Re: [Qemu-devel] [PATCH v10 01/19] vfio: Mediated device Core driver

[Jike Song]

On 10/29/2016 06:06 PM, Kirti Wankhede wrote:
> 
> 
> On 10/29/2016 10:00 AM, Jike Song wrote:
>> On 10/27/2016 05:29 AM, Kirti Wankhede wrote:
>>> +int mdev_register_device(struct device *dev, const struct parent_ops *ops)
>>> +{
>>> +   int ret;
>>> +   struct parent_device *parent;
>>> +
>>> +   /* check for mandatory ops */
>>> +   if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
>>> +           return -EINVAL;
>>> +
>>> +   dev = get_device(dev);
>>> +   if (!dev)
>>> +           return -EINVAL;
>>> +
>>> +   mutex_lock(&parent_list_lock);
>>> +
>>> +   /* Check for duplicate */
>>> +   parent = __find_parent_device(dev);
>>> +   if (parent) {
>>> +           ret = -EEXIST;
>>> +           goto add_dev_err;
>>> +   }
>>> +
>>> +   parent = kzalloc(sizeof(*parent), GFP_KERNEL);
>>> +   if (!parent) {
>>> +           ret = -ENOMEM;
>>> +           goto add_dev_err;
>>> +   }
>>> +
>>> +   kref_init(&parent->ref);
>>> +   mutex_init(&parent->lock);
>>> +
>>> +   parent->dev = dev;
>>> +   parent->ops = ops;
>>> +
>>> +   ret = parent_create_sysfs_files(parent);
>>> +   if (ret) {
>>> +           mutex_unlock(&parent_list_lock);
>>> +           mdev_put_parent(parent);
>>> +           return ret;
>>> +   }
>>> +
>>> +   ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
>>> +   if (ret)
>>> +           dev_warn(dev, "Failed to create compatibility class link\n");
>>> +
>>
>> Hi Kirti,
>>
>> Like I replied to previous version:
>>
>>      http://www.spinics.net/lists/kvm/msg139331.html
>>
> 
> Hi Jike,
> 
> I saw your reply but by that time v10 version of patch series was out
> for review.
> 

Ah..yes, I forgot that :)

>> You can always check if mdev_bus_compat_class already registered
>> here, and register it if not yet. Same logic should be adopted to
>> mdev_init.
>>
>> Current implementation will simply panic if configured as builtin,
>> which is rare but far from impossible.
>>
> 
> Can you verify attached patch with v10 patch-set whether this works for you?
> I'll incorporate this change in my next version.
> 

Seems cool. But would you please also keep the register in mdev_init(),
just check the 'in case it was already registered' case? Thanks!

--
Thanks,
Jike