[PATCH AUTOSEL 4.4 55/64] e1000: Do not perform reset in reset_task if we are already down

[Sasha Levin]

From: Alexander Duyck <alexander.h.du...@linux.intel.com>

[ Upstream commit 49ee3c2ab5234757bfb56a0b3a3cb422f427e3a3 ]

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.du...@linux.intel.com>
Tested-by: Maxim Zhukov <mussitantesmor...@gmail.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirs...@intel.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 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 f958188207fd6..e57aca6239f8e 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -568,8 +568,13 @@ 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);
 }
 
@@ -1456,10 +1461,15 @@ static 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);
-- 
2.25.1