Re: [v4 2/3] vfio_register_notifier: also register on the group notifier

[Jike Song <jike.song@intel.com>]

On 11/16/2016 07:11 AM, Alex Williamson wrote:
> On Tue, 15 Nov 2016 19:35:46 +0800
> Jike Song <jike.song@intel.com> wrote:
> 
>> The user of vfio_register_notifier might care about not only
>> iommu events but also vfio_group events, so also register the
>> notifier_block on vfio_group.
>>
>> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Alex Williamson <alex.williamson@redhat.com>
>> Signed-off-by: Jike Song <jike.song@intel.com>
>> ---
>>  drivers/vfio/vfio.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
>> index b149ced..2c0eedb 100644
>> --- a/drivers/vfio/vfio.c
>> +++ b/drivers/vfio/vfio.c
>> @@ -2065,6 +2065,8 @@ int vfio_register_notifier(struct device *dev, struct notifier_block *nb)
>>  	else
>>  		ret = -ENOTTY;
>>  
>> +	vfio_group_register_notifier(group, nb);
>> +
>>  	up_read(&container->group_lock);
>>  	vfio_group_try_dissolve_container(group);
>>  
>> @@ -2102,6 +2104,8 @@ int vfio_unregister_notifier(struct device *dev, struct notifier_block *nb)
>>  	else
>>  		ret = -ENOTTY;
>>  
>> +	vfio_group_unregister_notifier(group, nb);
>> +
>>  	up_read(&container->group_lock);
>>  	vfio_group_try_dissolve_container(group);
>>  
> 
> You haven't addressed the error paths, if the iommu driver returns
> error and therefore the {un}register returns error, what is the caller
> to expect about the group registration?
> 

Will change to:

	driver = container->iommu_driver;
	if (likely(driver && driver->ops->register_notifier))
		ret = driver->ops->register_notifier(container->iommu_data, nb);
	else
		ret = -ENOTTY;
	if (ret)
		goto err_register_iommu;

	ret = vfio_group_register_notifier(group, nb);
	if (ret)
		driver->ops->unregister_notifier(container->iommu_data, nb);

err_register_iommu:
	up_read(&container->group_lock);
	vfio_group_try_dissolve_container(group);

err_register_nb:
	vfio_group_put(group);
	return ret;


--
Thanks,
Jike