Re: [PATCH v2] perf/smmuv3: Add MODULE_ALIAS for module auto loading

[Liang Li]

On 2023-08-14 21:16, Yicong Yang <yangyicong@xxxxxxxxxx> wrote:
> From: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
> 
> On my ACPI based arm64 server, if the SMMUv3 PMU is configured as
> module it won't be loaded automatically after booting even if the
> device has already been scanned and added. It's because the module
> lacks a platform alias, the uevent mechanism and userspace tools
> like udevd make use of this to find the target driver module of the
> device. This patch adds the missing platform alias of the module,
> then module will be loaded automatically if device exists.
> 
> Before this patch:
> [root@localhost tmp]# modinfo arm_smmuv3_pmu | grep alias
> alias:          of:N*T*Carm,smmu-v3-pmcgC*
> alias:          of:N*T*Carm,smmu-v3-pmcg
> 
> After this patch:
> [root@localhost tmp]# modinfo arm_smmuv3_pmu | grep alias
> alias:          platform:arm-smmu-v3-pmcg
> alias:          of:N*T*Carm,smmu-v3-pmcgC*
> alias:          of:N*T*Carm,smmu-v3-pmcg
> 
> Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
> ---
> Change since v1:
> - Further illustrate the issues and how to fix this
> - Use MODULE_ALIAS instead of MODULE_DEVICE_TABLE
> Link: https://lore.kernel.org/all/20230807122233.28563-1-yangyicong@xxxxxxxxxx/
> 
>  drivers/perf/arm_smmuv3_pmu.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
> index 25a269d431e4..4c32b6dbfe76 100644
> --- a/drivers/perf/arm_smmuv3_pmu.c
> +++ b/drivers/perf/arm_smmuv3_pmu.c
> @@ -984,6 +984,7 @@ static void __exit arm_smmu_pmu_exit(void)
>  
>  module_exit(arm_smmu_pmu_exit);
>  
> +MODULE_ALIAS("platform:arm-smmu-v3-pmcg");
>  MODULE_DESCRIPTION("PMU driver for ARM SMMUv3 Performance Monitors Extension");
>  MODULE_AUTHOR("Neil Leeder <nleeder@xxxxxxxxxxxxxx>");
>  MODULE_AUTHOR("Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>");
> -- 
> 2.24.0

Looks good to me. :) Thanks.

Regards.
Liang Li