Re: [PATCH V2 5/8] perf/x86/intel/uncore: Factor out box setup code

["Mi, Dapeng" <dapeng1.mi@linux.intel.com>]

Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>

On 6/2/2026 1:01 AM, Zide Chen wrote:
> The PCI uncore PMU path already implements a lazy registration model:
> the PMU is registered when the first active box appears and
> unregistered when the last active box is removed.
>
> Factor this registration management into a shared helper, so the same
> code can be reused by the MSR and MMIO paths in later changes.
>
> No functional change intended.
>
> Reviewed-by: Ian Rogers <irogers@google.com>
> Signed-off-by: Zide Chen <zide.chen@intel.com>
> ---
>  arch/x86/events/intel/uncore.c | 40 ++++++++++++++++++++++++----------
>  1 file changed, 28 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
> index 6df44f69cc5b..283e41933ba7 100644
> --- a/arch/x86/events/intel/uncore.c
> +++ b/arch/x86/events/intel/uncore.c
> @@ -1148,6 +1148,29 @@ uncore_pci_find_dev_pmu(struct pci_dev *pdev, const struct pci_device_id *ids)
>  	return pmu;
>  }
>  
> +static int uncore_box_setup(struct intel_uncore_pmu *pmu,
> +			    struct intel_uncore_box *box)
> +{
> +	int ret;
> +
> +	uncore_box_init(box);
> +
> +	/* First active box registers the pmu. */
> +	if (atomic_inc_return(&pmu->activeboxes) > 1)
> +		return 0;
> +
> +	ret = uncore_pmu_register(pmu);
> +	if (ret) {
> +		atomic_dec(&pmu->activeboxes);
> +		goto err;
> +	}
> +
> +	return 0;
> +err:
> +	uncore_box_exit(box);
> +	return ret;
> +}
> +
>  /*
>   * Register the PMU for a PCI device
>   * @pdev: The PCI device.
> @@ -1173,20 +1196,13 @@ static int uncore_pci_pmu_register(struct pci_dev *pdev,
>  	box->dieid = die;
>  	box->pci_dev = pdev;
>  	box->pmu = pmu;
> -	uncore_box_init(box);
>  
> -	pmu->boxes[die] = box;
> -	if (atomic_inc_return(&pmu->activeboxes) > 1)
> -		return 0;
> -
> -	/* First active box registers the pmu */
> -	ret = uncore_pmu_register(pmu);
> -	if (ret) {
> -		atomic_dec(&pmu->activeboxes);
> -		pmu->boxes[die] = NULL;
> -		uncore_box_exit(box);
> +	ret = uncore_box_setup(pmu, box);
> +	if (!ret)
> +		pmu->boxes[die] = box;
> +	else
>  		kfree(box);
> -	}
> +
>  	return ret;
>  }
>