virtio-net: add missing virtqueue kick when flushing packets

BugLink: http://bugs.launchpad.net/bugs/1775483
[ Upstream commit 9267c430c6b6f4c0120e3c6bb847313d633f02a6 ]

We tends to batch submitting packets during XDP_TX. This requires to
kick virtqueue after a batch, we tried to do it through
xdp_do_flush_map() which only makes sense for devmap not XDP_TX. So
explicitly kick the virtqueue in this case.

Reported-by: Kimitoshi Takahashi <ktaka@nii.ac.jp>
Tested-by: Kimitoshi Takahashi <ktaka@nii.ac.jp>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Fixes: 186b3c998c50 ("virtio-net: support XDP_REDIRECT")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5ef484dd30e76bc6857d4cbcaaee009bc1e0de91..69edfe25b2240bacc0cb513974dc1fd41129b601 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1209,7 +1209,9 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
 {
        struct receive_queue *rq =
                container_of(napi, struct receive_queue, napi);
-       unsigned int received;
+       struct virtnet_info *vi = rq->vq->vdev->priv;
+       struct send_queue *sq;
+       unsigned int received, qp;
        bool xdp_xmit = false;
 
        virtnet_poll_cleantx(rq);
@@ -1220,8 +1222,13 @@ 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) {
+               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;
 }