[bpf-next V1-RFC PATCH 11/14] virtio_net: setup xdp_rxq_info

[Jesper Dangaard Brouer]

The virtio_net driver doesn't dynamically change the RX-ring queue
layout and backing pages, but instead reject XDP setup if all the
conditions for XDP is not meet.  Thus, the xdp_rxq_info also remains
fairly static.  This allow us to simply add the init+reg/unreg to
net_device open/close functions.

Driver hook points for xdp_rxq_info:
 * init+reg: virtnet_open
 * unreg   : virtnet_close

Cc: "Michael S. Tsirkin" <m...@redhat.com>
Cc: Jason Wang <jasow...@redhat.com>
Cc: virtualizat...@lists.linux-foundation.org
Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
---
 drivers/net/virtio_net.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 19a985ef9104..9792183befbf 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -31,6 +31,7 @@
 #include <linux/average.h>
 #include <linux/filter.h>
 #include <net/route.h>
+#include <net/xdp.h>
 
 static int napi_weight = NAPI_POLL_WEIGHT;
 module_param(napi_weight, int, 0444);
@@ -115,6 +116,8 @@ struct receive_queue {
 
        /* Name of this receive queue: input.$index */
        char name[40];
+
+       struct xdp_rxq_info xdp_rxq;
 };
 
 struct virtnet_info {
@@ -556,6 +559,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
                xdp.data = xdp.data_hard_start + xdp_headroom;
                xdp_set_data_meta_invalid(&xdp);
                xdp.data_end = xdp.data + len;
+               xdp.rxq = &rq->xdp_rxq;
                orig_data = xdp.data;
                act = bpf_prog_run_xdp(xdp_prog, &xdp);
 
@@ -1229,6 +1233,13 @@ static int virtnet_open(struct net_device *dev)
                        /* Make sure we have some buffers: if oom use wq. */
                        if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
                                schedule_delayed_work(&vi->refill, 0);
+
+               /* XDP RX queue info */
+               xdp_rxq_info_init(&vi->rq[i].xdp_rxq);
+               vi->rq[i].xdp_rxq.dev = dev;
+               vi->rq[i].xdp_rxq.queue_index = i;
+               xdp_rxq_info_reg(&vi->rq[i].xdp_rxq);
+
                virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
                virtnet_napi_tx_enable(vi, vi->sq[i].vq, &vi->sq[i].napi);
        }
@@ -1557,6 +1568,7 @@ static int virtnet_close(struct net_device *dev)
        cancel_delayed_work_sync(&vi->refill);
 
        for (i = 0; i < vi->max_queue_pairs; i++) {
+               xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
                napi_disable(&vi->rq[i].napi);
                virtnet_napi_tx_disable(&vi->sq[i].napi);
        }