[PATCH][unstable][Artful][SRU Zesty] net: hns: Bugfix for Tx timeout handling in hns driver

[dann frazier]

From: Lin Yun Sheng <linyunsheng at huawei.com>

BugLink: https://bugs.launchpad.net/bugs/1704146

When hns port type is not debug mode, netif_tx_disable is called
when there is a tx timeout, which requires system reboot to return
to normal state. This patch fix this problem by resetting the net
dev.

Fixes: b5996f11ea54 ("net: add Hisilicon Network Subsystem basic ethernet support")
Signed-off-by: Lin Yun Sheng <linyunsheng at huawei.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 76b825ab870be3281edac4ae8a414da6e54b0d3a)
Signed-off-by: dann frazier <dann.frazier at canonical.com>
---
 drivers/net/ethernet/hisilicon/hns/hns_enet.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index bdedea75ddab..34dd3c6f1976 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -1375,13 +1375,20 @@ void hns_nic_net_reset(struct net_device *ndev)
 void hns_nic_net_reinit(struct net_device *netdev)
 {
 	struct hns_nic_priv *priv = netdev_priv(netdev);
+	enum hnae_port_type type = priv->ae_handle->port_type;
 
 	netif_trans_update(priv->netdev);
 	while (test_and_set_bit(NIC_STATE_REINITING, &priv->state))
 		usleep_range(1000, 2000);
 
 	hns_nic_net_down(netdev);
-	hns_nic_net_reset(netdev);
+
+	/* Only do hns_nic_net_reset in debug mode
+	 * because of hardware limitation.
+	 */
+	if (type == HNAE_PORT_DEBUG)
+		hns_nic_net_reset(netdev);
+
 	(void)hns_nic_net_up(netdev);
 	clear_bit(NIC_STATE_REINITING, &priv->state);
 }
@@ -2002,13 +2009,8 @@ static void hns_nic_reset_subtask(struct hns_nic_priv *priv)
 	rtnl_lock();
 	/* put off any impending NetWatchDogTimeout */
 	netif_trans_update(priv->netdev);
+	hns_nic_net_reinit(priv->netdev);
 
-	if (type == HNAE_PORT_DEBUG) {
-		hns_nic_net_reinit(priv->netdev);
-	} else {
-		netif_carrier_off(priv->netdev);
-		netif_tx_disable(priv->netdev);
-	}
 	rtnl_unlock();
 }
 
-- 
2.13.2