OF_DYNAMIC node lifecycle

[Grant Likely]

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.

g.