Received-SPF: pass (google.com: domain of linux-kernel+bounces-118560-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
From: Paul Barker <paul.barker.ct@bp.renesas.com>
To: Sergey Shtylyov <s.shtylyov@omp.ru>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>
Cc: Paul Barker <paul.barker.ct@bp.renesas.com>,
	=?UTF-8?q?Niklas=20S=C3=B6derlund?= <niklas.soderlund+renesas@ragnatech.se>,
	netdev@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] net: ravb: Always process TX descriptor ring
Date: Tue, 26 Mar 2024 08:37:39 +0000
Message-Id: <20240326083740.23364-1-paul.barker.ct@bp.renesas.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

The TX queue should be serviced each time the poll function is called,
even if the full RX work budget has been consumed. This prevents
starvation of the TX queue when RX bandwidth usage is high.

Fixes: a0d2f20650e8 ("Renesas Ethernet AVB PTP clock driver")
Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
---
 drivers/net/ethernet/renesas/ravb_main.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index d1be030c8848..4f98e4e2badb 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1324,12 +1324,12 @@ static int ravb_poll(struct napi_struct *napi, int budget)
 	int q = napi - priv->napi;
 	int mask = BIT(q);
 	int quota = budget;
+	bool rearm = true;
 
 	/* Processing RX Descriptor Ring */
 	/* Clear RX interrupt */
 	ravb_write(ndev, ~(mask | RIS0_RESERVED), RIS0);
-	if (ravb_rx(ndev, &quota, q))
-		goto out;
+	rearm = !ravb_rx(ndev, &quota, q);
 
 	/* Processing TX Descriptor Ring */
 	spin_lock_irqsave(&priv->lock, flags);
@@ -1339,6 +1339,9 @@ static int ravb_poll(struct napi_struct *napi, int budget)
 	netif_wake_subqueue(ndev, q);
 	spin_unlock_irqrestore(&priv->lock, flags);
 
+	if (!rearm)
+		goto out;
+
 	napi_complete(napi);
 
 	/* Re-enable RX/TX interrupts */

base-commit: 4cece764965020c22cff7665b18a012006359095
-- 
2.44.0