linux-kernel - Re: [PATCH v3 2/2] irqchip/aspeed-intc: Add support for AST27XX INTC

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Message-ID: <0b995a34-28c4-4ba6-8ad2-e8413c6a63f5@web.de>
Date: Fri, 11 Oct 2024 17:34:02 +0200
From: Markus Elfring <Markus.Elfring@....de>
To: Kevin Chen <kevin_chen@...eedtech.com>, linux-aspeed@...ts.ozlabs.org,
 linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
 Andrew Jeffery <andrew@...econstruct.com.au>,
 Conor Dooley <conor+dt@...nel.org>, Joel Stanley <joel@....id.au>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Rob Herring <robh@...nel.org>,
 Thomas Gleixner <tglx@...utronix.de>, BMC-SW <BMC-SW@...eedtech.com>
Cc: LKML <linux-kernel@...r.kernel.org>, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v3 2/2] irqchip/aspeed-intc: Add support for AST27XX INTC

>> …
>>> +++ b/drivers/irqchip/irq-aspeed-intc.c
>>> @@ -0,0 +1,139 @@
>> …
>>> +static void aspeed_intc_ic_irq_handler(struct irq_desc *desc)
>> +{
>>> +	struct aspeed_intc_ic *intc_ic = irq_desc_get_handler_data(desc);
>>> +	struct irq_chip *chip = irq_desc_get_chip(desc);
>>> +	unsigned long bit, status;
>>
>> I suggest to reduce the scopes for three local variables.
> May I check the scopes of bit and status usage?
> Variables of bit and status are used in for_each_set_bit.
> How could I reduce the scopes?

I propose to move selected variable definitions into corresponding compound statements
(by using extra curly brackets).
https://refactoring.com/catalog/reduceScopeOfVariable.html


>> Would you become interested to collaborate with another scoped guard for
>> this programming interface?
>> https://elixir.bootlin.com/linux/v6.12-rc2/source/include/linux/irqchip/chained
>> _irq.h#L13
>
> Maybe like the change in the following?
>
> diff --git a/drivers/irqchip/irq-aspeed-intc.c b/drivers/irqchip/irq-aspeed-intc.c
> index ef1c095ad09e..54d1881c56c6 100644
> --- a/drivers/irqchip/irq-aspeed-intc.c
> +++ b/drivers/irqchip/irq-aspeed-intc.c
> @@ -32,7 +32,7 @@ static void aspeed_intc_ic_irq_handler(struct irq_desc *desc)
>         struct irq_chip *chip = irq_desc_get_chip(desc);
>         unsigned long bit, status;
>
> -       chained_irq_enter(chip, desc);
> +       guard(chained_irq)(desc);
>
>         scoped_guard(raw_spinlock, &intc_ic->gic_lock) {
>                 status = readl(intc_ic->base + INTC_INT_STATUS_REG);

Perhaps.


> @@ -41,8 +41,6 @@ static void aspeed_intc_ic_irq_handler(struct irq_desc *desc)
>                         writel(BIT(bit), intc_ic->base + INTC_INT_STATUS_REG);
>                 }
>         }
> -
> -       chained_irq_exit(chip, desc);
>  }
…

Probably, yes.


…
> +++ b/include/linux/irqchip/chained_irq.h
> @@ -38,4 +38,5 @@ static inline void chained_irq_exit(struct irq_chip *chip,
>                 chip->irq_unmask(&desc->irq_data);
>  }
>
> +DEFINE_GUARD (chained_irq, struct irq_desc * , chained_irq_exit ( _T ->irq_data.chip, _T ), chained_irq_enter (_T->irq_data.chip, _T))
…

* Such a macro call looks promising.
  Would you like to omit any space characters before open parentheses?

* Would you like to support scoped guard variants accordingly?


Regards,
Markus