virtio-net: disable NAPI only when enabled during XDP set

We try to disable NAPI to prevent a single XDP TX queue being used by
multiple cpus. But we don't check if device is up (NAPI is enabled),
this could result stall because of infinite wait in
napi_disable(). Fixing this by checking device state through
netif_running() before.

Fixes: 4941d472bf ("virtio-net: do not reset during XDP set")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jason Wang 2018-02-28 18:20:04 +08:00 committed by David S. Miller
parent ecc832758a
commit 4e09ff5362

View File

@ -2185,8 +2185,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
}
/* Make sure NAPI is not using any XDP TX queues for RX. */
for (i = 0; i < vi->max_queue_pairs; i++)
napi_disable(&vi->rq[i].napi);
if (netif_running(dev))
for (i = 0; i < vi->max_queue_pairs; i++)
napi_disable(&vi->rq[i].napi);
netif_set_real_num_rx_queues(dev, curr_qp + xdp_qp);
err = _virtnet_set_queues(vi, curr_qp + xdp_qp);
@ -2205,7 +2206,8 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
}
if (old_prog)
bpf_prog_put(old_prog);
virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
if (netif_running(dev))
virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
}
return 0;