OF_DYNAMIC node lifecycle

[Grant Likely]

On Wed, Jul 16, 2014 at 2:57 PM, Grant Likely <grant.likely at linaro.org> wrote:
> On Wed, Jul 16, 2014 at 12:30 PM, Tyrel Datwyler
> <turtle.in.the.kernel at gmail.com> wrote:
>> On 07/15/2014 10:33 PM, Grant Likely wrote:
>>> I've got another question about powerpc reconfiguration. I was looking
>>> at the dlpar_configure_connector() function in dlpar.c. I see that the
>>> function has the ability to process multiple nodes with additional
>>> sibling and child nodes. It appears to link them into a detached tree
>>> structure, and the function returns a pointer to the first node.
>>>
>>> All of the callers of that function then call dlpar_attach_node(),
>>> which calls of_attach_node(). However, of_attach_node() only handles a
>>> single node. It doesn't handle siblings or children. Is this a bug?
>>> Does the configure connector ever actually receive more than one node
>>> at once?
>>
>> Yes, it is sometimes the case we will get a tree structure back of more
>> than one node. Under the proc interface implementation this just worked.
>> With the move to sysfs it appears we have a regression here. What makes
>> more sense here, for us to walk the tree calling of_attach_node, or to
>> move such tree walking logic into of_attach_node? From what I can tell
>> we are the only consumers of of_attach_node.
>
> That is very shortly going to change. The overlay code also uses
> of_attach_node(). I can make of_attach_node() recurse over
> descendants, but I'm also considering moving the powerpc code over to
> the of_changeset series that Panto and I are working on.
>
> Either way, the handling of multiple nodes should be common code. I
> think the easiest is to put the recursion into of_attach_node(), at
> least for fixing the bug. It can be reworked later.

On pseries, do notifiers ever fail? ie. Does the reconfig code ever
object to a DT change and prevent it from being applied?

g.