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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,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0315/1017] soc: qcom: aoss: remove spurious IRQF_ONESHOT flags
Date:   Tue,  5 Apr 2022 09:20:28 +0200
Message-Id: <20220405070403.627715914@linuxfoundation.org>
In-Reply-To: <20220405070354.155796697@linuxfoundation.org>
References: <20220405070354.155796697@linuxfoundation.org>
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From: Daniel Thompson <daniel.thompson@linaro.org>

[ Upstream commit 8030cb9a55688c1339edd284d9d6ce5f9fc75160 ]

Quoting the header comments, IRQF_ONESHOT is "Used by threaded interrupts
which need to keep the irq line disabled until the threaded handler has
been run.". When applied to an interrupt that doesn't request a threaded
irq then IRQF_ONESHOT has a lesser known (undocumented?) side effect,
which it to disable the forced threading of the irq. For "normal" kernels
(without forced threading) then, if there is no thread_fn, then
IRQF_ONESHOT is a nop.

In this case disabling forced threading is not appropriate for this driver
because it calls wake_up_all() and this API cannot be called from
no-thread interrupt handlers on PREEMPT_RT systems (deadlock risk, triggers
sleeping-while-atomic warnings).

Fix this by removing IRQF_ONESHOT.

Fixes: 2209481409b7 ("soc: qcom: Add AOSS QMP driver")
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
[bjorn: Added Fixes tag]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220127173554.158111-1-daniel.thompson@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/soc/qcom/qcom_aoss.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
index e234d78b33e7..55c156aaf68a 100644
--- a/drivers/soc/qcom/qcom_aoss.c
+++ b/drivers/soc/qcom/qcom_aoss.c
@@ -501,7 +501,7 @@ static int qmp_probe(struct platform_device *pdev)
 	}
 
 	irq = platform_get_irq(pdev, 0);
-	ret = devm_request_irq(&pdev->dev, irq, qmp_intr, IRQF_ONESHOT,
+	ret = devm_request_irq(&pdev->dev, irq, qmp_intr, 0,
 			       "aoss-qmp", qmp);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to request interrupt\n");
-- 
2.34.1