Re: [PATCH 09/14] iommufd: Add iommufd_device_replace()

[Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>]

On 2/25/23 8:27 AM, Jason Gunthorpe wrote:
> @@ -437,25 +517,77 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
>   		struct iommufd_ioas *ioas =
>   			container_of(pt_obj, struct iommufd_ioas, obj);
>   
> -		rc = iommufd_device_auto_get_domain(idev, ioas, pt_id);
> -		if (rc)
> +		destroy_hwpt = iommufd_device_auto_get_domain(idev, ioas, pt_id,
> +							      do_attach);
> +		if (IS_ERR(destroy_hwpt))
>   			goto out_put_pt_obj;
>   		break;
>   	}
>   	default:
> -		rc = -EINVAL;
> +		destroy_hwpt = ERR_PTR(-EINVAL);
>   		goto out_put_pt_obj;
>   	}
> +	iommufd_put_object(pt_obj);
>   
> -	refcount_inc(&idev->obj.users);
> -	rc = 0;
> +	/* This destruction has to be after we unlock everything */
> +	if (destroy_hwpt)

Should this be

	if (!IS_ERR_OR_NULL(destroy_hwpt))

?

> +		iommufd_hw_pagetable_put(idev->ictx, destroy_hwpt);
> +	return 0;
>   
>   out_put_pt_obj:
>   	iommufd_put_object(pt_obj);
> -	return rc;
> +	return PTR_ERR(destroy_hwpt);
> +}

Best regards,
baolu