[PATCH 02/12] hinic: remove ndo_poll_controller

[Ike Panhc]

From: Eric Dumazet <edumazet at google.com>

BugLink: https://bugs.launchpad.net/bugs/1820187

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.

hinic uses NAPI for TX completions, so we better let core
networking stack call the napi->poll() to avoid the capture.

Note that hinic_netpoll() was incorrectly scheduling NAPI
on both RX and TX queues.

Signed-off-by: Eric Dumazet <edumazet at google.com>
Cc: Aviad Krawczyk <aviad.krawczyk at huawei.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit e71fb423e0dea3c9f98f0101e965426edfe849cd)
Signed-off-by: Ike Panhc <ike.pan at canonical.com>
---
 .../net/ethernet/huawei/hinic/hinic_main.c    | 20 -------------------
 1 file changed, 20 deletions(-)

diff --git a/drivers/net/ethernet/huawei/hinic/hinic_main.c b/drivers/net/ethernet/huawei/hinic/hinic_main.c
index 09e9da10b786..4a8f82938ed5 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_main.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_main.c
@@ -789,23 +789,6 @@ static void hinic_get_stats64(struct net_device *netdev,
 	stats->tx_errors  = nic_tx_stats->tx_dropped;
 }
 
-#ifdef CONFIG_NET_POLL_CONTROLLER
-static void hinic_netpoll(struct net_device *netdev)
-{
-	struct hinic_dev *nic_dev = netdev_priv(netdev);
-	int i, num_qps;
-
-	num_qps = hinic_hwdev_num_qps(nic_dev->hwdev);
-	for (i = 0; i < num_qps; i++) {
-		struct hinic_txq *txq = &nic_dev->txqs[i];
-		struct hinic_rxq *rxq = &nic_dev->rxqs[i];
-
-		napi_schedule(&txq->napi);
-		napi_schedule(&rxq->napi);
-	}
-}
-#endif
-
 static const struct net_device_ops hinic_netdev_ops = {
 	.ndo_open = hinic_open,
 	.ndo_stop = hinic_close,
@@ -818,9 +801,6 @@ static const struct net_device_ops hinic_netdev_ops = {
 	.ndo_start_xmit = hinic_xmit_frame,
 	.ndo_tx_timeout = hinic_tx_timeout,
 	.ndo_get_stats64 = hinic_get_stats64,
-#ifdef CONFIG_NET_POLL_CONTROLLER
-	.ndo_poll_controller = hinic_netpoll,
-#endif
 };
 
 static void netdev_features_init(struct net_device *netdev)
-- 
2.17.1