Re: [PATCH 2/5] driver core: separate function to shutdown one device

Bart Van Assche
2026-03-11T18:00:27Z

On 3/11/26 10:12 AM, David Jeffery wrote:
> +static void shutdown_one_device(struct device *dev)
> +{
> + /* hold lock to avoid race with probe/release */
> + if (dev->parent && dev->bus && dev->bus->need_parent_lock)
> + device_lock(dev->parent);
> + device_lock(dev);
> +
> + /* Don't allow any more runtime suspends */
> + pm_runtime_get_noresume(dev);
> + pm_runtime_barrier(dev);
> +
> + if (dev->class && dev->class->shutdown_pre) {
> + if (initcall_debug)
> + dev_info(dev, "shutdown_pre\n");
> + dev->class->shutdown_pre(dev);
> + }
> + if (dev->bus && dev->bus->shutdown) {
> + if (initcall_debug)
> + dev_info(dev, "shutdown\n");
> + dev->bus->shutdown(dev);
> + } else if (dev->driver && dev->driver->shutdown) {
> + if (initcall_debug)
> + dev_info(dev, "shutdown\n");
> + dev->driver->shutdown(dev);
> + }
> +
> + device_unlock(dev);
> + if (dev->parent && dev->bus && dev->bus->need_parent_lock)
> + device_unlock(dev->parent);
> +
> + put_device(dev->parent);
> + put_device(dev);
> +}

Please keep the following code in the caller:

if (dev->parent && dev->bus && dev->bus->need_parent_lock)
device_lock(dev->parent);

if (dev->parent && dev->bus && dev->bus->need_parent_lock)
device_unlock(dev->parent);

put_device(dev->parent);
put_device(dev);

Additionally, please make sure that the caller is made compatible with
lock context analysis (see also
https://lore.kernel.org/all/20250206181711.1902989-1-elver@google.com/).
All that is required to make this code compatible with lock context
analysis is to organize it as follows:

if (dev->parent && dev->bus && dev->bus->need_parent_lock) {
device_lock(dev->parent);
shutdown_one_device(dev);
device_unlock(dev->parent);
} else {
shutdown_one_device(dev);
}

Thanks,

Bart.