Re:Re: [PATCH v3] powerpc:85xx: Add missing of_node_put() in sgy_cst1000

From: Liang He
Date: Fri Jun 17 2022 - 01:51:54 EST




At 2022-06-17 13:37:12, "Christophe JAILLET" <christophe.jaillet@xxxxxxxxxx> wrote:
>Le 17/06/2022 à 07:22, Liang He a écrit :
>> In gpio_halt_probe(), of_find_matching_node() will return a node
>> pointer with refcount incremented. We should use of_node_put() in
>> fail path or when it is not used anymore.
>>
>> Signed-off-by: Liang He <windhl@xxxxxxx>
>> ---
>> arch/powerpc/platforms/85xx/sgy_cts1000.c | 39 +++++++++++++++--------
>> 1 file changed, 25 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/85xx/sgy_cts1000.c b/arch/powerpc/platforms/85xx/sgy_cts1000.c
>> index 98ae64075193..a8690fc552cf 100644
>> --- a/arch/powerpc/platforms/85xx/sgy_cts1000.c
>> +++ b/arch/powerpc/platforms/85xx/sgy_cts1000.c
>> @@ -71,33 +71,39 @@ static int gpio_halt_probe(struct platform_device *pdev)
>> {
>> enum of_gpio_flags flags;
>> struct device_node *node = pdev->dev.of_node;
>> + struct device_node *child_node;
>> int gpio, err, irq;
>> int trigger;
>> + int ret;
>>
>> if (!node)
>> return -ENODEV;
>>
>> /* If there's no matching child, this isn't really an error */
>> - halt_node = of_find_matching_node(node, child_match);
>> - if (!halt_node)
>> + child_node = of_find_matching_node(node, child_match);
>> + if (!child_node)
>> return 0;
>>
>> /* Technically we could just read the first one, but punish
>> * DT writers for invalid form. */
>> - if (of_gpio_count(halt_node) != 1)
>> - return -EINVAL;
>> + if (of_gpio_count(child_node) != 1) {
>> + ret = -EINVAL;
>> + goto err_put;
>> + }
>>
>> /* Get the gpio number relative to the dynamic base. */
>> - gpio = of_get_gpio_flags(halt_node, 0, &flags);
>> - if (!gpio_is_valid(gpio))
>> - return -EINVAL;
>> + gpio = of_get_gpio_flags(child_node, 0, &flags);
>> + if (!gpio_is_valid(gpio)) {
>> + ret = -EINVAL;
>> + gotot err_put;
>> + }
>>
>> err = gpio_request(gpio, "gpio-halt");
>> if (err) {
>> printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",
>> gpio);
>> - halt_node = NULL;
>> - return err;
>> + ret = err;
>
>Sorry for not seeing and asking before, but why do you need 'ret'?
>Can't you use the existing 'err' in place in this whole patch?
>

Thanks, CJ.

Your advice is good and I have not noticed the 'err'.

>> + goto err_put;
>> }
>>
>> trigger = (flags == OF_GPIO_ACTIVE_LOW);
>> @@ -105,15 +111,15 @@ static int gpio_halt_probe(struct platform_device *pdev)
>> gpio_direction_output(gpio, !trigger);
>>
>> /* Now get the IRQ which tells us when the power button is hit */
>> - irq = irq_of_parse_and_map(halt_node, 0);
>> + irq = irq_of_parse_and_map(child_node, 0);
>> err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |
>> - IRQF_TRIGGER_FALLING, "gpio-halt", halt_node);
>> + IRQF_TRIGGER_FALLING, "gpio-halt", child_node);
>> if (err) {
>> printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "
>> "GPIO %d.\n", irq, gpio);
>> gpio_free(gpio);
>> - halt_node = NULL;
>> - return err;
>> + ret = err;
>> + goto err_put;
>> }
>>
>> /* Register our halt function */
>> @@ -122,8 +128,12 @@ static int gpio_halt_probe(struct platform_device *pdev)
>>
>> printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"
>> " irq).\n", gpio, trigger, irq);
>> + ret = 0;
>> + halt_node = of_node_get(child_node);
>
>LGTM, but my preferred style would be:
> halt_node = child_node;
> return 0;
>I'm not a maintainer, so this is just my opinion and it is mostly a
>mater of taste.
>
>CJ

Thanks, CJ.

Now, I also prefer this style and I will use it.

>
>>
>> - return 0;
>> +err_put:
>> + of_node_put(child_node);
>> + return ret;
>> }
>>
>> static int gpio_halt_remove(struct platform_device *pdev)
>> @@ -139,6 +149,7 @@ static int gpio_halt_remove(struct platform_device *pdev)
>>
>> gpio_free(gpio);
>>
>> + of_node_put(halt_node);
>> halt_node = NULL;
>> }
>>