From: Jason Wang <jasowang@redhat.com>
Date: Wed, 28 Feb 2018 18:20:04 +0800

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@redhat.com>

Yes, mis-paired NAPI enable/disable are really a pain.

Probably, we can do something in the interfaces or mechanisms to make
this less error prone and less fragile.

Anyways, applied and queued up for -stable, thanks!