[PATCH net v6 3/4] net: ethernet: oa_tc6: Disable tx queues on fatal error

Previously, TX queue interface was stopped when
disable_traffic flag was set, which would indicate fatal
error. It is more appropriate to disable the queue as,
unless driver is unloaded and reloaded, there is no recovery
after disable_traffic is set.

Queues may be re-enabled inadvertently by other layers.
Intention of disable_traffic is only to stop the traffic
from flowing on fatal error.

Fixes: b542d13fab0f ("net: ethernet: oa_tc6: Interrupt is active low, level triggered.")
Signed-off-by: Selvamani Rajagopal <[email protected]>

---
changes in v6
  - Updated the comment and commit message to reflect the
    usage of disable_traffic
changes in v5
  - Changed the commit message to accurately reflect the
    changes
changes in v4
  - Reverted the change that turned carrier off on disable_traffic,
    as it may have side effects
changes in v3
  - New patch. Carrier marked off once disable_traffic is set
---
 drivers/net/ethernet/oa_tc6.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/oa_tc6.c b/drivers/net/ethernet/oa_tc6.c
index 09bc293fb75b..5354ed3ece7e 100644
--- a/drivers/net/ethernet/oa_tc6.c
+++ b/drivers/net/ethernet/oa_tc6.c
@@ -730,6 +730,12 @@ static void oa_tc6_disable_traffic(struct oa_tc6 *tc6)
 	skb = oa_tc6_detach_waiting_tx_skb(tc6);
 	spin_unlock_bh(&tc6->tx_skb_lock);
 
+	/* disable_traffic, when set, is a point of no return to working
+	 * state. TX queues are disabled. In some cases, upper layer or
+	 * vendor code may inadvertently enable the queue. Intention of
+	 * the disable_traffic flag is to stop traffic from flowing.
+	 */
+	netif_tx_disable(tc6->netdev);
 	oa_tc6_drop_tx_skb(tc6, skb);
 	oa_tc6_free_ongoing_skbs(tc6);
 	oa_tc6_write_register(tc6, OA_TC6_REG_INT_MASK0, regval);

-- 
2.43.0