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

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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>
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
1 changed files with 5 additions and 3 deletions
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2
drivers/net/virtio_net.c
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@ -2185,6 +2185,7 @@ 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. */ /* Make sure NAPI is not using any XDP TX queues for RX. */
if (netif_running(dev))
for (i = 0; i < vi->max_queue_pairs; i++) for (i = 0; i < vi->max_queue_pairs; i++)
napi_disable(&vi->rq[i].napi); napi_disable(&vi->rq[i].napi);
@ -2205,6 +2206,7 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
} }
if (old_prog) if (old_prog)
bpf_prog_put(old_prog); bpf_prog_put(old_prog);
if (netif_running(dev))
virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi); virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
} }