linux-kernel - [PATCH] soc: qcom: aoss: remove spurious IRQF

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Message-Id: <20220127173554.158111-1-daniel.thompson@linaro.org>
Date:   Thu, 27 Jan 2022 17:35:54 +0000
From:   Daniel Thompson <daniel.thompson@...aro.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Daniel Thompson <daniel.thompson@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] soc: qcom: aoss: remove spurious IRQF_ONESHOT flags

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.

Signed-off-by: Daniel Thompson <daniel.thompson@...aro.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 cbe5e39fdaeb0..83f1edcbf7a33 100644
--- a/drivers/soc/qcom/qcom_aoss.c
+++ b/drivers/soc/qcom/qcom_aoss.c
@@ -497,7 +497,7 @@ 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");

base-commit: e783362eb54cd99b2cac8b3a9aeac942e6f6ac07
prerequisite-patch-id: 59cdecee7d1b3bdd110f0d01790b92428b91862a
--
2.34.1