RE: [PATCH 2/3] drivers:hv Convert VMBus and its descendants to PnP

[Jake Oshins]

> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@xxxxxxxxxx]
> Sent: Wednesday, February 18, 2015 2:24 AM
> To: Jake Oshins
> Cc: rafael.j.wysocki@xxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; KY Srinivasan;
> linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx;
> apw@xxxxxxxxxxxxx; vkuznets@xxxxxxxxxx
> Subject: Re: [PATCH 2/3] drivers:hv Convert VMBus and its descendants to PnP
> 
> On Tue, Feb 17, 2015 at 11:41:50AM -0800, Jake Oshins wrote:
> >
> > +	ret = pnp_add_descendant(child_device_obj->pnp_dev);
> >  	if (ret)
> > +		goto register_exit;
> > +
> > +	added = TRUE;
> > +
> > +	ret = pnp_activate_dev(child_device_obj->pnp_dev);
> > +
> > +register_exit:
> > +
> > +	if (ret) {
> > +		if (added)
> > +			pnp_remove_descendant(child_device_obj->pnp_dev);
> > +		free_pnp_descendant(child_device_obj->pnp_dev);
> >  		pr_err("Unable to register child device\n");
> > -	else
> > +	} else
> >  		pr_debug("child device %s registered\n",
> > -			dev_name(&child_device_obj->device));
> > +			 dev_name(&child_device_obj->pnp_dev->dev));
> >
> >  	return ret;
> >  }
> 
> This error handling is horribly ugly and has a bug.  Please, read my
> essay on how to do error handling properly.
> 
> https://plus.google.com/106378716002406849458/posts/dnanfhQ4mHQ
> 
> 1) Don't do "One Err" style error handling.
> 2) Don't twist the success path and the error paths together.
> 3) Don't use the "added" variable.
> 4) Don't initialize "ret" at the start of the function.
> 5) Don't forget to undo pnp_descendant_memory_option()
> 
> It should look something like:
> 
> 	return 0;
> 
> err_remove_desc:
> 	pnp_remove_descendant(child_device_obj->pnp_dev);
> err_remove_option:
> 	if (bytes)
> 		remove_whatever();
> err_free_desc:
> 	free_pnp_descendant(child_device_obj->pnp_dev);
> 
> 	return ret;
> 
> regards,
> dan carpenter


Will do.  Thanks for the review.

-- Jake Oshins

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