linux-kernel - Re: [PATCH v3] cpuidle: riscv-sbi: fix device node release in early exit of for_each_possible

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Message-ID: <eee10593-eb0b-4660-80cf-3027d6a99435@ghiti.fr>
Date: Thu, 5 Dec 2024 15:40:09 +0100
From: Alexandre Ghiti <alex@...ti.fr>
To: Javier Carrasco <javier.carrasco.cruz@...il.com>,
 Anup Patel <anup@...infault.org>, "Rafael J. Wysocki" <rafael@...nel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt
 <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
 Atish Patra <atishp@...osinc.com>
Cc: Palmer Dabbelt <palmer@...osinc.com>, linux-pm@...r.kernel.org,
 linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
 Andrew Jones <ajones@...tanamicro.com>
Subject: Re: [PATCH v3] cpuidle: riscv-sbi: fix device node release in early
 exit of for_each_possible_cpu

Hi Anup,

On 16/11/2024 00:32, Javier Carrasco wrote:
> The 'np' device_node is initialized via of_cpu_device_node_get(), which
> requires explicit calls to of_node_put() when it is no longer required
> to avoid leaking the resource.
>
> Instead of adding the missing calls to of_node_put() in all execution
> paths, use the cleanup attribute for 'np' by means of the __free()
> macro, which automatically calls of_node_put() when the variable goes
> out of scope. Given that 'np' is only used within the
> for_each_possible_cpu(), reduce its scope to release the nood after
> every iteration of the loop.
>
> Fixes: 6abf32f1d9c5 ("cpuidle: Add RISC-V SBI CPU idle driver")
> Reviewed-by: Andrew Jones <ajones@...tanamicro.com>
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>
> ---
> Changes in v3:
> - Unwrap line (100 char width).
> - Link to v2: https://lore.kernel.org/r/20241031-cpuidle-riscv-sbi-cleanup-v2-1-aae62d383118@gmail.com
>
> Changes in v2:
> - Squash patches for mainline solution without intermediate steps.
> - Link to v1: https://lore.kernel.org/r/20241030-cpuidle-riscv-sbi-cleanup-v1-0-5e08a22c9409@gmail.com
> ---
>   drivers/cpuidle/cpuidle-riscv-sbi.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
> index 14462c092039..0c92a628bbd4 100644
> --- a/drivers/cpuidle/cpuidle-riscv-sbi.c
> +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
> @@ -504,12 +504,12 @@ static int sbi_cpuidle_probe(struct platform_device *pdev)
>   	int cpu, ret;
>   	struct cpuidle_driver *drv;
>   	struct cpuidle_device *dev;
> -	struct device_node *np, *pds_node;
> +	struct device_node *pds_node;
>   
>   	/* Detect OSI support based on CPU DT nodes */
>   	sbi_cpuidle_use_osi = true;
>   	for_each_possible_cpu(cpu) {
> -		np = of_cpu_device_node_get(cpu);
> +		struct device_node *np __free(device_node) = of_cpu_device_node_get(cpu);
>   		if (np &&
>   		    of_property_present(np, "power-domains") &&
>   		    of_property_present(np, "power-domain-names")) {
>
> ---
> base-commit: 744cf71b8bdfcdd77aaf58395e068b7457634b2c
> change-id: 20241029-cpuidle-riscv-sbi-cleanup-e9b3cb96e16d
>
> Best regards,


Will you make a PR for this? Or should this go through the riscv tree?

Thanks,

Alex