netdev - [PATCH net] ionic: tame the watchdog timer on reconfig

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Message-Id: <20200618172904.53814-1-snelson@pensando.io>
Date:   Thu, 18 Jun 2020 10:29:04 -0700
From:   Shannon Nelson <snelson@...sando.io>
To:     netdev@...r.kernel.org, davem@...emloft.net
Cc:     Shannon Nelson <snelson@...sando.io>
Subject: [PATCH net] ionic: tame the watchdog timer on reconfig

Even with moving netif_tx_disable() to an earlier point when
taking down the queues for a reconfiguration, we still end
up with the occasional netdev watchdog Tx Timeout complaint.
The old method of using netif_trans_update() works fine for
queue 0, but has no effect on the remaining queues.  Using
netif_device_detach() allows us to signal to the watchdog to
ignore us for the moment.

Fixes: beead698b173 ("ionic: Add the basic NDO callbacks for netdev support")
Signed-off-by: Shannon Nelson <snelson@...sando.io>
---
 drivers/net/ethernet/pensando/ionic/ionic_lif.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
index 8f29ef133743..aaa00edd9d5b 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
@@ -1694,15 +1694,15 @@ static void ionic_stop_queues(struct ionic_lif *lif)
 	if (!test_and_clear_bit(IONIC_LIF_F_UP, lif->state))
 		return;
 
-	ionic_txrx_disable(lif);
 	netif_tx_disable(lif->netdev);
+	ionic_txrx_disable(lif);
 }
 
 int ionic_stop(struct net_device *netdev)
 {
 	struct ionic_lif *lif = netdev_priv(netdev);
 
-	if (!netif_device_present(netdev))
+	if (test_bit(IONIC_LIF_F_FW_RESET, lif->state))
 		return 0;
 
 	ionic_stop_queues(lif);
@@ -1985,18 +1985,19 @@ int ionic_reset_queues(struct ionic_lif *lif)
 	bool running;
 	int err = 0;
 
-	/* Put off the next watchdog timeout */
-	netif_trans_update(lif->netdev);
-
 	err = ionic_wait_for_bit(lif, IONIC_LIF_F_QUEUE_RESET);
 	if (err)
 		return err;
 
 	running = netif_running(lif->netdev);
-	if (running)
+	if (running) {
+		netif_device_detach(lif->netdev);
 		err = ionic_stop(lif->netdev);
-	if (!err && running)
+	}
+	if (!err && running) {
 		ionic_open(lif->netdev);
+		netif_device_attach(lif->netdev);
+	}
 
 	clear_bit(IONIC_LIF_F_QUEUE_RESET, lif->state);
 
-- 
2.17.1