netdev - [net-next v2 05/15] e1000: Do not perform reset in reset

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Message-Id: <20200522001108.1675149-6-jeffrey.t.kirsher@intel.com>
Date:   Thu, 21 May 2020 17:10:58 -0700
From:   Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:     davem@...emloft.net
Cc:     Alexander Duyck <alexander.h.duyck@...ux.intel.com>,
        netdev@...r.kernel.org, nhorman@...hat.com, sassmann@...hat.com,
        Maxim Zhukov <mussitantesmortem@...il.com>,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next v2 05/15] e1000: Do not perform reset in reset_task if we are already down

From: Alexander Duyck <alexander.h.duyck@...ux.intel.com>

We are seeing a deadlock in e1000 down when NAPI is being disabled. Looking
over the kernel function trace of the system it appears that the interface
is being closed and then a reset is hitting which deadlocks the interface
as the NAPI interface is already disabled.

To prevent this from happening I am disabling the reset task when
__E1000_DOWN is already set. In addition code has been added so that we set
the __E1000_DOWN while holding the __E1000_RESET flag in e1000_close in
order to guarantee that the reset task will not run after we have started
the close call.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...ux.intel.com>
Tested-by: Maxim Zhukov <mussitantesmortem@...il.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
 drivers/net/ethernet/intel/e1000/e1000_main.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 05bc6e216bca..d9fa4600f745 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -542,8 +542,13 @@ void e1000_reinit_locked(struct e1000_adapter *adapter)
 	WARN_ON(in_interrupt());
 	while (test_and_set_bit(__E1000_RESETTING, &adapter->flags))
 		msleep(1);
-	e1000_down(adapter);
-	e1000_up(adapter);
+
+	/* only run the task if not already down */
+	if (!test_bit(__E1000_DOWN, &adapter->flags)) {
+		e1000_down(adapter);
+		e1000_up(adapter);
+	}
+
 	clear_bit(__E1000_RESETTING, &adapter->flags);
 }
 
@@ -1433,10 +1438,15 @@ int e1000_close(struct net_device *netdev)
 	struct e1000_hw *hw = &adapter->hw;
 	int count = E1000_CHECK_RESET_COUNT;
 
-	while (test_bit(__E1000_RESETTING, &adapter->flags) && count--)
+	while (test_and_set_bit(__E1000_RESETTING, &adapter->flags) && count--)
 		usleep_range(10000, 20000);
 
-	WARN_ON(test_bit(__E1000_RESETTING, &adapter->flags));
+	WARN_ON(count < 0);
+
+	/* signal that we're down so that the reset task will no longer run */
+	set_bit(__E1000_DOWN, &adapter->flags);
+	clear_bit(__E1000_RESETTING, &adapter->flags);
+
 	e1000_down(adapter);
 	e1000_power_down_phy(adapter);
 	e1000_free_irq(adapter);
-- 
2.26.2