drivers/acpi/scan.c: inconsequent NULL handling

The Coverity checker found the following:

<-- snip -->

static int
acpi_bus_match (
struct acpi_device *device,
struct acpi_driver *driver)

{
        if (driver && driver->ops.match)
                return driver->ops.match(device, driver);
        return acpi_match_ids(device, driver->ids);
}

<-- snip -->

Either driver can be NULL, in which case the driver->ids is a possible NULL pointer reference, or it can't, in which case the check whether it's NULL is superfluous.

cu
Adrian

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

Follow the mon^Wcall tree.

drivers/acpi/scan.c:478: * acpi_bus_match drivers/acpi/scan.c:484:acpi_bus_match(struct acpi_device *device, struct acpi_driver *driver)
drivers/acpi/scan.c:564: if (!acpi_bus_match(dev, drv)) {
drivers/acpi/scan.c:682: if (!acpi_bus_match(device, driver)) {

1. acpi_bus_match()

Second arg is passed without changes.

	acpi_driver_attach()
		acpi_bus_register_driver()

	  ===>	if (!driver) <===
			return_VALUE(-EINVAL);

		spin_lock(&acpi_device_lock);
		list_add_tail(&driver->node, &acpi_bus_drivers);
		spin_unlock(&acpi_device_lock);
		count = acpi_driver_attach(driver);

2. acpi_bus_match()

	acpi_bus_find_driver()

		atomic_inc(&driver->references);
			    ^^^^^^^^
                spin_unlock(&acpi_device_lock);
		if (!acpi_bus_match(device, driver)) {

Looks like it can't.