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. -Tyrel > > g. > > On Fri, Jun 27, 2014 at 8:41 AM, Nathan Fontenot <nfont@xxxxxxxxxxxxxx> wrote: >> On 06/27/2014 07:41 AM, Grant Likely wrote: >>> On Thu, 26 Jun 2014 15:01:49 -0500, Nathan Fontenot <nfont@xxxxxxxxxxxxxx> wrote: >>>> On 06/25/2014 03:24 PM, Grant Likely wrote: >>>>> On Tue, 24 Jun 2014 15:10:55 -0500, Nathan Fontenot <nfont@xxxxxxxxxxxxxx> wrote: >>>>>>>> heh! I have often thought about adding reference counting to device tree >>>>>>>> properties. >>>>>>> >>>>>>> You horrible, horrible man. >>>>>> >>>>>> Yes. I are evil :) >>>>>> >>>>>> After looking again the work needed to add reference counts to properties >>>>>> would be huge. The few properties I am concerned with are specific to powerpc >>>>>> so perhaps just adding an arch specific lock around updating those >>>>>> properties would work. >>>>> >>>>> Which code/properties? I'd like to have a look myself. >>>> >>>> /ibm,dynamic-reconfiguration-memory/ibm,dynamic-memory >>>> >>>> The property is updated in >>>> arch/powerpc/platforms/pseries/hotplug-memory.c:pseries_update_drconf_memory() >>> >>> Specifically, what do you need for the locking? Are you wanting to hold >>> off additional changes while that function is executing? Pantelis is >>> adding a mutex for device tree writers. Holding that mutex would prevent >>> any changes from happening in the tree without affecting readers. Would >>> that be sufficient? >> >> That would work. >> >> -Nathan >> > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@xxxxxxxxxxxxxxxx > https://lists.ozlabs.org/listinfo/linuxppc-dev > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
