From: Eric Dumazet <edumazet@google.com>
Date: Thu, 27 Sep 2018 09:31:55 -0700
Subject: virtio_net: remove ndo_poll_controller
Patch-mainline: v4.19-rc7
Git-commit: 260dd2c3e2aeefbe78065f0737dceae1ceb1196a
References: bsc#1109837
As diagnosed by Song Liu, ndo_poll_controller() can
be very dangerous on loaded hosts, since the cpu
calling ndo_poll_controller() might steal all NAPI
contexts (for all RX/TX queues of the NIC). This capture
can last for unlimited amount of time, since one
cpu is generally not able to drain all the queues under load.
virto_net uses NAPI for TX completions, so we better let core
networking stack call the napi->poll() to avoid the capture.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/virtio_net.c | 14 --------------
1 file changed, 14 deletions(-)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1700,17 +1700,6 @@ static void virtnet_stats(struct net_dev
tot->rx_frame_errors = dev->stats.rx_frame_errors;
}
-#ifdef CONFIG_NET_POLL_CONTROLLER
-static void virtnet_netpoll(struct net_device *dev)
-{
- struct virtnet_info *vi = netdev_priv(dev);
- int i;
-
- for (i = 0; i < vi->curr_queue_pairs; i++)
- napi_schedule(&vi->rq[i].napi);
-}
-#endif
-
static void virtnet_ack_link_announce(struct virtnet_info *vi)
{
rtnl_lock();
@@ -2448,9 +2437,6 @@ static const struct net_device_ops virtn
.ndo_get_stats64 = virtnet_stats,
.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
-#ifdef CONFIG_NET_POLL_CONTROLLER
- .ndo_poll_controller = virtnet_netpoll,
-#endif
.ndo_bpf = virtnet_xdp,
.ndo_xdp_xmit = virtnet_xdp_xmit,
.ndo_features_check = passthru_features_check,