Re: [PATCH 21/38] workqueue: add missing put_device call

Levente Kurusa
2013-12-19T15:42:22Z

[+Cc Greg]

On 12/19/2013 04:34 PM, Tejun Heo wrote:
> Hello,
>
> On Thu, Dec 19, 2013 at 10:31 AM, Levente Kurusa <levex@linux.com> wrote:
>> The reason I removed the kfree() was because the put_device() will decrement
>> wq_dev->dev's reference count to zero (it is set to one by device_register) and hence the
>> wq_device_release() will be called. Now, this effectively does the same the kfree() call
>> would have done but also driver core is notified.
>
> Yeah, I know it does the same thing. It's just not the right way to do it.
>
>> Also, if you take a look at the comment for the device_register() function, it explicitly
>> says NOT to kfree the struct device, but instead call put_device() and let the device's release()
>> function take care.
>
> Greg, the API as described by the comment is really weird and
> unconventional. Failed calls are not supposed to have side effects
> which require explicit cleanup. Can we please update the comment?
>

Yes, it was already discussed that it would be more sane to have
device_register() call put_device() if it would fail, but Greg
said that the API was designed so that no kfree()s happen in the core.

--
Regards,
Levente Kurusa