netdev - [PATCH net 2/3] amd-xgbe: handle the corner-case during tx completion

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Date: Wed, 22 Nov 2023 00:44:34 +0530
From: Raju Rangoju <Raju.Rangoju@....com>
To: <netdev@...r.kernel.org>
CC: <davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
	<pabeni@...hat.com>, <Thomas.Lendacky@....com>, <Shyam-sundar.S-k@....com>,
	Raju Rangoju <Raju.Rangoju@....com>
Subject: [PATCH net 2/3] amd-xgbe: handle the corner-case during tx completion

The existing implementation uses software logic to accumulate tx
completions until the specified time (1ms) is met and then poll them.
However, there exists a tiny gap which leads to a race between
resetting and checking the tx_activate flag. Due to this the tx
completions are not reported to upper layer and tx queue timeout
kicks-in restarting the device.

To address this, introduce a tx cleanup mechanism as part of the
periodic maintenance process.

Fixes: c5aa9e3b8156 ("amd-xgbe: Initial AMD 10GbE platform driver")
Acked-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>
Signed-off-by: Raju Rangoju <Raju.Rangoju@....com>
---
 drivers/net/ethernet/amd/xgbe/xgbe-drv.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index 614c0278419b..6b73648b3779 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -682,10 +682,24 @@ static void xgbe_service(struct work_struct *work)
 static void xgbe_service_timer(struct timer_list *t)
 {
 	struct xgbe_prv_data *pdata = from_timer(pdata, t, service_timer);
+	struct xgbe_channel *channel;
+	unsigned int i;
 
 	queue_work(pdata->dev_workqueue, &pdata->service_work);
 
 	mod_timer(&pdata->service_timer, jiffies + HZ);
+
+	if (!pdata->tx_usecs)
+		return;
+
+	for (i = 0; i < pdata->channel_count; i++) {
+		channel = pdata->channel[i];
+		if (!channel->tx_ring || channel->tx_timer_active)
+			break;
+		channel->tx_timer_active = 1;
+		mod_timer(&channel->tx_timer,
+			  jiffies + usecs_to_jiffies(pdata->tx_usecs));
+	}
 }
 
 static void xgbe_init_timers(struct xgbe_prv_data *pdata)
-- 
2.25.1