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Date:   Fri, 14 Apr 2023 10:20:39 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc:     Liang Kan <kan.liang@linux.intel.com>, linux-cxl@vger.kernel.org,
        mark.rutland@arm.com, will@kernel.org, mingo@redhat.com,
        acme@kernel.org, dan.j.williams@intel.com, linuxarm@huawei.com,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        Davidlohr Bueso <dave@stgolabs.net>,
        Dave Jiang <dave.jiang@intel.com>
Subject: Re: [PATCH v6 1/5] perf: Allow a PMU to have a parent
Message-ID: <20230414082039.GT4253@hirez.programming.kicks-ass.net>
References: <20230413142617.15995-1-Jonathan.Cameron@huawei.com>
 <20230413142617.15995-2-Jonathan.Cameron@huawei.com>
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In-Reply-To: <20230413142617.15995-2-Jonathan.Cameron@huawei.com>
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On Thu, Apr 13, 2023 at 03:26:13PM +0100, Jonathan Cameron wrote:
> Some PMUs have well defined parents such as PCI devices.
> As the device_initialize() and device_add() are all within
> pmu_dev_alloc() which is called from perf_pmu_register()
> there is no opportunity to set the parent from within a driver.
> 
> Add a struct device *parent field to struct pmu and use that
> to set the parent.
> 
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> ---
> v6: No change
> v5: Move to head of series as may merge as part of:
> https://lore.kernel.org/all/20230404134225.13408-1-Jonathan.Cameron@huawei.com/
> ---
>  include/linux/perf_event.h | 1 +
>  kernel/events/core.c       | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index d5628a7b5eaa..b99db1eda72c 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -303,6 +303,7 @@ struct pmu {
>  
>  	struct module			*module;
>  	struct device			*dev;
> +	struct device			*parent;
>  	const struct attribute_group	**attr_groups;
>  	const struct attribute_group	**attr_update;
>  	const char			*name;
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 435815d3be3f..32079a332480 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -11367,6 +11367,7 @@ static int pmu_dev_alloc(struct pmu *pmu)
>  
>  	dev_set_drvdata(pmu->dev, pmu);
>  	pmu->dev->bus = &pmu_bus;
> +	pmu->dev->parent = pmu->parent;
>  	pmu->dev->release = pmu_dev_release;
>  
>  	ret = dev_set_name(pmu->dev, "%s", pmu->name);
> -- 
> 2.37.2
>