Re: [PATCH v7 02/19] iommufd: Add iommufd_group

[Baolu Lu <baolu.lu@linux.intel.com>]

On 5/16/23 8:54 PM, Jason Gunthorpe wrote:
> On Tue, May 16, 2023 at 10:43:23AM +0800, Baolu Lu wrote:
>> On 5/15/23 10:00 PM, Jason Gunthorpe wrote:
>>>    void iommufd_device_destroy(struct iommufd_object *obj)
>>>    {
>>>    	struct iommufd_device *idev =
>>>    		container_of(obj, struct iommufd_device, obj);
>>>    	iommu_device_release_dma_owner(idev->dev);
>>> -	iommu_group_put(idev->group);
>>> +	iommufd_put_group(idev->igroup);
>>>    	if (!iommufd_selftest_is_mock_dev(idev->dev))
>>>    		iommufd_ctx_put(idev->ictx);
>>>    }
>>> @@ -46,7 +154,7 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
>>>    					   struct device *dev, u32 *id)
>>>    {
>>>    	struct iommufd_device *idev;
>>> -	struct iommu_group *group;
>>> +	struct iommufd_group *igroup;
>>>    	int rc;
>>>    	/*
>>> @@ -56,9 +164,9 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
>>>    	if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY))
>>>    		return ERR_PTR(-EINVAL);
>>> -	group = iommu_group_get(dev);
>>> -	if (!group)
>>> -		return ERR_PTR(-ENODEV);
>>> +	igroup = iommufd_get_group(ictx, dev);
>>> +	if (IS_ERR(igroup))
>>> +		return ERR_CAST(igroup);
>>>    	/*
>>>    	 * For historical compat with VFIO the insecure interrupt path is
>> Hi Jason,
>>
>> Perhaps I am asking a silly question. The iommufd_group is get in
>> iommufd_device_bind(), but put in iommufd_device_destroy(). Why not put
>> it in iommufd_device_unbind()?
> It basically is like that, iommufd_device_destroy() is a helper that
> is only called by iommufd_device_unbind() through the usual
> destruction mechanism.

Oh, yes. Thank you for the explanation.

Best regards,
baolu