From 0411e3d3435ad66957c2e3d08f6356e9ce7b470f Mon Sep 17 00:00:00 2001
From: Joakim Zhang <qiangqing.zhang@nxp.com>
Date: Thu, 25 Feb 2021 17:01:11 +0800
Subject: [PATCH 10/19] net: stmmac: fix watchdog timeout during suspend/resume
 stress test
Git-commit: c511819d138de38e1637eedb645c207e09680d0f
Patch-mainline: v5.12-rc3
References: git-fixes

stmmac_xmit() call stmmac_tx_timer_arm() at the end to modify tx timer to
do the transmission cleanup work. Imagine such a situation, stmmac enters
suspend immediately after tx timer modified, it's expire callback
stmmac_tx_clean() would not be invoked. This could affect BQL, since
netdev_tx_sent_queue() has been called, but netdev_tx_completed_queue()
have not been involved, as a result, dql_avail(&dev_queue->dql) finally
always return a negative value.

__dev_queue_xmit->__dev_xmit_skb->qdisc_run->__qdisc_run->qdisc_restart->dequeue_skb:
	if ((q->flags & TCQ_F_ONETXQUEUE) &&
		netif_xmit_frozen_or_stopped(txq)) // __QUEUE_STATE_STACK_XOFF is set

Net core will stop transmitting any more. Finillay, net watchdong would timeout.
To fix this issue, we should call netdev_tx_reset_queue() in stmmac_resume().

Fixes: 54139cf3bb33 ("net: stmmac: adding multiple buffers for rx")
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b2a313ef33ec..3df7cd7a2216 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4450,6 +4450,8 @@ static void stmmac_reset_queues_param(struct stmmac_priv *priv)
 		tx_q->cur_tx = 0;
 		tx_q->dirty_tx = 0;
 		tx_q->mss = 0;
+
+		netdev_tx_reset_queue(netdev_get_tx_queue(priv->dev, queue));
 	}
 }
 
-- 
2.16.4