perf: Allow a PMU to have a parent

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.

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>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20230526095824.16336-2-Jonathan.Cameron@huawei.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index d5628a7..b99db1e 100644 (file)
--- 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 db016e4..285cf6c 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11379,6 +11379,7 @@ 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);