netdev - [PATCH net-next 06/12] ionic: Check stop no restart

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Message-ID: <20240229193935.14197-7-shannon.nelson@amd.com>
Date: Thu, 29 Feb 2024 11:39:29 -0800
From: Shannon Nelson <shannon.nelson@....com>
To: <netdev@...r.kernel.org>, <davem@...emloft.net>, <kuba@...nel.org>,
	<edumazet@...gle.com>, <pabeni@...hat.com>
CC: <brett.creeley@....com>, <drivers@...sando.io>, Shannon Nelson
	<shannon.nelson@....com>
Subject: [PATCH net-next 06/12] ionic: Check stop no restart

From: Brett Creeley <brett.creeley@....com>

If there is a lot of transmit traffic the driver can get into a
situation that the device is starved due to the doorbell never
being rung. This can happen if xmit_more is set constantly
and __netdev_tx_sent_queue() keeps returning false. Fix this
by checking if the queue needs to be stopped right before
calling __netdev_tx_sent_queue(). Use MAX_SKB_FRAGS + 1 as the
stop condition because that's the maximum number of frags
supported for non-TSO transmit.

Signed-off-by: Brett Creeley <brett.creeley@....com>
Signed-off-by: Shannon Nelson <shannon.nelson@....com>
---
 drivers/net/ethernet/pensando/ionic/ionic_txrx.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 1397a0dcf794..d9e23fc78e6b 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -1665,9 +1665,14 @@ static int ionic_tx(struct ionic_queue *q, struct sk_buff *skb)
 	stats->pkts++;
 	stats->bytes += skb->len;
 
-	if (!ionic_txq_hwstamp_enabled(q))
-		ring_dbell = __netdev_tx_sent_queue(q_to_ndq(q), skb->len,
+	if (!ionic_txq_hwstamp_enabled(q)) {
+		struct netdev_queue *ndq = q_to_ndq(q);
+
+		if (unlikely(!ionic_q_has_space(q, MAX_SKB_FRAGS + 1)))
+			netif_tx_stop_queue(ndq);
+		ring_dbell = __netdev_tx_sent_queue(ndq, skb->len,
 						    netdev_xmit_more());
+	}
 	ionic_txq_post(q, ring_dbell, ionic_tx_clean, skb);
 
 	return 0;
-- 
2.17.1