linux-kernel - [PATCH 4.4 28/40] e1000e: start network tx queue only when link is up

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Message-Id: <20190718030049.487065577@linuxfoundation.org>
Date:   Thu, 18 Jul 2019 12:02:24 +0900
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Konstantin Khlebnikov <khlebnikov@...dex-team.ru>,
        Alexander Duyck <alexander.duyck@...il.com>,
        Joseph Yasi <joe.yasi@...il.com>,
        Aaron Brown <aaron.f.brown@...el.com>,
        Oleksandr Natalenko <oleksandr@...hat.com>,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [PATCH 4.4 28/40] e1000e: start network tx queue only when link is up

From: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>

commit d17ba0f616a08f597d9348c372d89b8c0405ccf3 upstream.

Driver does not want to keep packets in Tx queue when link is lost.
But present code only reset NIC to flush them, but does not prevent
queuing new packets. Moreover reset sequence itself could generate
new packets via netconsole and NIC falls into endless reset loop.

This patch wakes Tx queue only when NIC is ready to send packets.

This is proper fix for problem addressed by commit 0f9e980bf5ee
("e1000e: fix cyclic resets at link up with active tx").

Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
Suggested-by: Alexander Duyck <alexander.duyck@...il.com>
Tested-by: Joseph Yasi <joe.yasi@...il.com>
Tested-by: Aaron Brown <aaron.f.brown@...el.com>
Tested-by: Oleksandr Natalenko <oleksandr@...hat.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/net/ethernet/intel/e1000e/netdev.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -4171,7 +4171,7 @@ int e1000e_up(struct e1000_adapter *adap
 		e1000_configure_msix(adapter);
 	e1000_irq_enable(adapter);
 
-	netif_start_queue(adapter->netdev);
+	/* Tx queue started by watchdog timer when link is up */
 
 	/* fire a link change interrupt to start the watchdog */
 	if (adapter->msix_entries)
@@ -4539,6 +4539,7 @@ static int e1000_open(struct net_device
 	pm_runtime_get_sync(&pdev->dev);
 
 	netif_carrier_off(netdev);
+	netif_stop_queue(netdev);
 
 	/* allocate transmit descriptors */
 	err = e1000e_setup_tx_resources(adapter->tx_ring);
@@ -4599,7 +4600,6 @@ static int e1000_open(struct net_device
 	e1000_irq_enable(adapter);
 
 	adapter->tx_hang_recheck = false;
-	netif_start_queue(netdev);
 
 	hw->mac.get_link_status = true;
 	pm_runtime_put(&pdev->dev);
@@ -5226,6 +5226,7 @@ static void e1000_watchdog_task(struct w
 			if (phy->ops.cfg_on_link_up)
 				phy->ops.cfg_on_link_up(hw);
 
+			netif_wake_queue(netdev);
 			netif_carrier_on(netdev);
 
 			if (!test_bit(__E1000_DOWN, &adapter->state))
@@ -5239,6 +5240,7 @@ static void e1000_watchdog_task(struct w
 			/* Link status message must follow this format */
 			pr_info("%s NIC Link is Down\n", adapter->netdev->name);
 			netif_carrier_off(netdev);
+			netif_stop_queue(netdev);
 			if (!test_bit(__E1000_DOWN, &adapter->state))
 				mod_timer(&adapter->phy_info_timer,
 					  round_jiffies(jiffies + 2 * HZ));