Re: [PATCH v2 1/2] dma-buf: add reference counting for exporter module

Tomasz Stanislawski
2012-08-09T14:54:49Z

Hi Greg,

On 08/09/2012 04:23 PM, Greg KH wrote:
> On Thu, Aug 09, 2012 at 11:36:21AM +0200, Tomasz Stanislawski wrote:
>> This patch adds reference counting on a module that exported dma-buf and
>> implements its operations. This prevents the module from being unloaded while
>> DMABUF file is in use.
>
> Why force all of the modules to be changed "by hand", and not just do
> this automatically by changing the register function to include the
> THIS_MODULE macro in it? Much like the pci_register_driver() function
> is implemented in include/linux/pci.h?

Thank you for the hint.

The owner field belongs to dma_buf_ops structure that is often a 'const'
entity. Therefore owner field would have to be moved to 'struct dma_buf'
to avoid 'deconstification' issues.

Regards,
Tomasz Stanislawski

>
> That makes it impossible for driver authors to get it wrong, which is
> always a good sign of a correct api.
>
> thanks,
>
> greg k-h
>