linux-kernel - Re: [PATCH v2 1/2] cpuidle: riscv-sbi: Use scoped device node handling to fix missing of_node

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Message-ID: <CAAhSdy3S_QTBzCNtj8kKDpzxtoeyKWvGLtjgSTViieWimpP-JA@mail.gmail.com>
Date: Tue, 20 Aug 2024 16:26:49 +0530
From: Anup Patel <anup@...infault.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: "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>, linux-pm@...r.kernel.org, 
	linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	stable@...r.kernel.org
Subject: Re: [PATCH v2 1/2] cpuidle: riscv-sbi: Use scoped device node
 handling to fix missing of_node_put

On Tue, Aug 20, 2024 at 3:10 PM Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org> wrote:
>
> Two return statements in sbi_cpuidle_dt_init_states() did not drop the
> OF node reference count.  Solve the issue and simplify entire error
> handling with scoped/cleanup.h.
>
> Fixes: 6abf32f1d9c5 ("cpuidle: Add RISC-V SBI CPU idle driver")
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

LGTM.

Reviewed-by: Anup Patel <anup@...infault.org>

Regards,
Anup

>
> ---
>
> Changes in v2:
> 1. Re-write commit msg, because this is actually a fix.
> ---
>  drivers/cpuidle/cpuidle-riscv-sbi.c | 21 +++++++--------------
>  1 file changed, 7 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
> index a6e123dfe394..5bb3401220d2 100644
> --- a/drivers/cpuidle/cpuidle-riscv-sbi.c
> +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
> @@ -8,6 +8,7 @@
>
>  #define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt
>
> +#include <linux/cleanup.h>
>  #include <linux/cpuhotplug.h>
>  #include <linux/cpuidle.h>
>  #include <linux/cpumask.h>
> @@ -236,19 +237,16 @@ static int sbi_cpuidle_dt_init_states(struct device *dev,
>  {
>         struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
>         struct device_node *state_node;
> -       struct device_node *cpu_node;
>         u32 *states;
>         int i, ret;
>
> -       cpu_node = of_cpu_device_node_get(cpu);
> +       struct device_node *cpu_node __free(device_node) = of_cpu_device_node_get(cpu);
>         if (!cpu_node)
>                 return -ENODEV;
>
>         states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
> -       if (!states) {
> -               ret = -ENOMEM;
> -               goto fail;
> -       }
> +       if (!states)
> +               return -ENOMEM;
>
>         /* Parse SBI specific details from state DT nodes */
>         for (i = 1; i < state_count; i++) {
> @@ -264,10 +262,8 @@ static int sbi_cpuidle_dt_init_states(struct device *dev,
>
>                 pr_debug("sbi-state %#x index %d\n", states[i], i);
>         }
> -       if (i != state_count) {
> -               ret = -ENODEV;
> -               goto fail;
> -       }
> +       if (i != state_count)
> +               return -ENODEV;
>
>         /* Initialize optional data, used for the hierarchical topology. */
>         ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
> @@ -277,10 +273,7 @@ static int sbi_cpuidle_dt_init_states(struct device *dev,
>         /* Store states in the per-cpu struct. */
>         data->states = states;
>
> -fail:
> -       of_node_put(cpu_node);
> -
> -       return ret;
> +       return 0;
>  }
>
>  static void sbi_cpuidle_deinit_cpu(int cpu)
> --
> 2.43.0
>