4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Wang <jasowang@xxxxxxxxxx>
[ Upstream commit 4e09ff5362843dff3accfa84c805c7f3a99de9cd ]
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: 4941d472bf95b ("virtio-net: do not reset during XDP set")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1995,8 +1995,9 @@ static int virtnet_xdp_set(struct net_de
}
/* 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);
@@ -2015,7 +2016,8 @@ static int virtnet_xdp_set(struct net_de
}
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;