linux-kernel - [PATCH 2/2] regulator: qcom-labibb: Use disable_irq

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Date:   Tue, 2 Feb 2021 09:37:58 +0200
From:   Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
To:     matti.vaittinen@...rohmeurope.com, mazziesaccount@...il.com
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] regulator: qcom-labibb: Use disable_irq_nosync from isr

Calling the disable_irq() from irq handler might be a bad idea as
disable_irq() should wait for handlers to run. I don't see why
this wouldn't deadlock in wait_event waiting for the threaded
handler to complete.

Use disable_irq_nosync() instead.

Fixes: 390af53e04114 ("regulator: qcom-labibb: Implement short-circuit and over-current IRQs")

Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
---
This fix is done purely based on code reading. No testing is done.

I don't have the HW (and even if I did I might have hard time producing
these errors) I have not tested this and I am unsure if my code-reading
is correct => I would _really_ appreciate second opinion and/or testing

 drivers/regulator/qcom-labibb-regulator.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/regulator/qcom-labibb-regulator.c b/drivers/regulator/qcom-labibb-regulator.c
index 5ac4566f9b7f..40e92670e307 100644
--- a/drivers/regulator/qcom-labibb-regulator.c
+++ b/drivers/regulator/qcom-labibb-regulator.c
@@ -283,7 +283,7 @@ static irqreturn_t qcom_labibb_ocp_isr(int irq, void *chip)
 	 * Disable the interrupt temporarily, or it will fire continuously;
 	 * we will re-enable it in the recovery worker function.
 	 */
-	disable_irq(irq);
+	disable_irq_nosync(irq);
 
 	/* Warn the user for overcurrent */
 	dev_warn(vreg->dev, "Over-Current interrupt fired!\n");
@@ -536,7 +536,7 @@ static irqreturn_t qcom_labibb_sc_isr(int irq, void *chip)
 	 * Disable the interrupt temporarily, or it will fire continuously;
 	 * we will re-enable it in the recovery worker function.
 	 */
-	disable_irq(irq);
+	disable_irq_nosync(irq);
 
 	/* Signal out of regulation event to drivers */
 	regulator_notifier_call_chain(vreg->rdev,
-- 
2.25.4


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]