virtio_net: split XDP_TX kick and XDP_REDIRECT map flushing

The driver was combining XDP_TX virtqueue_kick and XDP_REDIRECT
map flushing (xdp_do_flush_map).  This is suboptimal, these two
flush operations should be kept separate.

The suboptimal behavior was introduced in commit 9267c430c6b6
("virtio-net: add missing virtqueue kick when flushing packets").

Fixes: 9267c430c6b6 ("virtio-net: add missing virtqueue kick when flushing packets")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b6c9a2af37328d1037c3b0ba761256092556167e..53085c63277b4ecfa9d8651543bfb5e545fa73ee 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -53,6 +53,10 @@ module_param(napi_tx, bool, 0644);
 /* Amount of XDP headroom to prepend to packets for use by xdp_adjust_head */
 #define VIRTIO_XDP_HEADROOM 256
 
+/* Separating two types of XDP xmit */
+#define VIRTIO_XDP_TX          BIT(0)
+#define VIRTIO_XDP_REDIR       BIT(1)
+
 /* RX packet size EWMA. The average packet size is used to determine the packet
  * buffer size when refilling RX rings. As the entire RX ring may be refilled
  * at once, the weight is chosen so that the EWMA will be insensitive to short-
@@ -582,7 +586,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
                                     struct receive_queue *rq,
                                     void *buf, void *ctx,
                                     unsigned int len,
-                                    bool *xdp_xmit)
+                                    unsigned int *xdp_xmit)
 {
        struct sk_buff *skb;
        struct bpf_prog *xdp_prog;
@@ -654,14 +658,14 @@ static struct sk_buff *receive_small(struct net_device *dev,
                                trace_xdp_exception(vi->dev, xdp_prog, act);
                                goto err_xdp;
                        }
-                       *xdp_xmit = true;
+                       *xdp_xmit |= VIRTIO_XDP_TX;
                        rcu_read_unlock();
                        goto xdp_xmit;
                case XDP_REDIRECT:
                        err = xdp_do_redirect(dev, &xdp, xdp_prog);
                        if (err)
                                goto err_xdp;
-                       *xdp_xmit = true;
+                       *xdp_xmit |= VIRTIO_XDP_REDIR;
                        rcu_read_unlock();
                        goto xdp_xmit;
                default:
@@ -723,7 +727,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                                         void *buf,
                                         void *ctx,
                                         unsigned int len,
-                                        bool *xdp_xmit)
+                                        unsigned int *xdp_xmit)
 {
        struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
        u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
@@ -818,7 +822,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                                        put_page(xdp_page);
                                goto err_xdp;
                        }
-                       *xdp_xmit = true;
+                       *xdp_xmit |= VIRTIO_XDP_TX;
                        if (unlikely(xdp_page != page))
                                put_page(page);
                        rcu_read_unlock();
@@ -830,7 +834,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                                        put_page(xdp_page);
                                goto err_xdp;
                        }
-                       *xdp_xmit = true;
+                       *xdp_xmit |= VIRTIO_XDP_REDIR;
                        if (unlikely(xdp_page != page))
                                put_page(page);
                        rcu_read_unlock();
@@ -939,7 +943,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 }
 
 static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
-                      void *buf, unsigned int len, void **ctx, bool *xdp_xmit)
+                      void *buf, unsigned int len, void **ctx,
+                      unsigned int *xdp_xmit)
 {
        struct net_device *dev = vi->dev;
        struct sk_buff *skb;
@@ -1232,7 +1237,8 @@ static void refill_work(struct work_struct *work)
        }
 }
 
-static int virtnet_receive(struct receive_queue *rq, int budget, bool *xdp_xmit)
+static int virtnet_receive(struct receive_queue *rq, int budget,
+                          unsigned int *xdp_xmit)
 {
        struct virtnet_info *vi = rq->vq->vdev->priv;
        unsigned int len, received = 0, bytes = 0;
@@ -1321,7 +1327,7 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
        struct virtnet_info *vi = rq->vq->vdev->priv;
        struct send_queue *sq;
        unsigned int received, qp;
-       bool xdp_xmit = false;
+       unsigned int xdp_xmit = 0;
 
        virtnet_poll_cleantx(rq);
 
@@ -1331,12 +1337,14 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
        if (received < budget)
                virtqueue_napi_complete(napi, rq->vq, received);
 
-       if (xdp_xmit) {
+       if (xdp_xmit & VIRTIO_XDP_REDIR)
+               xdp_do_flush_map();
+
+       if (xdp_xmit & VIRTIO_XDP_TX) {
                qp = vi->curr_queue_pairs - vi->xdp_queue_pairs +
                     smp_processor_id();
                sq = &vi->sq[qp];
                virtqueue_kick(sq->vq);
-               xdp_do_flush_map();
        }
 
        return received;