linux-kernel - Re: [PATCH] rqchip/stm32: Remove unneeded call to kfree

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Message-ID: <1d9aa4be-4da2-b532-4787-c98869c0bd9d@arm.com>
Date:   Mon, 22 Jul 2019 11:26:09 +0100
From:   Steven Price <steven.price@....com>
To:     Hariprasad Kelam <hariprasad.kelam@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        linux-kernel@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] rqchip/stm32: Remove unneeded call to kfree

On 19/07/2019 19:46, Hariprasad Kelam wrote:
> Memory allocated by devm_ alloc will be freed upon device detachment. So
> we may not require free memory.
> 
> Signed-off-by: Hariprasad Kelam <hariprasad.kelam@...il.com>
> ---
>  drivers/irqchip/irq-stm32-exti.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/irqchip/irq-stm32-exti.c b/drivers/irqchip/irq-stm32-exti.c
> index e00f2fa..46ec0af 100644
> --- a/drivers/irqchip/irq-stm32-exti.c
> +++ b/drivers/irqchip/irq-stm32-exti.c
> @@ -779,8 +779,6 @@ static int __init stm32_exti_init(const struct stm32_exti_drv_data *drv_data,
>  	irq_domain_remove(domain);
>  out_unmap:
>  	iounmap(host_data->base);
> -	kfree(host_data->chips_data);
> -	kfree(host_data);

In the commit this is based on these variables are not allocated using a
devm_ alloc function:

$ git show e00f2fa | grep -A12 *stm32_exti_host_init
> stm32_exti_host_data *stm32_exti_host_init(const struct stm32_exti_drv_data *dd,
> 					   struct device_node *node)
> {
> 	struct stm32_exti_host_data *host_data;
> 
> 	host_data = kzalloc(sizeof(*host_data), GFP_KERNEL);
> 	if (!host_data)
> 		return NULL;
> 
> 	host_data->drv_data = dd;
> 	host_data->chips_data = kcalloc(dd->bank_nr,
> 					sizeof(struct stm32_exti_chip_data),
> 					GFP_KERNEL);
The function stm32_exti_probe *does* use devm_k?alloc, so perhaps you
were getting confused with that?

Steve

>  	return ret;
>  }
>  
>