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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Heiner Kallweit <hkallweit1@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 5.9 049/757] r8169: fix operation under forced interrupt threading
Date:   Tue, 27 Oct 2020 14:44:59 +0100
Message-Id: <20201027135452.851788913@linuxfoundation.org>
In-Reply-To: <20201027135450.497324313@linuxfoundation.org>
References: <20201027135450.497324313@linuxfoundation.org>
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From: Heiner Kallweit <hkallweit1@gmail.com>

[ Upstream commit 424a646e072a887aa87283b53aa6f8b19c2a7bef ]

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@gmail.com>
Link: https://lore.kernel.org/r/4d3ef84a-c812-5072-918a-22a6f6468310@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/realtek/r8169_main.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4686,7 +4686,7 @@ static int rtl8169_close(struct net_devi
 
 	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);
@@ -4737,8 +4737,8 @@ static int rtl_open(struct net_device *d
 
 	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;
 
@@ -4755,7 +4755,7 @@ out:
 	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);