From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Jason Wang <jasowang@redhat.com>
Subject: [PATCH net] virtio-net: disable NAPI only when enabled during XDP set
Date: Wed, 28 Feb 2018 18:20:04 +0800 [thread overview]
Message-ID: <1519813204-10002-1-git-send-email-jasowang@redhat.com> (raw)
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>
---
drivers/net/virtio_net.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 9bb9e56..2d54123 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -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;
--
2.7.4
next reply other threads:[~2018-02-28 10:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-28 10:20 Jason Wang [this message]
2018-02-28 15:27 ` [PATCH net] virtio-net: disable NAPI only when enabled during XDP set Michael S. Tsirkin
2018-02-28 17:22 ` David Miller
2018-02-28 19:02 ` Ben Greear
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