[net PATCH v3 3/5] virtio_net: factor out xdp handler for readability

John Fastabend
2017-01-13T02:51:40Z

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 <john.r.fastabend@intel.com>
---
drivers/net/virtio_net.c | 76 +++++++++++++++++-----------------------------
1 file changed, 28 insertions(+), 48 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 43cb2e0..ec54644 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -388,49 +388,6 @@ static void virtnet_xdp_xmit(struct virtnet_info *vi,
virtqueue_kick(sq->vq);
}

-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, &xdp);
- 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;
- virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp, data);
- return XDP_TX;
- default:
- bpf_warn_invalid_xdp_action(act);
- case XDP_ABORTED:
- case XDP_DROP:
- return XDP_DROP;
- }
-}
-
static struct sk_buff *receive_small(struct net_device *dev,
struct virtnet_info *vi,
struct receive_queue *rq,
@@ -446,19 +403,30 @@ 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, &xdp);
switch (act) {
case XDP_PASS:
break;
case XDP_TX:
+ qp = vi->curr_queue_pairs -
+ vi->xdp_queue_pairs +
+ smp_processor_id();
+ virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp, skb);
rcu_read_unlock();
goto xdp_xmit;
- case XDP_DROP:
default:
+ bpf_warn_invalid_xdp_action(act);
+ case XDP_ABORTED:
+ case XDP_DROP:
goto err_xdp;
}
}
@@ -575,7 +543,11 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
rcu_read_lock();
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
+ int desc_room = sizeof(struct virtio_net_hdr_mrg_rxbuf);
struct page *xdp_page;
+ struct xdp_buff xdp;
+ unsigned int qp;
+ void *data;
u32 act;

/* This happens when rx buffer size is underestimated */
@@ -598,8 +570,10 @@ 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 + desc_room;
+ xdp.data_end = xdp.data + (len - vi->hdr_len);
+ act = bpf_prog_run_xdp(xdp_prog, &xdp);
switch (act) {
case XDP_PASS:
/* We can only create skb based on xdp_page. */
@@ -613,13 +587,19 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
}
break;
case XDP_TX:
+ qp = vi->curr_queue_pairs -
+ vi->xdp_queue_pairs +
+ smp_processor_id();
+ virtnet_xdp_xmit(vi, rq, &vi->sq[qp], &xdp, data);
ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);
if (unlikely(xdp_page != page))
goto err_xdp;
rcu_read_unlock();
goto xdp_xmit;
- case XDP_DROP:
default:
+ bpf_warn_invalid_xdp_action(act);
+ case XDP_ABORTED:
+ case XDP_DROP:
if (unlikely(xdp_page != page))
__free_pages(xdp_page, 0);
ewma_pkt_len_add(&rq->mrg_avg_pkt_len, len);