive_queue *rq,
@@ -460,19 +414,34 @@ static struct sk_buff *receive_small(struct net_device 
*dev,
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
+   struct xdp_buff xdp;
+   unsigned int qp;
u32 act;
 
if (unlikely(hdr->hdr.gso_type || hdr->hdr.flags))
goto err_xdp;
-   act = do_xdp_prog(vi, rq, xdp_prog, skb, len);
+
+   xdp.data = skb->data;
+   xdp.data_end = xdp.data + len;
+   act = bpf_prog_run_xdp(xdp_prog, );
+
switch (act) {
case XDP_PASS:
break;
case XDP_TX:
+   qp = vi->curr_queue_pairs -
+   vi->xdp_queue_pairs +
+   smp_processor_id();
+   if (unlikely(!virtnet_xdp_xmit(vi, rq, >sq[qp],
+  , skb)))
+   trace_xdp_exception(vi->dev, xdp_prog, act);
rcu_read_unlock();
goto xdp_xmit;
-   case XDP_DROP:
default:
+   bpf_warn_invalid_xdp_action(act);
+   case XDP_ABORTED:
+   trace_xdp_exception(vi->dev, xdp_prog, act);
+   case XDP_DROP:
goto err_xdp;
}
}
@@ -590,6 +559,9 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
struct page *xdp_page;
+   struct xdp_buff xdp;
+   unsigned int qp;
+   void *data;
u32 act;
 
/* This happens when rx buffer size is underestimated */
@@ -612,8 +584,11 @@ static struct sk_buff *receive_mergeable(struct net_device 
*dev,
if (unlikely(hdr->hdr.gso_type))
goto err_xdp;
 
-   act = do_xdp_prog(vi, rq, xdp_prog,
- page_address(xdp_page) + offset, len);
+   data = page_address(xdp_page) + offset;
+   xdp.data = data + vi->hdr_len;
+   xdp.data_end = xdp.data + (len - vi->hdr_len);
+   act = bpf_prog_run_xdp(xdp_prog, );
+
switch (act) {
case XDP_PASS:
/* We can only create skb based on xdp_page. */
@@ -627,13 +602,22 @@ static struct sk_buff *receive_mergeable(struct 
net_device