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