Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [PATCH v2] hwmon: acpi_power_meter: Use acpi_bus_get_acpi_device() | Date | Wed, 13 Oct 2021 18:04:09 +0200 |
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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> ---
-> v2: Resend with a different From and S-o-b address and with R-by from Andy. No other changes.
--- drivers/acpi/scan.c | 1 + drivers/hwmon/acpi_power_meter.c | 13 +++++-------- 2 files changed, 6 insertions(+), 8 deletions(-)
Index: linux-pm/drivers/hwmon/acpi_power_meter.c =================================================================== --- linux-pm.orig/drivers/hwmon/acpi_power_meter.c +++ linux-pm/drivers/hwmon/acpi_power_meter.c @@ -535,7 +535,7 @@ static void remove_domain_devices(struct 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 ac 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; } } Index: linux-pm/drivers/acpi/scan.c =================================================================== --- linux-pm.orig/drivers/acpi/scan.c +++ linux-pm/drivers/acpi/scan.c @@ -608,6 +608,7 @@ struct acpi_device *acpi_bus_get_acpi_de { 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) {
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