Patch "e1000: Do not perform reset in reset_task if we are already down" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    e1000: Do not perform reset in reset_task if we are already down

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     e1000-do-not-perform-reset-in-reset_task-if-we-are-a.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 2b16d89d9a63b5008cb9df08e10efb5b3e312169
Author: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Date:   Fri Apr 17 09:35:31 2020 -0700

    e1000: Do not perform reset in reset_task if we are already down
    
    [ 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.duyck@xxxxxxxxxxxxxxx>
    Tested-by: Maxim Zhukov <mussitantesmortem@xxxxxxxxx>
    Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 47b867c64b147..195108858f38f 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);