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Date:   Wed, 13 Oct 2021 18:09:10 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     Alex Williamson <alex.williamson@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>, kvm@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>,
        "Tian, Kevin" <kevin.tian@intel.com>, Liu Yi L <yi.l.liu@intel.com>
Subject: Re: [PATCH v2 3/5] vfio: Don't leak a group reference if the group
 already exists
Message-ID: <20211013160910.GC1327@lst.de>
References: <0-v2-fd9627d27b2b+26c-vfio_group_cdev_jgg@nvidia.com> <3-v2-fd9627d27b2b+26c-vfio_group_cdev_jgg@nvidia.com>
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> @@ -775,12 +776,7 @@ static struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
>  	if (group)
>  		goto out_put;
>  
> -	/* a newly created vfio_group keeps the reference. */
>  	group = vfio_create_group(iommu_group, VFIO_IOMMU);
> -	if (IS_ERR(group))
> -		goto out_put;
> -	return group;
> -
>  out_put:
>  	iommu_group_put(iommu_group);
>  	return group;

I'd simplify this down to:

	group = vfio_group_get_from_iommu(iommu_group);
	if (!group)
		group = vfio_create_group(iommu_group, VFIO_IOMMU);

but otherwise this looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>