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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,
        Serge Belyshev <belyshev@depni.sinp.msu.ru>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH 5.8 44/70] r8169: fix issue with forced threading in combination with shared interrupts
Date:   Sat, 31 Oct 2020 12:36:16 +0100
Message-Id: <20201031113501.608327456@linuxfoundation.org>
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References: <20201031113459.481803250@linuxfoundation.org>
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From: Heiner Kallweit <hkallweit1@gmail.com>

[ Upstream commit 2734a24e6e5d18522fbf599135c59b82ec9b2c9e ]

As reported by Serge flag IRQF_NO_THREAD causes an error if the
interrupt is actually shared and the other driver(s) don't have this
flag set. This situation can occur if a PCI(e) legacy interrupt is
used in combination with forced threading.
There's no good way to deal with this properly, therefore we have to
remove flag IRQF_NO_THREAD. For fixing the original forced threading
issue switch to napi_schedule().

Fixes: 424a646e072a ("r8169: fix operation under forced interrupt threading")
Link: https://www.spinics.net/lists/netdev/msg694960.html
Reported-by: Serge Belyshev <belyshev@depni.sinp.msu.ru>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Serge Belyshev <belyshev@depni.sinp.msu.ru>
Link: https://lore.kernel.org/r/b5b53bfe-35ac-3768-85bf-74d1290cf394@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 |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4559,7 +4559,7 @@ static irqreturn_t rtl8169_interrupt(int
 	}
 
 	rtl_irq_disable(tp);
-	napi_schedule_irqoff(&tp->napi);
+	napi_schedule(&tp->napi);
 out:
 	rtl_ack_events(tp, status);
 
@@ -4727,7 +4727,7 @@ static int rtl_open(struct net_device *d
 	rtl_request_firmware(tp);
 
 	retval = request_irq(pci_irq_vector(pdev, 0), rtl8169_interrupt,
-			     IRQF_NO_THREAD | IRQF_SHARED, dev->name, tp);
+			     IRQF_SHARED, dev->name, tp);
 	if (retval < 0)
 		goto err_release_fw_2;