Re: [PATCH 05/10] driver core: Export device_driver_attach()

[Christoph Hellwig <hch@infradead.org>]

On Mon, Jun 07, 2021 at 09:55:47PM -0300, Jason Gunthorpe wrote:
> This is intended as a replacement API for device_bind_driver(). It has at
> least the following benefits:
> 
> - Internal locking. Few of the users of device_bind_driver() follow the
>   locking rules
> 
> - Calls device driver probe() internally. Notably this means that devm
>   support for probe works correctly as probe() error will call
>   devres_release_all()
> 
> - struct device_driver -> dev_groups is supported
> 
> - Simplified calling convention, no need to manually call probe().

Btw, it would be nice to convert at least one existing user of
device_bind_driver to show this.  Also maybe Cc all maintainers of
subsystems using device_bind_driver so that they get a headsup and
maybe quickly move over?

> @@ -1077,6 +1079,7 @@ int device_driver_attach(struct device_driver *drv, struct device *dev)
>  		return -EAGAIN;
>  	return ret;
>  }
> +EXPORT_SYMBOL_GPL(device_driver_attach);

Ok, this means my earlier suggestions of a locked driver_probe_device
helper needs a different name as we really don't want to expose flags
and always return -EAGAIN here.  So maybe rename driver_probe_device
to __driver_probe_device, have a driver_probe_device around it that
does the locking and keep device_driver_attach for the newly exported
API.

The kerneldoc for device_driver_attach is pretty sparse, it might want a
little brushup as well.