[net-next v2 01/11] ixbge: Protect ixgbe_down with __IXGBE_DOWN bit

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

From: Mark Rustad <mark.d.rustad@intel.com>

The ixgbe_down function can now prevent multiple executions by
doing test_and_set_bit on __IXGBE_DOWN. This did not work before
introduction of the __IXGBE_REMOVED bit, because of overloading
of __IXGBE_DOWN. Also add smp_mb__before_clear_bit call before
clearing the __IXGBE_DOWN bit.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index cc06854..90a0b4a 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -4572,6 +4572,7 @@ static void ixgbe_up_complete(struct ixgbe_adapter *adapter)
 	if (hw->mac.ops.enable_tx_laser)
 		hw->mac.ops.enable_tx_laser(hw);
 
+	smp_mb__before_clear_bit();
 	clear_bit(__IXGBE_DOWN, &adapter->state);
 	ixgbe_napi_enable_all(adapter);
 
@@ -4783,7 +4784,8 @@ void ixgbe_down(struct ixgbe_adapter *adapter)
 	int i;
 
 	/* signal that we are down to the interrupt handler */
-	set_bit(__IXGBE_DOWN, &adapter->state);
+	if (test_and_set_bit(__IXGBE_DOWN, &adapter->state))
+		return; /* do nothing if already down */
 
 	/* disable receives */
 	rxctrl = IXGBE_READ_REG(hw, IXGBE_RXCTRL);
-- 
1.8.3.1