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hwmon: (acpi_power_meter) Use acpi_bus_get_acpi_device()

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In read_domain_devices(), acpi_bus_get_device() is called to obtain
the ACPI device object attached to the given ACPI handle and
subsequently that object is passed to get_device() for reference
counting, but there is a window between the acpi_bus_get_device()
and get_device() calls in which the ACPI device object in question
may go away.

To address this issue, make read_domain_devices() use
acpi_bus_get_acpi_device() to reference count and return the given
ACPI device object in one go and export that function to modules.

While at it, also make read_domain_devices() and
remove_domain_devices() use acpi_dev_put() instead of calling
put_device() directly on the ACPI device objects returned by
acpi_bus_get_acpi_device().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/11871063.O9o76ZdvQC@kreacher
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Rafael J. Wysocki 2021-10-13 18:04:09 +02:00 committed by Guenter Roeck
parent b1986c8e31
commit 2c59a32d12
2 changed files with 6 additions and 8 deletions
drivers
acpi
scan.c
hwmon
acpi_power_meter.c

1
drivers/acpi/scan.c
View File

@ -608,6 +608,7 @@ struct acpi_device *acpi_bus_get_acpi_device(acpi_handle handle)
{
return handle_to_device(handle, get_acpi_device);
}
EXPORT_SYMBOL_GPL(acpi_bus_get_acpi_device);
static struct acpi_device_bus_id *acpi_device_bus_id_match(const char *dev_id)
{

13
drivers/hwmon/acpi_power_meter.c
View File

@ -535,7 +535,7 @@ static void remove_domain_devices(struct acpi_power_meter_resource *resource)
sysfs_remove_link(resource->holders_dir,
kobject_name(&obj->dev.kobj));
put_device(&obj->dev);
acpi_dev_put(obj);
}
kfree(resource->domain_devices);
@ -597,18 +597,15 @@ static int read_domain_devices(struct acpi_power_meter_resource *resource)
continue;
/* Create a symlink to domain objects */
resource->domain_devices[i] = NULL;
if (acpi_bus_get_device(element->reference.handle,
&resource->domain_devices[i]))
obj = acpi_bus_get_acpi_device(element->reference.handle);
resource->domain_devices[i] = obj;
if (!obj)
continue;
obj = resource->domain_devices[i];
get_device(&obj->dev);
res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
kobject_name(&obj->dev.kobj));
if (res) {
put_device(&obj->dev);
acpi_dev_put(obj);
resource->domain_devices[i] = NULL;
}
}