netdev - [PATCH net] r8169: fix operation under forced interrupt threading

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Message-ID: <4d3ef84a-c812-5072-918a-22a6f6468310@gmail.com>
Date:   Sun, 18 Oct 2020 18:38:59 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Jakub Kicinski <kuba@...nel.org>,
        David Miller <davem@...emloft.net>,
        Realtek linux nic maintainers <nic_swsd@...ltek.com>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net] r8169: fix operation under forced interrupt threading

For several network drivers it was reported that using
__napi_schedule_irqoff() is unsafe with forced threading. One way to
fix this is switching back to __napi_schedule, but then we lose the
benefit of the irqoff version in general. As stated by Eric it doesn't
make sense to make the minimal hard irq handlers in drivers using NAPI
a thread. Therefore ensure that the hard irq handler is never
thread-ified.

Fixes: 9a899a35b0d6 ("r8169: switch to napi_schedule_irqoff")
Link: https://lkml.org/lkml/2020/10/18/19
Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/net/ethernet/realtek/r8169_main.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 7d366b036..3b6ddc706 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4694,7 +4694,7 @@ static int rtl8169_close(struct net_device *dev)
 
 	phy_disconnect(tp->phydev);
 
-	pci_free_irq(pdev, 0, tp);
+	free_irq(pci_irq_vector(pdev, 0), tp);
 
 	dma_free_coherent(&pdev->dev, R8169_RX_RING_BYTES, tp->RxDescArray,
 			  tp->RxPhyAddr);
@@ -4745,8 +4745,8 @@ static int rtl_open(struct net_device *dev)
 
 	rtl_request_firmware(tp);
 
-	retval = pci_request_irq(pdev, 0, rtl8169_interrupt, NULL, tp,
-				 dev->name);
+	retval = request_irq(pci_irq_vector(pdev, 0), rtl8169_interrupt,
+			     IRQF_NO_THREAD | IRQF_SHARED, dev->name, tp);
 	if (retval < 0)
 		goto err_release_fw_2;
 
@@ -4763,7 +4763,7 @@ static int rtl_open(struct net_device *dev)
 	return retval;
 
 err_free_irq:
-	pci_free_irq(pdev, 0, tp);
+	free_irq(pci_irq_vector(pdev, 0), tp);
 err_release_fw_2:
 	rtl_release_firmware(tp);
 	rtl8169_rx_clear(tp);
-- 
2.28.0