[Intel-wired-lan] [next PATCH S9 05/15] i40e/i40evf: fix tx hang workaround code

[Catherine Sullivan <catherine.sullivan@intel.com>]

From: Jesse Brandeburg <jesse.brandeburg@intel.com>

The arm writeback (arm_wb) code is used for kicking the tx ring to
make sure any pending work is completed even if interrupts are
disabled. It was running when it didn't need to, and not clearing
the ring->arm_wb state after it was set.  This caused tx hangs
to still occur occasionally when there really was no hang.
Fix this by resetting the variable right after it was used.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Change-ID: I7bf75d552ba9c4bd203d40615213861a24bb5594
---
 drivers/net/ethernet/intel/i40e/i40e_txrx.c   | 3 +--
 drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 738aca6..8a3d596 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -793,8 +793,6 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget)
 	    !test_bit(__I40E_DOWN, &tx_ring->vsi->state) &&
 	    (I40E_DESC_UNUSED(tx_ring) != tx_ring->count))
 		tx_ring->arm_wb = true;
-	else
-		tx_ring->arm_wb = false;
 
 	if (check_for_tx_hang(tx_ring) && i40e_check_tx_hang(tx_ring)) {
 		/* schedule immediate reset if we believe we hung */
@@ -1921,6 +1919,7 @@ int i40e_napi_poll(struct napi_struct *napi, int budget)
 	i40e_for_each_ring(ring, q_vector->tx) {
 		clean_complete &= i40e_clean_tx_irq(ring, vsi->work_limit);
 		arm_wb |= ring->arm_wb;
+		ring->arm_wb = false;
 	}
 
 	/* We attempt to distribute budget to each Rx queue fairly, but don't
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index a584e21..6c353b2 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -309,8 +309,6 @@ static bool i40e_clean_tx_irq(struct i40e_ring *tx_ring, int budget)
 	    !test_bit(__I40E_DOWN, &tx_ring->vsi->state) &&
 	    (I40E_DESC_UNUSED(tx_ring) != tx_ring->count))
 		tx_ring->arm_wb = true;
-	else
-		tx_ring->arm_wb = false;
 
 	if (check_for_tx_hang(tx_ring) && i40e_check_tx_hang(tx_ring)) {
 		/* schedule immediate reset if we believe we hung */
@@ -1367,6 +1365,7 @@ int i40evf_napi_poll(struct napi_struct *napi, int budget)
 	i40e_for_each_ring(ring, q_vector->tx) {
 		clean_complete &= i40e_clean_tx_irq(ring, vsi->work_limit);
 		arm_wb |= ring->arm_wb;
+		ring->arm_wb = false;
 	}
 
 	/* We attempt to distribute budget to each Rx queue fairly, but don't
-- 
1.9.3