[PATCH net] ice: fix netdev bring-up and bring-down in self-test

[Aleksandr Loktionov <aleksandr.loktionov@intel.com>]

From: Konstantin Ilichev <konstantin.ilichev@intel.com>

When an offline self-test is initiated with ethtool -t, any ongoing
traffic could get stuck because ice_stop() and ice_open() are called
without letting the OS know about state transitions.  In most cases
a write() system call would block.

Fix this by calling dev_change_flags() to bring the netdev up and
down, which ensures ndo_open()/ndo_stop() are called and all watchers
are notified correctly.

Fixes: 0e674aeb0b77 ("ice: Add handler for ethtool selftest")
Cc: stable@vger.kernel.org
Co-developed-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Signed-off-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Signed-off-by: Konstantin Ilichev <konstantin.ilichev@intel.com>
Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
---

 drivers/net/ethernet/intel/ice/ice_ethtool.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
index 96d95af..2a4f06f 100644
--- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
+++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
@@ -1416,7 +1416,7 @@ ice_self_test(struct net_device *netdev, struct ethtool_test *eth_test,
 		/* If the device is online then take it offline */
 		if (if_running)
 			/* indicate we're in test mode */
-			ice_stop(netdev);
+			dev_change_flags(netdev, netdev->flags & ~IFF_UP, NULL);
 
 		data[ICE_ETH_TEST_LINK] = ice_link_test(netdev);
 		data[ICE_ETH_TEST_EEPROM] = ice_eeprom_test(netdev);
@@ -1434,10 +1434,12 @@ ice_self_test(struct net_device *netdev, struct ethtool_test *eth_test,
 		clear_bit(ICE_TESTING, pf->state);
 
 		if (if_running) {
-			int status = ice_open(netdev);
+			int status = dev_change_flags(netdev,
+						      netdev->flags | IFF_UP,
+						      NULL);
 
 			if (status) {
-				dev_err(dev, "Could not open device %s, err %d\n",
+				dev_err(dev, "Could not bring up device %s, err %d\n",
 					pf->int_name, status);
 			}
 		}
-- 
2.52.0