RE: [PATCH v3 2/2] kvm/vfio: avoid bouncing the mutex when adding and deleting groups

[Tian, Kevin]

> From: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> Sent: Saturday, July 15, 2023 6:46 AM
>
> @@ -165,30 +161,26 @@ static int kvm_vfio_group_add(struct kvm_device
> *dev, unsigned int fd)
>  	list_for_each_entry(kvg, &kv->group_list, node) {
>  		if (kvg->file == filp) {
>  			ret = -EEXIST;
> -			goto err_unlock;
> +			goto out_unlock;
>  		}
>  	}
> 
>  	kvg = kzalloc(sizeof(*kvg), GFP_KERNEL_ACCOUNT);
>  	if (!kvg) {
>  		ret = -ENOMEM;
> -		goto err_unlock;
> +		goto out_unlock;
>  	}
> 
> -	kvg->file = filp;
> +	kvg->file = get_file(filp);

Why is another reference required here?