Re: [PATCH 2/2] regulator: qcom-labibb: Use disable_irq_nosync from isr

[AngeloGioacchino Del Regno]

Il 02/02/21 08:37, Matti Vaittinen ha scritto:
> 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.

It didn't deadlock, but looking at it again -- oh my, I agree with you.

Reviewed-by: AngeloGioacchino Del Regno 
<angelogioacchino.delregno@xxxxxxxxxxxxxx>

> Fixes: 390af53e04114 ("regulator: qcom-labibb: Implement short-circuit and over-current IRQs")
>
> Signed-off-by: Matti Vaittinen <matti.vaittinen@xxxxxxxxxxxxxxxxx>
> ---
> 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,