[Question] refcount of DT node

[Pantelis Antoniou]

Hi Mark,

> On Apr 14, 2016, at 12:59 , Mark Rutland <mark.rutland at arm.com> wrote:
> 
> On Thu, Apr 14, 2016 at 09:48:49AM +0100, Russell King - ARM Linux wrote:
>> On Thu, Apr 14, 2016 at 04:47:57PM +0900, Masahiro Yamada wrote:
>>> Hi experts.
>>> 
>>> My understanding of refcount of DT node is poor.
>> 
>> The message from DT people is... don't worry about DT node refcounting.
>> Do whatever you want with it, they don't care whether you have correct
>> refcounting or not.
>> 
>> The background behind that is that I've tried to fix the refcounting,
>> and even had the coccinelle people generate some stuff to work on this
>> issue, but DT people's attitude towards it is "don't bother".
>> 
>> So yes, people may get it wrong, but it seems it's something that DT
>> people want ignored.
> 
> I'm not sure that's quite fair; the last discussion I recall about this
> ended up concluding that we need a better API, rather than papering over
> problems.
> 
> That said, there isn't much obvious progress on that front.
> 
> Frank, Pantelis, Rob, were there any conclusions on this from ELC, or is
> this something that needs someone to propose something?
> 

Frank mentioned that he wants a new API. I have some ideas about it too.

My take is that drivers should never do reference counting, we have to figure
out a way for DT access using copy semantics or locks.

References would still be required for core DT code, but that’s a sane subset.

> Mark.
> 
> [1] http://permalink.gmane.org/gmane.linux.drivers.devicetree/153777

Regards

— Pantelis