[PATCH 1/2] perf/arm_dmc620: Fix hotplug callback leak in dmc620_pmu_init()

[Punit Agrawal]

Shang XiaoJing <shangxiaojing at huawei.com> writes:

> dmc620_pmu_init() won't remove the callback added by
> cpuhp_setup_state_multi() when platform_driver_register() failed. Remove
> the callback by cpuhp_remove_multi_state() in fail path.
>
> Similar to the handling of arm_ccn_init() in commit 26242b330093 ("bus:
> arm-ccn: Prevent hotplug callback leak")
>
> Fixes: 53c218da220c ("driver/perf: Add PMU driver for the ARM DMC-620 memory controller")
> Signed-off-by: Shang XiaoJing <shangxiaojing at huawei.com>
> ---
>  drivers/perf/arm_dmc620_pmu.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c
> index 280a6ae3e27c..d07054a05861 100644
> --- a/drivers/perf/arm_dmc620_pmu.c
> +++ b/drivers/perf/arm_dmc620_pmu.c
> @@ -725,6 +725,8 @@ static struct platform_driver dmc620_pmu_driver = {
>  
>  static int __init dmc620_pmu_init(void)
>  {
> +	int ret;
> +
>  	cpuhp_state_num = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
>  				      DMC620_DRVNAME,
>  				      NULL,
> @@ -732,7 +734,13 @@ static int __init dmc620_pmu_init(void)
>  	if (cpuhp_state_num < 0)
>  		return cpuhp_state_num;
>  
> -	return platform_driver_register(&dmc620_pmu_driver);
> +	ret = platform_driver_register(&dmc620_pmu_driver);
> +	if (ret) {
> +		cpuhp_remove_multi_state(cpuhp_state_num);
> +		return ret;
> +	}
> +
> +	return 0;

Nit: There's no need for two separate returns. Just return "ret" at the
bottom of the function.

With the change,

Reviewed-by: Punit Agrawal <punit.agrawal at bytedance.com>.