[PATCH] arm/mach: Hold reference returned by of_find_xxx APIs

[Liang He]

At 2022-06-28 11:59:45, "Tony Lindgren" <tony at atomide.com> wrote:
>* Liang He <windhl at 126.com> [220621 12:14]:
>> diff --git a/arch/arm/mach-omap2/pmic-cpcap.c b/arch/arm/mach-omap2/pmic-cpcap.c
>> index 668dc84fd31e..a7368d657aa8 100644
>> --- a/arch/arm/mach-omap2/pmic-cpcap.c
>> +++ b/arch/arm/mach-omap2/pmic-cpcap.c
>> @@ -238,8 +238,11 @@ static struct omap_voltdm_pmic omap4_fan_iva = {
>>  int __init omap4_cpcap_init(void)
>>  {
>>  	struct voltagedomain *voltdm;
>> +	struct device_node *np;
>>  
>> -	if (!of_find_compatible_node(NULL, NULL, "motorola,cpcap"))
>> +	np = of_find_compatible_node(NULL, NULL, "motorola,cpcap");
>> +	of_node_put(np);
>> +	if (!np)
>>  		return -ENODEV;
>
>Hmm so here you are checking for !np after of_node_put()?

Hi, Tony.

Thanks very much for your effort to review my code.

I just wanted to use this 'check-after-put' coding style to keep consistent with
existing style. 

But based on the disccussion with Greg KH, yesterday, I am now preparing 'check-then-put' 
coding style patch.

Link: 
https://lore.kernel.org/all/1bed06e5.43da.181a5bac7e5.Coremail.windhl@126.com/

>
>> diff --git a/arch/arm/mach-tegra/irq.c b/arch/arm/mach-tegra/irq.c
>> index 4e1ee70b2a3f..2aeac041bcb9 100644
>> --- a/arch/arm/mach-tegra/irq.c
>> +++ b/arch/arm/mach-tegra/irq.c
>> @@ -88,7 +88,11 @@ static const struct of_device_id tegra_ictlr_match[] __initconst = {
>>  
>>  void __init tegra_init_irq(void)
>>  {
>> -	if (WARN_ON(!of_find_matching_node(NULL, tegra_ictlr_match)))
>> +	struct device_node *np;
>> +
>> +	np = of_find_matching_node(NULL, tegra_ictlr_match);
>> +	of_node_put(np);
>> +	if (WARN_ON(!np))
>>  		pr_warn("Outdated DT detected, suspend/resume will NOT work\n");
>>  
>>  	tegra114_gic_cpu_pm_registration();
>
>Here too.
>
>Regards,
>
>Tony

Thanks again, Tony.

I will send a new 'check-and-put' patch soon.

Liang