Re: [PATCH v2] ARM: s3c: irq-s3c24xx: Fix return value check for s3c24xx_init_intc()

[Jackie Liu <liu.yun@linux.dev>]

Hi, krzysztof. Any suggestion?

--
BR, Jackie Liu

在 2021/9/1 下午8:35, Jackie Liu 写道:
> From: Jackie Liu <liuyun01@kylinos.cn>
> 
> The s3c24xx_init_intc() returns an error pointer upon failure, not NULL.
> let's add an error pointer check in s3c24xx_handle_irq.
> 
> s3c_intc[0] is not NULL or ERR, we can simplify the code.
> 
> Fixes: 1f629b7a3ced ("ARM: S3C24XX: transform irq handling into a declarative form")
> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
> ---
>   arch/arm/mach-s3c/irq-s3c24xx.c | 21 +++++++++++++++++----
>   1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/mach-s3c/irq-s3c24xx.c b/arch/arm/mach-s3c/irq-s3c24xx.c
> index 0c631c14a817..df471d322493 100644
> --- a/arch/arm/mach-s3c/irq-s3c24xx.c
> +++ b/arch/arm/mach-s3c/irq-s3c24xx.c
> @@ -362,11 +362,24 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
>   static asmlinkage void __exception_irq_entry s3c24xx_handle_irq(struct pt_regs *regs)
>   {
>   	do {
> -		if (likely(s3c_intc[0]))
> -			if (s3c24xx_handle_intc(s3c_intc[0], regs, 0))
> -				continue;
> +		/* For platform based machines, neither ERR nor NULL can happen here.
> +		 * The s3c24xx_handle_irq() will be set as IRQ handler iff this succeeds:
> +		 *
> +		 *    s3c_intc[0] = s3c24xx_init_intc()
> +		 *
> +		 * If this fails, the next calls to s3c24xx_init_intc() won't be executed.
> +		 *
> +		 * For DT machine, s3c_init_intc_of() could set the IRQ handler without
> +		 * setting s3c_intc[0] only if it was called with num_ctrl=0. There is no
> +		 * such code path, so again the s3c_intc[0] will have a valid pointer if
> +		 * set_handle_irq() is called.
> +		 *
> +		 * Therefore in s3c24xx_handle_irq(), the s3c_intc[0] is always something.
> +		 */
> +		if (s3c24xx_handle_intc(s3c_intc[0], regs, 0))
> +			continue;
>   
> -		if (s3c_intc[2])
> +		if (!IS_ERR_OR_NULL(s3c_intc[2]))
>   			if (s3c24xx_handle_intc(s3c_intc[2], regs, 64))
>   				continue;
>   
>