netdev - [PATCH net 2/2] ionic: Prevent tx_timeout due to frequent doorbell ringing

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Message-ID: <20240813234122.53083-3-brett.creeley@amd.com>
Date: Tue, 13 Aug 2024 16:41:22 -0700
From: Brett Creeley <brett.creeley@....com>
To: <netdev@...r.kernel.org>, <davem@...emloft.net>, <kuba@...nel.org>,
	<edumazet@...gle.com>, <pabeni@...hat.com>
CC: <shannon.nelson@....com>, <brett.creeley@....com>
Subject: [PATCH net 2/2] ionic: Prevent tx_timeout due to frequent doorbell ringing

With recent work to the doorbell workaround code a small hole
was introduced that could cause a tx_timeout. This happens if
the rx dbell_deadline goes beyond the netdev watchdog timeout
set by the driver (i.e. 2 seconds). Fix this by changing the
netdev watchdog timeout to 5 seconds and reduce the max rx
dbell_deadline to 4 seconds.

The test that can reproduce the issue being fixed is a
multi-queue send test via pktgen with the "burst" setting to 1.
This causes the queue's doorbell to be rung on every packet
sent to the driver, which may result in the device missing
doorbells due to the high doorbell rate.

Fixes: 4ded136c78f8 ("ionic: add work item for missed-doorbell check")
Signed-off-by: Brett Creeley <brett.creeley@....com>
---
 drivers/net/ethernet/pensando/ionic/ionic_dev.h | 2 +-
 drivers/net/ethernet/pensando/ionic/ionic_lif.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.h b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
index c647033f3ad2..f2f07bf88545 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_dev.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
@@ -32,7 +32,7 @@
 #define IONIC_ADMIN_DOORBELL_DEADLINE	(HZ / 2)	/* 500ms */
 #define IONIC_TX_DOORBELL_DEADLINE	(HZ / 100)	/* 10ms */
 #define IONIC_RX_MIN_DOORBELL_DEADLINE	(HZ / 100)	/* 10ms */
-#define IONIC_RX_MAX_DOORBELL_DEADLINE	(HZ * 5)	/* 5s */
+#define IONIC_RX_MAX_DOORBELL_DEADLINE	(HZ * 4)	/* 4s */
 
 struct ionic_dev_bar {
 	void __iomem *vaddr;
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
index aa0cc31dfe6e..86774d9922d8 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
@@ -3220,7 +3220,7 @@ int ionic_lif_alloc(struct ionic *ionic)
 	netdev->netdev_ops = &ionic_netdev_ops;
 	ionic_ethtool_set_ops(netdev);
 
-	netdev->watchdog_timeo = 2 * HZ;
+	netdev->watchdog_timeo = 5 * HZ;
 	netif_carrier_off(netdev);
 
 	lif->identity = lid;
-- 
2.17.1