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From:   Jonathan Cameron <Jonathan.Cameron@huawei.com>
To:     Liang Kan <kan.liang@linux.intel.com>, <linux-cxl@vger.kernel.org>,
        <peterz@infradead.org>
CC:     <mingo@redhat.com>, <acme@kernel.org>, <mark.rutland@arm.com>,
        <will@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: [PATCH v4 2/5] perf: Allow a PMU to have a parent
Date:   Thu, 30 Mar 2023 17:45:53 +0100
Message-ID: <20230330164556.31533-3-Jonathan.Cameron@huawei.com>
In-Reply-To: <20230330164556.31533-1-Jonathan.Cameron@huawei.com>
References: <20230330164556.31533-1-Jonathan.Cameron@huawei.com>
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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>
---
v4: No change
Note that this may first merge as part of a larger series I
plan to post next week that adds parents for many of the of the
other struct pmu instances.  If so please drop this patch whilst
applying.

---
 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 fb3e436bcd4a..a84c282221f2 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