Subject: Re: [PATCH v3 02/13] driver core: Enable suppliers to implement fine grained sync_state support

From: "Danilo Krummrich" <[email-masked]>
Date: Fri, 08 May 2026 20:23:17 +0200

On Fri May 8, 2026 at 2:38 PM CEST, Ulf Hansson wrote:
> diff --git a/drivers/base/base.h b/drivers/base/base.h
> index 30b416588617..c8be24af92c3 100644
> --- a/drivers/base/base.h
> +++ b/drivers/base/base.h
> @@ -196,6 +196,24 @@ static inline void dev_sync_state(struct device *dev)
>  		dev->driver->sync_state(dev);
>  }
>  
> +static inline bool dev_has_queue_sync_state(struct device *dev)
> +{
> +	struct device_driver *drv;
> +
> +	if (!dev)
> +		return false;
> +	drv = READ_ONCE(dev->driver);
> +	if (drv && drv->queue_sync_state)
> +		return true;
> +	return false;
> +}
> +
> +static inline void dev_queue_sync_state(struct device *dev)
> +{

Let's add device_lock_assert(dev), as this function requires it to be held.

> +	if (dev->driver && dev->driver->queue_sync_state)
> +		dev->driver->queue_sync_state(dev);
> +}

<snip>

> @@ -1175,6 +1188,25 @@ static void device_links_flush_sync_list(struct list_head *list,
>  
>  		put_device(dev);
>  	}
> +
> +	if (!q_list)
> +		return;
> +
> +	list_for_each_entry_safe(dev, tmp, q_list, links.queue_sync) {
> +		list_del_init(&dev->links.queue_sync);

Hm...this is called without the device_links_write_lock() held, so this looks
like this could this race with the list_del_init() from
device_links_driver_cleanup() and create an infinite loop.

(The other list iterator above might have the same issue.)

> +
> +		if (dev != dont_lock_dev)

This is pre-existing, but I think it would be good to add a device_lock_assert()
call for this as well.

> +			device_lock(dev);
> +
> +		device_links_write_lock();
> +		dev_queue_sync_state(dev);
> +		device_links_write_unlock();
> +
> +		if (dev != dont_lock_dev)
> +			device_unlock(dev);
> +
> +		put_device(dev);
> +	}
>  }